268 results about "Supercritical fluid" patented technology

The embodiment of the invention provides a calculation method and device for boundary parameters of a supercritical fluid heat exchanger, computer equipment and a medium, and relates to the technical field of fluid mechanics and heat transfer science calculation.The method comprises the following steps that design parameters and target working conditions of the heat exchanger are obtained; calculating to obtain the single section length of each infinitesimal section; based on the initial inlet pressure guess value, according to the length of the single section and the pressure and the temperature of the infinitesimal section i, the pressure and the temperature of the infinitesimal section i + 1 are obtained through calculation, the difference value between the outlet calculation pressure and the target outlet pressure is calculated, and the difference value serves as a pressure error; if the pressure error is greater than the convergence tolerance, updating the inlet pressure guess value by adopting a numerical iteration method, and performing iteration again based on the inlet pressure guess value after iteration; otherwise, iteration is terminated, and the final inlet pressure value and the final outlet temperature value are output. According to the scheme, the calculation efficiency and accuracy of solving the inlet pressure and the outlet temperature of the supercritical fluid heat exchanger under the given target outlet pressure are improved.

The invention belongs to the technical field of high-performance polymer materials, and relates to thermal-crosslinkable polyimide, polyimide foam and a preparation method and application thereof. Aiming at the problem that the foaming performance of the existing polyimide foaming material is poor due to the fact that the melt strength and the chain segment activity are difficult to balance, the invention provides a method for regulating and controlling the rheological property by controlling the number-average molecular weight (Mn = 15-45kDa) of a precursor and introducing a thermally-crosslinkable end-capping group. The precursor can form a parison with a specific elastic network structure through hot-pressing cross-linking, and then the polyimide foam which is high in foaming rate, uniform and fine in foam hole, low in density and excellent in heat resistance can be prepared through a two-step method of supercritical fluid saturation pressure relief and high-temperature secondary foaming. The method realizes predictable control from molecular parameters to foaming performance, is suitable for various thermoplastic polyimide systems, and has a wide application prospect in the fields of aerospace heat insulation and the like.

The present application relates to the technical field of dielectric ceramic powder preparation, and particularly relates to a multilayer ceramic capacitor, a high-activity nano-barium titanate powder for the multilayer ceramic capacitor and a preparation method of the high-activity nano-barium titanate powder, the method comprising the following steps: (1) reacting a soluble barium salt with a precipitator to obtain barium carbonate precursor particles with high specific surface area; (2) uniformly coating nano-titanium dioxide particles on the surface of the barium carbonate precursor particles by using a supercritical fluid flash technology to form a composite precursor; and (3) performing a solid-phase synthesis reaction on the composite precursor and sintering to obtain nano-barium titanate powder. The present application, through the synergistic effect of the two means of "high-activity precursor preparation" and "nano-level uniform coating", prepares a composite precursor with extremely high specific surface area, surface energy and micro-uniformity, effectively reduces the heat sintering temperature, suppresses abnormal grain growth and lattice distortion, and significantly improves the tetragonality of the nano-barium titanate powder.

The invention provides a light-weight automobile appearance decorating part added with recycled waste and a forming process of the light-weight automobile appearance decorating part, and belongs to the technical field of automobile part manufacturing. The preparation method comprises the following steps: mixing a core layer melt containing polypropylene recycled after consumption, waste tire rubber and a styrene-ethylene-butylene-styrene block copolymer with a supercritical fluid to form a uniform dispersion; after an acrylonitrile-styrene-acrylate copolymer surface membrane is formed in a mold cavity, injecting the uniform dispersion to drive the membrane to extend and fill; and gas is induced to generate heterogeneous nucleation on the surfaces of the waste tire rubber particles through pressure relief and grow into bubbles. On the premise that the surface glossiness is not degraded, light weight and high toughness of the appearance decorating part and efficient utilization of renewable resources are achieved.

The invention relates to the technical field of foaming materials, in particular to a shoe material preparation process for finished shoes based on supercritical physical foaming and the finished shoes. The preparation method comprises the following steps: 1) weighing a matrix, octadecyl polyhedral oligomeric silsesquioxane, an active group-containing styrene-acrylonitrile copolymer, a polydimethylsiloxane block copolymer, an epoxy functional group-containing olefin copolymer, a nano silicon dioxide dispersion and a processing aid, uniformly mixing, blending, extruding, granulating and drying to obtain a blended material, wherein the matrix, the octadecyl polyhedral oligomeric silsesquioxane, the active group-containing styrene-acrylonitrile copolymer, the polydimethylsiloxane block copolymer, the epoxy functional group-containing olefin copolymer, the nano silicon dioxide dispersion and the processing aid are mixed uniformly; the preparation method comprises the following steps of (1) preparing a polymer, (2) plasticizing the blended material to form a preformed blank, injecting supercritical gas, and fully dissolving the supercritical fluid in the polymer at the temperature of 150-180 DEG C and the pressure of 10-20MPa for 1-3 hours, (3) reducing the pressure to normal pressure within 10 seconds at the pressure reduction rate of less than or equal to 2MPa / s, and (4) cooling and shaping at the temperature of 60-80 DEG C to obtain the shoe material.

Embodiments described herein provide a method of making a tobacco extract comprising; (a) contacting tobacco with an extraction solvent in a first chamber such that tobacco components are extracted from the tobacco into the extraction solvent, wherein the extraction solvent is a supercritical fluid in the first chamber; (b) passing the extraction solvent containing tobacco components along a line towards a second chamber, wherein a valve is present in the line and the conditions downstream of the valve are such that the extraction solvent is subcritical; and (c) pumping entrapment solvent into a flow downstream of the valve, wherein the tobacco components are released from the extraction solvent by transfer to subcritical conditions and are dissolved in the entrapment solvent, whereby the tobacco components dissolved in entrapment solvent are collected in the second chamber.

The invention belongs to the field of aerogel composite materials, and discloses a heat insulation and wave absorption integrated aerogel composite material which at least has a three-stage pore network structure, the secondary structure is a continuous carbon network and is loaded in pores of the primary structure; the tertiary structure is silicon oxide aerogel with nano pores, and is polymerized on the surface of the secondary structure and in the pores in situ. The aerogel composite material is low in heat conductivity coefficient, good in heat insulation performance, excellent in wave absorbing performance and high in mechanical strength. The invention further discloses a preparation method of the material, the carbon-silicon dioxide composite material prepared through sol-gel and supercritical fluid drying is low in aerogel density and small in pore diameter and has a good barrier effect on solid heat transfer and gas heat transfer, and the prepared composite material has low heat conductivity and good heat conductivity. The continuous carbon network endows the material with excellent wave-absorbing performance.

The utility model relates to the technical field of high polymer material forming processing, and discloses a foam microcellular foaming forming device based on supercritical fluid, which comprises a mixing box, a discharge valve, a placing cylinder, an L-shaped frame and a driver, an adjusting mechanism is arranged on the mixing box, an auxiliary mechanism is arranged on the adjusting mechanism, the adjusting mechanism comprises a rotary column, and the rotary column is arranged on the placing cylinder. A sliding plate is fixedly connected to the rotating column, a concave-convex opening is formed in the outer wall of the top of the containing barrel, a telescopic spring is fixedly connected to the outer wall of the bottom of the containing barrel, a compression spring is fixedly connected to the inner wall of the bottom of the sliding plate, and a scraping plate is slidably connected to the inner wall of the bottom of the sliding plate; the outer wall of the side, close to the compression spring, of the scraper is fixedly connected with a stirring rod. According to the utility model, the sliding plate and other structures are arranged, so that the problem that the quality of a final product is influenced due to the fact that a molten raw material and a mixture are not fully and uniformly stirred when supercritical fluid is mixed in a special plasticizing device is solved.

A substrate processing apparatus includes a first chamber in which a developing solution treatment process is performed, a second chamber in which a drying process is performed using a supercritical fluid, and a controller configured to control the first chamber and the second chamber, wherein the controller controls a first substrate to be placed in the first chamber, performs first cleaning on a processing space of the second chamber by using a supercritical fluid having a first state which does not satisfy a set condition, performs a developing solution treatment process on the first substrate placed in the first chamber, transfers the first substrate, on which the developing solution treatment process has been performed, from the first chamber to the second chamber, and performs a first drying process on the first substrate by using a supercritical fluid having a second state that satisfies the set condition.

The invention relates to a multifunctional crystalline protection layer based on a supercritical fluid and a preparation method and application thereof, in a treatment environment with the supercritical fluid as a treatment environment, a metal material to be modified reacts with a modifier, and a protection layer made of an inorganic metal compound material is formed on the surface of the material to be modified in situ. The size / volume ratio of the material to be modified to the supercritical fluid is (1-300 cm < 2 > * 100-500 [mu] m): (20-200 mL). Compared with the prior art, a uniform and compact crystalline inorganic mineral protective layer can be generated on the surface of the material, and manual control of the surface protective layer structure is achieved.

A system and method are disclosed that allow for determining the mass of a fluid within a container by first vibrating the outer surface of the container, where the container contains a fluid, such as a compressed fluid, a gas, a liquid, a mixture of gas and liquid, or a supercritical fluid. Vibration data is then received at the outer surface of the container, and the vibration data is then converted to one or more frequencies. The mass of the fluid in the container is then estimated based on the one or more frequencies.

The present application relates to the technical field of shaving board, in particular to a kind of light high-strength shaving board, including the surface layer, transition layer and core layer stacked in turn, and each layer has gradient pore structure, wherein: surface layer includes the closed hole formed by oriented arrangement of reinforcing fiber, nanocellulose and supercritical fluid foaming;Transition layer includes hollow microbead, surface modification shaving and microcapsule of chemical foaming agent coating;Core layer includes honeycomb light skeleton and aerogel reinforcement body.A kind of preparation method of the above-mentioned light high-strength shaving board is also provided.The present application can realize the coexistence of light weight and high strength, and solve the problem of interface combination and foaming control difficulty.

The present application belongs to the technical field of food processing, and particularly relates to a biological preservative, a preparation method thereof and application of the biological preservative in baked foods. In view of the poor dispersibility of natamycin in aqueous solution and the poor high-temperature resistance of the biological preservative, the present application first uses supercritical CO2 fluid to prepare soluble soybean polysaccharide microparticles which are small and have uniform particle size distribution, and then uses the microparticles and cotton oligosaccharides to form a double-layer interfacial film on the surface of the natamycin, thereby significantly improving the dispersibility of the natamycin in the biological preservative and greatly improving the high-temperature resistance of the biological preservative. The biological preservative prepared by the present application can be applied to baked foods, and can be sprayed on the surface of the baked foods immediately after baking, thereby effectively prolonging the shelf life of the baked foods at room temperature.

The application provides a shell-shaped product with a cavity, a forming die and a preparation process, wherein the shell-shaped product comprises a main body part, the main body part comprises a bottom wall, a side wall and an opening opposite to the bottom wall, the bottom wall and the side wall are combined to form the cavity, the opening is connected with the cavity and an external space of the shell-shaped product, the main body part is integrally formed by a thermoplastic elastomer base material mixed with a supercritical fluid through a supercritical injection foaming forming process, and the closed cell rate of the main body part ranges from 10 to 99%, and the pore diameter ranges from 20 to 300 microns. The supercritical foaming process is adopted to realize the integral forming of the shell-shaped product, the process is simple, and production is efficient; the upper limit of the high closed cell rate and the micron-level pore diameter distribution can further improve the mechanical strength of the foaming material, and the obtained shell-shaped product can simultaneously have the characteristics of ultralow self-weight, natural waterproofness and strong mechanical performance, thereby providing a new idea for the manufacturing of products such as bags and the like.

The utility model discloses production equipment of polygonum viviparum nano delivery antidiarrheal particles, and relates to the technical field of polygonum viviparum production equipment, the production equipment comprises a polygonum viviparum nano production equipment main body, the lower side of the polygonum viviparum nano production equipment main body is fixedly connected with a fixed bracket; a discharging box is fixedly connected to the position, close to the polygonum viviparum nano production equipment body, of the inner side of the fixing support, the upper side of the discharging box is fixedly connected to an inner cavity of the polygonum viviparum nano production equipment body in a penetrating mode, a discharging pipe is fixedly connected to the lower end of the discharging box in a penetrating mode, and a fixing plate is fixedly connected to the outer side of the discharging pipe; the fixed plate is fixedly connected to the inner wall of the fixed support, one side of the fixed support is fixedly connected with a servo motor, raw materials of the polygonum viviparum are poured in from a feeding port in one side of the polygonum viviparum nanometer production equipment body, and then the polygonum viviparum nanometer production equipment conducts supercritical fluid and high-pressure collision technology on the polygonum viviparum to obtain the polygonum viviparum nanometer production equipment. Nanoscale forming of the polygonum viviparum particles is achieved, then the polygonum viviparum particles flow into a discharging box on the lower side, and then discharging is conducted through a discharging pipe.

The utility model discloses equipment for supercritical preparation of a catalyst for a small-diameter carbon nanotube, and belongs to the technical field of catalyst preparation. The equipment comprises a stock bin, a supercritical reactor, a primary cyclone separator and a secondary cyclone separator. The supercritical reactor is used for heating and pressurizing the catalyst stock solution to a supercritical state and carrying out catalytic reaction. The primary cyclone separator is connected with an outlet pipeline of the supercritical reactor and is used for separating catalyst particles; and the second-stage cyclone separator is connected with an outlet pipeline of the first-stage cyclone separator and is used for further separating catalyst particles. The equipment disclosed by the utility model is simple in structure, can preliminarily realize continuous preparation of the catalyst, preliminarily classifies catalyst particles, lays a foundation for accurately controlling the particle size distribution of the catalyst, and is suitable for preparing the catalyst for the small-diameter carbon nanotube.

Fabric compositions impregnated with beneficial agents are disclosed herein. The use of supercritical fluid (SCF) methods for impregnating fabric materials, such as apparel fabric materials, with beneficial agents (e.g., antimicrobial agents, antibacterial agents, etc.) is also disclosed herein.

The invention relates to a nano tackifying fluid and supercritical CO2 fluid synergistic fracturing method. In the target stratum development area, nano tackifying fluid and supercritical CO2 fluid are adopted for collaborative fracturing, sand-carrying fluid and displacing fluid are combined to form a fracture network, and the corresponding relation between the construction parameter combination and the fracture flow conductivity and the corresponding relation between the construction parameter combination and the fracturing construction fluid amount are established; based on the corresponding relation, a multi-target optimization model with the fracture conductivity maximization and the fracturing construction liquid amount minimization as the target is constructed, and through population initialization, non-dominated sorting, crowding distance calculation, crossover variation selection and iterative updating, a construction parameter optimization result is output. The shale reservoir fracture flow conductivity and the fracture network complexity can be improved, the construction liquid amount is reduced, and the fracturing transformation effect and economical efficiency are improved.

The neodymium iron boron grain boundary reconstruction method comprises the following steps that S1, a magnet is immersed in a low-concentration nitric acid-ethanol solution for ultrasonic cleaning, and tiny gaps are formed in the surface of the magnet; s2, dissolving a heavy rare earth organic complex by using a supercritical fluid, and performing pressure-maintaining permeation on the magnet treated in the step S1; s3, releasing the pressure to deposit the heavy rare earth organic complex in the magnet in situ; s4, heating the magnet treated in the step S3 under the protection of low vacuum or flowing inert gas to decompose the heavy rare earth organic complex into heavy rare earth oxide and organic matter, and heating and volatilizing the organic matter; s5, heating the magnet treated in the step S3 to 880-920 DEG C under the protection of low vacuum or flowing inert gas, and keeping the temperature for 6-10 hours; and S6, the magnet treated in the step S3 is cooled to 480-520 DEG C, heat preservation is conducted for 3-5 h, then air quenching cooling is conducted, the heavy rare earth source is sent to the center of the magnet through the supercritical fluid, the residual magnetism retention rate and the coercive force improving range are effectively increased, and meanwhile the production cost is reduced.

The application discloses a supercritical fluid foaming light-weight elastomer composite material for protective gear. The composite material is composed of a thermoplastic elastomer matrix, shear hardening microcapsules and a nucleating agent, and is formed by one-step injection molding foaming with supercritical nitrogen as a physical foaming agent. The composite material has a closed-cell microcellular structure, and the shear hardening microcapsules are uniformly distributed in the cell walls. The surface of the composite material has a dense unfoamed skin layer, and the whole presents a uniform matte white appearance. The shear hardening microcapsules are introduced into the cell walls, so that the protective gear is soft and comfortable at low-speed deformation, and is automatically hardened and enhanced to absorb energy at high-speed impact. The density of the composite material is as low as 0.50-0.90 g / cm3, and the composite material is suitable for sports protective gear, rehabilitation protective gear and protective equipment.

The utility model discloses a pressure reducing mechanism for supercritical fluid foaming, and relates to the technical field of pressure reducing mechanisms. Comprising a case, a connecting cover is inserted into one side of the case, first inserting grooves are formed in one sides of the bottom end and the top end of the connecting cover, second inserting grooves are formed in one sides of the first inserting grooves, a plurality of fixing rods corresponding to the first inserting grooves in a one-to-one mode are fixed to the top end and the bottom end of the case, the fixing rods are matched with the first inserting grooves, and the fixing rods are inserted into the second inserting grooves. The sides, close to the first inserting grooves, of the fixing rods are rotationally connected with rotating shafts. By arranging the connecting cover, the rotating rod, the fixed rod, the rotating shaft, the first slot and the second slot, the rotating rod is rotated to a vertical state, so that the rotating rod and the fixed rod are aligned with the first slot, then the connecting cover is moved outwards and taken out, and internal equipment can be maintained; and the case is prevented from being easily disassembled due to damage of the internal equipment, and the internal equipment is replaced and maintained.

The invention relates to an adsorption material and a preparation method and application thereof, and relates to the technical field of adsorption materials, the preparation method comprises the following steps: taking a charcoal raw material, ferrite and ferric salt as raw materials, heating and stirring under an alkaline condition, and then carrying out pyrolysis treatment to obtain a magnetic charcoal material; and performing swelling treatment on the magnetic biochar material by using a CO2 supercritical fluid carrying imidazolium ionic liquid containing a sulfonic acid group to obtain a first magnetic biochar material and the like. On the basis of the prior art, a magnetic biochar material is subjected to combined and cooperative treatment mainly by adopting a CO2 supercritical fluid carrying acidic ionic liquid swelling treatment process and a corona discharge treatment process in a hydrogen peroxide-containing atmosphere in sequence; the removal efficiency of the obtained adsorption material on suspended solids and organic pollutants under the room temperature condition and the recycling stability are remarkably improved, so that the requirement of multiple times of recycling under the scenes of high suspended solids and high grease content such as cosmetic wastewater treatment can be met.

The utility model discloses an aerogel supercritical fluid drying device which comprises a first gas storage tank, a first reaction kettle and a first collecting tank, a first discharging port is formed in the upper end of the first gas storage tank, a first feeding port is formed in the upper end of the first reaction kettle, and a second discharging port is formed in the lower end of the first collecting tank. The first discharging port is connected with the first feeding port through a first connecting pipe, a second discharging port is formed in the upper end of the first reaction kettle, a second feeding port is formed in the upper end of the first collecting tank, the second discharging port is connected with the second feeding port through a second connecting pipe, a first partition plate is arranged in the first collecting tank, and a second partition plate is arranged in the second collecting tank. The first collecting tank is divided into a first cavity and a second cavity by the first partition plate, and a first coil pipe is arranged in the first cavity. According to the aerogel supercritical fluid drying device, through the first heating rod and the second heating rod, the supercritical fluid state of CO2 gas is guaranteed, and the good drying effect is achieved.

The invention provides a supercritical fluid foaming method of an EMAA material, which comprises the following steps of: 1, dipping an EMAA matrix in a high-pressure container with gas pressure P1 and foaming temperature T1 to finish primary foaming; secondly, after the first step is finished, the pressure in the high-pressure container is relieved to the environment pressure, and the high-pressure container is cooled to 10-30 DEG C; foaming in the high-pressure container with the gas pressure P2 and the foaming temperature T2 again so as to finish secondary foaming; and step 3, after the step 2 is finished, cooling and shaping to obtain the polymer foaming material. The invention also relates to applications. According to the invention, the supercritical fluid is used for foaming the EMAA material to prepare the functional EMAA lightweight foam material covering parameters of different hardness, density, wear resistance, salt mist erosion resistance and the like.

This invention belongs to the field of polyolefin preparation and relates to a method for preparing a polyolefin material with low metal impurities and resistance to precipitation. The method includes the following steps: (1) adding polyolefin resin raw material and fatty ketone solvent into the extraction vessel of a supercritical extraction device, introducing a gaseous medium into the extraction vessel, adjusting the temperature and pressure of the extraction vessel to make the gaseous medium be in a supercritical state, and treating the polyolefin resin raw material in a supercritical fluid; the fatty ketone solvent is C3-C 10 (1) At least one of the fatty ketone solvents; (2) Cooling and depressurizing to separate the polyolefin resin raw material from the solvent phase and drying it to obtain the polyolefin material with low metal impurities and resistance to precipitation. The method provided by the present invention has high efficiency in removing metal impurities from polyolefins and simultaneously achieves the removal and control of the content of soluble polymers, which significantly improves the purity and precipitation resistance of polyolefin resins.

This invention belongs to the field of ventilation and purification technology in tunnel construction, and particularly relates to an integrated dust removal system during underground tunnel blasting construction. The system includes: a ventilation module, an air purification device, a gas sensor, a controller, and a power supply mechanism. The power supply mechanism includes a generator and an energy storage unit, as well as a municipal power grid, a solar power generation module, a compressed air energy storage module, and a geothermal power generation module connected to the generator and energy storage unit. The geothermal power generation module uses a supercritical CO₂ fluid and methanol heat exchange cycle to drive a turbine to generate electricity. The compressed air energy storage module stores energy during off-peak electricity consumption and releases energy to generate electricity during peak electricity consumption. The air purification device has a filter screen and a filter element sequentially installed at the air inlet, and a multi-stage liquid filtration assembly sequentially filled with washing liquid. Another filter element is installed at the exhaust end. The controller automatically adjusts the operating power of the ventilation module and the air purification device based on the gas sensor detection signal.

The invention discloses a manufacturing process and equipment for a light high-brightness plastic product, and the process comprises the following steps: firstly, carrying out micro-foaming injection molding by utilizing thermoplastic resin containing supercritical fluid or a chemical foaming agent, and controlling the size and distribution of internal foam holes of a base material by regulating and controlling foaming process parameters, so as to adjust the light transmittance and haze of the base material; performing flame or plasma on-line modification treatment on the surface of the base material by utilizing an automatic surface treatment device in a mold opening or station switching process; finally, a polyurethane reaction system is injected into the surface of the modified base material through a reaction forming technology to form a polyurethane functional layer, and different optical functional areas can be achieved through partition injection or thickness control. Correlation type forming equipment matched with the technology integrates the functions of foaming injection molding, online interface modification and polyurethane reaction forming, in-mold integrated manufacturing of a lightweight foaming base material and a highlight functional surface layer is achieved, and the surface quality, the interface bonding performance and the optical regulation and control capacity of a product can be effectively improved.

The embodiments described herein generally relate to processing chambers incorporating a small thermal mass, which enable efficient temperature cycling for supercritical drying processes. The chambers generally include a body, a liner, and an isolation element that enables the liner to exhibit a small thermal mass relative to the body. The chambers are also configured with suitable equipment for generating and / or maintaining a supercritical fluid within a processing volume of the chamber.

The invention relates to a substrate processing apparatus and a method of cleaning a lock key. The present invention prevents a substrate from being contaminated by particles derived from a lock key and a member in contact with the lock key. A substrate processing apparatus for drying a substrate by replacing a liquid film formed on an upper surface of the substrate with a supercritical fluid is provided with: a pressure vessel having a drying chamber for drying the substrate therein; the cover body is used for blocking the opening of the drying chamber; the locking key is used for limiting the cover body to move from a closing position where the cover body closes the opening to an opening position where the cover body opens the opening; and a cleaning unit that cleans the lock key.

The present application relates to the field of processing high molecular substances into porous or honeycomb products or materials, and provides a manufacturing method of a lightweight mask, wherein silicon rubber, white carbon black and silicon oil are transported into a first roller cylinder of a planetary roller extruder for mixing, to obtain a mixture; the mixture and a vulcanizing agent are transported into a second roller cylinder for mixing, to obtain a mixed rubber; a mold is heated and filled with supercritical fluid; the mixed rubber is transported into a cavity of the mold, and the cavity is filled with supercritical fluid again for pressure adjustment, and the mixed rubber and the supercritical fluid are saturated; or the mixed rubber is transported into a third roller cylinder for pre-vulcanization treatment of heating and pressurizing, and then transported into the cavity of the mold for pressure relief, and the mixed rubber after the saturation reaction or the pre-vulcanization treatment is supercritically foamed, the amount of injection is controlled to achieve the purpose of completely filling the cavity, and a mask of high-quality supercritically foamed silicon rubber material is obtained.