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CN-116583394-B - Method and apparatus for producing solid foam, product and use

CN116583394BCN 116583394 BCN116583394 BCN 116583394BCN-116583394-B

Abstract

The present application relates to a method and apparatus for continuously producing solid foam. A homogeneous suspension is formed from the raw materials, wherein the suspension includes a curing agent, and a foam mixture including bubbles is formed by mixing bubbles into the suspension. The foam mixture is injected through at least one nozzle to form a foam pattern and the foam pattern is laid on a moving surface and the foam mixture of the foam pattern is cured to form a solid foam such that the bubbles of the foam mixture contract in a non-lengthwise direction to form shaped bubbles. Furthermore, the application relates to the use of the product, as well as the method.

Inventors

  • M. Arawa
  • KOIVISTO JANNE
  • A. Pusto

Assignees

  • 沃阿米公司

Dates

Publication Date
20260512
Application Date
20211004
Priority Date
20201005

Claims (20)

  1. 1. A method for continuously producing a solid foam, wherein a suspension is formed from a raw material, air is added to the suspension to form a foam mixture, and foam is formed from the foam mixture, characterized in that the method comprises Forming a homogeneous suspension from a biobased feedstock comprising fibers, wherein the suspension comprises a solidifying agent, Adding a surface tension reducing, viscosity increasing chemical to the suspension, the chemical selected from one of methylcellulose, derivatives of methylcellulose, carboxymethylcellulose, hydroxypropyl cellulose, ethylcellulose, or combinations thereof, -Forming a foam mixture comprising bubbles by mixing bubbles into the suspension, and -Processing the foam mixture by an extruder and injecting the foam mixture from the extruder via at least one nozzle to a moving surface to form a foam pattern comprising parallel foam strips to produce a rod-like structure, and laying the foam pattern on the moving surface, and curing the foam mixture of the foam pattern with heat so as to form an anisotropic solid foam comprising bubbles, such that the bubbles of the foam mixture shrink in non-length directions to form elongated bubbles in the foam.
  2. 2. The method of claim 1, wherein the chemical is a photopolymer.
  3. 3. The method of claim 1, wherein a solid fibrous material is added to the feedstock and/or the suspension and is selected from the group consisting of carbon fibers, carbon nanotubes, graphene, laponite, hemp, polymers, and combinations thereof.
  4. 4. A method according to claim 3, wherein the solid fibrous material is polystyrene.
  5. 5. A method according to claim 1, characterized in that solid fibre material is added to the raw material and/or the suspension and the solid fibre material is a carbon net.
  6. 6. A method according to claim 1, characterized in that solid fibre material is added to the raw material and/or the suspension and that the solid fibre material is yarn.
  7. 7. The method of claim 1, wherein the bio-based feedstock is biomass.
  8. 8. The method of claim 1, wherein the bio-based feedstock is selected from the group consisting of a treated bio-based material, an untreated bio-based material, or a combination thereof.
  9. 9. The method of claim 1, wherein the bio-based feedstock is a bio-based residual material.
  10. 10. The method of claim 1, wherein the bio-based feedstock is a forest-based material.
  11. 11. The method of claim 1, wherein the bio-based feedstock is a wood-based material.
  12. 12. The method of claim 1, wherein the bio-based feedstock is wood.
  13. 13. The method of claim 1, wherein the bio-based feedstock is cellulose.
  14. 14. The method of claim 1, wherein the foam mixture is cured by heating, photocatalysis, crosslinking, freezing, or a combination thereof.
  15. 15. The method of claim 1, wherein the foam mixture is cured at a temperature of 1 ℃ to 90 ℃.
  16. 16. A method according to any one of claims 1 to 15, wherein the product is formed from one or more foam patterns.
  17. 17. An apparatus for the continuous production of solid foam, said apparatus comprising at least one mixer for forming a suspension from a raw material, at least one foam generator for forming a foam mixture by adding air to said suspension, and means for forming foam from said foam mixture, characterized in that, The mixer being for forming a homogeneous suspension from a biobased feedstock comprising fibres, wherein the suspension comprises a solidifying agent, The apparatus comprises at least one adding means for adding to the suspension a surface tension reducing, viscosity increasing chemical selected from one of methylcellulose, derivatives of methylcellulose, carboxymethylcellulose, hydroxypropyl cellulose, ethylcellulose, or a combination thereof, -The foam generator is for forming a foam mixture comprising bubbles by mixing bubbles into the suspension, and The apparatus comprises at least one extruder and at least one nozzle for injecting the foam mixture from the extruder to a moving surface to form a foam pattern comprising parallel foam strips to produce a rod-like structure, wherein the moving surface is moving linearly at a speed of 0.1 to 50 m/s and the moving surface is a moving plate and the foam pattern is laid on the moving surface, and at least one curing device comprising at least one heater for curing the foam mixture of the foam pattern by heating to form an anisotropic solid foam comprising bubbles such that the bubbles of the foam mixture shrink in non-length directions to form elongated bubbles in the foam.
  18. 18. The apparatus of claim 17, wherein the curing means comprises at least one heater for curing the foam mixture by heating, thereby using radiant, conductive, and/or convective heat.
  19. 19. The apparatus of claim 17, wherein the apparatus comprises at least one rheology modifier for modifying rheological properties.
  20. 20. The apparatus according to any one of claims 17 to 19, characterized in that the apparatus comprises at least one transport device for transporting the foam mixture or the solid foam to a storage area.

Description

Method and apparatus for producing solid foam, product and use Technical Field The present application relates to a method for continuously producing solid foam and an apparatus for continuously producing solid foam. Furthermore, the application relates to the use of the solid foam product and the method for continuously producing a solid foam. Solid foam, such as bio-based solid foam, can be produced, and products can be produced from the solid foam. Background The manufacture of bio-based solid foams by the liquid foam route appears to be a promising approach to obtain new lightweight materials. At present, due to slow drying in high temperature environments, foams produced using this approach also tend to relax the foam shape at the same time due to their isotropic structure. In many applications, a lightweight material with wood-like properties that has high strength in one direction and good thermal conductivity in the other direction would be beneficial. In particular, such anisotropic structures have better thermal insulation properties than isotropic structures. One way to produce anisotropic foams is using freeze casting, e.g. rawovens, n & borgstrom, l (n & Bergstrom, l.) (2017), nanocellulose-based foams and aerogels (Nanocellulose-based foams and aerogels: processing, properties, and applications), journal of materials chemistry a (Journal of MATERIALS CHEMISTRY A), 5 (31), 16105-16117, wherein the foam is first forced into an elongated shape by high pressure, then frozen using low temperature gas. After freezing, the pressure is reduced, causing water to separate out of the foam while maintaining its structural integrity. This method is quite expensive due to the energy consumption required for the machines and refrigeration required for high pressures. From WO2020011587A1 a porous material is known which consists of cellulose fibres and gluten. In this application, a method of producing a rigid biodegradable isotropic foam having a hydrophobic structure is described. A method of forming a fibre product is known from WO2015036659 A1. Continuous roll-to-roll (roll-to-roll) processes produce thin or large paper-like sheets. Here, fiber formation is focused on die casting, which is not scaled up, and continuous processes. In addition, the foam is said to be an isotropic mixture, not anisotropic, nor elongated. Thus, the foam does not have significant orientation-dependent strength differences. A heat insulating panel is known from US 10,357,936. In the insulation panel, the protective cover and the insulation layer are bonded together. Furthermore, improvements in particle stabilized fluid-fluid interfaces are known from US20110111998A1, a tubular film manufacturing apparatus is known from JP5254982B2, a silver nanowire conductive ink for screen printing and a method for its preparation are known from CN201810602082a, a composition comprising an internal phase dispersed in a hydrophilic continuous phase is known from US 9789456B2, a differential expansion absorbing structure is known from US7799967B2, a flame retardant wood plastic composite is known from US 979034B2, a method for producing honeycomb cavities in thermoplastic materials is known from US4104207a, wherein the bubble forming medium is bound to a carrier, a shaped nanoporous body is known from US20190022623A1, and a base material, a method for its production and its use are known from EP2114645B 1. Disclosure of Invention The method, apparatus, product and use are characterized by what is presented below. In a method and apparatus for continuous production of solid foam, a suspension is formed from a raw material, a foam mixture is formed from the suspension, and the foam mixture is injected and cured to produce solid foam. A method for continuously producing a solid foam may include the steps of forming a uniform suspension from a feedstock, wherein the suspension includes a curing agent, forming a foam mixture including bubbles by mixing bubbles into the suspension, and injecting the foam mixture through at least one nozzle, such as through at least one nozzle, to form a foam pattern, laying the foam pattern on a moving surface, and curing the foam mixture of the foam pattern to form a solid foam such that the bubbles of the foam mixture contract and deform in a non-length direction to form shaped bubbles. The shrinkage and deformation process of the foam mixture and bubbles may occur during injection of the foam mixture, between the nozzle and the moving surface, and/or in conjunction with the nozzle during curing. In one embodiment, an anisotropic solid foam is formed. Anisotropy can be used for excellent thermal insulation and mechanical properties of solid foam materials. Anisotropic solid foams are difficult to prepare because basic foam physics causes the foam shape to relax to an isotropic shape immediately after the external stress is removed. In wet bio-based foam manufacture, this occurs during the drying process. Thus, in