WO2024208821A1

WO2024208821A1 - Method of manufacturing a composite material comprising shells of mussel and/or oyster

Info

Publication number: WO2024208821A1
Application number: PCT/EP2024/058928
Authority: WO
Inventors: Bjarne Hammer
Original assignee: Studio Hammer / Arkitektur and Design
Current assignee: Studio Hammer / Arkitektur and Design
Priority date: 2023-04-03
Filing date: 2024-04-02
Publication date: 2024-10-10
Anticipated expiration: 2025-10-03

Abstract

The invention relates to a method of manufacturing a composite material comprising shells (1) of mussel and/or oyster. The shells and a binder (2) are provided, typically with the shells being in an amount of 70 to 98 weight%. The shells are granulated, typically to have an average size of 0.1 to 10 mm, such as 0.5 to 10 mm. The granulated shells are mixed with the binder by use of a mixer (3) which provides a rotational movement resulting in melting of at least a part of the binder. The mixing is performed until the mixed shells and binder have formed a paste (6). The paste is removed from the mixer and can be formed to a shaped composite element (7) whereafter the paste is allowed to solidify. The composite element may be a building element, such as a door, window frame, lamphouse, slab, roof tile, façade panel, tabletop, or ceiling panel.

Description

METHOD OF MANUFACTURING A COMPOSITE MATERIAL COMPRISING SHELLS OF

MUSSEL AND/OR OYSTER

FIELD OF THE INVENTION

The present invention relates to a method of manufacturing a composite material comprising shells of mussel and/or oyster. In particular, it relates to a method in which the shells are mixed with a binder in a process resulting in a paste that can be formed into a composite element e.g. by the application of pressure.

BACKGROUND OF THE INVENTION

It is known to manufacture composite materials where plastic is the primary material (up to 80% or more) and additional materials other than shells are added. Such additional materials may e.g. be wood chips, powder or granules of waste materials or metal powder and/or crushed stone. Examples of well-known brands include Corian, Geta Core, and Silestone where quartz, glass, or aluminium is included together with binding agents, such as artificial resin or acrylic material.

It is also known to make composite materials in which mussel shells are included. Mussel shells are residual products from the industrial production of mussels from which the meat is extracted for the production of food or livestock feed. The shells are typically considered a waste product and are used for landfill or to a lesser extent for the bottom of horse tracks or for drainage layers.

Composite materials comprising mussel shells can generally be grouped into three categories:

A) Composite materials in which mussel shells are included and the binding material is e.g. fibre cement or a corresponding material.

B) Composite materials in which mussel shells are included with a few weight percent and the binding material is a large percentage of plastic.

C) Composite materials in which mussel shells are included as mentioned under B and to which is also added metal powder or stone-based aggregate. It is also known to incorporate mussel shells in liquid products for surface treatment.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a method of manufacturing a composite material that is an alternative to known materials typically used in the building industry, such as aluminium, steel, plastic, and natural stone.

It is an object of at least some embodiments of the present invention to provide a method of manufacturing a composite material comprising shells of mussel and/or oyster, which method allows for the manufacturing of composite elements suitable for use in the building industry, such as for load bearing elements.

It is an object of some embodiments of the present invention to provide a method of manufacturing a composite material which is more environmentally friendly than similar products made from traditional materials, such as metal.

It is a further object of the present invention to provide an alternative to the prior art.

SUMMARY OF THE INVENTION

Thus, the above-described object and several other objects are intended to be obtained in a first aspect of the invention by providing a method of manufacturing a composite material comprising shells of mussel and/or oyster, the method comprising the following steps: providing the shells and a binder,

- granulating the shells, mixing the granulated shells with the binder by use of a mixer, the mixer providing a rotational movement resulting in melting of at least a part of the binder, performing the mixing until the mixed shells and binder have formed a paste, and removing the paste from the mixer. An advantage of a composite material comprising shells of mussel and/or oyster is that during the growth of the shells, CO2 is stored therein. Thus, this amount of CO2 remains in the product made from the composite material and thereby limits the amount of CO2 emitted into the atmosphere.

The process used for the mixing of the shells and the binder so that the paste is formed can be referred to as a thermo-kinetic process, because the mutual movement of the constituents results in the generation of heat. The resulting melting allows the binder to adhere to the non-melted shells and thereby form a coherent paste which after solidification provides a resistant material that is homogeneous on the surface and has high compressive strength and stiffness.

The temperature needed for the melting of at least a part of the binder will depend on the actual binder used. For some types of binder and/or for some amounts of materials, it may be advantageous to pre-heat the granulated shells and/or the binder before it is supplied to the mixer. For some embodiments of the invention, it may also be advantageous to use a heated chamber, such as to supply heat to the chamber during the mixing. However, it should be ensured that the temperature does not become so high that it causes degradation of the shells.

What is referred to as "granulating" could also be referred to as "crushing and granulating". With such wording, the crushing may then refer to a first part of the process, and the granulating may refer to a second part of the process, even if both parts of the process happen simultaneously or overlapping. The granulating may e.g. be performed in a hammer mill.

Preferably, the rotational movement results in melting of all or substantially all of the binder. However, the scope of protection also covers embodiments in which small amounts of binder remain as solid, un-melted regions in the composite material.

By "paste" is meant a thick, soft, and resilient substance made by mixing a liquid with a powder. In the context of the present application, the liquid is the melted binder, and the powder is the granulated shells. The paste preferably has a condition in which it is configured to be formed to a shaped composite element as will be explained below. The viscosity of the paste should be so that it allows for the necessary handling of the paste during the transfer from the mixer to the location or device used for the subsequent step of forming to be described below. The viscosity should be low enough to allow for the forming and high enough to ensure that the shaped composite element keeps the desired geometry. The paste could also be referred to as a dough due to it being a material whose mechanical properties are somewhere between those of a viscous liquid and an elastic solid.

In presently preferred embodiments of the invention, the binder is provided in solid form until being mixed with the granulated shells in the mixer. This is different from processes in which a composite material is manufactured by use of a binder, also referred to as resin, which is provided in a liquid or viscous state. Thus, by a method according to the present invention, a step of pre-melting the binder can be avoided.

In addition to the components mentioned above, some embodiments of the invention also comprise the addition of fire retardants or anti-bacterial components to the material being formed into the paste. Such additives may e.g. be the same as known from traditional polymer composites. They may also be specially selected to prevent growth of possible bacteria present in shells of mussel and/or oyster. Furthermore, it may additives that provide an anti-bacterial effect to the composite elements being made from the composite material. This may e.g. be relevant when the composite element is a door handle. Such a built- in anti-bacterial effect may remain in the material for several years, such as for up to 30 years.

It may further be possible to add colour pigments to the paste. They may be added in the form of pulverized naturally occurring materials of any desired colour.

It may also be possible to add fibres, such as natural fibres made from e.g. flax or hemp, in order to increase the stiffness, strength and impact strength of the material. Preferably only plant-based reinforcement is used. In some embodiments of the invention, the method further comprises the steps of:

- forming the paste to a shaped composite element, and

- allowing the paste to solidify.

In some embodiments of the invention, the shells are granulated to have an average size of 0.1 to 10 mm, such as 0.5 to 10 mm, such as 1 to 8 mm, such as 1 to 5 mm. These sizes have been selected as they provide a characteristic pattern or finish of the final, shaped composite element. Furthermore, these sizes have been found to provide the desired mechanical properties, such as strength and stiffness, due to the possibility of having the granulated shells arranged in a laminated manner. If the granulated shells are too large, it is difficult to obtain a homogenous paste. Too large, granulated shells may also result in undesired defects in the material, if the volume-to-surface ratio is so high that the binding between the granulated shells becomes insufficient to form a coherent material with an even, smooth, and homogenous surface. Preferably, at least 80 weight%, such as at least 90 weight% of the shells have a size between 1 and 5 mm. In addition to such a laminated arrangement of the granulated shells, each shell also has a laminated structure. Both kinds of lamination add strength and stiffness to the material.

In some embodiments of the invention, two or more different size fractions of the granulated shells are used. As an example, the granulated shells may be a mixture of shell powder having a size of 0 to 200 microns, and coarser shells having a size of 1 to 3.5 mm. Which sizes to use and in which fractions, will be determined based on mechanical as well as aesthetic properties. By having a wide range of sizes, including both coarser shells and powder, a better packing can be obtained. This can provide for both a higher strength and a smoother and more homogeneous surface than what is obtainable when only coarse shells are used.

The amount of shells in the composite material may be 70 to 98 weight%, such as 75 to 95 weight%, such as 80 to 92 weight%, such as 85 to 92 weight%, such as 90 weight%. The amount of shells for a given application is typically chosen as part of a design process while taking into account at least some of the following parameters: the mechanical properties, the viscosity/formability of the paste, and the desired aesthetic effect of the shaped composite element. The mechanical properties include the strength and the stiffness. It also has to be taken into account that a too low amount of binder may cause insufficient amount of binding and thereby undesired cracks that can negatively influence the impact strength of the composite element. The correct composition will typically be determined based on experimental tests and/or computer simulations. The granulated shells have a high lime content, and their structure promotes a lamination effect. At the same time, the granulated shells form a high surface area where the binder gets a corresponding large binding surface.

The shells may be selected from one or more of the following:

- Common mussel, such as Mytilus edulis, or the family Mytiljdae,

- Scallop, such as Chlamys varia, the family Mimachlamys variam, or Pectinidae,

- Cockle, such as Cerastoderma edule, or the family Cardijdae,

- European oyster, such as Ostera edulisor, or the family Ostreidae, and

- Pacific oyster, such as Crassostrea gigas, Magallana gigas, or the family Ostreidae.

Which kind of shells to use for a given application may depend e.g. on the desired aesthetic effect, the desired mechanical properties, and what is available at a given time and location. As mentioned above, it is known that mussel and oyster shells store CO2, and therefore composite materials and composite elements manufactured by a method according to the present invention also store CO2.

The shells are typically received as waste material, so-called "left over", from industrial production of food or livestock feed. In some embodiments of the invention, the shells have been cleaned before being granulated, the cleaning comprising one or more, such as all, of the following steps:

- washing to remove possible sand and other dirt,

- heating at a temperature of 70 to 90 degrees Celsius to remove possible salmonella bacteria, and

- heating to a temperature of 130 to 190 degrees Celsius to remove possible remains of meat or plants, such as seaweeds.

The temperature mentioned should preferably not significantly exceed what is needed for the cleaning, since much higher temperatures have been found to influence the shells in a manner that typically causes degradation of the shells resulting in an undesired pulverisation during the granulation. Such a pulverisation would counteract the desired patterns, including lamination, obtainable by the process according to the present invention as described above. A pulverisation could also lower the strength and stiffness of the composite material.

The binder may be polymer, such as polypropylene (PP) or polyethylene (PE), and optionally at least a part, such as all, of the polymer may be recycled. The polymer may be any polymer that will melt to a sufficient extent to provide the needed binding effect at the manufacturing parameters used for a given application. The polymer is preferably a thermoplastic polymer. Recycled material may be referred to by adding an "r" in front of the traditional name. For example, recycled PP is referred to as rPP, and recycled PE is referred to as rPE. The binder is typically supplied in the form of flakes or pellets, but any suitable form of the polymer material is covered by the scope of protection. When the binder is a recycled material, it has undergone a sorting and cleaning before being used in the manufacturing according to the present invention. The recycled polymer may e.g. be provided from plastic bottles. By using recycled polymer, this material can find a new use which is advantageous at least from an environmental point of view. Thus, the shells are up-cycled biological material, and the polymer is recycled.

In alternative embodiments to those in which the binder is a polymer as described above, the binder is a bio-resin. A bio-resin is a thermoplastic made from plantbased materials instead of petroleum products. Thus, a bio-resin may also be referred to as a biobinder. Plants take in CO2 from the atmosphere and store it during growth. By using bio-resins in relation to the present invention, it is possible to manufacture composite materials that can be biodegraded, composted, and repurposed.

In some embodiments of the invention, the binder is a polymer to which a bioresin is added. In the present context, "polymer" is used to refer to traditional oilbased polymers. In some embodiments of the invention, the mixing is performed in a closed chamber comprising a rotor, and the closed chamber and/or the rotor rotates and thereby applies a rotational movement to the granulated shells and the binder so that resulting shearing forces cause a heating that melts at least a part of the binder. In some embodiments of the invention, the rotational speed of the closed chamber and/or the rotor is controllable. When both the chamber and the rotor rotate, they typically rotate in opposite directions. In at least some embodiments of the invention, this may result in a swivel speed of the material of around 3000 RPM or even higher. In some embodiments of the invention, the swivel speed of the material may be lower than 3000 RPM. As mentioned above, it may also be advantageous to use a heated chamber, such as to supply heat to the chamber during the mixing. This process can be referred to as induction process technology.

The granulated shells and the binder are typically fed into the chamber by use of a funnel. To allow for the mutual movement of the constituents, the volume of the chamber is significantly larger than the total volume of the constituents. As an example, a chamber with a volume of 5 litres has been found suitable for the mixing of 1.5 litres of constituents. In tests made during the development of the present invention, it was found that for the tested amounts, the desired mixing could be performed in approximately 30-90 seconds, such as 30 seconds. However, for larger amounts or other sizes of the granulated shells, more or less time may be needed. For some embodiments of the invention, it may take several minutes to, such as 5 to 10 minutes.

The process may be performed as either a batch process or a continuous process.

The step of forming may be performed by applying pressure, such as by use of a piston or rollers. The paste may e.g. be formed by pressing it into a mould.

In embodiments of the invention comprising a step of forming the paste to a shaped composite element, the step of forming may comprise:

- dividing the paste into a plurality of pellets which are allowed solidified and stored for later use,

- after storage, heating the pellets to form a mouldable material, and - forming the mouldable material into the shaped composite element.

In embodiments of the invention comprising a step of forming the paste to a shaped composite element, the method may further comprise: heating of the paste to increase the period in which it can be formed to a shaped composite element, and/or

- cooling of the shaped composite element to influence the solidification.

When the paste is heated, this may e.g. be done by feeding it to a press or rollers via a heated distribution chamber. When the shaped composite element is cooled, this may be done directly, such as instantaneously, or in a controlled manner over time via a cooling chamber and/or cooling surfaces. The cooling process may take from a few seconds to several minutes.

If desired, the shaped composite element can be placed in an ozone chamber to remove or reduce any odour from the material. Such an undesirable odour could otherwise remain in a final composite element or product which could lead to unpleasant environmental consequences and make the application of such an element or product unrealistic even when the mechanical properties are satisfactory.

In a second aspect, the invention relates to a composite element made from a composite material manufactured by a method according to the first aspect of the invention.

The composite element may be a building element, such as a building element selected from : door, window frame, lamphouse, slab, roof tile, fa ade panel, tabletop, or ceiling panel. These examples are components typically used in the building industry, but the scope of protection is not limited to this technical field.

The first and second aspects of the present invention may each be combined. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE FIGURES The method of manufacturing a composite material comprising shells of mussel and/or oyster according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 schematically shows the overall steps in a method according to the present invention.

Figure 2 schematically shows a possible cleaning of the shells before they are granulated.

Figure 3 schematically shows an alternative to the step of forming shown in figure 1.

Figures 4 to 7 show examples of composite elements which have been manufactured by methods according to the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

Figure 1 schematically shows the overall steps in a method according to the present invention. In this figure, the paste is formed into a shaped composite element in the form of a plate. The shells 1 are provided and granulated, typically to have an average size of 0.5 to 10 mm, such as 1 to 8 mm, such as 1 to 5 mm.

Then the granulated shells 1 are mixed with a binder 2 by use of a mixer 3. The binder 2 is shown as being provided in granulate form. The mixer 3 provides a rotational movement resulting in melting of at least a part of the binder 2. In figure 1, the mixer 3 is schematically shown as a closed chamber 4 wherein the mixing is performed by use of a rotor 5. The closed chamber 4 and/or the rotor 5 rotates and thereby applies a rotational movement to the granulated shells 1 and the binder 2 so that resulting shearing forces cause a heating that melts at least a part of the binder 2. The mixing is performed until the mixed shells 1 and binder 2 have formed a paste 6 which is then removed from the mixer 3. In the illustrated embodiment, the paste 6 is formed to a plate-shaped composite element 7 by applying pressure by use of rollers 8. Then the paste 6 is allowed to solidify.

In some embodiments, the invention includes a thermo-kinetic process which can be described as follows: The mixing of the material is performed in a closed chamber which is typically cylindrically shaped. The materials are introduced via a funnel. The quantity of the material is limited to e.g. 1.5 litres where the chamber has a volume of e.g. 5.0 litres. In the centre of the chamber, there is a rotor which could also be referred to as a propeller. When the process is started, the materials are thus flung around the chamber at a very high speed. As a result of the friction, this increases the temperature in the chamber from room temperature at start-up to 180-230 degrees Celsius. The materials that can melt at this temperature can thus bind to the materials that do not melt. This provides for a glue effect on the surface of the granulated shells. This process takes approximately 30 seconds, but the actual time can be controlled depending on the materials and the desired temperature for the melting of the binder. When a sufficient binding has been obtained, the composite material in the form of a formable paste can then be removed from the chamber and be ready for the further processing.

In other embodiments of the invention, the materials are preheated before being introduced into the mixing chamber. The mixer is built so that the chamber rotates one way, and the rotor rotates at high speed the opposite way; this can be referred to as a counter-current process. Both the chamber speed and the rotor speed can be controlled. This results in a temperature increase in the chamber which can be supplemented with additional heating if necessary. A sufficient temperature must be achieved for the binder to melt and adhere to the granulated shells. The process can be referred to as an Induction Process Technology.

As mentioned above, the method can be used to form a large number of composite elements 7, such as doors, window frames, lamphouses, slabs, roof tiles, fa ade panels, tabletops, or ceiling panels. Figure 2 schematically shows a possible cleaning of the shells 1 before they are granulated. In the embodiment in figure 2, the following three steps are shown, but the scope of protection also covers embodiment in which one or more, such as all, of these steps are performed:

A: Washing to remove possible sand and other dirt.

B: Heating at a temperature of 70 to 90 degrees Celsius to remove possible salmonella bacteria.

C: Heating to a temperature of 130 to 190 degrees Celsius to remove possible remains of meat or plants, such as seaweeds.

Figure 3 schematically shows an alternative to the step of forming shown in figure 1. In the embodiment in figure 3, the paste 6 is formed into a rod 7 which is then divided into a plurality of pellets 10 which are allowed to solidify and stored for later use. After storage, the pellets 10 are heated to form a mouldable material resembling the paste 6 in figure 1. This paste 6 can then be formed into the shaped composite element 7 e.g. by use of rollers 8 as shown in figure 1.

As mentioned above, the amount of shells 1 in the composite material may be 70 to 98 weight%, such as 75 to 95 weight%, such as 80 to 92 weight%, such as 85 to 92 weight%, such as 90%. Figures 4 to 7 show examples of composite elements which have been manufactured by methods according to the invention. The rulers in the photos show the size in cm. Figure 4 shows four different composite elements of which one is arranged upright to show the distribution of the shells through the thickness. The composite elements have been shaped by pressing in a mould, and some of them are in natural colour whereas others have had colour added during the mixing. Figure 5 shows two pressed elements of which the one to the right is arranged upright. The elements have rounded edges with a radius of curvature of 20 mm. Figure 6 shows two pressed elements of which the one at the bottom and right of the other is formed as a profile having a 90 degrees angle between the two visible sides thereof. Figure 7 shows a composite element which has been formed into an L-shape. This composite element has an elliptical cross-sectional shape.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

Claims

1. Method of manufacturing a composite material comprising shells (1) of mussel and/or oyster, the method comprising the following steps: providing the shells (1) and a binder (2),

- granulating the shells (1), mixing the granulated shells (1) with the binder (2) by use of a mixer (3), the mixer (3) providing a rotational movement resulting in melting of at least a part of the binder (2), performing the mixing until the mixed shells (1) and binder (2) have formed a paste (6), and removing the paste (6) from the mixer (3).

2. Method according to claim 1, wherein the binder (2) is provided in solid form until being mixed with the granulated shells (1) in the mixer (3).

3. Method according to claim 1 or 2, further comprising the steps of:

- forming the paste (6) to a shaped composite element (7), and

- allowing the paste (6) to solidify.

4. Method according to any of the preceding claims, wherein the shells (1) are granulated to have an average size of 0.1 to 10 mm, such as 0.5 to 10 mm, such as 1 to 8 mm, such as 1 to 5 mm.

5. Method according to any of the preceding claims, wherein the amount of shells (6) in the composite material is 70 to 98 weight%, such as 75 to 95 weight%, such as 80 to 92 weight%, such as 85 to 92 weight%, such as 90%.

6. Method according to any of the preceding claims, wherein the shells (1) are selected from one or more of the following:

- Common mussel, such as Mytilus edulis, or the family Mytiljdae,

- Scallop, such as Chlamys varia, the family Mimachlamys variam, or Pectinidae,

- Cockle, such as Cerastoderma edule, or the family Cardijdae,

- European oyster, such as Ostera edulisor, or the family Ostreidae, and - Pacific oyster, such as Crassostrea gigas, Magallana gigas, or the family Ostreidae.

7. Method according to any of the preceding claims, wherein the shells (1) have been cleaned before being granulated, the cleaning comprising one or more, such as all, of the following steps:

- washing (A) to remove possible sand and other dirt,

- heating (B) at a temperature of 70 to 90 degrees Celsius to remove possible salmonella bacteria, and

- heating (C) to a temperature of 130 to 190 degrees Celsius to remove possible remains of meat or plants, such as seaweeds.

8. Method according to any of the preceding claims, wherein the binder (2) is a polymer, such as polypropylene or polyethylene, and optionally wherein at least a part, such as all, of the polymer is recycled.

9. Method according to any of claims 1 to 7, wherein the binder (2) is a bio-resin in the form of a thermoplastic made from plant-based materials.

10. Method according to any of the preceding claims, wherein the mixing is performed in a closed chamber (4) comprising a rotor (5), and wherein the closed chamber (4) and/or the rotor (5) rotates and thereby applies a rotational movement to the granulated shells (1) and the binder (2) so that resulting shearing forces cause a heating that melts at least a part of the binder (2).

11. Method according to claim 3 or any of claims 4 to 10 when depending on claim 3, wherein the step of forming is performed by applying pressure, such as by use of a piston or rollers (8).

12. Method according to claim 3 or any of claims 4 to 11 when depending on claim 3, wherein the step of forming comprises:

- dividing the paste (6) into a plurality of pellets (10) which are allowed solidified and stored for later use,

- after storage, heating the pellets (10) to form a mouldable material, and

- forming the mouldable material into the shaped composite element (7).

13. Method according to claim 3 or any of claims 4 to 12 when depending on claim 3, further comprising :

- heating of the paste (6) to increase the period in which it can be formed to a shaped composite element (7), and/or

- cooling of the shaped composite element (7) to influence the solidification.

14. Composite element (7) made from a composite material manufactured by a method according to any of the preceding claims.

15. Composite element (7) according to claim 14, wherein the composite element (7) is a building element, such as a building element selected from: door, window frame, lamphouse, slab, roof tile, fa ade panel, tabletop, or ceiling panel.