EP1189736A1

EP1189736A1 - Composite bodies

Info

Publication number: EP1189736A1
Application number: EP00927618A
Authority: EP
Inventors: Hans Henrik Bache
Original assignee: Giantcode AS
Current assignee: Giantcode AS
Priority date: 1999-05-10
Filing date: 2000-05-10
Publication date: 2002-03-27
Also published as: AU4600800A; WO2000067973A1

Abstract

A method of forming a composite body comprising a pair of first and second solid bodies and an intermediate body binding the first and second bodies together, said method comprising arranging a spacing member defining the outer surfaces of the intermediate binding body such that a first surface part of the spacing member is in engagement with an adjacent surface of the first body, forming the second body in a deformable condition against and in contact with a second surface part of the spacing member opposite to said first surface part, solidifying said second body, and converting the spacing member into said intermediate binding body while maintaining the first and second bodies in their mutual position. For example, the first body may be a layer of metal, and the secodn body may be a high strength concrete, cast against a spacing member engaging the metal layer and incorporating uncured or inactive binder, prior to curing or activating the binder to convert the spacing member to intermediate binding body.

Description

Composite Bodies

This invention relates to a method of forming a composite body by binding together a pair of first and second bodies.

A pair of solid first and second bodies of the same material or different materials may be bound together by means of a glue, an adhesive or any other kind of binding material. This is conventionally done by forming a pair of substantially complementary surface parts on such bodies, applying adhesive or binding material to at least one of the complementary surface parts and thereafter pressing the complementary surface parts together. The complementary surface parts may be obtained by moulding or casting said second body against a first surface part of the first body which is made from a solid or solidified material. In such case, where the first body is used as a mould surface or mould part when moulding or casting the second body from a material different from that of the first body, it is quite often not possible to obtain a bond between the bodies which is able to transfer sufficiently large tensile and shear stresses. In order to obtain a satisfactory bond between the complementary surface parts of the first and second bodies it is necessary to remove them from each other, apply a binder to at least one of the complementary surface parts and then reposition the bodies such that the complementary first and second surface parts are in mutual contact.

This known method is rather complicated and time consuming. Furthermore, in many situations this known method of applying binding material or adhesive to the complementary surface parts can not be used, for example when the first and second bodies are extremely heavy and/or when the first body is partly or totally embedded within the second body, which has been moulded or cast around he first body.

The present invention relates to a method of forming such composite body in a new way. The method also enables the production of composite bodies wherein two solid bodies having quite different properties, for example different coefficients of expansion or different toughness, may be joined via a compliant intermediate binding body. Thus, the present invention provides a method of forming a composite body comprising a pair of first and second solid bodies and an intermediate body binding the first and second bodies together, said method comprising arranging a spacing member defining the outer surfaces of the intermediate binding body such that a first surface part of the spacing member is in engagement with an adjacent surface of the first body, forming the second body in a deformable condition against and in contact with a second surface part of the spacing member opposite to said first surface part, solidifying said second body, and converting the spacing member into said intermediate binding body while maintaining the first and second bodies in their mutual position.

The first body may be preformed in the required shape or it may be formed as part of a sequential method according to the invention whereby the first body is formed and the spacing member is then arranged as specified above prior to carrying out the other steps of the method.

According to the invention the spacing member is converted into the intermediate binding body. Such conversion is performed without substantially changing the mutual position of the first and second bodies. In this connection, where conversion of the spacing member to the intermediate binding body results in some slight expansion or shrinkage, methods are available as discussed below to minimise relative displacement of the two bodies. This means that the method according to the invention may be used not only when the first and second bodies have a size and shape which would have allowed application of an adhesive or a binder in a conventional manner, but also when the first and second bodies are so large and heavy that they are difficult or impossible to separate and reposition and/or when the first body is at least partly embedded in or surrounded by the solidified second body.

For conversion to the intermediate binding body, the spacing member may consist of or comprise a binding material which is inactivated or which has simply not yet developed its active binding property, and its conversion may include activating said binding material or allowing the binding material to develop its binding property so as to bind the first and second bodies together by the binding material. An example of a binding material which has not yet developed its active binding property is a fluid two-component adhesive after its two components have been mixed, but before the reaction between the two components has proceeded to such an extent that the adhesive has cured. Activation of inactivated binding material may for example comprise heating, melting, irradiating or otherwise curing the inactivated binding material or application of a solvent or a binder component or binder activator in a fluid state, such as a liquid or gaseous state, etc.

In order to facilitate the introduction of a solvent or a binder component or binder activator, the spacing member may define one or more inner cavities therein for receiving such solvent or binder component or binder activator. When the various binder components have activation of the binding material, the binder eventually solidifies and forms together with possible parts of the spacing member not being binder components the solidified intermediate body.

The spacing member may consist entirely of inactivated binder, which is converted to the intermediate binding body by curing after solidification of the second body, or it may comprise parts not being components of the binder. In the latter case, the spacing member may be a non-binding structure which intrinsically or together with the first and second surface parts of the first and second bodies may define one or more cavities containing, or for receiving, inactivated binder. Conversion of the spacing member to intermediate binding body is then achieved by introducing a not yet cured binder, such as a two component epoxy, polyurethane or acrylate/acrylonitrile adhesive, into such cavities (if not already present) and curing the composite of non- binding structure and binder. It is important, however, that the binder present in the spacing member after such conversion to intermediate binding body is in intimate contact with the opposite surface parts of the first and second solid/solidified bodies. Therefore, the spacing member must be adapted to allow and secure such contact. Thus the binder may be caused via said cavity or cavities to come into contact with said opposite first and second surface parts of the spacing member and the adjacent surface parts of said first and second bodies engaging therewith, whereby the desired strong bond may be obtained.

In the case of the composite intermediate binding body discussed above, on one hand, the said second surface part of the spacing member against which the second body is formed in a deformable condition, for example by casting, should be of a structure sufficiently tight to prevent the casting material of the second body from penetrating into possible inner cavities of the spacing member. On the other hand, it should be possible to bring a binder being injected into such inner cavity or cavities into contact with the opposite adjacent surface parts of the spacing member and the body surfaces engaging therewith. Therefore, the said first and second surface parts of the spacing member may have a plurality of small openings defined therein communicating with the cavity or cavities of the spacing member. As an example, the spacing member may define a porous matrix structure. Thus, when the binder is injected or introduced into the porous structure it may be caused to come into contact with the surface parts of the first and second bodies being in engagement with the opposite first and second surface parts of the spacing member, respectively. The spacing member may include one or more curing components of the binder or binder component being introduced. Thus, for example, the spacing member may be formed partly or exclusively by one or more components of a binder composition requiring a counterpart component for activation being of a porous or cellular structure, and the binder may then be activated by injecting as a fluid or gaseous binder counterpart into the pores or cells of the spacing member.

As another possibility, the spacing member may be made from a substance or material which may be totally or partly removed, for example by heating it to a melting or evaporation temperature, or the spacing member may be made from a material and/or have a form allowing reduction of its volume when exposed to a treatment, such as a heat treatment. As an example, the spacing member may be hollow or porous so as to collapse when exposed to heat. When the volume of the spacing member has been reduced and/or the spacing member has been removed partly or totally form the space defined between said first and second solidified bodies, the idle space may be filled up with a binder.

Each of the first and second bodies may be made from any suitable material, such as metals, metal alloys, plastics or plastics-based materials, wood, glass, gypsum, solidified, including frozen, liquids, ceramics, including chemically bonded ceramics such as cement paste, mortar or concrete, and including any of the above-mentioned materials when they are fibre-reinforced. One type of interesting materials is constituted by the so-called DSP-materials, (DSP: Densified Systems containing ultrafine Particles), that is, materials based on densely packed particle systems with ultrafme particles homogeneously distributed between the densely packed fine particles, these materials typically being fibre-reinforced. Examples of such systems are disclosed, e.g., in US Patents Nos. 5,234,754 and 4,588,443. Examples of interesting extremely strong and tough structures (bodies) which can be made by combining these DSP systems, toughened with high concentrations of e.g. steel fibres, with high concentrations of main reinforcement are disclosed in US Patent No. 4923665. It should be mentioned that US Patent No. 4923665 discloses the application of a metal coating on DSP materials, e.g. by casting DSP materials against a metal layer such as a nickel layer formed by electrodeposition, and that International Patent Application Publication No. WO 82/01674 relates to a shaping tool made in this manner.

Said first body may be a reinforcing member and the spacing member may be positioned in contact with the reinforcing member. The second body may then be formed by casting a pourable, solidifiable material in contact with the spacing member. As an example, the first body may be made from steel or a steel alloy and the second body may be made from a hardened concrete or a DSP-material. The binding material may be selected such that maximum forces or stresses may be transferred between the first and second bodies or between the reinforcing members and the material of the body in which they are embedded even when the reinforcing members have relatively smooth outer surfaces. In case the materials of the first and second bodies have quite different characteristics, such as coefficient of elasticity, coefficient of thermal expansion, the material of the intermediate body may bridge such different characteristics and secure good bonds between the intermediate body and the first and second bodies, respectively. The principle of the invention thus can be used to provide a compensating interface between bodies of widely different characteristics, such as in the bonding of reinforcement to chemical bonded ceramics. As an example, the resiliency of the material of the intermediate body could be sufficient to accommodate a possible difference in coefficient of thermal expansion of the materials forming the first and second bodies, respectively. As another embodiment, the method according to the invention may be used for making a mould or tool part. In such case the first body may a layer having an outer surface with a desired shape and this layer may then form the active surface or working surface of the tool or mould part. The said layer may consist of or include a layer of metal for example formed by spray metal, vapour deposition or galvanic techniques, synthetic plastics material, or Gelcoat - ie a hard plastics layer formed by coating a curable resin onto a pattern previously coated with release agent. The second body which may be made by casting high strength concrete or DSP-material forms a body member or backing up member of the mould or tool part. The shaped metal layer may be made in different ways. As an example, a shaped metal layer may be made from a blank of sheet metal, such as stainless steel, which may be given the desired shape by punching and/or drawing. Alternatively, the shaped metal layer may be formed by galvanic or electrolytic precipitation on a surface of a sample having the shape desired. Thus, one of the first and second bodies may be formed from a substance in vapour form, such as by chemical vapour deposition, or by a substance in the form of ions in liquid phase, such as metal forming by galvanic technique.

A tool part thus made may be a drawing tool part for drawing a specific article from a sheet metal blank, and in such case the shaped metal layer may be precipitated on an outer surface part having a shape complementary to the desired shape of said specific article to be produced. The surface part on which the metal layer is formed by galvanic or electrolytic precipitation or vapour deposition is advantageously a surface part of a sample of the specific article to be produced, for example a spare part of a car body.

A mould part produced in a manner described above may, for example, be part of a mould for blow moulding, sheet moulding, resin transfer moulding, glass mat thermoplastics moulding, injection moulding, or vacuum moulding. Particular uses include as part of a blow mould for blow moulding plastic material, of an injection mould for moulding articles from plastics or metal, or as a compression mould for compressing a powdered or particulate material for forming an article therefrom. Such compression mould could be used for compressing and possibly sintering metallic particles or for forming and/or compressing concrete or a DSP-material so as to produce tiles, roof plates, or any other articles made from such materials, or other compressed powdered or particulate materials.

One or more passages for introducing liquid uncured binder into a cavity or cavities of the spacing member may be formed in first and/or the second body. In some cases one of the said first and second bodies is partly or completely surrounded by the other. This means that the space, which is defined between the first and second bodies and which contains the spacing member is not directly accessible. In such case, for example, one or more passages for introducing the liquid binder into the cavity or cavities of the spacing member may be formed in the outer one of the first or second bodies.

A spacing member having cavities for introduction of inactivated binder as discussed above may have a mesh or a chain mesh structure, or may be formed from non-woven fabrics. Examples include steel mesh, steel chain mesh, fiber mat such as glass fiber or carbon fiber mat, and non-woven fiber fabrics such as polypropylene or polyester fiber fabrics. Compression resistant spacing members such as those formed from steel chain mesh are advantageous for those applications where shrinkage of the spacing member during conversion to the intermediate binding body is to be resisted. Steel mesh or glass mats also have a degree of thickness- wise rigidity which helps minimise the effects of shrinkage. Non woven fabrics are advantageous where the intermediate binding layer is required to be compliant to small amounts of shear displacement between the first and second bodies. In general, the choice of spacing member structure will in part be dependent on the properties required of the finished bonded article. In some cases a spacing member consisting of one or more type of material may be preferred, for example a layer of mesh material with a layer of non- woven fabric abutting the second body.

As stated above, the binder at least partly forming the intermediate binding body may tend to shrink or expand when solidifying. When the mutual position of the first and second bodies cannot be adjusted to compensate, this tendency may endanger the efficiency of the bond being formed between the first and second bodies. In cases where the choice of a spacing member structure which resists shrinkage or expansion is inappropriate, in order to counteract shrinking of the binding body a super atmospheric pressure may be applied to the binder introduced in the cavity or cavities before the binder is solidified. Preferably, such super atmospheric pressure is maintained till the binder has solidified.

The liquid or gaseous binder or binder component may be supplied to a cavity or cavities of the spacing member in any known manner, for example by means of an external pressure source, such as a compressor, a pressure cylinder, or the like, or by sucking the binder into the cavity or cavities by reducing the ambient pressure in the vicinity of the spacing member (vacuum techniques). In the case of pressurised introduction of binder, to avoid substantially altering the mutual position of the first and second bodies, the bodies may be pressed together and against the spacing member by external forces. Alternatively, in the case of both pressure and vacuum induced introduction of binder, during or after introduction of the binder the first and second bodies may be separated slightly from their intended mutual position and maintained in this separated position, and after introduction of the binder the forces causing the separation may be released so that gravitational forces may apply an overpressure to the solidifying binder and return the bodies to their intended mutual position. Such separation of the first and second bodies may performed mechanically by applying external pulling forces, by means of wedges being inserted between the bodies etc. An oveφressure my also be applied to the solidifying binder by heating or cooling at least part of one of said first and second bodies temporarily while the binder is solidifying.

As another way of compensating for changes in the intended mutual position of the bodies during conversion of the spacing member to the intermediate binding body, pressure may be applied to the solidifying binder between the first and second bodies by pressurising components or devices arranged within or adjacent to the binder. Such components may comprise substances changing phase, such as from solid or liquid phase to gas phase. Alternatively, mechanical expandable devices may be included in or positioned in direct or indirect contact with the solidifying binder.

Still another way to secure that the mutual position of the first and second bodies is maintained and not changed by the pressurisation of the binder, is by using outer or inner back up members. The binding material is any substance capable of binding together the first and second bodies by contact with their opposed first and second surfaces. Strong glues and adhesives have been extensively researched an used in the building, automobile and aircraft industries. As a result, a wide range of binders is available from which to select one suitable for any given application of the present invention. The binder may therefore comprise any conventional curable binder or glue, including organic polymer based adhesives such as 2-component epoxys, polurethanes, acrylates/acrylamides, and also fuseable metals or metal alloys, brazing and soldering metals. The binder may contain reinforcing bodies such as fibers if desired.

The invention will now be further described with reference to the drawings, wherein Fig. 1 is a cross-sectional view of a conventional drawing tool comprising a pair of co-operating tool parts,

Fig. 2 is a cross-sectional view illustrating how a drawing tool part can be made by the method according to the invention,

Fig. 3 is a cross-sectional view showing adjacent structures of different materials, which could be interconnected by a strong bond by the method according to the invention,

Figs 4 and 5 are end views of structures made by the method according to the invention,

Fig. 6 is a fragmentary sectional view of a reinforced building structure made in accordance with the present invention, Figs. 7-10 diagrammatically illustrate various embodiments of the spacing member, Fig. 11 is a fragmentary sectional view illustrating how a liquid binder may be introduced into the space defined between the first and second bodies, Fig. 12 is a fragmentary sectional view of a cast or moulded body reinforced by metal reinforcing elements in accordance with the method according to the invention, Fig. 13 is a diagrammatic sectional view of mould parts used for making tiles or similar articles from a cement based material,

Fig. 14 is an axial sectional view illustrating casting of a test sample,and Fig. 15 is a sectional view corresponding to that shown in Fig. 14 and illustrating production of a slightly different test sample. Fig. 1 shows a pressing tool comprising upper and lower tool parts 10 and 11, respectively. Each tool part comprises a thin metal layer 12, such as a layer of nickel, e.g., of a thickness of 2-4 mm, which is fastened to and backed up by a body 13 of cast DSP material, such as that marketed under the trade mark DENSIT® by Densit A S, Aalborg, Denmark. The opposite surfaces of the metal layers are complementary shaped, and the pressing tool may be used for pressing a sheet metal blank 14 into a desired shape. As an example, the pressing tool may be used for making sheet metal spare parts, such as mudguards or the like, for cars.

Conventionally, each of the tool parts 10 and 11 are made as follows: The metal layer 12 is deposited by a galvanic process on a surface of a sample of the item to be produced. The body 13 is made by casting fibre reinforced DENSIT® against the exposed surface of the deposited metal layer 12. When the cast DSP material has solidified the body 13 is separated from the metal layer 12, and the metal layer is separated from the sample. Thereafter, the body 13 and the metal layer 12 are cleaned and subsequently a layer of binder is applied to the body 13, and the metal layer 12 is repositioned on and fastened to the body 12 by means of the binder.

Fig. 2 illustrates how a tool part 10 for a pressing tool as shown in Fig. 1 may be made by using the method according to the invention. The metal layer 12, such as a layer of nickel, is deposited by a galvanic process to a surface 15 of a model 16, which may be a sample of the item to be produced by the pressing tool. Thereafter, a thin spacing member 17 is arranged in close contact with the outer surface of the metal layer 12. The spacing member 17 may, for example, be made from a deformable, porous material, and as shown in Fig. 2 the spacing member 17 may contain reinforcing or anchoring members 18 extending transversely outwardly from the sheet-like spacing member. The body 13 of DSP material is now cast against the exposed outer surface of the spacing member 17, whereby the protruding end parts of the anchoring members 18 are embedded in the cast body 13. Finally, a binder, for example in the form of a liquid monomer, is introduced into the cavities or pores of the spacing member such that the binder is brought into intimate contact with the adjacent opposite surfaces of the metal layer 12 and the cast body 13, respectively. The binder is thereafter hardened or solidified, for example by thermally activated polymerisation of the liquid monomer. When the body 13 is being cast one or more passages 19 connecting the cavities or pores of the spacing member 17 with the surrounding atmosphere may be formed therein. Sush passage or passages may be used for introducing the liquid binder into the spacing member 17.

The spacing member 17 may alternatively be made from a solid material which may be removed from the space between the metal layer 12 and the body 13 when the latter has been cast and has solidified. The material of the spacing member may, for example, be partly or totally removed after having been melted or evaporated and the removed material is replaced by a binder. As another possibility, the spacing member 17 may be made from a solid binder, such as a thermoplastic material, which may be melted and thereby activated. As a further possibility, the porous spacing member 17 may at least partly be made from a binder component which is activated when a further gaseous or liquid binder component is introduced into the pores or cavities of the spacing member.

Fig. 3 illustrates more generally how a first structure 20 of one material, such as metal, may be strongly connected to a second structure 21 of another material, such as concrete or DSP material, which has been cast against the first structure. A relatively thin spacing member 17, which may be of any of the types described above, is arranged on and formed complementary to an outer surface of the first, prefabricated structure 20. Thereafter, the second structure 21 is cast against the exposed outer surface of the spacing member 17. When the cast material of the second structure has hardened or solidified a liquid or gaseous binder is introduced into the spacing member 17 and/or a binder component in the spacing member is activated in any other manner as previously described. A binder supply tube 22 extending between the spacing member 17 and an outer accessible surface part of the second structure 21 may be embedded in the second structure and may be used for introducing a binder component into the pores or cavities of the spacing member 17.

Figs. 4 and 5 show structures each comprising a central body 23 and a surrounding outer body 24. In Fig. 4 the inner body has a circular cross-section while in Fig. 5 it is provided with radially extending fins 25. The central body 23 may be made from plastic material, metal, metal alloy or any other solidified material. In order to make the structure a spacing member or layer 17, which may be of any of the types mentioned above, is applied to the outer surface of the central body 23. Thereafter the outer body 24 may be moulded or cast in situ around and against the spacing member 17. The outer member 24 is made from a material different from the material of the central member 23. As an example the outer member may be moulded or cast from concrete, DSP material, plastic material, metal or any other material which may be brought into a plastic or liquid state and be caused to solidify after moulding or casting. Finally, a binder or a component thereof is introduced into the space defined between the central and outer bodies in any of the manners described above. The spacing member 17 is preferably compressible so as to allow a possible contraction of the outer body 24 during solidification.

Alternatively, the structures shown in Figs. 4 and 5 could be made starting with the outer body 24. The spacing member could then be applied to the inner surface of the cavity defined therein. Thereafter, the central body 23 is made by moulding or casting a mouldable material in the cavity against the spacing member 17. In this case a contraction of the central body during solidification may cause a corresponding radial expansion of the spacing member 17.

Fig. 6 is a fragmentary sectional view of a building structure made from a basic material 26 of a type which may be moulded or cast, such as concrete or DSP material. The basic material may possibly contain reinforcing fibres of any type conventionally used in connection with concrete or DSP materials. The building structure further comprises reinforcing elements 27 forming part of a reinforcing structure. The reinforcing elements are preferably made from steel or another metal or metal alloy. In the embodiment shown the reinforcing elements are in the form of rods. Alternatively, they may be in the form of strands or wires. Such strands or wires could be made not only from metal, but also from fibres of carbon, plastic, or the like.

The characteristics of the basic material 26 and the material of the reinforcing elements 27 may be such that a strong durable bond between the basic material and the reinforcing elements can not be obtained when the basic material 26 is brought in direct contact with the reinforcing elements 27 when cast. However, by using the method according to the present invention it is possible to overcome this problem. Thus, according to this method the structure illustrated in Fig. 6 is made as follows: A spacing member or layer 17 of any of the types previously described is applied to the outer surface of each reinforcing element 27 and a reinforcing structure is made by such elements. Thereafter, the basic material 26 is cast or moulded around the reinforcing structure with the spacing layers 17 so as to embed the reinforcing structure in the poured basic material 26. The basic material is now allowed to solidify, and thereafter a binder is introduced into the space defined by the spacing layer 17 and/or a binder component present in the spacing layer is activated as described in the present specification. The binder may be chosen such that a strong, force transmitting bond is obtained between the basic material 26 and the reinforcing elements 27. Furthermore, the binder may be sufficiently elastic to compensate for differences in thermal expansion, etc. of the basic material 26 and the material of the reinforcing elements 27.

The spacing member or spacing layer 17 may comprise anchoring members 18 of metal or another solid material as shown in Fig. 2 whereby also a mechanical interconnection of the adjacent bodies may be obtained. As mentioned above, the spacing member may be porous and/or hollow and be adapted to receive a binder or a component thereof in its pores or cavities and/or it may be adapted to be removed totally or partly before the binder or binder component is introduced. Furthermore, the spacing member may contain one or more binder components for reacting with the binder component or components being introduced. Another possibility is that the binder is fully contained in or forms the spacing member 17.

Figs. 7-10 illustrate first and second bodies 28 and 29, respectively, one of which has been cast or moulded against an intermediate spacing member or layer 17 in accordance with the teachings of the present invention. In Figs. 7-10 the spacing layer 17 contains all the components of the binder by means of which the bodies 28 and 29 are to be interconnected.

In Fig. 7 the spacing member 17 is a single layer of homogeneous binder material which may be activated, for example by heating and melting, when one of the bodies 28 and 29 has been cast against the solid layer 17 and has solidified. Fig. 8 differs from Fig. 7 by the fact that one end of anchoring members 30 is embedded in the spacing layer 17 while the other end of the anchoring members extends transversely therefrom. When the second body 29 is cast against the spacing layer 17 covering the adjacent surface of the first body 28 the protruding ends of the anchoring members are embedded in the second body as illustrated.

Figs. 9 and 10 show structures corresponding to the structure shown in Fig. 7 apart from the fact that in Figs. 9 and 10 the spacing layer 17 is divided into two and three sub layers, respectively. Each of these sub layers may contain a binder component. When the spacing layer 17 is activated and melted the various components are intermixed and may react with each other.

Fig. 11 is a fragmentary sectional view corresponding to those shown in Figs. 7-10. In Fig. 11 inlet passages 31 and 32 are formed in the body 28 and the inner end of the passage 32 forms an inlet manifold 33. Each of these passages interconnects the space defined between the bodies 28 and 29 by the spacing member 17 with external binder pressurising means, not shown. The spacing member 17 may include a binder or the binder may be introduced in a porous or hollow spacing member as explained above. In any case, when the binder has been activated and or introduced into the space between the bodies 28 and 29 binder under pressure or another pressurised medium, such as liquid or gas, may be applied to the passages 31 and 32 while the binder is solidifying as indicated by arrows 34 in Fig. 11.

The structure shown in Fig. 12 corresponds to that shown in Fig. 6 comprising a moulded or cast basic material 26 and a rod-shaped reinforcing element 27, which is surrounded by the spacing member 17. In the structure shown in Fig. 12 the reinforcing element 27 and the surrounding spacing member 17 is encircled by a spiral reinforcing member 35 which is embedded in the basic material 26. The binder, which is included in or injected into the spacing member 17, may be pressurised while solidifying as explained above. The spiral member 35 may then function as a back-up member for taking up forces provided thereby, so as to counteract formation of cracks or disintegration of the basic material 26 around the spacing member 17.

Fig. 13 illustrates mould parts made in accordance with the method of the present invention and for use in forming tiles. A mould part 36 comprises a body member or back up member 37 cast from a DSP material and a metal layer 38 connected to the upper surface of the back up member 37. The metal layer may be drawn from sheet metal, such as stainless steel, or may be made by galvanic or electrolytic precipitation as described above. When the mould part is to be used for forming a tile or a similar article it is placed on top of a supporting body 39 having an upper surface, which is complementary to the lower surface of the mould part 36, and a plane bottom surface. The assembly formed by the supporting body 39 and the mould part 36 may then be arranged on a table 40 of a compacting apparatus, not shown. The supporting body 39 may have been made in the same manner as the mould part 36. Thus, it may comprise an upper metal layer 41 , which is bonded to a base member 42 made from for example cast DSP material.

Now, a metered amount of concrete or another cement based material, for example an extruded length of the material, may be dispensed onto the upper surface of the mould part 36 and an upper mould part, not shown, may be moved into engagement with the lower mould part 36 so as to define a mould cavity in which the concrete is compressed or compacted and possibly exposed to vibrations. When the concrete or cement based material has been compacted so as to form a "green" tile 43 or another article the mould may be opened and the mould part 36 with the green tile may be removed from the compacting apparatus and passed to a curing area. Thereafter, a new mould part may be arranged on top of the supporting body 39 on the table 40 of the compacting apparatus.

Example 1

A composite body was made in accordance with the present invention in the following manner. A plane, circular nickel shell 50 with a diameter of 100 mm and a thickness of 2 mm was electro formed on a plane mandrel surface. The nickel shell 50 thus formed was placed on the bottom plate 51 of a mould as shown in Fig. 14. A layer of a steel wire mesh 52 with a mesh size of 2 mm and a wire diameter of 0.5 mm was arranged on the upper surface of the bottom 51 and a textile filter 53 of non-woven polyethylene fibres and with a thickness of 0.2 mm was placed on top of the wire mesh 52. The peripheral edges of the nickel shell 50 and the superposed layers 52 and 53 were clamped between the mould bottom plate 51 and the bottom edge of a cylindrical mould wall 54 by means of connecting screws 55 extending through openings in radial outer lugs 56 welded to the outer peripheral surface of the mould wall 54. A mortar was made from Densit ToolCast marketed by Densit -A/S, Aalborg, Denmark (Densit ToolCast is a Portland cement-based DSP material to which, during mixing, is added 4.5 % w/w steel fibres of diameter 0.4 mm, length 12.5 mm, tensile strength 1200 MPa). The mortar was poured into the mould and a steel rod 57 was arranged axially therein so that one end portion thereof dipped into the mortar while the other end portion of the rod extended upwardly from the mortar. The textile filter 53 prevented the mortar from penetrating into the wire mesh 52. Thereafter the mould with the mortar was vibrated and cured/hardened so as to form a solid body 58. After hardening of the mortar a resin based epoxy adhesive marketed under the trade name Araldite® 2019 by Ciba Speciality Chemicals Pic was injected into the wire mesh 52 and into the textile filter 53 through central openings 63, which were formed in the bottom plate 51 and in the nickel shell 50, by means of a manually operated mixing pump adapted to mix the two components of the adhesive. The injection pressure was about 0.5 bar. Araldite® 2019 is a relatively low viscosity (3 Pas) adhesive described in greater detail in a brochure "Industrial Range Araldite, Publication No. A418a-GB 3000/08/992 W&B, published by Ciba Speciality Chemicals PLC 1998.

It was found that the adhesive filled the spacing member and penetrated the textile and created bonding between the solid mortar body and the nickel shell.

Example 2

A composite body or test sample similar to that described in example 1 was made in a mould as illustrated in Fig. 15. The nickel shell 50 and the wire mesh 52 were the same as described in example 1. This time, however, no textile filter was used. The nickel shell 50 was placed on top of the mould bottom plate 51, and a 0.5 mm thick layer of adhesive was applied directly to the upper surface of the shell 50. The adhesive was of the type marketed under the trade name DanikumLim 6233 by Frede Andersens Fabriker A/S, Lille Skensved, Denmark, a polystyrene acrylate aqueous dispersion adhesive suitable for "wet in wet" application. The wire mesh 52 was placed on top of the adhesive layer and pressed into contact with the nickel shell 50 by means of the screws 55 as described above in example 1. The ceramic body 58 was cast on top of the wire mesh 52 in the same manner as described in example 1.

Also in this case it was found that the adhesive filled the spacing member and created bonding between the solid mortar body and the nickel shell.

Claims

1. A method of forming a composite body comprising a pair of first and second solid bodies and an intermediate body binding the first and second bodies together, said method comprising arranging a spacing member defining the outer surfaces of the intermediate binding body such that a first surface part of the spacing member is in engagement with an adjacent surface of the first body, forming the second body in a deformable condition against and in contact with a second surface part of the spacing member opposite to said first surface part, solidifying said second body, and converting the spacing member into said intermediate binding body while maintaining the first and second bodies in their mutual position.

2. A method according to claim 1, comprising forming said first solid body, arranging a spacing member defining the outer surfaces of the intermediate binding body such that a first surface part of the spacing member is in engagement with an adjacent surface of the first body, forming the second body in a deformable condition against and in contact with a second surface part of the spacing member opposite to said first surface part, solidifying said second body, and converting the spacing member into said intermediate binding body while maintaining the first and second bodies in their mutual position.

3. A method according to claim 1 or 2, wherein the spacing member comprises an inactivated or not yet active binding material, the conversion of the spacing member including activating said binding material or allowing it to activate so as to bind the first and second bodies together by the binding material.

4. A method according to claim 3, wherein the binding material is activated by exposing it to radiation, heat, a solvent and/or another binder component.

5. A method according to any of the claims 1-4, wherein the spacing member defines one or more inner cavities therein, a binder component or a binder in a gaseous or fluid state being introduced into said cavities, such that said binder component or binder is caused to come into contact with said opposite first and second surface parts of the spacing member and the adjacent surface parts of said first and second bodies engaging therewith, and the binder is subsequently solidified.

6. A method according to claim 4 wherein the spacing member comprises one or more materials selected from fiber mat, metal mesh, polymer mesh and porous bonded particulate material.

7. A method according to claim 5 or 6, wherein the spacing member defines a porous matrix structure, the binder component or binder being introduced into the porous structure so as to be brought into contact with the surface parts of the first and second bodies being in engagement with the opposite first and second surface parts of the spacing member, respectively.

8. A method according to any of the claims 5-7, wherein the spacing member includes one or more components reacting chemically with the binder or binder component being introduced.

9. A method according to any of the claims 1-8, wherein said first body is a reinforcing member, the spacing member being positioned in contact with the reinforcing member and the second body being formed by casting a pourable, solidifiable material in contact with the spacing member.

10. A method according to claim 9, wherein the first body is made from steel or a steel alloy, the second body being made from a ceramic.

11. A method according to claim 10, wherein the ceramic is a chemically bonded ceramic.

12. A method according to claim 11, wherein the chemically bonded ceramic is a cement-based paste, mortar or concrete.

13. A method according to any of claims 9-12, wherein the second body is made from or comprises a DSP-material.

14. A method according to any of claims 1-8, wherein the second body is made from or a metal.

15. A method according to claim 14, wherein the metal is selected from aluminium, copper, and iron.

14. A method according to any of the claims 1-13, wherein the resiliency of the material of the intermediate body is sufficient to accommodate a possible difference in coefficient of thermal expansion of the materials forming the first and second bodies, respectively.

15. A method according to any of the claims 1-14 for making a mould or tool part wherein the first body is a layer of metal , synthetic plastics material, or Gelcoat having an outer surface with a desired shape, the second body being made by casting high strength concrete.

16. A method according to claim 15, wherein the high strength concrete is a DSP-material.

17. A method according to claim 15 or 16, wherein the metal layer is a layer of shaped sheet metal, such as stainless steel.

18. A method according to claim 11, wherein the metal layer has been or is formed by galvanic or electrolytic precipitation or vapour deposition on a surface of a sample having the shape desired.

19. A method according to claim 18, wherein the mould or tool part made is for drawing a specific article from a sheet metal blank, the shaped metal layer being precipitated on an outer surface having a shape complementary to the desired shape of said specific article to be produced.

20. A method according to any of claims 15-18, wherein the mould or tool part is a mould or tool part for injection moulding.

21. A method according to any of claims 15-18, wherein the mould or tool part is a mould or tool part for casting.

22. A method according to any of claims 15-18, wherein the mould or tool part is a mould or tool part for forging.

23. A method according to any of claims 15-18, wherein the mould or tool part is a mould or tool part for punching or stamping.

24. A method according to any of the claims 11-14, wherein the mould or tool part produced is for compressing a powdered or particulate material for forming an article therefrom.

25. A method according to any of the claims 5-24, wherein one or more passages for introducing the fluid binder or binder component into the cavity or cavities of the spacing member is/are formed in the first and/or second body or bodies.

26. A method according to any of the claims 5-25, wherein a super atmospheric pressure is applied to the binder introduced in the cavity or cavities before the binder is solidified.

27. A method according to claim 26, wherein the super atmospheric pressure is maintained till the binder has solidified.

28. A method according to any of the claims 5-27, wherein a sub atmospheric pressure is applied to the cavity or cavities to facilitate introduction of the binder or binder component into the cavity or cavities before the binder is solidified.