COMPOSITE MATERIAL WITH IMPROVED SHAPING PROPERTIES AND METHOD FOR PRODUCING SUCH A COMPOSITE MATERIAL AND A SHAPED COMPONENT FROM IT

Abstract

A composite material includes a metallic bottom flat element, a metallic top flat element, and an intermediate layer made of a thermosetting synthetic material and arranged between the bottom flat element and the top flat element. The intermediate layer includes three or more duromers, with at least one of the duromers being in a cured state and the other ones of the duromers being in an uncured state. The at least one of the duromers has a polymerization temperature between 50 and 100 C., with a second one of the other ones of the duromers having a polymerization temperature between 170 and 220 C. and a third one of the other ones of the duromers having a polymerization temperature between 230 and 260 C.

Claims

1.-17. (canceled)

18. A composite material, comprising: a metallic bottom flat element; a metallic top flat element; and an intermediate layer made of a thermosetting synthetic material and arranged between the bottom flat element and the top flat element, said intermediate layer comprising three or more duromers, with at least one of the duromers being in a cured state and the other ones of the duromers being in an uncured state, said at least one of the duromers having a polymerization temperature between 50 and 100 C., with a second one of the other ones of the duromers having a polymerization temperature between 170 and 220 C. and a third one of the other ones of the duromers having a polymerization temperature between 230 and 260 C.

19. The composite material of claim 18, wherein, as seen in plan view, the bottom flat element and the top flat element have same outer dimensions and are flush with each other.

20. The composite material of claim 18, wherein the intermediate layer includes polymers of a same element group or polymers of different element groups of different polymerization temperatures.

21. The composite material of claim 20, wherein the same element group includes polyurethanes or epoxides.

22. The composite material of claim 18, wherein the duromers have different polymerization temperatures or polymerize using different polymerization mechanisms.

23. The composite material of claim 22, wherein a difference in the polymerization temperatures of individual ones of the duromers is at least 10 C., preferably at least 40 C.

24. A composite material, comprising: a metallic bottom flat element; a top flat element configured to cover only a part of the bottom flat element as seen in plan view; and an intermediate layer made of thermosefting synthetic material and arranged between the bottom flat element and the top flat element.

25. The composite material of claim 24, wherein the intermediate layer comprises three or more duromers, at least one of the duromers being in a cured state and the other ones of the duromers being in an uncured state,

26. The composite material of claim 25, wherein the at least one of the duromers has a polymerization temperature between 50 and 100 C., with a second one of the other ones of the duromers having a polymerization temperature between 170 and 240 C. and a third one of the other ones of the duromers having a polymerization temperature between 230 and 260 C.

27. The composite material of claim 24, wherein the top flat element is made of synthetic material or metal.

28. The composite material of claim 25, wherein the duromers have different polymerization temperatures or polymerize using different polymerization mechanisms.

29. The composite material of claim 28, wherein a difference in the polymerization temperatures of individual ones of the duromers is at least 10 C., preferably at least 40 C.

30. The composite material of claim 24, wherein the intermediate layer includes polymers of a same element group or polymers of different element groups of different polymerization temperatures.

31. The composite material of claim 30, wherein the same eluent group includes polyurethanes or epoxides.

32. A method for producing a composite material in the form of a strip or panel, comprising; applying an intermediate layer of three or more duromers having different polymerization temperatures onto a metallic bottom flat element; and placing a top flat element on the intermediate layer such as to produce an integrally bonded composite between the bottom flat element and the top flat element and the intermediate layer under the influence of force and/or temperature, wherein only one of the duromers undergoes curing during production of the composite material

33. The method of claim 32, wherein the one of the duromers is cured at a temperature of 30 to 130 C.

34. The method of claim 32, wherein the one of the duromers is cured at a, temperature of 50 to 100 C.,

35. The method of claim 32, wherein the duromers are applied to the bottom flat element as a film or prepreg or by extrusion.

36. The method of claim 32, wherein the duromers are applied to the bottom flat element as a mixture or arranged separately.

37. A method, comprising: applying an intermediate layer of three or more duromers having different polymerization temperatures onto a metallic bottom flat element; placing a top flat element on the intermediate layer such as to produce an integrally bonded composite between the bottom flat element and the top flat element and the intermediate layer under the influence of force and/or temperature and thereby produce a composite material, wherein only a first one of the duromers undergoes curing during production of the composite material; forming the composite material into a component; subjecting the component to a heat treatment and curing at least a second one of the duromers, which has not yet cured, under the influence of temperature.

38. The method of claim 37, wherein the second one of the duromers is cured at a temperature of 150 to 240 C.

39. The method of claim 37, wherein the second one of the duromers is cured at a temperature of 170 to 220 C.

40. The method of claim 37, further comprising: heat-treating the composite material that is formed into the component; and curing a third one of the duromers, which has not yet cured, under the influence of temperature for repairing the component by re-establishing a connection of the metallic bottom flat element (2) and the top flat element

Description

[0044] The invention will be described hereinafter using the example of duromers which have different polymerization temperatures.

[0045] The composite material is made e.g. of two galvanized steel sheets, between which there is a polymer core as an intermediate layer comprised of three or more duromers having different polymerization temperatures.

[0046] When producing the composite material 1, the first duromer 3 cures at relatively low temperatures (e.g. 50-100 C.) whilst the polymerization of the duromers 4 and 5 does not yet commence at this temperature or is only very slight.

[0047] Owing to the curing of duromer 3, the distance between the two flat elements 2, 2 in the composite material 1 is defined such that a semi-finished product is produced, in which duromer 4 of the intermediate layer completely cures only after forming into a component under the influence of temperature at e.g. 170 to 200 C. as in the case of cathodic dip coating.

[0048] This semi-finished product can thus be further processed, similar to a monolytic sheet, to form the component by forming. The duromer 3, which is already cured in the semi-finished product, ensures that the distance between the two flat elements 2, 2 is maintained, even during forming into a component. By suitably applying duromer 3, e.g. in the edge regions of the composite material 1, and duromer 4 in the inner surface region, duromer 4 is not pressed out of the intermediate space and thus cannot contaminate the forming tool. Subsequent to the forming step, duromer 4 is cured in a further heat-treatment step under the influence of temperature and the required component properties are thus achieved.

[0049] When producing the composite material 1, the distance between the two flat elements 2, 2 can be advantageously set via the design, in accordance with the invention, of the composite material 1 such that contacting of the two flat elements 2, 2 owing to high forming forces does not occur, or only occurs in previously defined regions. The loss of properties such as vibration damping, heat insulation, stiffness, etc. is thus prevented.

[0050] In the design, in accordance with the invention, of the composite material 1, the intermediate layer of the composite material additionally has a further proportion of a third duromer having an even higher polymerization temperature. Should the component become damaged during use (e.g. delamination between flat elements 2, 2 and duromer core 3, 4), the polymerization of the third duromer is then advantageously used for repairing the component and the required component properties are thus reproduced. The connection between the bottom flat element 2 and top flat element 2 is thus re-established after a possible delamination of the bottom flat element 2 and/or top flat element 2 from the duromers 3, 4, 5.

[0051] During further processing of the composite material 1 to form a component, it is advantageous if the difference in the polymerization temperatures of the respective duromers 3, 4, 5 is at least 10 C. A difference of at least 40 C. has proved to be particularly advantageous.

[0052] Epoxides, polyurethanes or other thermosetting plastics can be used for example as duromers 3, 4, 5 for the composite material 1 in accordance with the invention and permit considerably better bonding to the metallic top layers than is possible with unmodified thermoplastics.

[0053] The composite material in accordance with the invention can thus be formed without any problems and without any tool contamination, wherein the required component properties can be achieved in a process-reliable manner.

[0054] Owing to the thermosetting polymer core, the resulting component has a considerably higher stiffness than would be achieved with a comparable thermoplastic, with the same thickness.

[0055] Against the background that a single, partially cured duromer is not used for producing the composite material but instead three or more duromers are used, of which at least one is uncured and the others are cured, the properties of the composite material in accordance with the invention and of the component produced by forming can additionally be set in a considerably more precise manner which has a positive effect on the process reliability during production. In addition, the reactivity of the polymeric core layer is considerably higher owing to the fact that partial curing has not occurred.

[0056] Epoxides, polyurethanes or other suitable duromers can be used as the duromers. Consequently, in accordance with the invention the same or different duromers having different polymerization start conditions can be used for the intermediate layer, said conditions differing e.g. in terms of the polymerization temperature.

[0057] The basic requirement is that the duromers effectively bind to the metallic bottom flat elements and/or top flat elements made from metal or synthetic material, and the polymerization temperatures thereof are sufficiently far apart. Three or more duromers are used, the polymerization thereof being triggered in different manners (e.g. thermal polymerization versus catalytic polymerization).

[0058] The disadvantages when producing a component in accordance with the prior art can thus be overcome in a simple manner using this innovative composite material and the production method in accordance with the invention.

LIST OF REFERENCE SIGNS

[0059] 1 Composite material [0060] 2 Bottom flat element [0061] 2 Top flat element [0062] 3 Duromer [0063] 4 Duromer [0064] 5 Duromer [0065] 6 Patch