Insulating element

Abstract

An insulating material for insulating a structural element in a vehicle including a support element with a first surface and a second surface, and an expandable material which is arranged on the support element. The expandable material is arranged here on a first sub-region of the first surface of the support element, and a second sub-region of the first surface is free from expandable material. The first sub-region is configured here in such a manner that the first surface of the support element is completely covered with expanded material after expansion of the expandable material.

Claims

1. An insulating element for insulating a structural element in a vehicle, said insulating element comprising: a carrier element having a first surface and a second surface; and an expandable material which is disposed on the carrier element; wherein: (i) the first surface of the carrier element includes a first part-region that is defined where the expandable material is disposed on the first surface and a second part-region that is free of expandable material, (ii) the first-part region is composed of a plurality of non-contiguous elements including (a) a first element that is disposed in a strip-shaped manner along the circumference of the first surface, and (b) a plurality of further elements that are disposed in an internal region of the first surface, are interconnected prior to the expansion of the expandable material, and are non-contiguous with the first element, and (iii) the insulating element is configured so that the first surface of the carrier element is completely covered by expandable material after an expansion of the expandable material.

2. The insulating element as claimed in claim 1, wherein the first part-region is between 10 and 80% of the first surface.

3. The insulating element as claimed in claim 1, wherein a ratio of a mass of the expandable material to a size of the first surface is between 0.15 and 0.75 g/cm.sup.2.

4. The insulating element as claimed in claim 1, wherein a width of the carrier element is more than 50 mm, and wherein a length of the carrier element is likewise more than 50 mm.

5. The insulating element as claimed in claim 1, wherein the plurality of further elements forms a pattern that has strip-shaped elements.

6. The insulating element as claimed in claim 1, wherein the plurality of further elements includes a second strip-shaped element that extends transversely across the internal region.

7. The insulating element as claimed in claim 6, wherein the second strip-shaped element has a rectangular or V-shaped or semi-circular cross section.

8. The insulating element as claimed in claim 6, wherein the second strip-shaped element is disposed in a depression of the carrier element.

9. The insulating element as claimed in claim 1, wherein the plurality of further elements are distributed in a regular pattern across the first surface.

10. A system having a structural element and an insulating element as claimed in claim 1 disposed therein.

11. The insulating element as claimed in claim 1, wherein the first element surrounds the plurality of further elements.

12. The insulating element as claimed in claim 1, wherein the first element extends along an entire circumference of the first surface.

13. The insulating element as claimed in claim 1, wherein the expandable material has an expansion rate of 300 to 3000%.

Description

(1) Details and advantages of the invention are described in the following text on the basis of exemplary embodiments and with reference to schematic drawings, in which:

(2) FIG. 1 shows an exemplary illustration of a body according to the prior art;

(3) FIGS. 2a and 2b show schematic illustrations for explaining an exemplary insulating element according to the prior art;

(4) FIGS. 3a to 3h show schematic illustrations of a first surface of the carrier element having a first and a second part-region;

(5) FIGS. 4a and 4b show schematic illustrations of an exemplary insulating element in a structural element; and

(6) FIGS. 5a and 5b show schematic illustrations of an exemplary insulating element in a structural element.

(7) In FIGS. 3a to 3h in each case a plan view of an exemplary insulating element 16 is illustrated such that only the first surface of the carrier element 11 is visible. Said first surface of the carrier element 11 herein comprises a first part-region 18 on which expandable material is disposed, and a second part-region 19 which is free of expandable material. The first part-region 18 and the second part-region 19 herein can form one contiguous face or else a plurality of non-contiguous faces. In all exemplary embodiments according to FIGS. 3a to 3h the first-part region 18 and the second part-region 19 are in each case disposed such that after an expansion of the expandable material the first surface of the carrier element 11 is completely covered with expandable material. This is achieved in particular in that the second part-regions, or the second part-region, respectively, does not exceed specific critical dimensions. For example, the second part-region 19, or the second part-regions 19, respectively, can be chosen in such a manner that a width of said second part-regions 19, or of said second part-region 19, respectively, does not exceed a specific dimension. The expandable material which is disposed on the adjacent first part-regions 18 can thus bridge the second part-regions 19 when expanded.

(8) There are various design embodiments of the part-regions 18, 19 in the embodiments illustrated in an exemplary manner. On the one hand, the first part-region 18 can be configured as a contiguous pattern, for example, as is the case in FIGS. 3a, 3b, and 3c. In other exemplary embodiments the first part-region 18 is composed of a plurality of non-contiguous elements, as is illustrated in FIGS. 3d to 3h.

(9) Furthermore, the first part-region 18 can have one or a plurality of strip-shaped elements. This is depicted in an exemplary manner in FIGS. 3a, 3b, 3c, 3d, 3e, and 3g. A first strip-shaped element herein can be disposed along the circumference of the first surface of the carrier element 11, as is shown in FIGS. 3a to 3e. However, the first part-region 18 can also be disposed on the carrier element 11 in another manner, as is depicted in FIGS. 3f and 3h.

(10) In some exemplary embodiments the first part-region 18 is distributed as a regular pattern across the first surface of the carrier element 11. This is the case in images 3f to 3h.

(11) As can be seen from the exemplary embodiments illustrated, the most varied of arrangements of the first part-region 18 and of the second part-region 19 on the first surface of the carrier element 11 are possible. It is essential herein that after an expansion of the expandable material which is disposed on the first part-region 18, the first surface of the carrier element 11 is completely covered with expandable material.

(12) The carrier element 11 of the insulating material 16 herein has a width 27 and a length 26. Both the width 27 as well as the length 26 of the carrier element are more than 50 mm in the exemplary embodiments according to FIGS. 3a to 3h.

(13) A cross section of the insulating element 16 from FIG. 3d is illustrated in FIGS. 4a and 4b. FIG. 4a herein shows the insulating element 16 prior to an expansion of the expandable material 13, and FIG. 4b shows an insulating element 16 after expansion of the expandable material 13, thus the expanded material 13.

(14) In the exemplary embodiment according to FIGS. 4a and 4b the carrier element 11 has a peripheral region 21 which is designed so as to be slightly offset in relation to an internal region of the carrier 11. The peripheral region 21 herein can be configured so as to be integral to the carrier element 11 (not illustrated) or so as not to be integral, as is illustrated in FIGS. 4a and 4b. The expandable material 13 is disposed in a strip-shaped manner on said peripheral region 21, wherein said expandable material 13 is disposed along a circumference of the first surface 23 of the carrier element 11. Moreover, on the carrier element 11 further strip-shaped elements of expandable material 13 are disposed on first part-regions of the first surface 23 of the carrier element 11. Said further strip-shaped elements in this exemplary embodiment are disposed in depressions of the carrier element 11. The further strip-shaped elements herein have a V-shaped cross section.

(15) The insulating element 16 in the structural element 12, 14 is illustrated after expansion in FIG. 4b. It can be seen herein that the expanded material 13 completely covers the first surface 23 of the carrier element 11. Moreover, the expanded material 13 bridges the gap, which existed prior to the expansion, between the insulating element 16 and the structural element 12, 14. On account thereof, the insulating element 16 is locally fastened in the structural element 12, 14. On account of the complete coverage of the first surface 23 of the carrier element 11, the entire cross section of the structural element 12, 14 is filled with expanded material 13. An improved acoustic insulating performance of the insulating element 16 is achieved on account thereof.

(16) A further exemplary embodiment of an insulating element 16 in a structural element 12, 14 is illustrated prior to and after expansion of the expandable material 13 in FIGS. 5a and 5b. The carrier element 11 again has a first surface 23 and a second surface 24. There are first part-regions which are covered with expandable material 13 on the first surface 23. Moreover, there are second part-regions which are free of expandable material 13. The carrier 11 in this exemplary embodiment does not have any offset peripheral regions 21. The insulating element 16 illustrated here corresponds to the insulating element 16 that is shown in a plan view in FIG. 3a. In a manner similar to the insulating element 16 in FIGS. 4a and 4b, the first part-region is disposed here too by way of a first strip-shaped element along a circumference of the first surface of the carrier element 11. Moreover, there is a second strip-shaped element which is disposed transversely across an internal region of the first surface 23 of the carrier element 11.

(17) After the expansion of the expandable material 13, the first surface 23 of the carrier element 11 is completely covered with expandable material 13. Again, a gap between the insulating element 16 and the structural element 12, 14 is closed by expanded material 13. The expanded material 13 also in this exemplary embodiment thus completely covers a cross section of the structural element 12, 14, on account of which improved acoustic insulation properties result.

(18) Expandable Materials (Capable of Foaming)

(19) In principle, any arbitrary material that can be made to foam in a controlled manner can be used as the expandable material. Said material herein may or may not have reinforcing properties. The material capable of foaming is typically foamed in a thermal manner, by moisture, or by electromagnetic radiation.

(20) Such an expandable material typically has a chemical or physical propellant. Chemical propellants are organic or inorganic compounds which decompose under the influence of temperature, moisture, or electromagnetic radiation, wherein at least one of the decomposition products is a gas. Compounds which transition into the gaseous aggregate state when the temperature is increased can be used as physical propellants, for example. On account thereof, both chemical as well as physical propellants are capable of generating foam structures in polymers.

(21) The expandable material is preferably foamed in a thermal manner, wherein chemical propellants are used. Azodicarbonamides, sulfo hydrazides, hydrogen carbonates, or carbonates are suitable as chemical propellants, for example.

(22) For example, suitable propellants are also commercially available under the Expancel brand from Akzo Nobel, Netherlands, or under the Celogen brand from Chemtura Corp., USA.

(23) The heat required for foaming can be introduced by way of external or by way of internal heat sources such as an exothermal chemical reaction. The material capable of foaming is preferably capable of being foamed at a temperature of 200 C., in particular of 140 C. to 190 C., preferably of 160 C. to 180 C.

(24) Single-component epoxy resin systems which are not free-flowing at room temperature and in particular have an enhanced impact resistance and contain thixotropy agents such as aerosols or nanoclays are suitable as expandable materials, for example. For example, epoxy resin systems of this type comprise 20 to 50% by weight of a liquid epoxy resin, 0 to 30% by weight of a solid epoxy resin, 5 to 30% by weight of viscosity modifiers, 1 to 5% by weight of physical or chemical propellants, 10 to 40% by weight of fillers, 1 to 10% by weight of thixotropy agents, and 2 to 10% by weight of heat-activatable curing agents. Reactive liquid rubbers based on nitrile rubber, or derivates of polyether polyol polyurethanes, core shell polymers, and similar systems known to a person skilled in the art are suitable as viscosity modifiers.

(25) Single-component polyurethane compositions, constructed from crystalline polyesters comprising OH groups mixed with further polyols, preferably polyether polyols, and polyisocyanates with blocking isocyanate groups, that include propellants are likewise suitable expandable materials. The melting point of the crystalline polyester should be 50 C. The isocyanate groups of the polyisocyanate can be blocked by nucleophiles such as caprolactam, phenols, or benzoxalones, for example. Blocked polysiocyanates such as are used, for example, in powder-coating technology and are commercially available from Degussa GmbH, Germany, for example under the Vestagon BF 1350 and Vestagon BF 1540 brands are furthermore suitable. So-called encapsulated or surface-deactivated polyisocyanates which are known to a person skilled in the art and are described, for example, in EP 0 204 970 are likewise as isocyanates.

(26) Two-component epoxy/polyurethane compositions containing propellants such as are described, for example, in WO 2005/080524 A1 are furthermore suitable as expandable materials.

(27) Ethylene vinyl acetate compositions containing propellants are furthermore suitable as expandable materials.

(28) Expandable materials that are likewise suitable are marketed by Sika Corp., USA under the SikaBaffle 240, SikaBaffle 250 or SikaBaffle 255 brand and are described in the U.S. Pat. Nos. 5,266,133 and 5,373,027.

(29) Furthermore suitable expandable materials are marketed by Sika under the SikaBaffle-450, SikaBaffle-420, SikaBaffle-250NT, SikaBaffle-255 and SikaBaffle-250PB2 brands. Such expandable materials have an expansion rate of approximately 300 to 3000% and are particularly preferable for the present invention.

(30) In particular SikaBaffle-450, having an expansion rate of more than 1200%, is suitable for the purposes of the present invention, because the second part-region of the first surface in the expansion of the expandable material is reliably covered on account of a high expansion rate.

(31) In one concrete preferred exemplary embodiment, an arrangement of the expandable material on the carrier element according to FIG. 3a is embodied at a ratio of a mass of the expandable material to a size of the first surface of approximately 2.5 g/cm.sup.2. The expandable material herein under the influence of heat at 180 C. over 30 min has an expansion rate of approximately 2000%. On account thereof, a complete coverage of the first surface with expanded material can be achieved, the described advantages of the invention in terms of acoustic insulation resulting therefrom.

(32) For example, expandable materials having reinforcing properties which are marketed under the brand SikaReinforcer 941 by Sika Corp., USA, are preferred as expandable materials having reinforcing properties. The latter are described in U.S. Pat. No. 6,387,470.

(33) Carrier Material

(34) The carrier material can be composed of arbitrary materials. Preferred materials are plastics materials, in particular polyurethanes, polyamides, polyesters, and polyolefins, preferably high-temperature-resistant polymers such as poly(phenylene ether), polysulfones, or polyether sulfones, which are in particular also foamed; metals, in particular aluminum and steel; or grown organic materials, in particular wood or other (densified) fibrous materials, or glass-type or ceramic materials; especially also foamed materials of this type; or arbitrary combinations of said materials. Polyamide, in particular polyamide 6, polyamide 6.6, polyamide 11, polyamide 12, or a mixture thereof, is particularly preferably used. Combinations with fibers such as, for example, glass fibers or carbon fibers, are also possible.

(35) The carrier element can furthermore have an arbitrary construction and an arbitrary structure. Said carrier element can be for example solid, hollow, or foamed, or have a grid structure. The surface of the carrier element can typically be smooth, rough, or structured.

(36) In the case of sealing and reinforcement elements according to the invention in which the expandable material is located on a carrier element, the production method differs according to whether the carrier element is or is not composed of a material that is capable of being processed by injection molding. In the affirmative, a two-component injection molding method is usually used. Herein a first component, in this case the carrier element, is injected first. After the solidification of said first component, the cavity in the tool is enlarged or adapted, respectively, or the injection-molded product is laid up in a new tool, and the first component is overmolded with a second component, in this case the expandable material, by way of a second injection apparatus.

(37) If the carrier element is composed of a material which cannot be produced by the injection molding method, thus from a metal, for example, the carrier element is laid up in a respective tool and the carrier element is overmolded with the expandable material. There is of course also the possibility for the expandable material to be fastened to the carrier element by way of special fastening means or methods.