EP4440809A1

EP4440809A1 - Method for producing insulating elements

Info

Publication number: EP4440809A1
Application number: EP22821437.5A
Authority: EP
Inventors: Nuno ROSINHA; Marcel Meister
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2021-11-29
Filing date: 2022-11-22
Publication date: 2024-10-09
Also published as: WO2023094344A1; EP4186677A1; CN118251299A

Abstract

The invention relates to a method for producing an insulating element for insulating a structural element in a motor vehicle, comprising the steps of: extruding a carrier and an expandable material; cutting to length the extrudate; and removing constituents of the carrier and/or of the expandable material from the extrudates, which have been cut to length, for forming individual insulating elements.

Description

Process for the production of insulating elements

The invention relates to a method for producing an insulating element for insulating a structural element in a motor vehicle.

In many cases, components such as bodies and/or frames of means of transport and locomotion, in particular of vehicles on water or on land or of aircraft, have structures with cavities in order to enable lightweight constructions. However, these voids cause various problems. Depending on the type of cavity, it must be sealed to prevent the ingress of moisture and dirt, which can lead to corrosion of the components. It is often also desirable to significantly strengthen the cavities and thus the structural element, while maintaining the low weight. It is also often necessary to stabilize the cavities, and hence the components, to reduce noise that would otherwise be transmitted along or through the cavity. Many of these cavities are irregular in shape or narrow in size, making them difficult to properly seal, reinforce and cushion.

In particular in automobile construction, but also in aircraft and boat construction, sealing elements (baffle) are therefore used to seal cavities and/or acoustically seal them off, or reinforcing elements (English: reinforcer) are used to reinforce cavities.

In Fig. 1 a body of an automobile is shown schematically. The body 10 has various structures with cavities, such as pillars 14 and supports or struts 12 . Such structural elements 12, 14 with cavities are usually sealed or reinforced with sealing and/or reinforcing elements 16.

A disadvantage of the previously known sealing and / or reinforcing elements is that for each body shape and for each cavity of a body individually custom item needs to be manufactured. This leads to high development and production costs and is particularly disadvantageous in the case of smaller vehicle series.

It is therefore an object of the present invention to provide an improved insulating element for insulating a structural element in a motor vehicle, which avoids the disadvantages of the prior art. In particular, the insulating element is intended to provide economic advantages in the case of small series and to reduce overall development and production costs for the insulating elements.

This object is achieved by a method for producing an insulating element for insulating a structural element in a motor vehicle, the method comprising the steps of: Extruding a carrier and an expandable material in an extrusion direction, with a cross section of the extrudate perpendicular to the extrusion direction having an essentially rectangular basic shape wherein a maximum width of the extrudate is at most 20% greater than a minimum width of the extrudate, and wherein a maximum height of the extrudate is at most 20% greater than a minimum height of the extrudate; cutting the extrudate to length; and removing components of the carrier and/or the expandable material from the extrudates cut to length to form individual insulating elements.

This solution has the advantage that different types of insulation elements can be produced by such a production method without high costs having to be expended for production tools.

A core idea of the present invention is that insulating elements of various shapes can be produced by removing components of the carrier and/or the expandable material from the cut to length extrudates without having to change the extrusion device or the production tools. Subsequent shaping of the cut-to-length extrudates allows the shaping of insulating elements adapted for different purposes, which originally originate from the same extrudate with the same cross-section. This offers particular cost benefits for smaller series or for Prototypes, for which it is often not worth investing in independent tools.

Furthermore, the method proposed here can also save development costs in many cases, because the method is very variable and adaptable due to the subsequent shaping step through the removal. As a result, the first insulating elements can first be produced and tested, and the insulating elements can be improved or adapted in a successive process.

By providing an essentially rectangular cross-section of the extrudate, subsequent shaping of the cut-to-length extrudate can take place in many different ways. Due to the fact that the cross-section is constant across both its width and its height, the basic properties of the insulating element are retained by subsequent removal. The size of the insulating element can thus be adjusted without losing the intended properties with regard to the insulation.

In connection with this invention, the designation “insulation element” or “insulation” or “insulated” includes elements or structures or process steps for sealing off and/or closing and/or reinforcing and/or insulating a structural element. These different properties of such an insulating element can occur individually or in combination with one another.

In an exemplary embodiment, the extrudate is cut essentially perpendicularly to the direction of extrusion when it is cut to length.

In an alternative embodiment, the extrudate is cut at an angle to the direction of extrusion or in a curved or wavy manner or in a jagged line when being cut to length. In an exemplary embodiment, the carrier is extruded with a first wall and a second wall which are substantially parallel to one another and are connected to one another by at least one rib.

In a first development, the expandable material is extruded between the two walls.

In a second exemplary development, the expandable material is extruded on the outside of the walls, with an area between the walls remaining free of expandable material.

Depending on which functions of the insulating element are more important, the expandable material can be arranged on the carrier in different ways. For example, an arrangement of the expandable material between two walls is particularly suitable for the formation of insulating elements, which are primarily used to seal off and/or close a structural element.

An arrangement of the expandable material on the outer sides of the two parallel walls is particularly suitable for insulating elements which are to be used primarily to reinforce a structural element.

In an exemplary embodiment, the carrier is also extruded with protective walls placed on the outside of the two walls and adjacent to the expandable material.

The provision of such protective walls offers the advantage that mechanical protection of the expandable material can thereby be ensured. This is particularly advantageous for transport and manipulation of the insulating elements.

In an exemplary embodiment, a number of ribs are extruded between the two walls, thereby forming a mechanically strong beam. In an exemplary embodiment, the carrier is extruded as a plate, with the expandable material being extruded on one or both sides of the plate.

In an exemplary embodiment, at least one clip is extruded in one piece with the carrier, which clip protrudes beyond the basic rectangular shape of the cross section of the extrudate.

In an exemplary development, a depth of the clip is reduced so much in the direction of extrusion during removal that one or more clips with a depth of less than 1 cm, in particular less than 0.6 cm, are thereby formed.

The one-piece extrusion and subsequent molding of clips together with the carrier material has the advantage that subsequent steps are no longer necessary to complete the insulating elements.

In an alternative embodiment, the method comprises the additional steps of: forming at least one opening in the extruded carrier; and inserting a prefabricated clip into the opening.

In an exemplary development, the prefabricated clip is formed from a different material than the extruded carrier.

The use of different materials for the clip and carrier offers the advantage that the materials for the respective components can be optimized as a result. For example, a stiffer material may be beneficial for use in the carrier and a softer, more flexible material may be beneficial for forming the clips.

In an exemplary embodiment, a rectangular outline of the extrudate cut to length, which lies in a plane of the extrusion direction and the width of the extrudate, is changed into a non-rectangular shape during the removal.

In an exemplary embodiment, the width of the cross section of the extrudate is reduced in particular during the removal. In an exemplary embodiment, one edge of the rectangular outline of the cut-to-length extrudate is brought into an irregularly shaped line during removal.

In an exemplary embodiment, at least one film is integrated during extrusion in such a way that the at least one film connects the first wall and the second wall of the carrier to one another.

The provision of such a film has the advantage that deformation of the insulating element during expansion of the expandable material can be prevented by the film holding the two walls together.

In an exemplary development, the foil is a metal foil or a plastic foil.

In an exemplary development, the film has a thickness of less than 0.8 mm, in particular less than 0.5 mm, in particular less than 0.3 mm.

In an exemplary development, the film is anchored both in the first wall and in the second wall.

In an exemplary development, at least two or at least three foils are integrated during extrusion.

In an exemplary embodiment, projections are formed during extrusion, which are arranged on the carrier and which protrude into the expandable material.

Such overhangs offer the advantage that delamination of the expandable material can be prevented during and/or after an expansion, in that the connection of the expanding or the expanded material to the carrier is improved. In an exemplary development, the projections are formed from the same material as the carrier, and/or the projections are formed in one piece with the carrier.

In an exemplary development, the overhangs protrude between 2 and 20 mm, in particular between 3 and 15 mm, in particular between 4 and 12 mm, from a carrier structure, in particular from walls or plates of the carrier, into the expandable material.

In an exemplary development, the insulating element has at least two or at least three or at least four or at least five or at least six such overhangs.

In an exemplary development, the projections are arranged essentially perpendicularly to a plate and/or to a wall of the carrier.

In principle, various materials which can be caused to foam can be used as the expandable material. The material may or may not have reinforcing properties. Typically, the expandable material is expanded thermally, by moisture, or by electromagnetic radiation.

Such an expandable material typically includes a chemical or a physical blowing agent. Chemical blowing agents are organic or inorganic compounds which decompose under the influence of temperature, humidity or electromagnetic radiation, with at least one of the decomposition products being a gas. Physical blowing agents which can be used are, for example, compounds which change to the gaseous state of aggregation when the temperature is increased. As a result, both chemical and physical blowing agents are able to create foam structures in polymers.

The expandable material is preferably thermally foamed using chemical blowing agents. Examples of suitable chemical blowing agents are azodicarbonamides, sulfohydrazides, bicarbonates or carbonates. Suitable blowing agents are also commercially available, for example, under the trade name Expancel® from Akzo Nobel, Netherlands, or under the trade name Celogen® from Chemtura Corp., USA.

The heat required for foaming can be introduced by external or by internal heat sources, such as an exothermic chemical reaction. The foamable material is preferably foamable at a temperature of <250°C, in particular from 100°C to 250°C, preferably from 120°C to 240°C, preferably from 130°C to 230°C.

Suitable as expandable materials are, for example, one-component epoxy resin systems which do not flow at room temperature, which in particular have increased impact strength and contain thixotropic agents such as aerosils or nanoclays. For example, such epoxy resin systems have 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 toughness modifiers, 1 to 5% by weight of physical or chemical blowing agents, 10 up to 40% by weight of fillers, 1 to 10% by weight of thixotropic agents and 2 to 10% by weight of heat-activatable hardeners. Suitable toughness modifiers are reactive liquid rubbers based on nitrile rubber or derivatives of polyetherpolyol polyurethanes, core-shell polymers and similar systems known to those skilled in the art.

Also suitable expandable materials are one-component polyurethane compositions containing blowing agents, built up from crystalline polyesters containing OH groups mixed with other polyols, preferably polyether polyols, and polyisocyanates with blocked isocyanate groups. The melting point of the crystalline polyester should be > 50 °C. The isocyanate groups of the polyisocyanate can be blocked, for example, with nucleophiles such as caprolactam, phenols or benzoxalones. Also suitable are blocked polyisocyanates such as are used, for example, in powder coating technology and are commercially available, for example, under the trade names Vestagon® BF 1350 and Vestagon® BF 1540 from Degussa GmbH, Germany. So-called encapsulated or surface-deactivated polyisocyanates, which are known to the person skilled in the art and are described, for example, in EP 0204 970, are also suitable as isocyanates. Also suitable as expandable materials are two-component epoxy/polyurethane compositions containing blowing agents, as are described, for example, in WO 2005/080524 A1.

Also suitable as expandable materials are ethylene-vinyl acetate compositions containing blowing agents.

Likewise suitable expandable materials are marketed, for example, under the trade name SikaBaffle® 240, SikaBaffle® 250 or SikaBaffle® 255 by Sika Corp., USA, and are described in patents US Pat. No. 5,266,133 and US Pat. No. 5,373,027. Such expandable materials are particularly preferred for the present invention.

Preferred expandable materials with reinforcing properties are, for example, those sold under the trade name SikaReinforcer® 941 by Sika Corp., USA. These are described in US 6,387,470.

In an exemplary embodiment, the expandable material has an expansion rate of 800% to 5000%, preferably 1000% to 4000%, more preferably 1500% to 3000%.

Expandable materials with such expansion rates offer the advantage that reliable sealing or insulation of the structural element against liquids and noise can be achieved.

In an exemplary embodiment, the expandable material is in the form of a temperature-induced material.

This has the advantage that the oven can be used to bake the dip coating liquid in order to expand the expandable material and thereby insulate the cavity. This means that no additional work step is necessary. In an exemplary embodiment, the expandable material is made from two different materials during extrusion.

In an exemplary development, the two expandable materials differ in particular with regard to an expansion rate and/or a temperature range for the expansion.

The carrier can be made of any materials. Preferred materials are plastics, in particular polyurethanes, polyamides, polyesters and polyolefins, preferably high-temperature-resistant polymers such as poly(phenylene ether), polysulfones or polyether sulfones; or any combination of these materials. Polyamide, in particular polyamide 6, polyamide 6.6, polyamide 11, polyamide 12 or a mixture thereof is particularly preferably used.

In an exemplary embodiment, the carrier is produced entirely or partially from Plexiglas (polymethyl methacrylate or PMMA for short) during extrusion.

In an exemplary embodiment, the carrier is made entirely or partially of polyamide 6, or polyamide 6.6, or polyamide 6.10, or polyamide 11, or polyamide 12, or a mixture thereof during extrusion.

In an exemplary embodiment, the carrier is formed in whole or in part from nylon 10 during extrusion.

Details and advantages of the invention are described below using exemplary embodiments and with reference to schematic drawings. Show it:

1 shows an exemplary illustration of a body;

Fig. 2a to 2c an exemplary representation of a method for producing a

insulating element; and 3a to 6 schematic representation of exemplary cross sections of the extrudates.

In Figs. 2a to 2c, a method for producing an insulating element 16 is shown as an example and schematically. 2a shows the extrudate 1, FIG. 2b shows an extrudate 2 cut to length and FIG. 2c finally shows the finished insulating element 16.

The extrusion direction 15 is shown in FIG. 2a. A cross section of the extrudate 1 perpendicular to the extrusion direction 15 has a rectangular basic shape, with a height 4 and a width 3. A maximum width 3 of the extrudate 1 is at most 20% greater than a minimum width 3 of the extrudate 1. In addition, there is a maximum height 4 of the extrudate 1 is also at most 20% greater than a smallest height 4 of the extrudate 1.

In this exemplary embodiment, the carrier 11 comprises both two parallel walls and ribs running between the walls.

In this exemplary embodiment, the extrudate 1 is cut essentially perpendicularly to the direction of extrusion 15 when it is cut to length. The resulting extrudates 2 cut to length are then further processed by removing components of the extrudate 2 cut to length. In this exemplary embodiment, only parts of the carrier 11 are removed. In the process, the carrier 11 is removed in the area of the parallel walls and in the area of the extruded clip 17 to such an extent that a clip 17 with a depth 18 of less than 1 cm is formed, and that spacer elements 20 are formed by the walls, which are Positioning of the insulating element in the structural element are helpful.

Various exemplary embodiments of cross sections of an extrudate or an insulating element 16 are shown in FIGS. 3a to 4c. 3a to 3c each show insulating elements 16 in which the clips 17 are formed integrally with the carrier 11, and FIGS. 4a to 4c show different examples of insulating elements 16, in which the clip is formed as a separate part, which is then arranged in an opening 19 of the carrier 11.

The insulating element 16 according to FIG. 3a has a first wall 5 and a second wall 6 of the carrier 11, which are connected to one another by two ribs 7. Expandable material 13 is arranged between the first wall 5 and the second wall 6 .

Another exemplary insulating element 16 is shown in FIG. 3b. In this exemplary embodiment, the carrier is extruded as a plate 9, with expandable material 13 being extruded on both sides of the plate 9. FIG.

In Fig. 3c another example of an insulating element is shown. The carrier 11 in turn comprises a first wall 5 and a second wall 6, with several ribs 7 connecting the two walls 5, 6 to one another in this example. In this embodiment, the expandable material 13 is arranged on the outside of the walls 5,6. In each case protective walls 8 are arranged next to the expandable material 13 in order to prevent damage to the expandable material during transport and manipulation of the insulating elements 16 . In this embodiment, the space between the first wall 5 and the second wall 6 is free of expandable material 13.

In Fig. 4a again an exemplary insulating element is shown. Here the expandable material 13 is also arranged on the outside of the first wall 5 and the second wall 6 and is protected from mechanical influences by protective walls 8 . The exemplary insulating element 16 in FIG. 4b again has a first wall 5 and a second wall 6. In this exemplary embodiment, the two walls 5, 6 are connected to one another by three ribs 7, two of these ribs being arranged obliquely with respect to a height of the cross section are.

Finally, FIG. 4c shows an insulating element 16 which in turn comprises a plate 9 . In this exemplary embodiment, expandable material 13 is only arranged on one side of the plate 9, the other side of the plate 9 being free of expandable material. FIG. 5 shows another exemplary insulating element 16 which has a carrier 11 with a first wall 5 and a second wall 6 . Expandable material 13 is in turn arranged between the walls 5 , 6 . In this exemplary embodiment, the insulating element 16 also has a film 21 which connects the two walls 5, 6 to one another. The film 21 is preferably anchored in the walls 5, 6. When the expandable material 13 expands, the film 21 can prevent the two walls 5, 6 from being pushed apart too much by the expanding material or from deforming the insulating element 16.

A further exemplary insulating element 16 is shown in FIG. 6 . In this embodiment, the carrier 11 also has a top wall 5 and a bottom wall 6, and expandable material 13 arranged between the walls 5, 6. In addition, the insulating element 16 has a plurality of projections 22 which are arranged on the carrier 11 and in the expandable material 13 protrude. These projections 22 mean that a delamination of the expandable material 13 can be prevented during and/or after an expansion, in that the connection of the expanding or the expanded material 13 to the carrier 11 is improved.

Reference List

1 extrudate

2 cut to length extrudate

3 width

4 height

5 first wall

6 second wall

7 rib

8 protective wall

9 plate

10 body

11 carriers

12 structural element

13 expandable element

14 structural element

15 extrusion direction

16 insulating element

17 clips

18 depth

19 opening

20 spacer

21 slide

22 overhang

Claims

patent claims

1. A method for producing an insulating element (16) for insulating a structural element (12, 14) in a motor vehicle, the method comprising the steps:

Extruding a carrier (11) and an expandable material (13) in an extrusion direction (15), wherein a cross section of the extrudate (1) perpendicular to the extrusion direction (15) has an essentially rectangular basic shape, with a greatest width (3) of the extrudate (1) is at most 20% greater than a smallest width (3) of the extrudate (1), and wherein a greatest height (4) of the extrudate (1) is at most 20% greater than a smallest height (4) of the extrudate (1 );

cutting the extrudate (1) to length; and

Removing components of the carrier (11) and/or the expandable material (13) from the extrudates (2) cut to length to form individual insulating elements (16).

2. The method according to claim 1, wherein the extrudate (1) is cut substantially perpendicularly to the direction of extrusion (15) when being cut to length.

A method according to any one of the preceding claims, wherein the carrier (11) is extruded with a first wall (5) and a second wall (6) which are substantially parallel to each other and are interconnected by at least one rib (7).

4. The method according to claim 3, wherein the expandable material (13) is extruded between the two walls (5, 6).

A method according to claim 3, wherein the expandable material (13) is extruded on outsides of the walls (5, 6), leaving an area between the walls (5, 6) free of expandable material (13).

A method according to claim 5, wherein the support (11) is also extruded with protective walls (8) placed on the outside of the two walls (5, 6) and adjacent to the expandable material (13).

7. A method according to any one of claims 5 or 6, wherein the expandable material (13) has an expansion rate of 300 to 1200%.

8. The method according to any one of claims 5 to 7, wherein between the walls (5, 6) a plurality of ribs (7) are extruded to form a mechanically strong support (11).

9. The method according to any one of claims 1 or 2, wherein the carrier (11) is extruded as a plate (9), and wherein the expandable material (13) is extruded on one or both sides of the plate (9).

10. The method according to any one of the preceding claims, wherein at least one clip (17) is extruded in one piece with the carrier (11), which clip protrudes beyond the basic rectangular shape of the cross section of the extrudate (1).

11. The method according to claim 10, wherein during removal a depth (18) of the clip (17) in the extrusion direction (15) is reduced to such an extent that one or more clips (17) with a depth (18) of less than 1 cm be formed.

12. The method according to any one of claims 1 to 9, wherein the method comprises the additional steps:

forming at least one opening (19) in the extruded support (11); and inserting a prefabricated clip into the opening (19).

13. The method according to claim 12, wherein the prefabricated clip is formed from a different material than the extruded carrier (11).

14. The method according to any one of the preceding claims, wherein during the removal a rectangular outline of the cut to length extrudate (2), which lies in a plane of the extrusion direction (15) and the width (3) of the extrudate, is changed into a non-rectangular shape. 17

15. The method according to any one of the preceding claims, wherein a width (3) of the cross section of the extrudate (1) is reduced during removal.