A THERMALLY INSULATING PROFILE

Abstract

 A thermally insulating profile, suitable for being interposed between two profiles (2) made of conductive material for making a thermal break system (3), comprises a body (4) obtained by extruding a thermoplastic material, extending longitudinally and provided with at least one projection (5), and an adhesion element (11), extending longitudinally, coextruded at the projection (5) of the body (4) made of thermoplastic material.

Description

[0001] This invention relates to a thermally insulating profile, in particular suitable for being interposed between profiles made of conductive material for making a thermal break system.

[0002] Thermal break systems, which allow a reduction in heat exchange between the outside and the inside, consist of thermally conductive profiles, typically metal profiles, and of profiles made of thermoplastic material which connect the conductive profiles. Thermoplastic materials commonly used are, for example, ABS, PVC, polyamide and, more recently, mixtures comprising polyphenylene ether and polyamide (PPE+PA).

[0003] The insulating profile is connected to the metal profiles before the step of coating in an oven. The insulating profile comprises a body extending longitudinally provided with projections which are inserted into corresponding seats made in the metal profiles. In particular, the metal profiles have anchoring elements which between them create the seat suitable for receiving the projection of the insulating profile, wherein one of the elements is mechanically clamped on the projection after insertion.

[0004] After having connected the insulating profile to the metal profiles, a longitudinal shearing strength test is carried out to verify the suitability of the assembly which is performed by locking the first metal profile and applying a force on the second metal profile.

[0005] Since the polymerisation of the coating powders occurs by heating to approximately 180°-200°C for approximately 20 minutes, the coating process on the assembled unprocessed profile causes a reduction in the longitudinal shearing strength of up to approximately 30% compared with the value obtained before coating. This is also due to the fact that, during the heating, the material of the insulating profile tends to lose the moisture content, causing a reduction in dimensions.

[0006] To avoid a situation in which after the coating process the tensile strength becomes insufficient, a line of glue is usually applied inside one or more cavities made in the projections of the insulating profile.

[0007] During the powder coating process, as the glue heats up its volume increases, it melts, comes out of the cavity, presses on the surface of the metal profile and creates improved adherence between the insulating profile and the metal profiles.

[0008] However, since in coating ovens bars measuring approximately 6 metres, consisting of the insulating profile connected to the metal profiles, are placed vertically, after heating the glue melts and partly drips below the bar. Above all at the parts of the bar positioned higher up in the oven, the amount of glue which at the end of the coating process remains interposed between the insulating profile and the metal profile is small, consequently in those parts reducing the gripping action between the insulating profile and the metal profile.

[0009] To overcome that disadvantage, adhesion wires have been made consisting of materials which comprise both an adhesive and a carrier material.

[0010] A first type of adhesion wire consists of an inner core of thermoplastic material, which does not melt at the temperature of the coating oven, and of a reduced thickness outer covering of adhesive material.

[0011] A second type of adhesion wire comprises a mixture of adhesive and carrier material. In this second type of adhesion wire, the carrier material helps to retain the adhesive melted during high temperature coating in the oven of the assembled profile, in such a way that the adhesive remains uniformly distributed along the whole thermally insulating profile.

[0012] For each thermally insulating profile, adhesion wires of predetermined length are cut, usually slightly less than the length of the profile itself, and they are mechanically inserted into the cavities of the projections which connect the insulating profile to the metal profiles.

[0013] Mechanical insertion of the adhesion wire into the cavities of the thermoplastic profile not only complicates the production process, but also involves several disadvantages.

[0014] The adhesion wire has a very small diameter, of approximately 1.2 mm, and must precisely match the diameter of the cavity into which it is inserted. If the adhesion wire is not perfectly inserted into the cavity, at the moment of assembly with the metal profiles the insulating profile must be discarded because it is not possible to insert it into the seats made in the metal profiles. Moreover, the adhesion wire may detach from the profile, completely coming out of the cavity.

[0015] The adhesion wire may be made only with predetermined minimum dimensions and therefore the amount of glue is always the same irrespective of what is actually necessary for adhesion of a particular profile.

[0016] Moreover, when assembling the insulating profile with the metal profile the projection of the insulating profile is inserted into the seat of the metal profile shaped to match it and one of the metal anchoring elements is "closed" at the connecting zone between the projection and the body of the profile. When an adhesion wire is used, a circular cavity is made inside the projection, which therefore involves a reduction in the thickness precisely in the zone subjected to the greatest stress during the step of inserting the projection into the seat of the metal profile.

[0017] The aim of this invention is to provide a thermally insulating profile which improves assembly with the metal profile.

[0018] A further aim of this invention is to increase the stability and strength of the assembled profile consisting of the insulating profiles and metal profiles. According to the invention, a thermally insulating profile is provided having the features defined in claim 1.

[0019] According to another aspect of this invention, a method for making a thermally insulating profile has the features defined in claim 10.

[0020] Coextrusion of the adhesion element on the body made of thermoplastic material, as well as simplifying the production process, makes it possible to avoid any removal of the adhesion element during assembly with the metal profile.

[0021] Indeed, the insulating profile prepared for adhering to the metal profile is supplied in one piece. If, due to manufacturing defects, the adhesion element were to be of a size not suitable for assembly, for example if it were to project too far from the body of the profile, it would be possible to act on the profile itself before assembly by mechanically adjusting it during the coextrusion step or immediately discarding the profile, therefore avoiding supplying profiles unsuitable for assembly.

[0022] Moreover, the shape and size of the adhesion element may be determined on a case by case basis, depending on the amount of glue required for a specific profile.

[0023] Further advantages and features of this invention will be more apparent in the detailed description which follows, with reference to the accompanying drawings, which show an example, non-limiting embodiment, in which:

• Figure 1 illustrates a thermally insulating profile according to a preferred embodiment of this invention;
• Figure 2 illustrates a thermal break system which uses a profile having a bar-style geometry;
• Figure 3 illustrates a thermal break system which uses two profiles having a different geometry;
• Figure 4 illustrates a detail of the thermal break system with an insulating profile according to a first embodiment;
• Figure 5 illustrates a detail of the thermal break system with an insulating profile according to an alternative embodiment.

[0024] In Figure 1, the numeral 1 denotes a thermally insulating profile. Figure 1 illustrates a possible geometry of the insulating profile 1 having a bar-shaped cross-section. As illustrated in Figure 2, the insulating profile 1 is interposed between two profiles 2 made of conductive material to form a thermal break system 3. The profiles 2 made of conductive material are usually metal profiles. The insulating profile may have different geometries, solid or so-called "hollow chamber". Figure 3 illustrates a thermal break system 3 using a shaped solid insulating profile 1' and a "hollow chamber" insulating profile 1" which has a complex geometry.

[0025] The following description will refer to an insulating profile irrespective of the particular geometry.

[0026] The insulating profile 1 comprises a body 4 extending longitudinally obtained by extruding a thermoplastic material. The body 4 is provided with at least one projection 5, suitable for being inserted into a corresponding seat 6 made in a profile 2 made of conductive material.

[0027] According to the invention, the insulating profile 5 comprises an adhesion element 11, extending longitudinally, coextruded at the projection 5 of the body 4. The adhesion element is coextruded on the body 4 extending longitudinally.

[0028] Therefore, the insulating profile 1 consists of one piece comprising the body 4 made of thermoplastic material and the adhesion element 11.

[0029] In the embodiment illustrated, the projection 5 has at least one cavity 7 open towards the outside. In the assembled thermal break system 3, the cavity 7 is therefore directed towards the conductive profile 2 at the seat 6. In the insulating profile 1 the adhesion element 11 is coextruded on the body 4 extending longitudinally inside the cavity 7.

[0030] Advantageously the surface 12 of the insulating profile 1 suitable for making contact with the conductive profile 2 has at least one recessed portion 13 at the cavity 7. The recessed portion 13 allows the melted adhesive material to be distributed in the seat 6 of the conductive profile 2 in such a way as to improve adherence and avoid build-ups of material between the insulating profile 1 and the metal profile 2.

[0031] In the embodiment of Figure 1, the insulating profile 1 has two projections 5 having a substantially trapezoidal cross-section. The smaller base 8 of the substantially trapezoidal cross-section is connected to the body 4 of the profile 1. The cavity 7 of the projection 5 of the insulating profile 1 is open towards the larger base 9 of the trapezoidal cross-section. The larger base 9 of the substantially trapezoidal cross-section is suitable for making contact with the conductive profile 2 at the seat 6. The larger base 9 advantageously has a recessed portion 13 at the cavity 7.

[0032] The seat 6 is made between two anchoring elements 10 of the conductive profile 2. As illustrated in Figure 4, during assembly, one of the anchoring elements 10 of the conductive profile 2 is shifted into an open position (indicated with the unbroken line) to receive the projection 5 of the insulating profile 1 and after insertion is brought into a closed position (indicated with the broken line) so as to lock the projection 5 of the insulating profile 1 in the seat 6 of the metal profile 2. In one embodiment the adhesion element 11 has a substantially circular cross-section. In that embodiment, the diameter of the adhesion element 11 is preferably between 1 mm and 1.3 mm, in particular 1.2 mm.

[0033] In other embodiments the adhesion element 11 may have cross-sections having a shape different from circular.

[0034] Since the adhesion element does not have to be mechanically inserted for it to be contained inside its seat in the subsequent steps, the shape of the adhesion element can be freely selected based on an assessment carried out on a case by case basis.

[0035] Even the size of the adhesion element can be freely determined on a case by case basis according to the amount of glue necessary for adhesion of a predetermined profile.

[0036] For cross-sections other than the circular one, the maximum size of the cross-section of the adhesion element 11 is preferably between 1 mm and 1.3 mm, in particular 1.2 mm.

[0037] In a further embodiment, the cross-section of the adhesion element 11 is substantially rectangular. This allows limitation of the reduction in thickness at the points of the projection 5 which surround the cavity 7 and which are subjected to the greatest stresses during assembly, but keeping a sufficient amount of adhesive material.

[0038] In one advantageous embodiment, the smaller side of the rectangle has a size of between approximately 0.3 mm and approximately 0.8 mm.

[0039] Moreover, the size of the opening of the cavity 7 towards the outside can be reduced, in such a way as to prevent excessive discharge of adhesive material during heating, which could compromise the strength of the assembled system.

[0040] In particular, in the case of a rectangular cross-section, the size of the opening may be less than the size of the larger side of the rectangle.

[0041] A method for making the insulating profile 1 comprises the steps of extruding a body 4 made of thermoplastic material extending longitudinally and provided with at least one projection 5 and of coextruding an adhesion element 11, extending longitudinally, at the projection 5 of the body 4 made of thermoplastic material. The adhesion element 11 is coextruded on the body 4 extending longitudinally.

[0042] The adhesion element 11 advantageously comprises an adhesive.

[0043] In one embodiment the material of the adhesion element 11 may be an adhesive commonly used for adhesion wires.

[0044] In one preferred embodiment, the material of the adhesion element 11 contains a mixture comprising a carrier material and an adhesive.

[0045] In that embodiment the insulating profile comprises a body 4 extending longitudinally obtained by extruding a thermoplastic material and an adhesion element 11 extending longitudinally and consisting of a material which contains a mixture comprising carrier material and an adhesive, wherein the body 4 extending longitudinally is provided with at least one projection 5 suitable for being inserted into a corresponding seat 6 made in a profile 2 made of conductive material, and the adhesion element 11 is coextruded on the body 4 made of thermoplastic material at the projection 5 of the body 4.

[0046] According to one preferred embodiment, the method for making the insulating profile comprises the steps of extruding a body 4 made of thermoplastic material extending longitudinally and provided with at least one projection 5 and of coextruding on the body 4 made of thermoplastic material at the projection 5 an adhesion element 11 extending longitudinally, wherein the adhesion element 11 consists of a material containing a mixture comprising a carrier material and an adhesive.

[0047] In one particular embodiment, the coextrusion of the adhesion element 11 on the body 4 is carried out after extrusion of the body 4 made of thermoplastic material ("post coextrusion"). Alternatively, the coextrusion of the adhesion element 11 on the body 4 is carried out together with extrusion of the body 4 made of thermoplastic material.

[0048] The carrier material is a material which does not melt at the temperatures used in the ovens. Preferably the carrier material has a melting point higher than 200°C. The carrier material therefore remains in the solid state during coating in the oven of the assembly of which the thermal break system consists.

[0049] The mixture comprises from 30% to 50% by weight of the carrier material. The mixture comprises from 50% to 70% by weight of the adhesive. In a preferred solution the mixture comprises approximately 45% by weight of the carrier material and approximately 55% by weight of the adhesive.

[0050] Before the mixing, the adhesive and the carrier material are advantageously in the granular state. That mixture of the adhesive and the carrier material is preferably heterogeneous. The adhesive and the carrier material are uniformly distributed in the mixture. This allows a homogeneous expansion of the adhesion element.

[0051] The carrier material helps to retain the melted adhesive during high temperature coating in the oven of an assembly consisting of one or more thermally insulating profiles and the thermally conductive profiles. This prevents the adhesion element from dripping onto the bottom of the oven. In this way the adhesive remains uniformly distributed along the whole thermally insulating profile.

[0052] The carrier material advantageously does not chemically react with the adhesive. The carrier material advantageously comprises a thermoplastic resin, for example a polyamide, in particular nylon 6.

[0053] The adhesive comprises an ethylene and acrylic acid copolymer. Following heating, the adhesive tends to melt and its volume increases. The adhesion element expanded following heating (typically coating in an oven) remains in that expanded state even following subsequent cooling.

[0054] The adhesive appropriately comprises from 6% to 15% by weight of acrylic acid, preferably 9% by weight of acrylic acid.

[0055] In one preferred embodiment the mixture of the material of the adhesion element is approximately 45% PA6 and approximately 55% an ethylene and acrylic acid copolymer.

[0056] The insulating profile according to this invention therefore allows simplification of the production process because it does not comprise separately making an adhesion wire which must be mechanically assembled on the extruded insulating profile.

[0057] This also avoids errors during assembly of the wire in the cavity, which make it impossible to insert the insulating profile into the seat of the metal profile.

Claims

1. A thermally insulating profile, suitable for being interposed between two profiles (2) made of conductive material for making a thermal break system (3), said insulating profile comprising a body (4) obtained by extruding a thermoplastic material, extending longitudinally and provided with at least one projection (5), and an adhesion element (11), extending longitudinally, coextruded at the projection (5) of the body (4) made of thermoplastic material.

2. The thermally insulating profile according to claim 1, characterised in that the projection (5) is provided with a cavity (7) open towards the outside of the insulating profile and the adhesion element (11) is coextruded inside the cavity (7) of the projection (5).

3. The thermally insulating profile according to claim 1 or 2, characterised in that the maximum size of the cross-section of the adhesion element (11) is between 1 mm and 1.3 mm, in particular 1.2 mm.

4. The thermally insulating profile according to any one of the preceding claims, characterised in that the cross-section of the adhesion element (11) has a substantially rectangular shape.

5. The thermally insulating profile according to claim 4, characterised in that the smaller side of the rectangular cross-section has a size of between approximately 0.3 mm and approximately 0.8 mm.

6. The thermally insulating profile according to claim 4 or 5, characterised in that the size of the opening of the cavity (7) towards the outside of the insulating profile is less than the size of the larger side of the rectangular cross-section.

7. The thermally insulating profile according to any one of the preceding claims, characterised in that the material of the adhesion element (11) contains a mixture comprising a carrier material and an adhesive.

8. The thermally insulating profile according to claim 7, characterised in that the mixture comprises from 30% to 50% by weight of the carrier material and from 50% to 70% by weight of the adhesive.

9. The thermally insulating profile according to claim 7 or 8, characterised in that the adhesive comprises an ethylene and acrylic acid copolymer.

10. A method for making an insulating profile (1) according to any one of the preceding claims, comprising the steps of extruding a body (4) made of thermoplastic material extending longitudinally and provided with at least one projection (5) and coextruding an adhesion element (11) extending longitudinally at the projection (5) of the body (4) made of thermoplastic material.

11. The method according to claim 10, characterised in that it comprises the step of coextruding on the body (4) made of thermoplastic material extending longitudinally an adhesion element (11) consisting of a material containing a mixture comprising a carrier material and an adhesive.

12. The method according to claim 11, characterised in that the mixture comprises from 30% to 50% by weight of the carrier material and from 50% to 70% by weight of the adhesive.

13. The method according to claim 11 or 12, characterised in that the adhesive comprises an ethylene and acrylic acid copolymer.

14. The method according to any one of the claims 11 to 13, characterised in that the carrier material comprises a thermoplastic resin.

Drawing