EP2591196A1

EP2591196A1 - Frame profile comprising foamed insert, use of such frame profile, kit of parts of a frame profile and a foam insert and window or door comprising such frame profile

Info

Publication number: EP2591196A1
Application number: EP11729423.1A
Authority: EP
Inventors: Koen Vanlandschoot; Peter Spanhove; Laura Jonckheere; Mario Genetello
Original assignee: Recticel NV SA
Current assignee: Recticel NV SA
Priority date: 2010-07-05
Filing date: 2011-07-05
Publication date: 2013-05-15
Anticipated expiration: 2031-07-05
Also published as: EP2591197A1; EP2591196B1; WO2012004277A1; WO2012004278A1

Abstract

A frame profile comprising a foamed insert, characterized in that said foam is shape memory polymer foam.

Description

FRAME PROFILE COMPRISING FOAMED INSERT, USE OF SUCH FRAME PROFILE, KIT OF PARTS OF A FRAME PROFILE AND A FOAM INSERT AND

WINDOW OR DOOR COMPRISING SUCH FRAME PROFILE Field of the Invention

The present invention concerns a frame profile comprising a foamed insert, in particular a profile for manufacturing a frame of a door or window. Background of the Invention

Window frames and door frames are known to be manufactured in aluminum or PVC or wood. Aluminum frames generally comprise profiles with an inner and an outer shell coupled by a thermal bridge. This thermal bridge is known to comprise a structure in a non-thermal conductive material such as polyamide, extending between the inner shell and outer shell, thereby defining one or several inner chambers. This thermal bridge does not or only on a very limited scale provide structural strength to the profile and should be kept as small as possible to ensure structural integrity of the profile as such. As with PVC frames, the structural strength of the profile is key to minimizing width of the frame for supporting a glass panel or such.

EP 2,080,864 discloses an insert for frame profiles comprising a thermal insulating foam and a structural strengthening band embedded therein. An inconvenience of this type of insert is that it is rather difficult to insert it into the inner chamber of a profile and in that it does not provide a support over the entire surface of the inner chamber wherein the insert is provided.

It is clear from the above that there remains a demand for alternative cost and performance effective frame profiles having equal to improved overall structural properties and which at the same time have improved functionalities. The present invention meets this demand by providing a specific foamed insert for frame profiles.

Summary of the Invention

The present invention concerns a frame profile comprising a foamed insert, characterized in that said foam is shape memory polymer foam. The present invention further concerns a kit of parts comprising a frame profile having an inner chamber and a shape memory polymer foam strip, the foam having a Tg above room temperature (20°C).

The present invention further addresses the use of a shape memory polymer foam as an insert for a profile for the manufacturing of a frame and a door or window comprising such a frame profile.

Finally, the present invention concerns a method for manufacturing such a frame profile.

Description of the Invention

The frame profile preferably comprises walls defining an inner chamber wherein said foam is inserted in its compressed state and wherein substantially the entire outer surface of the foam insert contacts the inner surface of said inner chamber upon foam expansion.

The foam used for the insert is preferably a polyurethane foam with a Tg (glass transition temperature) above room temperature, preferably between 20 and 120°C, more preferably between 30 and 70°C, even more preferably between 40 and 60°C and even more preferably between 50 and 55°C. The kit of parts, wherein the foam strip is compressed to have a cross section dimension smaller than the cross section dimension of the inner chamber of the profile. Brief Description of the Drawings

Figure 1 represents a cross sectional view of an aluminum type of frame profile according to the present invention;

Figure 2 represents a cross sectional view of a frame profile after insertion of a compressed shape memory polymer foam strip;

Figure 3 represents a cross sectional view of a PVC type of frame profile according to the present invention.

Description of a preferred Embodiment

Figure 1 and Figure 2 represent a cross sectional perspective view of an aluminum type of frame profile 1 according to the present invention. The profile comprises an inner shell 2 and an outer shell 3 that are connected to each other by a thermal bridge 4. In the present embodiment, the thermal bridge comprises two legs 5, 6 each extending longitudinally and at a distance from each other between the inner shell 2 and the outer shell 3, thereby defining an inner chamber 7.

Figure 3 represents a PVC type frame profile according to the present invention, the profile comprising at least four longitudinally extending legs defining an inner chamber 8.

The inner chamber is provided with a foam insert 9 so that substantially the entire outer surface 9 of the foam insert contacts the inner surface of said inner chamber 7, 8.

According to the present invention, the foam is a shape memory polymer foam, preferably a shape memory polyurethane (PU) foam. Shape memory polymer foams are hereby defined as foams that remain compressed (or deformed) if they are compressed at a temperature higher than the glass transition temperature (Tg) of the polymer and then cooled below Tg in their compressed or deformed state. They substantially recover from their compressed state to their expanded state when heated to a temperature higher than Tg. The expanded state is the shape of the shape memory material after it is manufactured and before it is compressed. The recovery of the foam to its expanded shape is referred to as "shape memory".

The shape memory polymer foam of the present invention can be made from styrene-butadiene polymers, crystalline diene polymers, norbornane polymers, and the like. Most preferably, the shape memory polymer foam is a polyurethane foam or a poly-isocyanate based foam having a Tg which is above room temperature. The foam is rigid at room temperature and becomes elastic when it is heated above the Tg.

The properties, such as Tg, of the shape memory polyurethane foam are achieved by careful selection of the polyurethane foam forming components, such as the used polyisocyanate (not limited to TDI, MDI, NCO-terminated prepolymer), the used polyol (not limited to a polyether, polyester, polycarbonate, OH-terminated prepolymer), and the used chain extender. In addition, these properties can be tailored in such a way that even below Tg, i.e. in rigid state, the foam can be mechanically compressed up to 25 % without destructing the cellular foam structure and even fulfilling its shape memory function at temperatures above Tg.

On the one hand, the PU foam preferably has a Tg above room temperature and below the melting or deterioration temperature of the most heat sensitive material delimiting the chamber wherein the foam is inserted. In case the thermal bridge is designed as a structure defining one or more inner chambers on its own, the Tg of the shape memory polymer foam is preferably not higher than the temperature to which the thermal bridge itself (i.e. in an non-assembled state with the outer and inner shells 2, 3) can be exposed without damaging it. For a thermal bridge manufactured in polyamide or derivatives thereof or for profiles in PVC, the Tg of the shape memory polymer foam is preferably below 55°C. On the other hand it is preferred that the shape memory polymer foam has a Tg higher than room temperature such that it can easily be stored and transported in a compressed form, without expanding. In view of the above a Tg of the shape memory polymer foam ranging between 20°C and 120°C, or better between 30 and 70°C, or even better between 40°C and 60°C is preferred. Most preferred is a Tg ranging between 50°C and 55°C, in which case the shape memory polymer foam remains in its structurally more rigid condition at normal temperatures to which door- and window frames are exposed in normal use. The shape memory polymer foam preferably has an open cell structure. The open cell structure can be achieved in various ways, for example by appropriate selection of cell openers and/or surfactants, or by reticulation methods applied on foams in their elastic state (above Tg). The open cell structure of the foam allows it to be compressed to a much larger degree. If the shape memory polymer foam is of closed cell structure, it recovers to its original shape rapidly upon expansion of the cell gas which has been compressed in the cells during compression.

The cells in the shape memory polymer foam should have a cell diameter in the range of between 100 μιτι and 800 μιτι or lower in order to obtain good thermal insulation properties. The foam is further preferably a hydrophobic foam to prevent water absorption and loss of thermal insulation properties over an extended period of time.

The shape memory polymer foam may have a cellular or a micro-cellular structure, having a density (in expanded state) in the range of from 20 kg/m³ and 800 kg/m³. Most preferably the shape memory polymer foam has a density between 25 kg/m³ and 200 kg/m³, in view of the ease of compression.

The shape memory polymer foam is further characterized by a compression strength (hardness) of between 150 kPa and 300 kPa at 15 % compression and of between 170 and 370 kPa at 40 % compression, when measured with following test method. A polymer foam sample with a dimension of 10 cm (length) * 10 cm (width) * 2 cm (height) is compressed (after 24 hours of conditioning at 23±2 °C and a relative humidity of 50±10 %) in the height direction at a rate of 120 mm/min. The compression force at 15 % and at 40 % compression is then measured.

The foam preferably has a compression modulus of at least 500 kPa, preferably at least 1000 kPa, preferably at least 2000 kPa, more preferably at least 2500 kPa, most preferably at least 3000 kPa, while compression moduli up to 10000 kPa or more should not be excluded.

The bending strength of the shape memory foam preferably ranges between 25 and 500 kPa, when measured with following test method. A polymer foam sample with a dimension of 12 cm (length) * 2 cm (width) * 1 cm (height) is (after 24 hours of conditioning at 23±2 °C and a relative humidity of 50±10 %) positioned on supports that are spaced apart at a distance of 10 cm. The foam sample is bent at a constant rate of 50 mm/min. The bending force is measured at sample fracture or at a maximum bending of 40 mm.

The bending modulus of the foam is preferably at least 500 kPa, preferably at least 750 kPa, more preferably at least 1000 kPa and can range upto 5000 kPa and even 9000 kPa or more.

The shape memory foam preferably has a fixity rate of at least 0,70, preferably at least 0,80, most preferably at least 0,90, wherein the fixity rate is measured by:

- compressing the foam block (Tg between 50 and 70°C) at 100°C;

- cooling the foam block while maintaining the compression force on the block to a temperature of 25 °C

- releasing the compression force and maintaining the temperature at 25 °C

- measuring the height of the block 30 minutes after release of the compression force. The fixity rate is than calculated by height of block at 25°C before release / height of block at 25 °C 30 minutes after release.

It is believed that a frame profile according to the present invention can exhibit improved structural properties of the thermal bridge or parts of the profile due to the presence of the expanded shape memory polymer foam exerting an evenly divided pressure outwardly directed on the side walls of the inner chamber 7, 8. The evenly divided pressure is preferably achieved by dimensioning the foam strip such that when allowed to fully expand to its original dimensions, it has a height or width or a height and width larger than the height and/or width of the inner chamber wherein it is inserted

In the case of the embodiment represented in figure 1 , the profile is assembled by inserting the foam, which will be typically in the form of a strip 10 of compressed shape memory polymer foam having cross sectional dimensions (height or width or both) smaller than the cross sectional dimensions (height or width or both) of the inner chamber, in that inner chamber 7, 8, such as represented in figure 2. Compression of the foam strip can be for example achieved on site by introducing an expanded foam strip between a pair of rolls (heated slightly above the Tg of the foam) and immediate insertion of the compressed strip in the profile. Clearly it is also possible to compress the strip upfront, example given, by the foam strip manufacturer and transporting the compressed foam strip 10 to the site where the strip is inserted in the profile. Subsequently, the profile can be heated up to a temperature above the Tg of the shape memory polymer foam used, such that the foam strip will expand until it takes the shape of the inner chamber thereby contacting substantially the entire inner surface of said inner chamber 7, 8. This method, wherein the foam is expanded in the profile before sizing the profile, allows to obtain a good control on the use of the foam and especially to guarantee that the foam is applied over the entire length of the profile without interruption and to prevent that debris originating from further handling of the profile enters the inner chamber. In this way an optimal insulation of the frame by the foam is assured.

In case the thermal bridge itself defines an inner chamber, the foam strip can be inserted and expanded before the thermal bridge is connected to the inner and outer shells 2, 3 of the profile. Otherwise, it is also possible to insert the strip in the inner chamber of the profile or the thermal bridge, to size the profile and assemble the frame of a door or window, and to heat the sized profile or frame above Tg of the foam to expand said foam. In this case, heating of the frame can be combined with the production step of drying a lacquer or powder coating provided in the frame. In case handling of the profile is envisaged after insertion of the compressed strip 10 and before expansion thereof, it is preferred to provide an adhesive layer or adhesive strips between the compressed foam and one side wall of the inner chamber in order to allow fixation of the strip and thus to avoid accidental displacement of the foam strip before foam expansion.

Once expanded, the foam strip will remain in place due to friction with the walls of the inner chamber and one can guarantee that substantially the entire inner chamber is filled with foam, thereby assuring thermal insulation, damping and sound insulation properties.

In another embodiment of the present invention the present invention allows for providing alternative profile structures having different choice of selection of materials, wall thickness of the profiles and/or design of single or multiple chamber profile cross sections. Hence, efficient and cost effective optimization of profiles is obtained.

It is clear that the above described profile can be applied in a broad range of structures such as support structures of for example wall panels and containers or as support structures in automotive and aeronautic applications. The present invention is by no means limited to the embodiments described above and represented in the accompanying figures. On the contrary, such a plug for sealing an opening in a specific structure can be made in various embodiments while remaining within the scope of the invention.

Claims

1 Door or window comprising a frame profile, the frame profile (1 ) comprising a foamed insert (9), characterized in that said foam is shape memory polymer foam.

2. The door or window according to claim 1 , wherein the frame profile comprises walls defining an inner chamber (7, 8) wherein said foam is inserted and wherein substantially the entire outer surface of the foam insert (9) contacts the inner surface of said inner chamber (7, 8).

3. The door or window according to claim 1 , wherein the foam is polyurethane foam.

4. The door or window according to claim 1 , wherein the foam has a Tg (glass temperature) above 20°C.

5. The door or window according to claim 4, wherein the foam has a Tg ranging between 30°C and 120°C, preferably between 30°C and 70°C, more preferably between 40°C and 60°C and even most preferably between 50°C and 55°C.

6. The door or window according to claim 1 , wherein the foam is an open cell foam.

7. The door or window according to claim 7, wherein the cell diameter is in the range of about 10Όμιτι to δΟΌμιτι or lower.

8. The door or window according to claim 1 , wherein the foam is a hydrophobic foam.

9. The door or window according to claim 1 , wherein the polymer foam has a density ranging between 20 kg/m³ and 800 kg/m³, preferably between 25 kg/m³ and 200 kg/m³, when in an expanded state.

10. A kit of parts comprising a frame profile having an inner chamber (7, 8) and a shape memory polymer foam strip (10), the foam thereof having a Tg above 20°C.

1 1 . The kit of parts according to claim 10, wherein the foam strip (10) is compressed to a cross section dimension (height or width or both) which is smaller than the cross section dimensions (height or width of both) of the inner chamber (7, 8) of the profile (1 ).

12. Method for the manufacturing of a door- or window profile comprising a shape memory polymer foam comprising the steps of:

(a) compressing said foam (9) to a cross section dimension (height or width or both) smaller than the cross section dimensions (height or width or both) of the chamber (7, 8) of the profile (1 );

(b) transferring said compressed foam obtained by step (a) into the chamber (7, 8) of said profile;

(c) expanding the foam (9) within the chamber (7, 8) of said profile.

13. The method according to claim 13, wherein transferring the compressed foam (10) includes conducting and/or inserting the compressed foam in the profile (1 ).

14. The method according to claim 13, wherein conducting and inserting the compressed foam in the profile is done directly upon compressing.