Insulation panel and method for manufacturing an insulation panel

Abstract

In the method for manufacturing a polyurethane or polyisocyanurate foam insulation panel (1) having closed cells (4), two facers (5, 6) are fed in a vertical orientation through a production line (3). A liquid foam formulation (8) that comprises at least polyol and polyisocyanate is deposited between the two vertically oriented facers. The insulation panel is obtained in the production line with the two facers oriented vertically and parallel to each other in the production line, with the polyurethane or polyisocyanurate foam (2) between the two facers and with the foam adhering to both facers.

Description

[0001] Insulation panel and method for manufacturing an insulation panel

[0002] The invention relates to insulation panels made of polyurethane or polyisocyanurate foam having closed cells. The insulation panels have on both sides of the insulation panels a sheet of material known as a facer. The invention further relates to a method for manufacturing insulation panels of this kind.

[0003] W02022 / 047102A1 describes insulation panels of this kind and a method for producing said panels. Different liquid streams of a foam formulation are applied to a facer in parallel to one another. The liquid foam formulation comprises a polyol and a diisocyanate. The reaction of the polyol and the diisocyanate results in the formation of a closed-cell foam. A second facer is positioned thereabove a distance apart from the expanding foam. The entirety is guided through an oven, where the chemical reactions proceed further, resulting in the formation of a foam insulation panel having closed foam cells and a facer both on the bottom and on the top.

[0004] Insulation panels of this kind are currently used in construction for the thermal insulation of outside walls, floors, and roofs.

[0005] The thermal insulation values of panels of this kind are expressed by lambda (I) values, in W / (m*K).

[0006] W02020 / 076539A1 describes a formulation for producing rigid polyurethane foam. The foam formulation comprises a polyol composition that, relative to the total mass of the polyol composition, comprises more than 70% of at least one polyester polyol having an average hydroxyl value of between 150 and 300 mg KOH / g and an average functionality of at least 2. The formulation comprises a blowing agent that comprises water and an additional blowing agent, a silicone copolymer surfactant, and between 1% and 5% by weight relative to the polyol composition of a cyclic siloxane that at 25°C has a surface tension of less than 21 dynes / cm. The weight ratio of the cyclic siloxane to the silicone copolymer surfactant is between 0.6 and 2.27. The foam formulation comprises a catalyst and optionally a flame retardant. The foam formulation comprises a polyisocyanate having an isocyanate index of between 180 and 500. The foam formulation can be used for producing rigid foam insulation panels that have better thermal insulation values.

[0007] It is an object of the invention to improve the insulation values of insulation panels made of polyurethane foam or of polyisocyanurate foam.

[0008] The first aspect of the invention relates to a method for manufacturing a polyurethane (PUR) or polyisocyanurate (PIR) foam insulation panel having closed cells. The method comprises the steps of:

[0009] - infeeding into a production line two facers, the two facers being fed in a vertical orientation through the production line;

[0010] - depositing a liquid foam formulation that comprises at least polyol and polyisocyanate;

[0011] - expanding the foam formulation in a primarily vertical manner between the two - preferably parallel - vertically oriented facers; wherein the insulation panel is obtained in the production line with the two facers oriented vertically and parallel to each other in the production line, with the polyurethane or polyisocyanurate foam between the two facers and with the foam adhering to both facers.

[0012] The method according to the invention has the advantage of affording insulation panels having better thermal insulation values, i.e. insulation panels having lower lambda (I) values. This is on account of the foam cells becoming elongated in the vertical direction on the production line. This means that the closed cells in the insulation panel are oriented with their longest axis parallel to the facers, rather than perpendicular as is the case in prior art insulation panels. As a result, there are more cells in the direction perpendicular to the panel (direction perpendicular to the facers), and this ensures better thermal insulation. The liquid foam formulation can be deposited in front of the facers or between the vertically oriented facers.

[0013] Preferably, the liquid foam formulation is deposited on a surface.

[0014] In a preferred embodiment, the liquid foam formulation is deposited on a surface that is covered with a strip. More preferably, this strip is a paper strip. The strip is preferably integrated into the insulation panel such that the strip forms a lateral side of the insulation panel. Lateral side refers here to a side located between the large sides of the insulation panel that are covered with the facers.

[0015] The strip can be cut away or machined away when cutting the panel to size or when machining coupling parts on the lateral sides.

[0016] The strip may lie on a moving belt such that the strip is continuously fed through the production line.

[0017] In a preferred embodiment, the liquid foam formulation is deposited on a surface that is covered with a release agent, such that in the method no adhesion occurs between the foam formulation and the surface. More preferably, this is the surface that is guided through the production line. The liquid foam formulation can for example be deposited on a continuously moving belt that is covered with a release agent.

[0018] These embodiments have the advantage that no additional strip is needed - the strip that would be adhering to a lateral side of the panel but contributes nothing functionally to the insulation panel.

[0019] In a preferred embodiment, the surface on which the liquid foam formulation is deposited is continuously fed through the production line. More preferably, this occurs by means of a drive. A preferred embodiment is characterized in that the liquid foam formulation is deposited on a surface having a groove in the direction of production of the production line such that, on said surface, part of the closed-cell foam forms in the groove and part of the closed-cell foam forms alongside the groove.

[0020] This embodiment has the advantage that, during continuous production, a tongue is already being formed at one edge of the insulation panel. This has the advantage that less material or no material at all needs to be machined away in order to form a tongue. This means savings on materials. Said tongue can optionally then undergo post-machining to obtain its final form and dimensions having the desired tolerances. In this postmachining, only a limited amount of material needs to be machined away. The tongue is useful in order to be able to couple panels together by means of a groove on another such insulation panel.

[0021] The liquid foam may here be laid entirely in the groove and the entire required width of the surface wetted by the overflow from the groove. It is also possible for part of the liquid foam to be deposited in the groove and part to be deposited alongside it. It is also possible to deposit the liquid foam alongside the groove, whereby part of it flows into the groove.

[0022] A preferred embodiment is characterized in that an upper surface on the production line delimits the height of the vertical expansion of the foam formulation.

[0023] This embodiment provides a means of defining the dimension of the insulation panel in the vertical direction on the production line.

[0024] More preferably, the upper surface is continuously guided through the production line. More preferably, this occurs without driving said upper surface, but driven by the continuous movement of the foam through the production line. Alternatively, the upper surface can be continuously guided through the production line by means of a drive.

[0025] For example, it is possible that the drive of a double belt of a double-belt oven, wherein the belts of the double-belt oven feed the two facers in a vertical orientation and parallel to each other through the double-belt oven, also provides the driving that continuously guides the upper surface through the production line.

[0026] The upper surface may have a second strip, preferably a second paper strip, positioned between the two facers and on the top side of the vertically oriented facers, such that the top of the expanded foam adheres to the second strip.

[0027] The second strip ensures the upper delimitation of the foam on the production line.

[0028] The second strip can be cut away or machined away when cutting the panel to size or when machining coupling parts on the lateral sides.

[0029] The upper surface may be covered with a release agent, such that in the method no adhesion occurs between the foam formulation and the upper surface. This embodiment has the advantage that no additional strip is needed - the strip that would be adhering to a lateral side of the panel but contributes nothing functionally to the insulation panel.

[0030] A preferred embodiment of the invention is characterized in that the fiber time (tfiber) is reached after the expansion of the foam has reached at least 80%, preferably at most 90%, of the final height of the expanded foam. This ensures optimal forming of the foam. Under these conditions, the foam cells formed still have sufficient elasticity - since polymerization is still taking place only to a limited extent - until the expansion of the foam has reached full height, with the result that the cell walls are properly formed in the foam.

[0031] If the fiber time were to be reached at lower expansion of the liquid foam formulation, the foam would have to expand further in a state in which a significant degree of polymerization has already occurred. At such a significant degree of polymerization, the cells have more brittle walls and there is the risk that further expansion will cause the cells to fracture. This is disadvantageous for the properties of the foam that is formed. The heat evolved by the exothermic polymerization reaction causes a certain degree of further expansion of the foam. If the fiber time is reached once the expansion of the foam is too high or the full height has already been reached, space constraints may mean there is inadequate scope for such further expansion and the risk that such expansion could cause fracture of the foam cells.

[0032] The fiber time (tfiber) is the time interval between the time of deposition of the liquid foam formulation and the time at which polymerization occurs in the foam as a result of the formation of urethane linkages through the reaction of hydroxyl groups with isocyanate groups.

[0033] In addition to the fiber time, the cream time (tcream) is also of importance in the production of polyurethane and polyisocyanurate insulation panels. The cream time is defined as the time interval between the time of deposition of the liquid foam formulation and the start of expansion of the foam. The expansion of the foam occurs through the formation of carbon dioxide (through the reaction of water with isocyanate groups) and through the presence of blowing agents (for example pentane) in the liquid foam formulation.

[0034] The fiber time and the cream time of a liquid foam formulation depend on the specific foam formulation, inter alia the catalysts used and the amount of catalysts.

[0035] Liquid foam formulations for use in the invention always have a cream time that is lower than the fiber time.

[0036] A preferred embodiment of the method of the invention is characterized in that the production line includes a double-belt oven, wherein the belts of the double-belt oven feed the two facers in a vertical orientation and parallel to each other through the doublebelt oven and wherein, in the oven, the polymerization of the foam formulation occurs between the two facers, with the foam that has formed adhering to the two facers.

[0037] The oven ensures proper adhesion of the foam to the two facers. Proper adhesion of the foam to the two facers makes it possible, by means of the double belt of the double-belt oven, for the facers to be able to be unwound from their respective rolls without the need for an active drive for these rolls. This also allows the surface on which the liquid foam formulation is deposited and the upper surface to be moved together without the need for a separate drive.

[0038] It is preferable that on the production line the expanded foam between the two facers reaches a height in the vertical direction in relation to the production line of at least 250 mm, more preferably at least 550 mm, more preferably at least 850 mm, and more preferably at least 1150 mm in height.

[0039] It is preferable that on the production line the expanded foam between the two facers reaches a height in the vertical direction in relation to the production line of 300 mm, more preferably of 600 mm, more preferably of 900 mm, and more preferably of 900 mm in height.

[0040] In a preferred embodiment, the liquid foam formulation is deposited in the form of a curtain across the width.

[0041] In a preferred embodiment, one stream of liquid foam formulation is deposited that flows out and in doing so spreads across the entire width.

[0042] In a preferred embodiment, multiple streams of liquid foam formulation are deposited across the width.

[0043] A preferred embodiment of the method of the invention is characterized in that on the production line a backflow of the foam occurs at the top of the foam during the expansion of the foam, with the result that at the top of the foam that has formed, viewed on the production line, there are foam cells present in an orientation that is angled upward and toward the infeed side of the production line. Such an embodiment can occur as a result of slight overfilling with liquid foam. Upon expansion of the foam, this results in the foam touching the upper surface of the production line. Overfilling results in this foam being pushed backward; this results in the foam cells that have flowed back having an orientation that is angled upward and toward the infeed side of the production line. The polymerization reaction then freezes these cells in this orientation.

[0044] Such overfilling is desirable in order to ensure that the full height is filled with foam. If only just enough liquid foam formulation were to be deposited, there is the risk of process variations resulting in zones occurring in the insulation panel that are not filled to full height with the foam.

[0045] Since this different orientation according to this embodiment occurs only locally at an edge of the insulation panel formed, it will not always be detectable when using the insulation panels. This is because the insulation panels are still cut to the desired size and coupling parts machined, during which these cells with a different orientation are completely or partially removed.

[0046] A preferred embodiment of the invention is characterized in that the liquid foam formulation comprises at least:

[0047] - a polyester polyol, the polyester polyol preferably having a hydroxyl value of between 150 and 600 mg KOH / g and a functionality of at least 2;

[0048] - a polyisocyanate, preferably a polymeric methylene diphenyl diisocyanate (pMDI);

[0049] - a blowing agent, the blowing agent comprising water and an additional blowing agent, for example pentane;

[0050] - a surfactant, for example a silicone surfactant and / or a non-silicone surfactant;

[0051] - a catalyst;

[0052] - optionally additives, for example flame retardant additives; wherein the polyisocyanate is present in the foam formulation in an amount such that the foam formulation has an isocyanate index of more than 180 and preferably of less than 450. This is a foam formulation for manufacturing a polyisocyanurate insulation panel according to the method of the invention. The high excess of polyisocyanate in relation to hydroxyl groups in the foam formulation is to ensure the formation of large numbers of isocyanurate groups in the foam.

[0053] The isocyanate index is calculated by dividing the number of isocyanate groups in the liquid foam formulation by the number of isocyanate-reactive hydrogen atoms in the liquid foam formulation (including not just those of the polyol, but also those present in isocyanate-reactive blowing agents such as water) and multiplying this ratio by 100.

[0054] In such a liquid foam formulation, the polyester polyol and the polyisocyanate together preferably make up at least 85% by weight, more preferably at least 90% by weight, and more preferably less than 92% by weight, of the liquid foam formulation.

[0055] A preferred embodiment of the invention is characterized in that the liquid foam formulation comprises at least:

[0056] - a polyol, the polyol preferably having a hydroxyl value of between 150 and 600 mg KOH / g and a functionality of at least 2, preferably of at least 3, more preferably of at least 4;

[0057] - a polyisocyanate, preferably a polymeric methylene diphenyl diisocyanate (pMDI);

[0058] - a blowing agent, the blowing agent preferably comprising water and an additional blowing agent, for example pentane;

[0059] - a surfactant, for example a silicone surfactant and / or a non-silicone surfactant;

[0060] - a catalyst;

[0061] - optionally additives, for example flame retardant additives; wherein the polyisocyanate is present in the foam formulation in an amount such that the foam formulation has an isocyanate index of more than 105 and preferably of less than 130.

[0062] This is a foam formulation for manufacturing a polyurethane insulation panel according to the method of the invention. As a consequence of the amount of polyisocyanate in relation to polyol, it is mainly urethane linkages that are formed in the foam, isocyanurate groups being formed only in a small and insignificant amount. This is also because urethane linkages are formed at a faster rate than isocyanurate groups.

[0063] The polyol may preferably comprise at least polyether polyol, and more preferably to an extent of more than half by mass.

[0064] Preferably, the liquid foam formulation that is deposited has a viscosity measured at 25°C of between 165 and 2200 mPa.s. This refers to the emulsion viscosity of the liquid foam that is deposited. Such viscosity values ensure the easy handling and deposition of the liquid foam formulation.

[0065] More preferably, the liquid foam formulation that is deposited has a viscosity measured at 25°C of more than 900 mPa.s and preferably less than 1800 mPa.s, more preferably less than 1700 mPa.s. Such viscosity ensures greater resistance to deformation of the foam in the liquid phase. This results in the formation of foam having a lower lambda value and thus foam having better thermal insulation properties.

[0066] In a preferred embodiment of the invention, the continuously produced insulation panel is cut to length in the production line. To this end, the production line may include a cutting unit.

[0067] Such embodiments have the advantage that the panels can be cut to length directly without the need for (manual) material pretreatment.

[0068] More preferably, the insulation panel, after it has been cut to length, is turned by 90° so that it is lying horizontally. This facilitates the further transport and treatment of the insulation panel.

[0069] The facer may be or comprise an aluminum sheet. The aluminum sheet preferably has a thickness of more than 30 micrometers, more preferably of more than 40 micrometers, and more preferably of less than 105 micrometers, more preferably of less than 75 micrometers. The facer may be a laminate. This laminate may preferably comprise:

[0070] - a plastic film, preferably on the outside of the laminate and preferably for forming the outer surface of the insulation panel;

[0071] - one or more aluminum sheets, each aluminum sheet preferably being at least 4 micrometers thick and preferably being less than 20 micrometers thick; and

[0072] - one or more layers of paper, preferably layers of kraft paper.

[0073] The plastic film may preferably be a polyethylene film, a polyurethane film or a polyvinylidene film.

[0074] In a preferred embodiment of the method of the invention, the thickness of the insulation panel is at least 20 mm, more preferably at least 40 mm, more preferably at least 60 mm, more preferably at least 100 mm, preferably at least 180 mm, more preferably at least 350 mm. The method according to the first aspect of the invention makes it possible to make insulation panels having higher thickness than via the methods described in the prior art, methods such as described in W02022 / 047102A1.

[0075] The foam of the insulation panel produced preferably has a density of between 20 and 40 kg / m3, more preferably of between 27 and 35 kg / m3.

[0076] The second aspect of the invention relates to an insulation panel. The insulation panel comprises a polyurethane or polyisocyanurate foam having closed cells between two parallel facers. The longest axis of the closed cells forms an angle with the two facers of between 80° and 100°, preferably between 85° and 95°, more preferably between 87° and 92°.

[0077] The orientation of the closed foam cells where the longest axis forms an angle with the two facers of between 80° and 100° ensures that there are more cells in the thickness direction of the insulation panel. This provides the insulation panel with better thermal insulation values, as expressed by a lower lambda value for the insulation panel. The orientation of the closed cells - and their dimensions - can be determined by SEM (scanning electron microscopy). This can be done after making microtome cuts in the foam. It is possible to make microtome cuts at different angles to the facers. Microtome cuts can be made for different angles to the facers. In each of these cuts, the longest axis can be measured from the two-dimensional cross section of the three-dimensional cell. Thus, the angle of the cut can be determined where the longest axis of the two- dimensional cross section is greatest. This angle is therefore the angle that the longest axis of the closed cells forms with the two facers.

[0078] The two facers preferably form the two large parallel surfaces of the insulation panel.

[0079] Insulation panels according to the second aspect of the invention can be obtained by applying the method of the first aspect of the invention.

[0080] Preferably, the closed cells of the insulation panel essentially form a prolate spheroid.

[0081] In the formation of closed polyurethane foam or closed polyisocyanurate foam, dodecahedral cells are in theory formed. However, this is theoretically so when the expansion of the foam has equal opportunity for expansion in the three directions perpendicular to one another. In the case of the invention, the expansion of the foam does not occur equally in all directions. The shape of the closed foam cells can accordingly approximate best to a prolate spheroid. A prolate spheroid is the body obtained when rotating an ellipse about its longest axis.

[0082] A preferred insulation panel is characterized in that the number-average length of the shortest axis of the closed cells divided by the length of the longest axis of the closed cells is less than 0.7, more preferably less than 0.5, more preferably less than 0.4, more preferably less than 0.3; and preferably higher than 0.25.

[0083] Lower values for the number-average length of the shortest axis of the closed cells divided by the length of the longest axis of the closed cells have the advantage that the lambda value of the insulation panels is lower. This means that the insulation panel provides better thermal insulation.

[0084] The ratio between the length of the shortest axis divided by the length of the longest axis is preferably not too low, since this can adversely affect the compressive strength in the thickness direction of the insulation panel.

[0085] A preferred embodiment of the second aspect of the invention is characterized in that the longest axis of the closed cells forms an angle of between 85° and 95° with a transverse section of the insulation panel, the longest axis of the closed cells preferably having a substantially perpendicular orientation on a transverse section of the insulation panel.

[0086] Such an embodiment, as a result of the orientation of the closed cells, ensures a good thermal insulation value.

[0087] An insulation panel of preference is characterized in that the longest axis of the closed foam cells on a second lateral side of the panel produced is oriented parallel to the two facers making up the top and bottom surfaces of the panel and forms an angle with the axis of the panel, this angle preferably being between 10° and 80°; this angle preferably being between 20° and 70°. The orientation of the closed foam cells may differ in this way from the orientation of the foam cells in the bulk of the insulation panel. This may be caused when overfilling with liquid foam is used in the production of the insulation panel according to the method of the first aspect of the invention. In this case, expanded foam cells are pushed backward, resulting in these cells adopting an orientation different to that of the bulk of the cells and being fixed in this orientation when polymerization occurs.

[0088] The two parallel facers of the panel of the invention may each be or comprise an aluminum sheet. The aluminum sheet preferably has a thickness of more than 30 micrometers, more preferably of more than 40 micrometers, and more preferably of less than 105 micrometers, more preferably of less than 75 micrometers. The facers of the panel of the invention may each comprise or consist of a laminate. An example of a laminate that can be used in the invention comprises a plastic film, one or more aluminum sheets, and one or more layers of paper.

[0089] The plastic film is preferably provided on the outside of the laminate and preferably forms the outer surface of the insulation panel.

[0090] The plastic film may for example be a polyethylene film, a polyurethane film or a polyvinylidene film.

[0091] The one or more aluminum sheets are each preferably at least 4 micrometers thick and preferably less than 20 micrometers thick.

[0092] The one or more layers of paper are preferably layers of kraft paper.

[0093] The insulation panel is preferably at least 20 mm thick, more preferably at least 40 mm thick, more preferably at least 60 mm thick, more preferably at least 100 mm thick, preferably at least 180 mm thick, more preferably at least 350 mm thick.

[0094] The insulation panel preferably has a density of between 20 and 40 kg / m3, more preferably of between 27 and 35 kg / m3. Such insulation panels offer good insulation values in conjunction with good compressive strength both in the thickness direction of the panel and in the length and width directions of the panel.

[0095] The third aspect of the invention is a production line for carrying out a method as in any embodiment of the first aspect of the invention. The production line comprises

[0096] - a first infeed unit for infeeding a first facer, the first facer being fed through the production line in a vertical orientation;

[0097] - a second infeed unit for infeeding a second facer, the second facer being fed through the production line in a vertical orientation;

[0098] - a unit for depositing a liquid foam formulation that comprises at least polyol and polyisocyanate; - an oven, the oven being provided for the polymerization of the foam formulation between the first facer and the second facer;

[0099] - a transport entity for feeding the first facer and the second facer through the oven vertically and parallel to each other with the foam formulation between the first facer and the second facer.

[0100] The production line according to the third aspect of the invention can be used for the production of an insulation panel according to the second aspect of the invention.

[0101] A preferred production line is characterized in that the production line includes a unit for introducing a strip, wherein the liquid foam formulation can be deposited on the strip, preferably such that the strip is integrated into the insulation panel, the strip forming a lateral side of the insulation panel on the production line.

[0102] A preferred embodiment of the production line is characterized in that the production line includes a continuously moving surface provided for the deposition thereon of the continuous liquid foam formulation, the continuously moving surface being covered with a release agent, such that in the method no adhesion occurs between the foam formulation and the surface.

[0103] This continuously moving surface may for example be an endless belt covered with a release agent.

[0104] The production line preferably includes a second continuously moving surface provided so as to limit the height of the vertical expansion of the foam formulation in the production line.

[0105] This continuously moving second surface may for example be an endless belt covered with a release agent. In a preferred embodiment, the production line includes a unit for introducing a second strip, preferably a second paper strip, the second paper strip being provided so as to limit the height of the vertical expansion of the foam formulation in the production line.

[0106] The second continuously moving surface is preferably covered with a release agent, such that in the method no adhesion occurs between the foam formulation and this second continuously moving surface.

[0107] The oven is preferably a double-belt oven, wherein the belts of the double-belt oven are provided for feeding the two facers through the double-belt oven in a vertical orientation and parallel to each other such that, in the oven, the polymerization of the foam formulation is able to occur between the two facers, with the foam that has formed being able to adhere to the two facers.

[0108] The unit for depositing a liquid foam formulation may be configured so as to deposit the liquid foam formulation in the form of a curtain across the width.

[0109] The unit for depositing a liquid foam formulation may be configured so as to deposit the liquid foam formulation in the form of one stream of liquid foam formulation that flows out and in doing so is able to spread across the entire width.

[0110] The unit for depositing a liquid foam formulation may be configured so as to deposit multiple streams of liquid foam formulation across the width.

[0111] The production line preferably includes a cutting unit for cutting the continuously produced insulation panel to length.

[0112] More preferably, the production line includes an apparatus for turning the insulation panel by 90° after it has been cut to length, so that it is lying horizontally. With the intention of better illustrating the features of the invention, some preferred embodiments are described below by way of example without these being limiting in character and with reference to the appended drawings, in which:

[0113] Figures 1 and 2 illustrate an example of a production line according to the invention;

[0114] Figure 3 shows a detail of an embodiment of a production line according to the invention in the view F3 of Figure 1;

[0115] Figure 4 shows an example of an insulation panel according to the invention; Figures 5 and 6 show details of the insulation panel from Figure 4;

[0116] Figure 7 shows the insulation panel from Figure 4 after coupling parts have been machined; and

[0117] Figure 8 shows a detail according to view F8 of the insulation panel from Figure 4.

[0118] Figure 1 illustrates an example of a production line 3 according to the second aspect of the invention. Figure 2 shows a cross section of the production line from Figure 1 in side view as indicated by F2 in Figure 1. This production line can be used for carrying out the method according to the first aspect of the invention. Figures 1 and 2 thus likewise illustrate a method according to the first aspect of the invention.

[0119] The production line 3 includes a first infeed unit for infeeding a first facer 5. This first facer is fed through the production line in a vertical orientation. A second infeed unit is provided for infeeding a second facer 6, the second facer being fed through the production line in a vertical orientation.

[0120] A unit 32 is provided for depositing a liquid foam formulation 8 that comprises at least polyol and polyisocyanate. In the example, this unit for depositing a liquid foam formulation is configured so as to deposit the liquid foam formulation 8 in the form of a curtain across the width. Other embodiments are however also possible. As shown in Figure 2, the production line in the example includes a unit 29 for introducing a paper strip 12 on the surface 10 on which the liquid foam formulation 8 is deposited. The liquid foam formulation 8 is deposited on the paper strip 12. This paper strip 12 is integrated into the insulation panel, the paper strip forming a lateral side 13 of the insulation panel on the production line. This paper strip can be removed when cutting the insulation panels to size and / or when machining coupling parts on the insulation panel.

[0121] By means of a drive, the surface 10 on which the liquid foam formulation 8 is deposited can be continuously fed through the production line 3.

[0122] The production line 3 includes a second continuously moving surface 17 provided so as to limit the height of the vertical expansion of the foam formulation in the production line.

[0123] As shown in Figure 2, the production line 3 in the example includes a unit 30 for introducing a second paper strip 19. This second paper strip 19 delimits the height of the vertical expansion of the foam formulation 8 in the production line.

[0124] The second paper strip 19 is positioned between and on the top side of the two vertically oriented facers 5, 6. The expanded foam is able to adhere to this second strip 19.

[0125] For the clarity of the figure, Figure 1 does not show the units 29, 30 for introducing the paper strip 12 and for introducing the second paper strip 19.

[0126] The production line 3 includes a double-belt oven 21. This oven 21 is provided for the polymerization of the foam formulation between the first facer 5 and the second facer 6.

[0127] The belts 22, 23 of the double-belt oven 21 are vertically oriented and are provided for feeding the two facers 5, 6 through the double-belt oven in a vertical orientation and parallel to each other such that the polymerization of the foam formulation 8 in the oven 21 is able to occur between the two facers, with the foam that has formed being able to adhere to the two facers 5, 6.

[0128] When using this production line, an insulation panel 1 is obtained with the two facers 5, 6 are oriented vertically and parallel to each other in the production line 3, with the polyurethane or polyisocyanurate foam 2 between the two facers 5, 6 and with the foam adhering to both facers 5, 6. The panel 1 formed has a thickness T. The panel 1 formed likewise has two lateral sides 13, 14.

[0129] Figure 2 illustrates the expansion of the liquid foam formulation 8 from the deposition of said liquid foam formulation until the foam reaches the delimited height H as a result of expansion between the two facers 5, 6. Figure 2 shows this expansion, with the facer 5 omitted so as to be able to show the expansion in progress. From the time of deposition of the liquid foam formulation 8, the cream time (ti) and the fiber time (t2) are important. The cream time (ti) is the time from which expansion of the liquid foam formulation 8 commences. The fiber time (ti) is the time from which polymerization commences in the foam as a result of the formation of urethane linkages through the reaction of hydroxyl groups with isocyanate groups. In the example shown, the process parameters for the production line (including the production speed of the production line and the formulation of the liquid foam) are set such that the foam has a fiber time (t2) that is achieved when the liquid foam has expanded to a height Hi equal to 85% of the delimited height H to which the foam expands in the production line.

[0130] In the example, the amount of liquid foam formulation 8 deposited is such that, if the expansion were not height-limited, the expansion of the foam would be higher than the delimited expansion height H on the production line. The foam is thus present in a certain excess amount. This results in the still-expanding foam undergoing a certain degree of backflow upon contact of the expanding foam with the upper surface 17. At the top of the foam that has formed - viewed on the production line - there may as a result be foam cells 25 present in an orientation that is angled upward and toward the infeed side of the production line. The longest axis of these foam cells 25, which is substantially parallel to the two facers 5, 6, forms an angle A2 with the vertical direction on the production line 3.

[0131] The production line 3 in Figure 1 includes a cutting unit 27 for cutting the continuously produced insulation panel 1 to length.

[0132] Figure 3 shows a detail of an embodiment of a production line according to the invention in the view F3 of Figure 1. In the example in Figure 3, the surface 10 on which the liquid foam formulation 8 is deposited has a groove 15 in the direction of production such that, on said surface 10, part of the closed-cell foam forms in the groove 15 and part of the closed-cell foam forms alongside the groove. This makes it possible for a tongue already to be formed on the production line that may need to undergo subsequent post-machining in order to achieve the desired tolerances. This permits optimization of material consumption.

[0133] It is however also possible for the surface 10 on which the liquid foam formulation 8 is deposited to be flat.

[0134] Figure 4 shows an example of an insulation panel 1 according to the invention. This insulation panel 1 can be produced according to the method of the first aspect of the invention on a production line according to the second aspect of the invention. The insulation panel 1 comprises a polyurethane or polyisocyanurate foam 2 having closed cells 4 between two parallel facers 5, 6. The panel further has two lateral sides 13, 14. The insulation panel has a thickness T.

[0135] The closed cells 4 essentially form a prolate spheroid.

[0136] The dashed lines 44 in Figure 4 show where coupling parts are to be machined.

[0137] Figures 5 and 6 show details of the insulation panel from Figure 4. Figure 5 shows a detail of a cell according to view V-V from Figure 4. Figure 6 shows a detail of a cell according to view VI- VI from Figure 4. The longest axis 38 (which has a number-average length Tl) of the closed cells forms an angle Al essentially equal to 90° with the transverse section of the insulation panel. This longest axis is thus perpendicular to the transverse section of the insulation panel. This longest axis 38 is thus essentially parallel to the two facers 5, 6.

[0138] In the example, the number-average length T2 of the shortest axis 39 of the closed cells divided by the length Tl of the longest axis of the closed cells is less than 0.7.

[0139] As shown in Figure 6, which shows the view according to VI- VI of a cell of the foam, the cell in this view has dimensions T2 and T3 according to the axes of the foam cell in this view.

[0140] If overfilling occurs during production of the insulation panel, as is explained in the description of the production line and the method in Figure 2, the longest axis 40 of the closed foam cells 25 on a second lateral side 14 of the panel produced is oriented parallel to the two facers 5, 6 and forms an angle A2 with the axis 42 of the panel; this angle A2 can be between 10° and 80°. This is illustrated in Figure 8, which is a detail view according to F 8 of the panel from Figure 4.

[0141] Figure 7 shows the insulation panel 1 from Figure 4 after coupling parts have been machined. The reference numerals in Figure 7 are as defined in Figure 4. The dashed lines 44 in Figure 4 show where the coupling parts are to be machined. Machining operations have provided the insulation panel 1 with coupling parts in the form of a tongue 35 and a groove 36.

[0142] Tests have demonstrated that polyisocyanurate insulation panels according to the invention have a lambda (I) value that is at least 10% lower than that of insulation panels with a similar liquid foam formulation made according to conventional production methods. The different orientation of the foam cells in the panel provides this better thermal insulation. The present invention is in no way limited to the embodiments described hereinabove, however the insulation panels and the method may be realized in different variants without departing from the scope of the present invention.

Claims

Claims.1 Method for manufacturing a polyurethane (PUR) or polyisocyanurate (PIR) foam (2) insulation panel (1) having closed cells (4), the method comprising the steps of:- infeeding into a production line (3) two facers (5, 6), the two facers being fed in a vertical orientation through the production line;- depositing a liquid foam formulation (8) that comprises at least polyol and polyisocyanate;- expanding the foam formulation in a primarily vertical manner between the two - preferably parallel - vertically oriented facers (5, 6); wherein the insulation panel (1) is obtained in the production line with the two facers (5, 6) oriented vertically and parallel to each other in the production line (3), with the polyurethane or polyisocyanurate foam between the two facers (5, 6) and with the foam adhering to both facers (5, 6).2.- Method as in claim 1, characterized in that the liquid foam formulation (8) is deposited on a surface (10).3.- Method as in claim 2, characterized in that the surface (10) on which the liquid foam formulation (8) is deposited is covered with a strip (12), preferably a paper strip, the strip preferably being integrated into the insulation panel (1) such that the strip forms a lateral side (13) of the insulation panel.4.- Method as in claim 2, characterized in that the surface (10) on which the liquid foam formulation is deposited is covered with a release agent, such that in the method no adhesion occurs between the foam formulation and the surface, the surface preferably being guided through the production line.5.- Method as in any of the preceding claims 2-4, characterized in that the surface (10) on which the liquid foam formulation (8) is deposited is continuously fed through the production line (3), preferably by means of a drive.6.- Method as in any of the preceding claims, characterized in that the liquid foam formulation (8) is deposited on a surface (10) having a groove (15) in the direction of production of the production line (3) such that, on said surface (10), part of the closedcell foam forms in the groove (15) and part of the closed-cell foam forms alongside the groove.7.- Method as in any of the preceding claims, characterized in that an upper surface (17) on the production line delimits the height of the vertical expansion of the foam formulation, the upper surface preferably being continuously guided through the production line.8.- Method as in claim 7, characterized in that the upper surface (17) has a second strip (19), preferably a second paper strip, positioned between the two facers (5, 6) and on the top side of the vertically oriented facers, such that the top of the expanded foam adheres to the second strip (19).9.- Method as in claim 7, characterized in that the upper surface is covered with a release agent, such that in the method no adhesion occurs between the foam formulation and the upper surface.10.- Method as in any of the preceding claims 7-9, characterized in that the fiber time (tfiber) is reached after the expansion of the foam has reached at least 80%, preferably at most 90%, of the final height (H) of the expanded foam.11.- Method as in any of the preceding claims, characterized in that the production line (3) includes a double-belt oven (21), wherein the belts (22, 23) of the double-belt oven feed the two facers (5, 6) in a vertical orientation and parallel to each other through the double-belt oven and wherein, in the oven, the polymerization of the foam formulation occurs between the two facers, with the foam that has formed adhering to the two facers.12.- Method as in any of the preceding claims, characterized in that on the production line (3) the expanded foam between the two facers (5, 6) reaches a height (H) in the vertical direction in relation to the production line of at least 250 mm, preferably at least 550 mm, preferably at least 850 mm, and more preferably at least 1150 mm.13.- Method as in any of the preceding claims, characterized in that the liquid foam formulation (8) is deposited in the form of a curtain across the width, or in that one stream of liquid foam formulation is deposited that flows out and in doing so spreads across the entire width, or in that multiple streams of liquid foam formulation are deposited across the width.14.- Method as in any of the preceding claims, characterized in that on the production line (3) a backflow of the foam occurs at the top of the foam during the expansion of the foam, with the result that at the top of the foam that has formed, viewed on the production line, there are foam cells (25) present in an orientation that is angled upward and toward the infeed side of the production line.15.- Method as in any of the preceding claims, characterized in that the liquid foam formulation (8) comprises at least:- a polyester polyol, the polyester polyol preferably having a hydroxyl value of between 150 and 600 mg KOH / g and a functionality of at least 2;- a polyisocyanate, preferably a polymeric methylene diphenyl diisocyanate (pMDI);- a blowing agent, the blowing agent comprising water and an additional blowing agent, for example pentane;- a surfactant, for example a silicone surfactant and / or a non-silicone surfactant;- a catalyst;- optionally additives, for example flame retardant additives; wherein the polyisocyanate is present in the foam formulation in an amount such that the foam formulation has an isocyanate index of more than 180 and preferably of less than 450.16.- Method as in claim 15, characterized in that the polyester polyol and the polyisocyanate together make up at least 85% by weight, preferably at least 90% by weight, and more preferably less than 92% by weight, of the liquid foam formulation.17.- Method as in any of the preceding claims 1-14, characterized in that the liquid foam formulation (8) comprises at least:- a polyol, which preferably comprises at least polyether polyol, the polyol preferably having a hydroxyl value of between 150 and 600 mg KOH / g and a functionality of at least 2, and preferably of at least 3, more preferably of at least 4;- a polyisocyanate, preferably a polymeric methylene diphenyl diisocyanate (pMDI);- a blowing agent, the blowing agent comprising water and an additional blowing agent, for example pentane;- a surfactant, for example a silicone surfactant and / or a non-silicone surfactant;- a catalyst;- optionally additives, for example flame retardant additives; wherein the polyisocyanate is present in the foam formulation in an amount such that the foam formulation has an isocyanate index of more than 105 and preferably of less than 130.18.- Method as in any of the preceding claims, characterized in that the liquid foam formulation that is deposited has a viscosity measured at 25°C of between 165 and 2200 mPa.s.19.- Method as in any of the preceding claims, characterized in that the continuously produced insulation panel is cut to length in the production line.20.- Method as in claim 19, characterized in that the insulation panel, after it has been cut to length, is turned by 90° so that it is lying horizontally.21.- Method as in any of the preceding claims, characterized in that the facer (5, 6) is or comprises an aluminum sheet, the aluminum sheet preferably having a thickness ofmore than 30 micrometers, and preferably of less than 105 micrometers, more preferably of less than 75 micrometers.22.- Method as in any of the preceding claims 1-20, characterized in that the facer (5,6) is a laminate, the laminate comprising:- a plastic film, preferably on the outside of the laminate and preferably for forming the outer surface of the insulation panel;- one or more aluminum sheets, each aluminum sheet preferably being at least 4 micrometers thick and preferably being less than 20 micrometers thick; and- one or more layers of paper, preferably layers of kraft paper.23.- Method as in claim 22, characterized in that the plastic film is a polyethylene film, a polyurethane film or a polyvinylidene film.24.- Method as in any of the preceding claims, characterized in that the thickness (T) of the insulation panel is at least 20 mm, preferably at least 40 mm, preferably at least 60 mm, more preferably at least 100 mm, preferably at least 180 mm, more preferably at least 350 mm.25.- Method as in any of the preceding claims, characterized in that the foam of the insulation panel produced has a density of between 20 and 40 kg / m3, preferably of between 27 and 35 kg / m3.26.- Insulation panel, wherein the insulation panel (1) comprises a polyurethane or polyisocyanurate foam having closed cells (4) between two parallel facers (5, 6), characterized in that the longest axis (38) of the closed cells forms an angle (Al) with the two facers of between 80° and 100°, preferably between 85° and 95°, more preferably between 87° and 92°.27.- Insulation panel as in claim 26, wherein the closed cells (4) essentially form a prolate spheroid.28.- Insulation panel as in claim 26 or 27, characterized in that the number-average length (T2) of the shortest axis (39) of the closed cells divided by the length (Tl) of the longest axis (38) of the closed cells is less than 0.7, preferably less than 0.5, preferably less than 0.4, more preferably less than 0.3; and preferably higher than 0.25.29.- Insulation panel as in any of the preceding claims 26-28, characterized in that the longest axis (38) of the closed cells forms an angle (Al) of between 85° and 95° with a transverse section of the insulation panel, the longest axis of the closed cells preferably having a substantially perpendicular orientation on a transverse section of the insulation panel.30.- Insulation panel as in any of the preceding claims 26-29, characterized in that the longest axis (40) of the closed foam cells (4) on a second lateral side (14) of the panel produced is oriented parallel to the two facers (5, 6) and forms an angle (A2) with the axis of the panel, this angle preferably being between 10° and 80°; this angle preferably being between 20° and 70°.31.- Insulation panel as in any of the preceding claims 26-30, characterized in that the two parallel facers (5, 6) each are or comprise an aluminum sheet, the aluminum sheet preferably having a thickness of more than 30 micrometers, and preferably of less than 105 micrometers, more preferably of less than 75 micrometers.32.- Insulation panel as in any of the preceding claims 26-30, characterized in that the facers (5, 6) each comprise or consist of a laminate, the laminate comprising:- a plastic film, preferably on the outside of the laminate and preferably for forming the outer surface of the insulation panel;- one or more aluminum sheets, each aluminum sheet preferably being at least 4 micrometers thick and preferably being less than 20 micrometers thick; and- one or more layers of paper, preferably layers of kraft paper.33.- Insulation panel as in claim 32, characterized in that the plastic film is a polyethylene film, a polyurethane film or a polyvinylidene film.34.- Insulation panel as in any of the preceding claims 26-33, characterized in that the thickness (T) of the insulation panel is at least 20 mm, preferably at least 40 mm, preferably at least 60 mm, more preferably at least 100 mm, preferably at least 180 mm, more preferably at least 350 mm.35.- Insulation panel as in any of the preceding claims 26-34, characterized in that the foam (2) of the insulation panel produced has a density of between 20 and 40 kg / m3, preferably of between 27 and 35 kg / m3.36.- Production line for carrying out a method as in any of the preceding claims 1-25, characterized in that the production line (3) comprises:- a first infeed unit for infeeding a first facer (5), the first facer being fed through the production line in a vertical orientation;- a second infeed unit for infeeding a second facer (6), the second facer being fed through the production line in a vertical orientation;- a unit (32) for depositing a liquid foam formulation (8) that comprises at least polyol and polyisocyanate;- an oven (21), the oven being provided for the polymerization of the foam formulation between the first facer and the second facer;- a transport entity (22, 23) for feeding the first facer (5) and the second facer (6) through the oven (21) vertically and parallel to each other with the foam formulation (8) between the first facer and the second facer.37.- Production line as in claim 36, characterized in that the production line includes a unit (19) for introducing a strip (12), preferably a paper strip, wherein the liquid foam formulation (8) can be deposited on the strip, preferably such that the strip (12) is integrated into the insulation panel such that the strip forms a lateral side (13) of the insulation panel on the production line.38.- Production line as in claim 36 or 37, characterized in that the production line includes a continuously moving surface provided for the deposition thereon of thecontinuous liquid foam, the continuously moving surface being covered with a release agent, such that in the method no adhesion occurs between the foam formulation and the surface.39.- Production line as in any of claims 36-38, characterized in that the production line includes a second continuously moving surface (17) provided so as to limit the height of the vertical expansion of the foam formulation in the production line.40.- Production line as in claim 39, characterized in that the production line includes a unit (30) for introducing a second strip (19), preferably a second paper strip, the second paper strip being provided so as to limit the height of the vertical expansion of the foam formulation in the production line.41.- Production line as in claim 39, characterized in that the second continuously moving surface is covered with a release agent, such that in the method no adhesion occurs between the foam formulation and this second continuously moving surface.42.- Production line as in any of the preceding claims 36-41, characterized in that the oven is a double-belt oven (21), wherein the belts (22, 23) of the double-belt oven are provided for feeding the two facers (5, 6) through the double-belt oven in a vertical orientation and parallel to each other such that, in the oven, the polymerization of the foam formulation is able to occur between the two facers, with the foam that has formed being able to adhere to the two facers.43.- Production line as in any of the preceding claims 36-42, characterized in that the unit for depositing a liquid foam formulation is configured so as to deposit the liquid foam formulation in the form of a curtain across the width, or is configured so as to deposit the liquid foam formulation in the form of one stream of liquid foam formulation that flows out and in doing so is able to spread across the entire width, or is configured so as to deposit multiple streams of liquid foam formulation across the width.44.- Production line as in any of the preceding claims 36-43, characterized in that the production line includes a cutting unit (27) for cutting the continuously produced insulation panel to length. 45.- Production line as in claim 44, characterized in that the production line includes an apparatus for turning the insulation panel by 90° after it has been cut to length, so that it is lying horizontally.

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