Polyurethane / polyisocyanurate foam block for the thermal insulation body of the tank, and its preparation process

Abstract

The present invention relates to a fibrous polyurethane / polyisocyanurate foam block (20), the foam block having two peripheral regions along its thickness E, an upper peripheral region extending from an upper surface of the block to the other, and a lower peripheral region extending from a lower surface of the block, the two regions each occupying less than 20% along the thickness of the block and separated by an intermediate region, the upper and lower peripheral regions being within a range of 2 / 3≦(T f upp. / T f low. )≦3 / 2 fiber density T f upp. and T f low. and the intermediate region has a fiber density T f int. is smaller than the density in the surrounding area, i.e., T f int. <T f upp. , and T f int. <T f low. The present invention relates to a fibrous polyurethane / polyisocyanurate foam block (20) comprising:

Description

[Technical field]

[0001] The subject of the invention is a block of fiber-reinforced polyurethane (PUR) and / or polyisocyanurate (PIR) foam attached to an insulating body. The block must exhibit very specific mechanical and thermal properties depending on the specific application, while being as economical to manufacture as possible. The block of said foam is used in tanks integrated into a membrane structure (also called integral tanks) or in self-supporting / semi-self-supporting tanks of type A, B or C, capable of containing very low temperature fluids, called cryogenic fluids, in particular liquefied natural gas (LNG) or liquefied petroleum gas (LPG), for example. [Background technology]

[0002] More specifically, the present invention relates to a sealed insulated tank using such a foam, a vessel provided with at least one such tank, a loading and unloading process for such a vessel, and a transfer system for liquid products contained on such a vessel.

[0003] The present invention also relates to a process for preparing blocks of such foams from at least one polyisocyanate and at least one polyol.

[0004] Polyurethane PUR foams are cellular insulations consisting of fine cells that store gases that may have low thermal conductivity. PUR foams are used in a great many applications, for example in the automotive industry as flexible PUR foams or in insulation as rigid PUR foams. The formation of polyurethane type foams is well known to those skilled in the art. It involves a multi-component reaction of polyols (compounds with at least two hydroxyl groups), polyisocyanates (compounds with at least two isocyanate-NCO functional groups) and blowing agents, also called "blowing agents". This condensation reaction is catalyzed in particular by compounds with basic and / or nucleophilic properties, for example tertiary amines and metal-carboxylate coordination complexes such as tin salts and bismuth salts. The polyols commonly used for the production of PUR foams are polyether polyols or polyester polyols. Thus, a large number of compounds are required for the formation of PUR foams.

[0005] Polyisocyanurate (PIR) and polyurethane / polyisocyanurate (PUR-PIR) foams are also used in the building industry (construction / renovation) and offer the advantage of offering greater compressive strength as well as better fire resistance properties than PUR. The formation process of these foams is similar to that of PUR foams, since obtaining PUR, PIR and PUR-PIR foams depends on the isocyanate / polyol ratio.

[0006] PUR, PIR and PUR-PIR foams are well known to those skilled in the art, but foams containing relatively high amounts of fibers, at least locally, do not currently exist, since the addition of fibers entails special technical problems, such as the need to achieve good impregnation of the fibers.

[0007] Indeed, in the specific technical field of using such foams for insulating the body of a tank, said body is exposed at its face exposed to the internal space of the tank to very low temperatures, for example around -160°C for LNG, while the external space of the tank, i.e. conventionally the hull of a ship, is often exposed to much higher environmental temperatures, at least equal to or much higher than the temperature of the surrounding air or sea, which may be around 20°C.

[0008] Thus, the PUR, PIR and PUR-PIR foam blocks used in the insulating bodies of such tanks, when loaded with very cold fluids, called cryogenic fluids, experience very large temperature gradients in their thickness, which leads to the phenomenon of non-uniform shrinkage of the foam blocks. This non-uniform shrinkage of the foam blocks causes a bimetallic effect, where the blocks sag along their longitudinal axis (they have a tendency to lift up significantly at both ends) due to the non-uniform shrinkage of the blocks in the thickness direction. Since the foam blocks are conventionally fixed mechanically or by adhesives, this sagging significantly reduces the available mechanical properties of the PUR, PIR and PUR-PIR foam blocks, and furthermore, locally reduces the thermal properties of the insulating body (which incorporates the foam blocks according to the invention).

[0009] The phenomenon of bimetallic effect and sagging of foam blocks has been compounded in recent years by the fact that the thickness of the foam blocks forming the insulating body for such tanks containing cryogenic liquids has increased, sometimes significantly. In particular, if such tanks consist of a double insulating layer, conventionally called the "primary" and "secondary" layer (this secondary layer being placed furthest from the cryogenic liquid), in modern structures such as the Mark type, the thickness E of the secondary insulating layer has increased significantly. Thus, the thickness E of the secondary insulating layer has changed from 170 mm (millimeters) in the Mark III structure to 300 mm in the Mark III Flex structure and 380 mm in the Mark III Flex+ structure.

[0010] If the thickness of the secondary insulation layer is significantly greater than that of the primary insulation layer, the bimetallic effect and sagging of the secondary insulation layer can have very detrimental structural effects on the insulated body of the sealed insulated tank.

[0011] Constructions such as those described in documents FR 2 882 756, WO 2017 / 202667 and JP 2005225945 are known, but none of them satisfactorily solve the specific technical problem mentioned above.

[0012] At present, there are no polyurethane and polyisocyanurate foam blocks, fiber reinforced or not, that can effectively address this problem, in other words, there are no PUR, PIR and PUR-PIR foam blocks that have thermomechanical stability between their initial state (in a homogeneous thermal environment) and their use state, i.e. when used in a tank containing a cryogenic liquid.

[0013] To overcome the problems of distortion and geometric instability between these two states of the foam blocks, specially shaped blocks are currently manufactured, in particular those incorporating notches or with reduced dimensions. The aim is to limit the thermal deformation of each (small) volume element or (small) foam block to an acceptable range. The manufacture of such small foam blocks requires numerous operations for cutting, positioning and joining them to each other, which is quite costly. Furthermore, the presence of many expansion joints significantly reduces the thermal performance of the tank.

[0014] Also, in a particular embodiment of the insulating body of the tank, the existing foam block is placed in a container, typically a box, made of plywood wood, such as fir, birch, beech, etc. In such an embodiment, the lower and upper faces of the foam block are glued to the inner surface of the container in order to correctly position the block. However, during cooling, i.e. when the tank is in use (it contains a cryogenic liquid), the central or central part of the foam block shrinks significantly, while the upper and lower regions of the block are restrained by being glued to the inner wall of the container. Due to the fact that the thermal contraction coefficient of the foam is much higher than that of the plywood, this phenomenon leads to distortions in the shape of the block in the used / utilized state, such that the side edges of the block assume a substantially arc-like or inverse arc-like shape with a circular arc, resulting in empty spaces between the foam block and the adjacent members, i.e. the side walls of the plywood container. Such empty foam spaces are proportionally damaging to the insulating properties of the insulating body of the tank, and can therefore be the cause of the appearance of the undesirable phenomenon of thermal convection. Summary of the Invention

[0015] The present invention also contemplates providing solutions to such problems that are specific to certain uses of polyurethane (PUR) and / or polyisocyanurate (PIR) foam blocks.

[0016] In this context, the applicant has successfully developed a manufacturing process for polyurethane (PUR) and / or polyisocyanurate (PIR) foams containing a large amount of fibers, which allows the foam to maintain its shape / structural integrity throughout the foam block while having excellent mechanical and thermal properties when the block is in use, i.e. in the thermal environments which differ significantly between the two faces, top and bottom.

[0017] The present invention therefore aims to overcome the drawbacks of the current state by providing a particularly effective solution for industrially obtaining, possibly (very) large, fibre-reinforced PUR / PIR foams whose mechanical / thermal properties are optimal and at least substantially similar between their initial state (at rest, in which the foam block is in a substantially homogeneous thermal environment) and their use / utilisation state, in which the foam block is in a very heterogeneous thermal environment, with a difference of at least 80°C, or even at least 100°C, between its top surface (on the tank's containment side) and its bottom surface (on the outside of the tank), considered along the thickness of the block.

[0018] The applicant, after carrying out various studies and analyses, has discovered a fiber reinforced polyurethane (PUR) and / or polyisocyanurate (PIR) foam block and its preparation, which can solve the technical problems associated with the very large changes in the thermal environment of the PUR / PIR foam block during use.

[0019] Advantageously, according to the preferred embodiments, it is also possible to very significantly reduce the manufacturing costs of such fiber-reinforced foams, by very significantly reducing the loss of material from the foam block, which was previously unavoidable in the prior art when cutting the foam block to obtain the desired (parallelipepiped) dimensions.

[0020] Therefore, the present invention provides a fiber-reinforced polyurethane / polyisocyanurate foam block for the insulating body of a sealed insulating tank, the density of the fiber-reinforced foam block being 30-300 kg / m 3 and the fiber-reinforced polyurethane / polyisocyanurate foam block has an average fiber density T fand a width L of at least 10 centimeters, advantageously between 10 and 500 centimeters, and a thickness E from the lower surface of the block to its upper surface, said thickness E being at least 10 centimeters, advantageously between 10 and 100 centimeters, said fiber reinforced polyurethane / polyisocyanurate foam block being composed of cells for storing a gas, advantageously having a low thermal conductivity.

[0021] The fiber reinforced polyurethane / polyisocyanurate foam block is composed of at least 95% by weight of the block of cells, which advantageously have low thermal conductivity, polyurethane / polyisocyanurate foam, and fibers.

[0022] The foam block according to the invention is (mainly) composed of polyurethane (PUR) and / or polyisocyanurate (PIR) foam, preferably of single nature fibres such as glass fibres, gas trapped in cells and optionally a minimal proportion of fillers and other functional auxiliary substances, i.e. the latter amounting to at most 5% by weight, more preferably at most 2% or 1% by weight, of the foam block according to the invention (fibre reinforced polyurethane / polyisocyanurate foam blocks are composed of gas storing cells, polyurethane / polyisocyanurate foam and fibres to at least 98% or 99% by weight of said block). This is because the foam block according to the invention can be obtained by the following operation: - a single operation of foam preparation preferably in a double band laminator (DBL) (optionally mixing reactive components of fillers / auxiliaries with fibres), - The above operations, conventionally complemented by a cutting operation on the upper surface of the block for adhesive fixing of the peripheral zones, as described below.

[0023] The foam block according to the invention comprises: - said foam block comprises, along its thickness E, two peripheral zones, one called the upper zone and extending from the upper surface of said block, and the other called the lower zone and extending from the lower surface of said block, said two zones each occupying a maximum of 20% along said thickness E of said block and separated by a zone called the intermediate zone; The peripheral zones, which are the upper and lower zones, have a ratio of 2 / 3≦(T f upp. / T f low. )≦3 / 2 fiber density T f upp. and T f low. Each of them presents, the fiber density T of said intermediate zone; f int. is smaller than the density of the peripheral zone, i.e., T f int. <T f upp. , and T f int. <T f low. That is, It is characterized by:

[0024] The present invention applies particularly, but not exclusively, to cases where the foam block is installed in a secondary layer, conventionally designated "secondary." Preferably, in the present application, the foam block exhibits a thickness of at least 25 centimeters (cm), more preferably at least 30-35 cm.

[0025] The terms "top, upper, upper side" and "bottom, lower, lower side" are understood to mean the sense and orientation given to the foam block when placed in place in the insulating body of the tank. Thus, the top or upper surface of the foam block is located near or on the side of the container of the tank when the insulating body is placed in the tank. In contrast, the bottom or lower surface of the foam block is located facing or on the side of the outside of the tank, i.e. in particular facing the hull of the vessel, if the tank is incorporated or installed in a vessel for the transport and / or storage of cryogenic liquids.

[0026] It is therefore understood that in the production or preparation of the foam block the concepts or terms "above, above, upper side" and "below, below, lower side" do not yet have any meaning, since the foam block has not yet been installed in the insulating body of the tank. In other words, it is entirely possible to prepare the foam block according to the invention in such a way that at the exit of its preparation / production line it is obtained in a state opposite to that of its final installation / assembly in the insulating body of the tank.

[0027] The expression "along its thickness E" is understood as meaning the fact that, with regard to the various peripheral, intermediate and also median / central zones described below, these zones represent the volume of the considered fiber-reinforced polyurethane (PUR) and / or polyisocyanurate (PIR) foam block by cutting along a section having a thickness E, as shown in particular in Figures 3 and 4, so as to form, respectively, block portions exhibiting the same width L and the same length (only the thickness differing) as the foam block according to the invention.

[0028] The expression "cells storing gas" is understood to mean the fact that the polyurethane / polyisocyanurate foams present closed cells containing gas, preferably exhibiting low thermal conductivity, originating from the gas injected at the nucleation stage of the reaction mixture or originating directly or indirectly from chemical or physical blowing agents.

[0029] The term "fibers" or the expression "fibrous reinforcement" is understood to refer to the fact that fibers can be provided in two distinct forms: - at least one form of fabric made of fibers, the fibers of which are perfectly aligned along at least one direction, in other words the fibers exhibit at least one preferred fiber direction. The expression "fabric made of fibers" refers to a clear technical definition known per se to the person skilled in the art. - or in the form of at least one mat of fibers in which the fibers do not exhibit any apparent orientation, in other words in which the fibers are essentially oriented isotropically along the surface of the layer of the mat. Likewise, the expression "mat of fibers" refers to a clear technical definition known per se to the person skilled in the art.

[0030] According to one embodiment, the expression "gas having (advantageously) low thermal conductivity" is understood to mean the gas that is generated from the blowing agent. If the blowing agent is said to be "chemical", this is due to the chemical reaction of the blowing agent. If the chemical blowing agent consists of water, then carbon dioxide (CO 2 ). Physical blowing agents include, for example, molecular nitrogen (N 2 ), molecular oxygen (O 2 ), carbon dioxide, hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, and mixtures thereof, as well as the corresponding alkyl ethers. Molecular nitrogen N 2 , molecular oxygen O 2 , or CO 2 Physical blowing agents such as are gaseous. These gases are dispersed or dissolved in a liquid mass of copolymer under high pressure, for example using a static mixer. Reducing pressure in the system produces a cellular structure by bubble nucleation and growth.

[0031] "Average fiber density T f " is understood to mean the fiber density expressed as the weight of fibers relative to the total weight of the fiber-reinforced foam block, without taking into account the variable local proportion (within the block) of these fibers.

[0032] The fibre reinforced foam blocks are therefore suitable not only for tanks integrated into a supporting structure but also as external insulation associated with self-supporting / semi-self-supporting tanks of type A, B or C according to the (IMO) IGC regulations, i.e. self-supporting tanks storing and / or transporting very low temperature liquids such as LNG or LPG.

[0033] Finally, the thermal properties of the fiber-reinforced foam block are at least comparable to those of non-fiber-reinforced foam blocks of the prior art: more precisely, the foam block exhibits a thermal conductivity at thickness E of less than 30 mW / mK (milliwatt per metre per Kelvin), i.e. 0.03 W / mK, preferably less than 25 mW / mK, measured at 20° C., and a thermal conductivity of less than 20 mW / mK at the top surface of the block at −160° C., when the foam block is in a usable state and when the tank in which it is housed contains LNG.

[0034] Other advantageous features of the present invention are briefly presented below.

[0035] Preferably, the two peripheral zones each occupy at most 10% along the thickness E of the block.

[0036] According to a preferred embodiment of the invention, the intermediate zone comprises a central zone surrounded by two median zones, the central zone occupying at most 20% along the thickness E, preferably at most 10% along the thickness E, and the fibre density T f cen. is the fiber density T of the median zone f med. At least 1.5 times greater than T f cen. ≧1.5T f med. It is.

[0037] This embodiment is shown in accompanying Figure 4 and more specifically addresses the problem of shrinkage in the core or central zone of the foam whilst avoiding the bimetal phenomenon due to peripheral zones having a higher fibre density.

[0038] According to another characteristic of this embodiment, the fiber density T f cen. is the fiber density T of the peripheral zones, which are the upper and lower zones. f upp. and T f low. For 0.5≦T f cen. / (T f upp. or T f low.)≦2.

[0039] Preferably, the density of the fiber reinforced foam block is 50 to 250 kg / m 3 , preferably 90 to 210 kg / m 3 For foam blocks used in self-supporting (types B and C) or semi-self-supporting (type A) tanks, the density range of the fiber reinforced foam block is preferably 30-90 kg / m 3 In the case of membranes, the more suitable density range is 90 to 210 kg / m 3 Please note that.

[0040] Advantageously, at least 60%, preferably at least 80%, of the cells, which advantageously store a gas having a low thermal conductivity, exhibit an elongated or elongated shape along an axis parallel to the axis of thickness E of the fiber reinforced polyurethane / polyisocyanurate foam block.

[0041] According to one possibility offered by the invention, the fibres consist of glass fibres or basalt fibres, preferably of glass fibres.

[0042] Preferably, the fibers are long continuous fibers.

[0043] The expression "the fibres are long and continuous" (or "long and continuous fibres") is understood as meaning the fact that all of the fibres, or, where appropriate, the aggregates of a collection of fibres (fibers adhered or fixed to one another), or at least 90% of the fibres by total weight of said fibres, whether alone or in aggregates forming the equivalent of a single fibre, exhibit a length of at least 5 centimetres (cm).

[0044] Preferably, the average fiber density T f is 2% to 25%, preferably 6% to 20%.

[0045] Preferably, the foam block according to the invention is provided in the shape of a parallelepiped or a cube.

[0046] It is clearly understood that this foam block having a parallelepiped or cubic shape may, despite being described as having a parallelepiped or cubic shape, have one or more local convexities, such as continuous anchors, or conversely may have hollow or cavity portions.

[0047] Advantageously, the lower surface and / or the upper surface of the block present anchors engageable with engagement means (not shown in the accompanying drawings) of the insulating body to secure the foam block to the body, preferably the anchors being made of a material different from the foam or the fibres.

[0048] These anchors are advantageously metallic elements presenting, for example, L-shaped mounting lugs or, for example, L-shaped slots / openings etc., for engaging with an element or part of the insulating body surrounding or housing the fibre-reinforced foam block (these anchors can also be made of plastic / polymer or composite material combining one or more polymers with ceramic and / or metallic materials). This part of the insulating body can be made of a metallic membrane for sealing the vessel, for example made of stainless steel or based on manganese, in the case of membrane tanks, or of a vapour barrier (with the technical function of ensuring sealing against the ambient environment outside the tank), in the case of self-supporting or semi-self-supporting tanks of type A, B or C. In one possibility offered by the invention, this element or this part of the insulating body (in membrane tanks) presents a notch or similar, intended to allow engagement with a part of an anchor for mechanically maintaining or holding the fibre-reinforced foam block to the other element of the insulating body. Of course, these anchors may also have the function of fastening the foam block to the ship's hull in the case of membrane tanks, or to a free-standing structure in the case of free-standing tanks of type A, B or C. It is understood that these anchors are present on the underside of the foam block.

[0049] In the context of the present invention, these anchors are inserted into the fiber reinforcement constituting at least partly the lower or upper layer of the fiber reinforced laminate, the anchors being arranged on a surface such that they do not protrude beyond said surface after preparation / finishing of the foam block.

[0050] Advantageously, the fiber-reinforced foam block according to the invention comprises, in a proportion of 0.1% to 5% by weight, an organophosphorus-based flame retardant, advantageously triethyl phosphate (TEP), tris(2-chloroisopropyl)phosphate (TCPP), tris(1,3-dichloroisopropyl)phosphate (TDCP), tris(2-chloroethyl)phosphate or tris(2,3-dibromopropyl)phosphate, or mixtures thereof, or an inorganic flame retardant, advantageously red phosphorus, expandable graphite, aluminium oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulfate or cyanuric acid derivatives, or mixtures thereof.

[0051] The present invention also provides a method for producing a semiconductor device comprising the steps of: a tank integrated into a support structure comprising at least one sealed, insulated tank comprising at least one sealed metal membrane made up of a number of metal sheets or plates, which may be provided with corrugations, and an insulating body comprising at least one insulating barrier adjacent to said membrane, or - Tanks of type A, B or C according to the definition of the IGC Code, equipped with at least one insulated body; The present invention relates to a sealed insulated tank comprising:

[0052] The tank according to the invention is characterized in that said insulating body comprises a plurality of fibre-reinforced polyurethane / polyisocyanurate foam blocks as briefly described above.

[0053] The expression "IGC Code" is understood to mean the "International Code for the Construction and Equipment of Ships for the Carriage of Liquefied Gases in Bulk", which is well known to those skilled in the art, such as the aforementioned types B and C tanks.

[0054] It should be noted that, in particular in the IGC Code, the use of the expression "membrane tank" instead of "integral tank" can mean the same category of tanks specifically equipped on tankers transporting and / or storing at least partly liquefied gas. "Membrane tanks" are built into a supporting structure, whereas tanks of types A, B or C are called self-supporting or semi-self-supporting (especially type A).

[0055] Finally, the invention also relates to a ship for transporting cryogenic liquid products, comprising at least one hull and one sealed, insulated tank as briefly described above, said tank being arranged in said hull or installed on board said ship, if said tank is a type A, B or C tank as defined by the IGC Code.

[0056] Advantageously, such a vessel comprises at least one sealed, insulated tank as described above, when the tank consists of a tank integrated in a support structure (membrane tank). Said tank comprises two successive sealed barriers: one a primary barrier in contact with the product contained in the tank, and the other a secondary barrier, placed between the primary barrier and the support structure and preferably formed from part of the vessel wall. These two sealed barriers are interleaved with two insulating barriers, or alternatively a single insulating barrier is placed between the primary barrier and the support structure.

[0057] Such tanks are conventionally designated according to the International Maritime Organization (IMO) codes as integral tanks, for example tanks of type NO 96®, NO 96L03®, NO 96L03+ or NO 96, or tanks of type NO, including Mark III®, Mark III® Flex or Flex+, preferably tanks of type NO.

[0058] Preferably, the tanks, also referred to as membrane type or types A, B or C, contain liquefied natural gas (LNG) or liquefied gas (LG).

[0059] The present invention also relates to a transfer system for cryogenic liquid products comprising a vessel as described above, a thermally insulated pipe arranged to connect the tank installed in the hull of the vessel to a floating or land-based storage unit, and a pump for driving a flow of cryogenic liquid product from the floating or land-based storage unit to the vessel or from the vessel to the floating or land-based storage unit via the thermally insulated pipe.

[0060] The present invention also relates to a process for offloading a vessel as described above, in which cryogenic liquid product is transported from said floating or land-based storage unit to said vessel or from said vessel to said floating or land-based storage unit via a thermally insulated pipe.

[0061] The present invention also relates to a process for the preparation of the fiber-reinforced polyurethane / polyisocyanurate foam block of the insulating body of a closed, insulated tank, as briefly described above, comprising: a) mixing the chemical components necessary to obtain a polyurethane / polyisocyanurate foam, said components including reactants for obtaining the polyurethane / polyisocyanurate, optionally at least one reaction catalyst, optionally at least one emulsifier, and at least one blowing agent; b) impregnating a plurality of fiber reinforcements by gravity flow of the mixture of chemical components, the fiber reinforcements being arranged in overlapping layers and exhibiting variable fiber density, the fiber reinforcements extending essentially along a direction perpendicular to the direction of gravity flow; c) forming and expanding the fiber reinforced polyurethane / polyisocyanurate foam, the expansion of the fiber reinforced polyurethane / polyisocyanurate foam is by free expansion, i.e. not restricted by the volume of a closed section of at least one side, preferably the top side, or the expansion of the fiber reinforced polyurethane / polyisocyanurate foam is physically constrained by the walls of a double belt laminator, preferably a tunnel of rectangular cross section with a distance between the laterally disposed walls equal to L and a distance between the horizontally disposed walls equal to E, which tunnel surrounds the expanding fiber reinforced foam to obtain the fiber reinforced polyurethane / polyisocyanurate foam block; The present invention relates to a process for preparing a fiber-reinforced polyurethane / polyisocyanurate foam block, comprising:

[0062] The expression "cream time" is understood to mean the time, measured from the mixing of the chemical components, that is required for the chemical components to start the polymerization reaction and, as a result, for the mixture of components to start the expansion and crosslinking step c) (= formation of a fiber-reinforced PUR / PIR foam). This cream time is information well known to those skilled in the art. In other words, the cream time is the time that elapses after mixing the chemical components at room temperature until the mixture turns white, due to the effect of the nucleation of bubbles (cells that store gas) and the expansion of the foam. The cream time is measured visually or using an ultrasonic sensor to detect the change in thickness that reflects the formation of a foam.

[0063] The expression "the fiber reinforcements extend essentially along a direction perpendicular to the direction of the flow of the mixture of chemical components due to gravity" is understood as meaning the fact that these fiber reinforcements are provided in the impregnation step b) in the form of layers of small thickness extending along a plane perpendicular to the flow direction of the mixture of said components. Thus, as shown in FIG. 1, a number of fiber reinforcements exhibiting a width L and arranged in superposed layers are pulled in a longitudinal direction I while the mixture of chemical components is deposited on the fiber reinforcements from a distributor that allows / enables the flow of the mixture of chemical components due to gravity. In other words, the mixture of chemical components selectively flows out of the distributor under pressure and falls at least under the effect of its own weight onto the stacked fiber layers, thereby impregnating these fiber reinforcements from the upper layer to the lower layer.

[0064] According to one embodiment of the present invention, when step c) is performed by free expansion, at least immediately after the cutting of the free expansion face is performed, at least one of the peripheral zones, preferably the upper zone, is formed and fixed independently so as to form the foam block.

[0065] In the compositions according to the invention, the use of chemical blowing agents can be combined with the use of physical blowing agents, which are preferably mixed with the foamable (co)polymer composition in the liquid or supercritical state and then converted to the gas phase during the expansion process of the PUR / PIR foam.

[0066] Chemical and physical blowing agents are well known to those skilled in the art, and all will be selected by the skilled artisan in appropriate amounts depending on the PUR / PIR foam to be obtained.

[0067] The term polyol is understood to mean any carbon-based structure having at least two OH groups.

[0068] Depending on the isocyanate / polyol ratio, PUR, PIR and PUR-PIR foams are obtained, and therefore depending on this ratio, PUR, PIR or PUR-PIR foams are obtained. When the ratio is from 1:1 to 1:1.3, a polyurethane (PUR) foam is obtained; - 1:1.3 to 1:1.8, polyurethane-polyisocyanurate PUR-PIR foams are obtained; When it is between 1:1.8 and 1:2.8, a polyisocyanurate PIR foam will be obtained.

[0069] Polyisocyanates suitable for forming PUR, PIR and PUR-PIR foams are known to those skilled in the art and include, for example, aromatic, aliphatic, cycloaliphatic and arylaliphatic polyisocyanates and mixtures thereof, preferably aromatic polyisocyanates.

[0070] Examples of polyisocyanates suitable within the scope of the present invention include the 4,4'-, 2,4'- and 2,2'-isomers of diphenylmethane diisocyanate (MDI), compounds resulting from the polymerization of these isomers, aromatic isocyanates such as toluene 2,4- and 2,6-diisocyanate (TDI), m- and p-phenylene diisocyanate, naphthalene 1,5-diisocyanate, and the like. Aliphatic, cycloaliphatic or arylaliphatic isocyanates can be used, such as 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate (CHDI), bis(isocyanatomethyl)cyclohexane (H6XDI, DDI), tetramethylxylylene diisocyanate (TMXDI), etc. It is also possible to use any mixture of these diisocyanates. Advantageously, the polyisocyanate is the 4,4'-, 2,4'- and 2,2'-isomer of diphenylmethane diisocyanate (MDI).

[0071] In general, when forming PUR, PIR or PUR-PIR foams, it is known to add a reaction catalyst selected from a tertiary amine such as N,N-dimethylcyclohexylamine or N,N-dimethylbenzylamine, or an organometallic compound such as bismuth, potassium or tin to a mixture of polyol, polyisocyanate and blowing agent.

[0072] According to a preferred embodiment of the present invention, advantageously, the positioning of the tunnel walls of the double belt laminator (DBL) is defined such that the constraint on the expansion of the fiber reinforced polyurethane / polyisocyanurate foam results in a volume of the fiber reinforced polyurethane / polyisocyanurate foam at the outlet of the double belt laminator that is 85% to 99%, preferably 90% to 99%, of the expansion volume of the same fiber reinforced polyurethane / polyisocyanurate foam in the case of free expansion without the constraint of the walls of such double belt laminator. In this case, a foam is obtained in which the egg-shaped cells are preferably oriented along the axis E. This results in the above-mentioned properties in the plane perpendicular to the axis E, as well as the advantageous property of crush resistance along the axis E (measured according to the ISO 844 standard). Tests and experiments have been carried out by the applicant to determine the above-mentioned broad and preferred ranges, but for the sake of clarity and brevity, they will not be presented here.

[0073] The above-mentioned specific parameter constraints on the expansion of the fiber-reinforced PUR / PIR foam in the DBL result in a fiber-reinforced PUR / PIR foam block in which at least 60%, and usually more than 80% and even more than 90% of the cells storing the gas with low thermal conductivity extend longitudinally along an axis parallel to the axis of the thickness E of the foam block, while a contribution to the perfect homogeneity of the fiber-reinforced foam block is obtained in addition to the specific selection related to the properties of the fiber reinforcement and the viscosity of the mixture of the chemical components, the orientation of the cells and the fiber content T in the block. f These two properties, that is, homogeneity along different peripheral or central zones, allow to obtain a fiber-reinforced foam block exhibiting excellent mechanical properties along the thickness E (compressive strength) and in the plane perpendicular to the thickness direction (tensile strength and low thermal shrinkage coefficient).

[0074] An elongated or stretched shape may be defined by a shape that has an extended length, i.e., it has one dimension, the length, that is greater than the other dimensions (width and thickness).

[0075] According to another embodiment provided by the present invention, the expansion of the fiber reinforced polyurethane / polyisocyanurate foam is free, i.e., not constrained by the volume of a closed section.

[0076] In this example, unlike the embodiment of the preparation according to the invention using a DBL, the preparation of the fiber reinforced polyurethane / polyisocyanurate foam is said to be by "free rise" insofar as the expansion of the fiber reinforced foam is free on at least one side or surface of the expansion, since unlike a mold that defines a finite volume, the expansion of the fiber reinforced foam is not restricted on this side or surface. Conventionally, free rise is achieved by omitting the "top" cover, where the side walls prevent the foam from spilling over the sides. The foam naturally rises upwards, possibly beyond the top of the side walls.

[0077] Advantageously, following the step of free expansion of the fibre reinforced polyurethane / polyisocyanurate foam, said fibre reinforced foam is cut so as to obtain fibre reinforced polyurethane / polyisocyanurate foam blocks as defined above.

[0078] According to one possibility offered by the invention, not shown in the attached drawings, immediately after the step of impregnating the fiber reinforcement, the mixture of components and at least the foaming agent impregnating the fibers is subjected to a pressure application system (which may for example be a roller system of the type called "nip rolls") intended to apply pressure to the upper surface of the assembly of said mixture and fibers. This pressure system allows the planning of the upper surface of this assembly, while the pressure exerted on it contributes to accelerating the impregnation of the fibers in said mixture. This pressure system may consist of a single or double roller. Their relative position above the liquid assembly and possibly below the foam support is adjusted so that the liquid assembly is forced to spread completely and uniformly. In this way, therefore, an equal amount of liquid assembly is obtained at any position of the section defined by the distance between the two rollers or the upper roller and the conveyor belt. In other words, the main purpose of this pressure system is to complement the liquid distributor by contributing to make the liquid assembly uniform in thickness / width before its expansion in the main part.

[0079] Preferably, the dynamic viscosity η of the component mixture is between 30 mPa.s and 3000 mPa.s (i.e., between 0.03 Pa.s and 3 Pa.s), preferably between 50 mPa.s and 1500 mPa.s (i.e., between 0.05 Pa.s and 1.5 Pa.s) at atmospheric temperature (25°C) and atmospheric pressure (1015 mPa).

[0080] The dynamic viscosity of the component mixture can be measured, for example, using a Brookfield type viscometer or, for example, a rheometer according to ISO 2555 standard.

[0081] In general, it is expressly understood that the subject of the present invention uses materials / products available on the market, the properties of which, in particular those relating to density and (dynamic) viscosity, are taken from the specifications relating to the material / product in question.

[0082] Advantageously, at least 60% of said cells, which advantageously store a gas having a low thermal conductivity, present an elongated or elongated shape along an axis parallel to the axis of thickness E of the fiber reinforced polyurethane / polyisocyanurate foam block.

[0083] More preferably, at least 80%, preferably at least 90%, of said cells, which advantageously store a gas having a low thermal conductivity, exhibit an elongated or elongated shape along an axis parallel to the axis of thickness E of the fiber reinforced polyurethane / polyisocyanurate foam block.

[0084] It is clearly understood that the properties relating to the elongated shape of the cells for storing a gas having advantageously low thermal conductivity and their content / proportion in the block according to the invention are more particularly intended for the context of carrying out the preparation process with DBL, but are in no way limited to this scenario, since such a preferred orientation of the cells for storing a gas having advantageously low thermal conductivity is obtained in the case of free expansion, more specifically in the absence of an upper wall / cover limiting the expansion of the fiber-reinforced foam.

[0085] Preferably, the fibers (fiber reinforcement) are arranged over the entire width L, and the impregnation step b) of the fibers with the mixture of components and blowing agent to obtain a fiber-reinforced polyurethane / polyisocyanurate foam is carried out simultaneously over the entire width L via a controlled liquid distributor.

[0086] The term "simultaneously" is understood to mean the fact that the liquid mixture (of reactants and at least blowing agent) reaches the fibers over a section of width L at the same time along this section, so that the impregnation of the different fiber reinforcements starts or is carried out at the same time or at the same rate for sections of the same width along the thickness (or height) of the foam block.

[0087] Advantageously, the blowing agent consists of a physical and / or chemical blowing agent, preferably a combination of the two types.

[0088] Preferably, the physical blowing agent is selected from alkanes and cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals, fluoroalkanes having 1 to 8 carbon atoms, fluoroolefins, and tetraalkylsilanes having 1 to 3 carbon atoms in the alkyl chain, in particular tetramethylsilane, or mixtures thereof.

[0089] Examples of compounds under this premise may be propane, n-butane, isobutane, cyclobutane, n-pentane, isopentane, cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, and fluoroalkanes. The fluoroalkanes are selected so that they do not destroy the ozone layer, for example trifluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane, and heptafluoropropane. Examples of fluoroolefins include 1-chloro-3,3,3-trifluoropropene and 1,1,1,4,4,4-hexafluorobutene (e.g., HFO FEA1100 sold by DuPont).

[0090] According to a preferred embodiment of the invention, the physical blowing agent selected is 1,1,1,3,3-pentafluoropropane or HFC-245fa (sold by Honeywell), 1,1,1,3,3-pentafluorobutane or 365mfc (e.g. Solkane® 365mfc sold by Solvay), 2,3,3,3-tetrafluoroprop-1-ene, 1,1,1,2,3,3,3-heptafluoropropane (also known internationally as HFC-227ea, sold by DuPont for example), 1,1,1,4,4,4-hexafluorobutene (e.g. HFO FEA1100 sold by DuPont), trans-1-chloro-3,3,3-trifluoropropene (Solstice LBA - Honeywell), or mixtures thereof.

[0091] Advantageously, the chemical blowing agent consists of water.

[0092] Advantageously, in step a) of mixing the chemical components, a nucleation gas is introduced into at least one polyol compound, preferably under a pressure of 20 to 250 bar, using a static / dynamic mixer, the nucleation gas making up 0 to 50% by volume of the polyol, preferably 0.05 to 20% by volume of the polyol.

[0093] Preferably, in step a) of mixing the chemical components, the temperature of each reactant to obtain the polyurethane / polyisocyanurate is between 10°C and 40°C, preferably between 15°C and 30°C.

[0094] Preferably, according to a preferred embodiment of the present invention, the final mixing of the polyol, isocyanate and / or blowing agent streams is carried out in a low pressure (<20 bar) or high pressure (>50 bar) mixhead using dynamic or static mixers.

[0095] According to one possibility offered by the invention, in step a) an organophosphorus flame retardant is further added to the mixture, advantageously triethyl phosphate (TEP), tris(2-chloroisopropyl)phosphate (TCPP), tris(1,3-dichloroisopropyl)phosphate (TDCP), tris(2-chloroethyl)phosphate or tris(2,3-dibromopropyl)phosphate, or mixtures thereof, or alternatively an inorganic flame retardant, in particular red phosphorus, expandable graphite, aluminium oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulfate, cyanuric acid derivatives, or mixtures thereof.

[0096] Also, diethylethanephosphonate (DEEP), triethylphosphonate (TEP), dimethylpropylphosphonate (DMPP), and diphenylcresylphosphonate (DPC) can be used as flame retardants.

[0097] This flame retardant, when present in the composition according to the invention, is found in an amount of 0.01% to 25% by weight of the PUR / PIR foam.

[0098] The following description is given by way of example only and without limitation with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0099] [Figure 1] FIG. 1 is a schematic diagram showing the various steps of the process for preparing a fiber reinforced PUR / PIR foam block according to the present invention. [Diagram 2] FIG. 2 is a schematic diagram of one embodiment of a controlled liquid distributor according to the present invention. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a foam block according to one embodiment of the present invention illustrating the peripheral zone as well as the intermediate zone. [Figure 4] FIG. 4 is a schematic cross-sectional view of a foam block according to another embodiment of the present invention showing a peripheral zone as well as an intermediate zone, the intermediate zone exhibiting two median zones sandwiching a central zone. [Diagram 5] FIG. 5 is a schematic diagram of two sets of insulation panels fixed together forming the primary and secondary insulation spaces, respectively, for a tank, the insulation panels being made from a plurality of fiber reinforced polyurethane / polyisocyanurate foam blocks according to the invention. [Figure 6] FIG. 6 is a partial view of a foam block according to the present invention, in which a number of anchors are arranged to allow fixing or fastening of the foam block during its preparation. [Figure 7] FIG. 7 shows a schematic cross-sectional view of an embodiment of an anchor that can be inserted into a foam block according to the invention. [Figure 8] FIG. 8 is a schematic cutaway view of an LNG tanker tank and a loading / unloading terminal for said tank, in which two sets of insulation panels of the type shown in FIG. 7 are installed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0100] The preparation of the fiber-reinforced PUR / PIR foam block 20 according to the invention is preferably carried out in the presence of a catalyst capable of accelerating the isocyanate / polyol reaction. Such compounds are described, for example, in the prior art document entitled "Kunststoffhandbuch, Volume 7, Polyurethane" published by Carl Hanser AG, 3rd Edition, 1993, Chapter 3.4.1. These compounds consist of amine-based catalysts and catalysts based on organic compounds.

[0101] Preferably, the preparation of the fiber reinforced PUR / PIR foam block 20 according to the present invention is carried out in the presence of one or more stabilizers intended to promote the formation of a regular cell structure during the formation of the foam. These compounds are well known to those skilled in the art and include, for example, foam stabilizers composed of silicones, such as siloxane-oxyalkylene copolymers, and other organopolysiloxanes.

[0102] Those skilled in the art are aware of amounts of stabilizer ranging from 0.5% to 4% by weight of the PUR / PIR foam, depending on the reactants envisaged.

[0103] According to one possibility offered by the invention, in step a) of the preparation process, the mixture of chemical components may comprise plasticizers such as polybasic esters, preferably dibasic esters, carboxylic acids with monohydric alcohols or may consist of polymeric plasticizers such as polyesters of adipic, sebacic and / or phthalic acid. The skilled person knows that, depending on the reactants used, amounts of plasticizer between 0.05% and 7.5% by weight of the polyurethane / polyisocyanurate foam are conventionally envisaged.

[0104] It is contemplated that the organic and / or inorganic fillers, particularly reinforcing fillers, may be mixtures of chemical components such as siliceous minerals, metal oxides (e.g., kaolin, titanium or iron oxides) and / or metal salts, etc. When such fillers are present in the mixture, the amount is conventionally between 0.5% and 15% by weight of the PUR / PIR foam.

[0105] It should be noted that the present invention is not intended to add technical teachings on the formation of PUR / PIR foams, both in terms of the nature of the essential chemical components and in terms of optional functional agents and their respective amounts. The skilled person knows how to obtain different types of fiber reinforced PUR / PIR foams, and the preparation of the present invention is described starting from the specific selection of the properties of the fiber reinforcements, in particular the fiber density in the different fiber reinforcements, and the specific selection of the foam for the impregnation of said reinforcements.

[0106] Therefore, what the present invention is primarily directed to herein is not a new chemical preparation of fiber reinforced PUR / PIR foam, but rather a new fiber reinforced PUR / PIR foam block 20 with a very specific fiber density distribution along the thickness or height of the block 20, which, apart from a slight shrinkage in dimensions along all its directions with a constant factor, does not sag and deform in its overall parallelepiped shape / structure, and preferably does not shrink in the center of the foam block 20, which tends to result in the phenomenon of thermal convection.

[0107] Thus, as shown in Figure 1, a number of fiber reinforcements 10 are unwound and placed along a parallel arrangement on a conveyor belt 11 intended to transport these reinforcements 10 and the components forming the PUR / PIR foam, since the impregnation of the fiber reinforcements 10 is carried out by gravity in the context of the preferred method for preparing a fiber reinforced foam block 20 of the invention: a mixture 12 of chemical components, blowing agents and any other functional agents used to obtain the PUR / PIR foam is discharged directly onto the fiber reinforcements 10 from a liquid distributor placed above them.

[0108] Thus, the mixture 12 is applied to all layers of the fiber reinforcement 10, whether these are multiple mats or multiple fabrics of the reinforcement, in a very homogeneous manner for a cream time t, so that the start of expansion of the PUR / PIR foam occurs after all the fiber reinforcement 10 is completely saturated with the mixture 12, or at the earliest at that moment. c In this way, the desired gradient in fiber density can be achieved by expanding the PUR / PIR foam while maintaining a perfect specific distribution of the fibers 10 in the volume of the PUR / PIR foam block 20.

[0109] The object of the invention is achieved by arranging the fiber reinforcements parallel to one another, i.e. in overlapping layers, each of which has a higher or lower fiber density compared to the others. Thus, the fiber reinforcements intended for the peripheral zones 21, 22 and also for the central zone 26, in the embodiment in which the central zone 26 is present, exhibit a higher fiber density than those of the intermediate zones 23 and even of the median zones 24, 25.

[0110] More precisely, the peripheral zones 21, 22 and optionally the central zone 26 exhibit fiber densities within a similar range or area, i.e. have a higher fiber density, and the ratio of the fiber densities of these zones 21, 22, 26 can therefore be defined as being contained in the following inequality: 2 / 3≦T f upp. / T f low .≦3 / 2 and T f int. <T f upp ,T f low .:For the two peripheral zones 21, 22 and the intermediate zone 23 shown in Figure 3. 2 / 3≦T f cen / (T f low. or T f upp .)≦3 / 2 and T f med. <T f low. ,T f upp. ,T f cen.:In the case of the two peripheral zones 21, 22 shown in Figure 4, and the intermediate zone 23 formed by the central zone 26 and the two median zones 24, 25.

[0111] These zones 21, 22, 26 with high fiber density exhibit a fiber density of 10% to 45% by weight of fibers, preferably 12% to 25% by weight of fibers, relative to the local weight of the foam block 20 (assumed in said zone 21, 22 or 26).

[0112] In contrast, the intermediate zone 23 (when the central zone 26 is not present) and the median zones 24, 25 (when the central zone 26 is present) exhibit a relatively low fiber density. In these zones 23 or 24, 25, the fiber density is between 1% and 20% by weight of fibers relative to the local weight of the foam block 20, preferably between 4% and 11% by weight of fibers relative to the local weight of the foam block 20.

[0113] When comparing zones 21, 22, 26 having a high fiber density with zones 23 or 24, 25 having a low fiber density, zones 21, 22, 26 having a high fiber density preferably exhibit a fiber density that is at least greater than the fiber density of zones 23 or 24, 25 having a low fiber density, and more preferably exhibit a fiber density that is 2 to 3 times greater than the fiber density of zones 23 or 24, 25 having a low fiber density.

[0114] In the context of the present invention, the cream time of the components of the mixture 12 for forming the PUR / PIR foam is known to the person skilled in the art and is selected such that the conveyor belt 11 conveys the mass formed from the mixture 12 of the components, the blowing agent and the fibers 10 immediately after the expansion of the foam starts, for example to a double belt laminator, not shown in the attached drawing, in other words the expansion of the PUR / PIR foam is then finished in the double belt laminator.

[0115] In such an embodiment using a double belt laminator (DBL), a pressure system using one or two rollers is selectively placed before the double belt laminator, i.e. between the area of ​​impregnation of the mixture into the fibers and the double belt laminator. When using a DBL, the expansion of the foam volume is carried out in the laminator when the expansion volume of this foam reaches 30% to 60% of the expansion volume of this same foam when the expansion is free, i.e. without any constraints. In this way, the double belt laminator can suppress the expansion of the PUR / PIR foam in its second expansion phase when it has almost reached, or relatively almost reached, its maximum expansion, in other words when the expansion brings the foam into close proximity to all the walls forming the rectangular or square cross-section tunnel of the double belt laminator. According to another way of presenting a particular option of the preparation according to the invention, the gel point of the mixture of components, i.e. the moment when at least 60% of the polymerization of the mixture of components is reached, in other words the moment when 70% to 80% of the maximum volume expansion of the mixture is reached, necessarily occurs in the double belt laminator, possibly in the latter part of the length of the double belt laminator (i.e. closer to the outlet than to the inlet of the laminator).

[0116] As regards the function of the simultaneous discharge of the mixture 12 of chemical components and blowing agent over the entire width L of the fiber reinforcement 10, it is provided by a controlled distributor 15 shown in FIG. 2. Such distributor 15 comprises a feed channel 16 for the mass formed of the mixture 12 of chemical components and at least the blowing agent from a vessel forming a reactant mixer, not shown in the attached drawings, in which, on the one hand, all the chemical components and the blowing agent are mixed, and on the other hand, the nucleation of such mixture and also the heating are carried out. The liquid mass formed of the mixture 12 of chemical components and the blowing agent is then distributed under pressure to the ends of two transversely extending channels 17 in two identical distribution plates 18 extending along the width L, each of which presents a length substantially equal to L / 2, and which are equipped with a number of nozzles 19 for passing said mixture 12 over the fiber reinforcement 10. These passing nozzles 19 consist of orifices with a calibrated cross section presenting a predetermined length. The length of these nozzles 19 is therefore predetermined so that the liquid flows out at the same rate between all the nozzles 19. The aim is to ensure that the impregnation of the fibre reinforcement 10 occurs at the same time, i.e. simultaneously, over the section of width L of the fibre reinforcement 10 and that the surface density of the liquid deposited perpendicularly at each nozzle is equal. In this way, when considering a section of width L of the fibre 10, the impregnation of the layer of fibre 10 with the mixture 12 is carried out in the same manner at all points of said section, since the fibres are impregnated at the same time. This contributes to obtaining, at the outlet of the double belt laminator, a block 20 of fibre reinforced foam whose local density of fibres corresponds exactly to the density of the fibres of each superposed layer of the fibre reinforcement at the moment of the flow due to gravity of the mixture 12.

[0117] The controlled liquid distributor 15 shown in figure 2 is an exemplary embodiment in which two identical distribution plates 18 are used, although other designs can be envisaged as long as the function of distributing the liquid simultaneously over the width sections of the fibres 10 is obtained. Naturally, the main technical feature exploited in this example is the different lengths of the flow nozzles 19, which can be longer or shorter depending on the route or course of the liquid mixture 12 from the supply duct 16 of the distributor 15 to the flow nozzles 19 envisaged.

[0118] PUR / PIR foam cream time T c One of the key points to achieve good impregnation of the fiber reinforcement 10 at the last moment is the selection of a specific viscosity of the liquid (consisting of the mixture 12 of chemical components and blowing agent) which is related to the specific properties of the various fiber reinforcements and can vary depending on the fiber density. The selected viscosity range as well as the permeability properties of the fiber reinforcement must allow good penetration into the first layer of fibers 10 and reach the subsequent layers up to the last layer (the layer below the fibers 10, i.e. the layer located at the bottom in the stack of fiber reinforcements). This allows the impregnation time t i But cream time c The viscosity of the mixture of ingredients 12 is selected, for example by heating, addition of plasticizers, and / or more or less nucleation, such that impregnation of all fibers 10 over a section of width L with the mixture of chemical ingredients and blowing agent 12 is obtained just before the cream time, in other words before or just before the onset of expansion of the PUR / PIR foam.

[0119] The fiber reinforced foam block 20 is intended to be used in a very specific environment, so that specific mechanical and thermal properties must be guaranteed. The fiber reinforced foam block 20 obtained by the preparation according to the invention conventionally forms part of an insulating body 30, i.e. in the example used in FIG. 5, the upper or primary panel 31 and / or the lower or secondary panel 32 of said insulating body 30 of a tank 71 intended to receive a cryogenic liquid such as LNG or LPG. Such a tank 71 may be equipped, for example, on land tanks, floating barges, etc. (for example FSRU "Floating Storage Regasification Unit" or FLNG "Floating Liquefied Natural Gas") or on ships such as LNG tankers transporting this energetic liquid between two ports.

[0120] The foam block according to the invention shown in Figure 6 comprises a number of anchors 40 distributed on its various faces, namely its top face 41 and its side faces 42, 43. These anchors 40 are arranged flush with the surfaces of said faces 41, 42, 43 of the foam block and do not present their thickness (or a thickness that is not large) covering the foam and / or protecting it from the outside.

[0121] FIG. 7 shows such an anchor 40 in cross section. This anchor 40 presents a plate 44 extending along a plane. This plate 44 is provided with a number of orifices 45, which consist of mechanical anchoring means, in other words one of two elements that make it possible to fix the foam block to the insulating body of the tank when they engage with an element of the insulating body (not shown in the accompanying drawings). The plate 44 also comprises a number of identical fixing studs 46 as well as a central fixing stud 47 presenting dimensions greater than those of the fixing studs 46. The function of these studs 46, 47 is to fix the anchor 40 as well as possible to the fibre-reinforced foam block according to the invention. The fixing studs 46 are ideally arranged circumferentially so as to form a circle around the outer periphery or periphery of the anchor 40.

[0122] The anchor 40 shown in FIG. 7 is advantageously placed on the conveyor belt 11 , then the studs 46 , 47 are directed upwards and the plate 44 rests on said belt 11 .

[0123] However, it may also be envisaged to place these anchors 40 on the upper face 41 of the block, or even on the side faces 42, 43, as on the block shown in Figure 6. In the latter case, it may advantageously be envisaged to at least slightly embed the studs 46, 47 in the adjacent / continuous fibre mat prior to its impregnation with the polymer foam.

[0124] Of course, one of the orifices 45 of the anchor 40 can be used as is to form the female part of the anchor, but anchors requiring the use of multiple orifices 45 can also be envisaged. Moreover, these orifices 45 comprise the anchor solution, but the invention is in no way limited to this embodiment, and single or multiple anchors 40 with different shapes and different mechanical properties can be envisaged.

[0125] Referring to Figure 8, a cut-away view of an LNG tanker shows a sealed, insulated tank 71 having a generally prismatic shape mounted on a double hull 72 of the vessel. The wall of the tank 71 comprises a primary containment barrier intended to be in contact with the LNG contained in the tank, a secondary containment barrier arranged between the primary containment barrier and the double hull 72 of the vessel, and two insulating barriers arranged respectively between the primary containment barrier and the secondary containment barrier and between the secondary containment barrier and the double hull 72.

[0126] In a known manner, offloading pipes 73 located on the upper deck of the vessel may be connected by suitable connectors to a shipping or land terminal for transferring a cargo of LNG to or from the tanks 71 .

[0127] FIG. 8 shows an example of a shipping terminal with an unloading station 75, an underwater pipeline 76 and an onshore facility 77. The unloading station 75 is a fixed offshore facility with a movable arm 74 and a tower 78 supporting the movable arm 74. The movable arm 74 supports a bundle of insulated flexible hoses 79 that can be connected to an unloading pipe 73. The pivoting movable arm 74 fits all sizes of LNG tankers. A connecting pipeline (not shown) runs inside the tower 78. The unloading station 75 allows the LNG tanker 70 to load and unload from the onshore facility 77. The facility comprises a liquefied gas storage tank 80 and a connecting pipeline 81 connected to the unloading station 75 via an underwater pipeline 76. The underwater pipeline 76 allows the liquefied gas to be transported over long distances, for example up to 5 km, between the unloading station 75 and the onshore facility 77. This allows the LNG tanker 70 to be kept a greater distance from shore during loading and unloading operations.

[0128] To generate the pressure required for the transfer of the liquefied gas, pumps on board the vessel 70 and / or pumps provided at the onshore facility 77 and / or pumps provided at the loading / unloading station 75 are used.

[0129] As mentioned above, the subject matter of the present invention, i.e. the use or utilization of the fiber reinforced polyurethane / polyisocyanurate foam block, is not intended to be limited to integral tanks in a support structure, but is provided for tanks of types A, B and C of the IGC Code in force at the time of filing this patent application, as well as future versions of this Code, provided that no significant changes are applied to tanks of types A, B and C. Moreover, it is understood that, subject to changes in the IGC Code, other types of tanks may be contemplated applications for the fiber reinforced PUR / PIR foam block 20 according to the present invention.

[0130] The following presents some of the experiments and tests conducted by the applicant to evaluate the subject matter and scope of the present invention, however, it is anticipated that other tests / experiments may have been conducted and will be provided later as needed / requested.

[0131] To demonstrate the invention, polyisocyanurate foam compositions incorporating mat-like fibers are used. These fibers are always provided as long, continuous fibers. More precisely, the length of these fibers is exactly the same in the compositions according to the invention and in the compositions according to the prior art. The applicant has in particular tested the subject matter of the invention having fibers that are said to be short (as opposed to the long, continuous fibers defined above) or provided in the form of a fabric. The results obtained are comparable or substantially similar to those obtained using a mat made of long, continuous fibers, as shown below.

[0132] Thus, other parameters of the preparation of the PIR foam blocks are not allowed to be modified or different between the preparation according to the invention and the preparation according to the prior art, so as to very much ensure only the combination of the fiber density of the fiber reinforcement and the selection of a PIR foam exhibiting a very special creaminess, or one suitable for the particularity of said fiber reinforcement.As a non-exclusive example, mention may be made of the fact that, where appropriate, the nucleation, the amount of blowing agent, the reaction temperature, the nature and amount of the mixture of chemical components, the discharge process, the distance between the injection point of the mixture of chemical components and the DBL or the device allowing free expansion are strictly identical in the case according to the invention and in the case according to the prior art.

[0133] Of course, for clarity and completeness, the examples will illustrate the invention using PUR foam, however, equivalent or substantially similar results have been obtained with PIR foam and PUR / PIR blends.

[0134] Similarly, while free rise techniques were utilized in the preparation of the fiber reinforced foams for which results are presented below, in view of fiber reinforced foams according to the present invention and fiber reinforced foams according to the prior art, Applicants have demonstrated that equivalent or substantially similar results were obtained using DBL.

[0135] It is further understood that all compositions tested in succession are studied under the same density conditions, the parameter of density being involved in the evaluation of performance qualities in compressive strength.

[0136] For the prior art composition, the properties of the fiber reinforcement and PUR foam are as follows:

[0137] [Table 1] JPEG0007607578000002.jpg210170

[0138] For the prior art composition, the properties of the fiber reinforcement and PUR foam are as follows:

[0139] [Table 2] JPEG0007607578000004.jpg249170

[0140] It should be noted that the cream time of the PUR foam used above is logically identical for the compositions according to the prior art and the compositions according to the invention, since the foam used is the same in each case considered.

[0141] After conducting the tests, some results are presented below in a simplified form to illustrate the applicant's findings when the fiber reinforcement is provided in the form of at least one mat of glass fibers.

[0142] [Table 3] JPEG0007607578000006.jpg178170 It should be noted that the first composition in table 3 above (with 8 layers of U809 or U801 for a block with a thickness of 180 mm) consists of a composition according to document FR 2 882 756. The results for such a composition according to document FR 2 882 756 are very significantly inferior to the results obtained with the composition according to the invention (final composition of table 3).

[0143] As can be seen from the results shown in the above table, the fiber-reinforced foams according to the present invention show significantly better results than the fiber-reinforced foams according to the prior art with respect to the three criteria considered in comparing the obtained fiber-reinforced foams.

[0144] Furthermore, it should be noted that the fiber reinforced PUR / PIR foams according to the invention do not exhibit any significant decrease in properties with respect to the (very low) thermal conductivity.

[0145] [Table 4]

[0146] Although the present invention has been described in relation to several specific embodiments, it is by no means limited thereto, but it is extremely clear that the present invention includes all technical equivalents of the described means, and combinations thereof, if they fall within the scope of the present invention.

[0147] Use of the verb "comprise" or "include" and its conjugations does not exclude the presence of elements or other steps other than those stated in a claim.

[0148] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A fiber-reinforced polyurethane / polyisocyanurate foam block (20) for the insulating body (30) of a sealed insulating tank, the fiber-reinforced foam block (20) having a density of 30 to 300 kg / m ３ and an average fiber density T expressed as the weight of the fibers (10) relative to the total weight of the fiber-reinforced polyurethane / polyisocyanurate foam block (20). ｆ is 1% to 60% by weight, and the fiber reinforced polyurethane / polyisocyanurate foam block (20) exhibits a width L of at least 10 centimeters and a thickness E from the lower surface of the block (20) to its upper surface, the thickness E being at least 10 centimeters, the fiber reinforced polyurethane / polyisocyanurate foam block (20) being composed of cells for storing gas, - said foam block (20) comprises, along its thickness E, two peripheral zones (21, 22), one called upper zone (21) extending from said upper face of said block (20) and the other called lower zone (22) extending from said lower face of said block (20), these two zones (21, 22) each occupying a maximum of 20% along said thickness (E) of said block (20) and separated by a zone called intermediate zone (23); - the peripheral zones (21, 22), being the upper zone (21) and the lower zone (22), have a thickness of 2 / 3≦(T ｆ ｕｐｐ． / T ｆ ｌｏｗ． )≦3 / 2 ｆ ｕｐｐ． and T ｆ ｌｏｗ． Each of them presents, - the fibre density T of said intermediate zone (23); ｆ ｉｎｔ． is smaller than the density of the peripheral zones (21, 22), i.e., T ｆ ｉｎｔ． <T ｆ ｕｐｐ． , and T ｆ ｉｎｔ． <T ｆ ｌｏｗ． And T ｆ ｉｎｔ． ≠ 0, A fiber reinforced polyurethane / polyisocyanurate foam block (20).

2. the two peripheral zones (21, 22) each occupying at most 10% along the thickness E of the block (20); The fiber reinforced polyurethane / polyisocyanurate foam block (20) of claim 1.

3. the intermediate zone (23) comprises a central zone (26) surrounded by two median zones (24, 25), the central zone (26) occupying a maximum of 20% along the thickness E; The fiber density T of the central zone (26) ｆ ｃｅｎ． is the fiber density T of the median zone (24, 25) ｆ ｍｅｄ． That is, T ｆ ｃｅｎ． ≧1.5T ｆ ｍｅｄ． That is, 3. The fiber reinforced polyurethane / polyisocyanurate foam block (20) of claim 1 or 2.

4. The fiber density T of the central zone (26) ｆ ｃｅｎ． is the fiber density T of the peripheral zones (21, 22), which are the upper zone (21) and the lower zone (22). ｆ ｕｐｐ． and T ｆ ｌｏｗ． For 0.5≦T ｆ ｃｅｎ． / (T ｆ ｕｐｐ． Or T ｆ ｌｏｗ． ), The fiber reinforced polyurethane / polyisocyanurate foam block (20) of claim 3.

5. The density of the fiber reinforced foam block (20) is 50 to 250 kg / m ３ That is, A fiber reinforced polyurethane / polyisocyanurate foam block (20) according to any one of claims 1 to 4.

6. At least 60% of the cells that store gas are elongated or stretched along an axis parallel to the axis of thickness E of the fiber reinforced polyurethane / polyisocyanurate foam block (20); A fiber reinforced polyurethane / polyisocyanurate foam block (20) according to any one of claims 1 to 5.

7. The fibers are made of glass fibers or basalt fibers. A fiber reinforced polyurethane / polyisocyanurate foam block (20) according to any one of claims 1 to 6.

8. The fibers are long and continuous. A fiber reinforced polyurethane / polyisocyanurate foam block (20) according to any one of claims 1 to 7.

9. The average fiber density T ｆ is between 2% and 25%. A fiber reinforced polyurethane / polyisocyanurate foam block (20) according to any one of claims 1 to 8.

10. the lower surface and / or the upper surface (41) of the block presents anchors (40) that are engageable with engaging means of the insulating body (30) to fix the foam block to the body (30), the anchors (40) being composed of a material different from the fiber reinforced polyurethane / polyisocyanurate foam or the fibers contained in the fiber reinforced polyurethane / polyisocyanurate foam block (20); A fiber reinforced polyurethane / polyisocyanurate foam block (20) according to any one of claims 1 to 9.

11. a tank integrated into a support structure comprising at least one sealed, insulated tank comprising at least one sealed metal membrane made up of a number of metal sheets or plates, which may be provided with corrugations, and an insulating body (30) comprising at least one insulating barrier adjacent to said membrane, or - a tank of type A, B or C according to the definition of the IGC Code, comprising at least one insulating body (30); A sealed insulated tank (71) consisting of: The insulating body (30) comprises a plurality of fiber reinforced polyurethane / polyisocyanurate foam blocks (20) according to any one of claims 1 to 10. A sealed insulated tank (71).

12. A ship (70) for transporting cryogenic liquid products comprising at least one hull (72) and one sealed insulated tank (71) according to claim 11, wherein if said tank (71) is a type A, B or C tank as defined by the IGC Code, said tank (71) is located in said hull or on board said ship (70).

13. A transfer system for a cryogenic liquid product comprising a vessel (70) according to claim 12, a thermally insulated pipe (73, 76, 79, 81) arranged to connect the tank (71) installed in the hull of the vessel to a floating or land-based storage unit (77), and a pump for driving a flow of the cryogenic liquid product from the floating or land-based storage unit to the vessel (71) or from the vessel (71) to the floating or land-based storage unit via the thermally insulated pipe.

14. 13. The process of offloading a vessel (70) according to claim 12, wherein the cryogenic liquid product is transported from a floating or land-based storage unit (77) to the vessel (71) or from the vessel (71) to the floating or land-based storage unit (77) via thermally insulated pipes (73, 76, 79, 81).

15. A process for preparing a fiber reinforced polyurethane / polyisocyanurate foam block (20) for an insulating body of a closed insulating tank according to any one of claims 1 to 10, comprising: a) mixing (12) the chemical components necessary to obtain a polyurethane / polyisocyanurate foam, said components including reactants for obtaining the polyurethane / polyisocyanurate, optionally at least one reaction catalyst, optionally at least one emulsifier, and at least one blowing agent; b) impregnating a plurality of fiber reinforcements (10) by gravity flow of said mixture of chemical components (12), said fiber reinforcements being arranged in overlapping layers and exhibiting variable fiber density, said fiber reinforcements (10) extending essentially along a direction perpendicular to the direction of gravity flow; c) forming and expanding the fiber reinforced polyurethane / polyisocyanurate foam, The expansion of the fiber reinforced polyurethane / polyisocyanurate foam is by free expansion, i.e., not restricted by the volume of at least one closed section, or the expansion of the fiber reinforced polyurethane / polyisocyanurate foam is physically restricted by the walls of a double belt laminator, forming a tunnel surrounding the expanding fiber reinforced foam to obtain the fiber reinforced polyurethane / polyisocyanurate foam block (20); A process for preparing a fiber reinforced polyurethane / polyisocyanurate foam block (20), comprising:

16. step c) is carried out by free expansion upwards, the upper zone (21) being formed independently immediately after cutting of the free expanding surface to form the foam block (20); 16. A process for preparing the fiber reinforced polyurethane / polyisocyanurate foam block (20) of claim 15.

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