RU2799199C2 - Block of polyurethane/polyisocyanurate foam of the heat-insulating tank body and method for its preparation - Google Patents

Abstract

FIELD: polymers; transport containers.

SUBSTANCE: present invention relates to a group of inventions: a block of fiber-reinforced polyurethane and/or polyisocyanurate foams installed in a heat-insulating housing of a sealed and heat-insulated tank; sealed and heat-insulated tank; a vessel for transporting a cold liquid product; cold liquid product transportation system; method of loading or unloading the vessel; method for preparing a block of fiber-reinforced polyurethane/polyisocyanurate foam. This block has a density of 30 to 300 kg/m³. The block has an average fiber density T_f from 1 to 60% by weight of the fibers. The block has a width L from 10 to 500 cm and a thickness E from the lower surface of the block to its upper surface from 10 to 100 cm. The block consists of gas storage cells. The block contains, in its thickness E, two peripheral zones, one of which is considered to be upper, continuing from the upper surface of the block, and the other is considered to be lower, continuing from the lower surface of the block. Each of these two zones represents no more than 20% of the thickness E of the block, and they are separated by a zone that is considered to be intermediate. The peripheral zones, upper and lower, have a fiber density T_{f top} and T_{f bottom}. So: 2/3 ≤ (T_{f top}/T_{f bottom}) ≤ 3/2. Density of fibers T_{f mid} of the middle zone is less than the densities of the peripheral zones, i.e.: T_{f mid} < T_{f top} and T_{f mid} < T _{f bottom}. A method for preparing a fiber-reinforced polyurethane/polyisocyanurate foam block of a thermally insulating body of a sealed and thermally insulated tank includes: a) mixing polyurethane/polyisocyanurate reactants, optionally at least one reaction catalyst, optionally at least one emulsifier, and at least one blowing agent; b) impregnating with the aid of a gravity flow mixture of reagents fibrous reinforcements arranged in superimposed layers and exhibiting variable fiber densities, the fibrous reinforcements being arranged perpendicular to the direction of the gravity flow; c) making and expanding fiber-reinforced polyurethane/polyisocyanurate foam. The expansion of fiber-reinforced foam is considered to be free expansion, i. without limitation imposed by the volume of a closed section on at least one surface, or the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam is physically limited by the walls of the two-belt laminator. A sealed and thermally insulated tank consists of a tank built into a supporting structure containing a sealed and heat-insulated tank containing at least one sealed metal membrane, consisting of a group of metal ribs or metal plates that may contain corrugations, and a heat-insulating housing containing a block reinforced with fibers polyurethane/polyisocyanurate foam. A ship for transporting a cold liquid product includes at least one hull and one sealed and heat-insulated tank.

EFFECT: effective performance.

16 cl, 8 dwg, 4 tbl, 1 ex

Description

[1] The object of the invention are blocks of fiber-reinforced polyurethane (PUR) and/or polyisocyanurate (PIR) foams installed in a thermally insulating housing, which should demonstrate, taking into account their specific applications, very specific mechanical and thermal properties, while being as economical as possible for production, these foam blocks being used inside a tank built into a membrane structure (also called an embedded tank), or a self-supporting/semi-supporting type A, B or C tank, serving to contain extremely cold fluids, called cryogenic fluids, such as, in in particular liquefied natural gas (LNG) or liquefied petroleum gas (LPG).

[2] The present invention relates in particular to a sealed and thermally insulated tank using such foams, a ship equipped with at least one such tank, a method for loading/unloading such a ship, and a system for transporting a liquid product contained in such a ship.

[3] The present invention also relates to a process for preparing these foam blocks from at least one polyisocyanate and at least one polyol.

[4] Polyurethane (PUR) foam is a cellular insulator composed of small gas-storing cells that may have low thermal conductivity. PUR foam is used in a very wide range of applications, such as in the automotive industry, as flexible PUR foam, or in thermal insulation as rigid PUR foam. Formation of foams of the polyurethane type is well known to the person skilled in the art. Their formation involves a multicomponent reaction between a polyol (a compound bearing at least two hydroxyl groups), a polyisocyanate (a compound bearing at least two isocyanate-NCO functional groups) and an expanding agent, also referred to as a blowing agent. This condensation reaction is particularly catalyzed by compounds having a basic and/or nucleophilic nature, such as tertiary amines, or by metal-carboxylate coordination complexes, such as tin or bismuth salts. The polyols commonly used in the manufacture of PUR foams are polyether polyols or polyester polyols. Thus, a large number of compounds are needed to form a PUR foam.

[5] Polyisocyanurate (PIR) and polyurethane/polyisocyanurate (PUR-PIR) foams are also used in the construction (construction/renovation) industry and show the advantage of providing better fire retardant properties as well as greater compressive strength than PUR foams. The method of formation of these foams is similar to the method of formation of PUR foams. This is due to the fact that the production of PUR, PIR and PUR-PIR foams depends on the ratio of isocyanate and polyol.

[6] PUR, PIR and PUR-PIR foams are well known to the person skilled in the art; however, the addition of fibers raises specific technical problems, such as the need for good impregnation of the fibers, to the point that such foams exhibiting, at least locally, a relatively substantial fiber content do not currently exist.

[7] In fact, in the art of using such foams for an insulating tank shell, said shell is subjected to very low temperatures on its surface facing the interior of the tank, for example, approximately -160°C in the case of LNG, while the outside of the tank, typically the hull of a ship, often exhibits a much higher ambient temperature, at least equal to and even much higher than the outside air or sea temperature, considered to be about 20°C.

[8] Thus, the block of PUR, PIR and PUR-PIR foam used in the thermal insulation shell of such a tank undergoes, during loading of an extremely cold fluid, called cryogenic fluid, a very large temperature difference across its thickness, which causes non-uniform compression phenomena. foam block. This non-uniform compression of the foam block causes a bimetallic effect which causes the block to settle along its longitudinal axis - the two ends tend to rise significantly - due to the uneven compression of the block across its thickness. Since the foam block is usually fixed mechanically or by adhesive bonding, this settling significantly reduces the performance mechanical properties of the PUR, PIR and PUR-PIR foam block and even the local thermal properties of the heat-insulating casing (comprising the foam block of the invention).

[9] This phenomenon of bimetallic effect or foam block settling has increased in recent years due to the fact that the thickness of the foam blocks forming the thermal insulation has been increased, sometimes quite significantly, for such tanks containing cryogenic liquid. In particular, when these tanks contain a double layer of thermal insulation, usually referred to as "main" and "auxiliary" layer (and this said auxiliary layer is located farthest from the cryogenic liquid), the thickness E of the auxiliary thermal insulation has increased quite significantly in modern designs, for example, type Mark . Thus, the thickness E of the auxiliary thermal insulation layer has changed from 170 mm (millimeters) in the Mark III design to 300 mm in the Mark III Flex design and then to 380 mm in the Mark III Flex+ design.

[10] This bimetallic effect or this subsidence of the auxiliary thermal insulation layer has particularly detrimental structural consequences for the thermal insulation shell of the sealed and thermally insulated tank when the thickness of this auxiliary layer increases significantly relative to the thickness of the main thermal insulation layer.

[11] Designs such as those described in FR2882756, WO2017/202667 and JP2005225945 are known, but none provide a satisfactory solution to the particular technical problems outlined above.

[12] Currently, there is no block of polyurethane and/or polyisocyanurate foam, fiber-reinforced or non-fiber-reinforced, which would effectively solve this problem, in other words, there is no block of PUR, PIR and PUR-PIR foam that demonstrates thermomechanical stability between its initial state (in a homogeneous thermal environment) and its operating state, that is, when it is used in a tank containing a cryogenic liquid.

[13] To overcome this problem of deformations or geometrical instability between these two states of the foam block, special shaped foam blocks are currently produced, in particular, incorporating cutouts or having reduced dimensions, so as to limit the thermal deformation of each of the (small) volumetric elements or (small) foam blocks within the allowable range. The need to produce these small blocks of foam entails a large amount of cutting, arranging and joining them together at a significant cost. Moreover, the presence of numerous expansion joints significantly worsens the thermal performance of the tank.

[14] In addition, in certain embodiments of tank enclosures, existing foam blocks are placed in a container, typically a box, made from wood, plywood such as fir, birch, or beech. In these embodiments, the bottom and top surfaces of the foam block are adhesively bonded to the inside surface of the container so as to position the blocks correctly. However, during cooling, i.e. when the tank is in the state of use/operation (the tank contains cryogenic liquid), the central part or the part in the center of the foam block in this case is significantly compressed, while the upper and lower zones of the block are limited by their adhesive connection with the inner walls container. Due to the fact that the coefficient of thermal contraction of the foam is much higher than that of plywood, this phenomenon leads to deformation of the shape of the block, when it is in the state of use / operation, the side ends of which show a substantially arc profile (with the shape of an arc or reverse arc ), which thus creates empty spaces between the foam block and its adjacent adjacent members or side walls of the plywood container. These empty foam spaces can lead to undesirable thermal convection phenomena because they proportionally degrade the thermal insulation properties of the tank's insulating shell.

[15] The present invention also aims to provide a solution to this problem specific to certain uses of a block of polyurethane (PUR) and/or polyisocyanurate (PIR) foam.

[16] It is in this context that the applicant company has succeeded in developing a process for the production of polyurethane (PUR) and/or polyisocyanurate (PIR) foams containing significant amounts of fibers, which allows the production of a fiber-reinforced foam exhibiting excellent mechanical and thermal properties while maintaining throughout the foam block, the integrity of its shape/structure when the block is in use, that is, in a very different thermal environment between its two, upper and lower, surfaces.

[17] Thus, the present invention aims to overcome the shortcomings of the prior art by providing a particularly efficient solution for the industrial production of possibly (very) large sizes of fiber-reinforced PUR/PIR foam, the mechanical/thermal properties of which are optimal and at least substantially similar to between its initial state - at rest, when the foam block is in a substantially homogeneous thermal environment - and its state of use/operation, in which the foam block is in a very heterogeneous thermal environment, with the temperature difference between its upper surface (tank contents side) and its lower surface (sides outside the tank), considered through the thickness of the block, is at least equal to 80°C and even at least equal to 100°C.

[18] The applicant company, after various studies and analyzes, has developed a block of fiber reinforced polyurethane (PUR) and/or polyisocyanurate (PIR) foam and its preparation, capable of solving technical problems associated with a very significant change in the thermal environment of the PUR / PIR block foam during its use.

[19] Preferably, it is also possible, according to the preferred embodiment, to greatly reduce the production cost of such fiber reinforced foam by greatly reducing material loss from the foam block, usually required in the prior art during cutting of the foam block in order to obtain the desired dimensions ( parallelepiped).

[20] Thus, the present invention relates to a fiber-reinforced polyurethane/polyisocyanurate foam block of a heat-insulating body of a sealed and thermally insulated tank, wherein the density of the fiber-reinforced foam block is from 30 to 300 kg/m ³ , the fiber-reinforced polyurethane/polyisocyanurate foam block exhibits an average density fibers T _f from 1% to 60% by weight of the fibers and exhibits a width L of at least ten centimeters, preferably from 10 to 500 centimeters, and a thickness E from the lower surface of said block to its upper surface of at least ten centimeters, preferably from 10 up to 100 centimeters, and the block of fiber-reinforced polyurethane/polyisocyanurate foam consists of cells that store a gas, preferably having a low thermal conductivity.

[21] The block of fiber-reinforced polyurethane/polyisocyanurate foam consists, at least 95% by weight of said block, of gas storage cells, preferably having a low thermal conductivity, of polyurethane/polyisocyanurate foam and fibers.

[22] The foam block according to the invention consists (exclusively) of polyurethane (PUR) and/or polyisocyanurate (PIR) foam, of fibers that are preferably of a single nature, such as glass fibers, and of gas trapped in the cells, and optionally of a minimum parts, for example, fillers or other functional stimulants, i.e. for the latter, a maximum of 5% by weight and even preferably a maximum of 2% or 1% by weight of a block of foam according to the invention (a block of fiber-reinforced polyurethane/polyisocyanurate foam in this case consists, at least 98% or 99% by weight of said block, of gas storage cells made of polyurethane/polyisocyanurate foam and fibres). This is due to the fact that the block of foam according to the invention is obtained:

- in one operation for the preparation of foam (mixing the reaction ingredients, optional fillers/stimulants, with fibers), preferably in a double belt laminator (DBL);

- for the above operation, supplemented by the operation of cutting the usually upper surface of the block for adhesive bonding of the peripheral zone, as described below.

[23] The foam block according to the invention is characterized in that:

- the foam block contains, in its thickness E, two peripheral zones, one of which is considered to be upper, extending from the upper surface of the block, and the other is considered to be lower, extending from the lower surface of the block, and each of these two zones represents no more than 20% of the thickness E of the block , and they are separated by a zone that is considered intermediate; And

- peripheral zones, upper and lower, respectively show the density of the fibers T _{f top.} and T _{f lower.} so that: 2/3 ≤ (T _{f top} /T _{f bottom} ) ≤ 3/2; And

- fiber density T _{f prom.} the intermediate zone is less than the densities of the peripheral zones, i.e.: T _{f prom.} <T _{f upper} and T _{f prom.} <Tf _lower

[24] The present invention is particularly, but not exclusively, intended for use in the case where the foam block is installed in an auxiliary layer, commonly referred to as "ancillary". In this application, preferably, the foam block exhibits a thickness of at least twenty-five (25) centimeters (cm), and even more preferably at least 30 or 35 cm.

[25] The terms "upper" and "lower" are understood to mean the feel or direction given to the foam block once it is in position in the tank's insulating shell. Thus, the top or surface of the foam block is that which is located near or to the side of the tank container when the heat-insulating body is located in the tank, while the bottom or surface of the foam block is that which is located towards the outside of the tank or to the side the outer side of the tank, that is, in particular, towards the hull of the vessel in the case when the tank is built into or installed in the ship for transport and/or storage of cryogenic liquid.

[26] Thus, it is clear that during the manufacture or preparation of the foam block, these concepts or the terms "upper" or "lower" do not yet have a meaning, since the foam block is not yet installed in the insulating body of the tank. In other words, it is entirely possible to prepare foam blocks according to the invention such that they are produced at the outlet of their preparation/manufacturing line in a position opposite to their final installation/assembly position in the tank's insulating shell.

[27] The expression "in its thickness E" is understood to mean, in relation to the various peripheral, intermediate and even middle/central zones, which are described below, that each of these zones represents a certain volume of a block of fiber-reinforced polyurethane (PUR) and/or polyisocyanurate (PIR) of the foam, considered by making a section through the thickness E, as shown in particular in Figures 3 and 4, in order to form a section of the block showing the same width L and the same length - only the thickness differs - as foam block according to the invention.

[28] The expression "gas storage cells" is understood to mean that the polyurethane/polyisocyanurate foam exhibits closed cells containing a gas, preferably exhibiting low thermal conductivity, derived from the gas injected during the nucleation step of the reaction mixture, or occurring, directly or indirectly, from a chemical or physical blowing agent.

[29] The term "fiber(s)" or the expression "fibrous reinforcement" is understood to mean that the fibers can be presented in two different forms:

or in the form of at least one web of fibers in which the fibers are completely aligned along at least one direction, in other words, the fibers show at least one preferred fiber direction. The expression "fabric of fibers" in itself refers to a clear technical definition known to a person skilled in the art,

- or in the form of at least one mat of fibers, in which the fibers do not show a given orientation, in other words, these fibers are oriented essentially uniformly along the main plane of the layer of the mat. Again, the expression "fiber mat" itself refers to a well-defined technical definition known to a person skilled in the art.

[30] According to one embodiment, the expression "a gas (preferably) having a low thermal conductivity" is understood to mean a gas originating from a blowing agent or as a result of a chemical reaction of the latter, when this agent is considered "chemical", usually carbon dioxide (CO ₂ ), when the chemical blowing agent consists of water or a physical blowing agent such as, for example, molecular nitrogen (N ₂ ), molecular oxygen (O ₂ ), carbon dioxide, hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons and mixtures thereof, and also the corresponding alkyl ethers. Physical blowing agents such as molecular nitrogen N2, molecular oxygen O2 or CO ₂ are in gaseous form. These gases are dispersed or dissolved in the liquid mass of the copolymer, for example under high pressure by means of a static mixer. When the pressure in the system is released, nucleation and bubble growth form a cellular structure.

[31] The expression "average fiber density _Tf " is understood to mean the fiber density expressed as the weight of the fibers relative to the total weight of the block of fiber-reinforced foam without taking into account the variable local percentages (within the block) of these fibers.

[32] The fiber-reinforced foam block is thus compatible with use in tanks built into a supporting structure, as well as in self-supporting/semi-supporting tanks type A, B or C according to IGC (IMO), i.e. as external insulation associated with self-supporting tanks for storing and/or transporting very cold liquids such as LNG or LPG.

[33] Finally, the thermal properties of the fiber-reinforced foam block are at least equal to those of prior art non-fiber-reinforced foam blocks; more precisely, the foam block exhibits a thermal conductivity of less than 30 mW/(m·K) (milliwatt per meter per Kelvin) across the thickness E, i.e. 0.03 W/(m⋅K), preferably less than 25 mW/(m K), even more preferably less than 23 mW/(m K) when measured at 20°C and thermal conductivity less than 20 mW/(m K ) when the top surface of the block is at a temperature of 160°C, the foam block in this case being in use and the tank in which it is placed contains LNG.

[34] Other preferred features of the invention are summarized below:

[35] Preferably, each of the above two peripheral zones represents no more than 10% of the thickness E of the block.

[36] According to a preferred embodiment of the invention, the intermediate zone comprises a central zone surrounded by two middle zones representing no more than 20% of the thickness E, preferably no more than 10% of the thickness E, with the fiber density T _{f center.} this central zone is at least one and a half times higher than the fiber density of the middle zones T _{f environments.} , i.e. T _{f center.} ≥ 1.5Tf _avg. .

[37] This embodiment is shown in the attached Figure 4 and allows the problem of foam shrinkage in the center, that is, the central zone, to be more specifically addressed, while avoiding the bimetallic phenomenon through peripheral zones with a higher fiber density.

[38] According to another characteristic specific to this embodiment, the fiber density T _{f center.} the central zone is defined relative to the fiber density T _{f top.} and T _{f lower.} peripheral zones, upper and lower, so that 0.5 ≤ T _{f center.} /(T _{f low} or T _{f high} ) ≤ 2.

[39] Preferably, the density of the fiber-reinforced foam block is 50 to 250 kg/m ³ , preferably 90 to 210 kg/m ³ . It should be noted here that for foam blocks used in a tank of self-supporting type (types B, C) or semi-supporting type (type A), the density range of the fiber-reinforced foam block is preferably from 30 to 90 kg/m ³ , while in the case of membranes, the preferred density range is from 90 to 210 kg/m ³ .

[40] Preferably, at least 60%, preferably at least 80% of the above gas storage cells, preferably having a low thermal conductivity, exhibit a shape elongated or elongated along an axis parallel to the thickness E axis of the fiber-reinforced polyurethane/polyisocyanurate foam block.

[41] According to one possibility proposed by the invention, the fibers consist of glass fibers or basalt fibers, preferably glass fibers.

[42] Preferably, the fibers are long to continuous fibers.

[43] The expression "fibers are long to continuous fibers" (or "long-continuous fibers") is understood to mean that the fibers, or, if appropriate, the aggregation of a collection of fibers (fibers bonded by adhesive or bonded to each other), are all or at least 90% of the fibers, considered individually or in a cluster forming the equivalent of one fiber, based on the total weight of said fibers, exhibit a length of at least five (5) centimeters (cm).

[44] Preferably, the average fiber density _Tf is 2% to 25%, preferably 6% to 20%.

[45] Preferably, the foam block of the invention is in the form of a parallelepiped or a cube.

[46] Here, it is clear that a foam block exhibiting such a parallelepiped or cube shape may exhibit one or more local bulges, for example in the form of anchor elements presented in the following, or also, conversely, empty or hollow areas, while still being able to be described as having the shape of a parallelepiped or a cube.

[47] Preferably, the bottom surface and/or the top surface of said block exhibits (shows) anchoring elements capable of engaging with a heat-insulating body engagement means (not shown in the attached figures) in order to attach or anchor the foam block to said body, and preferably said anchor elements are made of a material different from the material of the foam or the material of the fibers.

[48] These anchor elements are preferably metal elements (these anchor elements can also be made of plastic/polymers or composites combining one or more polymers with ceramic and/or metal materials), e.g. /opening, for example, L-shaped, so as to engage with the element or part of the heat-insulating housing surrounding or enclosing the block of fiber-reinforced foam. This part of the heat-insulating shell may consist of a metal membrane for sealing the container, for example made of stainless steel or manganese-based in the case of a membrane tank, or of a vapor barrier (having the technical function of sealing the outside of the tank from the environment) in the case of self-supporting or semi-supporting tanks of the type A, B or C. In one possibility proposed by the invention, this element or this part of the thermal insulation housing (in a membrane tank) exhibits a cutout or similar element designed to form an engagement with a section of the anchor element to mechanically support or hold a block of fiber reinforced foam with other elements of the thermal insulation block. Of course, these anchor elements can also have the function of anchoring the foam block to the shell in the case of a membrane tank or to a self-supporting structure in the case of a self-supporting tank of type A, B or C, it being understood that these anchor elements in this case are anchor elements that are present on the bottom surface of the foam block.

[49] In the context of the present invention, these anchor elements are inserted at least partially into the fibrous reinforcements forming the bottom or top layer of the fiber reinforcement stack, so as to allow them to be placed on surfaces once the foam block has been prepared/completed, without, however, protrusions from the specified surface.

[50] Preferably, the fiber reinforced foam block of the invention contains a flame retardant additive in a proportion of 0.1% to 5% by weight of an organophosphorus type, preferably 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 a mixture thereof, or inorganic type flame retardant, preferably red phosphorus, expandable graphite, alumina hydrate, antimony trioxide, oxide arsenic, ammonium polyphosphate, calcium sulfate or cyanuric acid derivatives or a mixture thereof.

[51] The invention also relates to a sealed and thermally insulated tank built into a supporting structure, which consists of:

- a tank built into a supporting structure, containing a sealed and heat-insulated tank containing at least one sealed metal membrane, consisting of a group of metal ribs or metal plates that may contain corrugations, and a heat-insulating housing containing at least one heat-insulating barrier adjacent with the specified membrane, or

- tank type A, B or C as defined in the IGC code, containing at least one thermal insulation shell.

[52] The tank according to the invention is characterized in that the heat-insulating body contains a group of blocks of fiber-reinforced polyurethane/polyisocyanurate foam, which are briefly described above.

[53] The expression "IGC code" is understood to mean "International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk", well known to the person skilled in the art, as well as the types B and C tanks mentioned.

[54] It should be noted that, in particular, in the IGC Code it is possible to use the expression “membrane tank” instead of the expression “built-in tank” to refer to the same category of tanks, which are equipped, in particular, tankers transporting and / or storing at least partially liquefied gas. "Membrane tanks" are built into a supporting structure, while Type A, B, or C tanks are considered self-supporting or semi-supporting (especially Type A).

[55] Finally, the invention also relates to a vessel for transporting a cold liquid product, comprising at least one hull and one sealed and thermally insulated tank, as briefly described above, located in the hull or installed on said vessel, if said tank is type A , B or C as defined in the IGC code.

[56] Preferably, in the case where the tank consists of a tank built into a supporting structure (membrane tank), such a vessel contains at least one sealed and insulated tank, as described above, containing two sealing barriers in series: one, main, in contact with the product contained in the tank, and another, auxiliary, located between the main barrier and the supporting structure, preferably formed by at least part of the walls of the vessel, and these two sealing barriers alternate with two heat-insulating barriers or one heat-insulating barrier located between the main barrier and the carrier design.

[57] Such tanks are usually designated as built-in tanks according to the International Maritime Organization (IMO) code, such as, for example, NO type tanks, including types NO 96 ^® , NO 96L03 ^® , NO 96L03+ or NO 96 Max, or Mark III ^® , Mark III ^® Flex or Flex+, preferably NO tanks.

[58] Preferably, the reservoir, considered to be a membrane type or type A, B or C, contains liquefied natural gas (LNG) or liquefied natural gas (LG).

[59] The invention also relates to a cold liquid product transport system comprising a ship as defined above, insulated pipes positioned to connect a vessel-mounted tank to a floating or shore storage facility, and a pump to drive the flow cold liquid product through insulated pipes from the floating or onshore storage facility to the ship or to the floating or onshore storage facility from the ship.

[60] The invention also relates to a method for loading or unloading a ship as defined above, wherein a cold liquid product is transported through insulated pipes from a floating or onshore storage facility to a ship or to a floating or onshore storage facility from the ship.

[61] The present invention also relates to a method for preparing a block of fiber-reinforced polyurethane/polyisocyanurate foam of a heat-insulating body of a sealed and heat-insulated tank, which is briefly described above, characterized in that it contains the steps in which:

a) mixing the chemical components necessary to obtain a polyurethane/polyisocyanurate foam containing reagents for the production of polyurethane/polyisocyanurate, optionally at least one reaction catalyst, optionally at least one emulsifier and at least one blowing agent,

b) impregnating with the help of the gravity flow of the above mixture of chemical components a group of fibrous reinforcements arranged in superimposed layers and showing variable fiber densities, the fibrous reinforcements continuing essentially in a direction perpendicular to the direction of said gravity flow,

c) form and expand fibre-reinforced polyurethane/polyisocyanurate foam,

wherein the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam is considered to be free expansion, i. e. without limitation imposed by the volume of the closed section on at least one surface, preferably the top surface, or

expansion of the fibre-reinforced polyurethane/polyisocyanurate foam is physically constrained by the walls of the two-belt laminator, preferably physically constrained by the walls of the two-belt laminator forming a rectangular tunnel with a lateral wall spacing of L and a horizontal wall spacing of E, thus surrounding the expanding fiber-reinforced foam so as to obtain the above block of fiber-reinforced polyurethane/polyisocyanurate foam.

[62] The expression "foam start time" is understood to mean the time required, counting from the moment of mixing of the chemical components, for the latter to start the polymerization reactions, and, therefore, for the mixture of components to start the expansion and cross-linking step c) (= formation of fiber-reinforced PUR/PIR foam). This foam start time is part of the information well known to the person skilled in the art. In other words, the foam onset time is the time elapsed before the mixture turns white due to bubble nucleation (gas storage cells) and foam expansion after mixing the chemical components at ambient temperature. The start time of foam formation can be determined visually or by means of an ultrasonic sensor detecting a change in thickness indicative of foam formation.

[63] The expression "fibrous reinforcements continue essentially in a direction perpendicular to the direction of the gravitational flow of the mixture of chemical components" is understood to mean that these fibrous reinforcements are in the form of a layer of small thickness, continuing during step b) impregnation along a plane perpendicular to the direction of flow of the specified mixtures of components. Thus, as can be seen in Figure 1, a group of fibrous reinforcements, showing a width L and arranged in superimposed layers, are entrained in the longitudinal direction L, while a mixture of chemical components is applied to the fibrous reinforcements from a dispensing device, providing /allowing the gravitational flow of a mixture of chemical components. In other words, the mixture of chemical components, optionally exiting under pressure from the dispenser, falls under the action of at least its own weight onto the stacked layers of fibers, thus impregnating these fibrous reinforcements from the top layer to the bottom layer.

[64] According to one embodiment of the invention, in the case where the expansion step c) is performed by free expansion, at least one of the peripheral zones, preferably the upper zone, is formed independently and fixed once a cut has been made on at least the free expansion surface. , to form said block of foam.

[65] The use of a chemical blowing agent in the composition of the invention can be combined with the use of a physical blowing agent. In this case, the physical blowing agent is preferably mixed in liquid or supercritical form with the expandable (co)polymer composition and then converted to the gaseous phase during the expansion step of the PUR/PIR foam.

[66] Chemical and physical blowing agents are well known to the person skilled in the art, who chooses them in suitable amounts depending on the PUR/PIR foam that he wants to get.

[67] The term "polyols" is understood to mean any carbon-based structure bearing at least two OH groups.

[68] Since PUR, PIR and PUR-PIR foams are produced depending on the ratio of isocyanate and polyol, PUR, PIR or PUR-PIR foams will be produced according to this ratio. When the ratio of polyol component to isocyanate component is:

- between 1:1 and 1:1.3 - polyurethane PUR foam will be obtained,

- between 1:1.3 and 1:1.8 - a polyurethane-polyisocyanurate PUR-PIR foam will be obtained,

- between 1:1.8 and 1:2.8 - polyisocyanurate PIR foam will be obtained.

[69] Polyisocyanates suitable for the formation of PUR, PIR and PUR-PIR foam are known to the person skilled in the art and contain, for example, aromatic, aliphatic, cycloaliphatic and arylaliphatic polyisocyanates and mixtures thereof, preferably aromatic polyisocyanates.

[70] Examples of polyisocyanates suitable within the scope of the present invention include aromatic isocyanates such as the 4,4'-, 2,4'- and 2,2'-isomers of diphenylmethane diisocyanate (MDI), any compound resulting from the polymerization of these isomers, toluene-2,4- and -2,6-diisocyanate (TDI), m- and p-phenylenediisocyanate, naphthalene-1,5-diisocyanate; aliphatic, cycloaliphatic or arylaliphatic isocyanates such as 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate (CHDI), bis(isocyanatomethyl)cyclohexane (H6XDI, DDI) and tetramethoxysilene diisocyanate (TMXDI). It is also possible to use any mixtures of these diisocyanates. Preferably, the polyisocyanates are the 4,4'-, 2,4'- and 2,2'-isomers of diphenylmethane diisocyanate (MDI).

[71] In general, during the formation of PUR, PIR or PUR-PIR foams, it is known to add to the mixture containing the polyol, the polyisocyanate and the blowing agent, a reaction catalyst which may, for example, be selected from tertiary amines such as N,N-dimethylcyclohexylamine or N,N-dimethylbenzylamine, or from organometallic compounds based on bismuth, potassium or tin.

[72] According to a preferred embodiment of the invention, preferably, the location of the tunnel walls of the dual belt laminator (DBL) is determined such that limiting the expansion of the fiber reinforced polyurethane/polyisocyanurate foam results in a fiber reinforced polyurethane/polyisocyanurate foam output volume of the dual belt laminator representing from 85% up to 99%, preferably from 90% to 99% of the expansion volume of the same fiber-reinforced polyurethane/polyisocyanurate foam in the case of free expansion without being limited by the walls of such a two-belt laminator. In this case, a foam is obtained whose oval-shaped cells are predominantly oriented along the E axis, resulting in the advantageous properties of resistance to fracture in this direction E (when measured according to ISO 844) in combination with the properties already described in a plane perpendicular to this E axis. Tests and experiments have been performed by the applicant company to determine the broad and preferred ranges mentioned above, but they are not presented here for clarity and brevity.

[73] By means of the above specific parametrization of the restriction on the expansion of the fiber-reinforced PUR/PIR foam in DBL, on the one hand, a block of fiber-reinforced PUR/PIR foam is obtained, in which at least 60%, in general more than 80% and even more than 90% the low thermal conductivity gas storage cells extend longitudinally along an axis parallel to the thickness axis E of the foam block, and in addition to specific choices relating to the characteristics of the fibrous reinforcements and the viscosity of the mixture of chemical components, contribute to the perfect uniformity of the fiber reinforced foam block. These two characteristics - the orientation of the cells and the uniformity of the content of T _f fibers in the block along different, peripheral or central, zones - make it possible to obtain a fiber-reinforced foam block that exhibits excellent mechanical properties through the thickness E (compressive strength) and in the plane perpendicular to the thickness direction ( tensile strength and low coefficient of thermal contraction).

[74] An elongated or elongated shape can be formed by a shape extended in length, meaning that it contains one dimension - its length - that exceeds its other dimensions (width and thickness).

[75] According to another embodiment of the invention, the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam is free, i. without the limitation imposed by the volume of a closed section.

[76] In this example, in contrast to the DBL embodiment of the preparation process of the invention, the production of the fiber-reinforced polyurethane/polyisocyanurate foam is considered to be performed by "free expansion" because the expansion of the fiber-reinforced foam is not limited on at least one side or from at least one expansion surface so that the swelling of the fiber-reinforced foam is free on this side or this surface, in contrast to the shape forming the final volume. Typically, free expansion is accomplished by eliminating the (top) lid while the sidewalls prevent foam from flowing over the sides and the foam naturally swells upwards, possibly beyond the top ends of these sidewalls.

[77] Preferably, after the free expansion step of the fiber-reinforced polyurethane/polyisocyanurate foam, said fiber-reinforced foam is cut to obtain the above fiber-reinforced polyurethane/polyisocyanurate foam block.

[78] According to one possibility proposed by the invention, not shown in the attached Figures, immediately after the stage of impregnation of the fibrous reinforcements, a system for applying pressure (which may, for example, be a system of rollers , of the type designated "pressure rollers"), designed to apply pressure to the upper surface of the accumulation, consisting of the above mixture and fibers. This pressure application system makes it possible, on the one hand, to plan the upper surface of this accumulation and, by means of the pressure applied to the accumulation, contributes to the acceleration of the impregnation of the fibers in the above mixture. This pressure application system may consist of a single or double roller whose relative positions above the fluid collection and possibly below the foam support are adjusted in such a way as to force the liquid accumulation to be distributed completely evenly. Thus, by doing this, an equivalent amount of fluid accumulation is obtained at any point in the section formed by the distance between the two rollers or the upper roller and the conveyor belt. In other words, the main task of this pressure application system is to complement the liquid dispenser in that it contributes to uniformity of the accumulation of liquid in thickness/width to the main part of its expansion.

[79] Preferably, the dynamic viscosity η of the above mixture of components is 30 mPa s to 3000 mPa s (or 0.03 Pa s to 3 Pa s), preferably 50 mPa s to 1500 mPa s (or from 0.05 Pa s to 1.5 Pa s) at ambient temperature (25°C) and atmospheric pressure (1015 MPa).

[80] The dynamic viscosity of a blend of components can be determined by means of a viscometer, such as a Brookfield type, or a capillary viscometer, such as ISO 2555.

[81] In general, it is clear that the object of the present invention uses materials/products available on the market, so that their properties, in particular those relating to their densities or (dynamic) viscosities, are available in the specifications relating to the materials in question/ products.

[82] Preferably, at least 60% of the above gas storage cells, preferably having a low thermal conductivity, exhibit a shape that is elongated or elongated along an axis parallel to the thickness axis E of the fiber-reinforced polyurethane/polyisocyanurate foam block.

[83] Even more preferably, at least 80%, preferably at least 90% of the above gas storage cells, preferably having a low thermal conductivity, exhibit a shape elongated or elongated along an axis parallel to the thickness E axis of the fiber-reinforced polyurethane/polyisocyanurate foam block.

[84] Here it is obvious that this characteristic relating to the elongated shape of the cells storing a gas, preferably having a low thermal conductivity, and their content/proportion in the block according to the invention is more specifically related to the context of the implementation of the method of preparation using DBL, but it is not limited to this at all. scenario. This is because in the case of free expansion, more specifically when there is no top wall/lid to limit the expansion of the fibre-reinforced foam, such an advantageous orientation of the gas storage cells, preferably having a low thermal conductivity, is also obtained.

[85] Preferably, the fibers (fibrous reinforcements) are arranged over the entire width L, and step b) of impregnating the fibers with a mixture of components and a blowing agent in order to obtain a fiber-reinforced polyurethane/polyisocyanurate foam is performed using a controlled liquid dispenser simultaneously over the entire width L .

[86] The term "simultaneously" is understood to mean that the liquid mixture (the reagents and at least the blowing agent) reaches the fibers over a section of width L at the same time throughout this section so that the impregnation of different fibrous reinforcements begins or is carried out along thickness (or height) of the foam block and along the same width section at the same time or at the same speed.

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

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

[89] Under this assumption, propane, n-butane, isobutane, cyclobutane, n-pentane, isopentane, cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, and fluoroalkanes can be exemplified as compounds; wherein the selected fluoroalkanes are those which do not degrade the ozone layer, such as trifluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane and heptafluoropropane. Examples of pterolefins include 1-chloro-3,3,3-trifluoropropene or 1,1,1,4,4,4-hexafluorobutene (eg HFO FEA1100 sold by DuPont).

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

[91] Preferably, the chemical blowing agent consists of water.

[92] Preferably during step a) of mixing the chemical components, the nucleating gas is introduced into at least one polyol compound, preferably by means of a static/dynamic mixer at a pressure of 2 to 25 MPa, the nucleating gas is from 0% to 50% by volume of the polyol, preferably from 0.05% to 20% by volume of the polyol.

[93] Preferably, during step a) of mixing the chemical components, the temperature of each of the polyurethane/polyisocyanurate reactants is 10°C to 40°C, preferably 15°C to 30°C.

[94] Preferably, according to a preferred embodiment of the invention, the final mixing of the streams of polyols, isocyanate and/or blowing agent occurs in the mixing head at low pressure (<2 MPa) or high pressure (>5 MPa) through a dynamic or static mixer.

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

[96] It can also be provided that diethyl ethane phosphonate (DEEP), triethyl phosphate (TEP), dimethyl propyl phosphonate (DMPP), or diphenylcresyl phosphate (DPC) is used in the flame retardant.

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

[98] The description that follows is by way of illustration only and without limitation with reference to the appended Figures, in which:

[99] FIG. 1 is a schematic view illustrating the different steps of the process for preparing a PUR/PIR fiber-reinforced foam block according to the invention.

[100] FIG. 2 is a schematic representation of an embodiment of a controlled liquid dispenser according to the invention.

[101] FIG. 3 is a schematic cross-sectional view of a foam block according to one embodiment of the invention, showing the peripheral zones as well as the intermediate zone.

[102] FIG. 4 is a schematic cross-sectional view of a foam block according to another embodiment of the invention showing the peripheral zones as well as the intermediate zone, the intermediate zone showing two middle zones with a central zone in between.

[103] FIG. 5 is a schematic view of two sets of thermal insulation panels attached to each other, respectively forming a main insulating space and a secondary insulating space for a tank, these panels being formed by a group of fiber reinforced polyurethane/polyisocyanurate foam blocks according to the invention.

[104] FIG. 6 is a partial view of a foam block according to the invention, in which, during its preparation, a group of anchor elements has been placed so as to provide for the fastening or anchoring of said foam block.

[105] FIG. 7 illustrates an embodiment of an anchor element, seen along a schematic section, capable of being inserted into a foam block according to the invention.

[106] FIG. 8 is a schematic sectional view of an LNG tanker tank with two sets of thermal insulation panels of the type shown in Figure 7 and a loading/unloading terminal for this tank installed in this tank.

[107] Preferably, the preparation of the fiber-reinforced PUR/PIR according to the invention is carried out in the presence of catalysts to accelerate the isocyanate/polyol reaction. Such compounds are described, for example, in a document of the prior art entitled "Kunststoffhandbuch, volume 7, "Polyurethane", published by Carl Hanser, 3rd edition, 1993, chapter 3.4.1. These compounds contain amine-based catalysts and organic-based catalysts.

[108] Preferably, the preparation of the PUR/PIR fiber-reinforced foam block 20 of the invention is performed in the presence of one or more stabilizers designed to promote the formation of conventional honeycomb structures during foam formation. These compounds are well known to the person skilled in the art and, by way of example, foam stabilizers containing silicones, such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, may be mentioned.

[109] A person skilled in the art knows the amount of stabilizers from 0.5% to 4% by weight of PUR/PIR foam, which should be used depending on the provided reagents.

[110] According to one possibility proposed by the invention, during step a) of the preparation process, the mixture of chemical components may contain plasticizers, for example, esters of polybasic acids, preferably dibasic esters, carboxylic acids with monohydric alcohols, or may consist of polymeric plasticizers, such as polyesters of adipic, sebacic and/or phthalic acids. The person skilled in the art, depending on the reagents used, will know the amount of plasticizers provided, typically from 0.05% to 7.5% by weight of the polyurethane/polyisocyanurate foam.

[111] Organic and/or inorganic fillers, in particular, reinforcing fillers, can also be provided in a mixture of chemical components, such as siliceous minerals, metal oxides (for example, oxides of kaolin, titanium or iron) and/or metal salts. The amount of these fillers, if present in the mixture, is typically between 0.5% and 15% by weight of the PUR/PIR foam.

[112] It should be noted that the present invention is not intended here to add a technical idea to the formation of PUR/PIR foam, both in terms of the nature of the main chemical components and optional functional agents and their respective amounts. The person skilled in the art knows how to make different types of PUR/PIR fiber-reinforced foam, and the present preparation begins with a specific selection of the characteristics of the fibrous reinforcements, in particular, the density of the fibers in different fibrous reinforcements, as well as with a specific choice of foam for impregnation of these reinforcements.

[113] Thus, the present invention, as set forth herein, is not primarily directed to a new chemical preparation of PUR/PIR fiber reinforced foam, but rather to a new PUR/PIR fiber reinforced foam block 20 in which, through a very specific fiber density distribution across the thickness or height of the block 20, this fiber-reinforced foam block 20 does not suffer any settling or any deformation of its overall parallelepiped shape/structure, other than a slight contraction of its dimensions by a constant factor in all its directions, and preferably no shrinkage at the center of the foam block 20 , probably leading to possible phenomena of thermal convection.

[114] Thus, as can be seen in Figure 1, a group of fibrous reinforcements 10 are unwound and carried in parallel alignment with each other on or over a conveyor belt 11 designed to carry these reinforcements 10 and PUR/PIR foam forming components. This is because the impregnation of the fibrous reinforcements 10 is, in the context of the preferred method for preparing the fiber reinforced foam block 20 of the present invention, under the action of gravity, which means that the mixture of 12 chemical components, blowing agent(s) and optional other functional agents, used to produce PUR/PIR foam is poured from a liquid dispenser located above the fiber reinforcements 10 directly onto the fibers 10.

[115] Thus, the above mixture 12 must impregnate all layers of fibrous reinforcements 10, regardless of whether it touches several mats or several fabrics in relation to these reinforcements, in a very uniform manner during the time t _from the start of foam formation, so that the start of expansion of the PUR The /PIR foam occurs after or at the earliest at the very moment when all the fibrous reinforcements 10 are precisely impregnated with the mixture 12. By doing this, the expansion of the PUR/PIR foam is achieved while maintaining an ideal specific distribution of the fibers 10 within the volume of the PUR/PIR foam block 20 so that obtain the desired fiber density gradient.

[116] The object of the present invention is achieved by arranging fibrous reinforcements parallel to each other, ie. in the form of superimposed layers, and each of these reinforcements shows a greater or lesser density of fibers compared to others. Thus, fibrous reinforcements intended for the peripheral zones 21, 22 and even for the central zone 26 show a higher fiber density than for the intermediate zone 23 and even the middle zones 24, 25 in the embodiment where the central zone 26 is present.

[117] More precisely, the peripheral zones 21, 22, and optionally the central zone 26, exhibit fiber densities within comparable ranges or intervals that have a high fiber density. Thus, it can be determined that the fiber density ratio for these zones 21, 22, 26 is contained in the inequalities defined below:

2/3 ≤ Tf _top /Tf _lower ≤ 3/2 and T _{f prom.} <T _{f upper} , T _{f lower} : in the case of two peripheral zones 21, 22 and an intermediate zone 23 shown in Figure 3;

2/3 ≤ T _{f center.} /(T _{f low} or T _{f high} ) ≤ 3/2 and T _{f mid.} <Tf _lower , T _{f top} , T _{f center.} : in the case of two peripheral zones 21, 22 and an intermediate zone 23 formed by a central zone 26 and two middle zones 24, 25 shown in Figure 4.

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

[119] In contrast, the intermediate zone 23 (when the central zone 26 is absent) and the middle zones 24, 25 (when the central zone 26 is present) exhibit relatively lower 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 4% to 11% by weight of the fibers relative to the local weight in the PUR/PIR foam block 20.

[120] If zones 21, 22, 26 having a high fiber density are compared 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 of at least greater than the fiber density of low fiber density zones 23 or 24, 25, and even preferably two to three times the fiber density of low fiber density zones 23 or 24, 25.

[121] In the context of the invention, the start time of the foam components of the mixture 12 in order to form a PUR/PIR foam is known to the person skilled in the art and is chosen such that the conveyor belt 11 brings the accumulation formed from the mixture of 12 components, blowing agent and fibers 10, for example, to a two-belt laminator, not shown in the attached figures, when the expansion of the foam has just begun, in other words, the expansion of the PUR/PIR foam in this case ends in a two-belt laminator.

[122] In such a dual belt laminator (DBL) embodiment, a pressure application system using one or two rollers is optionally located in front of the dual belt laminator, i. between the area for impregnation with a mixture of fibers and a two-belt laminator. In the case of using DBL, expansion of the foam volume is performed in the laminator when the expansion volume of this foam reaches from 30% to 60% of the expansion volume of this same foam, when the expansion remains free, i.e. without any limitation. By doing this, the dual belt laminator will be able to limit the expansion of the PUR/PIR foam in its second expansion phase when the latter is close or relatively close to its maximum expansion, i.e. when its expansion brings the foam closer to all walls of the dual belt laminator forming a rectangular or square tunnel. According to another variant of the presentation of specific preparation choices according to the invention, the point of gelation of the mixture of components, that is, the moment when at least 60% polymerization of the mixture of components is reached, in other words, 70%-80% of the maximum expansion of the volume of the mixture, necessarily occurs in a two-belt laminator, possibly during the second half of the length of the two-strip laminator (i.e., closer to the exit of the laminator than to the entrance of the latter).

[123] With regard to the function of simultaneously issuing a mixture of 12 chemical components and a blowing agent across the entire width L of the fibrous reinforcements 10, it is provided here by means of a controllable liquid issuing device 15, visible in Figure 2. Such an issuing device 15 contains a supply channel 16 for accumulation, formed from a mixture of 12 chemical components and at least a blowing agent, from a tank forming a mixer for reagents, not shown in the attached figures, in which, on the one hand, all chemical components and blowing agent are mixed, and, on the other hand, perform, in particular, nucleation and even heating of such a mixture. This accumulation of liquid, formed from a mixture of 12 chemical components and a foaming agent, is then distributed under pressure through two channels 17, continuing transversely corresponding to the end in two identical dispensing plates 18, extending across the width L (each of which shows a length essentially equal to L / 2) containing a group of nozzles 19 for flowing said mixture 12 over fibrous reinforcements 10. These flow nozzles 19 consist of holes of calibrated cross-section showing a predetermined length. Thus, the length of these flow nozzles 19 is set so that the liquid exits at an identical flow rate between all nozzles 19 so that the impregnation of the fibrous reinforcements 10 occurs at the same time or simultaneously over the section width L of the fibrous reinforcements 10 and that the surface density liquid applied at right angles with each nozzle was the same. When doing this, if a section of width L of the fibers 10 is considered, the latter are impregnated simultaneously so that the layers of fibers 10 are impregnated with mixture 12 at all points of this section in an identical way, which contributes to the production of a block 20 of fiber-reinforced foam at the exit of the two-belt laminator, in which the local density fibers exactly corresponds to the fiber density of each of the layers of fibrous reinforcements superimposed on each other at the moment of the gravitational flow of the mixture 12.

[124] The controllable liquid dispensing device 15 shown in this Figure 2 is an exemplary embodiment that uses two identical dispensing plates 18, but it will be possible to provide a different design, provided that the function of simultaneously dispensing liquid across the width of the fibers 10 is achieved. Of course, the main technical characteristic used in this example lies in the different lengths of the flow nozzles 19, tending to a greater or lesser extent depending on the route or path of the liquid mixture 12 from the supply channel 16 of the dispenser 15, if we talk about the considered flow nozzle 19 .

[125] One of the important aspects to achieve good impregnation of the fibrous reinforcements 10 immediately before the time t _from the beginning of the formation of the PUR/PIR foam is the choice of the specific viscosity of the liquid (consisting of a mixture of 12 chemical components and a blowing agent), which must be associated with specific characteristics of different fibrous reinforcements, which may vary depending on the density of the fibers. The chosen viscosity range, as well as the permeability characteristics of the fiber reinforcements, must allow good liquid penetration into the first layers of fibers 10 in order to reach the next layers up to the last layer (the bottom layer of fibers 10, i.e. the layer that is located lowest in the fiber stack). reinforcements), so that the time t _i of the impregnation of the fibers 10 is within the time period specified by the chemical components, corresponding essentially to the time t _c of the start of foam formation, but always less than it. The viscosity of the mixture of 12 components is chosen, for example, by heating, adding plasticizers and/or more or less nucleation so that the impregnation of all fibers 10 with a mixture of 12 chemical components and a blowing agent over a section of width L is obtained immediately before the start time of foam formation, that is, before or immediately prior to the expansion of the PUR/PIR foam.

[126] The fiber-reinforced foam block 20 is intended for use in a very specific environment and thus must guarantee specific mechanical and thermal properties. Thus, the fiber-reinforced foam block 20 obtained by the preparation according to the present invention usually forms part of the heat-insulating body 30, i. e. in the example used in Figure 5, in a top or main panel 31 and/or a bottom or sub-panel 32 of such an insulating body 30 of a tank 71 designed to receive an extremely cold liquid such as LNG or LPG. Such a tank 71 may be equipped with, for example, a surface tank, a floating barge, or the like. (for example, FSRU - "Floating Storage and Regasification Unit" or FLNG - "Floating Natural Gas Liquefaction Unit") or a vessel such as an LNG tanker transporting this energy liquid between two ports.

[127] The block of foam according to the invention, shown in Figure 6, contains a group of anchor elements 40 distributed over its different surfaces: top 41 and side 42, 43. These anchor elements 40 are placed so as to be flush with the surface of these surfaces 41 , 42, 43 foam blocks without showing the thickness of the foam (or a slight thickness) covering them and/or protecting them from the outside.

[128] Figure 7 shows in cross section an embodiment of such an anchor element 40. This anchor element 40 shows a plate 44 extending along a plane. This plate 44 contains a group of holes 45 which consist of a mechanical anchoring means, in other words one of two elements, allowing the foam block to be fixed in or to the thermal insulation shell of the tank by engagement with an element of the heat-insulating body (not shown in the attached figures). The plate 44 also contains a group of identical anchor pins 46 as well as a central anchor pin 47 showing a larger dimension than the anchor pins 46. The function of these pins 46, 47 is to secure the anchor element 40 in the best possible way in the fiber reinforced foam block of the invention. The anchor pins 46 are ideally arranged in a circle to form a circle close to the circumference or periphery of the anchor element 40.

[129] The anchor element 40 shown in Figure 7 is preferably placed on the conveyor belt 11 with the pins 46, 47 pointing upwards and the plate 44 resting on said belt 11.

[130] However, it will also be possible to provide for the placement of these anchor elements 40 on the upper surface 41 of the block and even on the side surfaces 42, 43, as can be seen in the block presented in Figure 6. In the latter case, it may be advantageous to provide for the insertion of pins 46, 47, at least to a minor extent, into an adjacent/adjacent mat of fibers prior to impregnation with polymeric foam.

[131] Of course, one of these holes 45 of the anchor element 40 can essentially be used to form the female part of the anchor element, but it can also be provided that the anchor element requires the use of a group of holes 45. Moreover, these holes 45 consist of a solution with anchor elements, but the invention is in no way limited to this embodiment, and it will be possible to provide one or more anchor elements 40 of different shapes and different mechanical characteristics.

[132] With reference to Figure 8, a sectional view of the LNG tanker 70 shows a sealed and insulated tank 71 of a prismatic general shape, installed in a double hull 72 of the vessel. The tank wall 71 includes a main pressure barrier designed to be in contact with the LNG contained in the tank, an auxiliary pressure barrier located between the main pressure barrier and the double hull 72 of the vessel, and two isolation barriers located, respectively, between the main pressure barrier and the auxiliary pressure barrier. barrier and between the auxiliary pressure barrier and the double housing 72.

[133] In a known manner, loading and unloading pipes 73 located on the upper deck of the vessel can be connected through suitable connectors to a shipping or port terminal in order to transport a cargo of LNG from tank 71 or to tank 71.

[134] Figure 8 is an example of an offshore terminal including a loading/unloading station 75, a subsea pipeline 76, and an onshore facility 77. The loading/unloading station 75 is a fixed offshore facility including a movable arm 74 and a column 78 that supports the movable arm 74. The movable arm 74 holds a bundle of insulated flexible hoses 79 that can be connected to the loading and unloading pipes 73. The rotatable movable arm 74 fits all sizes of LNG tankers. A connecting pipeline (not shown) extends inside the column 78. The loading and unloading station 75 allows loading and unloading of the LNG tanker 70 from the land installation 77 or to the land installation 77. This installation contains tanks 80 for storing liquefied gas and connecting pipelines 81 connected by subsea pipeline 76 with a loading and unloading station 75. Subsea pipeline 76 allows transporting liquefied gas between the loading and unloading station 75 and land installation 77 over a long distance, for example, 5 km, which allows you to keep the LNG tanker 70 at a great distance from the coast during loading - unloading operations.

[135] To create the pressure required for transporting liquefied gas, the onboard pumps in the vessel 70 and/or the pumps equipped with the surface unit 77 and/or the pumps equipped with the loading and unloading station 75 are used.

[136] As stated above, the use or application of the object of the present invention, i.e., in this case, the fiber-reinforced polyurethane/polyisocyanurate foam block 20, is not intended to be limited to a tank built into the supporting structure, but it is also provided for tanks of type A, B and C of the IGC Code in effect as of the filing date of this patent application, and for future versions of this code, unless very significant changes apply to these tank types A, B and C, and it is also clear that other types of tanks may, while allowing for a change in the IGC code, become applications that may be envisaged for the block 20 of fiber-reinforced PUR/PIR foam according to the present invention.

[137] The following presents a portion of the experiments and tests performed by the applicant company to enable it to evaluate the subject matter and its scope of protection, while it is assumed that other tests / experiments were performed and they can be submitted subsequently if necessary / if required.

[138] A polyurethane foam composition containing fibers in the form of mats is used to demonstrate the invention, and these fibers are always presented in the form from long to continuous; more precisely, the lengths of these fibers are exactly the same as in the compositions according to the invention and compositions according to the prior art. In particular, Applicant has tested the subject matter with fibers considered to be short (as opposed to the definition given above for long-continuous fibers) or presented in the form of a fabric, and the results obtained are equivalent or substantially similar to those obtained with a mat of long-continuous fibers. , as shown below.

[139] Thus, in order to make sure that only the combination of specific fiber density characteristics of the fiber reinforcements with the choice of PIR foam exhibits a particularly specific foam start time, or one suitable for the characteristics of said fiber reinforcements, no other PIR block preparation parameter foam does not change or differ between preparations in accordance with the invention and preparations in accordance with the prior art. As non-exhaustive examples, the fact that the nucleation, the amounts of blowing agents, the reaction temperatures, the nature and amounts of the mixture of chemical components, the pouring process, the distance between the pouring of the mixture of chemical components and the DBL or free expansion device, if appropriate, are strictly identical in cases according to the invention and cases according to the prior art.

[140] Of course, in this example, it has been chosen to illustrate the invention with PUR foam for clarity and brevity, but equivalent or substantially similar results have been obtained with PIR foams as well as PUR/PIR blends.

[141] Also, the preparations of the fiber-reinforced foam, the results of which are presented below, use the free expansion technology, but the applicant company has shown that equivalent or practically similar results were obtained by DBL in terms of fiber-reinforced foams according to the invention and fiber-reinforced foams according to the state of the art. technology.

[142] Moreover, it is understood that all compositions tested in the sequel are considered under identical density conditions, and it is understood that this density parameter is involved in the evaluation of compressive strength performance.

[143] For compositions according to the prior art, the characteristics of fibrous reinforcements and PUR foam are as follows:

[144] [Table 1]

type of product Content
(relative share of different components) Description Commercial link to the product Polyol 1
(mixture of polyol ether based on glycerin and sorbitol) 60-75 385-415 mg KOH/g Mixture of polyols based on glycerol and sorbitol type Daltolac ^® R200, R251, R404, R470, R500 Polyol 2
(blend of polyether and aromatic polyesterdiol) 25-40 230-250 mg KOH/g Aromatic polyester polyol type
Stepanpol ^® PS-1752, PS-2352, PS-3152 and alkyl ether type polyether polyol: PEG, PPG, pBDO, pHDO, pTMEG, Pluriol Isocyanate 95-135 30-31.5% NCO Polymeric diphenylmethane diisocyanate type Suprasec ^® S5005 Water
(chemical blowing agent) 0.05-1.5 Physical Blowing Agent 3-12 365mfc/227ea or 245fa or 123zd Surface-active substance 0.5-1.5 Silicone with grafted PEO/PPO ^Tegostab® B8404 or B8465 Tin based reaction catalyst 0.05-0.08 DBTL ^Dabco® T12N glass mat 22 Continuous fiber glass mat UnifiloU809 or CFM1020

[145] For compositions according to the invention, the characteristics of fibrous reinforcements and PUR foams are as follows:

[146] [Table 2]

type of product Content
(relative share of different components) Description Commercial link to the product Polyol 1
(mixture of polyol ether based on glycerin and sorbitol) 60-75 385-415 mg KOH/g Mixture of polyols based on glycerol and sorbitol type Daltolac ^® R200, R251, R404, R470, R500 Polyol 2
(blend of polyether and aromatic polyesterdiol) 25-40 230-250 mg KOH/g Aromatic polyester polyol type
Stepanpol ^® PS-1752, PS-2352, PS-3152 and alkyl ether type polyether polyol: PEG, PPG, pBDO, pHDO, pTMEG, Pluriol Isocyanate 95-135 30-31.5% NCO Polymeric diphenylmethane diisocyanate type Suprasec ^® S5005 Water
(chemical blowing agent) 0.05-1.5 Physical Blowing Agent 3-12 365mfc/227ea or 245fa or 123zd Surface-active substance 0.5-1.5 Silicone with grafted PEO/PPO ^Tegostab® B8404 or B8465 Tin based reaction catalyst 0.05-0.08 DBTL ^Dabco® T12N glass mat 22 Continuous fiber glass mats with different densities in tex or different binder content CFM 1020 or CFM 1050 or Uniconform or Unifilo U809, U801, U812, U813, U816, U850, U852, U854

[147] Note that the foam onset times for the PUR foams used and those presented above are logically the same for the compositions according to the prior art and according to the invention, since the foam used is identical, regardless of the case under consideration.

[148] After testing, some of the results are presented below in a simplified manner in order to illustrate the findings of the applicant company in the case where the fibrous reinforcements are in the form of at least one mat of glass fibers.

[149] [Table 3]

Mixture of chemical components and blowing agents (identical density, essentially equal to 130 kg/m ³ , tested compositions) with fibers of the type indicated above Fiber content, %
and characteristics of the distribution of fibers in the foam
(taking the core according to the height/thickness of the block) Tensile performance according to ISO 1926
(stretching in the plane of the mat(s) Thermal contraction coefficient according to the standard
ASTM E 228 between +23 and -196°C 8 layers of U809 or U801 for a block with a thickness of 180mm
Approximately 135 kg/ ^m3 14.4%
Uniform E = 192 MPa α = 17 x 10 ^-6 m/(m K) 12 layers of U812 or U816 or U822 for a block with a thickness of 180mm
Approximately 137 kg/ ^m3 21.6%
Uniform
The presence of air bubbles in the foam E = 253 MPa α = 13 x 10 ^-6 m/(m K) 15 layers of U852 or U854 or U850 for a block with a thickness of 180 mm
Approximately 134 kg/ ^m3 26.9%
Uniform
The presence of air bubbles in the foam E = 301 MPa α = 11.0 x 10 ^-6 m/(m K) For a block with a thickness of 180 mm:
1 layer U850
2 layers U809
1 layer U812
1 layer U850
1 layer U812
2 layers U809
1 layer U850
(in accordance with the invention)
Approximately 135 kg/ ^m3 23%
10%
15%
23%
15%
9%
22%
Presence of air bubbles E = 255 MPa
E = 155 MPa
E = 180 MPa
E = 260 MPa
E = 180 MPa
E = 152 MPa
E = 245 MPa α = 12 x 10 ^-6 m/(m K)
α = 20 x 10 ^-6 m/(m K)
α = 18 x 10 ^-6 m/(m K)
α = 12 x 10 ^-6 m/(m K)
α = 18 x 10 ^-6 m/(m K)
α = 20 x 10 ^-6 m/(m K)
α = 13 x 10 ^-6 m/(m K)

It should be noted that the first composition (with 8 layers of U809 or U801 for a block with a thickness of 180 mm) from table 3 above consists of a composition in accordance with document FR2882756. The results for such a composition according to document FR2882756 are very much inferior to the results obtained with the composition according to the present invention (last composition in table 3).

[150] As can be seen from the results presented in the table above, in relation to the three criteria considered when comparing the resulting fiber-reinforced foams, the foams in accordance with the invention show results that are significantly better than the results of the fiber-reinforced foams according to the prior art.

[151] Moreover, it should be noted that the fiber-reinforced PUR/PIR foams of the invention do not show any significant deterioration in their (very low) thermal conductivity properties.

[152] [Table 4]

Thermal conductivity (mW/(m K) at -160°C at -120°C at +20°C 10-14 11-16 23-27

[153] Although the invention has been described in connection with several specific embodiments, it is clear that it is not limited to them in any way and that it contains all technical equivalents of the described means, as well as combinations thereof, if they are within the scope of protection. inventions.

[154] The use of the verbs "comprise" or "include" and their conjugate forms does not preclude the presence of other elements or steps other than those set forth in the claims.

[155] In the claims, any reference numeral in parentheses should not be interpreted as limiting the claim.

Claims (28)

1. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam of the heat-insulating body (30) of a sealed and heat-insulated tank, while the density of the block (20) of fiber-reinforced foam is from 30 to 300 kg/m ³ , block (20) of fiber-reinforced polyurethane /polyisocyanurate foam shows an average density of fibers T _f from 1 to 60% by weight of the fibers (10) and shows a width L from 10 to 500 cm, and a thickness E from the lower surface of the specified block (20) to its upper surface from 10 to 100 cm , wherein the block (20) of fiber-reinforced polyurethane/polyisocyanurate foam consists of gas storage cells, characterized in that: - the foam block (20) contains, in its thickness E, two peripheral zones (21, 22), one of which is considered the upper (21), continuing from the upper surface of the block (20), and the other is considered the lower (22), continuing from the lower surface block (20), while each of these two zones (21, 22) represents no more than 20% of the thickness E of the block (20), and they are separated by a zone that is considered intermediate (23); And - peripheral zones (21, 22), upper (21) and lower (22), respectively, show the density of the fibers T _{f top.} and T _{f lower.} so that: 2/3 ≤ (T _{f top} /T _{f bottom} ) ≤ 3/2; And - fiber density T _{f prom.} the intermediate zone (23) is less than the densities of the peripheral zones (21, 22), i.e.: T _{f prom.} < T _{f upper} and T _{f prom} < T _{f lower} . 2. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to claim 1, characterized in that each of the two said peripheral zones (21, 22) represent no more than 10% of the thickness E of block (20). 3. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to claim 1, characterized in that the intermediate zone (23) contains a central zone (26) surrounded by two middle zones (24, 25) representing no more than 20% in thickness E, preferably not more than 10% in thickness E, while the density of the fibers T _{f center.} this central zone (26) is at least one and a half times higher than the fiber density T _{f media.} middle zones (24, 25), i.e. T _{f center.} ≥ 1.5Tf _avg. . 4. Block (20) fiber-reinforced polyurethane/polyisocyanurate foam according to claim 3, characterized in that the fiber density T _{f center.} this central zone (26) is determined relative to the fiber density T _{f top.} and T _{f lower.} peripheral zones (21, 22), upper (21) and lower (22), so that 0.5 ≤ T _{f center.} /(T _{f low} or T _{f high} ) ≤ 2. 5. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to one of the preceding claims, characterized in that the density of the block (20) of fiber-reinforced foam is from 50 to 250 kg/m ³ , preferably from 90 to 210 kg/m ³ . 6. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to any of the preceding claims, characterized in that at least 60%, preferably at least 80% of the above gas storage cells, preferably having a low thermal conductivity, exhibit a shape that is elongated or extended along an axis parallel to the thickness axis E of the block (20) of the fiber-reinforced polyurethane/polyisocyanurate foam. 7. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to any one of the preceding claims, characterized in that the fibers consist of glass fibers or basalt fibers, preferably glass fibers. 8. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to any one of the preceding claims, characterized in that the fibers are long to continuous fibers. 9. Block (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to any one of the preceding claims, characterized in that the average fiber density T _f is from 2 to 25%, preferably from 6 to 20%. 10. Block (20) fiber-reinforced polyurethane/polyisocyanurate foam according to any one of the previous paragraphs, characterized in that the bottom surface and/or top surface (41), preferably the top surface (41), of the specified block shows (demonstrate) anchor elements (40 ) capable of engaging with the means of engagement of the heat-insulating body (30) in order to anchor the foam block to said body (30), preferably said anchor elements (40) being made of a material different from the material of the foam or the material of the fibers. 11. Sealed and thermally insulated tank (71), consisting of: - a tank built into a supporting structure containing a sealed and heat-insulated tank containing at least one sealed metal membrane, consisting of a group of metal ribs or metal plates that may contain corrugations, and a heat-insulating housing (30) containing at least one heat-insulating a barrier adjacent to said membrane, or - tank type A, B or C as defined in the IGC code, containing at least one thermal insulation shell (30), characterized in that the heat-insulating body (30) comprises a group of blocks (20) of fiber-reinforced polyurethane/polyisocyanurate foam according to any one of the preceding claims. 12. Vessel (70) for transporting a cold liquid product, including at least one body (72) and one sealed and insulated tank (71) according to claim 11, located in the body or installed on the specified vessel (70), when the specified tank (71) is type A, B or C as defined in the IGC code. 13. A system for transporting a cold liquid product, including a vessel (70) according to the previous paragraph, insulated pipes (73, 76, 79, 81) located so as to connect a tank (71) installed in the hull of the vessel with a floating or shore installation ( 77) for storage, and a pump for driving the flow of cold liquid product through insulated pipes from the floating or onshore storage facility to the ship (70) or to the floating or onshore storage facility from the ship (70). 14. The method of loading or unloading a ship (70) according to claim 12, in which the cold liquid product is transported through insulated pipes (73, 76, 79, 81) from a floating or onshore installation (77) for storage to a ship (70) or to floating or shore installation (77) for storage from a ship (70). 15. A method of preparing a block (20) fiber-reinforced polyurethane/polyisocyanurate foam heat-insulating body sealed and insulated tank according to any one of paragraphs. 1-10, characterized in that it includes the steps in which: a) mixing (12) chemical components necessary to obtain a polyurethane/polyisocyanurate foam containing reagents for the production of polyurethane/polyisocyanurate, optionally at least one reaction catalyst, optionally at least one emulsifier and at least one blowing agent, b) impregnating with the help of the gravity flow of the above mixture (12) of chemical components a group of fibrous reinforcements (10) arranged in superimposed layers and showing variable fiber densities, the fibrous reinforcements (10) continuing essentially in a direction perpendicular to the direction of the specified gravity flow, c) form and expand fibre-reinforced polyurethane/polyisocyanurate foam, the expansion of fiber-reinforced polyurethane/polyisocyanurate foam is considered to be free expansion, i. without the restriction imposed by the volume of a closed section on at least one surface, or wherein the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam is physically constrained by the walls of the two-belt laminator, physically constrained by the walls of the two-belt laminator forming a rectangular tunnel with a side-to-side wall spacing of L and a horizontal wall spacing of E, such surrounding the expanding fiber-reinforced foam so as to obtain the aforementioned fiber-reinforced polyurethane/polyisocyanurate foam block (20). 16. Method for preparing a block (20) of a fiber-reinforced polyurethane/polyisocyanurate foam according to claim 15, characterized in that in the case where the expansion of step c) is performed by free expansion, at least one of the peripheral zones (21, 22) is preferably the upper zone (21) is formed independently and secured as soon as a cut has been made on at least the free expansion surface to form said foam block (20).

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