CN113631611A

CN113631611A - Polyurethane/polyisocyanurate foam blocks for insulated bodies of tanks and method for their preparation

Info

Publication number: CN113631611A
Application number: CN202080024116.2A
Authority: CN
Inventors: 纪尧姆·德康巴利尤; 布鲁诺·德莱特; 弗洛里安·克鲁普
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2019-03-26
Filing date: 2020-03-16
Publication date: 2021-11-09
Anticipated expiration: 2040-03-16
Also published as: EP3947504A1; KR20210146953A; CN113631611B; FR3094451B1; WO2020193874A1; JP2022528619A; SG11202110316VA; FR3094451A1

Abstract

The invention relates to a fibrous polyurethane/polyisocyanurate foam block wherein the density of the fibers increases along the thickness of the block from a lower density range of 1% to 9.99% by weight of the fibers (10) to an upper density range of 10% to 35% by weight of the fibers (10) from the bottom to the top thereof.

Description

Polyurethane/polyisocyanurate foam blocks for insulated bodies of tanks and method for their preparation

Technical Field

The subject of the present invention is a fiber-reinforced Polyurethane (PUR) and/or Polyisocyanurate (PIR) foam block assembled in an insulating body, which must exhibit very specific mechanical and thermal properties, while being able to be produced as economically as possible, in view of their specific application. The foam blocks are used in tanks integrated in membrane structures (also called integrated tanks) or in self-supporting/semi-supporting tanks of type a, B or C, for containing extremely cold fluids (called cryogenic fluids), such as in particular liquefied natural gas (LNG, abbreviated in french to GNL) or liquefied petroleum gas (LPG, abbreviated in french to GPL).

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

More particularly, the invention finally relates to a sealed and thermally insulated tank using such a foam, a vessel equipped with at least one such tank, a method of loading/unloading such a vessel and a transfer system for liquid products contained in such a vessel.

Background

Polyurethane PUR foam is a porous insulating material, consisting of fine cells, storing gas with low thermal conductivity. PUP foams are used in a large number of applications, such as in the automotive industry in the form of flexible PUR foams or in the form of rigid PUR foams for thermal insulation. The formation of polyurethane-type foams is well known to those skilled in the art. Its formation involves a multi-component 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 expansion agent (also denoted by the term "blowing agent"). The condensation reaction is catalyzed in particular by basic and/or nucleophilic compounds, such as tertiary amines or metal-carboxylate complexes, for example tin or bismuth salts. The polyols conventionally used for the production of PUR foams are polyether polyols or polyester polyols. Thus, a large amount of compound is required to form the PUR foam.

Polyisocyanurate (PIR) and polyurethane/polyisocyanurate (PUR-PIR) foams are also used in the construction industry (construction/renovation) and show the advantage of providing better fire performance and greater compressive strength than PUR. The process for forming these foams is similar to the process for forming PUR foams. This is because PUR, PIR and PUR-PIR foams are obtained depending on the isocyanate/polyol ratio.

PUR, PIR and PUR-PIR foams are known to the person skilled in the art. However, the addition of fibres poses specific technical problems, such as the need for a good impregnation of the fibres, so that currently no foams exist which at least locally exhibit a relatively high content of fibres.

Indeed, in the technical field specific to the use of such foams in tank insulating bodies, the face of the body exposed to the internal space of the tank is subjected to very low temperatures, for example about-160 ℃ in the case of LNG, while the external space of the tank (usually the hull of a ship) often exhibits a higher ambient temperature, at least equal to, indeed even much higher than the ambient temperature of the considered ambient air or sea temperature (around 20 ℃).

Thus, when used in such tank insulation bodies, PUR, PIR and PUR-PIR foam blocks will experience a very significant temperature gradient along their thickness during loading with extremely cold fluid (referred to as cryogenic fluid), which causes a phenomenon of uneven shrinkage of the foam block. This uneven shrinkage of the foam block causes a bimetallic effect, which results in a tendency for the block to sag (sag) along its longitudinal axis due to uneven shrinkage of the block along its thickness, while the two ends rise significantly. Since the foam blocks are usually fixed mechanically or by adhesive bonding, this sagging severely reduces the available mechanical properties of the PUR, PIR and PUR-PIR foam blocks, indeed even locally reduces the thermal properties of the insulating body (integrating the foam block according to the invention).

In recent years, this phenomenon of bimetallic effect or sagging of the foam blocks has been exacerbated by the fact that the thickness of the foam blocks forming the insulating material has increased, sometimes very significantly for such tanks containing cryogenic liquids. In particular, when these tanks comprise a double layer of insulating material, generally denoted as "primary" and "secondary" layers, which are the furthest away from the cryogenic liquid, the thickness E of the secondary insulating material has increased very significantly in recent constructions (for example of the MARK type). Thus, the thickness E of the secondary thermal insulation layer changes from 170mm (millimeters) in the Mark III Structure to 300mm in the Mark III Flex Structure, and 380mm in the Mark III Flex + Structure.

When the thickness of the secondary insulation layer is significantly increased relative to the thickness of the primary insulation layer, the bimetallic effect or sagging of this secondary layer can have particularly detrimental structural consequences for the insulation body of the sealed insulation tank.

Structures of structures such as those described in documents FR 2882756, WO2017/202667 and JP 2005225945 are known, but none of these documents provides a satisfactory solution to the specific technical problem set forth above.

Currently, there are no fiber-reinforced or non-fiber-reinforced polyurethane and/or polyisocyanurate foam blocks that can respond effectively to this problem, in other words, there are no PUR, PIR and PUR-PIR foam blocks that exhibit thermo-mechanical stability between an initial state (in a homogeneous thermal environment) and their working state (i.e. when it is in a tank containing a cryogenic liquid).

In order to overcome the problem of deformation or geometric instability between these two states of the foam block, specially shaped foam blocks (in particular integrated with recesses) or foam blocks of reduced dimensions are currently produced in order to limit the thermal deformation of each (small) volume element or (small) foam block within acceptable limits. The production of these small foam blocks requires a large number of operations for cutting, positioning and connecting them to each other, which represents a large cost. Furthermore, the presence of many expansion joints reduces the thermal performance quality of the tank very significantly.

Disclosure of Invention

Against this background, the applicant company has succeeded in developing a process for producing Polyurethane (PUR) and/or Polyisocyanurate (PIR) foams containing a significant amount of fibers, which produces fiber-reinforced foams capable of maintaining their mechanical properties as well as their shape/structure throughout the foam block when the block is in the conditions of use, i.e. in a very different thermal environment between its two faces (top or bottom), while exhibiting excellent mechanical and thermal properties.

The present invention therefore aims to overcome the drawbacks of the prior art by providing a particularly effective solution for industrially obtaining fiber-reinforced PUR/PIR foams, possibly of (very) large size, the mechanical/thermal properties of which 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 state of use (in the state of use, in which the foam block is in a very heterogeneous thermal environment, the temperature difference between their top face and their bottom face being at least equal to 80 ℃, indeed even at least equal to 100 ℃, considered along the thickness E of the block).

After various studies and analyses, the applicant company has found that the preparation of fiber-reinforced Polyurethane (PUR) and/or Polyisocyanurate (PIR) foam blocks and for their manufacturing/design purposes, is capable of solving the technical problems associated with the very significant changes in their thermal environment during the use of PUR/PIR foam blocks.

Advantageously, according to a preferred embodiment, the production costs of such fiber-reinforced foams can also be reduced very significantly by reducing the material loss of the foam block very significantly (cutting of the foam block is usually required in the prior art).

The invention therefore relates to a fiber-reinforced polyurethane/polyisocyanurate foam block for sealing the insulating body of an insulating tank, the fiber-reinforced foam block having a density of 30kg/m³To 300kg/m³The fiber-reinforced polyurethane/polyisocyanurate foam blocks have an average fiber density T of between 1% and 60%, preferably between 2% and 30% by weight, based on the weight of the fibers_fAnd having a width L of at least 10 cm, advantageously between 10 cm and 500 cm, and a thickness E of at least 10 cm, advantageously between 10 cm and 100 cm, from the top face to the bottom face of the block, the fiber-reinforced polyurethane/polyisocyanurate foam block consisting of cells storing a gas, advantageously having a low thermal conductivity.

At least 95% by weight of the fiber-reinforced polyurethane/polyisocyanurate foam blocks are composed of cells, polyurethane/polyisocyanurate foams and fibers which store gases which advantageously have a low thermal conductivity.

The foam blocks according to the invention consist (only) of Polyurethane (PUR) and/or Polyisocyanurate (PIR) foam, fibers, preferably fibers of a single nature, such as glass fibers, and gas-trapping cells and optionally very small amounts of, for example, fillers or other functional auxiliary material parts, i.e. wherein for fillers or other functional auxiliary materials a maximum of 5 wt.%, indeed even preferably a maximum of 2 wt.% or 1 wt.%, of the foam block according to the invention (for fiber-reinforced polyurethane/polyisocyanurate foam blocks at least 98 wt.% or 99 wt.% of the block consists of gas-storing cells, polyurethane/polyisocyanurate foam and fibers). This is because the foam bun according to the invention is obtained in the following manner:

preferably in a Double Belt Laminator (DBL) in a single operation of preparing the foam (mixing the reactive ingredients, optional fillers/adjuvants and fibres);

in the above operation, the block is usually already free to expand on its top surface, assisted by the cutting operation.

The foam is characterized by a fiber density that increases along a thickness E from a lower density range of 1% to 9.99% by weight of the fibers to an upper density range of 10% to 35% by weight of the fibers from a bottom surface to a top surface of the mass.

The present invention is intended to be particularly, but not exclusively, applicable to the case where the foam blocks are mounted at a secondary layer (often referred to as a "secondary layer"). In the present application, preferably the foam bun has a thickness of at least twenty-five (25) centimeters (cm), and indeed even more preferably at least 30cm or 35 cm.

The expressions "lower limit range" and "upper limit range" are understood to mean two identical parts of a fiber-reinforced foam block, i.e. the foam is cut along a median plane of said block, which passes through the middle of the block (or the height of the block when positioned in the insulating body) along the thickness E.

The terms "upper/top" and "lower/bottom" are understood to refer to the circumstances or directions imparted to the foam bun once it is in place in the insulating body of the can. Thus, when the insulating body is positioned in the tank, the upper part or top surface of the foam block is located near or on the container side of the tank, while the lower part or bottom surface of the foam block is located towards or on the outer side of the tank, i.e. in case the tank is integrated or mounted in a vessel for transport and/or storage of cryogenic liquid, in particular towards the hull of the vessel.

It is understood that these concepts or terms have no meaning during the manufacture or preparation of the foam block, since the foam block is not yet installed in the insulating body of the tank. In other words, the position of the foam block obtained at the outlet of the preparation/manufacturing line for preparing foam blocks according to the invention is entirely possible as opposed to the final insertion/assembly position in the insulating body of the tank.

The expression "cells storing a gas" is understood to mean the following facts: polyurethane/polyisocyanurate foams have closed cells that encapsulate gas, exhibit low thermal conductivity, originate from gas injected during the nucleation stage of the reaction mixture, or originate directly or indirectly from chemical or physical expanding agents.

The term "fiber" or the expression "fiber reinforcement" is understood to mean the fact that the fiber can be provided in two different forms:

the fibers are provided in the form of at least one fiber fabric, wherein the fibers are perfectly aligned in at least one direction, in other words, the fibers have at least one advantageous fiber direction. The expression "fibre fabric" refers per se to a well-defined technical definition known to the person skilled in the art,

Alternatively, the fibres are provided in the form of at least one fibre mat, wherein the fibres do not have a well-defined orientation, in other words, the fibres are oriented substantially isotropically along the main plane of the mat layer. Likewise, the expression "fiber mat" refers per se to a well-defined technical definition known to the person skilled in the art.

According to one embodiment, the expression "(advantageously) gas having a low thermal conductivity" is understood to mean a gas originating from a blowing agent; when the blowing agent is a "chemical blowing agent", it is generated by a chemical reaction of the blowing agent, and when the chemical blowing agent consists of water, it is usually carbon dioxide (CO)₂) (ii) a Or from physical blowing agents, e.g. nitrogen molecules (N)₂) Oxygen molecule (O)₂) Carbon dioxide, hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, and mixtures thereof and the corresponding alkyl ethers. Physical blowing agents, such as nitrogen molecules N₂Oxygen molecule O₂Or CO₂In gaseous form. These gases are dispersed or dissolved in the liquid substance of the copolymer, for example, under high pressure when a static mixer is used. By depressurizing the system, nucleation and growth of bubbles will create a porous structure.

The expression "average density of fibres T _f"is understood to mean the density of the fibers expressed by weight of the fibers relative to the total weight of the fiber-reinforced foam bun, without regard to the variable local percentage of these fibers (within the bun).

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

Finally, the thermal properties of the fiber reinforced foam bun are at least the same as the thermal properties of the prior art non-fiber reinforced foam bun; more precisely, the foam block has a thermal conductivity along the thickness E of less than 30mW/m.k (milliwatts per meter per kelvin), i.e. 0.03W/m.k, preferably less than 25mW/m.k, more preferably less than 23mW/m.k, measured at 20 ℃, and the foam block has a thermal conductivity of 20mW/m.k at the use condition, i.e. its being located inside a tank containing LNG, the top face of the block being at-160 ℃.

Other advantageous features of the invention are briefly described below.

Preferably, the density of the fiber-reinforced foam blocks is in the range of 50kg/m ³To 250kg/m³Preferably between 90kg/m³And 210kg/m³In the meantime. It should be noted here that for foam blocks used in tanks of the self-supporting type (B-type, C-type) or semi-supporting type (a-type), the density of the fibre-reinforced foam block is preferably in the range of 30kg/m³To 90kg/m³And in the case of a film, the preferred density range is 90kg/m³To 210kg/m³In the meantime.

Advantageously, the increase in the density of the fibers corresponds to an increasing gradient of between 0.05% and 1.5% by weight of the fibers per cm, preferably between 0.2% and 1.2% by weight of the fibers per cm, with respect to the total weight of the fiber-reinforced polyurethane/polyisocyanurate foam. These density values are understood to mean the average value of the entire mass.

Advantageously, at least 60%, preferably at least 80%, of the above-mentioned cells storing the gas, which advantageously has a low thermal conductivity, have an elongated or elongated shape along an axis parallel to the axis of the thickness E of the fiber-reinforced polyurethane/polyisocyanurate foam block.

Preferably, the fibers consist of glass fibers or sisal fibers, preferably glass fibers.

Preferably, the fibers are long to continuous fibers.

The expression "the fibers are long to continuous" (or "long to continuous fibers") is understood to mean the following fact: the fibers, or if appropriate, the conglomerates of fibers (fibers bonded or fixed to each other) of the fiber assembly, all or at least 90% of the fibers (whether individual or aggregated, forming the equivalent of a single fiber) by total mass of the fibers, have a length of at least five (5) centimeters (cm).

Preferably, the average density T of the fibers_fBetween 2% and 25%, preferably between 4% and 15%.

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

It is clearly understood here that a foam block having such a parallelepiped or cube shape may have one or more local protrusions, for example in the form of anchors as given below, or conversely, empty or hollow portions, while still being able to be described as parallelepiped or cube shape.

According to a preferred embodiment of the invention, the lower limit of the fiber density ranges from 2% to 6% by weight of the fibers, and the upper limit of the fiber density ranges from 12% to 25% by weight of the fibers.

Advantageously, the bottom and/or top, preferably top, face of the block has an anchor engageable with engagement means (not shown in the drawings) of the insulating body to secure or anchor the foam block to the body, preferably the anchor being made of a material different from foam or fibres.

These anchors are advantageously metal elements (these anchors can also be made of plastic/polymer or composite material of one or more polymers in combination with ceramic and/or metal material), for example with L-shaped attachment lugs, to engage with an element or a portion of the insulating body that encloses or houses the fibre-reinforced foam blocks. This part of the insulating body can consist of a metal film for sealing the container, for example made of stainless steel, or based on manganese (in the case of a membrane tank), or, in the case of a self-supporting or semi-supporting tank of type a, B or C, of a vapour barrier (with the technical function of ensuring sealing against the surrounding environment outside the tank). In one possibility provided by the invention, this element or this part of the insulation body (in the membrane tank) has a notch or the like intended to allow engagement with the part of the anchor for mechanical maintenance or retention of the fiber-reinforced foam block with the other insulation block element. Of course, these anchors may also have the function of anchoring the foam blocks to the hull (in the case of membrane tanks) or to the self-supporting structure (in the case of self-supporting tanks of type a, B or C), it being understood that these anchors are those present on the bottom surface of the foam blocks.

In the context of the present invention, these anchors are at least partially inserted into the fiber-reinforced body, i.e. those constituting the lower or upper layer of the fiber-reinforced stack, in order to make it possible to position them on the face of the foam bun after it has been prepared/completed, but without protruding from said face.

Advantageously, in the context of the present invention, these anchors are only present on the top surface of the fiber-reinforced foam block (because of the high fiber density), so that the anchors are firmly attached to the fiber-reinforced foam block.

Advantageously, the fiber-reinforced foam block according to the invention comprises a flame retardant in a proportion of 0.1% and 5% by weight, of the organophosphorus type, 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 a mixture thereof; or of the inorganic flame-retardant type, advantageously red phosphorus, expandable graphite, hydrated aluminum oxide, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulfate, or cyanuric acid derivatives, or mixtures thereof.

The invention also relates to a sealed and thermally insulated tank integrated in a supporting structure, said tank comprising:

Tank integrated in a supporting structure, comprising a sealed insulating tank comprising at least one sealed metal film consisting of a plurality of metal strakes or plates, which can comprise corrugations, and an insulating body comprising at least one insulating barrier adjacent to said film, or

Storage tank of type a, B or C as defined by IGC regulations, comprising at least one insulating body.

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

The expression "IGC regulations" is understood to mean "international bulk transport liquefied gas vessel construction and equipment regulations", as referred to the type B and type C tanks, well known to the person skilled in the art.

It should be noted that, in particular in the IGC regulations, the term "membrane tank" may be used instead of the term "integrated tank" to denote one and the same type of tank, in particular provided in a tanker for transporting and/or storing at least partially liquefied gas. The "membrane tank" is integrated in the support structure, whereas the a-, B-or C-type tanks are considered to be self-supporting, or semi-supporting (in particular a-type).

The tank comprises a plurality of fiber-reinforced polyurethane/polyisocyanurate foam blocks directly obtained by the above-described production process.

Finally, the invention also relates to a vessel for transporting cold liquid products, comprising at least one hull and a sealed and insulated tank as briefly described above, positioned in the hull or mounted on said vessel when said tank is a tank of type a, B or C according to the definition given by the IGC regulations.

Advantageously, in the case where the tank consists of a tank integrated in a supporting structure (membrane tank), such a ship comprises at least one sealed and insulated tank as described above, said tank comprising two successive sealing barriers, one primary sealing barrier in contact with the product contained in the tank, and another secondary sealing barrier, located between the primary barrier and the supporting structure, preferably formed by at least a portion of the wall of the ship, these two sealing barriers alternating with two insulating barriers or a single insulating barrier, located between the primary barrier and the supporting structure.

According to the International Maritime Organization (IMO) regulations, such tanks are commonly referred to as integrated tanks, e.g. NO-type tanks, including NO

NO

NO

Or NO 96

Or MARK

MARK

Tanks of the Flex or Flex + type, preferably NO type.

Preferably, the tank is called membrane type or type a, B or C, containing Liquefied Natural Gas (LNG) or Liquefied Gas (LG).

The invention also relates to a transport system for a cold liquid product, comprising a vessel as described above; an insulated pipeline arranged to connect a tank mounted in the hull of a vessel to a floating or onshore storage unit; and a pump for driving a flow of the cold liquid product from the floating or onshore storage unit to the vessel or from the vessel to the floating or onshore storage unit through the insulated conduit.

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

The invention also relates to a process for the preparation of a fiber-reinforced polyurethane/polyisocyanurate foam block for the insulation body of a sealed insulation tank as briefly described above, said process being characterized in that it comprises the following stages:

a) mixing the chemical components required for obtaining a polyurethane/polyisocyanurate foam, optionally at least one reaction catalyst, optionally at least one emulsifier and at least one blowing agent, wherein the components comprise the reactants for obtaining a polyurethane/polyisocyanurate,

b) Impregnating a plurality of fiber reinforcements positioned in a stack and having a variable fiber density by gravity flow of a mixture of chemical components, the fiber density of the top reinforcing layer being at least equal to the fiber density of the bottom reinforcing layer, wherein the fiber reinforcements extend substantially in a direction perpendicular to the direction of gravity flow,

c) a fiber-reinforced polyurethane/polyisocyanurate foam is formed and expanded,

wherein the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam is free, i.e. not limited by the closed cross-sectional volume, or

Wherein the expansion of the fiber reinforced polyurethane/polyisocyanurate foam is physically confined to the walls of the two-belt laminator, preferably physically confined to the rectangular cross-section tunnel formed by the walls of the two-belt laminator, thereby encapsulating the expanded fiber reinforced foam to obtain the above fiber reinforced polyurethane/polyisocyanurate foam block, wherein the distance between the transversely positioned walls of the rectangular cross-section tunnel is L and the distance between the horizontally positioned walls is E.

The expression "emulsification time" is understood to mean the time required from the mixing of the chemical components (a), the start of the polymerization reaction of the chemical components and the start of the expansion and crosslinking phase (c) of the component mixture (i.e. the formation of a fiber-reinforced PUR/PIR foam). This emulsification time is information well known to those skilled in the art. In other words, the emulsification time is the time that elapses after mixing the chemical components at ambient temperature, under the action of bubble nucleation (cells storing gas) and foam expansion, until the mixture turns white. The emulsification time can be determined by visual observation or by detecting thickness changes reflecting foam formation using an ultrasonic sensor.

The expression "the fibre-reinforcement extends substantially in a direction perpendicular to the direction of gravitational flow of the mixture of chemical components" is understood to mean that these fibre-reinforcements are provided (a), in the impregnation stage (b), in the form of a low-thickness layer extending in a plane perpendicular to the direction of flow of the mixture of components. Thus, as shown in fig. 1, in the longitudinal direction I, there are a plurality of fibre-reinforced bodies of width L located in superposed layers, while the mixture of chemical components is deposited on the fibre-reinforced bodies from a dispenser, thereby allowing/enabling gravity flow of the mixture of chemical components. In other words, the mixture of chemical components, optionally under pressure, leaving the distributor, falls under at least its own weight onto the stack of fibers, thereby impregnating these fibrous reinforcing materials from the upper layer to the lower layer.

Of course, in the case of a block of foam according to the invention prepared by free expansion, the block is subsequently cut at least at the open face, usually the top face, which makes said free expansion possible, in order to finally obtain a block of foam according to the invention, of size and shape (usually parallelepiped).

In the composition according to the invention, the use of a chemical blowing agent may be combined with the use of a physical expanding agent. In this case, the physical expanding agent is preferably mixed in liquid or supercritical form with the foamable (co) polymer composition and then converted into the gas phase in the expansion stage of the PUR/PIR foam.

Chemical and physical blowing agents are well known to those skilled in the art and the appropriate amount of chemical and physical blowing agent is selected by those skilled in the art depending on the PUR/PIR foam desired to be obtained.

The term polyol is understood to mean any carbon-based structure bearing at least two OH groups.

Since the PUR, PIR and PUR-PIR foams are obtained depending on the isocyanate/polyol ratio, a PUR, PIR or PUR-PIR foam will be obtained according to this ratio. When the ratio of polyol component to isocyanate component is:

between 1:1 and 1:1.3, a polyurethane PUR foam is to be obtained,

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

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

Suitable polyisocyanates for forming PUR foams, PIR foams and PUR-PIR foams are known to the person skilled in the art and include, for example, aromatic, aliphatic, cycloaliphatic and araliphatic polyisocyanates, and mixtures thereof, advantageously aromatic polyisocyanates.

Examples of polyisocyanates suitable for use in the scope of the present invention include: aromatic isocyanates such as the 4,4' -, 2,4' -and 2,2' -isomers of diphenylmethane diisocyanate (MDI) and any compounds formed by the polymerization of these isomers, toluene 2, 4-and 2, 6-diisocyanate (TDI), m-and p-phenylene diisocyanates, naphthalene 1, 5-diisocyanate; aliphatic, cycloaliphatic or arylaliphatic isocyanates, such as 1, 6-Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), 4' -dicyclohexylmethane diisocyanate (H12MDI), 1, 4-cyclohexane diisocyanate (CHDI), bis (isocyanatomethyl) cyclohexane (H6XDI, DDI) and tetramethylxylylene diisocyanate (TMXDI). Any mixtures of these diisocyanates may also be used. Advantageously, the polyisocyanate is the 4,4' -, 2,4' -and 2,2' -isomer of diphenylmethane diisocyanate (MDI).

In general, it is known to add, during the formation of a PUR, PIR or PUR-PIR foam, 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, to a mixture comprising a polyol, a polyisocyanate and a blowing agent.

According to a preferred embodiment of the present invention, the location of the tunnel wall of the two-belt laminator (DBL) is advantageously defined such that the restriction of the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam results in that at the exit of the two-belt laminator the volume of the fiber-reinforced polyurethane/polyisocyanurate foam is between 85% and 99%, preferably between 90% and 99%, of the expanded volume of the same fiber-reinforced polyurethane/polyisocyanurate foam without free expansion without restriction by such two-belt laminator walls. In this case, in the foam obtained, the cells have an oval shape and are preferably oriented along an axis E, thus giving the advantageous characteristic of resisting compression along this direction E (measured according to standard ISO 844), as well as the characteristics already described in a plane perpendicular to this axis E. The applicant company has carried out tests and experiments to determine the wide and preferred ranges mentioned above, but for the sake of clarity and brevity it is not described here.

By means of the above-described specific parameterization of the limitation of expansion of the fiber-reinforced PUR/PIR foam in the DBL, on the one hand, a fiber-reinforced PUR/PIR foam is obtained in which at least 60%, usually more than 80%, in fact even more than 90%, of the cells storing the gas with low thermal conductivity extend longitudinally along an axis parallel to the thickness E axis of the foam block; and, in addition to the specific selection regarding the properties of the fiber reinforcement and the viscosity of the mixture of chemical components, contributes to a perfect homogeneity of the fiber-reinforced foam block. These two characteristics (orientation of the cells and the fiber content T in the mass in terms of level and thickness of the mass_fUniformity of the foam) makes it possible to obtain a fiber-reinforced foam block having excellent mechanical properties in the thickness E (compressive strength) and in the plane perpendicular to the thickness direction (tensile strength and low coefficient of thermal shrinkage).

The elongated or elongated shape may be defined by a shape that extends along a length, i.e., it includes a length dimension that is greater than its other dimensions (width and thickness).

According to another embodiment provided by the present invention, the expansion of the fiber-reinforced polyurethane/polyisocyanurate foam is free, i.e. not limited by the closed cross-sectional volume.

In this case, unlike the preparation examples according to the invention using DBLs, fiber-reinforced polyurethane/polyisocyanurate foams are prepared by "free expansion" (as long as the expansion of the fiber-reinforced foam is not constrained on at least one side or at least one face of the expansion) so that, unlike the mold which defines a limited volume, the expansion of the fiber-reinforced foam is free on that side or that face. Normally, free expansion is performed by omitting the (top) cover, while the side walls prevent the foam from overflowing the sides, and the foam naturally expands upwards, possibly beyond the upper ends of these side walls.

Advantageously, after the free expansion phase of the fiber-reinforced polyurethane/polyisocyanurate foam, the fiber-reinforced foam is cut to obtain the above-mentioned fiber-reinforced polyurethane/polyisocyanurate foam blocks.

According to a possibility provided by the invention (not shown in the drawings), a system for applying pressure (which may be, for example, a roller system of the type called "nip roller") is applied to the mixture of components of impregnated fibres and at least of blowing agent, after the impregnation stage of the fibrous reinforcement, which system is intended to apply pressure to the top face of the assembly constituted by the above-mentioned mixture and fibres. The pressure system makes it possible, on the one hand, to smooth the top surface of the module and, by means of the pressure exerted on the module, to help promote impregnation of the fibres in the above-mentioned mixture. The pressure system may consist of a single roller or twin rollers, the relative position of the rollers being adjusted above the liquid composition and possibly below the foam support to provide a perfectly uniform dispersion of the liquid composition. Thus, in doing so, an equal amount of liquid composition is obtained at any point of the cross-section defined by the spacing between the two rollers or between the upper roller and the conveyor belt. In other words, the main purpose of the pressure system is to complement the liquid dispensing device, as it helps to make the thickness/width of the liquid assembly uniform before the main part thereof expands.

Preferably, the above-mentioned mixture of components has a dynamic viscosity η of between 30 and 3000mpa.s, preferably between 50 and 1500 mpa.s.

Advantageously, at least 60% of the above-mentioned 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 the thickness E of the fiber-reinforced polyurethane/polyisocyanurate foam block.

More advantageously, at least 80%, preferably at least 90%, of the above-mentioned 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 the thickness E of the fiber-reinforced polyurethane/polyisocyanurate foam block.

It is clearly understood here that this property relating to the elongated shape of the cells storing the gas which advantageously has a low thermal conductivity and the content/proportion of the cells in the mass according to the invention is particularly relevant in the case of carrying out the production process with DBL, but it is absolutely not limited to this case. This is because this preferred orientation of the cells storing the gas, which advantageously has a low thermal conductivity, is also obtained in the case of free expansion, more particularly when no upper wall/lid restricts the expansion of the fibre-reinforced foam.

Preferably, the fibers (fiber reinforcement) are positioned over the entire width L by stage b) of impregnation of the fibers with the mixture of components and the blowing agent is positioned simultaneously over the entire width L by a controlled liquid dispenser to obtain a fiber-reinforced polyurethane/polyisocyanurate foam.

The term "simultaneously" is understood to mean that the liquid mixture (reactants and at least blowing agent) reaches the fibers simultaneously along the entire width L section, so that impregnation of different fiber reinforcements is initiated or carried out simultaneously or at the same rate along the thickness (or height) of the foam block and also on the same section of the width.

Advantageously, the blowing agent consists of a physical and/or chemical expanding agent, preferably a combination of the two.

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

Under this assumption, as examples of the compound, the following may be cited: 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 selected are those which do not degrade the ozone layer, such as trifluoropropane, 1,1,1, 2-tetrafluoroethane, difluoroethane and heptafluoropropane. Examples of fluoroolefins include 1-chloro-3, 3, 3-trifluoropropene or 1,1,1,4,4, 4-hexafluorobutene (such as HFO FEA1100 sold by DuPont).

According to a preferred embodiment of the invention, the physical expanding agent chosen is 1,1,1,3, 3-pentafluoropropane or HFC-245fa (sold by Honeywell), 1,1,1,3, 3-pentafluorobutane or 365mfc (sold for example by Solvay)

365mfc), 2,3,3, 3-tetrafluoropropan-1-ene, 1,1,1,2,3,3, 3-heptafluoropropane (also known internationally as HFC-227ea, e.g. sold by DuPont), 1,1,1,4,4, 4-hexafluorobutene (e.g. HFO FEA1100, sold by DuPont), trans-1-chloro-3, 3, 3-trifluoropropene (solvent LBA-Honeywell), or mixtures thereof.

Advantageously, the chemical expansion agent consists of water.

Advantageously, in the mixing stage a) of the chemical components, a nucleating gas is incorporated into at least one polyol compound, preferably using a static/dynamic mixer at a pressure of 20 to 250 bar, wherein the nucleating gas represents between 0 and 50% by volume of the polyol, preferably 0.05 to 20% by volume of the polyol.

Preferably, during the mixing stage a) of the chemical components, the temperature of each of the reactants used to obtain the polyurethane/polyisocyanurate is between 10 ℃ and 40 ℃, preferably between 15 ℃ and 30 ℃.

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

According to one possibility provided by the invention, an organophosphorus flame retardant, advantageously triethyl phosphate (TEP), tris (2-chloropropyl) phosphate (TCPP), tris (1, 3-dichloroisopropyl) phosphate (TDCP), tris (2-chloroethyl) phosphate or tris (2, 3-dibromopropyl) phosphate, or a mixture thereof, is additionally added to the mixture in stage a); or an inorganic flame retardant, advantageously red phosphorus, expandable graphite, hydrated aluminum oxide, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulphate or cyanuric acid derivatives, or mixtures thereof.

It is also conceivable to use diethyl ethylphosphonate (DEEP), triethyl phosphate (TEP), dimethyl propylphosphonate (DMPP) or Diphenylphenol Phosphate (DPC) as flame retardant.

When present in the composition according to the invention, the flame retardant is found in an amount of between 0.01% and 25% by weight of the PUR/PIR foam.

Drawings

The following description is given by way of illustration only and not limitation with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing the different stages of the process according to the invention for producing a fiber-reinforced PUR/PIR foam block.

Fig. 2 is a schematic view of an embodiment of a controlled liquid dispenser according to the invention.

Fig. 3 is a schematic view of two sets of insulation panels secured to each other, which form the primary and secondary insulation spaces of a tank, respectively, the panels being formed from a plurality of fiber reinforced polyurethane/polyisocyanurate foam blocks according to the invention.

Fig. 4 is a partial view of a foam block according to the invention, wherein a plurality of anchors have been arranged already during the preparation of the foam block in order to be able to fix or anchor the foam block.

Fig. 5 shows an embodiment of an anchor, visible in a schematic section (cut-away), enabling the insertion of a foam block according to the invention.

Figure 6 is a cut-away schematic view of a tank of an LNG tanker and a loading/unloading terminal for the tank, wherein the tank is fitted with two sets of insulation panels of the type shown in figure 3.

Detailed Description

The preparation of the fiber-reinforced PUR/PIR according to the invention is preferably carried out in the presence of a catalyst capable of promoting the isocyanate/polyol reaction. Such compounds are described, for example, in the prior art document entitled "KunststoffHandBuch, volume 7, polyurethane", published by Carl Hanser in 1993 at 393 th edition, chapter 3.4.1. These compounds include amine-based catalysts or organic compound-based catalysts.

The preparation of the fiber-reinforced PUR/PIR foam cakes according to the invention is preferably carried out in the presence of one or more stabilizers for promoting the formation of a regular cellular structure during the formation of the foam. These compounds are well known to those skilled in the art, and for example, foam stabilizers comprising polysiloxanes such as siloxane-oxyalkylene copolymers and other organopolysiloxanes may be mentioned.

The amount of stabilizer required to be used is known to those skilled in the art to be between 0.5 wt% and 4 wt% of the PUR/PIR foam, based on the reactants envisaged.

According to one possibility provided by the invention, during stage a) of the preparation process, the mixture of chemical components may comprise a plasticizer, for example a polybasic, preferably dibasic, ester of a carboxylic acid with a monohydric alcohol, or may consist of a polymeric plasticizer, such as a polyester of adipic acid, sebacic acid and/or phthalic acid. The amount of plasticizer envisaged is known to the person skilled in the art from the reactants used and is generally between 0.05% and 7.5% by weight of the polyurethane/polyisocyanurate foam.

Organic and/or inorganic fillers, in particular reinforcing fillers, such as siliceous minerals, metal oxides (for example kaolin, titanium or iron oxides) and/or metal salts, are also envisaged in the mixture of chemical components. If they are present in the mixture, the amount of these fillers is generally between 0.5% and 15% by weight of the PUR/PIR foam.

It should be noted that the present invention is not intended to provide technical teaching to the formation of PUR/PIR foams in terms of the nature of the basic chemical components and optional functional agents and their respective amounts. The person skilled in the art knows how to obtain different types of fiber-reinforced PUR/PIR foams and the preparation thereof involves a specific choice from the properties of the fiber reinforcement, in particular the fiber density in the fiber reinforcement and from the foam used to impregnate the reinforcement.

Thus, as shown herein, the object of the present invention is not primarily to a new chemical preparation of fiber reinforced PUR/PIR foams, but rather to a novel fiber reinforced PUR/PIR foam block, wherein the fiber reinforced foam block does not undergo any sagging (or minimal sagging) or any deformation of the conventional parallelepiped shape/structure by virtue of the unique gradient of fiber density along the thickness or height of the block.

Thus, as can be seen in fig. 1, a plurality of fiber reinforcement bodies 10 are unwound and conveyed along a parallel arrangement to each other on or over a conveyor belt 11 intended to carry these reinforcement bodies 10 and the components forming the PUR/PIR foam. This is because in the context of the present invention, the impregnation of the fiber reinforcement 10 is performed by gravity, i.e. the mixture 12 of chemical components, foaming agent and optionally other functional agents for obtaining the PUR/PIR foam is poured directly onto the fibers 10 from a liquid dispenser located above the fiber reinforcement 10.

Therefore, the above-mentioned mixture 12 must be emulsified for a time t_cDuring which the fiber reinforcement 10 is impregnated in a very uniform manner, whether these reinforcements involve several felts or several fabrics, so that the PUR/PIR foam begins to expand after the fiber reinforcement 10 determines that it is totally impregnated with the mixture 12 or at the earliest just at the moment the fiber reinforcement 10 determines that it is totally impregnated with the mixture 12. In this case, by observing the properties of the fiber reinforcement and the PUR/PIR foam as defined according to the invention, an expansion of the PUR/PIR foam is achieved while maintaining a perfect specific distribution of the fibers 10 in the volume of the PUR/PIR foam bun, so that the desired fiber density gradient is obtained.

The subject of the invention is achieved by positioning the fiber reinforcements parallel to one another, i.e. in the form of a stack, each of these reinforcements making it possible to achieve a fiber density, i.e. relative to the fiber weight of the fiber-reinforced foam-greater or smaller relative to the others, taking into account a given volume. Thus, the top layer of fiber reinforcement may achieve a greater fiber density than the bottom layer. More specifically, the fiber density of the upper fiber reinforcement is at least equal to the fiber density of the lower fiber reinforcement if all fiber reinforcements are considered, and the fiber density of the upper fiber reinforcement (i.e. those at the top of the lay-up) is at least twice, in fact even preferably at least three times, the fiber density of the lower fiber reinforcement (i.e. those at the bottom of the lay-up) if all fiber reinforcements are considered.

In the context of the present invention, the local density of the fibers is expressed in the fiber reinforced foam block, which also corresponds to the definition of the fiber density in the upper half of the block being 10% to 35% by weight of fibers, preferably 10.01% to 25% by weight of fibers, and the fiber density in the lower half of the PUR/PIR foam block being 1% to 9.99% by weight of fibers, preferably 6% to 9.9% by weight of fibers.

According to another expression of the invention, a positive gradient of the density of the fibers in the cake (by weight of the foam cake) establishes, from its bottom face to its top face, a range from (+) 0.1% to (+) 2% by weight per cm of fiber, preferably from (+) 0.05% to (+) 1.5% by weight per cm of fiber, more preferably from (+) 0.2% to (+) 1.2% by weight per cm of fiber. Of course, here, this is the average gradient calculated with respect to the height or thickness of the fiber-reinforced foam block.

In the context of the present invention, the emulsification times of the components of the mixture 12 to form the PUR/PIR foam are known to the person skilled in the art and are selected in the following manner: the conveyor belt 11 conveys the composition formed by the mixture 12 of components, blowing agent and fibres 10, for example to a double belt laminator (not shown in the figures), just before the expansion of the foam starts, in other words the expansion of the PUR/PIR foam ends in the double belt laminator.

In such an embodiment with a Double Belt Laminator (DBL), a pressure system with one or two rollers is optionally provided before the double belt laminator, i.e. between the area for impregnating the mixture on the fibers and the double belt laminator. In the case of DBL, the volumetric expansion of the foam is carried out in a laminator when the expansion volume of the foam reaches between 30% and 60% of the expansion volume of the same foam without any constraint (the expansion is free). In this case, the dual band laminator will be able to limit the expansion of the PUR/PIR foam in the second expansion stage when its expansion is near or relatively near its maximum expansion, i.e. when it expands such that the foam is close to all the walls of the dual band laminator forming a channel of rectangular or square cross-section. According to different ways of presenting a particular choice of preparation according to the invention, the gel point of the component mixture, i.e. the moment when the component mixture reaches at least 60% of polymerization, in other words the moment when the maximum volume expansion of the mixture is between 70% and 80%, should occur in the dual-band laminator, possibly in the latter half of the length of the dual-band laminator (i.e. the part closer to the outlet of the laminator than to the laminator inlet).

The function regarding simultaneous dispensing of the mixture 12 of chemical components and foaming agent across the width L of the fibre-reinforced body 10 is here provided by a controlled liquid dispenser 15 shown in fig. 2. Such a dispenser 15 comprises a feed channel 16 for a composition formed by a mixture 12 of chemical components from a reservoir (not shown in the drawings) forming a reactant mixer and at least a blowing agent, where, on the one hand, all chemical components are mixed with the blowing agent and, on the other hand, a particular nucleation of such a mixture, indeed even heating, takes place. This liquid composition formed by the mixture 12 of chemical components and foaming agent is then distributed under pressure in two channels 17, the two channels 17 extending transversely to the respective ends of two identical distribution panels 18, extending along a width L (each having a length substantially equal to L/2), comprising a plurality of nozzles 19 for causing the flow of said mixture 12 over the fiber-reinforced body 10. These flow nozzles 19 consist of holes having a calibrated section of predetermined length. The length of these flow nozzles 19 is thus predetermined so that the liquid exits at the same flow rate between all nozzles 19 so that impregnation of the fiber reinforcement 10 takes place together or simultaneously over a cross section of the width L of the fiber reinforcement 10 and the surface density of the liquid arranged at right angles to each nozzle is equal. In doing so, if considering a cross section of the width L of the fibres 10, they are impregnated simultaneously as the mixture 12 flows under gravity, so that the mixture 12 impregnates the layers of fibres 10 in the same way at all points of the cross section, which helps to obtain, at the outlet of the double belt laminator, a fibre-reinforced foam block in which the local density of the fibres corresponds exactly to the density of the fibres of each stack of fibre reinforcement.

The controlled liquid distributor 15 shown in this fig. 2 is an exemplary embodiment using two identical distribution panels 18, but different designs are conceivable as long as the function of distributing liquid over the width cross section of the fibre 10 simultaneously is achieved. Of course, the main technical feature used in this example is that the different lengths of the flow nozzles 19, in terms of nozzle 19 considered, are more or less dependent on the course or path of the liquid mixture 12 starting from the feed pipe 16 of the distributor 15.

Emulsification time t for exactly on PUR/PIR foams_cAn important aspect of the previous realization of good impregnation of the fiber reinforcement 10 is that the specific viscosity of the selection liquid (mixture 12 consisting of chemical components and foaming agent) is linked to the specific properties of the different fiber reinforcements, which may vary with the fiber density. The viscosity range and the permeability properties of the fiber reinforcement must be chosen such that good penetration of liquid into the first layer of fibers 10 is possible in order to reach the layers below up to the final layer (lower layer of fibers 10, i.e. the lowermost layer of the stack of fiber reinforcements) such that the resulting impregnation time t of the fibers 10 is such that_iSubstantially corresponding to, but always less than, the emulsification time t given by the chemical composition _cWithin a time period of (c). The viscosity of the mixture of components 12 is selected, for example by heating, adding plasticizers and/or by more or less nucleation, such that all fibers 10 in a cross section of the width L are impregnated by the mixture of chemical components and blowing agent 12 just before the emulsification time, i.e. at or just before the beginning of the PUR/PIR foam expansion.

The fiber-reinforced foam blocks are intended for very specific environments and therefore have to guarantee specific mechanical and thermal properties. Thus, the fiber-reinforced foam block obtained according to the production method of the invention generally forms part of the insulating body 30 intended to receive an extremely cold liquid (such as LNG or LPG), i.e. in the example used in fig. 3, the upper or main panel 31 and/or the lower or secondary panel 32 of the insulating body 30 of the storage tank 71. Such storage tanks 71 may be equipped, for example, with ground storage tanks, floating barges, etc. (such as FSRU "floating storage regasification unit" or FGNL "floating liquefied natural gas") or vessels that transport such high-energy liquids between two ports, such as GNL tankers.

The foam block according to the invention shown in fig. 4 comprises a plurality of anchors 40 distributed over different faces of the foam block, namely a top face 41 and side faces 42, 43. These anchors 40 are placed flush with the surface of said faces 41, 42, 43 of the foam block, without exhibiting a foam thickness (or not being so thick) covering it and/or protecting it from external influences.

Fig. 5 shows an embodiment of such an anchor 40 in a cut-away view. The anchor 40 has a plate 44 extending along a plane. The plate 44 comprises a plurality of holes 45 consisting of mechanical anchoring means, in other words one of the two elements makes it possible to fix the foam blocks in or to the insulating body of the tank when engaged with the elements of the insulating body (not shown in the figures). The plate 44 also includes a plurality of identical fixing studs 46 and a central fixing stud 47 having a larger size than the fixing studs 46. The function of these

studs

46, 47 consists in securing as good as possible the anchor 40 in the fibre-reinforced foam block according to the invention. The fixation studs 46 are desirably circumferentially positioned to form a circle near the circumference or perimeter of the anchor 40.

The anchor 40 as shown in fig. 5 is advantageously placed on the conveyor belt 11, then the

studs

46, 47 are oriented upwards and the plate 44 rests on said belt 11.

However, it is also conceivable to place these anchors 40 on the top surface 41 of the block, in fact even on the side surfaces 42, 43, as can be seen on the block shown in fig. 4. In the latter case, the

studs

46, 47 may advantageously be embedded at least slightly into the adjacent/neighbouring fibre mats before the fibre mats are impregnated with the polymer foam.

Of course, one of these holes 45 of the anchor 40 may be used, for example, to form the concave portion of the anchor, but it may also be provided that the anchor requires the use of a plurality of holes 45. Furthermore, these holes 45 are composed of an anchoring solution, but the invention is in no way limited to this embodiment and one or more anchors 40 of different shapes and different mechanical characteristics can be envisaged.

Referring to fig. 6, a cut-away view of an LNG tanker 70 shows a substantially prismatic sealed insulated storage tank 71 mounted in the double hull 72 of a marine vessel. The walls of the tank 71 include: a primary sealing barrier intended to be in contact with the LNG contained in the tank; a secondary sealing barrier arranged between the primary sealing barrier and the double hull 72 of the vessel; and two thermal insulation barriers disposed between the primary and secondary sealing barriers and between the secondary sealing barrier and the twin hull 72, respectively.

In a manner known per se, a loading/unloading pipe 73 positioned on the upper deck of the vessel may be connected to a shipping or harbour terminal by means of suitable connectors for transferring LNG cargo from the storage tank 71 or for transferring LNG cargo to the storage tank 71.

Fig. 6 shows an example of a shipping terminal comprising a loading dock 75, a subsea pipeline 76 and an onshore facility 77. Terminal 75 is a fixed offshore facility that includes a travel arm 74 and a tower 78, tower 78 supporting travel arm 74. The moving arm 74 has an insulated flexible tube bundle 79, which can be connected to the loading/unloading duct 73. The rotating moving arm 74 can accommodate all sizes of LNG tankers. Connecting tubes (not shown) extend within tower 78. The loading and unloading station 75 allows the LNG tanker 70 to be offloaded to or loaded from an onshore facility 77. The onshore facility 77 includes a liquefied gas storage tank 80 and a connecting pipeline 81, the connecting pipeline 81 being connected to the loading and unloading station 75 through the submarine pipeline 76. The subsea pipeline 76 allows liquefied gas to be transported over long distances (e.g., 5km) between the loading and unloading station 75 and the onshore facility 77, which allows the LNG tanker 70 to be maintained at a long distance from shore during loading and unloading operations.

The pressure required to deliver the liquefied gas is generated using pumps onboard the vessel 70 and/or pumps onboard the onshore facility 77 and/or pumps onboard the loading dock 75.

As mentioned above, the subject of the invention, i.e. the use or application in respect of fiber-reinforced polyurethane/polyisocyanurate foam blocks, is not intended to be limited to integrated tanks in support structures, but is also applicable to tanks of the type B and C of the IGC rules valid at the date of filing of the present patent application, but also to future versions of the rules, unless very significant modifications are made to these tanks of type B and C, it being further understood that under this assumption of modifications to the IGC rules, other types of tanks may become conceivable for use in the fiber-reinforced PUR/PIR foam blocks according to the invention.

Next, the subject matter of the invention and its scope can be evaluated by partial experiments and tests carried out by the applicant company, and it is considered that other tests/experiments have been carried out and that it will be obligatory to subsequently provide these other tests/experiments, if necessary/required.

The invention was demonstrated using a polyurethane foam composition with fibers incorporated in the form of a felt, these fibers being always long to continuous fibers; more precisely, the length of these fibers is exactly the same in the composition according to the invention and in the composition according to the prior art. The applicant company tested the subject of the invention with short or in the form of a fabric, in particular, and obtained results identical or practically similar to those obtained with long to continuous fiber mats, as shown below.

Thus, in order to ensure that only the specific characteristics of the fiber density of the fiber reinforcement are combined with the selection of a PUR foam, which in particular exhibits a specific emulsification time, or only one characteristic which is suitable for the fiber reinforcement, the other parameters of the production of PIR foam cakes are not changed or differ between the production according to the invention and the production according to the prior art. As non-exhaustive examples, the following facts may be mentioned: the distance between the nucleation, the amount of blowing agent, the reaction temperature, the nature and amount of the mixture of chemical components, the casting process, the casting and the DBL of the mixture of chemical components which can achieve free expansion or the means which make free expansion possible (if appropriate) is strictly identical in the case according to the invention and in the case according to the prior art.

Of course, in this case, the use of PUR foam has been chosen to illustrate the invention for the sake of clarity and brevity, but equivalent or almost similar results have been obtained using PIR foam and PUR/PIR mixtures.

Also, the results show that the following fiber reinforced foam preparation uses the free expansion technique, but the applicant company has shown that equivalent or almost similar results have been obtained with DBL from the point of view of the fiber reinforced foam according to the invention and the fiber reinforced foam according to the prior art.

Furthermore, it is understood that all compositions in successive tests are considered under the same density conditions, and that this density parameter is related to the performance quality assessment in terms of compressive strength.

For the compositions according to the prior art, the fiber reinforcement and PUR foam are characterized as follows:

[ Table 1]

For the composition according to the invention, the fiber reinforcement and the PUR foam are characterized as follows:

[ Table 2]

It should be noted that the emulsification times used for the above-described PUR foams should be logically identical for the compositions according to the prior art and according to the invention, since the foams used are in any case identical.

After the tests, some results are given below in a simplified manner, illustrating the findings of the applicant company in the case where the fiber reinforcement is provided at least in the form of a glass fiber mat.

[ Table 3]

It should be noted that the first composition of table 3 above (8 layers of U809 or U801 of blocks 180mm thick) consists of a composition according to document FR 2882756. The results of such a composition according to this document are significantly inferior to those obtained with the composition according to the invention (last composition of table 3).

As can be seen from the results given in the table above, the fiber reinforced foam according to the present invention shows significantly better results than the fiber reinforced foam according to the prior art for the three criteria considered for comparing the obtained fiber reinforced foams.

Furthermore, it should be noted that the fiber reinforced PUR/PIR foams according to the present invention do not show any significant deterioration of the properties related to the (very low) thermal conductivity. Thus, for example, for a fiber reinforced foam according to the present invention, exhibiting a fiber density gradient of 1 wt% per cm (from the bottom surface to the top surface of the fiber reinforced foam block), the following thermal conductivity values were obtained:

[ Table 4]

Although the invention has been described in connection with a number of specific embodiments, it is evident that the invention is not limited thereto in any way and that it comprises all technical equivalents of the described means and combinations thereof, provided that they fall within the scope of the invention.

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

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 for sealing an insulation body (30) of an insulation can, wherein the fiber reinforced foam block has a density of 30kg/m ³To 300kg/m³The fiber-reinforced polyurethane/polyisocyanurate foam block has an average fiber density T of between 1% and 60%, preferably between 2% and 30%, by weight of the fibers (10)_fAnd having a width L of at least 10 cm, advantageously between 10 cm and 500 cm, and a thickness (E) of at least 10 cm, advantageously between 10 cm and 100 cm, from the top face to the bottom face of the block, the fiber-reinforced polyurethane/polyisocyanurate foam block consisting of cells storing a gas, advantageously of low thermal conductivity, characterized in that:

the fiber density increases along the thickness E from the bottom surface to the top surface (41) of the mass from a lower density range of 1% to 9.99% by weight of the fibers (10) to an upper density range of 10% to 35% by weight of the fibers (10).

2. The fiber reinforced polyurethane/polyisocyanurate foam block (20) according to claim 1, wherein the fiber reinforced foam block has a density of 50kg/m³To 250kg/m³Preferably between 90kg/m³And 210kg/m³In the meantime.

3. The fiber reinforced polyurethane/polyisocyanurate foam block according to claim 1 or 2, wherein the increase in fiber density relative to the total weight of the fiber reinforced polyurethane/polyisocyanurate foam corresponds to an increase gradient of between 0.05% and 1.5% by weight per cm of fiber, preferably between 0.2% and 1.2% by weight per cm of fiber.

4. Fiber reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, wherein at least 60%, preferably at least 80% of the cells storing a gas advantageously having a low thermal conductivity have an elongated or elongated shape along an axis parallel to the axis of the thickness E of the fiber reinforced polyurethane/polyisocyanurate foam block.

5. Fiber reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, wherein the fibers consist of glass fibers or sisal fibers, preferably glass fibers.

6. The fiber reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, wherein the fibers are long to continuous fibers.

7. The fiber reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, wherein the average fiber density T_fBetween 2% and 25%, preferably between 4% and 15%.

8. The fiber reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, wherein the lower limit of the fiber density ranges from 2% to 6% by weight of the fiber (10); and the upper limit of the fiber density ranges from 12% to 25% by weight of the fiber (10).

9. A fibre reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, wherein the bottom and/or top face (41), preferably the top face (41), of the block has an anchor (40) engageable with engagement means of the insulating body (30) to anchor the foam block to the body (30), preferably the anchor (40) is made of a different material than the foam or the fibres.

10. A fiber reinforced polyurethane/polyisocyanurate foam block according to any of the preceding claims, comprising organic phosphorus type or inorganic flame retardant in the ratio of 0.1 wt% and 5 wt%, 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; the inorganic flame-retardant agent is advantageously red phosphorus, expandable graphite, hydrated aluminum oxide, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulphate or cyanuric acid derivatives, or mixtures thereof.

11. A sealed, thermally insulated tank, said tank consisting of:

a tank integrated in a support structure comprising a sealed and thermally insulated tank comprising at least one sealed metal film consisting of a plurality of metal strakes or plates, which can comprise corrugations, and an insulating body (30) comprising at least one insulating barrier adjacent to the film, or

Tank of type A, B or C, as defined according to the IGC regulations, comprising at least one insulating body (30),

characterized in that the insulating body (30) comprises a plurality of fibre-reinforced polyurethane/polyisocyanurate foam blocks according to any of the preceding claims.

12. A vessel (70) for transporting cold liquid products, said vessel comprising at least one hull (72) and one sealed and insulated tank (71) according to claim 11, said tank being positioned in said hull or mounted on said vessel (70) when said tank is a type a, B or C tank as defined according to IGC regulations.

13. A conveying system for cold liquid products, the system comprising a vessel (70) according to the preceding claim; an insulated duct (73, 76, 79, 81) arranged to connect a tank (71) mounted in the hull of the vessel to a floating or onshore storage unit (77); and a pump for driving a flow of cold liquid product through the insulated conduit from the floating or onshore storage unit to the vessel (70) or from the vessel (70) to the floating or onshore storage unit.

14. A method for loading or unloading a vessel (70) according to claim 12, wherein the cold liquid product is transported from a floating or onshore storage unit (77) to the vessel (71) or from the vessel (70) to a floating or onshore storage unit (77) through insulated conduits (73, 76, 79, 81).

15. A process for the preparation of a fiber reinforced polyurethane/polyisocyanurate foam block for the insulation body of a sealed insulation tank according to any of claims 1-10, characterized in that the process comprises the following stages:

a) mixing (12) the chemical components required for obtaining a polyurethane/polyisocyanurate foam, optionally at least one reaction catalyst, optionally at least one emulsifier and at least one blowing agent, wherein the components comprise the reactants for obtaining polyurethane/polyisocyanurate,

b) impregnating a plurality of fibre-reinforcement bodies (10) positioned in a stack and having a variable density by gravity flow of a mixture (12) of said chemical components, the fibre density of the top reinforcement layer being at least equal to the fibre density of the bottom reinforcement layer, wherein the fibre-reinforcement bodies (10) extend substantially in a direction perpendicular to the direction of the gravity flow,

c) Forming and expanding the fiber reinforced polyurethane/polyisocyanurate foam,

Wherein the expansion of the fiber reinforced polyurethane/polyisocyanurate foam is physically confined by the walls of a two-belt laminator, preferably physically confined by a rectangular cross-section tunnel formed by the walls of the two-belt laminator, the distance between the transversely positioned walls of the rectangular cross-section tunnel being L and the distance between the horizontally positioned walls being (E), thereby encapsulating the expanded fiber reinforced foam to obtain the fiber reinforced polyurethane/polyisocyanurate foam block.