WO2020193874A1

WO2020193874A1 - Polyurethane/polyisocyanurate foam block of a thermal insulation mass of a vessel, and preparation process thereof

Info

Publication number: WO2020193874A1
Application number: PCT/FR2020/000059
Authority: WO
Inventors: Guillaume De Combarieu; Bruno Deletre; Florian CLOUP
Original assignee: Gaztransport Et Technigaz
Priority date: 2019-03-26
Filing date: 2020-03-16
Publication date: 2020-10-01
Also published as: JP7541996B2; FR3094451B1; JP2022528619A; FR3094451A1; EP3947504A1; CN113631611A; CN113631611B; KR20210146953A; SG11202110316VA

Abstract

The invention relates to a fibrous polyurethane/polyisocyanurate foam block in which the fiber density increases along its thickness from the lower face of the block to its upper face, from a lower density range of 1% to 9.99% by weight of fibers (10) to an upper density range of 10% to 35% by weight of fibers (10).

Description

Title of the invention: Polyurethane / polyisocyanurate foam block of a thermal insulation block of a tank and its preparation process

[0001] [The invention relates to blocks of polyurethane (PUR) and / or polyisocyanurate (PIR) foams mounted in a thermal insulation block which must have, given their specific applications,

very particular mechanical and thermal characteristics, while being as economical as possible to produce, said blocks of foam being used within a tank, integrated in a membrane structure (also called an integrated tank) or self-supporting / semi-supporting type A, B or C, used to accommodate extremely cold fluids, called cryogenic, such as in particular Liquefied Natural Gas (LNG) or Liquefied Petroleum Gas (LPG).

[0002] The present invention also relates to a process for preparing these foam blocks from at least one polyisocyanate and at least one polyol.

Finally, the present invention relates more particularly to a sealed and thermally insulating tank using such foams, a vessel equipped with at least one such tank, a method of loading / unloading such a vessel and a transfer system for a liquid product contained in such a vessel.

[0004] PUR polyurethane foam is a cellular insulator, composed of fine cells which store a gas which may have low thermal conductivity. PUR foam is used in a large number of applications such as the automotive industry as flexible PUR foam or in thermal insulation as rigid PUR foam. 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 (compound carrying at least two hydroxy groups), a polyisocyanate (compound carrying at least two isocyanate — NCO functions) and an expanding agent, also designated by expression "blowing agent". This condensation reaction is in particular catalyzed by compounds with basic and / or nucleophilic characters such as tertiary amines or metal-carboxylate coordination complexes such as tin or bismuth salts. Polyols commonly used in

Manufacturing PUR foams are polyether polyols or polyester polyols. Thus, a large number of compounds are necessary for the formation of PUR foam.

[0005] Polyisocyanurate (PIR) and polyurethane / polyisocyanurate (PUR-PIR) foams are also used in the building industry (construction / renovation) and have the advantage of providing better fire-resistant properties as well as a higher compressive strength than PUR. The process for forming these foams is similar to the process for forming PUR foams. In fact, obtaining PUR, PIR and PUR-PIR foams depends on the ratio

isocyanate / polyol.

[0006] PUR, PIR and PUR-PIR foams are well known to those skilled in the art, nevertheless the addition of fibers involves specific technical problems, such as the need for good impregnation of the fibers, so that at the present time, there are no such foams exhibiting at least locally a relatively substantial amount of fibers.

[0007] Now, in the technical field specific to the use of such foams for a thermal insulation block of a tank, the block is subjected to very cold temperatures on its face exposed to the internal space of the tank , for example of the order of -160 ° C in the case of LNG, while the external space of the vessel, typically the hull of a ship, often has a temperature

of environment much higher, at least equal, even very largely

higher than that of ambient air or the sea, considered to be around 20 ° C.

[0008] Thus, the block of PUR, PIR and PUR-PIR foam used in the solid

thermal insulation of such a tank undergoes, during the loading of the extremely cold fluid, said cryogenic, a very significant temperature gradient in its thickness which causes heterogeneous contraction phenomena of the foam block. This heterogeneous contraction of the foam block induces a bimetal effect which leads to a flexing of the block along its longitudinal axis - the two ends having a tendency to rise significantly - due to the non-uniform contraction of the latter in the thickness. The foam block being conventionally fixed mechanically or by gluing, this deflection critically lowers the exploitable mechanical properties of the PUR, PIR and PUR-PIR foam block, or even locally the thermal properties of the thermal insulation block (integrating the foam block according to l 'invention).

This bimetallic effect or bending effect phenomenon of the foam block has been accentuated in recent years due to the fact that the thickness of the foam blocks forming the thermal insulation has been increased, sometimes very significantly. for such tanks housing a cryogenic liquid. In particular, when these tanks have a double thermal insulation layer, conventionally referred to as a "primary" and "secondary" layer (the so-called secondary layer being located furthest from the cryogenic liquid), the thickness E of the thermal insulation

secondary has increased very significantly in recent structures, for example of the MARK type. Thus, the thickness E of the secondary thermal insulation layer has been reduced from 170 mm (millimeter) in a MARK III structure, to 300 mm in a MARK III Flex structure and then to 380 mm in a MARK III Flex + structure.

[0010] This bimetallic effect or this sagging of the thermal insulation layer

secondary has particularly harmful structural consequences on the thermal insulation block, of a sealed and thermally insulating tank, when the thickness of this secondary layer increases significantly relative to the thickness of the primary thermal insulation layer.

Structures such as those described in the documents are known

FR 2882756, WO 2017/202667 and JP 2005225945 but none provides a satisfactory solution to the particular technical problems set out above.

[0012] At the present time, there is no block of polyurethane and / or polyisocyanurate foam, fiber-reinforced or non-fiber, making it possible to respond effectively to this problem, in other words a PUR, PIR and PUR foam block. PIR exhibiting thermomechanical stability between its initial state (in a homogeneous thermal environment) and its operating state, namely when it is used in a vessel containing a cryogenic liquid. To overcome this problem of distortions or geometric instability between these two states of the foam block, is currently produced specially shaped foam blocks, including incorporating notches, or reduced dimensions, of so as to limit the thermal distortion of each of the (small) volume elements or (small) foam blocks within an acceptable range. The need to produce these small foam blocks entails a great number of operations for cutting, placing and joining them to one another, which represents substantial costs. Moreover, the presence of numerous expansion joints very significantly degrades the thermal performance of the tank.

It is in this context that the applicant has succeeded in developing a process for the production of polyurethane (PUR) foams and / or

polyisocyanurate (PIR) containing fibers in significant quantity allowing both obtaining a fiber foam having excellent mechanical and thermal properties, while retaining, over the entire block of foam, in particular its mechanical properties as well than its shape / structure, when the block is in use, that is to say in a very different thermal environment between its two faces, upper and lower.

The present invention thus intends to remedy the shortcomings of the state of

technique by proposing a particularly effective solution for industrially obtaining a fiber-reinforced PUR / PIR foam, possibly of (very) large dimensions, whose mechanical / thermal properties are optimal and at least substantially similar between its initial state - at rest, the block of foam in a substantially homogeneous thermal environment - and its state of use in which the foam block is in a very heterogeneous thermal environment, the temperature difference between its upper face and its lower face, considered according to the thickness E of the block, being at least equal to 80 ° C, or even at least equal to 100 ° C.

It was discovered by the Applicant, after various studies and analyzes, a block of polyurethane foam (PUR) and / or polyisocyanurate (PIR) fiber, and its preparation for its manufacture / design, capable of solving the technical problems related to the very significant modification of the thermal environment of the PUR / PIR foam block during its use.

[0017] Advantageously, it is also possible, according to a preferred embodiment, to very significantly reduce the cost of producing such a fiber-reinforced foam by very significantly reducing the loss of material from the foam block, conventionally necessary according to prior art when cutting the foam block.

Thus, the present invention relates to a block of foam

polyurethane / polyisocyanurate fiber from a thermal insulation block from a sealed and thermally insulating tank, the density of the block of fiber foam is between 30 and 300 kg / m ³ , the block of foam is

fiber-reinforced polyurethane / polyisocyanurate having an average fiber density Tf of between 1% and 60% by mass of fibers, preferably between 2% and 30%, and having a width L of at least ten centimeters, advantageously between 10 and 500 centimeters, and a thickness E, from the lower face of said block to its upper face, of at least ten centimeters, advantageously between 10 and 100 centimeters, the block of fibered polyurethane / polyisocyanurate foam being composed of cells storing a gas, advantageously of low thermal conductivity.

The block of fibered polyurethane / polyisocyanurate foam consists, at least 95% by mass of said block, of cells storing a gas, advantageously of low thermal conductivity, of the foam

polyurethane / polyisocyanurate and fibers.

The foam block according to the invention consists (only) of polyurethane (PUR) and / or polyisocyanurate (PIR) foam, fibers, which are preferably of a single nature such as glass fibers , and gas trapped in the cells, and optionally a minimal portion, for example, of fillers or other functional adjuvants, or for the latter a maximum of 5% by mass, or even preferably a maximum of 2% or of 1% by mass of the foam block according to the invention (the foam block of

at least 98% or 99% by mass of said block, at least 98% or 99% by mass of said block, of cells storing a gas, foam polyurethane / polyisocyanurate and fibers). Indeed, the foam block according to the invention is obtained:

- in a single foam preparation operation (mixing of

reaction ingredients, optionally fillers / adjuvants, with the fibers), preferably in a double strip laminator (DBL);

- in the above operation completed by a cutting operation,

typically from the upper face of the block which has expanded freely on this face.

The aforesaid foam is characterized in that the fiber density increases according to the thickness E, from the lower face of said block to its upper face, by a lower density range of between 1% and 9.99 % by mass of fibers at a higher density range of between 10% and 35% by mass of fibers.

The present invention is intended to apply in particular, but not

exclusively, in the case where the foam block is installed at the level of the secondary layer, conventionally referred to as the “secondary”. In this application, preferably, the foam block has a thickness of at least twenty-five (25) centimeters (cm), even more preferably at least 30 or 35 cm.

[0023] The expression "lower domain" and "domain

upper "two identical parts of the block of fiber-reinforced foam cut along a median plane of said block passing through the middle of the block according to thickness E (or the height of the block when it is positioned in the thermal insulation block).

The terms "upper" and "lower" are understood to mean a meaning or a direction given to the foam block once the latter is in position in the thermal insulation block of a tank. Thus, the part or the upper face of the foam block is that located near or on the side of the container of the tank, when the thermal insulation block is placed in the tank, while the lower part or face of the block of foam is that located towards or on the side of the outside of the tank, that is to say in particular towards the hull of a ship in the case where the tank is integrated or mounted in a cryogenic liquid transport and / or storage vessel.

It is thus understood that, during the manufacture or preparation of the foam block, these concepts or terms of "upper" or "lower" do not yet have any meaning since the foam block is not yet installed in the thermal insulation block of a tank. In other words, we can perfectly prepare the foam blocks according to the invention so that they are obtained, at the outlet of their preparation / production line, with a position opposite to that of their final assembly / assembly in the solid mass thermal insulation of a tank.

The expression "cells storing a gas" is understood to mean the fact that the polyurethane / polyisocyanurate foam has closed cells enclosing a gas, preferably exhibiting low thermal conductivity, originating from a gas injected during a step of nucleation of the reaction mixture or originating, directly or indirectly, from the chemical or physical blowing agent.

The term "fiber (s)" or the expression "fiber reinforcement" is understood to mean the fact that the fibers can be in two distinct forms:

[0028] - or in the form of at least one fabric of fibers, in which the fibers are perfectly aligned in at least one direction, in other words the fibers have at least one preferred direction of fibers. The expression "fiber fabric" per se refers to a clear technical definition known to those skilled in the art,

[0029] - or in the form of at least one fiber mat, in which the fibers do not

have no defined orientation, in other words these fibers are oriented isotropically essentially along the main plane of the mat layer. Again, the expression "fiber mat" per se refers to a clear technical definition known to those skilled in the art.

[0030] According to one embodiment, the expression "gas

(advantageously) with low thermal conductivity "the gas coming from the blowing agent, or by chemical reaction of the latter when this agent is said" chemical ”, conventionally carbon dioxide (CO2) when the chemical swelling agent consists of water, or by a physical swelling agent such as for example dinitrogen (N2), oxygen (O2), carbon dioxide , the

hydrocarbons, chlorofluorocarbons, hydrochlorocarbons,

hydrofluorocarbons, hydrochlorofluorocarbons, and mixtures thereof, as well as the corresponding alkyl ethers. Physical blowing agents such as molecular nitrogen N2, oxygen O2 or CO2 are found in gas form. These gases are dispersed or dissolved in the liquid mass of copolymer, for example under high pressure, using a static mixer. By depressurizing the system, nucleation and growth of bubbles generates cellular structure.

The expression "average density Tf in fibers" is understood to mean the fiber density expressed as mass of fibers relative to the total mass of the block of fiber-reinforced foam, without considering the local percentages (within the block) which vary from these fibers.

[0032] Thus, the fiber-reinforced foam block is compatible with use in tanks integrated into a supporting structure but also self-supporting / semi-supporting tanks of type A, B or C according to regulations (IMO)

IGC, that is to say as an external insulation associated with self-supporting tanks for the storage and / or transport of very cold liquids such as LNG or LPG.

Finally, the thermal properties of the block of fiber foam are at least

equal to those of the blocks of non-fiber foam of the state of the art, more precisely the block of foam has, in the thickness E, a thermal conductivity of less than 30 mW / mK (milliwatt per meter per Kelvin), i.e. 0 , 03 W / mK, preferably less than 25 mW / mK, even more preferably less than 23 mW / mK, measured at 20 ° C, and a thermal conductivity of less than 20 mW / mK when the top face of the block is found at -160 ° C, the foam block then being in operating condition, the tank in which it is housed containing LNG.

[0034] Other advantageous features of the invention are presented

succinctly below: Preferably, the density of the block of fiber-reinforced foam is between 50 and 250 kg / m ³ , preferably between 90 and 210 kg / m ³ . It should be noted here that for the foam blocks used in a self-supporting tank (types B, C) or semi-supporting (type A), the density range of the fiber foam block is preferably between 30 and 90 kg / m ³ while in the case of a membrane, the even preferred density range is between 90 and 210 kg / m ³ .

Advantageously, the increase in fiber density, related to the

total mass of the polyurethane / polyisocyanurate fiber foam, corresponds to an increase gradient of between 0.05% and 1.5% by mass of fibers per centimeter, preferably between 0.2% and 1.2% by mass fiber per centimeter. These density values are averaged over the entire block.

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

[0038] Preferably, the fibers consist of glass fiber or of hemp fiber, preferably of glass fiber.

[0039] Preferably, the fibers are long to continuous fibers.

The expression "the fibers being long to continuous" (or "

long to continuous fibers') the fact that the fibers, or where appropriate an agglomeration of a set of fibers (fibers bonded or fixed to each other), all have - either at least 90% of the fibers, considered alone or agglomerated forming the equivalent of a single fiber, in total mass of said fibers - a length of at least five (5) centimeters (cm).

Preferably, the average density of Tf fibers is between 2% and

25%, preferably 4% and 15%.

[0042] Preferably, the foam block according to the invention is in a

parallelepiped or cubic shape.

It is of course here that this foam block, having such a shape

parallelepipedal or cubic, may have one or more protuberances local, for example in the form of the anchors presented below, or else conversely empty or hollow portions, while still being able to be qualified as parallelepiped or cubic.

According to a preferred embodiment of the invention, the fiber density in the lower region is between 2% and 6% by weight of fibers and the fiber density in the upper region is between 12% and 25. % by mass of fiber.

Advantageously, the lower face and / or the upper face, preferably the upper face, of said block has (s) anchors able to engage with a means for engaging the thermal insulation block (not shown in the figures). appended figures) in order to fix or anchor the foam block to said solid, preferably said anchors being made of a material other than the foam or fibers.

These anchors are advantageously metallic elements (these

anchors can also be made of plastic / polymers or composites combining one or more polymers with ceramic and / or metallic materials), for example having a hooking tab, in the form of an L, so as to engage with an element or part of the thermal insulation block enclosing or housing the block of fiber foam. This part of the thermal insulation block may consist of a metallic membrane sealing the container, for example of stainless steel or manganese-based, in the case of a membrane tank or of a vapor barrier (having the function of technique of ensuring a seal to the surrounding environment outside the tank) in the case of self-supporting or semi-supporting tanks of type A, B or C. In a possibility offered by the invention, this element or this part of the mass of thermal insulation (in a membrane tank) has a notch or the like intended to allow engagement with a portion of an anchor for the maintenance or mechanical retention of the block of fiber-reinforced foam to the other thermal insulation block elements. Of course, these anchors can also have the function of anchoring the foam block to the hull, in the case of a membrane tank, to the self-supporting structure in the case of a self-supporting tank. of type A, B or C, it being understood that these anchors are then those present on the underside of the foam block.

In the context of the present invention, these anchors are inserted at least in part in the fiber reinforcements, those constituting the lower or upper layer of the fiber reinforcement stack, so as to allow their location on the faces once the block of foam has been prepared / finished, without however protruding from said face.

[0048] Advantageously, these anchors are present only on the face

upper part of the block of fiber-reinforced foam because the fiber density is important, in the context of the present invention, so that the anchors are firmly fixed to the block of fiber-reinforced foam.

Advantageously, the block of fiber-reinforced foam according to the invention comprises a flame retardant in a proportion of between 0.1% and 5% by mass, of the organophosphorus type, advantageously triethylphosphate (TEP), tris (2- chloroiso-propyl) phosphate (TCPP), tris (1, 3-dichloroisopropyl) phosphate (TDCP), tris (2-chloroethyl) phosphate or tris (2,3-dibromopropyl) phosphate, or a mixture of these , or of the inorganic flame retardant type, advantageously red phosphorus, expandable graphite, an aluminum oxide hydrate, an antimony trioxide, an arsenic oxide, an ammonium polyphosphate, a calcium sulfate or cyanuric acid derivatives, a mixture thereof.

The invention also relates to a sealed and thermally insulating tank integrated into a supporting structure, said tank consisting of:

- a tank integrated into a supporting structure comprising a sealed and thermally insulating tank comprising at least one sealed metal membrane composed of a plurality of metal strakes or metal plates which may include corrugations and a thermally insulating mass comprising at least one adjacent thermally insulating barrier to said membrane, or

- a type A, B or C tank according to the definition given by the IGC code comprising at least one thermally insulating block. The tank according to the invention is characterized in that the thermally insulating solid comprises a plurality of blocks of foam

fiber-reinforced polyurethane / polyisocyanurate described briefly above.

The expression "IGC code" is understood to mean the "international collection of rules relating to the construction and equipment of ships transporting liquefied gases in bulk", well known to those skilled in the art, at l 'like the types B and C of tanks cited, or in English “International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk”.

It will be noted that one can use, in particular in the IGC code, the expression "membrane tank (or tank)" instead of the expression "integrated tank" to designate the same category of tanks, fitted in particular to tankers transporting and / or storing at least partly liquefied gas. The “membrane tanks” are integrated in a supporting structure while the tanks of type A, B or C are said to be self-supporting or semi-supporting (type A specifically).

This tank comprises a plurality of blocks of foam

fiber-reinforced polyurethane / polyisocyanurate obtained directly by the aforementioned preparation process.

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

Advantageously, in the case where the tank consists of a tank integrated into a supporting structure (membrane tank), such a vessel comprises at least one sealed and insulating tank as described above, said tank comprising two barriers of 'successive sealing, one primary in contact with a product contained in the tank and the other secondary disposed between the primary barrier and a supporting structure, preferably constituted by at least part of the walls of the vessel, these two barriers of sealing being alternated with two thermally insulating barriers or a single thermally insulating barrier arranged between the primary barrier and the supporting structure.

Such tanks are classically designated as integrated tanks according to the code of the International Maritime Organization (IMO), such as for example tanks of the NO type, including types NO 96 ^® , NO 96L03 ^® , NO

96L03 + ^® or NO 96 MAX ^® , or MARK III ^® , MARK III ^® Flex or FLEX +, preferably NO type tanks.

Preferably, the tank, called membrane type or type A, B or C,

contains Liquefied Natural Gas (LNG) or Liquefied Gas (GL).

The invention also relates to a transfer system for a cold liquid product, the system comprising a vessel as defined above, insulated pipes arranged so as to connect the tank installed in the hull of the vessel to a control unit. floating or terrestrial storage and a pump for driving a flow of cold liquid product through insulated pipelines from or to the floating or terrestrial storage unit to or from the ship.

The invention also relates to a method for loading or unloading a ship as defined above, in which a cold liquid product is conveyed through isolated pipes from or to a floating or terrestrial storage unit towards or from the ship.

The present invention also relates to the process for preparing a block of polyurethane / polyisocyanurate foam fiberized from a thermal insulation block of a sealed and thermally insulating tank as defined briefly above, said process characterized in that it comprises the stages:

a) a mixture of chemical components necessary for obtaining a polyurethane / polyisocyanurate foam, said components comprising reagents for obtaining polyurethane / polyisocyanurate, optionally at least one reaction catalyst, optionally at least one emulsifier, and at least one blowing agent,

b) impregnation, by gravitational flow of the aforesaid mixture of

chemical components, of a plurality of fiber reinforcements, said fiber reinforcements fibers being arranged in superimposed layers and having varying densities, an upper reinforcing layer having a fiber density at least equal to that of the lower reinforcing layer, in which the fiber reinforcements extend essentially in a direction perpendicular to the direction of said gravitational flow,

c) formation and expansion of the polyurethane / polyisocyanurate fiber foam,

wherein the expansion of the fibered polyurethane / polyisocyanurate foam is said to be free, either without the constraint exerted by a volume of closed section, or in which the expansion of the fibered polyurethane / polyisocyanurate foam is physically constrained by walls of 'A double strip laminator, preferably is physically constrained by the walls of a double strip laminator forming a tunnel of rectangular section with a distance between the walls disposed laterally equal to L and a distance between the walls disposed horizontally equal to E, enclosing thus the expanding fiber foam so as to obtain the aforesaid block of foam

polyurethane / polyisocyanurate fiber.

The expression "cream time" is understood to mean the time required, to

counting from the mixture of chemical components (a), so that they start the polymerization reactions and that consequently the mixture of components starts the stage (c) of expansion and crosslinking (= formation of the PUR / PIR foam fibered). This cream time is well known to those skilled in the art. In other words, the cream time is the time elapsed until the mixture turns white under the action of the nucleation of the bubbles (cells storing a gas) and the expansion of the foam after mixing the chemical components. at room temperature. The cream time can be determined visually or with the aid of an ultrasonic sensor detecting a variation in thickness indicating the formation of foam.

By the expression "the fiber reinforcements extend essentially in a direction perpendicular to the direction of the gravitational flow of the mixture of chemical components" (a) is meant the fact that these fiber reinforcements are present in the form of a thin layer spreading, during impregnation step (b), along a plane perpendicular to the direction of flow of said mixture of components. Thus, as can be seen in Fig. 1, the plurality of fiber reinforcements, having a width L and arranged in superimposed layers, are driven in a longitudinal direction I while the mixture of chemical components is deposited on the fiber reinforcements. from a distributor allowing / allowing the gravitational flow of the mixture of chemical components. In other words, the mixture of chemical components, possibly exiting under pressure from the dispenser, falls under the effect of at least its own weight on the stacked fiber layers, thus impregnating these fiber reinforcements from the upper layer to the lower layer. .

Of course, in the case where the foam block according to the invention is prepared by a so-called free expansion, one then proceeds to a cutting of the block at least at the level of the open face allowing said free expansion, conventionally the face. upper, so as to ultimately obtain a foam block whose dimensions and shape, conventionally parallelepiped, are in accordance with the invention.

The use, in the composition according to the invention, of a swelling agent

chemical, can be coupled with that of a physical blowing agent. In this case, the physical blowing agent is preferably mixed in liquid or supercritical form with the foamable (co) polymer composition and then converted to the gas phase during the PUR / PIR foam expansion step.

Chemical and physical blowing agents are well known to those skilled in the art who selects both, in the appropriate amounts, depending on the PUR / PIR foam he wishes to obtain.

By polyols is meant any carbon structure bearing at least two

OH groups.

Obtaining PUR, PIR and PUR-PIR foams depending on the ratio

isocyanate / polyol, a PUR, PIR or PUR-PIR foam will be obtained according to this ratio. When the ratio between a polyol component and an isocyanate component is:

- between 1: 1 and 1: 1, 3 a PUR polyurethane foam will be obtained,

- between 1: 1, 3 and 1: 1, 8 we will obtain a PUR-PIR polyurethane foam,

- between 1: 1, 8 and 1: 2.8, a PIR polyurethane foam will be obtained.

Polyisocyanates suitable for the formation of PUR, PIR and PUR-PIR foam are known to those skilled in the art and include, for example, aromatic, aliphatic, cycloaliphatic, arylaliphatic polyisocyanates and their mixtures, advantageously aromatic polyisocyanates.

Examples of polyisocyanates suitable in the context 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 of the

polymerization of these isomers, toluene 2,4- and 2,6-diisocyanate (TDI), m- and p-phenylene diisocyanate, naphthalene-1, 5-diisocyanate; aliphatic, cycloaliphatic, arylaliphatic isocyanates such as 1, 6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1, 4-cyclohexane diisocyanate (CHDI) , the

bis (isocyanatomethyl) cyclo-hexane (H6XDI, DDI) and tetramethyxylylene diisocyanate (TMXDI). It is also possible to use any mixtures of these diisocyanates. Advantageously, the polyisocyanates are the 4,4'-, 2,4'- and 2,2'- isomers of diphenylmethane diisocyanate (MDI).

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

[0072] According to a preferred embodiment of the invention, advantageously, the

positioning of the tunnel walls of the double strip laminator (DBL) is defined so that the expansion stress of the foam

fiber-reinforced polyurethane / polyisocyanurate leads to a foam volume of polyurethane / polyisocyanurate fiber, at the outlet of the double-strip laminator, representing between 85 and 99%, preferably between 90% and 99%, of the expansion volume of this same polyurethane / polyisocyanurate fiber foam in the case of an expansion free, without the stress of the walls of such a double strip laminator. In this case, a foam is obtained, the cells of which, of ovoid shape, are preferably oriented along the axis E, leading to advantageous properties of resistance to crushing in this direction E (measured according to the ISO 844 standard), combined with properties already described in the plane normal to this axis E. Tests and experiments were carried out by the Applicant to determine the broad and preferred domains mentioned above but are not presented here for the sake of clarity and conciseness.

Thanks to the aforesaid specific parameterization of the stress on expansion of the fiber-reinforced PUR / PIR foam in a DBL, on the one hand, a block of fiber-reinforced PUR / PIR foam is obtained in which at least 60%, generally more than 80% or even more than 90%, cells storing a gas with low thermal conductivity extend longitudinally along an axis parallel to the axis of the thickness E of the foam block and we contribute, in addition to the specific choices related to characteristics of the fiber reinforcements and the viscosity of the mixture of chemical components, perfect homogeneity of the block of fiber foam. These two characteristics - orientation of the cells & homogeneity of the Tf rate of fibers in the block at a considered level of the thickness of the block - make it possible to obtain a block of fiber foam with excellent properties

mechanical according to the thickness E (compressive strength) and in a plane normal to the direction of the thickness (tensile strength and low coefficient of thermal contraction).

[0074] The elongated or stretched shape can be defined by an extended shape in

length, that is to say it has one dimension: its length, greater than its other dimensions (width and thickness).

[0075] According to another embodiment offered by the invention, the expansion of the

Polyurethane / polyisocyanurate fiber foam is free, ie without the stress exerted by a closed section volume. Here, unlike the embodiment of the preparation according to the invention using a DBL, the preparation of the polyurethane / polyisocyanurate foam is said to be "free expansion" insofar as the expansion of the fiber-reinforced foam is not constrained on at least one side or on at least one expansion face so that the swelling of the fiber-reinforced foam is free on this side or this face, unlike a mold defining a volume finished.

Conventionally, free expansion is achieved by omitting the cover

(upper) while the side walls prevent foam overflow to the sides and the foam naturally swells upwards,

possibly beyond the upper ends of these side walls.

[0077] Advantageously, following the step of free expansion of the foam of

polyurethane / fiber-reinforced polyisocyanurate, said fiber-reinforced foam is cut to obtain the aforementioned block of polyurethane / fiber-based polyisocyanurate foam.

According to one possibility offered by the invention, not shown in the appended figures, just after the step of impregnating the fiber reinforcements, the mixture of components and at least the blowing agent impregnating them is applied to the mixture. fibers a pressure application system (which may for example be a roller system, of the type designated "nip roll" in English) intended to apply pressure to the upper face of the assembly consisting of the aforesaid mixture and of the fibers. This pressure system makes it possible, on the one hand, to level the upper face of this assembly and, by the pressure exerted on the assembly, helps to promote the impregnation of the fibers in the aforesaid mixture. This pressure system may consist of a single or a double roller, the relative positions of which, above the liquid assembly, and possibly below the foam support, are adjusted in such a way that the liquid assembly is forced to spread out in a perfectly uniform manner. Thus, in doing so, an equivalent quantity of the liquid assembly is obtained at any point of the section defined by the spacing between the two rollers or of the upper roller and of the conveyor belt. In other words, the main object of this pressure system is to complete the liquid dispensing device in that it contributes to uniformity, in the thickness / width, the liquid assembly before most of its expansion.

Preferably, the dynamic viscosity h of the aforesaid mixture of components is between 30 mPa.s and 3000 mPa.s, preferably between 50 mPa.s and 1500 mPa.s;

Advantageously, at least 60% of the aforesaid cells storing a gas, advantageously of low thermal conductivity, have an elongated or stretched shape along an axis parallel to the axis of a thickness E of the block of polyurethane foam / fibered polyisocyanurate ;

Even more advantageously, at least 80%, preferably at least 90%, of the aforesaid cells storing a gas, advantageously of low thermal conductivity, have an elongated or stretched shape along an axis parallel to the axis of a thickness E of the foam block of

polyurethane / polyisocyanurate fiber;

It is understood here that this characteristic linked to the elongated shape of the cells storing a gas, advantageously of low thermal conductivity, and their rate / proportion in the block according to the invention is more particularly directed in the context of the setting. implementation of the preparation process with a DBL, but it is absolutely not limited to this case. Indeed, in the case of free expansion, more specifically when there is no

upper wall / cover constraining the expansion of the fiber-reinforced foam, such a preferential orientation of the cells storing a gas, advantageously of low thermal conductivity, is also obtained.

Preferably, the (reinforcements of) fibers are arranged over an entire width L and step b) of impregnation of the fibers with the mixture of components, to obtain a polyurethane / polyisocyanurate foam, and a blowing agent operates via a controlled liquid distributor, simultaneously over the entire width L;

The term "simultaneously" is understood to mean the fact that the liquid mixture

(reagents and at least the swelling agent) reaches the fibers, over a section of width L, at the same time all along this section so that the impregnation of the different fiber reinforcements begin or take place, depending on the thickness (or height) of the foam block and for the same section of width, at the same time or at the same speed.

[0085] Advantageously, the blowing agent consists of an expanding agent

physical and / or chemical, preferably a combination of the two types.

Preferably, the physical expansion agent is chosen from alkanes and cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals, fluoroalkanes, fluoroolefins having between 1 and 8 carbon atoms and tetraalkylsilanes having between 1 and 3 carbon atoms in the alkyl chain, in particular tetramethylsilane, or a mixture thereof.

In this hypothesis, by way of example of compounds, it could be

propane, n-butane, isobutane, cyclobutane, n-pentane, isopentane, cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone and fluoroalkanes; the fluoroalkanes being chosen are those which do not degrade the ozone layer, for example

trifluoropropane, 1, 1, 1, 2-tetrafluoroethane, difluoroethane and

heptafluoropropane. Examples of fluoroolefins include 1 -chloro-3,3,3-trifluoropropene, 1, 1, 1, 4,4,4-hexafluorobutene (for example HFO FEA1100 sold by the company Dupont).

[0088] According to a preferred embodiment of the invention, the blowing agent

physical chosen is 1, 1, 1, 3,3-pentafluoropropane, or FIFC-245fa,

(marketed by the company Floneywell), 1, 1, 1, 3,3-pentafluorobutane, or 365mfc, (for example solkane® 365mfc marketed by the company Solvay), 2,3,3, 3-tetrafluoroprop-1 -ene, 1, 1, 1, 2,3,3, 3-heptafluoropropane (also internationally referred to as FIFC-227ea, e.g.

marketed by the company Dupont), 1, 1, 1, 4,4,4-hexafluorobutene (for example FIFO FEA1100 marketed by the company Dupont), trans- 1 - chloro-3,3,3-trifluoropropene (solstice LBA - Honeywell Company) or a mixture of these.

Advantageously, the chemical expansion agent consists of water. Advantageously, during step a) of mixing chemical components, nucleation gas is incorporated into at least one polyol compound, preferably using a static / dynamic mixer at a pressure between 20 and 250 bars, the nucleation gas representing between 0 and 50% by volume of polyol, preferably between 0.05 and 20% by volume of the volume of polyol;

[0091] Preferably, during step a) of mixing the chemical components, the temperature of each of the reagents for obtaining

polyurethane / polyisocyanurate is between 10 ° C and 40 ° C, preferably between 15 ° C and 30 ° C;

Preferably, according to a preferred embodiment of the invention, the

final mixing of the streams of polyols, isocyanate and / or blowing agent takes place in a mixing head at low pressure (<20 bar) or high pressure (> 50 bar) using a dynamic or static mixer.

According to one possibility offered by the invention, is further added to the mixture, in step a), an organophosphorus flame retardant, advantageously triethylphosphate (TEP), tris (2-chloroiso-propyl) phosphate ( TCPP), tris (1, 3- dichloroisopropyl) phosphate (TDCP), tris (2-chloroethyl) phosphate or tris (2,3-dibromopropyl) phosphate, or a mixture thereof, or a flame retardant inorganic, preferably red phosphorus, expandable graphite, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate, calcium sulfate or cyanuric acid derivatives, a mixture of these.

It is also possible to envisage that the flame retardant uses

diethyl ethane phosphonate (DEEP), triethyl phosphate (TEP), propyl phosphonate dimethyl (DMPP) or cresyl diphenyl phosphate (DPC).

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

The description which follows is given purely by way of illustration and not by way of limitation with reference to the appended figures, in which: [0097] [Fig.1] is a schematic view illustrating the different steps of the process for preparing a block of fiber-reinforced PUR / PIR foam according to the invention.

[0098] [Fig.2] is a schematic representation of one embodiment of a controlled liquid dispenser according to the invention.

[0099] [Fig.3] is a schematic view of two sets of thermal insulation panels, fixed one on the other, respectively forming a primary space and a secondary insulation space for a tank, these panels being constituted by a plurality of blocks of polyurethane / polyisocyanurate foam according to the invention.

[0100] [Fig.4] is a partial view of a block of foam according to the invention in which a plurality of anchors have been placed during its preparation so as to allow the fixing or anchoring of said block of foam .

[0101] [Fig.5] illustrates an embodiment of an anchor, visible in a schematic section (cut away), capable of being inserted into a block of foam according to the invention.

[0102] [Fig.6] is a cutaway schematic representation of an LNG tanker, in which are installed the two sets of thermal insulation panels of the type of those shown in Figure 3, and a terminal loading / unloading of this tank.

[0103] Preferably, the preparation of the fiber-reinforced PUR / PIR according to the invention is carried out in the presence of catalysts making it possible to promote the isocyanate-polyol reaction. Such compounds are described, for example, in the prior art document entitled "Kunststoffhandbuch, volume 7, Polyurethane", Imprimerie Cari Flanser, 3rd edition 1993, chapter 3.4.1. These compounds include amine based catalysts and organic compound catalysts.

[0104] Preferably, the preparation of the block of fiber-reinforced PUR / PIR foam according to

the invention is carried out in the presence of one or more stabilizers intended to promote the formation of regular cellular structures during the formation of the foam. These compounds are well known to those skilled in the art and, by way of example, mention may be made of foam stabilizers comprising silicones such as siloxane-oxyalkylene copolymers and other organopolysiloxanes. [0105] Those skilled in the art know the amounts of stabilizers, between 0.5% and 4% by weight of the PUR / PIR foam, to be used depending on the reagents envisaged.

[0106] According to one possibility offered by the invention, during step a) of the preparation process, the mixture of chemical components can include plasticizers, for example polybasic esters, preferably dibasic, carboxylic acids with monohydric alcohols. , or consist of polymeric plasticizers such as polyesters of adipic, sebacic and / or phthalic acids. Those skilled in the art, depending on the reagents used, know what amount of plasticizers to consider, typically from 0.05% to 7.5% by weight of the polyurethane / polyisocyanurate foam.

[0107] Organic and / or inorganic fillers, in particular reinforcing fillers, can also be considered in the mixture of chemical components such as siliceous minerals, metal oxides (for example kaolin, oxides of titanium or of iron) and / or metal salts. The amount of these fillers, if present in the mixture, is

conventionally between 0.5% and 15% by weight of the PUR / PIR foam.

[0108] It should be noted that the present invention does not intend here to add a

technical education in the formation of a PUR / PIR foam, both in terms of the nature of the essential 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 foam and the present preparation relates, from a specific choice of

characteristics of the fiber reinforcements, in particular the density of fibers in the fiber reinforcement, and an equally specific choice of the foam for the impregnation of said reinforcements.

[0109] Thus, the present invention, as explained here, is not primarily aimed at a new chemical preparation of fiber-reinforced PUR / PIR foam but rather a new block of fiber-reinforced PUR / PIR foam in which, thanks to a Specific fiber gradient depending on the thickness or height of the block, this fiber-reinforced foam block does not undergo any sag (or minimal sag) or deformation of its general parallelepipedal shape / structure other than a slight contraction of its dimensions. [0110] Thus, as can be seen in FIG. 1, a plurality of fiber reinforcements 10 is unwound and brought in parallel alignment with one another on or above a conveyor belt 11 intended to lead these reinforcements 10. and the PUR / PIR foam-forming components. In fact, the impregnation of the fiber reinforcements 10 is carried out, within the framework of the present invention, by gravity, that is to say that one flows from a liquid distributor located above the reinforcements of fiber 10, the mixture 12 of chemical components, blowing agent (s) and any other functional agents used to obtain the PUR / PIR foam, directly on the fibers 10.

[0111] Thus, the aforesaid mixture 12 must impregnate all of the fiber reinforcements 10, whether they are for the latter several mats or several fabrics, in a very homogeneous manner, over the time of cream t _c so that the start of the expansion of the PUR / PIR foam takes place after or at the earliest just when the fiber reinforcements 10 are all impregnated with the mixture 12. In doing so, by respecting the characteristics for the fiber reinforcements and the PUR / PIR foam defined according to the invention, the expansion of the PUR / PIR foam is carried out by maintaining a perfect specific distribution of the fibers 10 in the volume of the PUR / PIR foam block, so as to obtain the desired fiber density gradient.

The object of the present invention is achieved by arranging fiber reinforcements parallel to each other, or in superimposed layers, each of these reinforcements making it possible to achieve a fiber density - weight of fibers relative to the weight of the fiber foam considering a given volume - more or less important compared to the others. Thus, the upper fiber reinforcements achieve a higher fiber density than those of the lower layers. More precisely, if we consider all of the fiber reinforcements, the upper fiber reinforcement has a fiber density at least equal to that of the lower fiber reinforcement and, if we consider all the fiber reinforcements , the upper fiber reinforcement - the one at the top of the layers

superimposed - has a fiber density at least twice as high, and preferably at least three times as high, than that of the lower fiber reinforcement (that at the very bottom of the superimposed layers). In the context of the definition of the invention, in which the local density of fibers is expressed in the block of fiber-reinforced foam, this also amounts to defining that the density of fibers in the upper half of the block is between 10 % and 35% by mass of fibers, preferably between 10.01% and 25% by mass of fibers, and from 1% to 9.99% by mass of fibers, preferably between 6% and 9.9% by mass of fibers, in the lower half of the PUR / PIR foam block.

According to another way of expressing the invention, the positive gradient in fiber density (by mass of the foam block) in the block, from its lower face to its upper face, is established in the range of ( +) 0.1% to (+) 2% by mass of fibers per centimeter, preferably from 0.05% to 1.5% by mass of fibers per centimeter and more preferably between 0.2% and 1, 2% by mass of fibers per centimeter. Of course, this is an average gradient calculated on the height or thickness of the block of fiber foam.

In the context of the invention, the cream time of the components of the mixture 12 to form the PUR / PIR foam is known to those skilled in the art and chosen in such a way that the transport belt 11 brings the assembly together. formed from the mixture 12 of components, the blowing agent and the fibers 10 for example up to a double strip laminator, not shown in the accompanying figures, while the expansion of the foam has just started, in other words the PUR / PIR foam expansion then ends in the dual belt laminator.

In such an embodiment with a double strip laminator (DBL), a pressure system, using one or two rollers, is optionally arranged before the double strip laminator, or between the zone of impregnation of the mixture on the fibers and the double strip laminator. In the case of the use of a DBL, the expansion of the volume of the foam is carried out in the laminator when the expansion volume of this foam reaches between 30% and 60% of the expansion volume of this same foam when the expansion is left free, or without any constraint. In doing so, the double belt laminator will be able to constrain the expansion of the PUR / PIR foam in its second expansion phase, when this is close or relatively close to its maximum expansion, that is to say when its expansion brings the foam close to all the walls, forming a tunnel of rectangular or square section, of the double strip laminator. According to a different way of presenting the specific choices of the preparation according to the invention, the freezing point of the mixture of components, that is to say the moment when at least 60% of the polymerization of the mixture of components is reached, in other words 70% to 80% of the maximum volume expansion of the mixture, imperatively takes place in the double strip laminator, possibly in the second half of the length of the double strip laminator (i.e. closer to the exit of the laminator than to the entry of the latter).

[0117] Regarding the function of simultaneous distribution of the mixture 12 of

chemical components and swelling agent over the entire width L of the fiber reinforcements 10, it is here provided by a controlled liquid distributor 15, visible in FIG. 2. Such a distributor 15 comprises a supply channel 16 of the assembly formed of the mixture 12 of chemical components and at least of the swelling agent from the tank forming a reagent mixer, not shown in the appended figures, in which on the one hand all the chemical components and the swelling agent are mixed and d on the other hand, the nucleation, or even the heating, of such a mixture is carried out. This liquid assembly formed of the mixture 12 of chemical components and of the blowing agent is then distributed, under pressure, in two channels 17 extending transversely to respectively end in two identical distribution plates 18, extending along the width L ( each having a length substantially equal to L / 2), comprising a plurality of nozzles 19 for the flow of said mixture 12 over the fiber reinforcements 10. These flow nozzles 19 consist of orifices of calibrated section having a determined length. The length of these flow nozzles 19 is thus determined so that the liquid leaves with an identical flow rate between all the nozzles 19 so that the impregnation of the fiber reinforcements 10 takes place at the same time, or simultaneously, on the section of width L of the fiber reinforcements 10, and that the surface mass of liquid deposited in line with each nozzle is equal. In doing so, if we consider a section of width L of fibers 10, the latter are impregnated

concurrently so that the impregnation of the layers of fibers 10 by the mixture 12 is carried out, at all points of this section, in an identical manner, which contributes to obtaining at the output of the double strip laminator a block of fiber foam in which the local fiber density corresponds precisely to the fiber density of each of the superimposed layers of the fiber reinforcements, at the moment of gravitational casting of the mixture 12.

The controlled liquid distributor 15 shown in this FIG. 2 is a

exemplary embodiment in which two identical distribution plates 18 are used but a different design could be envisaged, insofar as the function of simultaneous liquid distribution over the cross section of the fibers 10 is achieved. Of course, the main technical feature used here lies in the different lengths of the nozzles.

flow 19, more or less long depending on the path, or path, of the liquid mixture 12 from the supply conduit 16 of the distributor 15 to the flow nozzle 19 in question.

[0119] One of the important aspects for achieving good impregnation of

fiber reinforcements 10 just before the cream time t _c of the PUR / PIR foam lies in the choice of a specific viscosity of the liquid (consisting of the mixture 12 of chemical components and the blowing agent) to be bonded with the specific characteristics of the different fiber reinforcements, variable depending on the fiber density. The chosen viscosity range as well as the

permeability characteristics of the fiber reinforcements must allow good penetration of the liquid into the first layers of fibers 10, to reach the following ones up to the last layer (the lower layer of fibers 10, that is to say the one located lowest in the stack fiber reinforcements), so that the impregnation time ti of the fibers 10 is achieved within the time period given by the chemical components corresponding substantially, but always less, to the cream time t _c. The viscosity of the mixture 12 of components is chosen, for example by heating, adding plasticizers and / or by a greater or lesser nucleation, such that the impregnation of all the fibers 10 by the mixture 12 of chemicals and of the swelling agent, over a section of width L, is obtained just before the cream time, that is to say before or just before the beginning of the expansion of the foam of

PUR / PIR. [0120] The block of fiber-reinforced foam is intended for use in a very specific environment, and must therefore guarantee specific mechanical and thermal properties. The fiber-reinforced foam block obtained by the preparation according to the present invention thus conventionally forms part of a thermal insulation block 30, either in the example used in FIG. 3, in a top or primary panel 31 and / or a panel lower or secondary 32 of such an insulation block 30 of a tank 71 intended to receive an extremely cold liquid, such as LNG or LPG. Such a tank 71 can for example equip a ground tank, a floating barge or the like (such as an FSRU “Floating Storage Regasification Unit” or a FLNG “Floating Liquefied Natural Gas”) or even a ship, such as an LNG carrier. , transporting this energetic liquid between two ports.

[0121] The foam block according to the invention shown in FIG. 4 comprises a plurality of anchors 40, distributed over its various faces, upper 41, and lateral 42, 43. These anchors 40 are placed so as to be flush with the surface of said faces 41, 42, 43 of the foam block, without having a foam thickness (or not significant) covering it and / or protecting it from the outside.

[0122] Figure 5 shows, in cut-away view, an embodiment of such an insert 40. This insert 40 has a plate 44 extending in a plane. This plate 44 comprises a plurality of orifices 45 which consist of a mechanical anchoring means, in other words one of the two elements making it possible to fix, when engaged with an element of the thermal insulation block (not shown in the accompanying figures), the foam block in or in the thermal insulation block of the tank. The plate 44 also comprises a plurality of identical fixing studs 46 as well as a central fixing stud 47 having larger dimensions than that of the fixing studs 46. The function of these studs 46, 47 is to fix the best possible. 'insert 40 in the block of fiber foam according to the invention. The fixing studs 46 are ideally placed

circumferentially to form a circle near the periphery or the periphery of the insert 40. [0123] The insert 40 shown in FIG. 7 is advantageously placed on the transport belt 11, the pads 45, 46 then being directed upwards and the plate 44 resting on said strip 11.

[0124] Nevertheless, it is also possible to envisage placing these inserts 40 on the upper face 41 of the block, or even on the side faces 42, 43 as can be seen on the block shown in FIG. 4. In the latter case, we can advantageously provide for at least slightly pushing the pads 45, 46 into an adjacent / contiguous mat of fibers, before it is impregnated with the polymer foam.

[0125] Of course, one of these orifices 45 of the anchor 40 can as such be used to form the female part of the anchor, but it is also possible to provide that the anchor requires the use of a plurality of orifices 45. Furthermore, these orifices 45 consist of an anchoring solution but the invention is in no way limited to this embodiment and one or more anchors 40 of shape and mechanical characteristics can be considered. different.

[0126] With reference to FIG. 6, a cutaway view of an LNG carrier 70 shows a sealed and insulating tank 71 of generally prismatic shape mounted in the double hull 72 of the vessel. The wall of the vessel 71 comprises a primary waterproof barrier intended to be in contact with the LNG contained in the vessel, a secondary waterproof barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the vessel. primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier and the double shell 72.

[0127] In a manner known per se, the loading / unloading pipes 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a maritime or port terminal for transferring an LNG cargo from or to the tank. 71.

[0128] FIG. 6 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation. comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the pipes of

loading / unloading 73. The movable swivel arm 74 adapts to all sizes of LNG carriers. A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The underwater pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore installation 77 over a great distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

In order to generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps fitted to the shore installation 77 and / or pumps fitted to the loading and unloading station are used. 75.

[0130] As stated above, the use or application of

the object of the present invention, namely in this case the block of fiber-reinforced polyurethane / polyisocyanurate foam, is not intended to be reduced to a tank integrated into a supporting structure but it is also intended for tanks of type B and C of the IGC code in force on the date of filing of the present application, but also for future versions of this code except that these very substantial modifications apply to these tanks of type B and C, it being understood moreover that other types of tanks could, in this hypothesis of a modification of the IGC code, become applications

that can be envisaged for the block of fiber-reinforced PUR / PIR foam according to the present invention.

[0131] In the following, part of the experiments and tests carried out by the

Applicant to enable it to appreciate the object of the invention and its scope are presented, it being considered that other tests / experiments have been carried out and will be likely to be provided subsequently, if necessary / required. A polyurethane foam composition, integrating fibers in the form of mats, is used to demonstrate the invention, these fibers always appearing as long to continuous, more precisely the lengths of these fibers are exactly the same in the compositions according to the invention and those according to the state of the art. The Applicant has in particular tested the subject of the invention with so-called short fibers (as opposed to the definition given above for long to continuous fibers) or which are in the form of a fabric and the results obtained are equivalent or almost similar to those obtained with a mat of long to continuous fibers, as presented below.

[0133] Thus, in order to ensure that only the combination of particular characteristics of fiber density of the fiber reinforcements with the choice of a PUR foam having in particular a particular cream time, or adapted to the characteristics of said reinforcements of fibers, no other parameter of the preparation of a P IR foam block is modified or different, between the preparations in accordance with the invention and those in accordance with the state of the art. By way of non-exhaustive examples, mention may be made of the fact that the nucleation, the amounts of blowing agents, the reaction temperatures, nature and amounts of the mixture of chemical components, casting process, distance between the casting of the mixture of components chemicals and the DBL or the device allowing free expansion, where appropriate, are strictly identical in the cases according to the invention and in the cases according to the state of the art.

Of course, it has been chosen here to illustrate the invention using a PUR foam for the sake of clarity and conciseness, but equivalent or almost similar results have been obtained with PIR foams as well. as mixtures of PUR / PIR.

Likewise, the fiber foam preparations whose results are presented below use the free expansion technique, but the Applicant has shown that equivalent or almost similar results, with regard to fiber foams according to The invention and fiber foams according to the state of the art were obtained using a DBL. It is also understood that all the compositions tested below are considered to be isodensity, it being understood that this density parameter is involved in the assessment of performance in compressive strength.

[0137] For the compositions according to the state of the art, the characteristics of the fiber reinforcements and of the PUR foam are as follows:

[0138] [Tables 1]

For the compositions according to the invention, the characteristics of the fiber reinforcements and of the PUR foam are as follows:

[0140] [Tables 2]

[0141] It is noted that the cream time for the PUR foams used and

presented above is logically the same for the compositions according to the state of the technique and according to the invention, because the foam used is identical, whatever the case considered.

[0142] Following the performance of the tests, certain results are presented, in a simplified manner, below to illustrate the discoveries of the applicant, in the case where the fiber reinforcements are in the form of at least one mat. fiberglass.

[0143] [Tables 3]

It will be noted that the first composition (with 8 layers of U809 or U801 for a block 180 mm thick) in Table 3 consists of a composition in accordance with document FR 2882756. The results for such a composition according to this document are very significantly lower than those obtained with a composition according to the present invention (last composition of Table 3).

As can be seen with the results presented in the table above, on the three criteria considered to compare the fiber foams obtained, that in accordance with the invention exhibits very significantly better results than those of the fiber foams according to state of the art.

[0146] Furthermore, it should be noted that the fiber-reinforced PUR / PIR foams according to the invention do not exhibit any significant degradation of their property relating to (very low) thermal conductivity. Thus, by way of example, for a fiber-reinforced foam according to the invention, having a fiber density gradient of 1% by mass per centimeter (from the lower face towards the upper face of the block of fiber-reinforced foam), the following are obtained. following values of thermal conductivity:

[0147] [Tables 4]

[0148] Although the invention has been described in connection with several modes of

particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0150] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

[Claim 1] iBIoc of polyurethane / polyisocyanurate foam fiberized from a thermal insulation block (30) from a sealed and thermally insulating tank, the density of the block of fiber foam is between 30 and 300 kg / m ³ , the block of fiber-reinforced polyurethane / polyisocyanurate foam having an average fiber density Tf of between 1% and 60% by mass of fibers (10), preferably between 2% and 30%, and having a width L of at least ten centimeters, advantageously between 10 and 500 centimeters, and a thickness (E), from the lower face of said block to its upper face, of at least ten centimeters, advantageously between 10 and 100 centimeters, the foam block of

fibered polyurethane / polyisocyanurate being composed of cells

storing a gas, advantageously of low thermal conductivity, characterized in that the fiber density increases according to the thickness E, from the lower face of said block to its upper face (41), by a lower density range between 1% and 9.99% by mass of fibers (10) at a higher density range of between 10% and 35% by mass of fibers (10).

[Claim 2] A block of fiber-reinforced polyurethane / polyisocyanurate foam according to claim 1, wherein the density of the block of fiber-reinforced foam is between 50 and 250 kg / m ³ , preferably between 90 and 210 kg / m ³ .

[Claim 3] A fiber-reinforced polyurethane / polyisocyanurate foam block according to claim 1 or 2, wherein the increase in fiber density, relative to the total mass of the foam

polyurethane / polyisocyanurate fiber, corresponds to a gradient

increase of between 0.05% and 1.5% by weight of fibers per centimeter, preferably between 0.2% and 1.2% by weight of fibers per centimeter.

[Claim 4] A block of fiber-reinforced polyurethane / polyisocyanurate foam according to any one of the preceding claims, wherein at least 60%, preferably at least 80%, of said cells

storing a gas, advantageously of low thermal conductivity, have an elongated or stretched shape along an axis parallel to the axis of a thickness E of the block of fiber-reinforced polyurethane / polyisocyanurate foam.

[Claim 5] A polyurethane / polyisocyanurate fiber foam block according to any preceding claim, wherein the fibers consist of glass fiber or hemp fiber, preferably glass fiber.

[Claim 6] A fiber-reinforced polyurethane / polyisocyanurate foam block according to any preceding claim, wherein the fibers are long to continuous fibers.

[Claim 7] A fiber-reinforced polyurethane / polyisocyanurate foam block according to any preceding claim, in which the average fiber density Tf is between 2% and 25%, preferably 4% and 15%.

[Claim 8] A fiber-reinforced polyurethane / polyisocyanurate foam block according to any preceding claim, wherein the fiber density in the lower region is between 2% and 6% by weight of fibers (10) and the density of fibers. in the upper range is between 12% and 25% by weight of fibers (10).

[Claim 9] A block of fibered polyurethane / polyisocyanurate foam according to any one of the preceding claims, in which the lower face and / or the upper face (41), preferably the upper face (41), of said block has (s) anchors (40) adapted to engage with a means for engaging the thermal insulation block (30) in order to anchor the block of foam to said block (30), preferably said anchors (40) being made of a material different from foam or fibers.

[Claim 10] Polyurethane / polyisocyanurate fiber foam block according to any one of the preceding claims, comprising a flame retardant in a proportion of between 0.1% and 5% by mass, of the organophosphorus type, advantageously triethylphosphate (TEP) , tris (2-chloroiso-propyl) phosphate (TCPP), tris (1, 3- dichloroisopropyl) phosphate (TDCP), tris (2-chloroethyl) phosphate or tris (2,3-dibromopropyl) phosphate, or a mixture of these, or of the inorganic flame retardant type, advantageously red phosphorus, expandable graphite, an aluminum oxide hydrate, a trioxide antimony, arsenic oxide, ammonium polyphosphate, calcium sulphate or cyanuric acid derivatives, a mixture thereof.

[Claim 11] Tight and thermally insulating tank, said tank consisting of:

- a tank integrated into a supporting structure comprising a sealed and thermally insulating tank comprising at least one sealed metal membrane composed of a plurality of metal strakes or metal plates which may include corrugations and a thermally insulating solid (30) comprising at least one barrier thermally insulating adjacent to said membrane, or

- a type A, B or C tank according to the definition given by the IGC code comprising at least one thermally insulating block (30),

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

[Claim 12] A vessel (70) for the transport of a cold liquid product, the vessel comprising at least one hull (72) and a sealed and thermally insulating tank (71) according to claim 11 disposed in the hull or mounted on said hull. ship (70) when said tank is of type A, B or C according to the definition given by the IGC code.

[Claim 13] A transfer system for a cold liquid product, the

system comprising a ship (70) according to the preceding claim, insulated pipes (73, 76, 79, 81) arranged so as to connect the tank (71) installed in the hull of the ship to a floating or terrestrial storage unit (77 ) and a pump for driving a flow of cold liquid product through insulated pipelines from or to the floating or onshore storage unit to or from the vessel (70).

[Claim 14] A method of loading or unloading a ship (70) according to claim 12, wherein a cold liquid product is conveyed through insulated pipelines (73, 76, 79, 81) from or to a storage unit. floating or land (77) to or from the ship (71).

[Claim 15] Process for preparing a block of foam

polyurethane / polyisocyanurate fibred from a thermal insulation block with a sealed and thermally insulating tank according to one of claims 1 to 10, characterized in that it comprises the steps:

a) a mixture (12) of chemical components necessary for obtaining a polyurethane / polyisocyanurate foam, said components comprising reagents for obtaining polyurethane / polyisocyanurate,

optionally at least one reaction catalyst, optionally at least one emulsifier, and at least one blowing agent,

b) impregnation, by gravitational flow of the aforesaid mixture (12) of chemical components, of a plurality of fiber reinforcements (10), said fiber reinforcements being arranged in superimposed layers and having variable densities, an upper layer of reinforcement having a fiber density at least equal to that of the lower reinforcing layer, in which the fiber reinforcements (10) extend essentially in a direction perpendicular to the direction of said gravitational flow,

c) formation and expansion of the foam

polyurethane / polyisocyanurate fiber,

in which the expansion of the polyurethane / polyisocyanurate fiber foam is said to be free, either without the stress exerted by a volume of closed section, or

wherein the expansion of the fiber-reinforced polyurethane / polyisocyanurate foam is physically constrained by walls of a double strip laminator, preferably is physically constrained by the walls of a double strip laminator forming a tunnel of rectangular cross section with a distance between the walls disposed laterally equal to L and a distance between the walls disposed horizontally equal to (E), thus enclosing the expanding fibered foam so as to obtain the aforesaid block of polyurethane / polyisocyanurate fiber foam.