FR2938267A1 - Use of an adhesive composition made of polyurethane bicomponent in cryogenic application, preferably methane tanker carrying liquefied gases - Google Patents

Abstract

Use of an adhesive composition (I) made of polyurethane bicomponent having a shearing strength measured according to ISO 4587 which is greater than 10 MPa over the entire temperature of -170[deg] to 40[deg] C, in cryogenic application, is claimed. An independent claim is included for adhesive composition obtained by reaction between a resin as part A and a hardener as part B, where the part A is represented by the mixture comprising the ingredients: (a) 20-60 wt.% of part A, preferably 23-45 wt.% of a polyol comprising polyether polyol (a1), polyester polyols (a2), unsaturated polyols (a3) or thermoplastic polyurethanes having hydroxyl endings (a4), each component (a1)-(a4) having an average molecular mass of 200-9000 g/mole and hydroxyl (OH) functionality of 2-4.6, where the polyol (a) of the part A comprises at least one thermoplastic polyurethane prepolymer having OH terminations (a4) comprising aromatic and/or aliphatic polyurethane pre polymers; (b) 0.4-3 wt.% of the part A, preferably 0.5-1.5 wt.% of at least one threshold comprising amino group or primary or secondary polyamines; (c) 2-10 wt.% of the part A, preferably 4-8 wt.% of at least a long chain comprising 2-10C diol group; (d) 22-70 wt.% of part A, preferably 35-65 wt.% of inorganic fillers; (e) 2-6 wt.% of part A, preferably 3-4 wt.% of at least one additive comprising wetting agents, defoamers, dispersants, dyes, thickeners or thinners; (f) 0-0.05 wt.% of part B, preferably 0.01-0.04 wt.% of a heat inducing crosslinking catalyst, and the part B is represented by the composition comprising the ingredients (g) 75-100 wt.% of the part B, preferably 85-90 wt.% of at least one polyurethane prepolymer having isocyanate (NCO) endings of average molecular mass of 840-2100 g/mole and NCO functionality of 2-4, (h) 0-20 wt.% of part B, preferably 5-15 wt.% of inorganic fillers, (i) 0-5 wt.% of part B, preferably 1-3 wt.% of at least one additive comprising thickeners or thinners and the ratio of NCO (meq/g) groups of the part B on the sum of reactive functions OH (meq/g) and NH (meq/g) of the part A is 0.90-1.20, preferably 1-1.10.

Description

USE OF AN ADHESIVE COMPOSITION BASED ON POLYURETHANE FOR CRYOGENIC APPLICATION

Field of the invention

The present invention relates to the use of a bi-component polyurethane structural adhesive composition (PU2K) in cryogenic applications, in particular in LNG carriers carrying liquefied gases. The present invention thus relates to the use of an adhesive composition having a shear strength that is greater than 10 MPa measured according to ISO 4587 over the entire temperature range of + 40 ° C to -170 ° C. In particular, the adhesive composition serves as an adhesion element between two substrates to form a multilayer structure suitable for sealing against gases and liquids in the entire temperature range from + 40 ° C. to - 170 ° C. Technological Background of the Invention

In a tanker, the tanks in which the liquid methane is stored, are made of different materials and barriers that ensure sealing. For storage and transport of liquid methane at a temperature of -163 ° C, excellent insulation is essential. In addition a reduction of the thickness of insulation is desired to maximize the volume transported.

In the new generations of LNG tankers, the sealed and insulating tanks integrated in a supporting structure, in particular of ship, comprise two successive sealing barriers, a primary barrier in contact with the product contained in the tank and another barrier, called secondary, disposed between the primary barrier and the carrier structure, these two sealing barriers being alternated with two thermally insulating barriers. The secondary barrier is intended to temporarily contain any liquid cargo leak that is likely to occur through the primary barrier. Thus, in the event of damage (flooding on the sea side or liquefied gas side), the containment barrier must ensure liquefied gas sealing for at least 15 days (maximum time to reach a removal station) and therefore withstand prolonged contact. with seawater or liquefied gas (-163 ° C). To achieve the performance required by the international gas code, this double barrier or membrane is currently constituted by a primary barrier, in R'Brevets .265002 6562-081029-text deposit.doc contact with liquefied gas LNG, currently INO or INVAR (New SC 1 design) and a secondary containment barrier in INVAR (NO96 technology) or more widely now TRIPLEX for SC1 and MARK III technologies). This barrier, in normal operation is permanently at a temperature between -100 and -120 ° C. Today these TRIPLEX membranes are mainly manufactured by HUTCHINSON for flexible TRIPLEX membranes and by HANKUK Carbon for rigid TRIPLEX membranes. TRIPLEX membranes are glass / aluminum / glass fabric composite membranes made of vulcanised rubber for flexible TRIPLEX and epoxy polyamide for rigid TRIPLEX. The construction of the secondary barrier is a sensitive step, especially for the CS1 and MARK III technologies where the assembly of the constituent elements of the secondary barrier of the vessel is done by gluing. According to this method, rigid TRIPLEX (RSB Rigid Secondary Barrier) membrane parts joined to fiber reinforced polyurethane foam boards are joined together by strips of flexible TRIPLEX (FSB Flexible Secondary Barrier). The assembly of this secondary barrier is carried out mainly in manual application with a semi rigid Epoxy adhesive. Indeed, for example, WO 2007/52961 (see 30 and Figure ref 40) describes methods of connection between the secondary barriers and the primary barrier insulating panels using an adhesive epoxy adhesive. Furthermore, in the field of LNG carriers, FR 2822814 describes an automatic device for bonding a strip in which the connection between these two types of membrane is effected by an epoxy adhesive. The document mentions that this connection can also be performed by a glue called polyurethane mono-component (PU 1 K). Currently, the adhesives mainly used in cryogenic applications and mainly in the sealing barriers of LNG carriers, are epoxy type adhesives but their adhesion performance require improvements and moreover they have the disadvantage of lack of flexibility. SUMMARY OF THE INVENTION The object of the present invention is to provide a solution adapted to assembly constraints such as adhesion and structural properties, and to the following: sealing in cryogenic industrial applications, especially in the entire temperature range of -170 ° C to + 40 ° C. The Applicant has now surprisingly found that polyurethane adhesives improve the performance of the structures in which they are integrated, including flexibility and adhesion in cryogenic applications. Also, the invention proposes the use of a bi-component polyurethane adhesive composition (PU2K) having a shear strength greater than 10 MPa measured according to ISO 4587 over the entire temperature range from -170 ° C to + 40 ° C. Preferably this adhesive composition serves as an adhesion element between two substrates to form a multilayer structure adapted to seal against gases and liquids over the entire temperature range from -170 ° C to + 40 ° C. This adhesive composition based on polyurethane (PU) is more particularly useful in the manufacture of sealed and thermally insulating vessels integrated into a supporting structure, in particular the hull of a vessel intended for the sea transport of liquefied gases and, in particular , for the transport of liquefied natural gas (LNG) with a high methane content. This polyurethane (PU) adhesive composition may also find utility in the manufacture of aeronautical parts exposed to particularly low temperatures during flight. According to one preferred embodiment, the adhesive composition is obtained by reaction between a part A called resin and a part B called hardener, Part A being represented by the mixture comprising the ingredients: a) at least one polyol chosen from polyol polyethers (al) Polyester polyols (a2), unsaturated polyols (a3), hydroxyl-terminated thermoplastic polyurethane prepolymers (a4), each of components a1 to a4 having an average molecular weight in the range of from 200 to 9000 g / mol and functionality. OH between 2 and 4.6; b) at least one threshold agent selected from the group of primary or secondary amines or polyamines; c) optionally a chain extender selected from the group of diols from C2 to Cl 0; (d) inorganic fillers; A) at least one additive selected from the group of wetting agents, defoamers, dispersants, dyes, thickeners, fluxing agents; f) optionally a thermal release crosslinking catalyst; Part B being represented by the composition comprising the ingredients: g) at least one NCO-terminated polyurethane prepolymer with an average molecular weight of between 840 and 2100 g / mol and with an NCO functionality of between 2 and 4; (h) inorganic fillers; i) at least one additive selected from the group of thickeners, fluidifying agents. According to a preferred embodiment, the proportions of the various ingredients are as follows: a) the polyol represents from 20 to 60% by weight of the part A, preferably 23 to 45%; b) the threshold agent is 0.4 to 3% by weight of the part A, preferably 0.5 to 1.5%; c) the chain extender represents from 0 to 10% by weight of the part A, preferably 4 to 8%; d) the inorganic fillers represent from 22 to 70% by weight of the part A, preferably from 35 to 65%; the inorganic fillers are distributed between the molecular sieve (2 to 15% by weight in Part A, preferably 10 to 15%) and the mineral fillers (20 to 65% by weight of Part A, preferably 25 to 50% by weight). %). e) the additives represent from 2 to 6% by weight of the part A, preferably 3 to 4%; f) the catalyst represents from 0 to 0.05% by weight of the part A, preferably 0.01 to 0.04%; g) the NCO prepolymer represents 75 to 100% by weight of the B part, preferably 85 to 90%; h) the inorganic fillers represent from 0 to 20% by weight of the B part, preferably 5 to 15%; i) the additives represent from 0 to 5% by weight of the part B, preferably 1 to 3%; and the ratio of the NCO functions (meq / g) of the part B to the sum of the reactive functional groups OH (meq / g) and NH (meq / g) of the part A ranging from 0.90 to 1.20 preferably from 1.00 to 1.10. According to a preferred embodiment, the polyol a) of part A is at least one OH-terminated thermoplastic polyurethane prepolymer (a4) chosen from aliphatic and aromatic polyurethane prepolymers. , and mixtures of these compounds.

According to one preferred embodiment, the adhesive composition is obtained by reaction of part A with part B in a volume ratio A / B ranging from about 0.85 to about 1.15, preferably in a ratio of about 1, and present an initial viscosity measured according to ISO 2555, between 27 and 120 Pa.s, preferably between 45 and 110 Pa.s or 65 to 100 Pa.s.

In a preferred embodiment, compound b) is represented by piperazine and its derivatives. According to a preferred embodiment, the compound a) comprises at least one hydrophobic nature vegetable polyol, preferably represented by castor oil and the compound d) comprises at least one inorganic filler coated with a hydrophobic coating, preferably with a sieve molecular. In a preferred embodiment, the adhesive composition has an open time ranging from 90 minutes to 150 minutes, the open time being the time from which the shear strength value measured according to ISO 4587 has lost 20% of its initial value.

In a preferred embodiment, the polyurethane adhesive composition is located between a flexible membrane (FSB) and a rigid membrane (RSB) to form the multilayer structure. According to a preferred embodiment the use comprises the application of the adhesive composition, after extrusion, manually or automatically between at least one strip of a rigid membrane and at least one strip of a flexible membrane with a thickness of between 0 , 2 and 5 mm, under climatic conditions of high temperature T and relative humidity RH, preferably T greater than 25 ° C and HR greater than 55%, preferably T between 28 and 40 ° C, and RH between 60 and 85%.

According to one preferred embodiment, the multilayer structure represents the secondary sealing barrier of a tank integrated in a supporting structure, such as the hull of a vessel intended for the sea transport of liquefied gas. According to another object, the invention relates to a particular adhesive composition obtained by reaction between a part A called resin and a part B called hardener, Part A being represented by the mixture comprising the ingredients: R: \ Patents \ 26500 \ 26562 A) from 20 to 60% by weight of the part A, preferably from 23 to 45% of at least one polyol chosen from polyol polyethers (a1), polyester polyols (a2), polyesters and polyols; unsaturated polyols (a3), hydroxyl-terminated thermoplastic polyurethanes (a4), each of components al to a4 having an average molecular weight of from 200 to 9000 g / mol and OH functionality of from 2 to 4.6; polyol a) of part A comprising at least one OH-terminated thermoplastic polyurethane prepolymer (a4) chosen from aliphatic and aromatic polyurethane prepolymers, and mixtures of these compounds; b) from 0.4 to 3% by weight of the portion A, preferably 0.5 to 1.5% of at least one threshold agent selected from the group of primary or secondary amines or polyamines; c) from 0 to 10% by weight of the portion A, preferably from 4 to 8% of at least one chain extender selected from the group of diols from C2 to c Io; d) from 22 to 70% by weight of part A, preferably 35 to 65% of inorganic fillers with preferably inorganic fillers distributed between the molecular sieve (2 to 15% by weight in part A, preferably 10 to 15%) and the mineral fillers (20 to 65% by weight of the part A, preferably 25 to 50%). e) from 2 to 6% by weight of the part A, preferably 3 to 4% of at least one additive chosen from the group of wetting agents, defoamers, dispersants, dyes, thickening agents, fluidifying agents ; f) from 0 to 0.05% by weight of the A part, preferably 0.01 to 0.04% of a thermal release crosslinking catalyst; Part B being represented by the composition comprising the ingredients: g) from 75 to 100% by weight of the B part, preferably 85 to 90% of at least one NCO-terminated polyurethane prepolymer having an average molecular weight of and 2100 g / mol and NCO functionality of 2 to 4; h) from 0 to 20% by weight of the B part, preferably 5 to 15% of inorganic fillers; i) from 0 to 5% by weight of the B part, preferably 1 to 3% of at least one additive selected from the group of thickeners, fluidifying agents; and the ratio of the NCO functions (meq / g) of the part B to the sum of the reactive functional groups OH (meq / g) and NH (meq / g) of the part A ranging from 0.90 to 1.20 preferably from 1.00 to 1.10. The preferred adhesive composition is that in which the polyurethane prepolymer (a4) is obtained by polyaddition of at least one polyol of the type (a) to (a) and (b). at least one polyisocyanate in amounts such that the NCO / OH ratio is between 0.1 and 0.5. Figure 1 shows the composite FSB / RSB assembly in the shear strength test.

Figure 2 shows the description of the manual application. Figure 3 shows the preparation of H2 specimens. Figure 4 shows the sectional diagram of a portion of the sealed tank. DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION In the field of cryogenic applications and in particular that of the LNG carriers, the adhesive products used which make it possible to establish the connection between the primary and secondary barriers of a vessel once in place, must meet the requirements of the International Gas Code required for LNG carriers. The following basic properties are therefore sought for these adhesives: • good adhesion properties (peel and traction) on FSB / RSB between -170 ° C and 40 ° C (temperature of liquid methane at atmospheric pressure: -163 ° C); • good wettability properties to ensure sealing properties; • good flexibility properties to withstand stresses at temperatures up to -170 ° C; • a consistency that makes them pumpable. The invention thus proposes the use of a two-component polyurethane adhesive composition (PU2K) having a shear strength greater than 10 MPa measured according to ISO 4587 throughout the temperature range from -170 ° C to + 40 ° C and able to seal against gases and liquids as an adhesive element between two substrates to form a multilayer structure. Thus, the adhesive compositions used in the invention basically have the properties normally required for bonding adhesives between the primary and secondary barriers of a sealed LNG tank ie adhesion, flexibility, wettability, pumpability (eg gear pump), storage stability. In addition, the adhesive compositions used in the invention also have the following properties: • a structural bonding on difficult substrates (ex: INVAR, FSB, RSB ...) between -170 ° C and 40 ° C (temperature of liquid methane at atmospheric pressure: -163 ° C); • good flexibility to withstand the typical constraints of cryogenic application; • a good applicability, that is to say having enough threshold to avoid the phenomena of run-off (application in vertical positions and on the ceiling) but also with a consistency adapted to a manual removal (to make easily with the spatula films uniforms up to several mm thick). • low sensitivity to ambient climate conditions (eg no foaming at 30 ° C, 70% RH); • long open time with potentially increased hot responsiveness to meet productivity requirements; • the absence of bubbles larger than 12 mm in the glue joint, after peeling of the assembled supports; The adhesive compositions used in the invention optionally contain a thermal release catalyst to accelerate the crosslinking hot and increase productivity. Description of the Composition The composition used in the invention is obtained by reaction between a part A called resin and a part B called hardener; Part A is represented by the composition comprising the following ingredients: a) at least one polyol chosen from polyol polyethers (a1), polyester polyols (a2), unsaturated polyols (a3), hydroxyl-terminated thermoplastic polyurethanes (a4) ), each of the components al to a4 having an average molecular weight of between 200 and 9000 g / mol and an OH functionality of between 2 and 4.6; b) at least one threshold agent selected from the group of primary or secondary amines or polyamines; (C) optionally a chain extender selected from the group of diols C 2 -C 10; (d) inorganic fillers; e) at least one additive selected from the group of wetting agents, defoamers, dispersants, dyes, thickeners, fluidifying agents; f) optionally a thermal release crosslinking catalyst; Part B is represented by the composition comprising the following ingredients: g) at least one NCO-terminated polyurethane prepolymer having an average molecular weight of from 840 to 2100 g / mol and an NCO functionality of from 2 to 4; (h) inorganic fillers; I) at least one additive selected from the group of thickening agents, fluidizing agents. PART A (a) polyols. The polyether polyols are generally selected from aliphatic and aromatic polyether polyols and mixtures thereof. Preferably, their average molecular mass is between 200 and 9000 g / mol and their hydroxyl functionality is between 2 and 4.6. As examples of aliphatic polyether polyols, mention may be made of: - oxyalkylated derivatives of diols (for example monoethylene glycol, monopropylene glycol) such as polypropylene glycols, - oxyalkylated derivatives of triols (for example glycerol, trimethylolpropane or hexane-1,2,6-triol) such as copolymers of ethylene oxide and propylene oxide and polymers of ethylene oxide, propylene oxide or butylene oxide, polytetramethylene glycols, examples of aromatic polyether polyols include oxyalkylated derivatives of diphenyls such as oxyethylenated or oxypropylenated derivatives of 4,4'-bisphenol F and Bisphenol A. R: ABrevets`26500'2 6562-0 8 1029-text dep Preferably, the oxypropyl derivatives of diols and of triols, and the polytetramethylene glycols are used, mention may be made in particular of VORANOLs from DOW or TERATHANEs from INVISTA (a2). Polyester polyols are generally chosen from the following: aliphatic and aromatic polyester polyols, and mixtures of these compounds. Preferably, their average molecular weight is between 250 and 7000 and their hydroxyl functionality is between 2 and 4. By way of examples, mention may be made of: polyol polyols resulting from the condensation of aliphatic (linear branched or cyclic) polyols ) or aromatics such as ethanediol, 1,2-propanediol, 1,3-propanediol, glycerol, trimethylolpropane, 1,6-hexanediol, 1,2,6-hexanetriol, butenediol, sucrose , glucose, sorbitol, pentaerythritol, mannitol, triethanolamine, N-methyldiethanolamine and mixtures of these compounds with a polycarboxylic acid or its ester or anhydride derivative such as 1,6-hexanedioic acid, the acid dodecanedioic acid, azelaic acid, sebacic acid, adipic acid, 1,18-octadecanedioic acid, phthalic acid, succinic acid and mixtures of these acids, an unsaturated anhydride such as anhydride maleic or phthalic, or a lactone such than caprolactone; polyesters polyols of natural origin such as castor oil. Preferably, the polyester polyols resulting from the condensation of ethanediol, 1,3-propanediol and / or 1,6-hexanediol with adipic acid and / or phthalic acid, polycaprolactones and polyesters are used. Castor oil. These include DYNACOL from EVONIK, CAPA from SOLVAY and castor oil from NIDERA. a3) The unsaturated polyols are generally chosen from polyols and mixtures of polyols preferably having a molecular mass of between 1200 and 3000. By way of examples, mention may be made of polybutadiene and hydroxyl-terminated polyisoprene (for example PolyBD R45 HT from Arkema). The above-mentioned polyols a 1) to a 3) can also be used in admixture with other hydroxyl compounds such as OH-terminated thermoplastic polyurethanes (a4) in place of the aforementioned conventional polyols. a4) OH-terminated thermoplastic polyurethane prepolymers are generally selected from aliphatic and aromatic polyurethane prepolymers, and mixtures of these compounds. Preferably, their average molecular weight is between 250 and 7000 and their hydroxyl functionality is between 2 and 4. The polyurethane prepolymer (a4) is obtained by polyaddition. at least one polyol of type al) to a3) and at least one polyisocyanate (d) in amounts such that the NCO / OH ratio is between 0.1 and 0.5. The nature of the polyurethane prepolymer influences the rise in cohesion. In this regard, the OH-terminated polyurethane prepolymers obtained by reacting a mixture of polyester polyols (a2, a3) of functionality 2 to 3 and at least one aromatic polyisocyanate of functionality 2 to 2.5 are preferred.

By way of examples, mention may be made of the polyaddition products of the polyether polyols (a1) and / or polyester polyols (a2 or a3) previously mentioned with a polyisocyanate (d) generally chosen from the aliphatic, cycloaliphatic or aromatic polyisocyanates well known in the art. those skilled in the art, as well as mixtures of these compounds. Examples of aliphatic polyisocyanates are hexamethylene diisocyanate (HMDI), ethylenediisocyanate, ethylidenediisocyanate, propylene diisocyanate, butylene diisocyanate, dichlorohexamethylene diisocyanate, furfurylene diisocyanate, mixtures of these compounds and their oligomers.

Examples of cycloaliphatic polyisocyanates that may be mentioned include isophorone diisocyanate (IPDI), cyclopentylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, cyclohexylene-1,2-diisocyanate, and mixtures of these. compounds and their oligomers. By way of examples of aromatic polyisocyanates, mention may be made of diphenylmethane diisocyanate, in particular 4,4'-diphenylmethane diisocyanate (MDI), 2,4'-diphenylmethane diisocyanate and 2,2'-diphenylmethane diisocyanate, toluene diisocyanate, in particular 2, 4-toluenediisocyanate (TDI) and 2,6-toluenediisocyanate, 2,2-diphenylpropane-4,4'-diisocyanate, p-phenylenediisocyanate, m-phenylene diisocyanate, xylene diisocyanate, 1,4-naphthalene diisocyanate, , 5-Naphthylenediisocyanate, azobenzene-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, 1-chlorobenzene-2,4-diisocyanate, mixtures of these compounds and their oligomers. Preferably, diisocyanates, and more particularly MI) I, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, TDI, are used alone or in combination. , 2,6-toluenediisocyanate, HMDI, IPDI and their oligomers. Dow Jones ISONATE M 143 is preferred here. b) The threshold agent is selected from the group of amines or polyamines, primary or secondary. These amines, reacting rapidly with the isocyanates of the hardener, produce polyureas. The polyureas give rise to very strong hydrogen bonds which significantly increase the viscosity of the mixture, thus reducing sagging.

The amines are chosen from ethylene diamine, propylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, isophorone diamine, dicyclohexylmethane diamine, cyclohexane diamine, piperazine, amino ethyl piperazine, 2-methylpentamethylene diamine, 1,12-dodecane diamine, bishexamethylenediamine, dimethylethylenediamine, diethylenediamine, dimethylpropylenediamine, diethylpropylene diamine, pentaethylenehexamine, diethylene triamine, hydrazine, xylylene diamine, m-phenylene diamine, p-phenylenediamine, 4,4'-methylene dianiline, 4,4 ' -diaminodiphenyl sulfone, piperazine, 2,6-diaminopyridine, 4,41-methylene bis (orthochloroaniline), diethyltoluene diamine, primary or secondary polyetheramines of molar mass between 100-10000 g / mol and having a functionality of between 2 and 3 , such as the Jeffamine family from Huntsman. When no threshold agent is added the mixture is too flowing and the viscosity too low (26 Pa. $) For a correct application of the glue. The incorporation of a threshold agent belonging to the family of amines or polyamines into the resin has an impact on the initial viscosity of the adhesive composition and its sagging capacity at the time of application to the first substrate. Piperazine or JEFFAMINE T 403 is preferably used, which makes it possible to reduce or eliminate the phenomena of sagging. It may be necessary to use a solvent to solubilize the threshold agent b), especially piperazine. This solvent is chosen from polyether polyols of functionality between 2 and 3 of average molecular weight between 400 and 800 such as VORANOL CP 450 from DOW. c) Optionally, a chain extender is used, chosen in a non-limiting manner from the group of primary and / or secondary linear diols, cyclic or branched. saturated or unsaturated C2 to C10. The diols are selected from ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,6-hexanediol, 2-butene-1,4- diol, 2-ethyl-1,3-hexanediol and 2-methyl-1,3-propanediol and 1,6-cyclohexanediol. d) The inorganic fillers are chosen from the group of mineral fillers d1 such as calcium carbonates, talcs, kaolins and the group d2 of molecular sieves of synthetic zeolites type. These include the CRAIE 200 TB from OMYA, SOCAL 312 from SOLVAY and UOP L POWDER from UOP.

These charges are advantageously less than 200 microns, preferably less than 100 microns to give the mixture of Part A the property of being pumpable (gear pump). e) other additives. Part A may furthermore comprise, according to the invention, additives e) such as a wetting and / or dispersing additive such as an ethoxylated fatty alcohol or a carboxylic acid salt of polyamidoamine (ANTI-TERRA 204 from BYK ), an antifoam agent (s) based on a non-aqueous solution of a polysiloxane (BYK 080 from BYK), pigments or organic and / or inorganic dyes such as carbon black or Carbidex blue, rheological modifiers in pulverulent form of fumed silica type (AEROSIL R 202 from EVONIK DEGUSSA) or waxes (THIXATROL ST from RHEOX / ELEMENTIS or Crayvallac Antisettle CVP from Cray-Valley), plasticizers of the Mono and bis type (xylyl) xylene (JARYSOL) 0de from Arkema). Advantageously, the use of hydrophobic treated fillers and additives helps to reduce the sensitivity of the adhesives to extreme weather conditions and therefore to foaming. Incorporation of a higher molecular sieve concentration (10 to 15% by weight of Part A) allows water to be trapped before it reacts with the isocyanates and to eliminate foaming. f) A thermally triggered crosslinking catalyst, preferably a blocked tertiary amine, may optionally be present in part A. Incorporation of a catalyst f) makes it possible to maintain a long open time at ambient temperature while accelerating very strongly the heat crosslinking, and thus increase the

A: ABrevetsv26500 \ 2 6562-08 1 02 9-text deposit.doc productivity. Particularly preferred catalyst is 1,8-diazabicyclo [5.4.0] undec-7-ene or DBU from AIR PRODUCTS. PART B. g) NCO-terminated polyurethane prepolymers g) are generally selected from aliphatic and aromatic polyurethane prepolymers, and mixtures of these compounds. Preferably, their average molecular weight is between 840 and 2100, their NCO functionality being between 2 and 4, with NCO contents of between 8 and 20% by weight and preferably between 11 and 17%.

The NCO-terminated polyurethane pre-polymer (g) is obtained by polyaddition of at least one polyol chosen from the polyols (al) to (a) mentioned above in Part A and from at least one polyisocyanate (d) mentioned above. in part A in amounts such that the NCO / OH ratio is between 3 and 5. The nature of the polyurethane pre-polymer g) influences the reactivity of A + B.

In this regard, the NCO-terminated polyurethane prepolymers obtained by reacting a mixture of polyether polyols (a1) of functionality 2 to 3 and at least one aromatic polyisocyanate of functionality 2 to 2.5 are preferred. h) The inorganic fillers h) are chosen from the group of mineral fillers such as calcium carbonates, talcs, kaolins and the group of molecular sieves of synthetic zeolites type. These include the CRAIE 200 TB from OMYA, SOCAL 312 from SOLVAY and UOP L POWDER from UOP. These charges are advantageously less than 200 microns, preferably less than 100 microns to give the mixture of part B the property of being pumpable (gear pump). i) other additives. Part B may furthermore comprise additives i) such as organic and / or inorganic pigments or dyes, rheological modifiers in pulverulent form, preferably of pyrogenic silica type (AEROSIL R 202 from EVONIK DEGUSSA).

Quantitative distribution of ingredients in the composition. According to a preferred embodiment of the use of the cryogenic adhesive composition: a) the polyol represents from 20 to 60% by weight of the part A, preferably 23% by weight; 45%; b) the threshold agent is 0.4 to 3% by weight of the part A, preferably 0.5 to 1.5%; c) the chain extender represents from 0 to 10% by weight of the part A, preferably 4 to 8%; d) the inorganic fillers represent from 22 to 70% by weight of the part A, preferably from 35 to 65%; the inorganic fillers are distributed between 2 to 15% by weight of Part A, preferably 10 to 15% of molecular sieve, and from 20 to 65% by weight of Part A, preferably from 25 to 50% of mineral fillers. . e) the additives represent from 2 to 6% by weight of the part A, preferably 3 to 4%; f) the catalyst is 0 to 0.05% by weight of the B part, preferably 0.01 to 0.04%; g) the NCO prepolymer represents 75 to 100% by weight of the B part, preferably 85 to 90%; h) the inorganic fillers represent from 0 to 20% by weight of the B part, preferably 5 to 15%; i) the additives represent 0 to 5% by weight of part B, preferably 1 to 3%; and the ratio of the NCO functions (meq / g) of the part B to the sum of the reactive functional groups OH (meq / g) and NH (meq / g) of the part A ranging from 0.90 to 1.20 preferably from 1.00 to 1.10. According to another object the invention relates to a particular adhesive composition that meets all of the targeted properties defined above and which is obtained by reaction between a part A called resin and a part B called hardener, Part A being represented by the mixture comprising the ingredients: a) from 20 to 60% by weight of part A, preferably from 23 to 45% of at least one polyol chosen from polyol polyethers (a1), polyester polyols (a2) and unsaturated polyols (a3), the hydroxyl-terminated thermoplastic polyurethanes (a4), each of components a1 to A4 having a mean molecular weight of between 200 and 9000 g / mol and of functionality OH between 2 and 4.6; polyol a) of part A comprising at least one OH-terminated thermoplastic polyurethane prepolymer (a4) chosen from aliphatic and aromatic polyurethane prepolymers, and mixtures of these compounds; b) from 0.4 to 3% by weight of the part A, preferably 0.5 to 1.5% of at least one threshold agent selected from the group of amines or polyamines, primary or secondary; c) from 0 to 10% by weight of the portion A, preferably from 4 to 8% of at least one chain extender selected from the group of C2 to C10 diols; d) from 22 to 70% by weight of the part A, preferably 35 to 65% of inorganic fillers; the inorganic fillers are distributed between the molecular sieve (2 to 15% by weight in Part A, preferably 10 to 15%) and the mineral fillers (20 to 65% by weight of Part A, preferably 25 to 50% by weight). %). e) from 2 to 6% by weight of the part A, preferably 3 to 4% of at least one additive chosen from the group of wetting agents, defoamers, dispersants, dyes, thickening agents, fluidifying agents ; f) from 0 to 0.05% by weight of the B part, preferably 0.01 to 0.04% of a thermal release crosslinking catalyst; Part B being represented by the composition comprising the ingredients: g) from 75 to 100% by weight of the B part, preferably 85 to 90% of at least one NCO-terminated polyurethane prepolymer having an average molecular weight of and 2100 g / mol and NCO functionality of 2 to 4; h) from 0 to 20% by weight of the B part, preferably 5 to 15% of inorganic fillers; i) from 0 to 5% by weight of the B part, preferably 1 to 3% of at least one additive selected from the group of thickeners, fluidifying agents; and the ratio of the NCO functions (meq / g) of the part B to the sum of the reactive functional groups OH (meq / g) and NH (meq / g) of the part A ranging from 0.90 to 1.20 preferably from 1.00 to 1.10. Preferably in this adhesive composition, the polyurethane prepolymer (a4) is obtained by polyaddition of at least one polyol of type a1) to a3) and at least one polyisocyanate in amounts such that the NCO / OH ratio is between 0.1 and 0.5.

Process for the preparation of adhesive compositions Each part A or B is prepared separately. Part A is prepared by mixing the various ingredients a) to f) under vacuum to degas the medium between 23 ° C and 70 ° C. Part B is prepared in a first step by reaction under vacuum at a temperature between 70 ° C and 110 ° C between a polyol a) and a polyisocyanate (jj) until the target NCO% (from 8% to 20%) in the isocyanate pre-polymer g). Then in a second step after cooling to about 20 ° C, the prepolymer g) is mixed with the other ingredients h) to i). The resin and the associated hardener are packaged in a double-layer. The glue is dispensed using a double-barrel gun. A homogeneous mixture of the two components is obtained by attaching a static mixer to the two-cartridge. The adhesive composition is obtained according to a method known to those skilled in the art by reaction of the part A with the part B in an NCO / OH + NH ratio ranging from about 0.90 to 1.20, preferably between 1.00 and 1.10 so that the volume ratio of the parts A and B is preferably close to 1. The NCO / OH + NH ratio is defined as the ratio of the NCO functions (meq / g) of the hardener B on the sum of the reactive functions OH (meq / g) and NH (meq / g) of the resin A.

The reactivity of A with B can be easily controlled by the addition of catalyst f) in part A and / or by the nature of the polyisocyanates (j) used in part B. It is notably observed that the reactivities are lower in the presence of LUPRANAT MIPI (Examples C5 to C9) with respect to the presence of ISONATE M143 alone (examples CI to C4) due to the presence of the 2,2 'isomer.

Characteristics of the adhesive composition. Resins A or hardeners B are characterized by: - their color: visual observation; their density: measured with a 50 ml pycnometer on products at 23 ° C .; - their viscosity: measured with a Brookfield RVT viscometer (ISO 2555 standard), needle 7, rotational speed of 20 rpm, on products at 23 ° C. VS ; - their tendency to sediment (loaded products) characterized by the% of serum. A bottle containing 500 ml of resin or hardener is stored in an oven at 40 ° C for one month. The% δ of serum corresponds to the amount of supernatant recovered after 1 month of storage at 40 ° C normalized by the total amount of product initially introduced. The viscosity of the resin and hardener (between 20 and 100 Pa.), Their low density (between 1.0 to 1.7) and the size of the fillers used (less than 200 m and preferably less than 100 m) make all these resins or hardeners products perfectly pumpable by gear pump. The products also have excellent stability since after prolonged storage at 40 ° C no significant sedimentation is observed (% serum <1% and only in the case of resins which unlike hardeners are loaded). This feature makes them usable with dosing machines. Sedimentation is controlled by varying the size of the charges such as MIKHART C (max 50 m) and / or incorporating thickeners such as Thixatrol ST or Aerosil R202. Structural Properties of Adhesive Compositions Shear strength. The bicomponent polyurethane adhesive compositions provide structural bonding over a wide temperature range of -170 ° C to 40 ° C. They are distinguished from non-structural polyurethane adhesives which may be used in other places where it is not necessary to provide good cryogenic performance. More particularly, the adhesive compositions have a shear strength greater than 10 MPa measured according to ISO 4587 for thicknesses of 0.2 to 4.0 mm over the entire temperature range of -170 ° C to 40 ° C. A) The shear tensile strength at 23 ° C. of the adhesive deposited between two INVAR / INVAR stainless steel metal supports is measured. R: Abre. ands \ 2 6500 26562-081029-text ptit.doc Method. The INVAR test pieces (dimensions: 25 mm wide x 100 mm long x 1.5 mm thick) are sanded in the width direction with abrasive paper P40 (roughness 10-15 microns), degreased with heptane and dried. min.

The adhesive previously conditioned at 23 ° C. in a double-layer film is deposited on one of the frosted ends of one of the INVAR test pieces on a surface of 25 × 12.5 mm 2, thickness: 0.8 mm (adjustment with the shims). The other test piece is then placed in the axis of the first on the frosted face and the assembly is strongly pressed (for 6 test pieces: dry weight> 4.5 kg).

The whole is kept 2 hours in a ventilated oven regulated at 60 ° C. The assembly is then maintained under pressure for a minimum of 24 hours at 23 ° C. The tensile test is carried out after 7 days of crosslinking at 23 ° C. using a dynamometer (INSTRON inodel 1185) at 10 mm / min. A holding device is fitted on the jaws of the device to prevent buckling of the specimens.

The force at break is measured. The shear strength at 23 ° C is calculated by normalizing this force by the actual glue joint area. All the exemplified compositions exhibit an INVAR / INVAR shear tensile strength greater than 10 MPa, characteristic of structural assemblies. b) The shear strength of the adhesive deposited between two FSB / RSB supports was measured at 170 ° C. The shear test is carried out at -170 ° C. and at a pulling speed of 1.3 mm / min on a mixed FSB / RSB assembly as described in the diagram of FIG. 1. The tensile test can not be carried out directly. on an FSB / RSB assembly because of the fragility of these supports, the membranes (x) are bonded separately on 2 '/ 2 L-shaped sandblasted aluminum test pieces by means of an appropriate adhesive ( z) then the assembly of the FSB and RSB specimens thus made is carried out by means of the adhesive composition (y) to be tested on a surface of 50 mm × 50 mm and a joint thickness of 0.8 mm. .

The test piece thus produced is installed in the climatic chamber (thermoregulated at -170 ° C.) of the dynamometer and sheared at a speed of 1.3 mm / min until the assembly breaks. R: ABrevets \ 26500v26562-081029 -draft text.doc The maximum force reached in kiloNewton (kN) is recorded, which makes it possible to calculate the maximum value of stress (in MPa). All the exemplified compositions exhibit a very high shear tensile strength greater than 20 MPa at -170 ° C, characteristic of structural assemblies. Description of a particular mode of manual application of the glue. Figure 2 describes the method of manual application of the adhesive between 2 membranes and illustrates the notions of TC coverage time and TT total time. A manual application takes place as follows: 10 - The glue is previously extruded on a pallet (Taloche). - The operator then applies to the spatula a layer of thickness ranging from 0.2 to 5 mm, preferably from 0.2 to 2 mm of the adhesive on two strips of RSB 3 cm distant one of the other (Adjustment and expansion joint left between the reinforced foam panels). The RSB strips can be up to 3 m in length and can be placed vertically, horizontally (floor, wall or ceiling) or tilted at 45 ° C (Chamfer). - The operator then unfolds the FSB flexible membrane on the two RSB strips to be assembled, taking care to leave on each side an overflow of glue. This visible part of adhesive is called squeeze out and makes it possible to carry out checks on the adhesive (appearance (bubbling, foaming, regularity, etc.), hardness, etc.). The FSB is then mounted and an anti-adhesive film is applied. adhesive is deposited. - Lastly, the operator comes to put heating hot pads at 60 ° C for at least two hours by imposing a certain pressure (250 mBar). The use of hot pads (60 ° C) under pressure, has a dual purpose: - First fluidize the glue and help penetrate the FSB - Accelerate the kinetics of crosslinking relative to the ambient. The time between the start of extrusion of the glue on the pallet and the laying of the FSB is called the time at the cover (TC). The time between the beginning of the extrusion of the glue on the pallet and the laying of the hot pressure pads is called the total time (TT). A: ABrevets \ 26500 \ 26562-081029-text dep5tdoc If the increase in viscosity of the adhesive is too great after TC, the wettability on the FSB and therefore the adhesion properties but especially the sealing of the secondary barrier may not be insured. Similarly, if the viscosity of the adhesive is too high after TT, the drop in viscosity induced by the laying of the hot pads (60 ° C) under pressure may no longer be sufficient to promote the impregnation of the FSB and therefore the sealing. Therefore the adhesive composition used in the invention allows the assembly of the secondary barrier under the required conditions. The glue is applied with a TC and TT up to 40 min and 45 min, respectively, under climatic conditions (eg 30 ° C, 70% RH). It also meets the requirements of the International Gas Code required for LNG carriers (adhesion, sealing, resistance to liquid methane, seawater). Applicability of the mixture To judge the good applicability of the adhesive, in particular by manual removal, measure: - The initial viscosity of the mixture in order to know if the glue can be spatulated easily. This viscosity is measured with a Brookfield RVT viscometer (ISO Standard 2555, needle 7, 20 rpm) on 100 ml of adhesive, previously packaged at 23 ° C. and just extruded in a beaker.

The initial viscosity of the mixture corresponds to the lowest viscosity read. To meet the application constraints, the adhesive composition has a measured initial viscosity of between 27 and 120 Pa.s, preferably between 45 and 110 Pa.s, or even more preferably between 65 and 100 Pa.s.

The tendency to flow of the adhesive composition is determined as follows: a bead of 1 to 2 cm of glue previously conditioned at 23 ° C is extruded on a board placed vertically. We look at whether the cord keeps its original shape or not. In these conditions, the absence of coulure allows a manual removal of it but also its use with a robotic equipment. Lifetime (DVP) R_ABrevets`, 26500`26562-081029-text deposit.doc The pot life (DVP in minutes) of the mixture A + B is measured in a ratio of use 1/1 in volume to 23 ° C. This measurement gives an indication of the reactivity of the mixture at 23 ° C. For this, 50 ml of the resin portion A and 50 ml of the hardener portion B of the formulation are mixed in a jar to determine the time beyond which the mixture is set in bulk. This setting in mass is characterized by the absence of trace of glue on a tongue depressor brought to the intimate contact of the mixture. The DVP of the compositions is greater than 40 minutes and up to 140 minutes.

Intrinsic mechanical properties The flexibility of the adhesive is evaluated according to the following method: Test specimens H2 (see FIG. 3) are prepared for the size of the punch), about 3 mm thick by injection of the glue into a Teflon mold (Figure 3 for dimension of the test pieces). The mold is placed 120 minutes in a ventilated oven regulated at 60 ° C. The tensile test is carried out after 7 days of crosslinking at 23 ° C using a dynamometer (INSTRON model 1185) at 10 mm / min for elongation and tensile strength and 1 mm / min for the Young's modulus. - The elongation at break (in%) is given by the extensometer - The tensile strength (in MPa) corresponds to the force measured at break (in Newton) normalized by the section of the narrow part of the test piece (in mm2) measured precisely before the pull. - The Young's modulus (in MPa) which characterizes the rigidity of the material is determined from the tangent at the origin of the stress-strain curve. All compositions are capable of deforming more than 100% at room temperature before breaking at significant stresses and greater than 15 MPa. Their Young moduli, between 100 and 200 MPa are characteristic of relatively soft products. Open time The open time TO of an adhesive is defined as the time not to be exceeded before assembling the elements. Outside the TO, the desired properties are no longer assured: the adhesive is no longer sufficiently fluid (cross-linking too advanced) to ensure a good wetting of the support to be laminated. A: ABrevets \ 26500 \ 26562-08 1 029-text deposit.doc It is influenced by the ambient climatic conditions of application (humidity, temperature) but also depends for example on the thickness of the glue joint and the supports to assemble . In general, it is measured by assembling two elements at different times and looking at when a significant loss of adhesion properties is observed. Collages were thus made on INVAR / INVAR according to the method described above by assembling the INVAR test pieces after different waiting times at 23 ° C., 50% RH. The time from which the shear resistance value lost 20% of its initial value (waiting time before zero assembly) is noted. Depending on the reactivity required for the mode of application used, the adhesive compositions make it possible to obtain a broad TO range of up to 150 minutes. The open time is here mainly controlled by the nature of the polyols and or polyisocyanates used (eg: MIPI slower than Isonate ™ M143 because of the presence of the 2,2 'isomer of MDI) as well as by incorporation. An open time of between 90 and 150 minutes makes it possible to use the composition in manual application.The incorporation of a thermal release catalyst, of the blocked tertiary amine type, makes it possible to maintain a long TO at ambient temperature while accelerating hot crosslinking very strongly and thus increasing productivity The method used to report hot reactivity of glues is the measurement of Shore A hardness after 2 hours baking at 60 ° C. is extruded into a cup (48 mm diameter, joint thickness about 9 mm), then the glue cup is placed for 2 hours in a ventilated oven at 60 ° C. and then stored at 23 ° C. The hardness measurement shore A is eff after different times at 23 ° C (1h, 1 d and 7 d) with Shore A durometer - Zwick Equipment ASTM D 2240 A; I) IN 53505; ISO 868. The hardness corresponds to the value read 15 seconds after penetration of the tip of the durometer into the adhesive (3 measurements are systematically performed).

Sensitivity to climatic conditions: foaming phenomena. By nature, polyurethanes are sensitive to moisture (isocyanates react with the moisture of the air producing a gaseous release of CO2). R: ABrevets \ 26500 \ 26562-081029-text depositionT Foaming is the presence of a multitude of bubbles, whose size is less than one micron, regularly distributed in the structure of the adhesive. In tropical climatic conditions (30 ° C, 70% RH), a significant risk of foaming may also exist. In the case of two-component, the reaction with moisture is generally very minor, the most favorable reaction being that between polyisocyanates and polyols (or amines). It can nonetheless become significant when the quantity of water in the air is high (high temperature and relative humidity) and the exposure time of the glue in these conditions is long (for example if TC coverage time and TT total time are long). The presence of foaming in the glue joint can be particularly critical and harmful because it can not only weaken the glue joint but also affect the sealing of the secondary barrier (potential source of leakage). The sensitivity of the compositions to climatic conditions is determined by the presence or absence of foaming after hot crosslinking in the squeeze out (see FIG. 3) (manual application of the adhesive under the most discriminating conditions at 30 ° C., 70% RH, TC = 25 min, TT = 45 min). Under conventional climatic conditions (27 ° C, 55% RH) none of the compositions exhibit foaming. The use of hydrophobic additives such as castor oil or hydrophobic coated fillers (eg fatty acid coating) helps to reduce the sensitivity of glues to extreme weather conditions and therefore to foaming. Incorporation of a higher molecular sieve concentration (10 to 15% in Part A) traps the water before it reacts with the polyisocyanates and eliminates foaming.

Sealing The test put in place to evaluate the tightness of the joints is the NPA (Normal Porosity Area) test. It is carried out under the most extreme and disadvantageous application conditions (TC = 25 min, TT = 45 min at 30 ° C., 70% RH) and after hot crosslinking of the adhesive.

A satisfactory seal is guaranteed by a NPA value of less than 0.085 cm2. The leak test is carried out according to the procedure described below: A: 1Brevets \ 26500 ', 26562-08 IO29-text deposit.doc An RSB disc of about 1 m in diameter is hollowed out with the help of a template for making at the center of the disc two perpendicular slots of width 30 mm in the shape of a cross as described in the diagram of FIG. 4, while respecting a regular squeeze out of about 5 mm (overflow of the adhesive), glue the first FSB strip 25 minutes (820 mm x 250 mm) after the beginning of the removal of the adhesive (covering time or covering time) as described in the 2'd diagram of Figure 4, then we put in place the Hot-pad and the airbag for uniform stressing (250 to 300 mbar) and heating for 2 hours at 60 ° C, 45 minutes after removal of the adhesive (open time or open time) After releasing the assembly of the hot-pad and the air bag and cooling to room temperature, the same op is renewed. ration with the FSB second band as described in the third diagram of FIG 4. Place the disc whose cross is glued on a flat support, FSB face down. The cover is sealed on the RSB side with a lid 1m in diameter provided with a valve and a pressure and temperature indicator above the cross on the FSB side. The FSB face is subjected to a first thermal shock in the presence of liquid N 2 and then returned to ambient temperature. The vacuum is emptied under the lid until -530mbars then the rise in pressure is noted inside the cylinder. The time required to go from 450 mbar to 300 mbar (hours) allows the calculation of the equivalent leakage section (NPA) made after each thermal shock. The experience is repeated 7 times in a 24-hour period. An average leakage rate expressed in cm 2 is determined according to the following formula: NPA = (1.21 × 10 -3 × S-1) / (Aab × 10 -4 × At) NPA = equivalent leakage section or Normal Porosity Area (cm 2) Vuä = Volume under vacuum or Volume under vacuum (m3) is 0,0785 m3 Aab = Surface of the Secondary Barrier (m2) is 0,3475 m2 At = Time required to go from 450 mbar to 300 mbar (hours) R: ABrevets.26500 \ 2 6562-081029-text deposit.doc No bubbles in the glue joint Another requirement for this application is the absence of bubbles larger than 12 mm in the glue joint Whatever the TC or TT times and the ambient conditions of application, the presence of bubbles being all the more likely that the TCs and TTs are short, the tests are performed at TC = 10 minutes and TT = 15 minutes. The overall appearance of the glue joint is checked by peeling the FSB.It is noted that when incorporating a prepolymer polyurethane to ter Instead of conventional polyols in resin A to form longer and / or more branched chains, this has the effect of increasing the initial degree of crosslinking and of reducing the presence of bubbles. Application of adhesive compositions to the construction of secondary sealing barrier. The sealed and thermally insulating vessels comprising, at the level of the secondary sealing barrier, the cryogenic adhesive composition as a connecting layer between the rigid membrane and the flexible membrane are tanks integrated in a supporting structure, such as the shell of a ship intended for the sea transport of liquefied gas. For the manufacture and more general description of these integrated tanks, reference may be made to the teaching provided by patents FR 28822814, FR 2887010, FR 2781557 issued by Gaz Transport and Technigaz (GTT).

FIG. 5 represents a sectional diagram of a part of the sealed tank, such as the hull of a vessel intended for the sea transport of liquefied gas, with the membrane bonding zone concerned by the bonding of the membrane with the adhesive adhesive according to the invention. This membrane bonding zone is located between the rigid membrane integral with the reinforced PU foam panels and representing a constituent element of the secondary barrier and the flexible membrane used to assemble two secondary barrier elements. Above the flexible membrane is the insulation board (TBP = Top Bridge Pad) itself secured to the primary membrane in INVAR or stainless steel, in contact with the liquefied gas.

Of course, the present invention is not limited to the examples and to the embodiment described and shown, but it is capable of numerous variants accessible to those skilled in the art. Examples. A: Patents 26500 26562-081029-text deposit.doc Synthesis of parts A (compositions noted R in Table I). Example R1 71.5 g of Ethyl 2 hexane Diol 1.3, 11 μg of Terathane 650, 119.3 g of Capa 3050, 2.7 g of Byk 080A, 5.3 g of Antiterra 204 and 0.44 g of black are introduced into a glass reactor. smoke 101 powder previously pasted in 1.76g of polyBD R45HT. The mixture is evacuated and kept under constant stirring for 12 minutes. Then, the different sieves and fillers are incorporated in the following order: - 29.7g of siliporite SA 1720 - 462.3g of chalk BL200TB - 135.2g of socal chalk 312 Between each element incorporated, the mixture is kept 15 min under stirring and under empty. After making sure that all the sieves and fillers are perfectly dispersed, 13.5g of Jeffamine T403 and 4.7g of unithox previously dissolved in hot in 42.6g of Jarysol XX are introduced. The mixture is finally stirred for 1 hour under vacuum. The mixture R1 is gray in color, Brookfield viscosity (23 ° C, A7 20T) of 53 Pa.s and density 1.63. Mixtures R2 to R4 are prepared identically to the procedure of R1 using the ingredients shown in Table I.

EXAMPLE R5 120.2 g of CAPA 3050, 146.8 g of castor oil and 15 g of Thixatrol ST are introduced into a glass reactor. The mixture is kept under constant stirring at 80 ° C. under vacuum for 60 min in order to develop Thixatrol's thickening character. The mixture is cooled to room temperature (approximately 25 ° C.) and 245 g of UOP L Pate and 10 g of BYK 080 are then introduced. Thereafter, 430 g of Mikhart C are incorporated and the mixture is kept stirring for 20 minutes under vacuum. . After making sure that the charges are perfectly dispersed, 0.5 g of Blue Carbidex G dissolved beforehand in 20 g of Jarysol XX, 72 g of Ethyl 2 hexane 1.3 Diol and 6 g of piperazine dissolved beforehand in 11.2 g of hot water are then added successively. Voranol CP450. The mixture is finally stirred for 1 hour under vacuum. The R5 mixture is blue in color, Brookfield viscosity (23 ° C, A7 20T) of 35.8 Pa.s and density of 1.42. A: Mixtures R6 to R7 are prepared identically to the procedure of R5 using the ingredients shown in Table I. Example R9 In a glass reactor, 120.2 g are introduced. of CAPA 3050, 146.8g of Castor Oil and 30g of Isonate M143. The mixture is kept under constant stirring at 80 ° C. under vacuum for 90 min in order to consume all the NCO functions. The hydroxyl-terminated polyurethane prepolymer thus synthesized has a theoretical pH of 167. The prepolymer is cooled to room temperature (approximately 25 ° C.). In this mixture, 245 g of UOP L Pate and 10 g of BYK 080 are then introduced. silica and the filler are incorporated in the following order: - 8g of Aerosil R202 - 430g of Mikhart C Between each incorporated element, the mixture is maintained 20 min with stirring and under vacuum. After making sure that all the charges are perfectly dispersed, 0.5 g of Blue Carbidex G dissolved beforehand in 20 g of Jarysol XX, 72 g of Ethyl 2 hexane 1.3 Diol and 8.5 g of piperazine dissolved beforehand in hot form are added successively. 8.5g of Voranol CP450 as well as 0.3g Polycat catalyst SA 1/10. The mixture is finally stirred for 1 hour under vacuum.

The R9 mixture is blue in color, Brookfield viscosity (23 ° C, A7 20T) of 30 Pa.s and density of 1.42. Synthesis of Parts B (compositions denoted D in Table II). EXAMPLE D1 597.6 g of Isonate M143 and 291 g of Theratane 650 are introduced into a glass reactor. The mixture is stirred at 80 ° C. under vacuum for 1 hour in order to consume all the OH functions. The polyurethane prepolymer thus synthesized has a% NCO of 15.4%. The prepolymer is cooled to room temperature (about 25 ° C). Then, the sieve and the fumed silica are incorporated in the following order: 88.9 g siliporite SA 1720 - 22.5 g Aerosil Between each incorporated element, the mixture is maintained 15 min with stirring and under vacuum. The mixture is finally stirred for 1 hour under vacuum. A Synthesis Dl is beige color, Brookfield viscosity (23 ° C, A7 20T) of 38 Pa.s and density 1.18. Blends D2 to D7 are prepared identically to the procedure of D1 using the ingredients shown in Table II.

EXAMPLE D9 265.6 g of Isonate M143, 265.6 g of Lupranat MIPI and 357.4 g of Theratane 650 are introduced into a glass reactor. The mixture is stirred at 80 ° C. under vacuum for 1 hour in order to consume all the elements. OH functions. The polyurethane prepolymer thus synthesized has a% NCO of 13.5%. The prepolymer is cooled to room temperature (about 25 ° C). Then, the sieve and the fumed silica are incorporated in the following order: -88.9 g of siliporite SA 1720 -14 g of Aerosil Between each element incorporated, the mixture is maintained 15 min with stirring and under vacuum. The mixture is finally stirred for 1 hour under vacuum. The D9 mixture is beige in color, Brookfield viscosity (23 ° C, A7 20T) of 26 Pa.s and density 1.18. Synthesis of compositions A + B (compositions denoted C and T in Table III) and evaluation of A / B couples).

The composition T7 is a reference composition without a threshold agent which has a very strong flow and is not compatible with the desired application. The resin RI and the hardener D1 are used in a two-volume ratio in volume ratio of 1 to 1, which corresponds to a number of NCO function on a number of functions (01-I + NH) of 1.1. This adhesive composition named Cl is suitable for applications with short open times. Composition C2 is particularly sensitive to extreme weather conditions: while no anomaly is found at 27 ° C, 55% RH, a very large foaming (accompanied by expansion of volume) appears at 30 ° C, 70% RH . For the other compositions, foaming is less or nonexistent.

Similarly, while the C2 has an open time at room much higher than that of the Cl, the incorporation of the thermal trigger catalyst provides a reactivity at 60 ° C identical or slightly better. C3 has a more hydrophobic and slightly slower formula than C2, which reduces foaming. The change of dye in C4 with respect to C3 also makes it possible to improve the foaming.

The resin R5 and the hardener D5 are used in two-part ratio in volume ratio of 1 to 1, which corresponds to a number of NCO function on a number of functions (OH + NH) of 1.08. This adhesive composition, called C5, is suitable for long open-time applications but has problems with bubbling at short open times in the specific case of the application for assembling the C5 barrier to an even more hydrophobic and slower formula than C4. and no longer gives rise to foaming. Its reactivity is slowed down by using the MIPI isocyanate. In C6 with respect to C5, a heat-triggered catalyst is added in order to have a satisfactory TC and T7 'at 30 ° C and a faster temperature crosslinking. Comparing example C5 and C6, it is found that the addition of the catalyst makes it possible to accelerate the hot crosslinking very strongly while maintaining a very long TO in both cases. The open time is mainly controlled by the nature of the isocyanates used in Part B. It is observed that the open times are longer in the presence of Lupranat MIPI (C5 to C9) compared to the presence of Isonate M143 alone (C1 to C4). ) because of the presence of 2,2 'isomer of MDI. The resin R9 and the hardener D9 are used in two-fluid ratio in a volume ratio of 1 to 1, which corresponds to a number of NCO function on a number of functions (OH + NH) of 1.06. This adhesive composition named C9 meets all the specifications. R: \ Patents \ 26500 \ 26562-081029 -Declaration text.doc al al ddde 31 Table I Part A (Resin) Names Nature Chemical R1 R2 R3 R4 R5 R6 R7 R9 Commercial (Suppliers) Voranol CP 450 Polyol Polyether 10H = 380 mg KOH / g, F = 3, 0.93% 0.95% 0.95% 1.04% 1.04% 0.70% 0.76% (Dow) Mn = 443 Terathane 650 Polytetramethylene glycol 11.10% 11.18% 5.28% 5.29% (Invista) 10H = 174 mg KOH / g, F = 2, Mn = 644 Capa 3050 Polycaprolactone 11.93% 12.02% 11.18% 11.19% 11 , 16% 11.16% 11.26% 10.78% (Solvay) 10H = 310 mg KOH / g, F = 32, Mn = 540 Vegetable Polyol Castor Oil 10.69% 10.71% 13.63% 13.63% 13.75% 13.17% (Nidera) 10H = 164 mg KOH / g, F = 2.8, Mn = 958 PolyBd R45 HT Polybutadiene with hydroxyl endings 0.18% 0.18% 0, 16% (Arkerna) 10H = 46mg KOHig, F = 2.8, Mn = 2800 Isonate M 143 MDI oligomer 2.69% (Dow)% NCO = 29.2, F = 2.2 Jeffamine T 403 Primary polyetheramine 1 , 35% (Huntsman) Total alcohol = 6.5 meq / g, F = 3, Mn = 461 Piperazine Secondary diamine 0.50% 0.51% 0.51% 0.56% 0.56% 0.7 6% (Delamine BV) Total Alk = 23 meq / g, F = 2, M = 86 Ethyl-2-hexane-1,3-Diol (chain extender) 7.15% 7.20% 6.69% 6 , 71% 6.69% 6.68% 6.75% 6.46% 10H diol = 768 mg KOH / g, F = 2, M = 146 (Krahn Chemie) UOP L Paste Zeolite (50) 10.23% 10.25% 11.38% 11.38% 11.48% 10.99% (UOP) Castor oil (50) 10.23% 10.25% 11.38% 11.38% 11.48% 10 , 99% Siliporite SA 1720 Synthetic zeolite 2.97% 2.99% (Arkema) Chalk BL 200 TB Calcium carbonate 46.23% 54.19% (Omya) Average diameter = 9 microns Socal 312 Hydrophobed calcium carbonate 13, 52% 6.01% (Solvay) Average diameter = 1 micron Mickhart C Hydrophobized calcium carbonate Diameter 39.98% 40.05% 39.94% 39.92% 40.29% 38.57% (La Provençale) medium = 2.5 microns Unithox 420 Ethoxylated fatty alcohol 0.47% 0.47% (Baker Hughes) R: Extracts \ 26500 \ 2 65 62-08 IO29-Deposit text.doc eeeeeeef 32 Byk 080 Polymer antifoam composition 0 , 27% 0.93% 0.93% 0.93% 0.93% 0.94% 0.90% (Byk) and polysiloxanes in polypropylene glycol Antiterra 204 Surfactant composition based on 0.53% acid salt 0.09% 0.09% (Byk) ecarboxylic and polyamidoamine Jarysol XX Mono and bis (xylyl) xylene 4.26% 4.26% 1 , 86% 1.86% 1.86% 1.86% 1.87% 1.79% (Arkema) Smoke Black 101 Carbon Black 0.04% 0.04% 0.04% Powder (Evonik) Blue Carbidex G 1,4-di- (n-butylamino) anthraquinone 0.05% 0.05% 0.05% 0.05% 0.04% (Steiner) Thixatrol ST Thickening agent derived from castor oil 1, 39% 1.39% 1.41% 1.35% (Rheox / Elementis) Aerosil R 202 fumed silica type thickener 1.16% 1.16% 0.72% (Evonik) Polycat SA 1/10 1 , 8-diazabicyclo [5.4.0] undecene-7 0.02% 0.03% 0.03% 0.03% (Air Products) 100.00% 100.00% 100.00 100.00% 100 , 00% 100,00% 100,00% 100,00%% Characteristics part A (resin) Color gray gray gray blue blue blue blue blue Density 1,63 1,65 1,42 1,42 1,42 1,42 1.42 1.42 Brookfield Viscosity (23 ° C, Needle 7, 20 rpm) in Pa.s 53.0 27.0 28.0 23.0 35.8 32.2 32.0 30.0 R : \ Patents \ 26500 \ 2 6562-08 1 02 9-tex Table B Part B (hardener) Names Chemical Nature D1 D2 D3 D4 D5 D6 D7 D9 Commercial (Suppliers) (Sonata M 143 MDI Oligomer 58.85% 58.85% 59.79% 59 , 79% 28.36% 28.36% 28.36% 26.47 (Dow)% NCO = 29.2, F = 2.2% Lupranat MIPI Mixture of MDI-2,4 'and MDI-4, 4 '28.36% 28.36% 28.36% 26.47 (Elastogran) (50/50)% NCO = 33.5, F = 2 Terathan 650 Polytetramethylene glycol 28.66% 28.66% 29, 11% 29.11% 31.92% 31.92% 31.92% 35.62 (Dupont) 10H = 174 mg KOH / g, F = 2, Mn = 644 Siliporite SA 1720 synthetic zeolite 8.75% 8, 75% 8,89% 8,89% 8,87% 8,87% 8,87% 8,86 (Arkema)% Aerosil R 202 Silica thickener 3,74% 3,74% 2,20% 2 , 20% 2.49% 2.49% 2.49% 2.59 (Evonik) pyrogenous% 100.00% 100.00% 100.00 100.00 100.00 100.00 100.00 100.0% %%%% 0% Characteristics Part B (hardener) Color beige beige beige beige beige beige beige beige Density 1.18 1.18 1.17 1.18 1.18 1.18 1.18 1.18 Viscosity Brookfield (23 ° C, needle 7, 20 rpm) in Pa.s 38.0 38.0 22.0 22.0 25.0 25.0 25.0 26.0, R: \ Patents \ 26500 \ 2 65 62-08 1 02 9-text deposit.doc 34 table III compositions Characteristics Mixture A / B (1/1 adhesives Cl C2 C3 C4 C5 C6 T7 C9 ratio NCO / NH + OH 1.13 1.07 1.1 1.09 1.08 1.08 1.14 1.06 Lifetime in pot at 23 ° C or DVP (minutes) 40 64 95 83 133 120 117 100 Brookfield Viscosity (23 ° C, Needle 7, 20 rpm) 62.0 54.6 57.6 48.2 57.2 52.8 26 , 0 80.0 in Pa.s Coulure at 23 ° C low no no no no no yes no Elongation at break or RE at 23 ° C (%) 152 +/- 5 151 + 1-5 166 +/- 7 169 +/- 13 141 + 1-16 149 +/- 4 190 +/- 15 Resistance to fracture or RR at 23 ° C (Mpa) 17.8 +/- 1.1 16.4 + 1- 1.4 16.8 1- 0.9 18.3 + / - 2 15.3 +/- 2 17.1 + 1- 0.9 18.3 + i- 2 Young's modulus at 23 ° C (MPa) 210 +/- 10 197 +/- 6 119 +/- 4 126 +/- 7 151 +/- 3 155 +/- 7 148 +/- 7 Tensile strength-shearing INVAR / 22.4 +/- 1 22.7 +/- 1.7 17.2 +/- 1 19.6 +/- 1.2 20.7 +/- 1.2 22.7 + / - 0.9 21.3 +/- 1.5 INVAR at 23 ° C and 50% RH (MPa) Tractio resistance n-shear FSB / RSB 20.5 24.0 25.0 26.3 23.9 24.0 22.0 at -170 ° C (MPa) Open time of glues on INVAR / INVAR at 25 70 85 90> 120 > 120> 120 23 ° C and 50% RH (minutes) Shore A hardness (reactivity at 2h at 60 ° C + 80 81 63 63 19 75 80 hot) 1h at 23 ° C 2h at 60 ° C + 89 87 76 77 57 80 83 1j at 23 ° C 2h at 60 ° C + 93 93 88 87 85 86 88 7j at 23 ° C Characteristics Application Manual FSB / RSB TC = 25 min, TT = 45 min at 30 ° C foaming yes yes weak no no no and 70% RH NPA (cm2) 0.163 0.024 0.061 0.000 0.001 0.003 TC = 10 min, TT = 15 min at 30 ° C Presence of no no yes yes yes yes yes no bubbles> 12 mm and 70% RH R: \ Patents \ 26500 \ 26562-081029-deposit text.doc

Claims (15)

REVENDICATIONS1. Use of a two-component polyurethane adhesive composition having a shear strength measured according to ISO 4587 which is greater than 10 MPa over the entire temperature range of -170 ° C to + 40 ° C 2. Use according to claim 1 wherein the adhesive composition serves as an adhesion element between two substrates to form a multilayer structure adapted to seal against gases and liquids. 3. Use according to claim 1 or 2 wherein the adhesive composition is obtained by reaction between a part A called resin and a part B called hardener, Part A being represented by the mixture comprising the ingredients: a) at least one selected polyol of the polyol polyethers (a1), the polyester polyols (a2), the unsaturated polyols (a3), the hydroxyl-terminated thermoplastic polyurethane prepolymers (a4), each of the components al to a4 having an average molecular mass of between 200 and 9000 g / mol and OH functionality of between 2 and 4.6; b) at least one threshold agent selected from the group of primary or secondary amines or polyamines; c) optionally a chain extender selected from the group of C 2 -C 10 diols; (d) inorganic fillers; e) at least one additive selected from the group of wetting agents, defoamers, dispersants, dyes, thickeners, fluidifying agents; f) optionally a thermal release crosslinking catalyst; Part B being represented by the composition comprising the ingredients: g) at least one NCO-terminated polyurethane prepolymer having an average molecular weight of between 840 and 2100 g / mol and of NCO functionality of between 2 and 4; (h) inorganic fillers; i) at least one additive selected from the group of thickeners, fluidifying agents. 10 4. Use according to claim 3 wherein the proportions of the different ingredients are as follows: a) the polyol represents 20 to 60% by weight of the part A, preferably 2345%; b) the threshold agent is from 0.4 to 3% by weight of Part A, preferably 0.5 to 1.5%; c) the chain extender represents from 0 to 10% by weight of the part A, preferably 4 to 8%; d) the fillers represent 22 to 70% by weight of the part A, preferably 35 to 65%; E) the additives represent from 2 to 6% by weight of the part A, preferably 3 to 4%; f) the catalyst is 0 to 0.05% by weight of the B part, preferably 0.01 to 0.04%; g) the NCO prepolymer is 75 to 100% by weight of the B part, preferably 85 to 90%; h) the inorganic fillers represent from 0 to 20% by weight of the B part, preferably 5 to 15%; i) the additives represent from 0 to 5% by weight of the part B, preferably 1 to 3%; R: ABrevets \ 26500 \ 26562-081029 -draft text.docet the ratio of NCO functions (meq / g) of part B to the sum of the reactive functions OH (meq / g) and NH (meq / g) of the part A ranging from 0.90 to 1.20, preferably from 1.00 to 1.10. 5. Use according to claim 4 wherein d) the inorganic fillers are distributed between 2 to 15% by weight of Part A, preferably 10 to 15% of molecular sieve, and 20 to 65% by weight of Part A preferably 25 to 50% of mineral fillers. 6. Use according to one of claims 1 to 5 wherein the polyol a) of part A is at least one OH-terminated thermoplastic polyurethane (a4) selected from aliphatic and aromatic polyurethane prepolymers, and mixtures of these compounds. 7. Use according to one of claims 1 to 6 wherein the adhesive composition is obtained by reaction of Part A with Part B in a volume ratio A / B ranging from about 0.85 to about 1.15 preferably in a ratio of about 1, and has an initial viscosity measured according to ISO 2555, between 27 and 120 Pa.s, preferably between 45 and 110 Pa.s or 65 to 100 Pa.s. 8. Use according to one of claims 1 to 7 wherein the compound b) is represented by piperazine and its derivatives. 9. Use according to one of claims 1 to 8 wherein the compound a) comprises at least one vegetable polyol of hydrophobic nature, preferably represented by castor oil and the compound d) comprises at least one inorganic filler coated with a hydrophobic coating, preferably with a molecular sieve. R .. ^ ~ Patents \ 26500 \ 26562-081029-Deposit text.doc 10. Use according to one of claims 1 to 9 wherein the adhesive composition has an open time ranging from 90 minutes to 150 minutes, the open time being the time from which the value of shear strength measured according to ISO 4587 lost 20% of its original value. 11. Use according to one of claims 1 to 10 wherein the polyurethane adhesive composition is located between a flexible membrane (FSB) and a rigid membrane (RSB) to form the multilayer structure. 10 12. Use according to one of claims 1 to 11 comprising applying the adhesive composition, after extrusion, manually or automatically between at least one strip of a rigid membrane and at least one strip of a flexible membrane with a thickness of between 0.2 and 5 mm, under climatic conditions of high temperature and relative humidity RH, preferably T greater than 25 ° C. and HR greater than 55%, preferably T between 28 and 40 ° C. , and HR between 60 and 85%. 13. Use according to one of claims 1 to 12 wherein the multilayer structure represents the secondary sealing barrier of a tank integrated in a supporting structure, such as the hull of a vessel intended for the sea transport of gas liquefied. 14. Adhesive composition obtained by reaction between a part A called resin and a part B called hardener, Part A being represented by the mixture comprising the ingredients: a) from 20 to 60% by weight of part A, preferably 23 at 45% of at least one polyol chosen from polyol polyethers (a1), polyester polyols (a2), unsaturated polyols (a3), hydroxyl-terminated thermoplastic polyurethanes (a4), each of components a1 to average molecular weight of between 200 and 9000 g / mol and of OH functionality: between 2 and 4.6; polyol a) of part A comprising at least one OH-terminated thermoplastic polyurethane prepolymer (a4) chosen from aliphatic and aromatic polyurethane prepolymers, and mixtures of these compounds; b) from 0.4 to 3% by weight of the portion A, preferably 0.5 to 1.5% of at least one threshold agent selected from the group of primary or secondary amines or polyamines; c) from 2 to 10% by weight of the portion A, preferably from 4 to 8% of at least one chain extender selected from the group of C2 to C10 diols; d) from 22 to 70%, by weight of the part A, preferably from 35 to 65% of inorganic fillers; e) from 2 to 6% by weight of the part A, preferably 3 to 4% of at least one additive chosen from the group of wetting agents, defoamers, dispersants, dyes, thickening agents, fluidifying agents ; f) from 0 to 0.05% by weight of the B part, preferably 0.01 to 0.04% of a thermal release crosslinking catalyst; Part B being represented by the composition comprising the ingredients: g) from 75 to 100% by weight of the B part, preferably 85 to 90% of at least one NCO-terminated polyurethane prepolymer having an average molecular weight of and 2100 g / mol and NCO functionality of 2 to 4; h) from 0 to 20% by weight of the B part, preferably 5 to 15% of inorganic fillers; i) from 0 to 5% by weight of the B part, preferably 1 to 3% of at least one additive selected from the group of thickeners, fluidifying agents; and the ratio of the NCO functions (meq / g) of part B to the sum of the reactive functions 01-1 (meq / g) and NH (meq / g) of part A ranging from 0.90 to 1.20 of preferably from 1.00 to 1.10. 15. An adhesive composition according to claim 14, wherein the polyurethane prepolymer (a4) is obtained by polyaddition of at least one polyol of type (a) to (d4) and (d4). at least one polyisocyanate in amounts such that the NCO / OH ratio is between 0.1 and 0.5. R: \ Patents' \ 26500`2 6 562-08 1 02 9-text deposit.doc