FORMULATION OF A POLYURETHANE / POLYISOCYANURATE FOAM

Abstract

This technology relates to a polyol blend comprising three (3) different polyols and one chain-extending polyol. This blend is used to prepare polyurethane / polyisocyanurate (PUR / PIR) foam when the blend is reacted with at least one polyisocyanate compound in the presence of catalysts, blowing agents, and possibly other additives. This technology therefore also relates to a PUR / PIR foam composition, the resulting foam, and its production process. The PUR / PIR foam exhibits interesting physical characteristics and properties, particularly in terms of density, mechanical strength, and thermal conductivity.

Description

Title of the invention: FORMULATION OF A POLYURETHANE / POLYISOCYANURATE FOAM FIELD OF INVENTION

[0001] The present technology relates to a blend of polyols for the preparation of a polyurethane / polyisocyanurate (PUR / PIR) foam. The blend comprises three (3) different polyols and a chain-extending polyol. This blend yields a PUR / PIR foam particularly suitable for use as thermal insulation. The present technology also relates to a composition for the formulation of said PUR / PIR foam, the foam obtained, and its production process.

[0002] BACKGROUND OF THE INVENTION

[0003] Polyurethanes or polymers composed of one or more urethane molecules are well known to those skilled in the art and are now used in many fields as insulators, adhesives, or as compounds for the automotive, textile or furniture industries.

[0004] Polyurethanes are most commonly used in the form of foams: polyurethane (PUR), polyisocyanurate (PIR), and polyurethane / polyisocyanurate (PUR / PIR) foams, which can be flexible or rigid. The formation of foams is well known to those skilled in the art and involves a polymerization or condensation reaction of polyols with isocyanate compounds. The nature of the compounds, their quantity, and the presence of additives allow for the production of polyurethane foams with different characteristics and properties specific to each composition.

[0005] PUR foams are used in the automotive industry as flexible foam or in thermal insulation as rigid foam. PUR / PIR and PIR foams are also used as thermal insulation. These foams have the advantage of better fire-resistant properties and higher compressive strength than PUR foams.

[0006] PUR, PIR and PUR / PIR foams are classified according to the isocyanate / polyol ratio, the formation mechanism of PIR and PUR / PIR foams being similar to that of PUR foams.

[0007] Several compositions for the formulation of PUR / PIR foams are described in the prior art, including US patent applications 2010 / 0116829 and WO 2020 / 104749 or US patent 8,940,803.

[0008] However, none of the compositions makes it possible to obtain a foam having both a good thermal coefficient, satisfactory mechanical properties meeting industry specifications, and whose foam composition viscosity allows for homogeneous distribution.

[0009] The inventors have thus discovered a composition for the formulation of a polyurethane foam that meets at least some of the shortcomings observed in the technical field so far.

[0010] BRIEF DESCRIPTION OF THE INVENTION

[0011] The present technology relates to a polyol blend, characterized in that the polyol blend comprises three (3) different polyols and one chain-extending polyol, said different polyols being selected from polyether polyols and polyester polyols. This blend is used for the formulation of a polyurethane / polyisocyanurate (PUR / PIR) foam, the foam composition comprising said polyol blend, at least one polyisocyanate compound, and a catalyst.

[0012] The present technology relates to a mixture of polyols, characterized in that the polyether polyols are glycerol and sorbitol based polyols and / or glycerol and sucrose based polyols.

[0013] The present technology relates to a mixture of polyols, characterized in that the polyester polyols are aromatic polyester polyols, preferably derivatives of phthalic acid.

[0014] The present technology relates to a mixture of polyols, characterized in that the chain-extending polyol is a glycol-type derivative, preferably of di-propylene glycol.

[0015] The present technology relates to a mixture of polyols, characterized in that the mixture has a viscosity between 400 and 800 mPa.s at 25 °C.

[0016] The present technology relates to a mixture of polyols, characterized in that it comprises:

[0017] - from 28 pp to 100 pp of polyether polyols, and from 18 pp to 67 pp of a first polyol polyether and 10 pp to 25 pp of a second polyether polyol,

[0018] - from 5 pp to 40 pp of a polyester polyol, and

[0019] - from 15 pp to 30 pp of a chain-extending polyol.

[0020] The present technology therefore also relates to the composition of the foam, which may further include expanding agents and additives.

[0021] The present technology therefore also relates to the composition of a PUR / PIR foam, characterized in that the composition comprises:

[0022] - the polyol mixture comprising three (3) different polyols and one extending polyol chain, as defined in this technology,

[0023] - at least one polyisocyanate compound, and

[0024] - a catalyst.

[0025] The present technology therefore also relates to the composition of a PUR / PIR foam, characterized in that the composition comprises between 90 pp and 120 pp of polysiocyanate for 100 pp of polyols.

[0026] The present technology therefore also relates to the composition of a PUR / PIR foam, characterized in that the polyisocyanate is chosen from aromatic diisocyanates, preferably the isocyanate compound is methylene diphenyl diisocyanate (MDI).

[0027] The present technology therefore also relates to the composition of a PUR / PIR foam, characterized in that the catalyst is chosen from among stannic catalysts and potassium carboxylates, or a mixture of these.

[0028] The present technology therefore also relates to the composition of a PUR / PIR foam, characterized in that the composition further comprises an expanding agent chosen from water, CO2 and fluorinated expanding agents, or a mixture thereof.

[0029] The present technology therefore also relates to the composition of a PUR / PIR foam, characterized in that it further comprises one or more additives.

[0030] The present technology also relates to the PUR / PIR foam obtained which has the following characteristics: a density between 110 kg / m3 and 130 kg / m3, a thermal conductivity between 24 mW / mK and 26 mW / mK, and / or a compressive stress between 1.30 MPa and 1.50 MPa.

[0031] The present technology also relates to the PUR / PIR foam obtained from the composition defined above.

[0032] The present technology also relates to PUR / PIR foam, characterized in that said foam has a density between 110 and 130 kg / m3.

[0033] The present technology also relates to PUR / PIR foam, characterized in that said foam has a thermal conductivity between 24 and 26 mW / mK

[0034] The present technology also relates to PUR / PIR foam, characterized in that said foam has a compressive stress between 1.30 and 1.50 MPa.

[0035] The present technology further comprises a method for manufacturing said PUR / PIR foam, said method comprising the steps of: i. bring into contact at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and one chain-extending polyol, said polyols being selected from polyether polyols and polyester polyols, in the presence of catalyst(s), expanding agent(s) and optionally flame retardant(s) and additive(s); ii. deposit the PUR / PIR foam composition onto a stack of fiberglass or glass mat, and iii. Allow the said formulation to solidify after expansion so as to form a block of foam.

[0036] The foam thus obtained can be used as thermal insulation, and more particularly as insulation for LNG carrier tanks.

[0037] The present technology also relates to the use of polyurethane / polyisocyanurate foam defined above, or obtained according to the process defined above, for thermal insulation. DETAILED DESCRIPTION OF THE INVENTION

[0038] Definitions

[0039] Within the context of this technology, the term "approximately" is used explicitly or implicitly. Each quantity presented in the context of this description refers to the actual value given, but also to the approximation of that given value that would be reasonably deduced based on knowledge of the craft, including equivalents and approximations due to experimental and / or measurement conditions for such a given value. For example, the term "approximately" in the context of a given value or range refers to a value or range that is less than 20%, preferably less than 15%, more preferably less than 10%, more preferably less than 9%, more preferably less than 8%, more preferably less than 7%, more preferably less than 6%, and more preferably less than 5% of the given value or range.

[0040] In the context of this technology, "polyols" means any organic compound bearing at least two hydroxyl groups (-OH) in its molecular structure. The reactivity of polyols is defined by various parameters such as functionality, hydroxyl number, and aromaticity.

[0041] The functionality refers to the average number of reactive hydroxyl groups present per molecule. During foam production, the hydroxyl groups react with isocyanate groups (-NCO) that are bonded to the isocyanate compounds.

[0042] The hydroxyl number, or OH number, also denoted IOH, of polyols refers to the number of reactive hydroxyl (-OH) groups available for the reaction. The hydroxyl number is expressed in milligrams (mg) of potassium hydroxide (KOH) equivalent to the hydroxyl content of one gram (g) of polyols, and is denoted "mg KOH / g polyols" in this application. The hydroxyl number is thus determined according to ASTM D4274-16. Determining the hydroxyl number allows, in particular, the assessment of the effectiveness of the crosslinking of the formulation.

[0043] The aromaticity of compounds is an intrinsic property due to the presence of a cyclic, planar, and particularly stable structure. A compound is said to be aromatic if its structure satisfies Hückel's rules.

[0044] The term "polyether polyol" refers to polyols comprising one or more functional groups. ether functionalities within their molecular structure. The term "polyester polyol" refers to polyols comprising one or more ester functionalities within their molecular structure.

[0045] The expression "chain-extending polyol" refers to polyol molecules which have the role of promoting the formation of chemical bonds and improving the physical properties of the compound(s) obtained when these same molecules enter into the synthesis of the final product in a covalent manner.

[0046] The term "isocyanate compound" or "isocyanate" means any compound comprising at least one isocyanate functional group within its molecular structure. The terms "polyisocyanate compound" or "polyisocyanate" refer to any organic compound bearing at least two isocyanate (-NCO) groups within its molecular structure.

[0047] PUR, PIR, and PIUR foams are obtained by chemical reaction between polyols and polyisocyanates, and exhibit different properties depending on the nature of the compounds and the proportions used in their formulation. They are notably defined by the isocyanate / polyol ratio (NCO / OH), also called the Index, which corresponds to the ratio of the number of isocyanate groups divided by the number of hydroxyl groups in the polyols and any other component bearing such groups.

[0048] We thus distinguish polyurethane (PUR) foams which have an NCO / OH ratio between 1:1 and 1.3:1, polyurethane / polyisocyanurate (PUR / PIR) foams which have a ratio between 1.3:1 and 1.8:1, and polyisocyanurate (PIR) foams which have a ratio between 1.8:1 and 2.8:1.

[0049] The term "foam" refers to a compound with a three-dimensional, expanded, cellular structure. The foam is obtained by the chemical reaction between polyisocyanates and polyols in the presence of other compounds, including catalysts and expanding or blowing agents. The resulting foam can be rigid or flexible, with open or closed cells. According to the present technology, PUR / PIR foam is a rigid foam comprising closed cells and storing a gas.

[0050] The "closed gas-storing cells" referred to in the present technology contain a gas originating from the blowing agent, either by a chemical reaction in the case of a chemical blowing agent, such as carbon dioxide (CO2) if the chemical agent is water, or from a physical blowing agent such as nitrogen (N2), oxygen (O2), carbon dioxide (CO2), hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, or mixtures thereof. The physical blowing agents are in gaseous or liquid form and disperse throughout the liquid mass of the copolymer. During foam formation, nucleation and bubble growth occur. They then generate a closed cellular structure that stores the gas.

[0051] The expressions "expanding agent" or "blowing agent" refer to compounds which induce, by chemical and / or physical action, an expansion of the composition during the foaming step.

[0052] In addition to the compounds essential to their formulation, PUR / PIR foams may include flame retardants. As the name suggests, flame retardants refer to compounds having the property of reducing or preventing the combustion or heating of materials comprising said compounds.

[0053] Within the framework of the present technology, the various ingredients comprising the PUR / PIR foam are defined as percentages relative to the total weight of polyols. The content of the various ingredients can also be expressed as a weight fraction (wp) or weight fraction relative to the total weight of polyols in the composition.

[0054] Mixture of polyols

[0055] The present technology relates to a blend of polyols for the preparation of a polyurethane / polyisocyanurate (PUR / PIR) foam, characterized in that the blend of polyols comprises three (3) different polyols and one chain-extending polyol, said different polyols being selected from polyether polyols and polyester polyols.

[0056] Polyether polyols and polyester polyols used in compositions for the formulation of PUR / PIR foams are well known to those skilled in the art.

[0057] Polyether polyols

[0058] Polyether polyols used in PUR / PIR foam compositions generally have a molecular weight between about 150 g / mol and about 1600 g / mol, a functionality between 3 and 8, and a hydroxyl number between about 250 mg KOH / g of polyols and about 1000 mg KOH / g of polyols.

[0059] In the context of this technology, the polyether polyols have a molecular weight less than or equal to approximately 1000 g / mol, preferably less than or equal to approximately 800 g / mol. In one embodiment, the polyether polyols have a molecular weight greater than or equal to approximately 200 g / mol. In another embodiment, the polyether polyols used in the composition of the PUR / PIR foam have a molecular weight between approximately 200 g / mol and approximately 800 g / mol. Advantageously, the polyether polyols according to the technology have a molecular weight between approximately 200 g / mol and approximately 600 g / mol, preferably between approximately 300 g / mol and approximately 600 g / mol.

[0060] In another embodiment, the polyether polyols have a molecular weight between approximately 350 g / mol and approximately 600 g / mol, between approximately 400 g / mol and approximately 600 g / mol, between approximately 450 g / mol and 600 g / mol, or between approximately 500 g / mol and 600 g / mol. Advantageously and in another embodiment, the polyether polyols used in the composition of the PUR / PIR foam have a molecular weight between about 550 g / mol and about 600 g / mol, preferably between about 580 g / mol and about 600 g / mol.

[0061] The polyether polyols included in the polyol mixture for preparing a PUR / PIR foam have a hydroxyl value between approximately 50 mg KOH / g of polyols and approximately 850 mg KOH / g of polyols. In the present technology, the mixture comprises polyether polyols with a hydroxyl value less than or equal to approximately 800 mg KOH / g of polyols, preferably less than or equal to approximately 700 mg KOH / g of polyols, or even less than or equal to approximately 600 mg KOH / g of polyols. In one embodiment, the polyether polyols have a hydroxyl value of between about 50 mg KOH / g of polyols and about 600 mg KOH / g of polyols, preferably between about 100 mg KOH / g of polyols and about 600 mg KOH / g of polyols, more preferably between about 200 mg KOH / g of polyols and about 600 mg KOH / g of polyols.In another embodiment, the polyether polyols have a hydroxyl value of between about 100 mg KOH / g of polyols and about 300 mg KOH / g of polyols, between about 200 mg KOH / g of polyols and about 300 mg KOH / g of polyols, between about 200 mg KOH / g of polyols and about 400 mg KOH / g of polyols or between about 300 mg KOH / g of polyols and 400 mg KOH / g of polyols. In yet another embodiment, the hydroxyl value of the polyether polyols used in the polyol blend for preparing a PUR / PIR foam is between approximately 400 mg KOH / g of polyols and approximately 600 mg KOH / g of polyols, or between approximately 300 mg KOH / g of polyols and approximately 500 mg KOH / g of polyols. Advantageously, the polyether polyols have a hydroxyl value between approximately 350 mg KOH / g and approximately 400 mg KOH / g of polyols, or between approximately 350 mg KOH / g of polyols and approximately 500 mg KOH / g of polyols.More specifically, the polyether polyols have a hydroxyl value of between approximately 350 mg KOH / g and approximately 390 mg KOH / g of polyols, preferably between approximately 350 mg KOH / g and approximately 360 mg KOH / g of polyols. In another embodiment, the hydroxyl value of the polyether polyols is between approximately 390 mg KOH / g and approximately 500 mg KOH / g of polyols, more specifically between approximately 390 mg KOH / g and approximately 470 mg KOH / g of polyols.

[0062] Polyether polyols can also be defined by their functionality and viscosity. Thus, polyether polyols included in the polyol blend for preparing a PUR / PIR foam have a functionality between 3 and 8, preferably between 3 and 6. The viscosity of the polyether polyols is less than 5000 rnPa·s at 25 °C, preferably less than or equal to 4000 rnPa·s at 25 °C. In one embodiment, the viscosity of the polyether polyols is between 2500 and 3000 rnPa·s at 25 °C. In another embodiment, the viscosity is less than 1500 mPa.s at 25 °C. In another embodiment, the viscosity of the polyether polyols is approximately 700 mPa.s at 25 °C.

[0063] In the context of the present technology, polyether polyols are glycerol-based polyols. More specifically, polyether polyols are glycerol- and carbohydrate-based polyols.

[0064] Examples of suitable carbohydrates for polyether polyols include sucrose, sorbitol, fructose, glucose, lactose, maltose, galactose, sorbose, xylose, arabinose, mannose, cellobiose, methyl glucoside, and mixtures thereof. In a preferred embodiment, the carbohydrate-based polyether polyols used in the polyol mixture for preparing a PUR / PIR foam are sucrose and / or sorbitol-based polyols.

[0065] Advantageously, the polyether polyols used in the polyol mixture for the preparation of a PUR / PIR foam are glycerol and sorbitol based polyols and / or glycerol and sucrose based polyols.

[0066] Such polyether polyols are commercially available. Examples include DALTOLAC® R404 marketed by Huntsman Corporation, MULTRANOL® 9260, MULTRANOL® 4030 and MULTRANOL® 4034 marketed by Bayer Corporation, THANOL® R-572 marketed by Arco Chemical, POLY G® 74-53 marketed by Olin Chemical, VORANOL® 202, VORANOL® 280, VORANOL® 360, VORANOL® 370, VORANOL® 490, VORANOL® 520, VORANOL® 615 and VORANOL® 800, marketed by Dow Chemicals Co, and RUBINOL® R180 and RUBINOL® R140 marketed by ICI Polyuréthanes.

[0067] The polyether polyols used in the polyol mixture for the foam formulation are the compounds preferentially marketed by Huntsman Corporation and Dow Chemicals Co. These are more particularly the compounds DALTOLAC® R404 and VORANOL® 360.

[0068] The polyether polyols used in the polyol mixture may be identical or different, and thus have identical or different intrinsic characteristics. In one embodiment, the polyether polyols are identical. In another embodiment, and advantageously, the polyether polyols are different.

[0069] Polyester polyols

[0070] In addition to polyether polyols, the polyol mixture according to the present technology includes polyester polyols.

[0071] In the context of the present technology, the polyether polyols have a molecular weight of between approximately 180 g / mol and approximately 4000 g / mol. In one embodiment, the molecular weight of the polyester polyols is less than or equal to approximately 3000 g / mol, less than or equal to approximately 2000 g / mol, or even less than or equal to approximately 1000 g / mol. In another embodiment, the molecular weight is greater than or equal to approximately 180 g / mol, or even greater than or equal to approximately 200 g / mol. Furthermore, in yet another embodiment, the polyether polyols have a molecular weight between approximately 200 g / mol and 900 g / mol, preferably between approximately 200 g / mol and approximately 800 g / mol, and more preferably between approximately 200 g / mol and approximately 700 g / mol. More specifically, the polyether polyols used in the polyol blend for preparing a PUR / PIR foam have a molecular weight between approximately 250 g / mol and approximately 600 g / mol, and preferably between approximately 250 g / mol and approximately 550 g / mol. Advantageously, the molecular weight of polyether polyols is between about 300 g / mol and about 550 g / mol, preferably between about 400 g / mol and about 550 g / mol.In another embodiment, the molecular weight of the polyether polyols is between about 420 g / mol and about 500 g / mol, between about 430 g / mol and about 500 g / mol, between about 450 g / mol and about 500 g / mol, and preferably between about 460 g / mol and about 490 g / mol.

[0072] In parallel, the polyester polyols used in the polyol mixture for the preparation of a PUR / PIR foam have a hydroxyl index of between about 100 mg KOH / g of polyols and about 400 mg KOH / g of polyols, preferably between about 150 mg KOH / g of polyols and about 400 mg KOH / g of polyols, more preferably between about 150 mg KOH / g of polyols and about 350 mg KOH / g of polyols. In another embodiment, the polyester polyols according to the present technology have a hydroxyl value of between about 200 mg KOH / g and about 350 mg KOH / g of polyols, preferably between about 200 mg KOH / g and about 300 mg KOH / g of polyols, more preferably between about 220 mg KOH / g of polyols and about 300 mg KOH / g of polyols.More specifically, the polyether polyols present in the polyol mixture have a hydroxyl value between approximately 220 mg KOH / g of polyols and approximately 270 mg KOH / g of polyols, between approximately 220 mg KOH / g of polyols and approximately 260 mg KOH / g of polyols, between approximately 220 mg KOH / g of polyols and approximately 250 mg KOH / g of polyols, or between approximately 230 mg KOH / g of polyols and 250 mg KOH / g of polyols.

[0073] Regarding the functionality of the polyester polyols included in the composition, this is between 1.5 and 5, preferably between 1.5 and 3. In one embodiment, the functionality of the polyester polyols is between 1.5 and 2.5. Advantageously, the polyester polyols have a functionality of 2.

[0074] As with polyether polyols, the viscosity of polyester polyols is less than 5000 mPa·s at 25 °C. In one embodiment, the viscosity is greater than or equal to 1000 mPa·s, or even greater than or equal to 2000 mPa·s. Advantageously, the viscosity of the polyether polyols used in the polyol blend for the pre The compressive strength of a PUR / PIR foam is between 2500 mPa.s and 4500 mPa.s at 25 °C, preferably between 2500 and 4000 mPa.s, and more preferably between 3000 and 4000 mPa.s at 25 °C.

[0075] The polyester polyols used in the polyol mixture may be identical or different.

[0076] From a structural point of view, the polyether polyols used in the polyol blend according to the technology and used in the preparation of a PUR / PIR foam are aromatic polyether polyols obtained by an esterification reaction of phthalic acid or phthalic anhydride. In one embodiment, the polyester polyols are aromatic polyester polyols, preferably derivatives of phthalic acid.

[0077] Examples of commercial polyester polyols are STEPANPOL® PS-2352, STEPANPOL® PS-1752, STEPANPOL® PS-3152 and STEPANPOL® PS-3024 marketed by Stepan Company.

[0078] In one embodiment, the polyester polyols used in the polyol blend are the STEPANPOL® compounds, and more particularly STEPANPOL® PS-2352.

[0079] Mixture of 3 different polyols

[0080] In the context of this technology, the polyol blend for preparing a PUR / PIR foam comprises a mixture of three (3) different polyols, said polyols being selected from the polyether polyols and polyester polyols previously defined. In one embodiment, the blend of three (3) different polyols comprises three (3) polyether polyols. In another embodiment, the blend of three (3) different polyols comprises two (2) polyether polyols and one (1) polyester polyol. In yet another embodiment, the blend of three (3) different polyols comprises one (1) polyether polyol and two (2) polyester polyols. In yet another embodiment, the blend of three (3) different polyols comprises three (3) polyester polyols. Advantageously, the mixture of three (3) different polyols according to the invention comprises two (2) polyether polyols and one (1) polyester polyol.

[0081] Advantageously, the mixture of three (3) different polyols thus comprises: a first polyether polyol having a molecular weight of between approximately 300 g / mol and approximately 600 g / mol, a hydroxyl value of between approximately 390 mg KOH / g and approximately 470 mg KOH / g of polyols, and a viscosity of less than 1500 mPa·s at 25 °C; a second polyether polyol having a molecular weight of between approximately 580 g / mol and approximately 600 g / mol, a hydroxyl value of between approximately 350 mg KOH / g and approximately 360 mg KOH / g of polyols, and a viscosity of less than or equal to 1500 mPa·s at 25 °C; and a polyester polyol defined by a molecular weight of between approximately 460 g / mol and approximately 490 g / mol, a hydroxyl value of between approximately 230 mg KOH / g of polyols and 250 mg KOH / g of polyols and a viscosity between 3000 and 4000 mPa.s at 25 °C.

[0082] Chain-extending polyols

[0083] The polyol blend for the PUR / PIR foam formulation further comprises a chain-extending polyol. The polyol blend therefore comprises: a mixture of three (3) different polyols selected from polyether polyols and polyester polyols, and a chain-extending polyol. Chain-extending polyols are functionalized compounds that can also act as crosslinking agents. These compounds generally have a molecular weight of less than 350 g / mol and contain from 2 to 14 carbon atoms.

[0084] In the context of the present technology, the chain-extending polyols have a molecular weight of between approximately 50 g / mol and approximately 300 g / mol, preferably between approximately 50 g / mol and approximately 250 g / mol, and more preferably between approximately 50 g / mol and approximately 200 g / mol. Advantageously, the chain-extending polyols have a molecular weight of between approximately 100 g / mol and approximately 150 g / mol. In a preferred embodiment, the chain-extending polyols have a molecular weight of approximately 134 g / mol.

[0085] The hydroxyl value of the chain-extending polyols used in the polyol mixture for preparing a PUR / PIR foam is between approximately 100 mg KOH / g of polyols and approximately 1000 mg KOH / g of polyols. In one embodiment, the chain-extending polyols have a hydroxyl value greater than or equal to approximately 200 mg KOH / g of polyols, preferably greater than or equal to approximately 300 mg KOH / g of polyols, and more preferably greater than or equal to approximately 500 mg KOH / g of polyols. In another embodiment, the hydroxyl index of the chain-extending polyols is between about 500 mg KOH / g of polyols and about 1000 mg KOH / g of polyols, preferably between about 600 mg KOH / g of polyols and about 1000 mg KOH / g of polyols, more preferably between about 700 mg KOH / g of polyols and about 1000 mg KOH / g of polyols.In yet another embodiment, the hydroxyl value of the chain-extending polyols included in the polyol mixture according to the present technology is between approximately 800 mg KOH / g of polyols and approximately 950 mg KOH / g of polyols, preferably between approximately 800 mg KOH / g of polyols and approximately 900 mg KOH / g of polyols. Advantageously, the chain-extending polyols have a hydroxyl value between approximately 800 mg KOH / g of polyols and approximately 850 mg KOH / g of polyols, preferably between approximately 820 mg KOH / g of polyols and approximately 850 mg KOH / g of polyols, and more specifically between approximately 830 mg KOH / g of polyols and approximately 850 mg KOH / g of polyols. In a preferred embodiment, the hydroxyl value of the chain-extending polyol is approximately 837 mg KOH / g of polyols.

[0086] An additional characteristic of chain-extending polyols is their functionality. Within the framework of the present technology, chain-extending polyols have a functionality of approximately 2. Advantageously, chain-extending polyols have a functionality of 2.

[0087] The viscosity of the chain-extending polyols is between 50 and 500 mPa·s at 25 °C, preferably between 100 and 300 mPa·s, and more preferably between 150 and 250 mPa·s. More precisely, the viscosity of the chain-extending polyols is between 175 and 225 mPa·s, and preferably between 190 and 210 mPa·s at 25 °C. Advantageously, the polyol blend for preparing a PUR / PIR foam comprises a chain-extending polyol with a viscosity of 200 mPa·s at 25 °C.

[0088] Examples of chain-extending polyols are bifunctionalized compounds such as diamines or diols, or trifunctionalized compounds such as triamines and triols. Examples include ethylene glycol, 1,2- and 1,3-propanediol isomers, 1,2- and 1,3-pentanediol isomers, 1,10-decanediol, 1,2-, 1,3- and 1,4-dihydroxycyclohexane isomers, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, bis(2-hydroxyethyl)hydroquinone, 1,2,4- and 1,3,5-tri-hydroxycyclohexane isomers, glycerol, trimethylolpropane, as well as low molecular weight polyalkylene oxide compounds comprising hydroxyl groups based on ethylene oxide and / or 1,2-propylene oxide and the compounds defined above.

[0089] In one embodiment, the chain-extending polyol used in the polyol mixture is a glycol-type derivative, in particular selected from ethylene glycol or propylene glycol derivatives. In a preferred embodiment, the chain-extending compound is dipropylene glycol.

[0090] Mixture of 4 polyols

[0091] The chain-extending polyol and the mixture of three (3) different polyols, said different polyols being chosen from polyether polyols and polyester polyols, thus define the mixture of polyols for the preparation of a PUR / PIR foam according to the present technology.

[0092] The polyol mixture for preparing a PUR / PIR foam comprises, in part by weight relative to the total weight of polyols:

[0093] - from approximately 20 pp to approximately 100 pp of polyether polyols, and preferably from approximately 10 pp to approximately 70 pp of a first polyether polyol and from approximately 10 pp to 40 pp of a second polyether polyol,

[0094] - from approximately 5 pp to approximately 50 pp of polyester polyols, and

[0095] - from about 10 pp to about 30 pp of chain-extending polyols.

[0096] In another embodiment, the polyol mixture comprises:

[0097] - from approximately 28 to approximately 100 pp of polyether polyols, and preferably approximately 18 to 67 pp of a first polyether polyol and approximately 10 to 25 pp of a second polyol,

[0098] - from approximately 5 pp to approximately 40 pp of polyester polyols, and

[0099] - from about 15 pp to about 30 pp of chain-extending polyols.

[0100] Preferably, the polyol mixture comprises:

[0101] - of approximately 65 to approximately 80 pp of polyether polyols, and preferably of approximately 44 to 55 pp of a first polyether polyol and approximately 15 to 25 pp of a second polyol,

[0102] - from approximately 20 pp to approximately 35 pp of polyester polyols, and

[0103] - from about 15 pp to about 25 pp of chain-extending polyols.

[0104] More preferably, the polyol mixture comprises:

[0105] - of approximately 65 to approximately 80 pp of polyether polyols, and preferably of approximately 48 to 55 pp of a first polyether polyol and approximately 17 to 23 pp of a second polyol,

[0106] - from approximately 25 pp to approximately 32 pp of polyester polyols, and

[0107] - from about 18 pp to about 25 pp of chain-extending polyols.

[0108] Advantageously, the polyol blend comprising three (3) different polyols and one chain-extending polyol, said different polyols being selected from polyether polyols and polyester polyols, comprises, in part by weight relative to the total weight of polyols:

[0109] - approximately 70 pp of polyether polyols,

[0110] - approximately 30 pp of polyester polyols, and

[0111] - approximately 20 pp of chain-extending polyols

[0112] More specifically, the polyol mixture comprises, in part by weight relative to the total weight of polyols:

[0113] - approximately 50 pp of a first polyether polyol,

[0114] - approximately 20 pp of a second polyether polyol,

[0115] - approximately 30 pp of polyester polyols, and

[0116] - approximately 20 pp of chain-extending polyols.

[0117] In another embodiment, the polyol blend for preparing a PUR / PIR foam comprises, as a mass percentage relative to the total weight of polyols:

[0118] - about 20 to about 85% polyether polyols, and preferably about 30 60% of a first polyether polyol and approximately 5 to approximately 40% of a second polyether polyol,

[0119] - approximately 10 to approximately 50% polyester polyols, and

[0120] - about 5 to about 35% chain-extending polyols.

[0121] In another embodiment, the mixture of polyols for the preparation of a PUR / PIR foam comprises, as a mass percentage relative to the total weight of polyols:

[0122] - about 30 to about 70% polyether polyols, and preferably about 35 50% of a first polyether polyol and approximately 10 to approximately 35% of a second polyether polyol,

[0123] - approximately 15 to approximately 35% polyester polyols, and

[0124] - about 10 to about 25% chain-extending polyols.

[0125] In another embodiment, the polyol blend for preparing a PUR / PIR foam comprises, as a mass percentage relative to the total weight of polyols:

[0126] - about 40 to about 60% polyether polyols, and preferably about 35 50% of a first polyether polyol and approximately 10 to approximately 25% of a second polyether polyol,

[0127] - approximately 20 to approximately 30% polyester polyols, and

[0128] - about 15 to about 25% chain-extending polyols.

[0129] Advantageously, the polyol mixture comprises, as a mass percentage relative to the total weight of polyols:

[0130] - about 58% polyether polyols, and preferably about 42% of a first polyether polyol and approximately 16% of a second polyether polyol,

[0131] - approximately 24% polyester polyols, and

[0132] - approximately 18% chain-extending polyols.

[0133] The resulting polyol blend, comprising three (3) different polyols and one chain-extending polyol, the different polyols being selected from polyester polyols and polyether polyols, has a viscosity of less than 5000 mPa·s at 25°C, preferably less than 1000 mPa·s at 25°C, and more preferably less than or equal to 900 mPa·s at 25°C. In another embodiment, the viscosity of the polyol blend is equal to or greater than 200 mPa·s, preferably equal to or greater than 300 mPa·s, and more preferably equal to or greater than 400 mPa·s at 25°C. Furthermore, in yet another embodiment, the polyol blend has a viscosity between 400 and 900 mPa·s at 25°C. Advantageously, the polyol mixture according to the present technology and used for the composition of a PUR / PIR foam has a viscosity between 400 and 800 mPa.s at 25 °C, preferably between 500 and 800 mPa.s, and more preferably between 600 and 800 mPa.at 25 °C. In another embodiment, the viscosity of the polyol mixture is 750 mPa.s at 25 °C.

[0134] Composition of the PUR / PIR foam

[0135] The polyol mixture comprising three (3) different polyols and one chain-extending polyol, the different polyols being selected from polyester polyols and polyether polyols, can be used for the preparation of a PUR / PIR foam.

[0136] PUR / PIR foam is an alveolar structure composed of fine, closed cells enclosing a gas. The formation of PUR / PIR foams is well known to those skilled in the art and involves a multi-component reaction between one or more polyols, one or more polyisocyanates, and a blowing agent, also known as a blowing agent. This condensation reaction can be catalyzed by basic and / or nucleophilic compounds such as tertiary amines, organometallic complexes, or alkali metal complexes.

[0137] Thus, the composition of the PUR / PIR foam according to the present technology comprises a mixture of polyols comprising three (3) different polyols and a chain-extending polyol, as defined above, and at least one polyisocyanate compound and a catalyst.

[0138] Polyisocyanate compounds

[0139] Polyisocyanate compounds are characterized by the presence of at least two isocyanate groups (-NCO) within their molecular structure.

[0140] The polyisocyanate compounds suitable for the composition of a PUR / PIR foam are known to those skilled in the art. Polyisocyanate compounds include aromatic, aliphatic, cycloaliphatic, arylaliphatic polyisocyanates and mixtures thereof.

[0141] Within the framework of the present technology, polyisocyanate compounds are diisocyanate compounds, i.e. comprising two isocyanate groups, and may be aliphatic or aromatic.

[0142] Polyisocyanate compounds have a viscosity between 100 and 3000 mPa.s at 25 °C. The polyisocyanates used in the composition of PUR / PIR foam have a viscosity less than or equal to 2000 mPa.s, or even less than 1000 mPa.s. In one embodiment, the polyisocyanates have a viscosity between 200 and 1000 mPa.s, preferably between 200 and 800 mPa.s, more preferably between 200 and 600 mPa.s at 25 °C.

[0143] The functionality of the polyisocyanate compound is between 2.5 and 3.5, and is advantageously between 2.7 and 3.1.

[0144] Suitable diisocyanate compounds for the invention are hexamethylene diisocyanate (HDI), isophore diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate (CHDI), Zα(iscocyanatomethyl)cyclohexane (H6XDI,DDI), m-xylene diisocyanate (m-XDI), tetramethylxylylene diisocyanate (TMXDI), toluene diisocyanate (TDI) compounds such as the 2,4- and 2,6-toluene diisocyanate isomers (2,4-TDI and 2,6-TDI), and diphenylmethylene diisocyanate (MDI) compounds such as the 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (2,4'-MDI, 2,4'-MDI and 2,2'-MDI), and dibenzyl diisocyanate compounds, such as the 4,4'- and 2,2'-MDI isomers 2,4'-dibenzyl düsocyanate (4,4'-DBDI and 2,4'-DBDI).

[0145] In one embodiment of the present technology, the polyiscoyanate compound is an aromatic düsocyanate compound, preferably selected from toluene düsocyanate (TDI) compounds, diphenylmethylene düsocyanate (MDI) compounds, and dibenzyl düsocyanate (DBDI) compounds. Advantageously, the dü-socyanate compound is selected from methylene diphenyl (MDI) düsocyanate compounds.

[0146] Düsocyanate compounds may possibly be obtained commercially. Examples of such compounds are VORANATE®, VORACOR®, such as VORACOR® CL100 or VORACOR® CE101, or PAPI® such as PAPI® 27, available from Dow Chemical Co and SUPRASEC® S5005, SUPRASEC® S2085 available from Huntsman and LUPRANATE® M20 and LUPRANATE® M50 available from BASF.

[0147] It is understood within the framework of the present technology that the dusocyanate compound may be a mixture of several dusocyanate compounds as defined above.

[0148] The presence of the polyisocyanate compound is essential for foam formation in addition to the polyol mixture. The amount of polyisocyanate is thus at least approximately 70 pp per 100 pp of polyols. In one embodiment, the amount of polyisocyanate is between approximately 70 pp and approximately 140 pp, preferably between approximately 80 pp and approximately 130 pp, more preferably between approximately 83 pp and approximately 128 pp per 100 pp of polyols. Advantageously, the amount of polyisocyanate is between approximately 85 pp and approximately 125 pp, preferably between approximately 87 pp and approximately 123 pp, more preferably between approximately 90 pp and approximately 120 pp per 100 pp of polyols.

[0149] In another embodiment, the amount of polyisocyanates is between approximately 80% and approximately 200% by weight relative to the total weight of polyols. In one embodiment, the amount of polyisocyanates is between approximately 90% and approximately 180%, preferably between approximately 100% and approximately 150%. In another embodiment, the amount of polyisocyanates in the PUR / PIR foam composition is between approximately 100% and approximately 140%, preferably between approximately 110% and approximately 130%, more preferably between approximately 115% and 125%, by weight relative to the total weight of polyols. Advantageously, the foam according to the present technology comprises between about 117% and 123% polyisocyanates, preferably between about 118% and about 122%, and more preferably between about 119% and about 121% by weight relative to the total weight of polyols.

[0150] The quantity of isocyanate compound can also be defined by the isocyanate / polyol ratio. Examples of isocyanate / polyol ratios according to the present technology include 1:1 and 1.8:1. In the context of the present invention, the foams obtained are PUR / PIR type foams and have an isocyanate / polyol ratio of between 1 and 1.25.

[0151] Catalysts

[0152] The term “catalyst” means any compound that accelerates the polymerization or condensation reaction between polyols and polyisocyanates.

[0153] In general, all compounds that can catalyze the reaction between polyols and polyisocyanates can be used.

[0154] The catalysts may be gelling, expansion, hardening, or trimerization catalysts commonly used in the preparation of PIR foams. Reference may be made to the compounds described in “Kunststoffhandbuch, volume 7, Polyuréthane”, Cari Hanser Verlag, 3rd edition, 1993, chapter 3.4.1.

[0155] Within the framework of the present technology, the catalysts are chosen from among organometallic catalysts, and in particular from among stannic or tin-based catalysts, bismuth-based catalysts and alkali metal carboxylates.

[0156] In one embodiment, the catalysts are selected from tin(II) carboxylates, such as tin acetate, tin octoate, tin ethylhexanoate, tin laurate, and tin(IV) carboxylates, such as tin dibutyl diacetate, tin dibutyl dilaurate (DBTDL), tin dibutyl maleate, tin dioctyl diacetate.

[0157] In another embodiment, the catalysts used in the composition of a PUR / PIR foam are bismuth-based catalysts, in particular bismuth carboxylates, bismuth alkanolamines, or bismuth thiolates. Examples of such compounds are bismuth neodecanoate, bismuth 2-ethylhexanoate, and bismuth octanoate.

[0158] In yet another embodiment, the catalysts used are alkali metal carboxylates, preferably potassium carboxylates such as potassium acetate, potassium formate, or potassium octanoate. Advantageously, the catalyst is potassium octanoate.

[0159] In another embodiment, the catalyst is a mixture of catalysts, preferably a mixture comprising a tin-based catalyst and an alkali metal carboxylate. Thus, in another embodiment, the mixture comprises a tin catalyst and potassium octanoate.

[0160] Thus, the catalyst entering into the composition of the PUR / PIR foam is chosen from among stannic catalysts, potassium carboxylates or a mixture of these.

[0161] Commercial catalysts can also be used in the composition of PUR / PIR foam, such as POLYCAT® type catalysts marketed by Evonik Industries, and more specifically POLYCAT® 5, POLYCAT® 9, POLYCAT® 203, or KOSMOS® type catalysts, such as KOSMOS® T12N, marketed by Evonik Industries.

[0162] Expansion agents

[0163] The composition of the PUR / PIR foam further comprises an expanding or blowing agent. This element enables the creation of a foam-like alveolar structure and may be of a physical and / or chemical nature. Advantageously, the expanding agent consists of a combination of both.

[0164] Physical blowing agents are well known to those skilled in the art, and include hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) or hydrofluoroolefins (HFOs).

[0165] Examples of hydrochlorofluorocarbons are HCFC-123 (2,2-dichloro-l,l,l-trifluoroethane) and HCFC-141b (1,1-dichloro-l-fluoroethane).

[0166] Thus, in one embodiment of the invention, the blowing agent is chosen from among hydrofluorocarbons (HFCs), such as HFC-245fa (1,1,1,3,3-pentafluoropropane), HFC-365mfc (1,1,1,3,3-pentafluorobutane, HFC-134a (1,1,1,2-tetrafluoroethane) and HFC-152a (1,1-difluoroethane) or hydrofluorolefins (HFOs) such as HFO-1234yf (2,3,3,3-tetrafluoropropene), HFO-1234ze (1,3,3,3-tetrafluoropropene) or HFO-1233zd (l-chloro-3,3,3-trifluoropropene).

[0167] In another embodiment, the blowing agent is a chemical agent, and more particularly carbon dioxide (CO2) and / or water. Indeed, the presence of water as a blowing agent induces the release of CO2, which causes the foam to expand. The preferred chemical blowing agent is water.

[0168] Physical and chemical blowing agents can be used individually or simultaneously. According to one embodiment of the invention, the blowing agent comprises a physical agent and a chemical agent. Thus, in one embodiment, the blowing agent is a mixture comprising a hydrofluorocarbon (HFC), a hydrofluoroolefin (HFO), and / or carbon dioxide (CO2), wherein the hydrofluorocarbon and hydrofluoroolefin compounds are selected from the compounds mentioned above. In another embodiment, the blowing agent is a mixture comprising HCF-365mfc and / or HCF-245fa combined with water.

[0169] The formulation of the PUR / PIR foam according to the invention may include one or more expanding agents.

[0170] In one embodiment, the composition includes a blowing agent selected from water, CO2, the previously defined fluorinated blowing agents or a mixture thereof.

[0171] The amount of the physical blowing agent is calculated based on the density of the PUR / PIR foam. It is preferably between 0 and approximately 10% by weight relative to the total weight of polyols. In one embodiment, the amount of the blowing agent is between approximately 2% and approximately 10%, preferably between approximately 5% and approximately 10% by weight relative to the total weight of polyols. Advantageously, the amount of blowing agent in the PUR / PIR foam composition is approximately 7% by weight relative to the total weight of polyols.

[0172] The quantity of water also depends on the characteristics of the desired foam density. According to the invention, it is preferably between 0 and about 1%, preferably between 0 and about 0.5%, and even more preferably between 0 and about 0.2% by weight relative to the total weight of polyols.

[0173] Flame retardants

[0174] PUR / PIR foams generally include flame retardants in their composition to limit flammability and increase the fire resistance of said foam. Flame retardants are well known to those skilled in the art and are described in "Kunststoffhandbuch", Volume 7, "Polyurethane", Chapter 6.1.

[0175] Compounds used as flame retardants include: brominated compound Ixol®B251, dibromonopentyl alcohol, tribromonopentyl alcohol, tetrabromophthalate diol known as PHT4-diol™, chlorinated phosphate compounds such as tris(chloropropyl)phosphate (TCPP), tris(2-chloroethyl)phosphate (TCEP), tris(2-chloroisopropyl)phosphate (TCCP) and tris(1,3-dichloroisopropyl)phosphate (TDCPP).

[0176] It is also possible to use inorganic flame retardants, such as phosphorus or preparations comprising phosphorus, expandable graphite, hydrated aluminium oxide, antimony trioxide, ammonium polyphosphate, calcium sulfate or derivatives of cyanuric acid such as melamine or mixtures of at least two flame retardants such as ammonium phosphate and melamine.

[0177] Other halogen-free liquid flame retardants can also be cited, such as diethylmethane phosphate (DEEP), triethyl phosphate (TEP), dimethylpropyl phosphate (DMPP) or diphenylcresyl phosphate (DPC).

[0178] In one embodiment, the composition of the foam includes a flame retardant, advantageously with an amount between 5% and 20% by weight relative to the total weight of polyols.

[0179] In another embodiment, the formulation does not include a flame retardant. According to a preferred embodiment of the invention, the formulation does not include any flame retardant.

[0180] Additives

[0181] The formulation may also include other commonly used additives in the preparation of PUR / PIR foams, such as surfactants, stabilizers, emulsifiers, plasticizers, colorants or crosslinking agents.

[0182] In one embodiment, the foam composition includes at least one additive, preferably a surfactant.

[0183] In one embodiment, the formulation comprises at least one surfactant. Surfactants, also called surface-active agents or emulsifiers, are compounds that modify the surface tension between two surfaces. Their role is thus to solubilize at least two immiscible phases. In the context of the present technology, the composition of the PUR / PIR foam may comprise one or more surfactants. These compounds may be silicone-based or non-silicone-based, or a mixture thereof. Examples of silicone surfactants suitable for PUR / PIR foam formulations are TEGOSTAB® B-8427, B-2454, B-8404, B-8407, B-8409, B-8462, B-8465, B-8315, B-1048 and B-84507 marketed by Evonik, L-5130, L-5180, L-5340, L-5440, L-6100, L-6900, L-6980 and L-6980 marketed by MOMENTIVE and DC-5374, DC-193, DC-197, DC-5582, and DC-5598 marketed by DOW CORNING.Examples of non-silicone surfactants include oxyethylated alkyl phenol compounds, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, peanut oil, and fatty alcohols.

[0184] Properties of PUR / PIR foam

[0185] The composition of the PUR / PIR foam, comprising the polyol mixture, a catalyst, one or more blowing agents, and optionally one or more additives, is particularly suitable for ensuring that, in liquid form, the foam is distributed homogeneously. "Homogeneous distribution" means the foam is distributed equally or uniformly over the entire substrate or surface onto which the liquid composition is deposited before expansion. Once the foam is obtained, it exhibits homogeneous or equivalent thermal and mechanical properties at every point within the material.

[0186] The foam thus possesses particular physical and chemical characteristics, as well as particular mechanical properties due in particular to its composition.

[0187] Examples of physical and chemical properties include thermal conductivity, density, and compressive strength.

[0188] In liquid form, or more precisely in emulsion form, the foam exhibits interesting stability with a creaming time of approximately sixty (60) seconds. The creaming time can be defined as the time between the start of the mixing phase of all the ingredients and the moment when the first bubbles appear, a change in the composition's color is observed, or when the mixture expands to become a foam. The creaming time is defined according to the ASTM D7487 standard.

[0189] Once formed, the foam has a density of less than 150 kg / m³, or even less than 140 kg / m³. In one embodiment, the density of the resulting foam is between 90 and 140 kg / m³, preferably between 100 and 140 kg / m³, and more preferably between 110 and 130 kg / m³. In another embodiment, the PUR / PIR foam produced according to the present technology has a density of between 115 and 125 kg / m³, preferably between 116 and 122 kg / m³, and more preferably between 118 and 122 kg / m³. In a preferred embodiment, the PUR / PIR foam has a density of approximately 120 kg / m³.

[0190] In parallel, the PUR / PIR foam has a thermal conductivity of less than 30 mW / mK, or even less than 27 mW / mK. Thermal conductivity indicates the foam's ability to diffuse heat. Thus, the lower the conductivity, the more insulating the foam. In one embodiment, the thermal conductivity is between 20 and 27 mW / mK, preferably between 22 and 26 mW / mK, more preferably between 23 and 26 mW / mK. More precisely, the thermal conductivity of the foam according to the invention is between 24 and 26 mW / mK. In another embodiment, the PUR / PIR foam has a thermal conductivity of approximately 25 mW / mK.

[0191] Regarding mechanical properties, the foam obtained can be characterized by compressive stress, compressive modulus of elasticity, tensile or shear strength, flexural strength, etc.

[0192] Compressive stress defines the ability of the foam to resist an applied compressive load, that is to say an external load applied to the foam in order to obtain its deformation and / or size.

[0193] In the context of this technology, the PUR / PIR foam has a compressive strength greater than 1.10 MPa, or even greater than 1.20 MPa. In one embodiment, the compressive strength of the foam is between 1.20 and 1.60 MPa, preferably between 1.30 and 1.60 MPa, and more preferably between 1.30 and 1.50 MPa. Advantageously, the compressive strength of the PUR / PIR foam is between 1.40 and 1.50 MPa according to ISO 844.

[0194] Method for manufacturing a block of PUR / PIR foam

[0195] After expansion of the liquid composition of the previously defined PUR / PIR foam, a PUR / PIR foam is obtained.

[0196] PUR / PIR foam is the result of a physicochemical process in which the polyol mixture reacts with polyisocyanates. The reaction can be described as a polymerization or condensation reaction. The exothermic reaction releases carbon dioxide, which causes the foam to swell.

[0197] The process for manufacturing a block of PUR / PIR foam according to the present The technology thus includes the following steps: i. bringing into contact at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and one chain-extending polyol, said polyols being selected from polyether polyols and polyester polyols, in the presence of catalysts, blowing agents and optionally additives and flame retardant, ii. deposit the foam composition obtained in step (i) onto a support, and iii. Allow the said composition to solidify after expansion so as to form a block of foam.

[0198] Thus, in a first step, at least one polyisocyanate compound is brought into contact with the polyol mixture consisting of three different polyols and a chain-extending polyol in the presence of catalysts, blowing agents, and possibly additives. The mixing is preferably carried out at ambient temperature and with a low- or high-pressure machine. Low- and high-pressure machines are well known to those skilled in the art, who will be able to determine the appropriate machine based on the composition and characteristics of the foam.

[0199] The mixture obtained, corresponding to the composition of the PUR / PIR foam according to the present technology, is then rapidly poured onto a support so that the composition is distributed homogeneously over the entire support.

[0200] The PUR / PIR foam composition, initially in liquid form, is transformed into foam via a chemical reaction. This foam expansion step can be free or forced.

[0201] In one embodiment, the expansion is said to be free, that is to say, no constraint exerted by a closed cross-sectional volume is applied. In another embodiment, the expansion of the foam is physically constrained by the walls of a double-belt laminator, preferably a double-belt laminator forming a tunnel with a rectangular cross-section and a distance between the laterally dispersed walls equal to L and a distance between the horizontally arranged walls equal to E, thus enclosing the expanding foam so as to obtain the foam block with defined dimensions.

[0202] The foam is then allowed to solidify. This final hardening or solidification stage can be carried out at elevated temperatures or at room temperature.

[0203] It is understood that where the foam block is prepared by free expansion, it is possible to cut the foam block to obtain a foam block whose dimensions and shape conform to the desired characteristics. This deburring step can be carried out before or after solidification of the foam block.

[0204] In one embodiment, and preferably, the casting step is carried out on a support which is a reinforcing material such as a stack of glass fibers or glass mats, in order to obtain a block of fiber-reinforced foam. The process then comprises the following steps: i. bringing into contact at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and one chain-extending polyol, said polyols being selected from polyether polyols and polyester polyols, in the presence of catalysts, blowing agents and optionally additives and flame retardant, ii. deposit the foam composition obtained in step (i) onto a stack of glass fibers or glass mats, and iii. allow said composition to solidify after expansion so as to form a block of foam.

[0205] In this case, the PUR / PIR foam composition is poured onto the reinforcing material so that the formulation permeates the entire thickness of the glass fiber or glass fiber mat stack. The glass fiber or glass mat content can be determined, in particular, according to ISO 1172.

[0206] A particular advantage of the composition of the foam is that it penetrates the reinforcing materials quickly and uniformly.

[0207] The fiberglass mats preferably used are continuous strand mats, notably marketed under the Unifilo® or Advantex® brand by Owens Corning.

[0208] These glass fibers are bonded together by a binder preferably present in a content ranging from approximately 0.6 to approximately 3% by mass relative to the total mass of the glass fiber mat, and preferably approximately 2.5%. The binder used for sizing the glass fibers is preferably an epoxy resin.

[0209] The glass fibers constituting the mats preferably used have a linear mass of 20 to 40 Tex, i.e. 20 to 40 g / km of fibers.

[0210] The glass fiber mats preferably have a surface mass between 300 and 900 g / m² and more advantageously between 300 and 600 g / m², more preferably around 450 g / m². The glass fibers preferably constitute 6 to 12% by mass relative to the total mass of the reinforced PUR / PIR foam. Advantageously, the glass fibers constitute approximately 10% by mass of the PUR / PIR foam relative to its total mass.

[0211] Depending on the amount of binder and the surface mass of the glass fiber mats, and in order to obtain acceptable mechanical properties, the number of glass fiber mats varies from 4 to 12.

[0212] Glass fibers preferably used according to a second embodiment They are advantageously manufactured from roving, that is, a more or less wide and flattened ribbon made of glass fibers that are not twisted but held parallel to each other. The glass fibers are preferably deposited using the "Webforming" process of Plastech TT Ltd.

[0213] The glass fibers deposited by this process preferentially have a linear mass of 30 to 300 Tex.

[0214] Use of PUR / PIR foam

[0215] PUR / PIR foams have versatile applications thanks to their insulating and adhesive properties. PUR / PIR foams, according to the technology, are stable, have low thermal conductivity, and exhibit excellent mechanical properties such as shear strength, compressive strength, and Young's modulus. Furthermore, the foams exhibit a homogeneous distribution throughout the reinforcing material. According to the invention, the foams are particularly well-suited for thermal insulation, and more specifically for insulating tanks for transporting liquefied gases, such as liquefied petroleum gas (LPG), liquefied natural gas (LNG), or tanks for transporting cold liquid products such as ammonia or hydrogen, used in LNG carriers.The invention can also be used for the insulation of pipes or storage tanks in ships, or for land-based or port-based pipes and storage tanks.

[0216] In another embodiment, PUR / PIR foams according to the invention are used for the formation of insulating panels.

[0217] The composition, comprising the polyol mixture, at least one polyisocyanate compound, the catalyst, and optionally additives, is deposited onto a surface to form a foam block. The deposition rate is calculated based on the desired foam block height and density. Those skilled in the art will be able to determine these parameters.

[0218] After expansion and solidification of said foam, the lateral, upper and / or lower parts of the foam block are removed. This deburring step makes it possible to obtain foam blocks of determined dimensions.

[0219] These PUR / PIR foam blocks can also be cut transversely at one-third of their thickness to form the two primary and secondary insulation layers. This single cutting step from a single foam block thus makes it possible to obtain a primary and a secondary insulation layer simultaneously, resulting in material savings due to minimal waste, and time savings since only one step is required to produce two layers of thermal insulation. EXAMPLES

[0220] Example 1 - Example of composition of a polyurethane / polyisocyanurate foam according to one aspect of the present technology

[0221] [Tables 1] Compound Quantity (in pp) Quantity per 100 pp of polyols (in pp) Polyol Daltolac® R404 50 42 Stepanpol® PS 2352 30 24 DPG Dipropylene glycol 20 18 Voranol® 360 RH 20 16 Catalyst T 12 / 10 0.1 0.1 Surfactant B8465 2 1 Blowing agent 365mfc 10 8 ISO S5005 150 120 REFERENCES

[0222] -US 2010 / 0116829

[0223] - US 8,940,803

[0224] - WO 2020 / 104749

[0225] .

Claims

Demands

1. Polyol mixture for the preparation of a polyurethane / polyisocyanurate (PUR / PIR) foam, characterized in that the polyol mixture comprises three (3) different polyols and one chain-extending polyol, said different polyols being selected from poly-ether polyols and polyester polyols, and the polyol mixture having a viscosity of less than 1000 mPa.s at 25 °C.

2. Mixture of polyols according to claim 1, characterized in that the polyether polyols are glycerol and sorbitol based polyols and / or glycerol and sucrose based polyols.

3. A mixture of polyols according to any one of claims 1 or 2, characterized in that the polyester polyols are aromatic polyester polyols, preferably phthalic acid derivatives.

4. A mixture of polyols according to any one of claims 1 to 3, characterized in that the chain-extending polyol is a glycol-type derivative, preferably of dipropylene glycol.

5. A mixture of polyols according to any one of claims 1 to 4, characterized in that the mixture has a viscosity between 400 and 800 mPa.s at 25 °C

6. V-. Mixture of polyols according to any one of claims 1 to 5, characterized in that it comprises: - 28 pp to 100 pp of polyether polyols, and 18 pp to 67 pp of a first polyether polyol and 10 pp to 25 pp of a second polyether polyol, - 5 pp to 40 pp of a polyester polyol, and - 15 pp to 30 pp of a chain-extending polyol.

7. Composition of a PUR / PIR foam, characterized in that the composition comprises: - the mixture of polyols according to any one of claims 1 to 6, - at least one polyisocyanate compound, and - a catalyst.

8. Composition according to claim 7, characterized in that the composition comprises between 90 pp and 120 pp of polysiocyanate for 100 pp of polyols.

9. Composition according to claim 7 or 8, characterized in that the polyisocyanate is selected from aromatic diisocyanates, preferably, the isocyanate compound is methylene diisocyanate

10.

11.

12.

13.

14.

15.

16.

17.

18. diphenyl (MDI). Composition according to any one of claims 7 to 9, characterized in that the catalyst is selected from stannic catalysts and potassium carboxylates, or a mixture thereof. Composition according to any one of claims 7 to 10, characterized in that the composition further comprises a blowing agent selected from water, CO2 and fluorinated blowing agents, or a mixture thereof. Composition according to any one of claims 7 to 11, characterized in that it further comprises one or more additives. Polyurethane / polyisocyanurate foam obtained from the composition defined in claims 7 to 12. Polyurethane / polyisocyanurate foam according to claim 13, characterized in that said foam has a density between 110 and 130 kg / m3. Polyurethane / polyisocyanurate foam according to claim 13 or 14, characterized in that said foam has a thermal conductivity between 24 and 26 mW / mK Polyurethane / polyisocyanurate foam according to any one of claims 13 to 15, characterized in that said foam has a compressive stress between 1.30 and 1.50 MPa. A process for manufacturing a polyurethane / polyisocyanurate foam according to claims 13 to 16, said process comprising the steps of: i. bringing into contact at least one polyisocyanate compound and the polyol mixture comprising three (3) different polyols and a chain-extending polyol as defined in claims 1 to 6, in the presence of catalysts, blowing agents and optionally flame retardant and additives, and ii. deposit the foam composition obtained in step (i) onto a stack of glass fibers or glass mats, and iii. allow said formulation to solidify after expansion so as to form a block of foam. Use of polyurethane / polyisocyanurate foam according to claims 13 to 16, or obtained according to the process defined in claim 17 for thermal insulation.