Polyurethane / polyisocyanurate foam formulations

Abstract

The present invention relates to polyol mixtures comprising three (3) different polyols and a chain extender polyol. The mixture is used to produce polyurethane / polyisocyanurate (PUR / PIR) foams when reacted with at least one polyisocyanate compound in the presence of a catalyst, a blowing agent and optionally other additives. The invention also relates to a PUR / PIR foam composition, a method for obtaining the foam and the foam obtained thereby. The PUR / PIR foams have advantageous physical properties and characteristics, in particular in terms of density, mechanical strength and thermal conductivity.

Description

Technical Field

[0001] The present technology relates to a polyol mixture for preparing polyurethane / polyisocyanurate (PUR / PIR) foams. The mixture comprises three (3) different polyols and a chain extender polyol. The mixture enables to obtain PUR / PIR foams which are particularly suitable for use as thermal insulation materials. The present technology also relates to a composition for formulating said PUR / PIR foams, the foams obtained and a method for obtaining said foams. Background Art

[0002] Polyurethanes or polymers consisting of one or more urethane molecules are well known to those skilled in the art and are currently used in many areas as insulating materials, adhesives or as compounds in the automotive, textile or furniture industries.

[0003] Polyurethanes are used more particularly in the form of foams: polyurethane (PUR) foams, polyisocyanurate (PIR) foams 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, the amounts used and the presence of additives make it possible to obtain polyurethane foams having different properties and properties, which are specific to each composition.

[0004] Polyurethane PUR foams can be used in the automotive industry as flexible foams or as rigid foams for thermal insulation. PUR / PIR and PIR foams can also be used as thermal insulation. These foams have the advantage of better fire resistance and higher compressive strength than PUR foams.

[0005] PUR, PIR and PUR / PIR foams are classified according to their isocyanate / polyol ratio. The formation mechanism of PIR foam and PUR / PIR foam is similar to that of PUR foam.

[0006] A large number of compositions for formulating PUR / PIR foams are described in the prior art, including patent applications US2010 / 0116829 and WO2020 / 104749 or patent application US8940803.

[0007] However, no composition makes it possible to obtain a foam having simultaneously a good thermal coefficient, satisfactory mechanical properties and conformity with industry specifications, and a foam composition having a viscosity that allows for a uniformly distributed foam.

[0008] The inventors have thus discovered a composition for formulating polyurethane foams which solves at least some of the deficiencies hitherto found in this technical field. Summary of the invention

[0009] The present technology relates to a polyol mixture, characterized in that the polyol mixture includes three (3) different polyols and a chain extender polyol, wherein the different polyols are selected from polyether polyols and polyester polyols. The mixture is used to formulate polyurethane / polyisocyanurate (PUR / PIR) foam, and the foam composition comprises the polyol mixture, at least one polyisocyanate compound and a catalyst.

[0010] The present technology relates to a polyol mixture, characterized in that the polyether polyol is a polyol based on glycerol and sorbitol and / or a polyol based on glycerol and sucrose.

[0011] The present technology relates to a polyol mixture, characterized in that the polyester polyol is an aromatic polyester polyol, preferably a phthalic acid derivative.

[0012] The present technology relates to a polyol mixture, characterized in that the chain extender polyol is a diol derivative, preferably dipropylene glycol.

[0013] The present technology relates to a polyol mixture, characterized in that the mixture has a viscosity between 400 and 800 mPa.s at 25°C.

[0014] The present technology relates to a polyol mixture, characterized in that the polyol mixture comprises:

[0015] 28 pw to 100 pw of a polyether polyol, and 18 pw to 67 pw of a first polyether polyol, and 10 pw to 25 pw of a second polyether polyol;

[0016] 5 pw to 40 pw of polyester polyol; and

[0017] 15 pw to 30 pw of chain extender polyol. The present technology therefore also relates to foam compositions further comprising a blowing agent and an additive.

[0018] The present technology therefore also relates to a composition of PUR / PIR foam, characterized in that the composition comprises:

[0019] a polyol mixture as defined in the art comprising three (3) different polyols and a chain extender polyol;

[0020] at least one polyisocyanate compound; and

[0021] catalyst.

[0022] The present technology therefore also relates to a composition of PUR / PIR foams, characterised in that the composition comprises between 90 pw and 120 pw of polyisocyanate per 100 pw of polyol.

[0023] The present technology therefore also relates to a composition of PUR / PIR foam, characterized in that the polyisocyanate is selected from aromatic diisocyanates; preferably, the isocyanate compound is methylene diphenyl diisocyanate (MDI).

[0024] The present technology therefore also relates to a composition of PUR / PIR foams, characterized in that the catalyst is selected from tin catalysts and potassium carboxylates, or mixtures thereof.

[0025] The present technology therefore also relates to a composition of PUR / PIR foam, characterized in that the composition further comprises a blowing agent selected from water, CO2 and a fluorinated blowing agent, or a mixture thereof.

[0026] The present technology therefore also relates to a composition of PUR / PIR foam, characterized in that the composition further comprises one or more additives.

[0027] Another subject of the present technology is the obtained PUR / PIR foam, which has the following characteristics: 3 and 130kg / m 3 a density between 1.00 and 2.00 MPa, a thermal conductivity between 24 mW / mK and 26 mW / mK, and / or a compressive strength between 1.30 MPa and 1.50 MPa.

[0028] Another subject of the present technology is a PUR / PIR foam obtained from the composition defined above.

[0029] Another subject of the present technology is a PUR / PIR foam, characterized in that the foam has a relative humidity between 110 and 130 kg / m 3 The density between.

[0030] Another subject matter of the present technology is a PUR / PIR foam, characterised in that it has a thermal conductivity between 24 and 26 mW / mK.

[0031] Another subject matter of the present technology is a PUR / PIR foam, characterised in that it has a compressive strength between 1.30 and 1.50 MPa.

[0032] The present technology further includes a method for producing the PUR / PIR foam, the method comprising the steps of:

[0033] i) contacting at least one polyisocyanate compound with a polyol mixture comprising three (3) different polyols selected from polyether polyols and polyester polyols and one chain extender polyol in the presence of a catalyst, a blowing agent and optionally a flame retardant and additives;

[0034] ii) depositing the PUR / PIR foam composition onto a stack of glass fibers or a stack of glass mats, and

[0035] iii) allowing the formulation to solidify after expansion to form a foam block.

[0036] The foam thus obtained can be used as a thermal insulation material, in particular as a thermal insulation material for LNG tankers.

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

[0038] definition

[0039] In the context of the present technology, whether or not the term "about" is explicitly used, all amounts present in the context of the present specification refer to the actual value given, but also to the approximate value of the given value that can be reasonably inferred based on the technical personnel in the field, including the equivalent and approximate value of the given value caused by the experimental and / or measurement conditions. For example, in the context of a given value or range, the term "about" refers to a value or range within 20%, preferably within 15%, more preferably within 10%, more preferably within 10%, more preferably within 9%, more preferably within 8%, more preferably within 7%, more preferably within 6%, more preferably within 5% of the given value or range.

[0040] In the context of the present technology, "polyol" is understood to mean any organic compound containing at least two hydroxyl groups (-OH) in the molecular structure. The reactivity of a polyol is defined by various parameters, such as functionality, hydroxyl number and aromaticity.

[0041] Functionality refers to the average number of reactive hydroxyl groups present per molecule. During the foam production process, the hydroxyl groups react with isocyanate groups (-NCO) attached to the isocyanate compound.

[0042] The hydroxyl number or OH value (also denoted by HV) of a polyol refers to the number of active hydroxyl groups (-OH) available for reaction. The hydroxyl number is expressed as milligrams (mg) of potassium hydroxide (KOH) corresponding to the hydroxyl content in one gram (g) of polyol, expressed in the present application as "mg KOH / g polyol". The hydroxyl number is thus determined in accordance with ASTM standard D4274-16. The determination of the hydroxyl number makes it possible, in particular, to assess the crosslinking efficiency of a formulation.

[0043] Aromaticity is an intrinsic property of a compound due to the presence of a particularly stable cyclic planar structure. A compound is said to be aromatic if its structure complies with Hückel's rule.

[0044] "Polyether polyols" are understood to mean polyols containing one or more ether functional groups in the molecular structure. "Polyester polyols" are understood to mean polyols containing one or more ester functional groups in the molecular structure.

[0045] The term "chain extender polyol" refers to polyol molecules that, when these same molecules are covalently included in the synthesis of a final product, facilitate the formation of chemical bonds and enhance the physical properties of the resulting compound.

[0046] "Isocyanate compound" or "isocyanate" is understood to mean any compound containing at least one isocyanate functional group within the molecular structure. The term "polyisocyanate compound" or "polyisocyanate" refers to any organic compound having at least two isocyanate (-NCO) groups within the molecular structure.

[0047] PUR, PIR and PIUR foams are obtained by chemical reaction between polyols and polyisocyanates and have different properties depending on the nature of the compounds and the proportions in which they are formulated. They are defined in particular by the isocyanate / polyol (NCO / OH) ratio, also known as the index, which corresponds to the number of isocyanate groups divided by the number of hydroxyl groups of the polyol and any other component containing such groups.

[0048] Thus, it is possible to distinguish between polyurethane (PUR) foams having an NCO / OH ratio between 1:1 and 1.3:1, polyurethane / polyisocyanurate (PUR / PIR) foams having a ratio between 1.3:1 and 1.8:1 and polyisocyanurate (PIR) foams having a ratio between 1.8:1 and 2.8:1.

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

[0050] The "closed cells storing gas" contemplated by the present technology contain gas derived from the blowing agent, either by chemical reaction in the case of a chemical blowing agent, such as carbon dioxide (CO2) if the chemical blowing agent is water, or a physical blowing agent, such as molecular nitrogen (N2), molecular oxygen (O2), carbon dioxide (CO2), hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons or mixtures. The physical blowing agent is dispersed in the liquid copolymer mass in the form of a gas or liquid. During the foam formation process, nucleation and subsequent growth of bubbles will produce a closed cell structure storing gas.

[0051] The term "blowing agent" refers to a compound that causes the composition to expand during the foaming step by chemical and / or physical action.

[0052] In addition to the compounds that are essential to their formulation, PUR / PIR foams may also contain flame retardants. As the name suggests, flame retardants are compounds that have the property of reducing or preventing the burning or heating of the material containing them.

[0053] In the context of the present technology, the various ingredients used in the PUR / PIR foam composition are defined as percentages relative to the total weight of the polyol. The content of the various ingredients can also be expressed as weight parts (pw) relative to the total weight of the polyol in the composition.

[0054] Polyol mixture

[0055] The present technology relates to a polyol mixture for preparing polyurethane / polyisocyanurate (PUR / PIR) foam, characterized in that the polyol mixture comprises three (3) different polyols and a chain extender polyol, wherein the different polyols are selected from polyether polyols and polyester polyols.

[0056] The polyether polyols and polyester polyols used in compositions for formulating PUR / PIR foams are well known to those skilled in the art.

[0057] Polyether polyols

[0058] The 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, a hydroxyl number between about 250 mg KOH / g polyol and about 1000 mg KOH / g polyol.

[0059] In the context of the present technology, the polyether polyol has a molecular weight of less than or equal to about 1000 g / mol, preferably less than or equal to about 800 g / mol. In one embodiment, the polyether polyol has a molecular weight of greater than or equal to about 200 g / mol. In another embodiment, the polyether polyol used in the PUR / PIR foam composition has a molecular weight between about 200 g / mol and about 800 g / mol. The polyether polyol according to the technology advantageously has a molecular weight between about 200 g / mol and about 600 g / mol, preferably between about 300 g / mol and about 600 g / mol.

[0060] In another embodiment, the polyether polyol has a molecular weight between about 350 g / mol and about 600 g / mol, between about 400 g / mol and about 600 g / mol, between about 450 g / mol and about 600 g / mol, or between about 500 g / mol and about 600 g / mol. In another embodiment, the polyether polyol used in the PUR / PIR foam composition advantageously has 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 in the polyol mixture used to prepare the PUR / PIR foams have a hydroxyl value between about 50 mgKOH / g polyol and about 850 mgKOH / g polyol. In the context of the present technology, the mixture contains polyether polyols having a hydroxyl value of less than or equal to about 800 mgKOH / g polyol, preferably less than or equal to about 700 mgKOH / g polyol, or even less than or equal to about 600 mgKOH / g polyol. In one embodiment, the polyether polyol has a hydroxyl value between about 50 mgKOH / g polyol and about 600 mgKOH / g polyol, preferably between about 100 mgKOH / g polyol and about 600 mgKOH / g polyol, more preferably between about 200 mgKOH / g polyol and about 600 mgKOH / g polyol. In another embodiment, the polyether polyol has a hydroxyl number between about 100 mgKOH / g polyol and about 300 mgKOH / g polyol, between about 200 mgKOH / g polyol and about 300 mgKOH / g polyol, between about 200 mgKOH / g polyol and about 400 mgKOH / g polyol, or between about 300 mgKOH / g polyol and 400 mgKOH / g polyol. In another embodiment, the hydroxyl number of the polyether polyol used in the polyol mixture for preparing PUR / PIR foam is between about 400 mgKOH / g polyol and about 600 mgKOH / g polyol, or between about 300 mgKOH / g polyol and about 500 mgKOH / g polyol. The polyether polyol advantageously has a hydroxyl value between about 350 mgKOH / g and about 400 mgKOH / g polyol, or between about 350 mgKOH / g polyol and about 500 mgKOH / g polyol. More specifically, the polyether polyol has a hydroxyl value between about 350 mgKOH / g and about 390 mgKOH / g polyol, preferably between about 350 mgKOH / g and about 360 mgKOH / g polyol. In another embodiment, the hydroxyl value of the polyether polyol is between about 390 mgKOH / g and about 500 mgKOH / g polyol, more specifically, between about 390 mgKOH / g and about 470 mgKOH / g polyol.

[0062] The polyether polyol can be defined by its functionality and viscosity. Thus, the polyether polyol used in the polyol mixture for preparing PUR / PIR foam has a functionality between 3 and 8, preferably between 3 and 6. The viscosity of the polyether polyol is less than 5000 mPa.s at 25°C, preferably less than or equal to 4000 mPa.s at 25°C. In one embodiment, the viscosity of the polyether polyol is between 2500 and 3000 mPa.s at 25°C. In another embodiment, the viscosity at 25°C is less than 1500 mPa.s. In another embodiment, the viscosity of the polyether polyol is about 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 are 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 polyol used in the polyol mixture for preparing PUR / PIR foams is a polyol based on sucrose and / or sorbitol.

[0065] The polyether polyols used in the polyol mixtures for preparing the PUR / PIR foams are advantageously polyols based on glycerol and sorbitol and / or polyols based on glycerol and sucrose.

[0066] Such polyether polyols are commercially available. In particular, they include those sold by Huntsman Corporation R404, sold by Bayer 9260, 4030 and 4034, sold by Arco Chemical Company R-572, sold by Olin Chemical Company 74-53, sold by Dow Chemical Company 202, 280, 360, 370, 490, 520, 615 and 800, and ICI Polyurethanes sold R180 and R140.

[0067] The polyether polyols used in the polyol mixture for formulating the foam are preferably compounds sold by Huntsman Corporation and the Dow Chemical Company, more particularly the compounds R404 and 360.

[0068] The polyether polyols used in the polyol mixture can be the same or different, and therefore have the same or different intrinsic properties. In one embodiment, the polyether polyols are the same. In another embodiment, advantageously, the polyether polyols are different.

[0069] Polyester polyols

[0070] The polyol mixture according to the present technology comprises, in addition to the polyether polyol, also a polyether polyol.

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

[0072] Meanwhile, the polyester polyol used in the polyol mixture for preparing PUR / PIR foam has a hydroxyl value between about 100 mgKOH / g polyol and about 400 mgKOH / g polyol, preferably between about 150 mgKOH / g polyol and about 400 mgKOH / g polyol, more preferably between about 150 mgKOH / g polyol and about 350 mgKOH / g polyol. In another embodiment, the polyester polyol according to the present technology has a hydroxyl value between about 200 mgKOH / g and about 350 mgKOH / g polyol, preferably between about 200 mgKOH / g and about 300 mgKOH / g polyol, more preferably between about 220 mgKOH / g polyol and about 300 mgKOH / g polyol. More specifically, the polyether polyol present in the polyol mixture has a hydroxyl number between about 220 mgKOH / g polyol and about 270 mgKOH / g polyol, between about 220 mgKOH / g polyol and about 260 mgKOH / g polyol, between about 220 mgKOH / g polyol and about 250 mgKOH / g polyol, or between about 230 mgKOH / g polyol and 250 mgKOH / g polyol.

[0073] As regards the functionality of the polyester polyol used in the composition, it is between 1.5 and 5, preferably between 1.5 and 3. In one embodiment, the functionality of the polyester polyol is between 1.5 and 2.5. The polyester polyol advantageously has a functionality of 2.

[0074] Like the polyether polyols, the polyester polyols have a viscosity of less than 5000 mPa.s at 25° C. According to one embodiment, the viscosity is greater than or equal to 1000 mPa.s, or even greater than or equal to 2000 mPa.s. The viscosity of the polyether polyols used in the polyol mixture for preparing PUR / PIR foams is advantageously between 2500 and 4500 mPa.s at 25° C., preferably between 2500 and 4000 mPa.s, more preferably between 3000 and 4000 mPa.s at 25° C.

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

[0076] From a structural point of view, the polyether polyol used in the polyol mixture for preparing PUR / PIR foam according to the present technology is an aromatic polyether polyol obtained by esterification of phthalic acid or phthalic anhydride. In one embodiment, the polyester polyol is an aromatic polyester polyol, preferably a phthalic acid derivative.

[0077] Examples of commercially available polyester polyols are sold by Stepan Corporation. PS-2352, PS-1752, PS-3152 and PS-3024.

[0078] In one embodiment, the polyester polyol used in the polyol mixture is Compounds, more particularly PS-2352.

[0079] Mixture of 3 different polyols

[0080] In the context of the present technology, the polyol mixture used to prepare PUR / PIR foams comprises a mixture of three (3) different polyols, the polyols being selected from the polyether polyols and polyester polyols defined above. In one embodiment, the mixture of three (3) different polyols comprises three (3) polyether polyols. In another embodiment, the mixture of three (3) different polyols comprises two (2) polyether polyols and one (1) polyester polyol. In another embodiment, the mixture of three (3) different polyols comprises one (1) polyether polyol and two (2) polyester polyols. In another embodiment, the mixture of three (3) different polyols comprises three (3) polyester polyols. The mixture of three (3) different polyols according to the present invention advantageously comprises two (2) polyether polyols and one (1) polyester polyol.

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

[0082] Chain Extender Polyol

[0083] The polyol mixture used to formulate PUR / PIR foams additionally comprises a chain extender polyol. The polyol mixture thus comprises: a mixture of three (3) different polyols selected from polyether polyols and polyester polyols, and a chain extender polyol. Chain extender 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 a carbon number of 2 to 14.

[0084] In the context of the present technology, the chain extender polyol has a molecular weight between about 50 g / mol and about 300 g / mol, preferably between about 50 g / mol and about 250 g / mol, more preferably between about 50 g / mol and about 200 g / mol. The chain extender polyol advantageously has a molecular weight between about 100 g / mol and about 150 g / mol. In a preferred embodiment, the chain extender polyol has a molecular weight of about 134 g / mol.

[0085] The chain extender polyol used in the polyol mixture for preparing PUR / PIR foam has a hydroxyl value between about 100 mgKOH / g polyol and about 1000 mgKOH / g polyol. In one embodiment, the chain extender polyol has a hydroxyl value greater than or equal to about 200 mgKOH / g polyol, preferably greater than or equal to about 300 mgKOH / g polyol, more preferably greater than or equal to about 500 mgKOH / g polyol. In another embodiment, the chain extender polyol has a hydroxyl value between about 500 mgKOH / g polyol and about 1000 mgKOH / g polyol, preferably between about 600 mgKOH / g polyol and about 1000 mgKOH / g polyol, more preferably between about 700 mgKOH / g polyol and about 1000 mgKOH / g polyol. In another embodiment, the chain extender polyol used in the polyol mixture according to the present technology has a hydroxyl value between about 800 mgKOH / g polyol and about 950 mgKOH / g polyol, preferably between about 800 mgKOH / g polyol and about 900 mgKOH / g polyol. The chain extender polyol advantageously has a hydroxyl value between about 800 mgKOH / g polyol and about 850 mgKOH / g polyol, preferably between about 820 mgKOH / g polyol and about 850 mgKOH / g polyol, more specifically, between about 830 mgKOH / g polyol and about 850 mgKOH / g polyol. In a preferred embodiment, the chain extender polyol has a hydroxyl value of about 837 mgKOH / g polyol.

[0086] An additional characteristic of the chain extender polyol is the functionality. In the present technology, the chain extender polyol has a functionality of about 2. The chain extender polyol advantageously has a functionality of 2.

[0087] The viscosity of the chain extender polyol is between 50 and 500 mPa.s, preferably between 100 and 300 mPa.s, more preferably between 150 and 250 mPa.s at 25° C. More specifically, the viscosity of the chain extender polyol is between 175 and 225 mPa.s, preferably between 190 and 210 mPa.s at 25° C. The polyol mixture for preparing PUR / PIR foams advantageously comprises a chain extender polyol having a viscosity of 200 mPa.s at 25° C.

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

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

[0090] Mixture of 4 polyols

[0091] A mixture of three (3) different polyols selected from polyether polyols and polyester polyols and a chain extender polyol, thus defining a polyol mixture for preparing PUR / PIR foams according to the present technology.

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

[0093] about 20 pw to about 100 pw of a polyether polyol, preferably about 10 pw to about 70 pw of a first polyether polyol and about 10 pw to 40 pw of a second polyether polyol;

[0094] From about 5 pw to about 50 pw of a polyester polyol; and

[0095] From about 10 pw to about 30 pw of a chain extender polyol.

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

[0097] about 28 to about 100 pw of a polyether polyol, preferably about 18 to 67 pw of a first polyether polyol and about 10 to 25 pw of a second polyol;

[0098] From about 5 pw to about 40 pw of a polyester polyol; and

[0099] From about 15 pw to about 30 pw of a chain extender polyol.

[0100] Preferably, the polyol mixture comprises:

[0101] about 65 to about 80 pw of a polyether polyol, preferably about 44 to 55 pw of the first polyether polyol and about 15 to 25 pw of the second polyol;

[0102] From about 20 pw to about 35 pw of a polyester polyol; and

[0103] From about 15 pw to about 25 pw of a chain extender polyol.

[0104] More preferably, the polyol mixture comprises:

[0105] about 65 to about 80 pw of a polyether polyol, preferably about 48 to 55 pw of the first polyether polyol and about 17 to 23 pw of the second polyol;

[0106] From about 25 pw to about 32 pw of a polyester polyol; and

[0107] From about 18 pw to about 25 pw of a chain extender polyol.

[0108] The polyol mixture comprises three (3) different polyols and a chain extender polyol, the different polyols being selected from polyether polyols and polyester polyols, and advantageously comprising, in parts by weight relative to the total weight of the polyols:

[0109] About 70 pw of polyether polyol;

[0110] about 30 pw of polyester polyol; and

[0111] About 20 pw of chain extender polyol.

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

[0113] about 50 pw of a first polyether polyol;

[0114] about 20 pw of a second polyether polyol;

[0115] about 30 pw of polyester polyol; and

[0116] About 20 pw of chain extender polyol.

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

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

[0119] from about 10% to about 50% polyester polyol; and

[0120] From about 5% to about 35% of a chain extender polyol.

[0121] In another embodiment, the polyol mixture for preparing PUR / PIR foam comprises, in terms of mass percentage relative to the total weight of the polyols:

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

[0123] from about 15% to about 35% polyester polyol; and

[0124] From about 10% to about 25% of a chain extender polyol.

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

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

[0127] from about 20% to about 30% polyester polyol; and

[0128] From about 15% to about 25% of a chain extender polyol.

[0129] The polyol mixture advantageously comprises, in percentage by mass relative to the total weight of the polyols:

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

[0131] about 24% polyester polyol; and

[0132] About 18% chain extender polyol.

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

[0134] PUR / PIR foam compositions

[0135] A polyol mixture comprising three (3) different polyols selected from polyester polyols and polyether polyols and a chain extender polyol can be used to prepare PUR / PIR foams.

[0136] PUR / PIR foam is a cellular structure consisting of small closed cells enclosing a gas. The formation of PUR / PIR type 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. This condensation reaction can be catalyzed by compounds having alkaline and / or nucleophilic properties such as tertiary amines, organometallic complexes or alkali metal complexes.

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

[0138] Polyisocyanate compounds

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

[0140] Polyisocyanate compounds suitable for use in PUR / PIR foam compositions are well known to those skilled in the art. Polyisocyanate compounds include aromatic, aliphatic, cycloaliphatic and araliphatic polyisocyanates and mixtures thereof.

[0141] In the context of the present technology, a polyisocyanate compound is a diisocyanate compound, ie a compound comprising two isocyanate groups, which may be aliphatic or aromatic.

[0142] The polyisocyanate compound has a viscosity between 100 and 3000 mPa.s at 25° C. The polyisocyanate used in the PUR / PIR foam composition has a viscosity less than or equal to 2000 mPa.s, or even less than 1000 mPa.s. In one embodiment, the polyisocyanate has 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, advantageously between 2.7 and 3.1.

[0144] The diisocyanate compounds suitable for the present invention include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane 4,4'-diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate (CHDI), bis(isocyanatomethyl)cyclohexane (H6XDI, DDI), meta-xylene diisocyanate (m-XDI), tetramethylxylene diisocyanate (TMXDI), toluene diisocyanate (TDI) compounds, such as isomeric toluene 2,4- and 2,6-isocyanates (2,4-TDI and 2,6-TDI); methylene diphenyl diisocyanate (MDI) compounds, such as isomers of methylene diphenyl 4,4'-, 2,4'- and 2,2'-diisocyanates (2,4'-MDI, 2,4'-MDI and 2,2'-MDI), and dibenzyl diisocyanate compounds, such as isomers of dibenzyl 4,4'- and 2,4'-diisocyanates (4,4'-DBDI and 2,4'-DBDI).

[0145] In one embodiment of the present technology, the polyisocyanate compound is an aromatic diisocyanate compound, preferably selected from toluene diisocyanate (TDI) compounds, methylene diphenyl diisocyanate (MDI) compounds and dibenzyl diisocyanate (DBDI) compounds. The diisocyanate compound is advantageously selected from methylene diphenyl diisocyanate (MDI) compounds.

[0146] The diisocyanate compound can alternatively be obtained by commercial purchase. Examples of such compounds are Dow Chemical Company's like CL100 or CE101 or like 27, or Huntsman's S5005 and S2085, and BASF M20 and M50.

[0147] In the context of the present technology, it is understood that the diisocyanate compound may be a mixture of a plurality of diisocyanate compounds as defined above.

[0148] Except polyol mixture, the existence of polyisocyanate compound is most important to the formation of foam.Therefore, the consumption of polyisocyanate is that every 100pw polyol is at least about 70pw.In one embodiment, the consumption of polyisocyanate is that every 100pw polyol is between about 70pw and about 140pw, preferably between about 80pw and about 130pw, more preferably between about 83pw and about 128pw.The consumption of polyisocyanate is advantageously that every 100pw polyol is between about 85pw and about 125pw, preferably between about 87pw and about 123pw, more preferably between about 90pw and about 120pw.

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

[0150] In addition, the amount 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, 1.8:1. In the context of the present invention, the foam obtained is a PUR / PIR type foam with an isocyanate / polyol ratio between 1 and 1.25.

[0151] catalyst

[0152] "Catalyst" is understood to mean any compound which accelerates the polymerization or condensation reaction between polyols and polyisocyanates.

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

[0154] The catalyst may be a gelling, expanding, curing or trimerization catalyst customary in the preparation of PIR foams. Reference may therefore be made to the compounds described in "Kunststoffhandbuch" (Plastics Handbook), Volume 7 "Polyurethanes", Carl Hanser Verlag, 3rd edition, 1993, Chapter 3.4.1.

[0155] In the context of the present technology, the catalyst is selected from organometallic catalysts, in particular from tin or tin-based catalysts, bismuth-based catalysts and alkali metal carboxylates.

[0156] In one embodiment, the catalyst is selected from tin (II) carboxylates such as tin acetate, tin octoate, tin ethylhexanoate, tin laurate, and tin (IV) carboxylates such as dibutyltin diacetate, dibutyltin dilaurate (DBTDL), dibutyltin maleate, and dioctyltin diacetate.

[0157] In another embodiment, the catalyst used in the PUR / PIR foam composition is a bismuth-based catalyst, especially a bismuth carboxylate, a bismuth alkanolamine, or a bismuth thiol. Examples of these compounds are bismuth neodecanoate, bismuth 2-ethylhexanoate, and bismuth octoate.

[0158] In another embodiment, the catalyst used is an alkali metal carboxylate, preferably a potassium carboxylate, such as potassium acetate, potassium formate or potassium octoate. Advantageously, the catalyst is potassium octoate.

[0159] In another embodiment, the catalyst corresponds to a catalyst mixture, 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 octoate.

[0160] Therefore, the catalyst used in the PUR / PIR foam composition is selected from tin catalysts, potassium carboxylates or mixtures thereof.

[0161] Commercially available catalysts such as those sold by Evonik Industries can also be used in PUR / PIR foam compositions. Type catalysts, more particularly 5. 9 and 203, or sold by Evonik Industries Type catalysts, such as T12N.

[0162] Foaming agent

[0163] The PUR / PIR foam composition further comprises a blowing agent. The blowing agent makes it possible to obtain a foamed honeycomb structure and can be a physical blowing agent and / or a chemical blowing agent in nature. The blowing agent is advantageously a combination of a physical blowing agent and a chemical blowing agent.

[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-di-chloro-1,1,1-trifluoroethane) and HCFC-141b (1,1-dichloro-1-fluoroethane).

[0166] Therefore, in one embodiment of the present invention, the blowing agent is selected from 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), HFC-152a (1,1-difluoroethane) or hydrofluoroolefins (HFOs), such as HFO-1234yf (2,3,3,3-tetrafluoropropene), HFO-1234ze (1,3,3,3-tetrafluoropropene) or HFO-1233zd (1-chloro-3,3,3-trifluoropropene).

[0167] In another embodiment, the blowing agent is a chemical agent, in particular carbon dioxide (CO2) and / or water. Specifically, the presence of water as a blowing agent results in the generation of carbon dioxide, thereby expanding the foam. The preferred chemical blowing agent is water.

[0168] Physical blowing agents and chemical blowing agents can be used alone or simultaneously. According to a variant of the present invention, the blowing agent comprises a physical blowing agent and a chemical blowing agent. Therefore, according to one embodiment, the blowing agent is a mixture comprising hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs) and / or carbon dioxide (CO2), wherein the hydrofluorocarbons and hydrofluoroolefins are selected from the compounds mentioned above. In another embodiment, the blowing agent is a mixture comprising HFC-365mfc and / or HFC-245fa in combination with water.

[0169] The formulations of the PUR / PIR foams according to the invention may comprise one or more blowing agents.

[0170] In one embodiment, the composition comprises a blowing agent selected from water, CO2, a fluorinated blowing agent as defined above, or a mixture thereof.

[0171] The amount of physical blowing agent is calculated based on the density of the PUR / PIR foam. The amount of physical blowing agent is preferably between 0 wt % and about 10 wt % relative to the total weight of the polyol. In one embodiment, the amount of blowing agent is between about 2 wt % and about 10 wt %, preferably between about 5 wt % and about 10 wt %, relative to the total weight of the polyol. In the PUR / PIR foam composition, the amount of blowing agent is advantageously about 7 wt % relative to the total weight of the polyol.

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

[0173] Flame retardants

[0174] Flame retardants are usually included in the composition of PUR / PIR foams to limit the flammability and increase the fire resistance of the foams. Flame retardants are well known to the person skilled in the art and are described in Kunststoffhandbuch (Plastics Handbook), Volume 7, Polyurethanes, Chapter 6.1.

[0175] Compounds used as flame retardants include, inter alia: brominated compounds B251, dibromoneopentyl alcohol, tribromoneopentyl alcohol, known as PHT4-diol TM tetrabromophthalic acid 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 containing phosphorus, expandable graphite, hydrated aluminum oxide, antimony trioxide, ammonium polyphosphate, calcium sulfate or cyanuric acid derivatives, such as melamine, or mixtures of at least two flame retardants, such as ammonium phosphate and melamine.

[0177] Examples of other halogen-free liquid flame retardants include diethyl ethyl phosphate (DEEP), triethyl phosphate (TEP), dimethyl propyl phosphate (DMPP), or diphenyl toluene phosphate (DPC).

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

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

[0180] additive

[0181] The formulations may also comprise further additives customary in the preparation of PUR / PIR foams, such as surfactants, stabilizers, emulsifiers, plasticizers, dyes or crosslinkers.

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

[0183] In one embodiment, the formulation includes at least one surfactant. Surfactants, also known as surface-active agents or emulsifiers, are compounds that change the surface tension between two surfaces. They therefore have the effect of dissolving at least two immiscible phases. In the context of the present technology, the PUR / PIR foam composition may include one or more surfactants. In essence, these compounds may be silicone or non-silicone, or a mixture thereof. Examples of silicone surfactants suitable for formulating PUR / PIR foams are sold by Evonik. B-8427, B-2454, B-8404, B-8407, B-8409, B-8462, B-8465, B-8315, B-1048 and B-84507 sold by Momentive, L-5130, L-5180, L-5340, L-5440, L-6100, L-6900, L-6980 and L-6980 sold by Dow Corning, DC-5374, DC-193, DC-197, DC-5582 and DC-5598 sold by Dow Corning. Examples of non-silicone surfactants are oxyethylated alkylphenol compounds, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, peanut oil and fatty alcohols.

[0184] Characteristics of PUR / PIR foam

[0185] The PUR / PIR foam composition comprising a polyol mixture, a catalyst, one or more blowing agents, and optionally one or more additives is particularly suitable for ensuring, in liquid form, a uniform distribution of the foam. "Uniform" distribution is understood to mean that the foam is uniformly and evenly distributed over the entire support or surface on which the liquid composition is deposited before expansion. Once the foam is obtained, it will have uniform and consistent thermal and mechanical properties at all points of the material.

[0186] The foam thus has physicochemical properties and specific mechanical properties, especially due to its composition.

[0187] Examples of physicochemical properties are thermal conductivity, density, and compressive strength.

[0188] In liquid form, or more specifically, in the form of an emulsion, the foam has an interesting stability, with a cream time of about sixty (60) seconds. Cream time can be defined as the time from the start of the mixing stage of all ingredients to the moment when the first bubbles appear, a color change of the composition is observed, or the mixture expands into foam. Cream time is defined according to ASTM standard D7487.

[0189] Once the foam is formed, it has a mass of less than 150 kg / m 3 , even less than 140kg / m 3 In one embodiment, the density of the obtained foam is between 90 and 140 kg / m 3 Between, preferably between 100 and 140 kg / m 3 Between 110 and 130 kg / m 3 In another embodiment, the PUR / PIR foam according to the present technology has a weight between 115 and 125 kg / m 3 Between 116 and 122 kg / m 3 Between 118 and 122 kg / m 3 In a preferred embodiment, the PUR / PIR foam has a density of about 120 kg / m 3 density.

[0190] At the same time, the PUR / PIR foam has a thermal conductivity of less than 30 mW / mK, or even less than 27 mW / mK. Thermal conductivity provides information about the ability of the foam to diffuse heat. Therefore, the lower the thermal conductivity, the stronger the thermal insulation of 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 specifically, 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 about 25 mW / mK.

[0191] As regards mechanical properties, the foams obtained can be characterized by compressive strength, elastic modulus under compression, tensile or shear strength, flexural strength, etc.

[0192] The compressive strength defines the ability of the foam to withstand an applied compressive load, ie an external load applied to the foam in order to obtain a deformation and / or size of the foam.

[0193] In the context of the present 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, more preferably between 1.30 and 1.50 MPa. According to the ISO844 standard, the compressive strength of the PUR / PIR foam is advantageously between 1.40 and 1.50 MPa.

[0194] Method for producing PUR / PIR foam blocks

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

[0196] PUR / PIR foams are the result of a physicochemical process in which a 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 expand.

[0197] The method for producing a PUR / PIR foam block according to the present technology thus comprises the following steps:

[0198] i) contacting at least one polyisocyanate compound with a polyol mixture comprising three (3) different polyols selected from polyether polyols and polyester polyols and one chain extending polyol in the presence of a catalyst, a blowing agent and optionally additives and flame retardants;

[0199] ii) depositing the foam composition obtained in step i) on a support; and

[0200] iii) allowing the composition to solidify after expansion to form a foam block.

[0201] Thus, in a first step, at least one polyisocyanate compound is contacted with a polyol mixture consisting of three different polyols and one chain extender polyol in the presence of a catalyst, a blowing agent and optional additives. The mixing is preferably carried out at ambient temperature using a "low pressure" or "high pressure" machine. "Low pressure" and "high pressure" machines are well known to those skilled in the art, who are able to determine the machine to be used, in particular according to the composition and properties of the foam.

[0202] The obtained mixture corresponding to the PUR / PIR foam composition according to the present technology is then quickly poured onto the support so as to distribute the composition evenly over the entire support.

[0203] The PUR / PIR foam composition, which is initially in liquid form, becomes foam by chemical reaction. This foam expansion step can be free or forced.

[0204] In one embodiment, the expansion is considered free, i.e. without the application of pressure resulting from a volume enclosed by a cross-section. In another embodiment, the expansion of the foam is physically limited by the walls of a double belt laminator, preferably a double belt laminator forming a tunnel of rectangular cross-section, wherein the distance between the laterally placed walls is equal to L and the distance between the horizontally placed walls is equal to E, thereby enclosing the expanding foam to obtain a foam block of defined dimensions.

[0205] The foam is then allowed to solidify.The final curing or solidification step can be carried out at elevated temperature or at ambient temperature.

[0206] It is understood that when a foam block is prepared by free expansion, the foam block can be cut to obtain a foam block of a size and shape that meets the desired properties. This cutting step can be performed before or after the foam block solidifies.

[0207] In a preferred embodiment, the pouring step is carried out on a support of a reinforcing material, such as a stack of glass fibers or a stack of glass mats, to obtain a fiber foam block. Then, the method comprises the following steps:

[0208] i) contacting at least one polyisocyanate compound with a polyol mixture comprising three (3) different polyols selected from polyether polyols and polyester polyols and a chain extender polyol in the presence of a catalyst, a blowing agent and optionally additives and flame retardants;

[0209] ii) depositing the foam composition obtained in step i) on a stack of glass fibers or a stack of glass mats, and

[0210] iii) allowing the composition to solidify after expansion to form a foam block.

[0211] In this case, the PUR / PIR foam composition mixture is poured onto the reinforcing material in such a way that the formulation is impregnated over the entire thickness of the glass fiber stack or glass mat stack. The content of glass fibers or glass fiber mats can be determined in particular according to the ISO 1172 standard.

[0212] A particular advantage of the foam composition is that it can penetrate quickly and evenly into the reinforcement material.

[0213] The glass fiber mats preferably used are made of continuous glass fiber mats (continuous strand mats), especially those manufactured by Owens Corning under the trade name or Fiberglass mat sold under the trade name GLASS.

[0214] These glass fibers are connected together by a binder, which is preferably present in an amount of about 0.6 mass % to about 3 mass %, preferably about 2.5 mass %, relative to the total mass of the glass fiber mat. The binder is used to size the glass fibers and is preferably an epoxy resin.

[0215] The glass fibers constituting the glass fiber mats preferably used have a linear density of 20 to 40 tex, ie 20 to 40 g per kilometer of fiber.

[0216] The mass per unit area of ​​the glass fiber mat is preferably between 300 and 900 g / m 2 Between, more advantageously between 300 and 600 g / m 2 More preferably, between 450g / m 2 Preferably, the glass fibers constitute 6 to 12% by mass of the total mass of the reinforced PUR / PIR foam. Advantageously, the glass fibers constitute about 10% by mass of the total mass of the PUR / PIR foam.

[0217] To obtain acceptable mechanical properties, the number of glass mats varies from 4 to 12, depending on the amount of binder used and the mass of the glass mat per unit area.

[0218] According to a second embodiment, the glass fibers preferably used are advantageously made of rovings, ie flat strips of different widths consisting of glass fibers which are not twisted but remain parallel to each other. The glass fibers are preferably deposited according to the webforming process of Plastech T.T. Ltd.

[0219] Glass fibers deposited by this process preferably have a linear density of 30 to 300 tex.

[0220] Application of PUR / PIR foam

[0221] PUR / PIR foam has a wide range of uses due to its insulating and adhesive properties. The PUR / PIR foam according to this technology is stable, has low thermal conductivity, and excellent mechanical properties such as shear strength, compressive strength and Young's modulus. At the same time, the foam shows a uniform distribution over the entire reinforcement. According to the present invention, the foam is particularly suitable for thermal insulation, more particularly for the insulation of transport tanks for liquefied gases such as liquefied petroleum gas (LPG) or liquefied natural gas (LNG), or for the insulation of transport tanks for cold liquid products such as ammonia or hydrogen used in liquefied natural gas LNG carriers. The present invention can also be used for the insulation of pipelines or storage tanks of ships, or for the insulation of pipelines and storage tanks on land or in ports.

[0222] In another embodiment, the PUR / PIR foam according to the present invention is used in the formation of insulation panels.

[0223] A composition comprising a polyol mixture, at least one polyisocyanate compound, a catalyst and optional additives is deposited on a surface to form a foam block. The deposition rate is calculated based on the height and desired density of the desired foam block. Those skilled in the art will know how to determine these different parameters.

[0224] After the foam has expanded and solidified, the sides, top and / or bottom of the foam block are removed. By this trimming step, it is possible to obtain a foam block of a specific size.

[0225] These PUR / PIR foam blocks can also be cut transversely to one third of their thickness to form two layers, a primary thermal insulation layer and a secondary thermal insulation layer. This single cutting step of cutting a single foam block thus makes it possible to obtain the primary thermal insulation layer and the secondary thermal insulation layer simultaneously, achieving a saving of material due to low losses and a saving of time since only one step is necessary for the production of two thermal insulation layers.

[0226] Example

[0227] Example 1: Example of composition No. 1 of polyurethane / polyisocyanurate foam according to one aspect of the present technology

[0228]

[0229]

[0230] Example 2: Example of a polyurethane / polyisocyanurate foam composition according to one aspect of the present technology

[0231]

[0232] References

[0233] US 2010 / 0116829

[0234] US 8940803

[0235] WO 2020 / 104749

Claims

1. A polyol mixture for preparing polyurethane / polyisocyanurate (PUR / PIR) foam, characterized in that The polyol mixture comprises three (3) different polyols and a chain extender polyol, the different polyols are selected from polyether polyols and polyester polyols, and the polyol mixture has a viscosity of less than 1000 mPa.s at 25°C.

2. The polyol mixture according to claim 1, characterized in that The polyether polyol is a polyol based on glycerol and sorbitol and / or a polyol based on glycerol and sucrose.

3. The polyol mixture according to claim 1 or 2, characterized in that The polyester polyol is an aromatic polyester polyol, preferably a phthalic acid derivative.

4. The polyol mixture according to any one of claims 1 to 3, characterized in that The chain extender polyol is a diol derivative, preferably dipropylene glycol.

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

6. The polyol mixture according to any one of claims 1 to 5, characterized in that The polyol mixture comprises: 28 pw to 100 pw of a polyether polyol, and 18 pw to 67 pw of a first polyether polyol, and 10 pw to 25 pw of a second polyether polyol; 5 pw to 40 pw of polyester polyol; as well as 15 pw to 30 pw of chain extender polyol.

7. A PUR / PIR foam composition, characterized in that: The composition comprises: The polyol mixture according to any one of claims 1 to 6; at least one polyisocyanate compound; and catalyst.

8. The composition according to claim 7, characterized in that The composition comprises between 90 and 120 pw of polyisocyanate per 100 pw of polyol.

9. The composition according to claim 7 or 8, characterized in that The polyisocyanate is selected from aromatic diisocyanates; preferably, the isocyanate compound is methylene diphenyl diisocyanate (MDI).

10. The composition according to any one of claims 7 to 9, characterized in that The catalyst is selected from tin catalyst and potassium carboxylate, or a mixture thereof.

11. The composition according to any one of claims 7 to 10, characterized in that The composition further comprises a blowing agent selected from the group consisting of water, CO2 and a fluorinated blowing agent, or a mixture thereof.

12. The composition according to any one of claims 7 to 11, characterized in that The composition further comprises one or more additives.

13. A polyurethane / polyisocyanurate foam obtained from the composition of any one of claims 7 to 12.

14. The polyurethane / polyisocyanurate foam according to claim 13, characterized in that The foam has a strength of 110 kg / m 3 and 130kg / m 3 The density between.

15. The polyurethane / polyisocyanurate foam according to claim 13 or 14, characterized in that The foam has a thermal conductivity between 24 mW / mK and 26 mW / mK.

16. The polyurethane / polyisocyanurate foam according to any one of claims 13 to 15, characterized in that The foam has a compressive strength between 1.30 MPa and 1.50 MPa.

17. A method for producing the polyurethane / polyisocyanurate foam according to any one of claims 13 to 16, the method comprising the following steps: i) contacting at least one polyisocyanate compound with the polyol mixture comprising three (3) different polyols and one chain extender polyol as claimed in claims 1 to 6 in the presence of a catalyst, a blowing agent and optionally a flame retardant and additives; and ii) depositing the foam composition obtained in step i) on a stack of glass fibers or a stack of glass mats; as well as iii) allowing the formulation to solidify after expansion to form a foam block.

18. Use of the polyurethane / polyisocyanurate foam according to claims 13 to 16 or obtained by the process according to claim 20 for thermal insulation.

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