FR3135268A1 - FORMULATION OF A POLYURETHANE/POLYISOCYANURATE FOAM - Google Patents

Abstract

The present technology relates to a mixture of polyols comprising three (3) different polyols and one chain extender polyols. This mixture is used for the preparation of a polyurethane/polyisocyanurate (PUR/PIR) foam when the mixture is reacted with at least one polyisocyanate compound in the presence of catalysts, blowing agents and optionally other additives. . The present technology therefore also relates to a PUR/PIR foam composition, the foam obtained and its process for obtaining it. PUR/PIR foam has interesting characteristics and physical properties, particularly in terms of density, mechanical resistance and thermal conductivity.

Description

FORMULATION OF A POLYURETHANE/POLYISOCYANURATE FOAM FIELD OF THE INVENTION

The present technology relates to a mixture of polyols for the preparation of polyurethane/polyisocyanurate (PUR/PIR) foam. The blend includes three (3) different polyols and one chain extender polyol. This mixture produces a PUR/PIR foam that is 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 as well as its process for obtaining it.

BACKGROUND OF THE INVENTION

Polyurethanes or polymers composed of one or more urethane molecules are well known to those skilled in the art and are used today in many fields as insulators, adhesives, or even as compounds for the automobile industry. , textile or furniture.

Polyurethanes are more particularly 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 make it possible to obtain polyurethane foams with different characteristics and properties specific to each composition.

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 having better fire-fighting properties and higher compressive strength than PUR foams.

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.

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

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

The inventors have thus discovered a composition for the formulation of a polyurethane foam responding to at least some of the shortcomings observed in the technical field until now.

BRIEF DESCRIPTION OF THE INVENTION

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

The present technology relates to a polyol blend, characterized in that the polyether polyols are polyols based on glycerol and sorbitol and/or polyols based on glycerol and sucrose.

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

The present technology relates to a mixture of polyols, characterized in that the chain extender polyol is a glycol type derivative, preferably dipropylene glycol.

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

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

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

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

- from 15 pp to 30 pp of a chain extender polyol.

The present technology therefore also concerns the composition of the foam, which may also include expanding agents and additives.

The present technology therefore also concerns the composition of a PUR/PIR foam, characterized in that the composition comprises:

- the mixture of polyols comprising three (3) different polyols and a chain extender polyol, as defined in the present technology,

- at least one polyisocyanate compound, and

- a catalyst.

The present technology therefore also concerns the composition of a PUR/PIR foam, characterized in that the composition comprises between 90 pp and 120 pp of polysiocyanate per 100 pp of polyols.

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).

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

The present technology therefore also relates to the composition of a PUR/PIR foam, characterized in that the composition further comprises a blowing agent chosen from water, CO ₂ and fluorinated blowing agents, or a mixture of these.

The present technology therefore also concerns the composition of a PUR/PIR foam, characterized in that it also comprises one or more additives.

The present technology also relates to the PUR/PIR foam obtained which has the following characteristics: a density of between 110 kg/m ³ and 130 kg/m ³ , a thermal conductivity of 24 mW/mK and 26 mW/ mK, and/or a compressive stress of between 1.30 MPa and 1.50 MPa.

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

The present technology also relates to PUR/PIR foam, characterized in that said foam has a density of between 110 and 130 kg/m ³ .

The present technology also relates to PUR/PIR foam, characterized in that said foam has thermal conductivity of between 24 and 26 mW/m.K.

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

1. mettre en contact au moins un composé polyisocyanate et le mélange de polyols comprenant trois (3) polyols différents et un polyol allongeur de chaine, lesdits polyols étant choisis parmi les polyols polyéthers et les polyols polyesters, en présence de catalyseur(s), d’agent(s) d’expansion et optionnellement de retardateur(s) de flamme et d’additif(s) ;
2. déposer la composition de la mousse PUR/PIR sur un empilement de fibres de verre ou de mat de verre, et
3. laisser solidifier ladite formulation après expansion de façon à former un bloc de mousse.

The present technology further comprises a process for manufacturing said PUR/PIR foam, said process comprising the steps of:

1. bringing into contact at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and a chain extender polyol, said polyols being chosen from polyether polyols and polyester polyols, in the presence of catalyst(s), blowing agent(s) and optionally flame retardant(s) and additive(s);
2. place the PUR/PIR foam composition on a stack of glass fibers or glass mat, and
3. allow said formulation to solidify after expansion so as to form a block of foam.

The foam thus obtained can be used as thermal insulation, and more particularly as insulation for LNG tankers.

The present technology also concerns the use of polyurethane/polyisocyanurate foam defined above, or obtained according to the process defined above for thermal insulation.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

In the context of the present technology, the term "approximately" is used explicitly or not, each quantity presented in the context of the present description refers to the real value given but also to the approximation of this given value which would be reasonably deduced on the basis of those skilled in the art, 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 within 20%, preferably within 15%, more preferably within of 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 value or range given.

In the context of the present technology, the term “polyols” means any organic compound bearing at least two hydroxyl groups (-OH) in their molecular structure. The reactivity of polyols is defined by different parameters such as functionality, hydroxyl number, and aromaticity.

Functionality refers to the average number of reactive hydroxyl groups present per molecule. During foam production, hydroxyl groups react with isocyanate groups (-NCO) which are bonded to isocyanate compounds.

The hydroxyl number, or OH number also noted IOH, of polyols refers to the number of reactive hydroxyl (-OH) groups available for the reaction. The hydroxyl number is expressed in milligram (mg) of potassium hydroxide (KOH) equivalent to the hydroxyl content of one gram (g) of polyols, and denoted “mg KOH/g polyols” in the present application. The hydroxyl number is thus determined according to the ASTM D4274-16 standard. Determining the hydroxyl index makes it possible in particular to assess the effectiveness of the crosslinking of the formulation.

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.

The term “polyether polyol” means polyols comprising one or more ether functionalities within their molecular structure. The term “polyester polyol” means polyols comprising one or more ester functionalities within their molecular structure.

The expression "chain extender 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 of covalent manner.

The term “isocyanate compound” or “isocyanate” means any compound comprising at least one isocyanate function within their molecular structure. The expressions “polyisocyanate compound” or “polyisocyanate” refer to any organic compound bearing at least two iscoycanate (-NCO) groups within the molecular structure.

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 used for their formulation. They are defined in particular by the isocyanate/polyols ratio (NCO/OH), also called Index, which corresponds to the ratio between the number of isocyanate groups divided by the number of hydroxyl groups of the polyols and any other component carrying such groups.

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

The term “foam” refers to a compound with a three-dimensional expanded type cellular structure. Foam is obtained by the chemical reaction between polyisocyanates and polyols in the presence of other compounds, notably catalysts and expanding agents or blowing agents. The foam thus obtained 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.

“Closed cells storing a gas” as covered by the present technology contain a gas coming from the blowing agent, either by a chemical reaction in the case of a chemical blowing agent, such as dioxide carbon (CO ₂ ) if the chemical agent is water, or a physical expanding agent such as dinitrogen (N ₂ ), dioxygen (O ₂ ), carbon dioxide (CO ₂ ) , hydrocarbons, chlorofluorocarbons, hydrochlorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons or mixtures. The physical blowing agents are in the form of gas or liquid which disperse in the liquid mass of copolymer. During foam formation, the nucleation and growth of bubbles then generate a closed cellular structure storing the gas.

The expressions “expanding agent” or “blowing agent” refer to compounds inducing, through a chemical and/or physical action, an expansion of the composition during the foaming stage.

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.

In the context of this technology, the different ingredients used in the composition of the PUR/PIR foam are defined as a percentage relative to the total weight of polyols. The content of the different ingredients can also be expressed as part by weight (pp) or part by weight relative to the total weight of polyols in the composition.

Polyol blend

The present technology relates to a polyol mixture for the preparation of a polyurethane/polyisocyanurate (PUR/PIR) foam, characterized in that the polyol mixture comprises three (3) different polyols and a chain extender polyol, said different polyols being chosen from polyether polyols and polyester polyols.

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

Polyether polyols

The polyether polyols used in PUR/PIR foam compositions generally have a molecular weight of between approximately 150 g/mol and approximately 1600 g/mol, a functionality of between 3 and 8, and a hydroxyl number of between approximately 250 mg KOH/ g of polyols and approximately 1000 mg KOH/ g of polyols.

In the context of the present 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 of between approximately 200 g/mol and approximately 800 g/mol. Advantageously, the polyether polyols according to the technology have a molecular weight of between approximately 200 g/mol and approximately 600 g/mol, preferably between approximately 300 g/mol and approximately 600 g/mol.

Still, in another embodiment, the polyether polyols have 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 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 of between approximately 550 g/mol and approximately 600 g/mol, preferably between approximately 580 g/mol and approximately 600 g/mol.

The polyether polyols included in the polyol mixture for the preparation of a PUR/PIR foam have a hydroxyl number of between approximately 50 mg KOH/g of polyols and approximately 850 mg KOH/g of polyols. In the context of the present technology, the mixture comprises polyether polyols with a hydroxyl number 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 at approximately 600 mg KOH/g of polyols. In one embodiment, the polyether polyols have a hydroxyl number of between approximately 50 mg KOH/g of polyols and approximately 600 mg KOH/g of polyols, preferably between approximately 100 mg KOH/g of polyols and approximately 600 mg KOH/g of polyols, more preferably between approximately 200 mg KOH/g of polyols and approximately 600 mg KOH/g of polyols. In another embodiment, the polyether polyols have a hydroxyl number 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 approximately 200 mg KOH/g of polyols and approximately 400 mg KOH/g of polyols or between approximately 300 mg KOH/g of polyols and 400 mg KOH/g of polyols. In yet another embodiment, the hydroxyl number of the polyether polyols used in the mixture of polyols for the preparation of 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 number of 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 precisely, the polyether polyols have a hydroxyl number 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 number of the polyether polyols is between approximately 390 mg KOH/g and approximately 500 mg KOH/g of polyols, more precisely between approximately 390 mg KOH/g and approximately 470 mg KOH/g of polyols. .

Polyether polyols can also be defined by their functionality and viscosity. Thus, the polyether polyols used in the mixture of polyols for the preparation of a PUR/PIR foam have a functionality of between 3 and 8, preferably between 3 and 6. The viscosity of the polyether polyols 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 polyols is between 2500 and 3000 mPa.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.

In the context of the present technology, polyether polyols are glycerol-based polyols. More precisely, polyether polyols are polyols based on glycerol and carbohydrates.

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 polyether polyols based on carbohydrates and used in the mixture of polyols for the preparation of a PUR/PIR foam are polyols based on sucrose and/or sorbitol.

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

Such polyether polyols are commercially available. Mention may in particular be made of 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 Polyurethanes.

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

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

Polyester polyols

In addition to polyether polyols, the polyol blend according to the present technology includes polyester polyols.

In the context of the present technology, the polyether polyols have a molecular weight 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. Still, in another embodiment, the polyether polyols have a molecular weight of between approximately 200 g/mol and 900 g/mol, preferably between approximately 200 g/mol and approximately 800 g/mol, more preferably between approximately 200 g/mol. mol and approximately 700 g/mol. More specifically, the polyether polyols used in the mixture of polyols for the preparation of a PUR/PIR foam have a molecular weight of between approximately 250 g/mol and approximately 600 g/mol, preferably between approximately 250 g/mol and approximately 550 g/mol. Advantageously, the molecular weight of the polyether polyols is between approximately 300 g/mol and approximately 550 g/mol, preferably between approximately 400 g/mol and approximately 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 approximately 460 g/mol and approximately 490 g/mol.

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

Concerning the functionality of the polyester polyols used 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.

As with polyether polyols, the viscosity of polyester polyols is 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. Advantageously, the viscosity of the polyether polyols used in the mixture of polyols for the preparation 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.

The polyester polyols used in the polyol blend may be the same or different.

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

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

In one embodiment, the polyester polyols used in the polyol mixture are the STEPANPOL ^® compounds, and more particularly STEPANPOL ^® PS-2352.

Blend of 3 different polyols

In the context of the present technology, the mixture of polyols for the preparation of a PUR/PIR foam comprises a mixture of three (3) different polyols, said polyols being chosen from polyether polyols and polyester polyols previously defined. In one embodiment, the mixture of three (3) different polyols comprises three (3) polyether polyols. In another embodiment, the blend of three (3) different polyols includes two (2) polyether polyols and (1) polyester polyol. In another embodiment, the blend of three (3) different polyols includes 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.

Advantageously, the mixture of three (3) different polyols thus comprises: a first polyether polyol whose molecular weight is between approximately 300 g/mol and approximately 600 g/mol, has a hydroxyl number between approximately 390 mg KOH/g and approximately 470 mg KOH/g of polyols and has 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 number of between approximately 350 mg KOH/g and approximately 360 mg KOH/g of polyols, and a viscosity 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 number of between approximately 230 mg KOH/g of polyols and 250 mg KOH/g of polyols and a viscosity of between 3000 and 4000 mPa.s at 25°C.

Chain extender polyols

The mixture of polyols for the formulation of PUR/PIR foam also includes a chain extender polyol. The mixture of polyols therefore comprises: a mixture of three (3) different polyols chosen 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 have a molecular weight generally less than 350 g/mol and have 2 to 14 carbon atoms.

In the context of the present technology, the chain extender 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, more preferably between approximately 50 g/mol. g/mol and approximately 200 g/mol. Advantageously, the chain extender polyols have a molecular weight of between approximately 100 g/mol and approximately 150 g/mol. In a preferred embodiment, the chain extender polyols have a molecular weight of approximately 134 g/mol.

The hydroxyl number of the chain extender polyols used in the mixture of polyols for the preparation of 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 extender polyols have a hydroxyl number 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, more preferably greater than or equal to approximately 500 mg KOH/g of polyols. In another embodiment, the hydroxyl number of the chain extender polyols is between approximately 500 mg KOH/g of polyols and approximately 1000 mg KOH/g of polyols, preferably between approximately 600 mg KOH/g of polyols and approximately 1000 mg KOH/g of polyols, more preferably between approximately 700 mg KOH/g of polyols and approximately 1000 mg KOH/g of polyols. In yet another embodiment, the hydroxyl number of the chain extender polyols entering into the mixture of polyols 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 extender polyols have a hydroxyl number of 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 precisely between approximately 830 mg KOH/g of polyols and approximately 850 mg KOH/g of polyols. In a preferred embodiment, the hydroxyl number of the chain extender polyol is approximately 837 mg KOH/g of polyols.

An additional characteristic of chain extender polyols is functionality. In the context of the present technology, the chain-extending polyols have a functionality of approximately 2. Advantageously, the chain-extending polyols have a functionality of 2.

The viscosity of the chain extender 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 extender polyols is between 175 and 225 mPa.s, and preferably between 190 and 210 mPa.s at 25°C. Advantageously, the mixture of polyols for the preparation of a PUR/PIR foam comprises a chain extender polyol with a viscosity of 200 mPa.s at 25°C.

Examples of chain extender polyols are bifunctionalized compounds such as diamines or diols, or trifunctionalized compounds such as triamines and triols. By way of example, mention may be made of ethylene glycol, 1,2- and 1,3-propanediol isomers, 1,2- and 1,3-pentanediol isomers, 1,10-decanediol, isomers 1, 2-, 1,3- and 1,4-dihydroxycyclohexane, 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-trihydroxycyclohexane 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.

In one embodiment, the chain extender polyol used in the polyol mixture is a glycol type derivative, in particular chosen from ethylene glycol or propylene glycol derivatives. In a preferred embodiment, the chain extender compound is dipropylene glycol.

Blend of 4 polyols

The chain extender 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 .

The mixture of polyols for the preparation of a PUR/PIR foam comprises, in part by weight relative to the total weight of polyols:

- 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,

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

- from approximately 10 pp to approximately 30 pp of chain extender polyols.

In another embodiment, the mixture of polyols comprises:

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

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

- from approximately 15 pp to approximately 30 pp of chain extender polyols.

Preferably, the mixture of polyols comprises:

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

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

- from approximately 15 pp to approximately 25 pp of chain extender polyols.

More preferably, the mixture of polyols comprises:

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

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

- from approximately 18 pp to approximately 25 pp of chain extender polyols.

Advantageously, the mixture of polyols comprising three (3) different polyols and a chain extender polyol, said different polyols being chosen from polyether polyols and polyester polyols, comprises, partly by weight relative to the total weight of polyols:

- approximately 70 pp of polyether polyols,

- approximately 30 pp of polyester polyols, and

- approximately 20 pp of chain extender polyols

More precisely, the mixture of polyols comprises, in part by weight relative to the total weight of polyols:

- approximately 50 pp of a first polyether polyol,

- approximately 20 pp of a second polyether polyol,

- approximately 30 pp of polyester polyols, and

- approximately 20 pp of chain extender polyols.

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

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

- approximately 10 to approximately 50% polyester polyols, and

- approximately 5 to approximately 35% chain extender polyols.

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

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

- approximately 15 to approximately 35% polyester polyols, and

- approximately 10 to approximately 25% chain extender polyols.

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

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

- approximately 20 to approximately 30% polyester polyols, and

- approximately 15 to approximately 25% chain extender polyols.

Advantageously, the mixture of polyols comprises, as a percentage by weight relative to the total weight of polyols:

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

- approximately 24% polyester polyols, and

- approximately 18% chain extender polyols.

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

Composition of PUR/PIR foam

The mixture of polyols comprising three (3) different polyols and a chain extender polyol, the different polyols being chosen from polyester polyols and polyether polyols, can be used for the preparation of a PUR/PIR foam.

PUR/PIR foam is a cellular structure composed of fine 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, also referred to as blowing agent. This condensation reaction can be catalyzed by compounds of basic and/or nucleophilic nature such as tertiary amines, organometallic complexes or alkali metal complexes.

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 extender polyol, as defined above, and at least one polyisocyanate compound and a catalyst.

Polyisocyanate compounds

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

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.

In the context of this technology, polyisocyanate compounds are diisocyanate compounds, that is to say comprising two isocyanate groups, and can be aliphatic or aromatic.

Polyisocyanate compounds have a viscosity of 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 of between 200 and 1000 mPa.s, preferably between 200 and 800 mPa.s, more preferably between 200 and 600 mPa.s at 25°C.

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

Diisocyanate compounds suitable for the invention are hexamethylene diisocyanate (HDI), isophore diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,4-cyclohexane diisocyanate (CHDI), bis (iscocyanatomethyl)cyclo-hexane (H6XDI,DDI), m-xylene diisocyanate (m-XDI), tetramethyxylylene diisocyanate (TMXDI), toluene diisocyanate compounds (TDI) such as the 2,4- and 2 isomers ,6- toluene diisocyanate (2,4-TDI and 2,6-TDI), diphenylmethylene diisocyanate (MDI) compounds, such as the 4,4'-, 2,4'- and 2,2'- isomers diphenylmethane diisocyanate (2,4'-MDI, 2,4'-MDI and 2,2'-MDI), and dibenzyl diisocyanate compounds, such as 4,4'- and 2,4'-dibenzyl diisocyanate isomers ( 4,4'-DBDI and 2,4'-DBDI).

In one embodiment of the present technology, the polyiscoyanate compound is an aromatic diisocyanate compound, preferably chosen from toluene diisocyanate compounds (TDI), diphenylmethylene diisocyanate compounds (MDI) and dibenzyl diisocyanate compounds (DBDI). Advantageously, the diisocyanate compound is chosen from methylene diphenyl diisocyanate (MDI) compounds.

The diisocyanate compounds can optionally 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.

It is understood in the context of the present technology that the diisocyanate compound may be a mixture of several diisocyanate compounds as defined above.

The presence of the polyisocyanate compound is essential for the formation of the foam in addition to the polyol mixture. The quantity of polyisocyanate is thus at least approximately 70 pp per 100 pp of polyols. In one embodiment, the quantity 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 for 100 pp of polyols. Advantageously, the quantity 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 for 100 pp of polyols.

In another embodiment, the quantity of polyisocyanates is between approximately 80% and approximately 200% by weight relative to the total weight of polyols. In one embodiment, the quantity of polyisocyanates is between approximately 90% and approximately 180%, preferably between approximately 100% and approximately 150%. In another embodiment, the quantity of polyisocyanates in the composition of the PUR/PIR foam 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 approximately 117% and 123% of poly isocyanates, preferably between approximately 118 and approximately 122%, and more preferably between approximately 119 and approximately 121% by weight relative to the total weight of polyols.

The quantity of isocyanate compound can also be defined by the isocyanate/polyols 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 foams obtained are PUR/PIR type foams and have an isocyanate/polyol ratio of between 1 and 1.25.

Catalysts

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

Generally speaking, all compounds making it possible to catalyze the reaction between polyols and polyisocyanates can be used.

The catalysts can be gelation, expansion, hardening, or even trimerization catalysts commonly used in the preparation of PIR foams. We can thus refer to the compounds described in “Kunststoffhandbuch, volume 7, Polyurethane”, Carl Hanser Verlag, ^3rd edition, 1993, chapter 3.4.1.

In the context of the present technology, the catalysts are chosen from organometallic catalysts, and in particular from stannic or tin-based catalysts, bismuth-based catalysts and alkali metal carboxylates.

In one embodiment, the catalysts are chosen 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.

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 even bismuth thiolates. Examples of such compounds are bismuth neodecanoate, bismuth 2-ethylhexanoate, and bismuth octanoate.

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

In another embodiment, the catalyst corresponds to 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 stannic catalyst and potassium octanoate.

Thus, the catalyst used in the composition of the PUR/PIR foam is chosen from stannic catalysts, potassium carboxylates or a mixture of these.

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

Expansion Agents

The composition of the PUR/PIR foam also includes an expansion agent or blowing agent. This element makes it possible to obtain a foam-type alveolar structure and can be of a physical and/or chemical nature. Advantageously, the blowing agent consists of a combination of the two.

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

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

Thus, in one embodiment of the invention, the blowing agent is chosen from hydrofluorocarbons (HFC), 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 hydrofluoroolefins (HFO) such as for example HFO-1234yf ( 2,3,3,3-tetrafluoropropene), HFO-1234ze (1,3,3,3-tetrafluoropropene) or HFO-1233zd (1-chloro-3,3,3-trifluoropropene).

In another embodiment, the expanding agent is a chemical agent, and more particularly carbon dioxide (CO ₂ ) and/or water. In fact, the presence of water as an expanding agent induces the release of CO ₂ which causes the foam to swell. The preferred chemical blowing agent is water.

Physical and chemical blowing agents can be used individually or simultaneously. According to a variant of the invention, the expanding agent comprises a physical agent and a chemical agent. Thus, according to one embodiment, the blowing agent is a mixture comprising a hydrofluorocarbon (HFC), a hydrofluoroolefin (HFO) and/or carbon dioxide (CO ₂ ), in which the hydrofluorocarbon and hydrofluoroolefin compounds are chosen among the compounds previously mentioned. In another embodiment, the blowing agent is a mixture comprising HCF-365mfc and/or HCF-245fa combined with water.

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

In one embodiment, the composition comprises a blowing agent chosen from water, CO ₂ , the fluorinated blowing agents previously defined or a mixture of these.

The quantity of physical expanding 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 quantity 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 quantity of blowing agent in the composition of the PUR/PIR foam is approximately 7% by weight relative to the total weight of polyols.

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

Flame retardants

PUR/PIR foams generally include flame retardants in their composition in order 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.

Compounds used as flame retardants include: the brominated compound Ixol ^® B251, dibromoneopentyl alcohol, tribromoneopentyl alcohol, tetrabromophthalate diol known as PHT4-diol ^TM , 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).

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

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).

In one embodiment, the composition of the foam comprises a flame retardant, advantageously with a quantity of between 5% and 20% by weight relative to the total weight of polyols.

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.

Additives

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

In one embodiment, the composition of the foam comprises at least one additive, preferably a surfactant.

In one embodiment, the formulation comprises at least one surfactant. Surfactants, also called surfactants 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 or non-silicone in nature, or a mixture thereof. Examples of silicone surfactants suitable for the formulation of PUR/PIR foams 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 are oxyethylated alkyl phenol compounds, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, peanut oil, or fatty alcohols. .

Properties of PUR/PIR foam

The composition of the PUR/PIR foam comprising the mixture of polyols, a catalyst, one or more expanding agents and optionally one or more additives is particularly suitable so that, in liquid form, the foam is distributed homogeneously. By “homogeneous” distribution is meant the distribution of the foam in an equivalent or equal manner over the entire support or surface on which the liquid composition is deposited before expansion. Once the foam is obtained, it has homogeneous or equivalent thermal and mechanical properties at all points of the material.

The foam thus has physical and chemical characteristics, as well as particular mechanical properties due in particular to its composition.

Examples of physical and chemical properties are thermal conductivity, density, or compressive strength.

In liquid form or more precisely in emulsion form, the foam presents interesting stability with a creaming time of around 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 color of the composition is observed or when the mixture swells to become a foam . Creaming time is defined according to ASTM D7487.

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

At the same time, PUR/PIR foam has a thermal conductivity of less than 30 mW/m.K, or even less than 27 mW/m.K. Thermal conductivity provides information on the foam's ability to diffuse heat. So, the lower the conductivity, the more insulating the foam is. In one embodiment, the thermal conductivity is between 20 and 27 mW/m.K, preferably between 22 and 26 mW/m.K, more preferably between 23 and 26 mW/m.K. More precisely, the thermal conductivity of the foam according to the invention is between 24 and 26 mW/m.K. In another embodiment, the PUR/PIR foam has a thermal conductivity of approximately 25 mW/m.K.

Concerning the mechanical properties, the foam obtained can be characterized by the compressive stress, the compressive modulus of elasticity, the tensile or shear resistance, the bending resistance, etc.

Compressive stress defines the capacity 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 its size.

In the context of this technology, the PUR/PIR foam has a compressive stress greater than 1.10 MPa, or even greater than 1.20 MPa. In one embodiment, the compressive stress 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. Advantageously, the compressive stress of the PUR/PIR foam is between 1.40 and 1.50 MPa according to the ISO 844 standard.

Process for manufacturing a PUR/PIR foam block

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

PUR/PIR foam is the result of a physicochemical process in which the mixture of polyols 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.

1. mettre en contact au moins un composé polyisocyanate et le mélange de polyols comprenant trois (3) polyols différentes et un polyol allongeur de chaine, lesdits polyols étant choisis parmi les polyols polyéthers et les polyols polyesters, en présence de catalyseurs, d’agents d’expansion et optionnellement d’additifs et de retardateur de flamme,
2. déposer la composition de la mousse obtenue à l’étape (i) sur un support, et
3. laisser solidifier ladite composition après expansion de façon à former un bloc de mousse.

The process for manufacturing a PUR/PIR foam block according to the present technology thus comprises the following steps:

1. bringing into contact at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and a chain extender polyol, said polyols being chosen from polyether polyols and polyester polyols, in the presence of catalysts, expansion and optionally additives and flame retardant,
2. deposit the foam composition obtained in step (i) on a support, and
3. allow said composition to solidify after expansion so as to form a block of foam.

Thus, in a first step, the at least one polyisocyanate compound is brought into contact with the mixture of polyols consisting of 3 different polyols and a chain extender polyol in the presence of catalysts, expanding agents and possibly additives. The mixture is preferably carried out at room temperature and with a so-called low or high pressure machine. So-called low or high pressure machines are well known to those skilled in the art who will be able to determine the machine to use based on the composition and characteristics of the foam.

The mixture obtained and corresponding to the composition of the PUR/PIR foam according to the present technology, is then poured quickly onto a support so that the composition is distributed over the entire said support in a homogeneous manner.

The composition of PUR/PIR foam, initially in liquid form, transforms into foam via chemical reaction. This foam expansion stage can be free or forced.

In one embodiment, the expansion is said to be free, that is to say that no constraint exerted by a volume of closed section is applied. In another embodiment, the expansion of the foam is physically constrained by walls of a double belt laminator, preferably a double belt laminator forming a tunnel of rectangular section with 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.

The foam is then allowed to solidify. This final stage of hardening or solidification can be carried out at high temperatures or at room temperature.

It is understood that in the case where the foam block is prepared by free expansion, it is possible to cut the foam block, so as to obtain a foam block whose dimensions and shape conform to the characteristics sought after. This deburring step can be carried out before or after solidification of said foam block.

1. mettre en contact au moins un composé polyisocyanate et le mélange de polyols comprenant trois (3) polyols différentes et un polyol allongeur de chaine, lesdits polyols étant choisis parmi les polyols polyéthers et les polyols polyesters, en présence de catalyseurs, d’agents d’expansion et optionnellement d’additifs et de retardateur de flamme,
2. déposer la composition de la mousse obtenue à l’étape (i) sur un empilement de fibres de verre ou de mats de verre, et
3. laisser solidifier ladite composition après expansion de façon à former un bloc de mousse.

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, so as to obtain a block of foam fiber. The process then includes the following steps:

1. bringing into contact at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and a chain extender polyol, said polyols being chosen from polyether polyols and polyester polyols, in the presence of catalysts, expansion and optionally additives and flame retardant,
2. deposit the composition of the foam obtained in step (i) on a stack of glass fibers or glass mats, and
3. allow said composition to solidify after expansion so as to form a block of foam.

In this case, the mixture of the PUR/PIR foam composition is poured onto the reinforcing material, so that the formulation permeates the entire thickness of the stack of glass fibers or fiber mats. glass. The content of glass fibers or glass mats can in particular be determined according to the ISO1172 standard.

A particular advantage of the foam composition is that it penetrates quickly and evenly into the reinforcing materials.

The glass fiber mats preferably used consist of continuous glass fiber mats (continuous strand mat) marketed in particular under the Unifilo® or Advantex® brand by Owens Corning.

These glass fibers are assembled 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.

The glass fibers constituting the mats preferably used have a linear mass of 20 to 40 Tex, that is to say 20 to 40 g/km of fibers.

The glass fiber mats have a surface mass preferably between 300 and 900 g/m ² and more advantageously between 300 and 600 g/m ² , more preferably around 450 g/m ² . 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 the total mass.

Depending on the quantity 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.

The glass fibers preferably used according to a second embodiment are advantageously manufactured from roving, that is to say a more or less wide and flattened ribbon made up of glass fibers which are not twisted but kept parallel to each other. . The glass fibers are preferably deposited using the “Webforming” process of Plastech T. T. Ltd.

The glass fibers deposited by this process preferably have a linear mass of 30 to 300 Tex.

Use of PUR/PIR foam

PUR/PIR foams have versatile uses thanks to their insulating and adhesive characteristics. PUR/PIR foams according to the technology are stable, have low thermal conductivity and have excellent mechanical properties such as shear forces, compressive stresses and Young's modulus. At the same time, the foams have a homogeneous distribution over the entire reinforcing material. According to the invention, the foams are particularly suitable for thermal insulation, and more particularly for the insulation of liquefied gas transport tanks, 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 even for pipes and land or port storage tanks.

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

The composition comprising the mixture of polyols, the at least one polyisocyanate compound, the catalyst and optionally additives is deposited on a surface to form a foam block. The deposition rate is calculated based on the height of the desired foam block as well as the desired density. A person skilled in the art will be able to determine these different parameters.

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

These PUR/PIR foam blocks can also be cut transversely at a third of their thickness in order to constitute the two layers of primary and secondary insulation. This single step of cutting from a single block of foam thus makes it possible to simultaneously obtain a primary layer and a secondary layer of insulation, which constitutes a saving of material, due to the low loss, and a saving of time because only one step is necessary for the production of two layers of thermal insulation.

EXAMPLES

Example 1 – Example of composition of a polyurethane/polyisocyanurate foam according to one aspect of the present technology

Compound Quantity
(in pp) Quantity for 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

Claims (18)

Mixture of polyols for the preparation of a polyurethane/polyisocyanurate (PUR/PIR) foam, characterized in that the mixture of polyols comprises three (3) different polyols and a chain extender polyol, said different polyols being chosen from polyols polyethers and polyester polyols. Polyol mixture according to Claim 1, characterized in that the polyether polyols are polyols based on glycerol and sorbitol and/or polyols based on glycerol and sucrose. Polyol mixture according to one of claims 1 or 2, characterized in that the polyester polyols are aromatic polyester polyols, preferably phthalic acid derivatives. Mixture of polyols according to one of claims 1 to 3, characterized in that the chain extender polyol is a glycol type derivative, preferably dipropylene glycol. Polyol mixture according to one of Claims 1 to 4, characterized in that the mixture has a viscosity of between 400 and 800 mPa.s at 25°C. Mixture of polyols according to one of claims 1 to 5, characterized in that it comprises:
- from 28 pp to 100 pp of polyether polyols, and from 18 pp to 67 pp of a first polyether polyol and from 10 pp to 25 pp of a second polyether polyol,
- from 5 pp to 40 pp of a polyester polyol, and
- from 15 pp to 30 pp of a chain extender polyol. Composition of a PUR/PIR foam, characterized in that the composition comprises:
- the mixture of polyols according to one of claims 1 to 6,
- at least one polyisocyanate compound, and
- a catalyst. Composition according to claim 7, characterized in that the composition comprises between 90 pp and 120 pp of polysiocyanate per 100 pp of polyols. Composition according to one of claims 7 or 8, characterized in that the polyisocyanate is chosen from aromatic diisocyanates, preferably, the isocyanate compound is methylene diphenyl diisocyanate (MDI). Composition according to one of claims 7 to 9, characterized in that the catalyst is chosen from stannic catalysts and potassium carboxylates, or a mixture of these. Composition according to one of claims 7 to 10, characterized in that the composition further comprises a blowing agent chosen from water, CO ₂ and fluorinated blowing agents, or a mixture of these. Composition according to 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 of between 110 and 130 kg/m ³ . Polyurethane/polyisocyanurate foam according to one of claims 13 or 14, characterized in that said foam has thermal conductivity of between 24 and 26 mW/m.K. Polyurethane/polyisocyanurate foam according to one of claims 13 to 15, characterized in that said foam has a compressive stress of between 1.30 and 1.50 MPa. Process for manufacturing a polyurethane/polyisocyanurate foam according to claims 13 to 16, said process comprising the steps of:

1. bringing into contact the at least one polyisocyanate compound and the mixture of polyols comprising three (3) different polyols and a chain extender polyol defined according to claims 1 to 6, in the presence of catalysts, expanding agents and optionally a retarder flame and additives, and
2. deposit the composition of the foam obtained in step (i) on a stack of glass fibers or glass mats, and
3. allow said formulation to solidify after expansion so as to form a block of foam.

Use of the polyurethane/polyisocyanurate foam according to claims 13 to 16, or obtained according to the process defined in claim 17 for thermal insulation.