# US 11,999,815 B2 · Process for preparing a block of polyurethane/polyisocyanurate foam of a slab for heat-insulating a tank

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- Number: US 11,999,815 B2
- Document ID: US11999815B2
- Status: Granted
- Kind: B2
- Application number: 17/414,906
- Filed: 2020-01-15
- Published: 2022-03-03
- Granted: 2024-06-04
- Earliest claimed: 2019-01-16
- Assignees: Gaztransport Et Technigaz
- Applicants: Gaztransport Et Technigaz
- Inventors: Guillaume De Combarieu; Patrick Kitzmann; Laetitia Dewolf
- Web page: https://patentgrep.com/patent/US11999815B2

## CPC

- C08G 18/14: {Manufacture of cellular products}
- C08G 18/7664: {containing alkylene polyphenyl groups}
- B63B 25/16: heat-insulated (insulating panelling B63B3/68; heating or cooling B63J)
- C08G 18/4208: {containing aromatic groups}
- C08J 5/043: {with glass fibres}
- C08J 9/0038: {containing phosphorus}
- C08J 9/0085: {Use of fibrous compounding ingredients (C08J9/0076 takes precedence)}
- C08J 9/0095: {Mixtures of at least two compounding ingredients belonging to different one-dot groups}
- C08J 9/125: {Water, e.g. hydrated salts}
- C08J 9/141: {Hydrocarbons}
- C08K 5/0066: {Flame-proofing or flame-retarding additives}
- C08K 5/521: Esters of phosphoric acids, e.g. of H3PO4
- C08L 75/06: from polyesters
- C08G 2101/00: Manufacture of cellular products
- C08G 2110/005: < 50kg/m3
- C08G 2330/00: Thermal insulation material
- C08J 2203/10: Water or water-releasing compounds
- C08J 2203/14: Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
- C08J 2375/04: Polyurethanes
- F17C 2203/0333: Polyurethane
- F17C 2203/0358: in form of panels
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- F17C: VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25)

## Abstract

The present invention relates to a preparation of a block of fiber-reinforced polyurethane/polyisocyanurate foam in which the expansion of the foam is constrained by the walls of a double belt laminator forming a tunnel, the block of fiber-reinforced polyurethane/polyisocyanurate foam being composed of cells storing a gas, advantageously having low thermal conductivity, and exhibiting a density of less than 50 kg·m−3 with a content of fibers Cf representing at least 4% by weight of the block of fiber-reinforced foam, in which the impregnation time of the fibers ti is less than the cream time tc of the polyurethane/polyisocyanurate foam.

## Claims

### Claim 1

A process for the preparation of a block of fiber-reinforced polyurethane and/or polyisocyanurate foam of a thermal insulation slab of a sealed and thermally insulating tank, the block of fiber-reinforced polyurethane and/or polyisocyanurate foam being composed of cells storing a gas and exhibiting a density of less than 50 kg/m3 with a content of fibers Cf representing at least 4% by weight of the block of fiber-reinforced foam, the preparation process comprising:
a) mixing chemical components necessary for obtaining a polyurethane and/or polyisocyanurate foam, said components comprising reactants for obtaining polyurethane and/or polyisocyanurate, optionally at least one reaction catalyst, optionally at least one emulsifier, and at least one blowing agent,
b) impregnating, by gravitational flow of the mixture of chemical components obtained in a), of a plurality of fiber reinforcements chosen from fabrics of fibers and mats of fibers, said fabrics of fibers and said mats of fibers having a length of at least five centimeters (cm), arranged in superimposed layers, in which the plurality of fiber reinforcements extend essentially along a direction perpendicular to the direction of said gravitational flow, the plurality of fiber reinforcements exhibiting a permeability Kc to the mixture of chemical components obtained in a), expressed in m2, equal to:
Kc=(rf2×p3)/(k×τ2×4×Vf2),with
rf=mean radius of the fibers in the fabrics of fibers or mats of fibers, expressed in meters (m),
p=porosity of the fibers in the plurality of fiber reinforcements which is dimensionless with a value between 0 and 1,
k=form factor of the plurality of fiber reinforcements, which is dimensionless, wherein k=1 for a fabric of fibers and k=6 for a mat of fibers,
τ=tortuosity of the fabrics of fibers or mats of fibers constituting the plurality of fiber reinforcements, which is dimensionless,
Vf=volume fraction of the fabrics of fibers or mats of fibers in the plurality of fiber reinforcements, value between 0 and 1, and
c) forming and expanding of the fiber-reinforced polyurethane and/or polyisocyanurate foam,
characterized in that the mixture of chemical components obtained in a) exhibits a dynamic viscosity η, during the impregnation stage b), such that an impregnation time of the fabrics of fibers or mats of fibers ti is less than the cream time tc of the polyurethane and/or polyisocyanurate foam, the impregnation time of the fabrics of fibers and mats of fibers ti being equal to:
ti=(η×em2)/(Kc×ΔP),
ΔP=(Msd×gt×kp),with
η=the dynamic viscosity, expressed in pascal·seconds (Pa·s),
em=sum of the mean thicknesses of the plurality of fiber reinforcements, expressed in meters (m), each fiber reinforcement exhibiting a mean thickness corresponding to the mean of the distances between a plurality of pairs of local extremums of said fiber reinforcement spaced out from one another along a direction of thickness of said fiber reinforcement,
ΔP=pressure gradient, expressed in pascals (Pa),
Msd=surface density of the mixture of chemical components obtained in a), expressed in kilogram per square meter (kg/m2),
gt=9.8 N/kg1, and
kp=0.5.

### Claim 2 (depends on 1)

The process as claimed in claim 1, in which the impregnation time ti observes the following formula with respect to the cream time tc of the polyurethane and/or polyisocyanurate foam:
0
.
5
⁢
0
<
t
i
/
t
c
<
0
.
9
⁢
1
.

### Claim 3 (depends on 1)

The process as claimed in claim 1, in which the expansion of the fiber-reinforced polyurethane and/or polyisocyanurate foam is physically constrained by the walls of a double belt laminator forming a tunnel, thus enclosing the expanding fiber-reinforced foam so as to obtain the block of fiber-reinforced polyurethane and/or polyisocyanurate foam.

### Claim 4 (depends on 3)

The process as claimed in claim 3, in which the positioning of the walls of the tunnel of the double belt laminator is defined so that the constraint on the expansion of the fiber-reinforced polyurethane and/or polyisocyanurate foam results in a volume of fiber-reinforced polyurethane and/or polyisocyanurate foam, at the outlet of the double belt laminator, representing between 85% and 99%, of the expansion volume of an identical fiber-reinforced polyurethane and/or polyisocyanurate foam freely expanded without the constraint of the walls of the double belt laminator.

### Claim 5 (depends on 1)

The process as claimed in claim 1, in which the expansion of the fiber-reinforced polyurethane and/or polyisocyanurate foam occurs freely, without any constraint exerted by a volume of closed section.

### Claim 6 (depends on 5)

The process as claimed in claim 5, in which, following the stage of free expansion of the fiber-reinforced polyurethane and/or polyisocyanurate foam, said fiber-reinforced foam is cut in order to obtain the block of fiber-reinforced polyurethane and/or polyisocyanurate foam.

### Claim 7 (depends on 1)

The process as claimed in claim 1, in which the dynamic viscosity η of the mixture of chemical components obtained in a) is between 30 mPa·s, and 3000 mPa·s, under standard temperature and pressure conditions.

### Claim 8 (depends on 1)

The process as claimed in claim 1, in which at least 60% of said cells storing a gas exhibit a shape elongated or stretched along an axis parallel to the axis of a thickness E of the block of fiber-reinforced polyurethane and/or polyisocyanurate foam.

### Claim 9 (depends on 1)

The process as claimed in claim 1, in which at least 80% of said cells storing a gas, exhibit a shape elongated or stretched along an axis parallel to the axis of a thickness E of the block of fiber-reinforced polyurethane and/or polyisocyanurate foam.

### Claim 10 (depends on 1)

The process as claimed in claim 1, in which the fibers of the fabrics of fibers or mats of fibers are long to continuous and consist of glass fiber, of carbon fiber or any other organic or inorganic material.

### Claim 11 (depends on 1)

The process as claimed in claim 1, in which step b) further comprises a preparation process comprising positioning the fiber reinforcements over an entire width L and impregnating the plurality of fibers reinforcements by the mixture of chemical compounds obtained in a) is performed with a controlled liquid dispenser, simultaneously over the entire width L, in order to obtain the fiber-reinforced polyurethane and/or polyisocyanurate foam.

### Claim 12 (depends on 11)

The process as claimed in claim 11, in which a blowing agent of the at least one blowing agent consists of a physical expanding agent chosen from alkanes and cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals, fluoroalkanes, fluoroolefins having between 1 and 8 carbon atoms and tetraalkylsilanes having between 1 and 3 carbon atoms in the alkyl chain or a mixture of these.

### Claim 13 (depends on 11)

The process as claimed in claim 11, in which the at least one blowing agent comprises water.

### Claim 14 (depends on 12)

The process as claimed in claim 12, in which, the mixing chemical components include at least one polyol compound and during a) a nucleating gas is incorporated in the at least one polyol compound, the nucleating gas representing between greater than 0% and 50% by volume of the at least one polyol compound.

### Claim 15 (depends on 1)

The process as claimed in claim 1, in which, a) mixing the chemical components, the temperature of each of the reactants for obtaining polyurethane and/or polyisocyanurate is between 10° C. and 40° C.

### Claim 16 (depends on 1)

The process as claimed in claim 1, in which there is additionally added to the mixture, in a), an organophosphorus flame retardant, or an inorganic flame retardant.

### Claim 17 (depends on 1)

The process as claimed in claim 1, in which the content of fibers Cf represents between 7% and 15% by weight of the block of fiber-reinforced foam.

### Claim 18 (depends on 1)

A block of fiber-reinforced polyurethane and/or polyisocyanurate foam of a thermal insulation slab of a sealed and thermally insulating tank obtained by the process of claim 1,
characterized in that the fibers are distributed uniformly in such a way that the content Cf varies only by +/−35%, in all zones or portions of said block of fiber-reinforced polyurethane and/or polyisocyanurate foam.

### Claim 19 (depends on 18)

A sealed and thermally insulating tank, said tank consisting of:
a tank integrated in a supporting structure comprising a sealed and thermally insulating tank comprising at least one sealed metal membrane composed of a plurality of metal strakes or metal plates which can comprise corrugations and a thermally insulating slab comprising at least one thermally insulating barrier adjacent to said membrane, or
a tank of type B or a tank of type C according to the definition given by the IGC Code comprising a thermally insulating slab,
characterized in that the thermally insulating slab comprises the block of fiber-reinforced polyurethane and/or polyisocyanurate foam as claimed in claim 18.

### Claim 20 (depends on 19)

A ship for the transportation of a cold liquid product, the ship comprising at least one hull and a sealed and thermally insulating tank as claimed in claim 19, positioned in the at least one hull.