WO2022101472A1

WO2022101472A1 - Light weight fire-resistant board and laminate for marine applications

Info

Publication number: WO2022101472A1
Application number: PCT/EP2021/081679
Authority: WO
Inventors: Pierre PEYRON; Emmanuel Vial; Ilja DOROSCHENKO
Original assignee: Etex Building Performance International Sas; Etex Building Performance Gmbh
Priority date: 2020-11-16
Filing date: 2021-11-15
Publication date: 2022-05-19
Also published as: EP4244053A1

Abstract

The present invention concerns a fire-resistant board at least classified B15, comprising a core (1c) sandwiched between two facers (1f) and comprising at least 80 wt.% calcium sulphate dihydrate and at least 2.3 kg / m³ glass fibres. A groove (3) extends along each of the first and second longitudinal edges for forming a spline joint with a second board. The boards can be produced in large dimensions of up to 3050 mm length and higher, while still being hand able due to their low density of 0.35 and 0.65. The present invention also concerns a laminate formed by a board as defined supra sandwiched between two high-pressure layers (HPL).The laminates can be joined with one another by spline joints to form a partition system particularly suitable for forming bulkheads, deckheads, and partitions in general, as well as floors and ceilings, pieces of furniture, and the like in sea-going vessels (= ships) and offshore platforms.

Description

LIGHT WEIGHT FIRE-RESISTANT BOARD AND LAMINATE FOR MARINE APPLICATIONS

TECHNICAL FIELD

[0001] The present invention concerns lightweight, fire resistant boards and laminates comprising a core made of calcium sulphate dihydrate (gypsum), which are particularly suitable for forming bulkheads, deckheads, and partitions in general, as well as floors and ceilings, pieces of furniture, and the like in marine applications, including sea-going vessels (= ships) and offshore platforms. Boards and laminates used in marine applications have standard dimensions which can reach 2400 mm and up to 3050 mm in length. The boards must therefore be light in weight to ease transportation and handling and must be fire resistant. The boards of the present invention are rated at least B15 according to IMO Res.307(88) FTP Code 2010 The present invention also concerns partitions systems composed of two or more laminates joined to one another by spline joints.

BACKGROUND OF THE INVENTION

[0002] All fire protection equipment including bulkheads, deckheads, and partitions in general, as well as floors and ceilings, pieces of furniture, and the like, to be installed onto European flagged vessels must now fulfil the Marine Equipment Directive (MED) 2014/90/EU. This ensures that all European flagged vessels meet a common standard of safety and performance. The foregoing directive is compatible with the SOLAS Convention, which is generally regarded in the maritime industry as the most important of all international treaties concerning the safety of merchant ships. MED includes the following fire protection classification, rated A-, B-, and C-class.

• C-class is the minimum level of fire protection requiring panels to be non-combustible: The non-combustibility test is done according to ISO 1182:1990 Fire tests- Building materials, except that instead of Annex A “criteria for evaluation" of this standard, all the following criteria shall be classified:

(a) The average furnace thermocouple temperature rises as calculated in 8.1 .2 of ISO 1182 does not exceed 30°C;

(b) The average specimen surface thermocouple temperature rises as calculated in 8.1 .2 of ISO 1 182 does not exceed 30°C;

(c) The mean duration of sustained flaming as calculated in 8.2.2 of ISO 1 182 does not exceed 10 s; and

(d) The average mass loss as calculated in 8.3 of ISO 1182 does not exceed 50%;

• B-Class panels must satisfy the requirements defined for C-class and must additionally be tested to IMO Res. 307(88) FTP Code 2010 and prevent the passage of smoke and/or flames and maintain their integrity for a minimum of 30 minutes. The number following the B indicates the insulation time in minutes.

• A-Class barriers are also tested to IMO Res. 307(88) FTP Code 2010 and prevent the passage of smoke and/or flames and maintain their integrity for a minimum of 60 minutes. The number after the ‘A’ indicates the required insulation time in minutes.

This classification is then ascertained and attested by a Notified Body.

[0003] Since in most applications, at least one main surface of the panels is visible, the panels are generally provided with a layer laminated on one or both main surfaces. Besides a decorative effect, the layer also enhances the mechanical properties, in particular the flexural properties.

[0004] Panels used in marine applications may have dimensions of 2400 mm and even of 3050 mm in length. Weight of fire protection equipment in vessels is of major importance as it impacts drastically the fuel consumption of the ships. Furthermore, because of the large dimensions of the panels, weight is a drawback for transportation and handling during the mounting of the partitions.

[0005] To date, two major materials are mostly used as major components of such boards, generally forming a core of a laminated panel:

• intumescent materials, such as vermiculite and

• metal silicate, in particular alkali metal- and alkali earth metal-silicates, such as sodium- or calcium-silicate, which combine fire resistance and mechanical properties required for such applications.

[0006] For example, WO2017137599 describes panels comprising a core made of metal silicates for marine applications. W02004110951 describes multilayer panels comprising both metal silicate and vermiculite.

[0007] Gypsum or calcium sulphate dihydrate is an endothermic material generally having good fire resistance. More specifically, when heated to 100°C, gypsum undergoes a decomposition reaction in which 75% of the crystalline water is driven off as steam as the gypsum converts to hemihydrate,

CaSO₄2H₂O ->• CaSO₄ T2H2O + 1 % H₂O (1 )

[0008] Further heating to 120°C drives off the remaining crystalline water hemihydrate converts to anhydrite (= calcium sulphate),

CaSO₄ T2H2O ->• CaSCU + ¹/₂H₂O (2)

[0009] For example, EP1303672 and US2003/0138614 describe fire-resistant gypsum boards (or plasterboards). In both documents, the densities of the plasterboards are, however, larger than 0.8, which is too high for marine applications. Lighter plasterboards can be obtained by adding a foaming agent. The fire- resista nee properties decrease proportionally with decreasing density, since the amount of water required for the reactions (1) and (2) decreases accordingly. Even if they remain satisfactory in terms of heat absorption, the mechanical integrity of the panels drops too low to fulfil the requirements for being rated B or A.

[0010] For the foregoing reasons, gypsum boards (or plasterboards) have, to date, not been used extensively for marine applications. The present invention concerns a light weight calcium sulphate dihydrate panel structure which is rated B15 according to IMO Res. 307(88) FTP Code 2010 and can be produced in large dimensions of 3050 mm length and more. The panels can be used in marine applications in lieu of metal silicate panels, or of vermiculite containing panels. These and other advantages of the present invention are presented in continuation.

SUMMARY OF THE INVENTION

[0011] The present invention is defined in the appended independent claims. Preferred embodiments are defined in the dependent claims. In particular, the present invention concerns a board having a fire classification according to IMO Res. 307(88) FTP Code 2010 of at least B15, and comprising,

• a core having a rectangular geometry, comprising a first main surface parallel to and separated from a second main surface by a thickness comprised between 18 and 25 mm, preferably between 19 and 22 mm and forming a peripheral edge comprising first and second longitudinal edges of length (L) of at least 2500 mm, preferably at least 2900 mm, more preferably at least 3050 mm extending along a longitudinal axis (X), normal to and separated from one another by first and second transverse edges extending along a transverse axis (Y) normal to the longitudinal axis (X), and

• a facer, preferably non-combustible covering the first and the second main surfaces wherein the facer (1f) comprises a non-woven mat having a side facing the core having a surface roughness (Ra) ranging from 20 pm to 60 pm measured according to NF EN ISO 4287-2009,

[0012] The core of the board comprises at least 80 wt.%, preferably at least 90 wt.%, more preferably at least 95 wt.% of calcium sulphate dihydrate relative to the total weight of the core. The density of the core is comprised between 0.35 and 0.65, preferably between 0.50 and 0.60. The core comprises between 2.3 kg I m³ and 6.3 kg I m³, preferably between 2.8 kg I m³ and 5.0 kg I m³, more preferably between 3.1 kg I m³ and 3.9 kg I m³ of glass fibres.

[0013] A groove extends along each of the first and second longitudinal edges, each groove having an opening width (w) measured normal to the first and second main surfaces of 2 mm + 0.3 mm, and a depth (d) measured parallel to the first and second main surfaces comprised between 25 and 60 mm, preferably between 30 and 50 mm.

[0014] Beside calcium dihydrate and glass fibres, the core preferably comprises starch in an amount comprised between 3.15 and 6.30 kg / m³ of the core, polyvinyl alcohol (PVOH), and a foaming agent. The core preferably comprises no calcium silicate and/or no vermiculite or not more than 3 wt.% vermiculite relative to the total weight of the core.

[0015] . The facer is preferably made of a composite material comprising fibres including cellulose fibres and glass fibres. For example, the composite can comprise optionally polyester fibres, and can comprise a binder resin, preferably a vinyl-acrylate copolymer or ethylene vinyl acetate.

[0016] A displacement (8) of the board of length, L = 3000 mm, width, W = 1200 mm, and thickness, t = 19 mm, loaded in three point bending, is preferably at least equal to 160 mm, more preferably at least equal to 180 mm. Alternatively, a displacement (8) of the board clamped at a length, L = 3000 mm, width, W = 1200 mm, and thickness, t = 19 mm, loaded in three point bending, is preferably at least equal to 160 mm, more preferably at least equal to 180 mm, without failure of the gypsum board core.

[0017] The present invention also concerns a laminate comprising a board as defined supra, wherein the first and the second main surfaces are covered by a high pressure laminate (HPL). The thickness of the HPL is preferably comprised between 0.6 and 1 .2 mm. The HPL can comprise cellulose fibres impregnated in a resin.

[0018] A displacement (8) of the laminate of length, L = 3000 mm, width, W = 1200 mm, and thickness, tL = 19 + 2 mm, loaded in three point bending, is preferably at least equal to 120 mm, preferably at least equal to 145 mm, without failure of the gypsum board core.

[0019] The present invention also concerns a partition system comprising first and second laminates as defined supra, which are joined to one another along a first longitudinal edge thereof by at least one spline fitted in the grooves of the first longitudinal edge of each of the first and second laminate forming a spline joint between the two laminates.

[0020] Finally, the present invention also concerns a use of a board, a laminate, or a partition system as defined supra for forming panels in marine applications, including bulkheads, walls, ceilings, pieces of furniture in ships or off-shore platforms.

BRIEF DESCRIPTION OF THE FIGURES

[0021] For a fuller understanding of the nature of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings in which:

Figure 1(a): shows a first embodiment of a laminate according to the present invention.

Figure 1 (b): shows a second embodiment of a laminate according to the present invention.

Figure 2(a): shows a kit-of-parts of two laminates according to the present invention and a spline for joining them.

Figure 2(b): shows a partition system according to the present invention obtained by joining the two laminates by the spline of the parts of the kit illustrated in Figure 2(a).

Figure 3(a): shows a perspective view of a board according to the present invention.

Figure 3(b): shows a cross-section of the board of Figure 3(a).

Figure 3(c): shows a perspective view of a laminate according to the present invention.

Figure 3(d): shows a cross-section of the laminate of Figure 3(c).

Figure 4(a): shows a three-point bending set-up in a view on a plane (X, Z).

Figure 4(b): shows the three-point bending set-up of Figure 4(a) in a view on a plane (X, Y).

Figure 4(c): shows a typical stress-displacement three-point bending curve measured on a laminate (1 L) and on a board (1).

Figure 5(a): plots the three-point bending flexural modulus (G) as a function of glass fibre content for the boards of example 1 according to the present invention.

Figure 5(b): plots the three-point bending maximum stress and maximum displacement as a function of glass fibre content for the boards of example 1 according to the present invention.

Figure 6(a): plots the three-point bending flexural modulus (G) of boards (1) and laminates (1 L) of example 1 according to the present invention.

Figure 6(b): plots the three-point bending maximum stress of boards (1) and laminates (1 L) of example 1 according to the present invention.

Figure 6(c): plots the three-point bending maximum displacement of boards (1) and laminates (1 L) of example 1 according to the present invention.

Figure 7(a): plots the three-point bending flexural modulus (G) as a function of density of boards (1) and laminates (1 L) of EX1 , CEX2, and CEX3.

Figure 7(b): plots the three-point bending maximum stress as a function of density of boards (1) and laminates (1 L) of EX1 , CEX2, and CEX3.

Figure 7(c): plots the three-point bending maximum displacement as a function of density of boards (1) and laminates (1 L) EX1 , CEX2, and CEX3.

Figure 8(a): shows the locations of the thermocouples applied on the cold surface of a partition for fire testing.

Figure 8(b): plots the time dependence of the temperatures of the hot surface (H) exposed to heat of a furnace and cold surface (C) of a board of EX1 according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

BOARD (1)

[0022] As shown in Figures 3(a) and 3(b), the present invention concerns a light weight, fire-resistant board (1) having a fire classification according IMO Res. 307(88) FTP Code 2010 of at least B15. The board comprises,

• a core (1 c) having a rectangular geometry, comprising a first main surface parallel to and separated from a second main surface by a thickness (tc) comprised between 18 and 25 mm, preferably between 19 and 22 mm and forming a peripheral edge comprising o first and second longitudinal edges of length (L) of at least 2500 mm, preferably at least 2900 mm, more preferably at least 3050 mm extending along a longitudinal axis (X). The length of the first and second longitudinal edges is preferably not greater than 3500 mm. The first and second longitudinal edges are normal to and separated from one another by o first and second transverse edges extending along a transverse axis (Y) normal to the longitudinal axis (X), and

• a non-combustible facer (1f) covering the first and the second main surfaces.

[0023] The core (1 c) comprises at least 80 wt.%, preferably at least 90 wt.%, more preferably at least 95 wt.% of calcium sulphate dihydrate relative to the total weight of the core. The core preferably comprises not more than 99 wt.% calcium sulphate dihydrate relative to the total weight of the core. These amounts take into account any mineral present in a gypsum of natural origin. Calcium sulphate dihydrate is clearly the main component of the core (1 c), so that the core can be defined as a gypsum core. The core (1 c) is very light weight with a density comprised between 0.35 and 0.65, preferably between 0.50 and 0.60. To enhance the mechanical properties, as well as maintaining the fire- resista nee properties, the core also comprises between 2.3 kg I m³ and 6.3 kg I m³, preferably between 2.8 kg I m³ and 5.0 kg I m³, more preferably between 3.1 kg / m³ and 3.9 kg I m³ of glass fibres.

[0024] The board (1) comprises a groove (3) extending along each of the first and second longitudinal edges of the core (1 c). Each groove has,

• an opening width (w) measured normal to the first and second main surfaces of 2 mm + 0.3 mm, and

• a depth (d) measured parallel to the first and second main surfaces comprised between 25 and 60 mm, preferably between 30 and 50 mm.

[0025] the grooves (3) are used for forming a spline joint between two adjacent boards by insertion of a spline (13). The core (1 c) preferably does not comprise any calcium silicate. The core also preferably does not comprise any vermiculite or does not contain more than 3 wt.% vermiculite relative to the total weight of the core. Beside calcium dihydrate and glass fibres, the core (1 c) comprises starch in an amount comprised between 3.15 and 6.30 kg I m³ of the core, polyvinyl alcohol (PVOH), and a foaming agent.

[0026] The starch may be natural starch; or a starch derivative such as a substituted starch. The starch may be derived from e.g. potato, tapioca, or corn. Starches are often used to improve the adhesion of a facer to a core. It is further thought that substituted starches act as efficient binders for the inorganic phase of plasterboards, e.g. gypsum, thus increasing the core strength of the plasterboard. Preferred substituted starches include, but are not limited to, hydroxyethylated starch, hydroxypropylated starch, and/or acetylated starch. Preferably, the starch is insoluble in cold water, but dissolves at a higher processing temperature during forming, setting, or drying of the plasterboard. This is thought to limit excessive migration of the starch, so that it remains in the plasterboard core, to provide a binder for the gypsum crystals.

[0027] The PVOH comprises non-fibrous polyvinyl alcohol (PVOH). The addition of PVOH may result in an improved bonding between the core and the liners and may further result in an improved mechanical strength.

[0028] For example, a tc = 18.8 mm thick core (1 c), for forming a t = 19 mm thick board (1), can be produced by setting with 6491 g / m² water the composition listed in Table 1 . The glass fibres preferably are in the form of chopped fibres. The foaming agent is required for forming gas bubbles in the core and thus reducing the density accordingly. Of course, foam forming also reduces the mechanical properties of the core (1 c). This is particularly true at the level of the grooves. A groove of 2 mm width (w) extending along the longitudinal edges of a tc = 18.8 mm thick core (1 c) forms two tongues, on either side of the groove (3), which are only about 8 mm thick each. This creates a weakness in the board which requires strengthening as otherwise it would weaken the integrity of a spline joint formed therebetween. To strengthen the tongues, a higher amount of glass fibres is used than is usually applied in the art. The resulting board is formed by core (1 c) having a density of 0.5 kg/m³ which is sandwiched between two facers; a facer (1 f) applied on each of the first and second main surfaces.

Table 1: composition of the slurry for forming a core by addition of 6491 g/m² water

PVOH = polyvinyl alcohol

PCE = polycarboxylate-polyether

[0029] The slurry composition of Table 1 sets to form an 18.8 mm thick core having the composition listed in Table 2, wherein the concentrations are expressed in kg / m³ of core.

Table 2: composition of the core obtained by setting of the slurry composition of Table 1

[0030] In a preferred embodiment, the core comprises no phosphate-containing component and preferably no siloxane either.

[0031] The facers (1f) must be at least non-combustible, and preferably fire-resistant for use in many marine applications wherein fire- resista nee of the boards is a prerequisite. The facers (1f) can comprise a non-woven mat. The surface of the non-woven mat facing and adhering to the core (1 c) can have a surface roughness Ra ranging from 20 pm to 60 pm. The Ra surface roughness parameter corresponds to the arithmetic mean of the absolute values of the profile deviations from the mean line of the roughness profile. The surface roughness is a parameter well known in the art and can be measured using an optical profilometer. In particular, the Ra surface roughness parameter is measured in accordance with NF EN ISO 4287-2009, with a measurement length of 3.5 mm, and 500 measuring points per mm. The reported value is the mean of 6 measurements. In a preferred embodiment, the facers (1f) are made of a composite material comprising fibres including cellulose fibres, glass fibres, and optionally polyester fibres, preferably in the form of nonwoven mats, and a binder resin, preferably a vinyl-acrylate copolymer or ethylene vinyl acetate.

LAMINATE (1 L)

[0032] The board (1) of the present invention is optimized for forming a laminate 1 L) comprising a board (1) as described supra, wherein the first and / or the second main surfaces are covered by a high pressure laminate (HPL) (1 hpl), as illustrated in Figures 1 (a) &1 (b) and 3(c)&3(d). The HPL’s (1 hpl) have a double function. On the one hand they have a decorative function, for applications wherein at least one main surface is visible. On the other hand, as shown in Figures 6(a) to 6(c), the HPL’s increase substantially the mechanical properties of the laminates (1 L) compared with the boards (1) without HPL. In particular, bending strength, tensile strength, and hardness can be substantially enhanced with the application of HPL’s on at least one, preferably both main surfaces of the board (1).

[0033] A HPL (1 hpl) can typically have a thickness (th) comprised between 0.6 and 1.2 mm, preferably between 0.7 and 1.0 mm. For example, the HPL can comprise cellulose fibres impregnated in a resin.

[0034] As will be shown in the Example and illustrated in Figure 6(c), a displacement (8) of the board (1) of length, L = 3050 mm and clamped at a distance of 3000 mm, width, W = 1200 mm, and thickness, t = 19 mm, loaded in three point bending in a set-up as illustrated in Figures 4(a) and 4(b), can be at least equal to 160 mm, preferably at least equal to 180 mm. The corresponding laminate (1 L) of length, L = 3050 mm and clamped at a distance of 3000 mm, width, W = 1200 mm, and thickness, tL = 19 + 2 mm, loaded in three point bending, has a maximum displacement (8) at least equal to 120 mm, preferably at least equal to 145 mm, without failure of the gypsum board core (1 c). When sufficiently flexible, the laminates may slip out of the clamps before failure. Figure 4(c) illustrates an example of three-point bending stress (CT) VS displacement (8) for a board (1) and a laminate (1 L).

PARTITION SYSTEM

[0035] The laminates (1 L) of the present invention are suitable for forming partitions between two volumes of large dimensions within a sea-going vessel (e.g., a ship) and in an offshore platform. Thanks to their low densities, the laminates are available in large dimensions, with lengths (L) along the longitudinal direction (X) of up to 3050 mm and higher, and widths (W) in the transverse direction (Y) of up to 1320 mm and higher. In order to form a partition wall or bulkhead of large dimensions, however, several laminates must be joined side-by-side. It is known to use H-shaped clamps to sandwich a laminate between two jaws on each side of the H-clamp. This solution has, however, the drawback that the clamps are visible on the exposed surfaces of the thus formed partition wall. A solution to join two laminates side-by-side without showing the joining system is to use spline joints as illustrated in Figure 2(b).

[0036] Figure 2(a) shows the elements for forming a partition system (11) according to the present invention, comprising first and second laminates (1) as described supra, which are joined to one another along a first longitudinal edge thereof by a spline (13) fitted in the grooves (3) of the first longitudinal edge of each of the first and second laminate (1) forming a spline joint between the two laminates (1). The resulting partition system (11) joined by a spline (13) is illustrated in Figure 2(b). A spline (13) is an elongated blade which fits snugly in the grooves (3) extending along the longitudinal edges of the boards (1) forming the corresponding laminates to be joined. The cross-section of the spline (13) can be substantially rectangular, with dimensions of the thickness and width fitting the corresponding depth (d) and width (w) of the grooves. Alternatively, the spline can be in the form of a profile comprising convex portions acting as springs as they are inserted into a groove. The surface of the spline can be structured to grip the walls of the groove it is inserted in.

[0037] The spline can be made of metal, such as steel or aluminium. Alternatively, it can be made of polymer, preferably fibre reinforced polymer. For example, the spline can be produced by pultrusion of a glass fibre reinforced profile.

[0038] In one embodiment illustrated in Figure 1 (b), the grooves (3) extend also along the transverse edges of the laminates (1 L). This allows the formation of spline joints between two laminates along any one of their longitudinal or transverse edges. This can be very useful when using the partition system for forming ceilings or floors.

[0039] The grooves (3) required along the longitudinal edges of the laminates to form spline joints locally weaken the mechanical integrity of the laminate. For example, in a tL = 19 + 2 mm laminate the grooves form thin tongues on either side thereof of only about 8 to 10 mm thickness. By increasing the content of glass fibres to between 2.3 kg I m³ and 6.3 kg I m³, preferably between 2.8 kg I m³ and 5.0 kg I m³, more preferably between 3.1 kg I m³ and 3.9 kg I m³, the resistance of the tongues becomes sufficient for forming a partition system according to the present invention for use in marine applications.

[0040] Each of the board (1), the laminate (1), and the partition system (11) of the present invention are optimally suited for forming panels in marine applications, including bulkheads, walls, ceilings, pieces of furniture in ships or off-shore platforms. EXAMPLES

[0041] The following examples and comparative examples illustrate the present invention.

Example 1 (= EX1 , EX1.120)

[0042] A board (1) according to the present invention was produced by depositing a settable slurry composed of the composition listed in Table 1 formed with 6491 g / m² water onto a sheet of facer (1f). A second facer (1f) was applied on top of the settable slurry to form a sandwich structure and allowing the gypsum in the slurry to set to form the core (1 c) of the board (1) of composition listed in Table 2. Excess water can be evaporated in an oven. The facer is a non-woven facer having a surface roughness Ra ranging from 20 pm to 60 pm on the side facing the core of the board. It is available from Ahlstrom Munksjb.

[0043] A laminate (1 L) according to the present invention was produced by applying a HPL (1 hpl) on both first and second main surfaces of the board (1) described supra. Glue was used to adhere the HPL’s to the main surfaces of the boards. The glue was polyvinyl acetate.

[0044] When the boards of Example 1 (= EX1) contain 60 g / m² of glass fibres relative to the total weight of the core (cf. Table 1), boards identical to the ones of EX1 , but with 120 g / m² glass fibres were produced and are referred to as Example 1 .120 (= EX1 .120).

Comparative Example 1 (= CEX1)

[0045] Comparative Example 1 is a board and laminate identical to EX1 and EX1.120, but with 30 g / m² glass fibres instead of 60 and 120 g / m², respectively.

[0046] Comparative Example 2 (= CEX2)

[0047] Comparative Example 2 is a non-combustible board made of vermiculite produced by Fipro under the trade name Fipro Light 400.

Comparative Example 3 (= CEX3)

[0048] Comparative Example 3 is a fire-resistant board made of calcium silicate produced by Etex under the trade name Promarine.

Testing

[0049] The boards and laminates (i.e., board + HPL) of Example 1 (EX1 , and EX1.120) and comparative Examples 1 to 3 (CEX1 to CEX3) were tested as follows.

[0050] Weight, thicknesses (t, tc), and densities were measured.

[0051] Three-point bending tests were performed on real size 3050 x 1200 mm panels with a 3000 mm distance between clamps. The set-up is illustrated in Figures 4(a) and 4(b). A force is applied at a constant rate along a mid-line parallel to the transverse edges at half distance between the clamps. The displacement (8) was measured as a function of applied force until failure, or until the panel got unclamped. An example of stress vs displacement graph is illustrated schematically in Figure 4(c) for a board (1) and a laminate (1 L).

[0052] Fire resistance tests, including insulation and integrity characterizations, were performed on a partition wall closing one side of an oven and made of three boards assembled with spline joints with the first main surface facing the interior of the oven and referred to as the hot surface (H), whilst the second surface, facing away from the oven is referred to as the cold surface (C). Seven thermocouples (T1-T5, and Tj6, Tj7) were arranged on the cold surface (C) of the partition wall as illustrated in Figure 8(a). Five thermocouples (T1-T5) were positioned at various locations on the boards, and two thermocouples (Tj6, Tj7) were positioned at the spline joints. The oven was heated to a final temperature of 900°C and the hot surface of the partition wall closing the side of the oven, was exposed to the temperature of the oven, as shown in Figure 8(b), curve labelled (H). The temperature of the cold surface of the partition, opposite the hot surface, was measured with the seven thermocouples. Figure 8(b) shows the resulting curves measured with the five thermocouples T1-T5 located on the boards (cf. Figure 8(b), curve labelled (C)).

[0053] To reach a class B15, the temperature increase (AT = T(t) - T0, with TO, the initial temperature at time t = 0) measured at the cold surface (C) by each of the five thermocouples T1-T5 located on the boards must remain below 180°C for a period of at least 15 min, and the average temperature increase measured over the five thermocouples must remain below 140°C for the same duration. The temperature increase measured by the two thermocouples (Tj6, Tj7) arranged at the spline joints must remain below 225°C for at least 15 min.

[0054] The integrity of the partition must be assessed after 30 minutes of heating. The integrity requirement is fulfilled if each of the following tests are passed:

• flaming: there shall be no flaming on the cold surface

• cotton-wool pad: there shall be no ignition of a cotton-wool pad exposed to the cold surface for 30 s, due to hot gases coming from cracks and openings; and either

• gap inspection gauge #1 : a 6 mm thick inspection gauge must not be able to penetrate into any opening on the cold surface (C), cross through the thickness of the partition until reaching the hot surface (H), and to move along the opening over a distance of more than 150 mm; or

• gap inspection gauge #2: a 25 mm thick inspection gauge must not be able to penetrate into any opening on the cold surface (C), cross through the thickness of the partition until reaching the hot surface (H).

Results

[0055] Table 3 lists the results of the three point bending tests performed on boards (1) of CEX1.30, EX1 , and EX1.120, loaded with 30, 60, and 120 g / m² of glass fibres, respectively. These results are illustrated graphically in Figures 5(a) and 5(b), plotting the flexural modulus (G), the maximum stress (c>max) and maximum displacement (Smax) as a function of glass fibre (GF) contents. It can be seen in Figure 5(a) that, as could be expected, the flexural modulus (G) increases linearly with increasing amount of glass fibres. Figure 5(b), however, shows that the maximum displacement is substantially independent of the glass fibre contents. Overall, the three point bending results are acceptable for marine applications independently of the glass fibre contents. Because of the presence of grooves (3), however, it was observed that with a glass fibre content of 30 g / m² the tongues extending on either side of the grooves were not strong enough to form a satisfactory spline joint for a partition system according to the present invention. With glass fibres contents above 120 g / m², production of the boards became more difficult, with no corresponding added value overcoming such production issues.

Table 3: Three point bending results in boards (1) according to CEX1, EX1, and EX1.120

[0056] Table 4 lists the results of three-point bending measured on boards (1) and laminates (1 L) of EX1 , CEX2, and CEX3. Figures 6(a) to 6(c) plot the flexural modulus (G), maximum stress (cymax) and maximum displacement (Smax) for the boards (1) of EX1. The maximum displacement (Smax) for the laminates (1 L) of EX1 is indicated as N.A. in Figure 6(c), because 8max could not be measured properly as the laminates (1 L) slipped off the clamps without failure of the cores (1 c). It can be seen that the HPL’s substantially enhance the mechanical properties of the laminates (1 L) (right columns) compared with the boards (1) devoid of HPL (left columns). Figure 6c plot the maximum displacement (Smax) for the board. A higher value of the max displacement is observed for the board according to the invention. This capacity to be deformed without breaking is believed to explain partially the excellent fire resistance behaviour of the boards. Table 4: results of the tests performed on the boards and laminates of EX1, CEX2, and CEX3

⁽¹⁾ Not measurable because the samples slipped off the clamps without failure of the cores, due to their excellent flexibility.

[0057] Figures 7(a) to 7(c) plot the flexural modulus (G), maximum stress (c>max) and maximum displacement (8max) measured on the boards (white circles) and laminates (black circles) of EX1 , CEX2 and CEX3 as a function of their densities (with the exception of Smax.of the laminate (1 L) of EX1 , which could not be measured). It can be seen that the boards (1) and laminates (1 L) of the present invention (EX1) have agreeable mechanical properties that compare quite well, (albeit a little lower) with the ones of CEX2 and CEX3, with a density which is substantially lower than the comparative examples CEX2 and CEX3. Note that the board of CEX2 (made of vermiculite) is very brittle; and hence requiring more care upon handling, typically for applying HPL’s, as some flexibility is required for this operation. Calcium silicate boards of CEX3 yield the best mechanical properties but the density of the calcium silicate boards is substantially higher than the boards according the invention (viz., 0.86 versus 0.5). This negatively impacts the potential use of calcium silicate board having a length (L) higher than 2000 mm.

[0058] Figure 8(b) plots the temperature as a function of time of the hot surface (H) which is exposed to the heat of the furnace, and of the cold surface (C) which faces away from the interior of the furnace. The black circles B15 and B30 indicate the minimum time required for each of the five thermocouples (T1-T5) applied on the cold surface (C) of the boards to reach 180°C to be classified B15 and B30, viz., after 15 min and 30 min, respectively. The white circles B15 and B30 indicate the minimum time required for the average temperature measured by the five thermocouples (T1-T5) to reach 140°C to be classified B15 and B30 (both conditions must be fulfilled in combination to be classified B15 or B30). It can be seen that the board (1) of EX1 of the present invention is well below both black and white circles labelled B15, therefore satisfying these criteria for being classified B15. It is, however; above the black and white circles labelled B30, as the board (1) cannot maintain a temperature at all five points below 180°C for 30 min.

[0059] The boards (1) and laminates (1 L) according to the present invention offer an easy to process solution for lightweight fire-resistant applications. The low density and good mechanical properties of the boards and laminates of the present invention offer new perspectives of panelling high-ceilinged volumes in ships and in the marine field in general. The boards and laminates are particularly suitable for forming bulkheads, deckheads, and partitions in general, as well as floors and ceilings, pieces of furniture, and the like in sea-going vessels (e.g., ships) and offshore platforms. The combination of their lightweight, fire- resista nee, and mechanical properties make them particularly suitable for replacing state of the art vermiculite panels and calcium silicate panels, which are heavier and substantially more expensive.

Claims

1. Board (1) comprising,

• a core (1 c) having a rectangular geometry, comprising a first main surface parallel to and separated from a second main surface by a thickness comprised between 18 and 25 mm, preferably between 19 and 22 mm and forming a peripheral edge comprising first and second longitudinal edges of length (L) of at least 2500 mm, preferably at least 2900 mm, more preferably at least 3050 mm extending along a longitudinal axis (X), normal to and separated from one another by first and second transverse edges extending along a transverse axis (Y) normal to the longitudinal axis (X), and

• a facer (1 f) preferably a non-combustible .covering the first and the second main surfaces , wherein the facer (1f) comprises a non-woven mat having a side facing the core (1 c) having a surface roughness (Ra) ranging from 20 pm to 60 pm measured according to NF EN ISO 4287-2009, wherein the core (1 c),

• comprises at least 80 wt.%, preferably at least 90 wt.%, more preferably at least 95 wt.% of calcium sulphate dihydrate relative to the total weight of the core,

• has a density comprised between 0.35 and 0.65, preferably between 0.50 and 0.60, and

• comprises between 2.3 kg I m³ and 6.3 kg I m³, preferably between 2.8 kg I m³ and 5.0 kg I m³, more preferably between 3.1 kg I m³ and 3.9 kg I m³ of glass fibres, wherein a groove (3) extends along each of the first and second longitudinal edges, each groove having an opening width (w) measured normal to the first and second main surfaces of 2 mm + 0.3 mm, and a depth (d) measured parallel to the first and second main surfaces comprised between 25 and 60 mm, preferably between 30 and 50 mm, and wherein the board (1) has a fire classification according to IMO Res. 307(88) FTP Code 2010 of at least B15.

2. Board (1) according to claim 1 , wherein the core (1 c) comprises no calcium silicate and/or no vermiculite or not more than 3 wt.% vermiculite relative to the total weight of the core.

3. Board (1) according to claim 1 or 2, wherein beside calcium dihydrate and glass fibres, the core (1 c) comprises starch in an amount comprised between 3.15 and 6.30 kg I m³ of the core, polyvinyl alcohol (PVOH), and a foaming agent.

4. Board (1) according to anyone of the preceding claims, wherein the facer (1f) is made of a composite material comprising fibres including cellulose fibres, glass fibres.

5. Board (1) according to the preceding claim wherein the composite material comprises optionally polyester fibres, and comprises a binder resin, preferably a vinyl-acrylate copolymer or ethylene vinyl acetate.

6. Board (1) according to anyone of the preceding claims, wherein a displacement (8) of the board of length, L = 3000 mm, width, W = 1200 mm, and thickness, t = 19 mm, loaded in three point bending, is at least equal to 160 mm, preferably at least equal to 180 mm,

7. Laminate (1 L) comprising a board (1) according to anyone of the preceding claims, wherein the first and the second main surfaces are covered by a high pressure laminate (HPL) (1 hpl).

8. Laminate (1 L) according to the preceding claim, wherein the HPL (1 hpl) has a thickness (th) comprised between 0.6 and 1.2 mm.

9. Laminate (1 L) according to claim 7 or 8, wherein the HPL (1 hpl) comprises cellulose fibres impregnated in a resin.

10. Laminate (1 L) according to anyone of claims 7 to 9, wherein a displacement (8) of the laminate of length, L = 3000 mm, width, W = 1200 mm, and thickness, tL = 19 + 2 mm, loaded in three point bending, is at least equal to 120 mm, preferably at least equal to 145 mm, without failure of the gypsum board core (1 c).

11. Partition system (11) comprising first and second laminates (1) according to anyone of claims 7 to 10, which are joined to one another along a first longitudinal edge thereof by at least one spline (13) fitted in the grooves (3) of the first longitudinal edge of each of the first and second laminate (1) forming a spline joint between the two laminates (1).

12. Use of a board (1) according to anyone of claims 1 to 6, or of a laminate (1) according to anyone of claims 7 to 10, or of a partition system (11) according to claim 11 for forming panels in marine applications, including bulkheads, walls, ceilings, pieces of furniture in ships or off-shore platforms.