This invention relates to a mineral wool insulation panel, in particular for use in fire rated doors.

EP1533462A relates to a construction for a fire rated door and discloses the use of a plurality of mineral wool insulation panels within the door cavity, each mineral wool panel having a different density and/or quantity of fire retardants. This is intended to optimise the insulation to correspond to the varying temperature stresses over the height of the door. A disadvantage with this arrangement is the need to supply and assemble different individual mineral wool panels. One aim of the present invention is to facilitate the supply and assembly of mineral wool panels, particularly for fire rated doors. Another aim is to alleviate the risk of weak points of prior arrangements of insulations panels for fire rated doors whilst optimising material useage.

According to one aspect, the present invention provides a mineral wool insulation panel as defined in claim 1 . Other aspects are defined in other dependent claims whilst the dependent claims define preferred and/or alternative embodiments.

The provision of a single piece mineral wool insulation panel having a height of at least 160 cm and a width of at least 60cm allows the panel to be used without requiring additional panels to fill the cavity of a fire rated door. Handling and assembling a single panel is easier and more efficient than dealing with multiple different panels. In addition, the provision of a single or unitary panel having dimensions that can fill the entire cavity of a door avoids the risk of a point of weakness or a thermal bridge in the insulation that would occur at the abutments of separate but adjoining panels. The panel may be substantially rectangular; it may be provided with preformed cuts and/or cut-outs to facilitate its assembly in a door cavity.

The dimensions of the panel may be:

• height≥ 160 cm, optionally≥ 180 cm or≥ 200 cm and/or < 260 cm, optionally < 240 cm or < 230 cm;

· width≥ 60 cm, optionally≥ 70 cm or≥ 80 cm and/or < 150 cm, optionally <

120 cm or < 100 cm; • thickness preferably≥ 1 ,5 cm, optionally≥ 3 cm or≥ 4 cm and/or preferably < 12 cm, optionally < 10 cm or < 8 cm

The thermal stresses to which a door is subjected during a fire or fire test are not constant over the height of the door. The configuration of lower, central and upper bands in the insulation panel allows the upper and/or lower bands to be arranged with a desired higher density of mineral wool insulation for achieving a desired fire resistance and/or thermal performance without the use of the same high density at the central band. This reduces the total weight and thus cost of the mineral wool panel compared to a single panel having a homogeneous density of the density of the upper and/or lower bands. In one preferred embodiment, the density at the upper and lower bands is substantially the same and/or the mineral wool panel is substantially symmetrical about its central horizontal axis; this allows the panel to be used in a door cavity either way up and thus facilitates assembly. The most critical portion of a door for its fire resistance or performance is generally a band across the width of the door at or towards its top edge and/or a band across the width of the door at or towards its bottom edge. The panel according to the present invention thus provides for a high density of mineral wool insulation to be provided at these areas whilst using a lower density of mineral wool at a central band across the width of the door at which such a high density would be unnecessary. In another preferred embodiment, the density at the lower band is less than the density at the central band, and the density at the central band is less than the density at the upper band; this provides a useful optimisation of the quantity of mineral wool insulation use in the panel whilst providing for a desired density of mineral wool insulation at the upper band, for example to achieve a desired fire class. Each of the upper and lower bands may have a height≥ 5 cm, preferably≥ 10 cm, more preferably≥ 15 cm and/or < 60 cm, preferably < 40 cm, more preferably < 30 cm. One edge of each of the upper and/or lower bands may be situated respectively at the upper and lower edge of the panel. The density of mineral wool over each or any of the upper, central and lower bands need not be homogeneous. Indeed, transition in density between the upper and/or lower bands and the central band is preferably gradual as opposed to being a step change in density.

The density at each of the upper and lower bands may be≥ 100 kg/m ³ , preferably≥ 120 kg/m ³ , more preferably≥ 140 kg/m ³ and/or < 220 kg/m ³ , preferably < 250 kg/m ³ , more preferably < 300 kg/m ³ . The density at the central band may be≥ 60 kg/m ³ , preferably≥ 80 kg/m ³ , more preferably≥ 100 kg/m ³ and/or < 180 kg/m ³ , preferably < 210 kg/m ³ , more preferably < 250 kg/m ³ . Since the density throughout each band need not be homogeneous, the density for a band may be determined by taking three samples each having dimensions of about 10 cm x 10 cm at locations along a single line substantially parallel to the top or bottom edge of the panel across the width of the panel and determining the average density of these three samples.

The density at the upper band and/or central band and/or lower band may be substantially constant across the entire width of the panel at that band. For example, the density at such band(s) across the entire width of the panel may be within the range of ± 10 kg/m ³ or ± 5 kg/m ³ with respect to the average density at the band in question, such average density and variation in density at a band being determined by taking a representative number of samples each having dimensions of about 10 cm x 10 cm at locations along a single line within the band substantially parallel to the top or bottom edge of the panel across the width of the panel. The density of the mineral wool insulation at each of the upper and lower bands may be greater than the density of the mineral wool insulation at the central band by at least 8 %, more preferably by at least 12 % and even more preferably by at least 15 %.

One position at a fire rated door which may be considered critical in terms of its fire performance is the position towards a corner of the door spaced 10 cm from each of the adjacent edges at that corner. Consequently, it is preferred that each such position of the mineral wool insulation panel is situated within one of the upper or lower bands.

The mineral wool is preferably stone wool; alternatively it may be glass wool. Where the mineral wool comprises a binder, this may be present at a quantity of≥ 0,5 wt % preferably≥ 0,8 wt %, and/or < 4 wt %, preferably < 3 wt % expressed a % weight with respect to the mineral wool including the binder and measured, for example, by loss on ignition. Such a binder is preferably a thermally cured organic binder, for example a phenol formaldehyde binder, a urea formaldehyde binder or a binder based on carbohydrates, applied to the mineral fibre between their formation and their collection together as a primary mat. In some embodiments the panel is free of binder or substantially free of binder. The mineral wool may account for at least 85%, at least 90%, at least 94%, at least 96% or at least 98% by weight of the mineral wool insulation panel. The panel is particularly suited for use in doors, particularly in fire rated doors and even more particularly in doors meeting a Ei 30, Ei40, Ei 60, Ei90 or Ei120 fire class. The doors may comprise a peripheral skin, preferably comprising sheet metal, notably steel, which define an internal door cavity in which the mineral wool panel is arranged.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings of which:

Fig 1 is a schematic plan view of a mineral wool insulation panel;

Fig 2 is a schematic side view of the panel of Fig 1 ;

Fig 3 is a schematic perspective representation of part of a production process by which such a panel may be manufactured;

Fig 4 and Fig 5, Fig 6 and Fig 7, and Fig 8 and Fig 9 are pairs of view similar to Fig 1 and Fig 2, each pair of views illustrating an alternative mineral wool insulation panel.

The single piece stone wool insulation panel 10 illustrated in Figs 1 and 2 has a height h of about 200 cm, a width w of about 80 cm and a thickness t of about 6cm. It is substantially rectangular having a top edge 1 1 , bottom edge 12, and first 13 and second 14 side edges.

An upper band 21 , a central band 23 and a lower band 22 each extend across the width of the panel 10. In the embodiment illustrated in Fig 1 and Fig 2, the upper 21 and lower bands 22 each have a higher density of mineral wool than the central band 23. The density of the mineral wool insulation in the height direction h is not homogeneous by varies gradually and transition zones 24, 25 also of gradually varying density separate each of the upper and lower bands 21 ,22 from the central band 23. A representative density of each band may be taken as the average density along imaginary upper 31 , lower 32 and central 33 sample lines situated respectively within each band and running across the width w of the panel parallel to the top and bottom edges 1 1 ,12, the central sample line preferably being situated mid-way between the top edge 1 1 and the bottom edge 12 of the panel, the upper sample line 31 preferably being situated at a distance of about 15 cm from the top edge 1 1 and the lower sample line 32 preferably being situated at a distance of about 15 cm from the bottom edge 12.

Each of four near corner positions 41 , 42, 43, 44, each of which is situated proximate a corner of the panel 10 at a distance of 10 cm from each edge of the mineral wool insulation panel at that corner, is situated within one of the upper or lower bands 21 , 22.

Fig 3 illustrates part of an apparatus which may be used to manufacture a mineral wool panel 10. Mineral wool fibres, to which a thermally curable binder has preferably been applied, are transferred in the form of a primary mat 61 having a substantially homogeneous weight per unit area across its width w-i from a collection belt 62 to a primary mat conveyor 63 advancing in a first direction 64. A swinging pendulum mechanism 66 is used to transfer the primary mat 61 to a secondary mat conveyer 68 advancing in a direction 69 substantially perpendicular to the primary mat conveyer 63 so as to form a secondary mat 70 by reciprocal folding of the primary mat 61 . The speed of the pendulum towards at least one of its apexes of its movement is arranged to be different, for example lower, than the speed of the pendulum at its central position; in this way, with the secondary mat conveyer 68 advancing at a substantially constant speed, a different, for example, greater quantity (weight per unit area) of the primary mat 61 is deposited at one or both side edges 71 , 72 at the extremities of the width w ₂ of the secondary mat 70 than is deposited at the central position 73 across the width w ₂ of the secondary mat 70.

In a subsequent step (not illustrated) the secondary mat is compressed, its binder (when present) is cured in a curing oven ant its edges 71 , 72 are preferably trimmed. Advantageously, the width w ₂ of the secondary mat 70 is arranged to be substantially the same as the desired height h of the mineral wool insulation panel 10 so that after any edge trimming of the mat, the mat is cut across its width w ₂ to form the mineral wool insulation panel 10, the width w ₂ of the mat thus becoming the height h of the panel. In this way, there is little or no waste generated from cutting of the mat to form the panels 10.

The following tables sets out a number of different embodiments: Example 1 (illustrated in Figs 1 and 2)

Example 2 (illustrated in Figs 4 and 5) Example 3 (illustrated in Figs 6 and 7)

Example 4 (illustrated in Figs 8 and 9)

Density Comments

Mineral wool density at 120 kg/m ³ to 170 kg/m ³ ,

upper band preferably about 140

kg/m ³ to 150 kg/m ³ ± 10

kg/m ³

Mineral wool density at 160 kg/m ³ to 200 kg/m ³ , Density at central band central band preferably about 180 higher than density at each kg/m ³ ± 10 kg/m ³ of the upper and lower bands

Mineral wool density at 120 kg/m ³ to 170 kg/m ³ , Density at lower band lower band preferably about 140 preferably substantially kg/m ³ to 150 kg/m ³ ± 10 similar (e.g. ± 10 kg/m ³ ) kg/m ³ with respect to density at upper band