COMPOSITE MATERIALS AND USES THEREOF

Abstract

The present invention relates to composite materials and the use thereof as energy resistant, for example blast-resistant, materials. Preferred aspects of the invention relate to layered composite panels comprising solid foam materials which have both a blast attenuation function and an anti-ballistic function. In further aspects, the invention provides novel composite panels which are suitable for use as blast resistant and/or anti-ballistic materials. In some examples described, the layered composite panel comprises a polymeric material (10) bonded to a first solid open-cell foam panel (12), and a cured polymeric material (14) penetrates a surface of the first solid open-cell foam panel (12).

Claims

1-77. (canceled)

78. A method of providing a blast-resistant shield, wherein the layered composite panel comprises: (i) a first surface layer of a sheet form polymeric material; and (ii) a core comprising or consisting of a first solid, open-cell foam panel, wherein the sheet form polymeric material comprises a cured polymeric material which penetrates a surface of the open-cell foam panel forming a bond between the first surface layer and the core and the open-cell foam panel comprises a phenolic resin foam.

79. The method according to claim 78, wherein the layered composite panel comprises a core comprising or consisting of the first solid, open-cell foam panel and a second solid foam panel, wherein the foam panels are bonded together by an adhesive or other bonding agent so as to form a monolithic layered structure.

80. The method according to claim 79, wherein the second solid, open-cell foam is an open-cell phenolic resin foam.

81. The method according to claim 78, wherein the first solid, open-cell foam panel is non-elastically deformable; or wherein the first solid, open-cell foam panel is frangible; or wherein the first solid, open-cell foam panel is progressively deformable.

82. The method of claim 78, wherein the first solid, open-cell foam panel includes a finely-divided particulate reinforcing material selected from: clays, clay minerals, talc, vermiculite, metal oxides, refractories, solid or hollow glass microspheres, fly ash, coal dust, wood flour, grain flour, nut shell flour, silica, mineral fibers, chopped fibers, finely chopped natural or synthetic fibers, ground plastics and resins, pigments, and starches.

83. The method of claim 78, wherein the first solid, open-cell foam panel further comprises chips of stone, ceramic, glass or other aggregate materials embedded in the open-cell foam matrix.

84. The method of claim 78, wherein the first solid open-cell foam panel has a density in the range of 100 to 500 kg m.sup.3 exclusive of any aggregate chips that may be embedded in the foam.

85. The method of claim 78, wherein the first solid open-cell foam panel comprises a foam having an average cell diameter in the range of about 0.5 mm to 5 mm.

86. The method of claim 79, wherein the adhesive or bonding agent used to bond the first and second foam layers comprises or consists of one or more elastomers selected from: natural rubber, synthetic polyisoprene, butyl rubber, halogenated butyl rubber, polybutadiene, styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, silicone rubber, and halogenated silicone rubber.

87. The method of claim 86, wherein the elastomer penetrates the first and/or second solid, open-cell foam panel to a depth which is at least equivalent to the average cell diameter of the foam.

88. The method of claim 86, wherein the elastomer penetrates the first and/or second solid, open-cell foam panel to a depth of at least 0.5 mm.

89. The method of claim 78, wherein the sheet-form polymeric material comprises a matrix comprising or consisting of a thermosetting polymer resin selected from: polyester resins, vinyl ester resins, epoxy resins, phenolic resins, bismaleimide resins or polyimide resins.

90. The method of claim 78, wherein the sheet-form polymeric material comprises one or more of carbon fibers, glass fibers, aramid fibers and/or polyethylene fibers.

91. The method of claim 78, wherein the sheet-form polymeric material has a thickness in the range of from 0.5 to 25 mm.

92. The method of claim 78, wherein a portion of the sheet-form polymeric material penetrates the first solid, open-cell foam panel to a depth which is at least equivalent to the average cell diameter of the foam; or wherein a portion of the sheet-form polymeric material penetrates the first solid, open-cell foam panel to a depth of at least 0.5 mm.

93. The method of claim 78, wherein the core comprises one or more further core layers.

94. The method of claim 93, wherein the core comprises one or more reinforcing layers; or wherein the core comprises one or more further layers of sheet form polymeric material.

95. The method of claim 78, wherein the layered composite panel further comprises (iii) a second surface layer of a sheet form polymeric material, and wherein the core is disposed between the first and second surface layers of sheet-form polymeric material.

96. The method of claim 78, wherein the layered composite panel has a profiled surface.

97. The method of claim 78, wherein the core has a thickness in the range of from 20 to 500 mm; or wherein the layered composite panel has a thickness in the range of from 21 to 550 mm.

Description

[0134] Preferred features of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which:

[0135] FIGS. 1 to 5 show a schematic cross-sectional view of various embodiments of the layered composite panels of the invention (not drawn to scale).

[0136] FIG. 6A shows schematically in cross-sectional exploded view the moulding of a layered composite panel of the invention having a profiled surface (not drawn to scale).

[0137] FIG. 6B shows schematically in cross-sectional view the moulding of a layered composite panel of the invention having a profiled surface (not drawn to scale).

[0138] FIG. 6C shows schematically in cross-sectional view a moulded layered composite panel of the invention having a profiled surface (not drawn to scale).

[0139] FIG. 7A shows schematically in cross-sectional view a layered composite panel of the invention before impact (not drawn to scale).

[0140] FIG. 7B shows schematically in cross-sectional view the effect of an impact on a layered composite panel of the invention (not drawn to scale).

[0141] In FIG. 1, a layered composite panel is shown having a first surface layer of a sheet form polymeric material (10) bonded to a first solid open-cell foam panel (12), wherein a cured polymeric material (14) penetrates a surface of the first solid open-cell foam panel (12).

[0142] In FIG. 2, a second surface layer of a sheet form polymeric material (16) is also bonded to the first solid open-cell foam panel. Again, a cured polymeric material (18) penetrates a surface of the first solid open-cell foam panel (12). In FIG. 3, the core comprises first and second solid open-cell foam panels (12, 20) respectively bonded to first and second surface layers of sheet form polymeric material (10, 16). A cured polymeric material (14, 18) penetrates a surface of each of the first and second solid open-cell foam panels (12, 20), and an elastomeric adhesive (22) bonds the first and second solid open-cell foam panels together. As shown, the elastomeric adhesive penetrates a portion of each of the first and second solid open-cell foam panels. In FIG. 4, a third solid open-cell foam panel (26) is provided between the first and second solid open-cell foam panels (12, 20). An elastomeric adhesive (22, 24) bonds the first, second and third solid open-cell foam panels together, and penetrates a portion of each of the foam panels. As shown, the third solid open-cell foam panel comprises chips (28) of stone, ceramic, glass or other aggregate materials embedded in the solid open-cell foam matrix.

[0143] In FIG. 5, a reinforcing panel (30), such as a glass-reinforced plastics material, is provided between the first and second solid open-cell foam panels (12, 20). As shown in FIGS. 6A to 6C, a profiled surface of the layered composite panels of the invention may be formed by a moulding process.

[0144] Thus, a layer of sheet form polymeric material (10), preferably SMC, is applied to the upper surface of a mould (32). The sheet-form polymeric material (10) is preferably sized so as to extend across the whole of the mould surface. Onto the sheet form polymeric material (10) is applied a solid open-cell foam panel (12). The foam used is advantageously: [0145] structural and has load bearing properties; [0146] frangible and can be formed under pressure; [0147] inelastic, such that it substantially retains its pressed form; and [0148] open cell such that gases may escape from the foam matrix during pressing and such that curable materials in the sheet form polymeric material can migrate into the open cells of the foam so as to form a strong bond between the sheet form polymeric material and the foam.

[0149] Downward pressure is applied to the components as shown in FIG. 6B using a pressure plate (34). Preferably, the layers are also heated. The foam layer (12) is pressed toward the lower mould surface (32), crushing the foam and moulding the lower surface of the foam (12) to the shape of the mould surface (32). The sheet form polymeric material (10) Is also pressed between the mould surface (32) and the foam layer (12). Preferably, the sheet form polymeric material is heated so as to cure the polymeric material.

[0150] Air and other gases trapped between the sheet form polymeric material (10) and the foam layer (12) pass through the open cell structure of the foam. The components are held in the mould with the application of pressure and heat for a sufficient time for the formation of a bond between the layers, e.g. the curing time of the SMC. The resulting product is then removed from the mould as shown in FIG. 6C, and may subsequently be bonded to a first insulating layer as described above.

[0151] In FIGS. 7A and 7B, a layered composite panel is shown having two first solid open-cell foam panels (12) sandwiching a lower density second solid open-cell foam panel (20).

[0152] An energy wave (36) is shown approaching the composite panel in FIG. 7A, and impacting on the composite panel in FIG. 7B. As shown in FIG. 7B, the impact compresses the lower density second solid open-cell foam panel. The first solid open-cell foam panel remains intact.

EXAMPLES

Example 1

[0153] A blast resistant panel was constructed from a core consisting of a single solid open-cell phenolic resin foam panel (82 mm thickness), a first surface layer of SMC (1.5 mm) and a second surface layer of SMC (1.5 mm). A layer of orientated glass fibre fabric (1 mm) was provided between the phenolic resin foam panel and the first surface layer of SMC. The constituent layers of the blast-resistant panel were assembled and heated and pressed to cure the SMC, such that a curable material from the first surface layer of SMC penetrated the orientated glass fibre fabric and the surface of the phenolic resin foam, and a curable material from the second surface layer of SMC penetrated the opposite surface of the phenolic resin foam panel. The resulting panel had a thickness of 85 mm. A layer of Kevlar? webbing (a poly-aramid webbing) was fixed to the second surface layer of SMC.

[0154] Four of these panels, measuring 2.0 m in height and 0.80 m in width were assembled adjacent to one another in a steel frame using expansion clips, so as to form a wall of approximately 2.4 m in height and 4.0 m in width.

[0155] An explosive charge (1800 kg of ammonium nitrate-fuel oil) was detonated at a distance of 70 m from the wall, to produce a shock wave having an impulse of 150 psi.Math.ms.sup.?1.

[0156] A pressure monitor positioned behind the wall during the detonation recorded no change in pressure due to the explosive blast. In addition, no damage to the panels was observed.

Example 2

[0157] A blast resistant panel was constructed from a core comprising a first solid open-cell phenolic resin foam panel (40 mm thickness) bonded to a reinforcing layer of glass fibre reinforced plastic (13 mm) which was itself bonded to a second solid open-cell phenolic resin foam panel (40 mm thickness). Thus, the core comprised a glass fibre reinforced plastic material bonded between two phenolic resin foam panels. A first surface layer of SMC (1.5 mm) and a second surface layer of SMC (1.5 mm) were bonded to the first and second solid open-cell foam panels, respectively. A layer of orientated glass fibre fabric (1 mm) was provided between the first solid open-cell phenolic resin foam panel and the first surface layer of SMC. The constituent layers of the blast-resistant panel were assembled, heated and pressed to cure the SMC, such that a curable material from the first surface layer of SMC penetrated the orientated glass fibre fabric and the surface of the first solid open-cell phenolic resin foam panel, and a curable material from the second surface layer of SMC penetrated the opposite surface of the phenolic resin foam panel. The resulting panel had a thickness of 85 mm. A layer of Kevlar? webbing (a poly-aramid webbing) was fixed to the second surface layer of SMC.

[0158] As above, four of these panels, measuring 2.0 m in height and 0.80 m in width were assembled adjacent to one another in a steel frame using expansion clips, so as to form a wall of approximately 2.4 m in height and 4.0 m in width.

[0159] An explosive charge (1800 kg of ammonium nitrate-fuel oil) was detonated at a distance of 70 m from the wall, to produce a shock wave having an impulse of 150 psi.Math.ms.sup.?1.

[0160] A pressure monitor positioned behind the wall during the detonation recorded no change in pressure due to the explosive blast. In addition, no damage to the panels was observed.

Comparative Example 3

[0161] A wall measuring approximately 2.4 m in height, 4.0 m in width and 0.20 m in depth was constructed from concrete blocks of approximate dimensions 15 cm in height, 30 cm in length and 20 cm in depth and standard building mortar.

[0162] An explosive charge (1800 kg of ammonium nitrate-fuel oil) was detonated at a distance of 70 m from the wall, to produce a shock wave having an impulse of 150 psi.Math.ms.sup.?1. The wall was totally demolished, with none of the mortar joints remaining intact and with a majority of the concrete blocks fragmenting.