IMPACT RESISTANT COMPOSITE MATERIAL
The invention relates to a preformed sheet, comprising a network of polyethylene fibers having a tensile strength of at least 1.5 GPa, impregnated with at least 10% of a plastic wherein the plastic material is an acrylic based thermoplastic material with a glass transition temperature of at least 25° C. The invention further relates to an assembly of at least two preformed sheets and to a ballistic resistant article comprising at least one assembly.
1 . Preformed sheet, comprising a network of polyethylene fibers having a tensile strength of at least 1.5 GPa, impregnated with at least 10% of a plastic material characterized in that the plastic material is an acrylic based thermoplastic material with a glass transition temperature of at least 25° C.
2 . Preformed sheet according to claim 1 , wherein the network of fibers comprises a fabric.
3 . Preformed sheet according to claim 1 wherein the network of fibers comprises unidirectionally aligned fibers.
4 . Preformed sheet according to claim 1 , wherein the fibers are UHMWPE fibers.
5 . Preformed sheet according to claim 1 , wherein the preformed sheet comprises a separating film on at least one of its outer surfaces.
6 . Preformed sheet according to claim 5 , wherein the separating film is a biaxially stretched polyolefin film.
7 . Assembly of at least two preformed sheets according to claim 1 , which sheets are substantially not linked to one another.
8 . Ballistic resistant article comprising at least one assembly according to claim 7 .
9 . Ballistic resistant article comprising a plurality of preformed sheets according to claim 2 having an Eabs of more than 180 J/kg/m 2 for 9 mm*19 Natoball DM11 A1B2 bullet.
10 . Ballistic resistant article according to claim 9 , further comprising at least two networks of unidirectionally aligned fibers with optionally a matrix.
11 . Ballistic resistant article according to claim 10 , wherein the matrix for the unidirectional aligned fibers comprises a modified polyolefin, a SIS, or a SEBS.
12 . Ballistic resistant article according to claim 10 , wherein the matrix for the unidirectional aligned fibers comprises a polyurethane.
13 . Ballistic resistant article according to claim 10 , wherein the matrix for the unidirectional aligned fibers is an acrylic based thermoplastic material with a glass transition temperature of at least 25° C.
14 . Use of an acrylic based thermoplastic material with a glass transition temperature of at least 25° C. in the manufacture of ballistic resistant composites.
15 . Use of an acrylic based thermoplastic material with a glass transition temperature of at least 25° C. in the manufacture of ballistic resistant composites comprising polyethylene fibers.