Ballistic resistant articles comprising elongate bodies
A ballistic-resistant molded article comprising a compressed stack of sheets comprising reinforcing elongate bodies and an organic matrix material, the direction of the elongate bodies within the compressed stack being not unidirectionally, wherein the elongate bodies are tapes with a width of at least 2 mm and a thickness to width ratio of at least 10:1 with the stack comprising 0.2-8 wt. % of an organic matrix material.
1. A ballistic-resistant moulded article comprising a compressed stack of sheets comprising reinforcing elongate bodies and an organic matrix material, a direction of the elongate bodies within the compressed stack being not unidirectional, wherein
the elongate bodies are tapes with a width of at least 2 mm and a width to thickness ratio of at least 10:1 with the stack comprising 0.2-8 wt. % of the organic matrix material, and
the tapes are polyethylene tapes having a 200/110 uniplanar orientation parameter of at least 3, the 200/110 planar orientation parameter being defined as a ratio between the 200 peak and the 110 peak areas in an X-ray diffraction (XRD) pattern of a sample of the tape as determined in reflection geometry.
2. The ballistic-resistant moulded article according to claim 1 , wherein the width to thickness ratio of the tapes is more than 20:1.
3. The ballistic-resistant moulded article according to claim 1 , wherein the width of the tape is at least 10 mm.
4. The ballistic-resistant moulded article according to claim 1 , wherein the tapes in the sheets are unidirectionally oriented, and the direction of the tapes in a sheet is rotated with respect to the direction of the tapes in an adjacent sheet.
5. The ballistic-resistant moulded article according to claim 1 , wherein a sheet comprises reinforcing tapes and 0.2-8 wt. % of organic matrix material.
6. The ballistic-resistant moulded article according to claim 1 , wherein at least some of the sheets are substantially free from matrix material and matrix material is present between the sheets.
7. The ballistic-resistant moulded article according to claim 1 , wherein the tapes have a tensile strength of at least 1.0 GPa, a tensile modulus of at least 40 GPa, and a tensile energy-to-break of at least 15 J/g.
8. The ballistic-resistant moulded article according to claim 1 , wherein the tapes are of ultra-high molecular weight polyethylene (UHMWPE) with a weight average molecular weight of at least 500 000 g/mol.
9. The ballistic-resistant moulded article according to claim 1 , wherein at least some of the polyethylene tapes have a weight average molecular weight of at least 100 000 g/mol and a Mw/Mn ratio of at most 6.
10. The ballistic-resistant moulded article according to claim 9 , wherein the polyethylene tapes have a weight average molecular weight of at least 300 000 g/mol, and a Mw/Mn ratio of at most 5.
11. A consolidated sheet package suitable for use in the manufacture of the ballistic-resistant moulded article of claim 1 , the consolidated sheet package comprising 2-8 sheets comprising reinforcing tapes, and an organic matrix material, a direction of the tapes within the sheet package being not unidirectional, and the sheet package comprising 0.2-8 wt. % of the organic matrix material, wherein
the tapes are polyethylene tapes having a 200/110 uniplanar orientation parameter of at least 3, the 200/110 uniplanar orientation parameter being defined as a ratio between the 200 peak and the 110 peak areas in an X-ray diffraction (XRD) pattern of a sample of the tape as determined in reflection geometry.
12. A method for manufacturing the ballistic-resistant moulded article according to claim 1 , comprising:
providing sheets comprising reinforcing tapes;
stacking the sheets in such a manner that a direction of the tapes within the stack is not unidirectional; and
compressing the stack under a pressure of at least 0.5 MPa, wherein
the compressed stack comprises 0.2-8 wt. % of an organic matrix material provided within the sheets, between the sheets, or both within and between the sheets, and
the tapes are polyethylene tapes having a 200/110 uniplanar orientation parameter of at least 3, the 200/110 uniplanar orientation parameter being defined as a ratio between the 200 peak and the 110 peak areas in an X-ray diffraction (XRD) pattern of a sample of the tape as determined in reflection geometry.
13. The method according to claim 12 , wherein the sheets are provided by providing a layer of tapes and causing the tapes to adhere.
14. The method according to claim 13 , wherein tapes are caused to adhere via compression.