Ballistic resistant article comprising a self-crosslinking acrylic resin and/or a crosslinkable acrylic resin and process to manufacture said article
A ballistic resistant article is presented comprising a plurality of fibrous layers, each of said layers comprising a network of fibers, wherein the fibers have a strength of at least 800 mN/tex (1100 MPa) according to ASTM D 7269-07 and a matrix material, wherein the matrix material comprises a mixture comprising at least one self-crosslinking acrylic resin and/or at least one crosslinkable acrylic resin, and at least one tackifier. Compared with an article of the same construction but with a matrix material without tackifier the article according to the invention comprises a higher adhesion between the fibrous layers both in the unaged and aged state and a lower water pick up after water soak and the article passes the gasoline soak test. The article additionally comprising a plate of metal or ceramic exhibits minimal or even no delamination of the fibrous layers after ballistic attack, whereas an article of the same construction but with a matrix material without tackifier exhibits interior delamination of the fibrous layers.
1. A ballistic resistant article comprising a plurality of fibrous layers, each of said layers comprising a network of fibers, wherein the fibers have a strength of at least 800 mN/tex (1100 MPa) according to ASTM D 7269-07 and a matrix material, wherein the matrix material comprises a mixture comprising
at least one self-crosslinking acrylic resin and/or at least one crosslinkable acrylic resin,
and at least one tackifier providing the matrix with tack, wherein the at least one tackifier is present in the matrix material in a weight percentage with respect to the weight of the matrix material ranging from 1 wt. % to 20 wt. %.
2. The ballistic resistant article according to claim 1 , wherein the tackifier is selected from the group consisting of rosin resins or terpene resins or hydrocarbon resins.
3. The ballistic resistant article according to claim 1 , wherein the network of fibers is a unidirectional alignment of the fibers.
4. The ballistic resistant article according to claim 1 , wherein the fibers are aramid fibers.
5. The ballistic resistant article according to claim 1 , wherein the fibers have a weight w f , the matrix material has a weight w m and a weight percentage of the matrix material with respect to (w f +w m ) is from 5 wt. % to 50 wt. %.
6. The ballistic resistant article according to claim 1 , wherein the areal density of the fibers in a single fibrous layer ranges from 10 g/m 2 to 250 g/m 2 .
7. The ballistic resistant article according to claim 1 , wherein the total areal density of a single fibrous layer ranges from 11 g/m 2 to 350 g/m 2 .
8. The ballistic resistant article according to claim 1 , wherein the plurality of fibrous layers is formed into a panel and the panel is joined to a plate of metal or ceramic.
9. Ballistic resistant article according to claim 1 , wherein a scrim comprising a thermoplastic material is situated between the fibrous layers.
10. The ballistic resistant article according to claim 1 , wherein the at least one tackifier is homogenously distributed in the matrix material.
11. The ballistic resistant article according to claim 1 , wherein the at least one tackifier is present in the matrix material in the weight percentage with respect to the weight of the matrix material ranging from 1 wt. % to 20 wt. % to reduce water pickup in comparison to a ballistic resistant article of the same construction but without the tackifier.
12. The ballistic resistant article according to claim 1 , wherein the at least one tackifier is present in the matrix material in the weight percentage with respect to the weight of the matrix material ranging from 1 wt. % to 20 wt. % to reduce delamination of the plurality of fibrous layers upon ballisitic attack in comparison to a ballistic resistant article of the same construction but without the tackifier.
13. A process to manufacture a ballistic resistant article comprising the steps:
(1) Manufacture of a single unidirectional fibrous layer comprising a matrix material, which comprises a mixture comprising
at least one self-crosslinking acrylic resin and/or at least one crosslinkable acrylic resin, and
at least one tackifier providing the matrix with tack, wherein the at least one tackifier is present in the matrix material in a weight percentage with respect to the weight of the matrix material ranging from 1 wt. % to 20 wt. %,
(2) manufacture of an adherent cross-ply from at least two unidirectional single fibrous layers resulting from step (1),
(3) manufacture of a consolidated panel from a number of adherent cross-plies resulting from step (2), and optionally
(4) joining of the consolidated panel resulting from step (3) to a plate of metal or ceramic to yield a hard-ballistic resistant article.
14. The process according to claim 13 , wherein a cross-linking reaction of the at least one self-crosslinking acrylic resin and/or of the at least one crosslinkable acrylic resin is comprised in at least one of the steps (1), (2) and (3).