Ballistic-resistant molded article

1. A process for producing a ballistic-resistant molded article, wherein the molded article comprises:

i) a plurality of layers of unidirectionally aligned fused polyolefin fibers, which layers are substantially absent a bonding matrix; and

ii) a plurality of layers of adhesive between adjacent layers of the unidirectionally aligned fused fibers, and wherein

the process comprises:

a) providing a plurality of precursor sheets, each of said precursor sheets comprising:

i) at least one layer of unidirectionally aligned fused polyolefin fibers, wherein the at least one layer is substantially absent of a bonding matrix, and

ii) at least one layer of adhesive;

b) stacking the precursor sheets to form a stack, wherein the total amount of the adhesive in the stack is from 5.0 to 12.0 wt. % based on the total weight of the stack;

c) pressing the stack produced in step b) at a temperature of from 1 to 30° C. below the melting point of the polyolefin fibers and at a pressure of at least 8 MPa; and

d) cooling the pressed stack produced in step c) to at least 50° C. below the melting point of the polyolefin fibers while maintaining pressure.

2. The process according to claim 1 , wherein the pressure of step c) is at least 10 MPa.

3. The process according to claim 1 , wherein the total amount of the adhesive present is from 6.0 to 11.0 wt. % based on the total weight of the stack.

4. The process according to claim 1 , wherein step b) comprises orienting each layer of the unidirectionally aligned fused polyolefin fibers which layer in which a bonding matrix is substantially absent at an angle of from 45° to 135° with respect to an orientation of the unidirectionally aligned fused polyolefin fibers of an adjacent layer of polyolefin fibers in which a bonding matrix is substantially absent.

5. The process according to claim 1 , wherein step b) comprises separating each layer of the unidirectionally aligned fused polyolefin fibers in which a bonding matrix is substantially absent from an adjacent layer of the unidirectionally aligned fused polyolefin fibers in which a bonding matrix is absent by a layer of adhesive.

6. The process according to claim 1 , further comprising, before step a), step a′) producing a precursor sheet which comprises:

i) at least one layer of unidirectionally aligned fused polyolefin fibers in which a bonding matrix is substantially absent, and

ii) at least one layer of adhesive;

by applying a layer of adhesive to a layer of unidirectionally aligned fused polyolefin fibers in which a bonding matrix is substantially absent.

7. The process according to claim 6 , wherein step a′) comprising applying from 5.0 to 12.0 wt % adhesive to the layer of the unidirectionally aligned fused polyolefin fibers in which a bonding matrix is substantially absent a bonding matrix, based on the total weight of the layer and the adhesive.

8. The process according to claim 7 , wherein step a′) further comprises consolidating two layers of the unidirectionally aligned fused polyolefin fibers in which a bonding matrix is substantially absent, and a layer of adhesive, wherein the layers of unidirectionally aligned fused polyolefin fibers are separated by the layer of adhesive.

9. The process according to claim 8 , wherein step a′) comprises orienting the two layers of the unidirectionally aligned fused polyolefin fiber in which a bonding matrix is substantially absent at from 45° to 135° relative to each other.