Transparent antiballistic article and method for its preparation

Patent metadata

Field	Value
Publication number	US-9821536-B2
Application number	US-201314438036-A
Country	US
Kind code	B2
Filing date	Oct 29, 2013
Priority date	Oct 30, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

This invention relates to a process for the preparation of an antiballistic article, the method comprising: a) Providing a transparent uniaxially stretched polymeric film with at least one layer I comprising a semi-crystalline thermoplastic polymer A and at least one layer II comprising an amorphous or semi-crystalline thermoplastic polymer B, of which polymer B has a glass transition temperature less than the melting temperature of polymer A if polymer B is amorphous or of which polymer B has a melting temperature less than the melting temperature of polymer A if polymer B is semi-crystalline; b) Stacking at least two of the uniaxially stretched polymeric films of a) at an angle a of between 45° and 135°, such that the films are in contact with each subsequent film through at least one layer II, to form an assembly; c) Compressing the thus formed assembly at a temperature above the glass transition temperature of polymer B if polymer B is amorphous, or above the melting temperature of polymer B if polymer B is semi-crystalline, and below the melting temperature of polymer A, to obtain an haze of at most 50% and having an energy absorption for 17 grain FSP according to the STANAG 2920 standard of at least 12 J/(kg/m 2 ). The invention also relates to antiballistic articles.

First claim

The invention claimed is:

1. A method for the preparation of an antiballistic article, the method comprising the steps of:
(a) providing a transparent uniaxially stretched polymeric film with at least one layer I comprising a semi-crystalline thermoplastic polymer A and at least one layer II comprising an amorphous or semi-crystalline thermoplastic polymer B, wherein the polymer B has a glass transition temperature which is at least 15° C. less than a melting temperature of the polymer A if the polymer B is amorphous or wherein the polymer B has a melting temperature which is at least 15° C. less than the melting temperature of the polymer A if the polymer B is semi-crystalline;
(b) stacking at least two of the uniaxially stretched polymeric films of step (a) at an angle α of between 45° and 135° , such that the films are in contact with each subsequent film through at least one layer II, to form an assembly;
(c) compressing the thus formed assembly of step (b) at a temperature above the glass transition temperature of polymer B if polymer B is amorphous, or above the melting temperature of polymer B if polymer B is semi-crystalline, and below the melting temperature of polymer A, to obtain a haze of at most 50% and having an energy absorption for 17 grain FSP according to the STANAG 2920 standard of at least 12 J/(kg/m 2 ).

2. The method according to claim 1 , wherein the haze is at most 10%.

3. The method according to claim 1 , wherein the angle α is between 80° and 100° .

4. The method according to claim 1 , wherein the uniaxially stretched polymeric film in step (a) has a total of 3 layers, wherein two layers II are opposite of one layer I.

5. The method according to claim 1 , wherein step (b) includes contacting the films with each subsequent film through two layers II.

6. The method according to claim 4 , wherein the polymer B in the two layers II is the same.

7. The method according to claim 1 , wherein the polymer A is selected from the group consisting of polyamides, co-polyamides, polyesters, and polypropylene.

8. The method according to claim 1 , wherein the polymer A is selected from the group consisting of aliphatic polyamides, semi-aromatic polyamides, and polyamide blends.

9. The method according to claim 1 , wherein the polymer B is a co-polyamide.

10. The method according to claim 1 , wherein the polymer A is polyamide-6/6T and the polymer B is a polyamide-6/66.

11. The method according to claim 1 , wherein step c) is performed by compressing the assembly at a pressure less than 100 Bar.

12. The method according to claim 1 , wherein step (c) is performed by compressing the assembly at a pressure less than 50 Bar.

13. The method according to claim 1 , wherein the uniaxially stretched polymeric film provided in step (a) is prepared by a multilayer film cast extrusion process.

14. The method according to claim 1 , wherein the polymer B has a glass transition temperature which is at least 20° C. less that the melting temperature of the polymer A if the polymer B is amorphous or wherein the polymer B has a melting temperature which is at least 20° C. less than the melting temperature of the polymer A if the polymer B is semi-crystalline.

15. The method according to claim 1 , wherein the polymer B has a glass transition temperature which is at least 30° C. less that the melting temperature of the polymer A if the polymer B is amorphous or wherein the polymer B has a melting temperature which is at least 30° C. less than the melting temperature of the polymer A if the polymer B is semi-crystalline.

16. An antiballistic article obtained by the method of claim 1 having a haze of at most 10% and having an energy absorption for 17 grain FSP according to the STANAG 2920 standard of at least 12 J/(kg/m 2 ).

Assignees

• Dsm Ip Assets Bv

Inventors

• Dorschu Marko
• Stroeks Alexander Antonius Marie
• Chen Hao

Classifications

• B32B2307/516

  mono-axially · CPC title

• B32B2307/40

  having particular optical properties · CPC title

• B32B2307/54

  Yield strength; Tensile strength · CPC title

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title

• B32B27/34

  comprising polyamides · CPC title