Zip fastener

1. A zip fastener comprising fabric fastener tapes having coil type coupling elements thereon,

wherein each fastener tape includes a coating layer of thermoplastic material on a first surface of the fastener tape, that extends continuously along the first surface, is folded back continuously at an edge of the fastener tape, and extends continuously along a portion of a second surface of the fastener tape,

wherein the coating layers on the first surfaces of the fastener tapes abut against each other at a center line of the zip fastener to form a seal,

wherein each fastener tape has a gap between the coating layer on the second surface and the coil type coupling elements attached to the second surface that exposes a portion of the second surface of the fastener tape,

wherein a barrier is disposed within each fastener tape between the coating layer on the first surface of the fastener tape and the coating layer on the second surface of the fastener tape,

wherein the coil type coupling elements are formed only on the second surface of each fastener tape,

wherein each fastener tape is configured to be sewn with a sewing thread to secure the zip fastener to an article, and

wherein the barrier is disposed at a side of the coil type coupling elements relative to the sewing thread.

2. The zip fastener according to claim 1 ,

wherein the coating layer forms a waterproof layer.

3. The zip fastener according to claim 1 , wherein a thickness of the coating layer on the first surface of the fastener tapes is thicker than the thickness of the coating layer on the second surface of the fastener tapes.

4. The zip fastener according to claim 1 , wherein the coating layer does not come into direct contact with the coil type coupling elements of the zip fastener.

5. The zip fastener according to claim 1 , wherein the fastener tapes further comprise a water resilient material.

6. The zip fastener according to claim 5 , wherein the water resilient material is adhered or woven to the fastener tapes.

7. The zip fastener according to claim 1 , wherein the barrier comprises a weld.

8. The zip fastener according to of claim 1 , wherein the fastener tapes further comprise a hydrophobic treatment.

9. The zip fastener according to claim 1 , wherein the fastener tapes are comprised of hydrophobic material.

10. The zip fastener according to claim 1 , wherein the coating layer on the first surface extends beyond an inner edge of the fastener tapes.

11. A zip fastener comprising fabric fastener tapes having coil type coupling elements thereon,

wherein a coating layer of thermoplastic material is provided on a first surface of each of the fastener tapes,

wherein the coating layer extends continuously along the first surface, extends over an edge of the fastener tape, is folded back continuously at the edge of the fastener tape, and extends continuously along a second surface of the fastener tape,

wherein the coating layers on the first surfaces of the fastener tapes abut against each other at a center line of the zip fastener to form a seal,

wherein a width dimension of the coating layer on the second surface is less than a width dimension of the coating layer on the first surface,

wherein the coil type coupling elements are formed only on the second surface of each fastener tape and do not come into direct contact with the coating layer,

wherein a barrier is disposed within each fastener tape between the coating layer on the first surface of the fastener tape and the coating layer on the second surface of the fastener tape,

wherein each fastener tape is configured to be sewn with a sewing thread to secure the zip fastener to an article, and

wherein the barrier is disposed at a side of the coil type elements relative to the sewing thread.