Pneumatic Fenders Properties

Material Properties of Pneumatic Fenders

1. Rubber

The selection of our rubber is strictly accordance with the requirement of ISO 17357:2002.

Outer and inner rubber material requirements
Test item	Test method	Required valuve
Test item	Test method	Out rubber	Inner rubber
1. Before ageing	---	---	---
1.1 Tensile strength	ISO 37:1994	18 MPa or more	10MPa or more
1.2 Elongation	ISO 37:1994	400% or more	400% or more
1.3 Hardness	ISO 7619:1997	60 ±10 (Durometer hardness Type A)	50 ±10 (Durometer hardness Type A)
2. After ageing	ISO 188:1998	Air oven ageing, 70℃±1℃ 96h	Air oven ageing, 70℃±1℃ 96h
2.1 Tensile strength	ISO 37:1994	Not less than 80% of the original property	Not less than 80% of the original property
2.2 Elongation	ISO 37:1994	Not less than 80% of the original property	Not less than 80% of the original property
2.3 Hardness	ISO 7619:1997	Not to exceed that original property by more than 8	Not to exceed the original property by more than 8
3. Tear	ISO 34-1:1994	400 N/cm or more	No requirement
4. Compression set	ISO 815:1991	30% (70℃±1℃ for 22h) or less	No requirement
5. Static ozone ageing test	ISO 1431-1:1989	No cracks after elongation by 20% and exposure to 50 pphm^a at 40℃ for 96 h	No requirement
NOTE: If the color of the other cover is not black, the material requirements will differ from those in this table
^apphm: Parts of ozen per hundred million of air by volume.

Other type’s rubber, such as NR, EPDM, SBR, BR, are employed as per the special ingredient.

2. Synthetic-tyre-cord layer for Pneumatic Fenders (ISO17357:2002)

A. General

Synthetic-tyre-cord layers, commonly used in tyres, have been proven to provide strong efficient reinforcement layers in fenders, Each single layer is coated with rubber compound on both sides as well as in between synthetic-tyre-cord threads, hence isolating all cords from each other.

As contact between synthetic-tyre-cord threads does not occur, synthetic tyre cord has the advantage over other reinforcement materials such as canvas fabric of reducing friction and wears between cord threads during compression, bending and stretching, and also greatly improves fatigue resistance, endurance life, and pressure-holding performance.

B. Difference in arrangement of synthetic-tyre-cord and canvas-fabric reinforcement layers.

C. Example of difference in the physical property of synthetic tyre cord and canvas fabric

The synthetic-tyre-cord arrangement has strength in one direction only (warp) and the canvas-fabric arrangement strength in both direction (weft and warp). Table 1 and Table 2 provide an example of the difference in physical properties between the two.

Table 1 Synthetic tyre cord				Table 2 Canvas fabric
Item	Unit	Warp	Weft	Item	Unit	Warp	Weft
Density	Ends/inch	24	2	Density	Ends/inch	16	16
Tensile strength	N/mm²	20	0.02	Tensile strength	N/mm²	11.6	11.7