'

AuTx-FR Fire Protection

Higher strength, lighter weight, higher operating temperatures and flame-retardant ability are some of the most prominent physical properties of AuTx-FR fibres. These outstanding properties create opportunities to manufacture products that historically could not be made due to technical constraints. The protective clothing area is one of those markets.

Fibres with the greatest potential for producing fire resistant materials are fibres based on the chemistry of aromatic polyamides, polyimides, polyamidoimides as well as polybenzimidazoles and polyacrylonitrile (PAN, carbon fibre precursors).

While evaluating the future of using the specific fibre for the purpose of producing fire-proof clothing for; fire crew, outer covers of body amour, crew suits in fighting vehicles, etc. several factors need to be taken into the consideration:

· Fireproof properties evaluated using the limiting oxygen index number (LOI) – the percentage content of oxygen in the air that allows stable burning of the material once removed from the fire source. The greater the ON, the better fire-poof properties material has.

· Economical reasons – the price and availability of the raw materials, the simplicity of the technology etc.

The following fire resistant fibres are known and used for comparison and blending – Nomex (USA), Fenilon (Russia), Terlon (Russia), Rusar (Russia), Kermel (France), Panox (Germany), Oxalon/Arcelon (Russia/Belorussia), AuTx-FR & HT (Russia), PBI (USA).

In terms of fire-resistant properties, all of the above fibres are in a class of hard to burn materials. I.e. material’s which burn under the influence of a fire source but don’t burn by themselves after the fire source is removed.

The greatest potential method of producing fire-resistant materials uses the method of modification of the polymers (chemical or physical) with the aim of improving the fire-resistant properties. Chemical modification involves getting the co-polymers from known polymers. Physical modification involves increasing the fire-resistant properties by changing the properties of the fibre (treating, coating, etc). The creation of new polymers with increased fireproof properties usually involves major capital investment.

This is why the AuTx-FR co-polymer based on a Rusar polymer, which means chemical modification to produce a fireproof fibre at a relatively low investment.

The best fire-resistant properties in yarns are found using aromatic co-polyamides which have part of their hydrogen atoms changed for halogens. AuTx FR polymers are made using co-monomers with a different halogen containing a bi-functional bond, including chlorine. This leads to the increase of the LOI by 10-35 points. That’s why the aromatic diamine, containing chlorine, was chosen as the co-monomer.

COMPARATIVE PROPERTIES OF FIRE PROOF FIBRES

Fibre

Range

Property

Production Data

Tenacity,

СН/tex

LOI, %

Nomex

Filament yarn, fibre

49-51

22-29

Meta-aramid: Nomex® (DuPont), TeijinConex®, TeijinConex HT® (Teijin)

Fenilon

-

29-30

38-40

No

Kermel

25-35 cN/tex

30

Kermel, polyamide imides

Terlon

Filament yarn, fibre

80-100

28-30

No

Aramid

Filament yarn & Chopped yarn

45-50

25-28

Para-aramid: Kevlar® (DuPont), Twaron® (Acordis), Technora® (Teijin)

AuTx-HT

Filament yarn, fibre

230-240

28-30

Serial production at Kamenskvolokno

Basofil

Chopped yarn

32

BASF

ArTx/ Arcelon

Filament yarn, fibre

25-28

23-25

Serial production, capacity 300 tons/year (for 40 tex)

Panox

Chopped yarn and Filament

Temperature 330° LOI 50
Decomposition 880°

PBI

Chopped fibre

41

PBI Performance Products Inc, a unit of InterTech Group Inc

PBO/Zylon

Filament yarn, fibre

68

Toyobo, Japan

AuTx-FR

Filament yarn

60-80

35-70

Serial production, capacity 50 tons/year

AuTx-FR

Staple / Complex Yarn

60-80

35-70

Serial production, capacity 50 tons/year, soon to be 1,500 tons per year.

Basalt

Filament & staple

PBI has had significant success in the fireman’s apparel market where, blended in a 60/40 para-aramid/PBI mixture, it has become the standard “premium” material. PBI’s characteristic gold colour blends well with other materials.

As the result of the R&D done at Termotex and the production work done at Kamenskvolokno JSC the technical process of making the AuTx FR yarn was put into production, there is an immediate production capacity of 50 tons per year with further capacity increases possible at Novocheboxarsk of 1,500 tons per annum.

Range of the yarn is 29,4 tex and 40 tex. It isn’t toxic, can’t combust, self ignite, doesn’t smoulder, etc. after removal of the fire source.

AuTx-FR yarn properties are shown below:

Property

Permitted variation

29,4 tex

40 tex

1. Variation on the linier density, % not more

±5

±5

2. Tenacity, Cn\tex, not less

60-80

60-80

3. Coefficient of variation of the tenacity, %, not more

8

8

4. Twists per m, tw\м

120±15

120±15

5. Mass of the oil substance А1, %

1,0-2,0

1,0-2,0

Note:

Number of the twists can be changed to order.

The nominal humidity of the yarn is 4,0%. Actual humidity shouldn’t be more than 5,0%.

The colour should be from light yellow to dark yellow, the colour differentials, in the different bobbins and in the same bobbin, is allowed.

The yarn can stand the influence of a radiation dose of 10000 Mrads (Мград) in air (keeping 60% of its strength).

Heat resistance as a percentage of strength from the normal at the following temperatures:

200 0С - 82%

250 0С - 74%

300 0С - 60%

Heat resistance as the parentage of the strength from the normal at 250 0С after specific period of time:

50 hours - 96%

75 hours – 90%

100 hours – 80%

Oxygen Number, %, not less – 40

Catching the fire if the edge is under the fire at 960 0С, seconds - 4.

A combined fabric based on AuTx FR filament yarn and spun ArTx yarn was developed to improve the comfort of the fabric for the user and to decrease its price.

Provisional information on the testing of combined (AuTx FR & ArTx) fabric, article 11 950

1.Description:

- yarn tex - 90

- width of the fabric, см - 100

- density grm/м2 - 282

2. Tenacity and elongation at break according to the GOST standard 29104.4-91:

- warp -170Kgs and 15% accordingly,

- weft -170kgs and 7.7% accordingly.

3. Influence of different factors on the fabric:

- petrol,

- diesel fuel,

- liquid POSH- 70M (ПОЖ-70М).

The results of tests carried out according to the GOST 29104.4-91 and GOST 29014.13-91 standards showed that the strength of the fabric almost does not change after being subjected to the above tests for 3 days at ambient room temperature.

Shrinking of the fabric after influence of the different liquids is within the limits set for synthetic fabrics (±3.5% along the warp, ±2.0% along the weft) – see the table below.

Fabric

Shrinking, % after influence of the outer factors

Petrol

Diesel fuel

(ПОЖ-70М)

Fire proof fabric made by combining AuTx FR & ArTx fibres.

warp

-0.3

0

-0.3

weft

0

0

-0.3

4. The evaluation of the fire-resistant properties done according GOST15898-70.

The result of the testing is:

1) After influence of the fire along the warp and weft yarn for 10 seconds the fabric doesn’t burn, the smouldering after removal fire source 2-3 seconds.

2) After influence of the fire along the warp and weft yarn for 30 seconds the fabric doesn’t burn, but gets chard, the smouldering after removal fire source 2-3 seconds.