Automotive Textile || Mobiltech

Automotive Textiles (Mobiltech):

• Mobiltech (Automotive Textiles) are textile materials or products which include cars, trains, cars,buses, airplanes and marine vehicles.
• Automotive Textiles contains approximately 50 sq. yards textile materials used in average car interior trim (which includes seat covers, headliners, carpets, side panels), filters, belts, hoses, air bags, sound insulation, reinforcement etc.

Automotive Textile Includes: air bags, seat belts, seat covers, conveyor and transmission, belt fabrics, tyre cord fabrics or tyre cord yarns.

Tyre cord Fabrics:

Following are the physical properties required for textile cord material:

• It should posses good strength
• It should be adhesive to rubber
• It should have good thermal stability and good fatigue strength
• It should be flexible
• It should have low elongation and low moisture regain

Tyre Designs

Tyre Designs are categorized under following headings:

• Diagonal (Cross-ply / Bias tyre) 
• Belted Bias Tyre (Semi radial tyre)
• Radial tyre

Diagonal (Cross ply / bias tyre):

• The cord yarns make a biased angle with the tyre rolling direction
• The layers of the cord run diagonally from bead to bead at opposite bias direction

Belted bias tyre (Semi radial):

• These types of tyres are similar to a diagonal design but with additional reinforcement piles (belts) below the tread
• The presence of belts increases the stability of tread area

Radial Tyre:

• In this type of tyre design the belts are used along with the cord yarns under the belts which are arranged perpendicular to the tyre rolling direction
• It provides flexible sidewall giving longer life
• It offer better ride at high speed and has better road handling ability
• Has improved wear resistance

Tyre materials

• Polyester or nylon cords and steel belts are largely used in radial passenger tyres.
• Viscose rayon is suitable for both body and belt, nylon cord are used for bias for car and truck, radial truck tyres with steel cord belt
• Fatigue resistance is very important for tyres. Nylon has the highest resistance to dynamic stresses followed by polyester and viscose rayon.
• Polyester and glass cords are used for the production of bias and belted car tyres, polyester is used in the preparation of body and the class is used in the preparation of in belt of tyre.

Tyre Manufacturing

• During the preparation of tyres, piles(layers) of woven cord fabrics made of cords (warp) and light filling yarns(weft) are used.
• Cord (Warp)
• Cords are produced by plying several twisted filament yarns, the twist direction of each cord yarn is in opposite direction
• The cord yarns are ring twisted, direct cabled or T.F.O is used. The twist level is 10 TPI.

Filling yarn (Weft)

• The main function of filling yarn is to maintain warp spacing during handling of fabric, but they do not contribute to the performance of ply or tyre. And they can be eliminated once the warp cords are firmly place in rubber compounds.
• The count of filling yarn is finer compared to that of the cords, one to two picks per inch.
• Thread bar combs are used to maintain the uniformity of warp spacing. Cord fabric is treated with adhesives and calendar coated with rubber thickness of approximately 1mm. the filling yarns may affect the uniform distribution of tyre forces and cord geometry and hence, are broken or highly extensible filling yarns are used.

Machinery used: Rapier, Air jet and shuttle looms are used.

Air Bags

Air bags are built into the steering wheel and instrument panel, air bags are not alternative but supplemental to the seat belts as it provides protections only against head on collisions while the seat belt provide protection regardless of crash direction.

The air bag inflates from collision occurring within 60%arc in front of the vehicle.

Mechanism of Air bag:

When the crash occurs, sensors set off an igniter present in the centre of air bag, the sodium azide pellets ignite and release gases that consist of nitrogen. The gas passes through filter, ash or any other particles removed into the bag.

The air bag inflates in less than 0.04 seconds or 40 milliseconds, deflates in 0.12 seconds after absorbing the force. The entire event, from the initial impact to the full deployment takes place with in 55 milliseconds, which is half the time to blink an eye.

Materials required for Air Bag Manufacturing:

Woven fabrics with high strength, heat stability, good coating adhesion and functionality at extreme conditions, good aging characteristic and energy absorption are some of the important requirements.

Yarn requirements: 315, 420, 630 and 840 denier Nylon 6, 6 and the fabrics must be free from any kind of knots, splices, broken ends and spots.

Coating Requirements: The driver and passenger side bags are different. Driver side air bags are coated with black neoprene rubber or silicon rubber. The coating material should have good adhesion, anti blocking, low air permeability, low cost, long term flexibility. Passenger side bags are not coated as the gas disperses over large area.

Properties of Air Bags:

• Properties of Nylon 6, 6 air bag yarns
• Melting temperature : 256 degree Celsius
• Tenacity (g/d) : 7.9/ 8.4
• Elongation : 21%
• Filaments : 68/ 140
• Denier: 420/ 840

Fabric Properties:

Driver side: 25 x 25 plain weave, 840 denier, nylon 6, 6 which is scoured, heat set and coated.

Passenger side : 25 x 25 rip stop, 840 denier, nylon 6,6 heat set but not coated

Seat Belts:

The purpose of the seat belts ate to prevent forward movement of wearer in a controlled manner during sudden deceleration of the vehicle. There are different types of seat belts according to the vehicles. They are as follows:

Passenger airplanes : simple lap strap that does not restrain the upper part of the body

Passenger cars : seat belts across the lap

Racing drivers : a lap belt and a strap over each shoulder

  

Requirements of seat belts:

• It should be abrasion, heat, light resistance with flexibility for ease of use
• Carry a static load of around 1500kg with maximum extension of 25 to 30%
• High tenacity of nylon or polyester yarns should be used in warp and weft direction
• Allow the passenger to move forward around 12 inches during an accident by the controlled extension of belt.