Bullet Proof/Resistant Vest

Rana Ali Haider14-NTU-0140

National Textile University

Presented By:

A ballistic vest or bullet-resistant vest, often called a bulletproof vest, is an item of personal armor that helps absorb the impact and reduce or prohibit penetration to the body from firearm-fired projectiles and shrapnel from explosions. Soft vests are made from many layers of woven or laminated fibers and can be capable of protecting the wearer from small-caliber handgun and shotgun projectiles, and small fragments from explosives such as hand grenades.

Introduction

Metal or ceramic plates can be used with a soft vest, providing additional protection from rifle rounds, and metallic components or tightly woven fiber layers can give soft armor resistance to stab and slash attacks from knives and similar close-quarter weapons. Soft vests are commonly worn by police forces, private citizens who are at risk of being shot (e.g., national leaders), security guards, and bodyguards, whereas hard-plate reinforced vests are mainly worn by combat soldiers, police tactical units, and hostage rescue teams.

In 1538, Francesco Maria Della Rovere commissioned Filippo Negroli to create a bulletproof vest. In 1561, Maximilian II, Holy Roman Emperor is recorded as testing his armor against gun-fire.

One of the first commercially sold bulletproof armor was produced by a tailor in Dublin, Ireland in the 1840s. The Cork Examiner reported on his line of business in December 1847.

History

Commercially used synthetic fibers include Kevlar, Spectra, Twaron, Ballistic Nylon and Zylon.

Mostly used material for bulletproof vest is Kevlar.

Kevlar is not used in pure form because it has some drawbacks.

Use of Spectra for vests is also increasing now a days.

Raw Materials:

It is degraded by the UV Rays.Low stability under wet conditions because

Kevlar has low strength under wet conditions.

Therefore, Kevlar is blended with a natural fiber which is mostly Wool.

Drawbacks of using Pure Kevlar fiber:

Advantages:Better tear strength even under wet conditions.Better energy absorbing capacity and reduced

number of layers in a vest.Better breathability and feels good on skin.Restricts the displacement of Kevlar yarns

under the impact of bullet.Increases the friction at yarn intersections and

penetrating bullet comes across a stronger resisting force.

Blended fabric of Wool and Kevlar:

To make Kevlar, the polymer poly-para-phenylene terephthalamide is first produced in the laboratory. This is done through a process known as polymerization, which involves combining molecules into long chains. The resultant crystalline liquid is then extruded through a spinneret to form Kevlar yarn. The Kevlar yarn then passes through a coagulation bath to help it harden.

Manufacturing of Kevlar Filament:

The Kevlar yarn is then twisted to make it suitable for weaving. To make Kevlar cloth, the yarns are woven in the simplest pattern, plain weave, which is merely the over and under pattern of threads that interlace alternatively.

Fabric Technique:

Spectra used in bulletproof vests is usually non woven. Resin is used to coat the fibers, sealing them together to form a sheet of Spectra cloth. Two sheets of this cloth are then placed at right angles to one another and again bonded, forming a nonwoven fabric that is next sandwiched between two sheets of polyethylene film.

Manufacturing of Spectra shield:

The cloth is then laid out on the cutting table.Layers of fabric depends on the protection

needed.Minimum 8 layers are used and maximum 25.Layers are cut with a cutting machine

according to the shape required.

Cutting the Panels for Vest:

Panels are stitched by Standard Industrial Sewing machines using the Kevlar thread for sewing.

These panels are then placed in the shells of Polyester-Cotton blended fabric which gives extra comfort to the wearer.

These panels are then placed in a Garment which is of shape of a garment.

Number of layers of fabric define the strength of vest against bullet.

Stitching of the panels:

Accessories are sewn on the vest such as Straps etc.

A size tag is also attached on the vest.The finished vest is then boxed to the

customer.

Finishing the Vest:

It’s Chemical structure.

What makes Kevlar bullet Resistant?

How bullet is Resisted?

Components of Bullet Proof Vest:

Applications:Used by Army, Police, Security agencies,

Famous Personalities etc.