Textile is one of the earliest
inventions of our civilization. As time passed by, fabrics got refined and many textile
accessories too were invented for the comfort
of using these fabrics in an effective way. As textile became a style and fashion statement
from being a mere necessity, these simple accessories also got trendy. One of the good
examples of such accessories is the commonly used fabric closure, the button.
Journey of Button
date back to prehistoric period when they were made from stones and bones. Gradually, they began
to be made out of a variety of materials including wood, brass, pewter, gold, and silver. The buttons
were first made and used in Europe. By 18th century, the button industry flourished all across Europe,
and many different techniques for making buttons were developed by the artisans there. By the late 18th
century, metal buttons started to be made in factories but they were a bit expensive. Although, England
tried hard to stop the emigration of its die-makers, who made buttons, yet the technique spread in the
other parts of the world.
By early 20th century, inexpensive buttons, made of sea shells or other natural materials in a wide range of varieties, were available and then came the plastic buttons sometime in 1930's. After World War II, almost all the buttons were made out of plastic. They could be mold cast, where plastic slugs cut from a long rod are placed in a two-part mold. The mold is then closed, and heat & pressure applied to finish the button. In yet another process of injection molding, melted plastic is forced into a mold with a button-shaped cavity. In present times, the process most commonly followed for making buttons out of plastic is that of 'die cutting from cylinder-cast polyester'
Manufacturing Process of Buttons
The basic raw materials for making buttons is polyester, a special kind of plastic, and wax. Many chemical dyes are also added to polyester to give it different colors. Chemical catalyst is also used to harden the polyester and wax.
- Polyester, used for making buttons, is initially in liquid form. First of all, polyester is
drained from the storage tank into a stainless steel kettle. For making colored buttons, chemical dye
is added. Red carbonate, carbon black and titanium are mixed for obtaining pearl like sheen similar to
shell buttons, black and white colors respectively. After the dye has been mixed, the liquid polyester
is poured into a metal beaker having capacity of approximately 3-gallons or 11 liters. At this stage,
the chemical catalyst and liquid wax are added to the prepared mixture of polyester and the dye.
The prepared mixture is then placed into a large rotating metal cylinder made of steel and lined with chrome. The cylinder is typically 2 feet long and 4 feet in diameter. The cylinder lie on its sides on rollers which rotate the drums at about 250 rotations per minute. The polyester mixture is slowly poured into the rotating interior of the cylinder. The centrifugal force of the rotation causes the polyester solution to spread, lining the drum with an even sheet. When thicker buttons are needed, greater amount of polyester is used while less polyester is used for making thinner buttons. A 2-inch lip around the ends of the cylinder prevents the polyester solution from leaking out.
- As a result of reaction with the chemical catalyst, polyester, rotating in the cylinder, begins to harden. As the wax rises to the top of the sheet, and also sinks to the bottom, the hardening polyester is held between two layers of wax. After about 20 minutes of rotation, the polyester sheet changes from its liquid state to a crumbly solid sheet having consistency of stale cheese.
- After the hardened sheet of polyester is made, it is cut and rolled out of the cylinder onto a wooden tube. Although, it is still delicate, wax helps in removing the sheet without much effort. Top layer of the wax is then peeled off, and the sheet is placed into a blanking machine.
The blanking machine moves the polyester sheet on a conveyor belt and as the sheet passes along the belt, circular shaped cutting dies, made of steel, descend over it and punch out button-sized circles, known as blanks. Although, standard size of buttons is specified and the dies are prepared accordingly, dies with different diameters according to the requirements can also be made and loaded into the blanking machine. After the blanks are cut, they fall into a chute, and the punched out polyester sheet rolls beneath the chute. This whole process of cutting the sheets take about 2-4 minutes, depending upon the size of the buttons being made.
As the blanks are still hot, a cooling process, having hot and cold baths, follows. The blanks are placed into a nylon bag directly from the chute. The bag is placed into a tank of salt water, which is heated at 110°C, wherein the bag floats for about 15 minutes. As the water slowly cools, the polyester blanks get hardened. Then the nylon bag is transferred to a cold water tank, where the blanks reach their final state of hardness. Then the blanks are dried in a centrifugal drying machine, which spins them in a wire mesh basket.
- The final stage of button making involves designing the buttons according to the
buttons suppliers or garment companies specifications.
Different cutting tools are used for making different shaped buttons such as beveled edge, or a
slightly concave button. The cutting tool is placed in the cutting machine and the buttons are
poured into a hopper at the top of the machine. The blanks fall into a holder where they are clamped
tightly and moved toward the cutting tool. The spinning blade comes out and cuts the button and then
retracts. Then the buttons moves beneath a set of drills, which make the holes in them. The design
specification allows two or four holes, and also the diameter of the holes and the distance between
them. After the holes are made, the buttons are sucked by vacuum out of the holder and into a box
beneath the machine. Hundreds of buttons are made in a minute, though the number varies according
to the size of buttons and complexity of the design.
The buttons thus created have rough or sharp edges, scratches, and tool marks and therefore need finishing process. They are Kept into hexagonal tumbling drums, that contain water, abrasive material, and a foaming agent. The drums spin for about 24 hours. The buttons bounce around in the drum until they are smooth and shiny. Lastly, the buttons are washed and dried.
After the buttons are made, they are put on a conveyor belt and visually inspected for faults. The quality control inspector checks each button for defects and remove any cracked or mis-cut buttons. The perfectly made and finished buttons are then packaged for sale.