Unsaturated polyester resin made from petroleum is used. Because of its thermosetting feature,it has been extensively used to make buttons in apparel. In 1955, a technique using polyester resin to represent the glossy effect of shell was invented in the U.S.A. This development replaced acrylic buttons,which had been mainly used up to then. As a substitute for shell buttons,polyester buttons spread all over Japan and they occupy a great share in the global button production now. Without limits to designs, tremendous patterns can be made to show natural appearances,such as buffalo horn,shell and nut materials,and depending on the different designs,there is a different making process for each. One of the typical methods is using an aluminum rod into which is poured polyester solution and heat is applied to harden the material,this is called "rod" material. Another way is pouring polyester solution into a large rotating metal cylinder and with centrifugal force,it forms a sheet of polyester,this is called "sheet" material. Combinations with other materials such as metal,acrylic,shell makes polyester buttons more appealing in the market.
ABS is a resin compounded of the three plastics ? Acrylonitrile, Butadiene & Styrene - and have the respective properties; Acrylonitrile - heat resistible, hardness, petroleum resistance, weather resistance. Butadiene ? elasticity. Styrene - glossy effect, excellent electrical properties, impact resistance. It is known as the best material of the resin materials to plate buttons and the injection method is used. In Japan,after 1970,as a substitute for metal buttons,ABS buttons came into common use and are frequently combined with other materials.
Brass and zinc as the main raw materials. Metal buttons come in a tremendous variety of colors. Brass buttons are often seen on uniforms or blazers. Because brass has a soft property, embossing or cutting processes are frequently used for production. Most brass buttons are formed by putting the top and bottom parts together with a press / die set and the inside of the button is hollow. More meticulous designs can be presented by die casting buttons. Zinc alloy is melted by extremely high temperatures and is poured into a metal mould to produce buttons. For the delicate designs, the rubber casting method is used. Metal buttons are widely seen as uniform or branded buttons worldwide.
Nylon resin came into use as a new material for buttons around 1960. Nylon is a genetic designation of Polyamide. Nylon products are usually processed by injection molding. For example,to meet the increasing demands for combination products,metal parts can be combined without adhesive during the processes of injection. Nylon products are rich in appearance and various patterns can be designed,such as close texture,leathers,barks and meticulous motifs. Transparent or pearly effects can be made as well. Nylon products have a high production rate,are light and have great color fastness for dyeing.
Urea buttons have excellent color fastness and are excellent substitutes for horn and nut materials. Urea is a unique plastic material, which was developed to convey the natural appearances of wood, horn and nut materials. We at IRIS have incorporated the techniques and machinery from Italy into our production system. Since it is not dyeable, all colors are mould-dyed. Each color of sheet is formed and each sheet is set to make natural look appear. The ready material is pushed into the machine to form into a round bar, then it is cut into tablets. Each tablet is set in the metal mould and compressed with heat-treatment to make into buttons. Compared with other materials,urea buttons have excellent properties of resistance to weather,impact,chemicals and heat. Due to its minimum quantities,urea buttons meet the need of mass production market.
Raw shell materials for buttons are mainly obtained in the Southern Pacific Oceans. White mother-of-pearl shells, black-mother-of-pearl shells, Takase shells and Mexican Abalone shells are commonly used, but almost all of them are imported. Being natural, the quality of material is graded by its habitat. Takase shell is the most frequently used and it comes in variety forms of buttons from thin 2 or 4-hole style to shank style. Takase shell is a spiral shell in conic shape,while other shells are bivalves (two-halve shells like mussels). Because of its excellent pearly effects and superb luster, white mother-of-pearl shell is ranked at the top and it fits very well with the elegant and luxurious wears. For a long time, shell buttons had been a hand-made production before machinery was invented in the 19th.century. Most of the production processes are cutting processes to treat the outer shells, and long-experienced skilled techniques are especially required for the finishing processes.
Ecuadorian coconut(Corozo Nut) is the raw material. It is known as "Ivory nuts" or "Vesitable nuts", as the outer of the seed looks like ivory once the shell of the nut is removed. The fine grain and gloss are distinctive. Buttons are made by slicing the nut into an appropriate thickness, taking out the blanks and forming each blank into a button by cutting. The final process is polishing to make the button shiny. This production process was originally developed and put into automation in Germany and spread into northern Italy. Nut buttons are commonly used with menswear.
After nuts and shells had been originally used as accessories ones, horns and hooves came into use. In the ancient Greek era, these were valuable jewellery equivalent to gold and silver. Slicing solid horns or splitting hollow horns in half, blanks are taken out to make buttons. The tip of horns is frequently used as toggle buttons. In the 19th. century, decorative horn buttons were developed by applying pressure to make a relief on it. With this method, the portrait of Josephine and Marie-Louise (the first and the second wife of Napoleon) was embossed on the button.
From ancient times to present, wood buttons have been long made. Woods buttons were made by being carved out of a single board of boxwoods, magnolias, cherries, ebonies or olives. But nowadays, plywood is the main material. The main trees of plywood are birches, beeches and lauans. Phenol resin is impregnated and after it is naturally dried outside for a half day, it is dried for another three hours inside with the heat at 60 to 70 centigrade. To make the buttons, cutting processes are conducted. To make the best use of fine grains, a burning effect can be applied or wood buttons can be combined with other materials. Even the color inconsistency of wood buttons conveys the sense of natural beauty.
Skins of cows, horses and goats are the raw material of leather buttons. The hides are mainly imported from America and Australia. They are tanned by treatment with tannic acid or chrome. The hide with the tannin treatment is used for buttons. Leather is cut and shaved off to appropriate kinds of forms for button production.. Putting leather strings together by artisans or embossing a design on a plain leather sheet, leather is made into buttons. Artificial animal skins can be represented by embossing a single sheet of plain leather. Taking different textures between top and back of the leather into design or showing different tones like distressed appearance with additional processes, distinctive features of leather gives buttons a unique accent. It is said that a wide variety of leather buttons were made in the 19th.century. In the present day, leather buttons are regularly used on coats.
In the late 1920, production of casein buttons spread the world after the development of machinery in Germany made its production automatic. In Japan it was called "Lact" and put into the market from around 1930. The raw material of casein buttons is rennet casein, which is made from milk. Casein is a genuine dairy product. To give buttons luster or patterns, white pigment, pearl essence or water are added to the rennet casein and compounded with heat and pressure treatment. Being formed into a bar or a sheet, drying them for a long time before making buttons. Through its processes,it requires time and care with skilled artisans. High compression resistance and chemical resistance, excellent colorfastness for dyeing are the great properties of casein buttons.