Hypercolor
Encyclopedia
Hypercolor was a line of clothing, mainly T-shirt
s and shorts
, that changed color
with heat.
They were manufactured by Generra Sportswear Company of Seattle and marketed in the United States
as Generra Hypercolor or Generra Hypergrafix and outside the US as Global Hypercolor. They contained a thermochromic
(temperature
sensitive) pigment made by Matsui Shikiso Chemical
of Japan
, that changed between two colors – one when cold, one when warm. The shirts were produced with several color change choices beginning in 1991. The effect could easily be permanently damaged, particularly when the clothing was washed in hotter than recommended water, ironed
, bleach
ed or tumble-dried
.
Generra Sportswear Co. had originally been founded as a men's sportswear distributor
and importer in Seattle in 1980. The company was sold to Texas
-based Farah Manufacturing Co. in 1984 and bought back by its founders in 1989. In 1986, the company added childrenswear and womenswear items to their portfolio. They struggled to meet the overwhelming demand
for Hypercolor products. Between February and May 1991 they sold $50 million in Hypercolor garments. Generra went bankrupt
due to mismanagement and fading demand in 1992. The Hypercolor business for the U.S. market was sold to Seattle T-Shirt Company in 1993; Generra kept the rights for the international market. The company emerged from bankruptcy in 1995 as a licensing business. The Generra name was acquired by Public Clothing Co. of New York in 2002. Today, Generra Co. is a contemporary women's and men's apparel brand headquartered in New York City.
In the early 2000s, the technique was revived by a number of apparel brands.
s (used in mood ring
s) and leuco dye
s (used in Hypercolor T-shirts).
The color change of Hypercolor shirts is based on combination of two colors: the color of the dyed fabric, which remained constant, and the color of the thermochromic dye. The dye is enclosed in microcapsules, tiny (few micrometers in diameter) drops of liquid sealed in a transparent shell, bound to the fibers of the fabric.
When it is cold the mixture in the capsule is solid and the carbon molecules in the leuco dye are attached to each other in a ring shape. When the capsule experiences a rise in temperature the molecules change shape, just like liquid crystals. They break open the carbon ring. This change means that the dyes absorb and release light differently, and the color seen is different.
The liquid is a leuco form of a dye (in this case crystal violet lactone
), a weak acid
(benzotriazole), and a quaternary ammonium salt of a fatty acid
(myristylammonium oleate) dissolved in a solvent (1-dodecanol
). At low temperatures, the weak acid forms a colored complex with the leuco dye, interrupting the lactone
ring. At high temperatures, above 24-27 °C, the solvent melts and the salt dissociates
, reversibly reacts with the weak acid and increases the pH
. The pH change leads to closing of the lactone ring of the dye, which then regains its colorless (leuco) form.
Therefore, at the low temperature the color of the shirt is the combination of the color of the microcapsules with the color of the dyed fabric, while at higher temperatures the capsules become colorless and the color of the fabric prevails.
T-shirt
A T-shirt is a style of shirt. A T-shirt is buttonless and collarless, with short sleeves and frequently a round neck line....
s and shorts
Shorts
Shorts are a bifurcated garment worn by both men and women over their pelvic area, circling the waist, and covering the upper part of the legs, sometimes extending down to or even below the knee, but not covering the entire length of the leg. They are called "shorts" because they are a shortened...
, that changed color
Color
Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
with heat.
They were manufactured by Generra Sportswear Company of Seattle and marketed in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
as Generra Hypercolor or Generra Hypergrafix and outside the US as Global Hypercolor. They contained a thermochromic
Thermochromism
Thermochromism is the ability of substance to change color due to a change in temperature. A mood ring is an excellent example of this, but it has many other uses such as baby bottles and kettles. Thermochromism is one of several types of chromism.The two basic approaches are based on liquid...
(temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
sensitive) pigment made by Matsui Shikiso Chemical
Matsui Shikiso Chemical
Matsui Shikiso Chemical Co., Ltd was founded in 1911 by Kenji Matsui. Matsui Shikiso Chemical started offering a wide variety of products, mainly inks and pigments, targeted principally to the textile screen printing industry...
of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, that changed between two colors – one when cold, one when warm. The shirts were produced with several color change choices beginning in 1991. The effect could easily be permanently damaged, particularly when the clothing was washed in hotter than recommended water, ironed
Ironing
Ironing is the use of a heated tool to remove wrinkles from fabric. The heating is commonly done to a temperature of 180-220 °Celsius, depending on the fabric. Ironing works by loosening the bonds between the long-chain polymer molecules in the fibers of the material...
, bleach
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...
ed or tumble-dried
Clothes dryer
A clothes dryer or tumble dryer is a household appliance that is used to remove moisture from a load of clothing and other textiles, generally shortly after they are cleaned in a washing machine....
.
Generra Sportswear Co. had originally been founded as a men's sportswear distributor
Distribution (business)
Product distribution is one of the four elements of the marketing mix. An organization or set of organizations involved in the process of making a product or service available for use or consumption by a consumer or business user.The other three parts of the marketing mix are product, pricing,...
and importer in Seattle in 1980. The company was sold to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
-based Farah Manufacturing Co. in 1984 and bought back by its founders in 1989. In 1986, the company added childrenswear and womenswear items to their portfolio. They struggled to meet the overwhelming demand
Demand
- Economics :*Demand , the desire to own something and the ability to pay for it*Demand curve, a graphic representation of a demand schedule*Demand deposit, the money in checking accounts...
for Hypercolor products. Between February and May 1991 they sold $50 million in Hypercolor garments. Generra went bankrupt
Bankruptcy
Bankruptcy is a legal status of an insolvent person or an organisation, that is, one that cannot repay the debts owed to creditors. In most jurisdictions bankruptcy is imposed by a court order, often initiated by the debtor....
due to mismanagement and fading demand in 1992. The Hypercolor business for the U.S. market was sold to Seattle T-Shirt Company in 1993; Generra kept the rights for the international market. The company emerged from bankruptcy in 1995 as a licensing business. The Generra name was acquired by Public Clothing Co. of New York in 2002. Today, Generra Co. is a contemporary women's and men's apparel brand headquartered in New York City.
In the early 2000s, the technique was revived by a number of apparel brands.
Principle
Substances that can change color due to a change in temperature are called thermochromes. There are two types of thermochromes: liquid crystalLiquid crystal
Liquid crystals are a state of matter that have properties between those of a conventional liquid and those of a solid crystal. For instance, an LC may flow like a liquid, but its molecules may be oriented in a crystal-like way. There are many different types of LC phases, which can be...
s (used in mood ring
Mood ring
A mood ring is a ring which contains a thermochromic element, such as liquid crystal. The ring changes color in response to the body temperature of its wearer...
s) and leuco dye
Leuco dye
A leuco dye is a dye whose molecules can acquire two forms, one of which is colorless.For example, the spiro form of an oxazine is a colorless leuco dye; the conjugated system of the oxazine and another aromatic part of the molecule is separated by an sp3-hybridized "spiro" carbon...
s (used in Hypercolor T-shirts).
The color change of Hypercolor shirts is based on combination of two colors: the color of the dyed fabric, which remained constant, and the color of the thermochromic dye. The dye is enclosed in microcapsules, tiny (few micrometers in diameter) drops of liquid sealed in a transparent shell, bound to the fibers of the fabric.
When it is cold the mixture in the capsule is solid and the carbon molecules in the leuco dye are attached to each other in a ring shape. When the capsule experiences a rise in temperature the molecules change shape, just like liquid crystals. They break open the carbon ring. This change means that the dyes absorb and release light differently, and the color seen is different.
The liquid is a leuco form of a dye (in this case crystal violet lactone
Crystal violet lactone
Crystal violet lactone is a leuco dye, a lactone derivate of crystal violet 10B. In pure state it is a slightly yellowish crystalline powder, soluble in nonpolar or slightly polar organic solvents....
), a weak acid
Weak acid
A weak acid is an acid that dissociates incompletely. It does not release all of its hydrogens in a solution, donating only a partial amount of its protons to the solution...
(benzotriazole), and a quaternary ammonium salt of a fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
(myristylammonium oleate) dissolved in a solvent (1-dodecanol
Dodecanol
Dodecanol, also known by its IUPAC name 1-dodecanol or dodecan-1-ol, and by its trivial name dodecyl alcohol and lauryl alcohol, is a fatty alcohol. Dodecanol is a colourless, water insoluble solid of melting point 24 °C and boiling point 259 °C. It has a floral odor...
). At low temperatures, the weak acid forms a colored complex with the leuco dye, interrupting the lactone
Lactone
In chemistry, a lactone is a cyclic ester which can be seen as the condensation product of an alcohol group -OH and a carboxylic acid group -COOH in the same molecule...
ring. At high temperatures, above 24-27 °C, the solvent melts and the salt dissociates
Dissociation (chemistry)
Dissociation in chemistry and biochemistry is a general process in which ionic compounds separate or split into smaller particles, ions, or radicals, usually in a reversible manner...
, reversibly reacts with the weak acid and increases the pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
. The pH change leads to closing of the lactone ring of the dye, which then regains its colorless (leuco) form.
Therefore, at the low temperature the color of the shirt is the combination of the color of the microcapsules with the color of the dyed fabric, while at higher temperatures the capsules become colorless and the color of the fabric prevails.
External links
- "Thermochromic Fabric Displays," HowStuffWorksHowStuffWorksHowStuffWorks is a commercial edutainment website that was founded by Marshall Brain with the goal of giving its target audience an insight into the way in which many things work. The site uses various media in its effort to explain complex concepts, terminology and mechanisms, including...