How They Are Made
Safety matches consist of a matchstick and a striking board located on a cardboard wrapper or box. The matchstick is a wood or cardboard "splint" coated with wax and a mixture of glass, glues and chemicals containing the key ingredient potassium chlorate. The striking board is a thin layer of glass and chemicals bound with glue, containing the key ingredient red phosphorus. High-speed equipment produces the matches with a consistent quality.
How They Work
Safety matches permit a controlled burn because the oxidizer and reducing chemicals, potassium chlorate and red phosphorus, are separate until you strike the match on the friction board. The striking creates heat and sparks from the friction caused by the glass layers, and small quantities of the two chemicals react and create a flame. The wax impregnated in the match splint burns slowly and creates a controlled flame. Although a match can ignite from another match, it will not ignite on its own because it does not contain the red phosphorus component.
Safety matches are inherently safe because the reactive chemicals are separated by design but safety matches are still matches and any existing flame can ignite them. You should keep them away from flame or heat sources in the home including stoves, heaters and furnaces. Always close the cover on a matchbook or close the matchbox before rubbing the match on the friction block. Sparks from the striking of a match can ignite other matches. Do not mix safety matches with strike-anywhere matches to prevent confusion or accidental ignition.
Pasch's invention removed white phosphorus from the formulation and substituted red phosphorus. This reduced the toxicity of the match significantly. Swedish brothers Johan Edvard and Carl Frans Lundström made further improvements in the 1850s and gained additional patents. Mechanized equipment to produce matches were also invented about the same time. Sweden dominated match and safety match production well into the 20th century.