[0001] This invention relates to matches. In particular the invention relates to matches
incorporating a fire-retardant material such that the match extinguishes itself soon
after ignition. Such matches are safer than ordinary matches in that unintentional
fires due to the continued burning of the match after the required use are avoided,
thus reducing the incidence of, for example, forest fires or injuries to children.
[0002] In U.S. Patent No. 4,072,473 there is described a process for the manufacture of
cardboard book matches, the matches incorporating chemical fire-retardant material
effective to extinguish the matches after ignition. In this patent the book matches
are manufactured by a process in which one end of the cardboard match splints are
impregnated with hot paraffin wax so as to assist the combustion of the matches, the
opposite ends of the splints then being dipped into a fire retardant material. Such
a process is, however, difficult to control due to the different absorption of the
paraffin wax into the splints at different temperatures. Furthermore, where the flame-retardant
material reaches the paraffin wax on the splints, spluttering of the wax may occur,
thus inhibiting the extinction of the matches.
[0003] It is an object of the present invention to provide a match incorporating a fire-retardant
material, together with a process for making such a match, wherein the above difficulties
are, at least, alleviated.
[0004] According to a first aspect of the present invention, a method of manufacturing a
match includes the steps of: coating a portion of a porous match splint with a layer
of paraffin wax at a temperature such that a substantial part of the paraffin wax
remains on the surface of said portion of the splint, coating the splint with a fire-retardant
material such that the material does not adhere to said portion of the splint, and
coating part of said portion of the splint with paraffin wax at a temperature such
that a part of said paraffin wax layer is absorbed into the splint.
[0005] The splint is suitably coated with paraffin wax by means of a dipping process.
[0006] According to a second aspect of the present invention, a match comprises: a porous
match splint having a first portion coated with paraffin wax, a substantial part of
the paraffin wax being absorbed into the first portion of the splint; a second portion
of the splint coated with paraffin wax, the second portion of the splint containing
less absorbed paraffin wax than the first portion of the splint; a third portion of
the splint carrying a fire-retardant material; and a quantity of an ignition material
carried on the free end of said first portion of the splint.
[0007] The fire-retardant material is suitably monoammonium phosphate.
[0008] One match in accordance with an embodiment of the invention, together with a process
for making the match, will now be described by way of example only, with reference
to the accompanying Figure which is a schematic diagram of the match.
[0009] Referring to the Figure, the match in accordance with the embodiment of the invention
comprises a wooden match splint 1 on which is carried a match head 3 of conventional
pyrotechnic composition. The match splint 1 is divided into three zones 5,7,9. In
the first zone 5, in the region of the head 3, a substantial amount of paraffin wax
is absorbed into the splint 1. In the intermediate zone 7, next to the zone 5, a smaller
amount of wax is absorbed into the splint 1 than in the first zone 5. Finally, at
the end of the match remote from the head 3, the zone 9 is covered in fire-retardant
material.
[0010] The zone 5 is typically 5mms long, with the zone 7 also being typically 5mms long.
[0011] The match is formed by the following process. Firstly, the match splint 1 is dipped
into cold, but molten, paraffin wax so as to coat up to the first 10mm of the splint
1 including the zones 5,7. The whole splint 1, apart from the 6-8mm which is gripped
by the match plate, is then coated with fire-retardant material, for example monoammonium
phosphate. This material will not adhere to the zones 5,7 of the splint 1 previously
coated with wax, thus leaving only zone 9 covered with fire-retardant material, part
of the material being absorbed into the zone 9 of the splint 1. The splint 1 is then
dipped in a conventional hot paraffin wax bath, so as to coat the 5mms of the splint
1 corresponding to the first zone 5, on top of the cold wax already provided on the
splint 1. The hot wax ensures that the paraffin wax in the zone 5 is totally absorbed
into the splint 1, conduction of the heat from the hot wax causing a smaller amount
of wax in the zone 7 also to be absorbed into the splint 1. The head of the match
3 is then applied to the free end of the zone 5 by conventional means.
[0012] It will be seen that by use of the above sequence of steps, the necessary adherence
of both the wax and the fire-retardant material to the splint is achieved. Furthermore,
as the fire-retardant material is provided only in the zone 9 remote from the zone
5 in which most of the wax is absorbed, the problem of spluttering of the wax necessary
for efficient combustion of the match is avoided. The zone 7, in which only a small
portion of wax is absorbed into the splint 1, provides an intermediate region which
helps to resolve the conflicting requirements of the combustion of the match, as assisted
by the zone 5, and the extinction of the combustion as assisted by the zone 9.
[0013] It will be appreciated that any suitable flame- retardant material may be incorporated
in the region 9, other than monoammonium phosphate. Suitable materials include, diammonium
phosphate, ammonium sulphate, and ammonium chloride.
[0014] Furthermore, any porous match splint may be used, for example cardboard or stiff
paper.
1. A method of manufacturing a match including the step of coating a portion of a porous
match splint (1) with a layer of paraffin wax, the method being characterised in that
the layer of paraffin wax is at a temperature such that a substantial part of the
paraffin wax remains on the surface of said portion (5,7) of the splint (1), and that
the method also includes the steps of coating the splint (1) with a fire-retardant
material such that the material does not adhere to said portion (5,7) of the splint
(1), and coating part (5) of said portion (5,7) with paraffin wax at a temperature
such that a part of said paraffin wax layer is absorbed into the splint (1).
2. A method of manufacturing a match according to claim 1, in which the splint (1) is
coated with paraffin wax by means of a dipping process.
3. A method according to either one of the preceding claims in which the fire-retardent
material is monammonium phosphate.
4. A method according to any one of the preceding claims in which the porous match splint
(1) is a wooden splint.
5. A match comprising a porous match splint (1) having a first portion (5) coated with
paraffin wax, a substantial part of the paraffin wax being absorbed into the first
portion of the splint, the match being characterised in that a second portion (7)
of the splint (1) is coated with paraffin wax, the second portion (7) of the splint
(1) containing less absorbed paraffin wax than the first portion (5) of the splint
(1); a third portion (9) of the splint (1) carries a fire-retardant material; and
a quantity (3) of an ignition material is carried on the free end of said first portion
(5) of the splint.
6. A match according to claim 5 in which the fire-retardant material is monammonium phosphate.
7. A match according to claim 6 or claim 7 in which the porous match splint (1) is a
wooden splint.