Compositions – Fire retarding – For wood or cellulosic material other than textile
Reexamination Certificate
1999-08-23
2001-11-20
Warden, Jill (Department: 1743)
Compositions
Fire retarding
For wood or cellulosic material other than textile
C252S601000, C252S603000
Reexamination Certificate
active
06319431
ABSTRACT:
BACKGROUND OF THE INVENTION
THIS invention relates to a preservative and fire retardant composition and combination and process.
Cellulosic materials, typically wood and wood derivatives, such as cardboard and products comprising them, need to be protected against the risk of fire and against biological degradation as a result of decay caused by fungi and attack by insects such as wood borers and termites. Borates in low concentrations have been used as wood preservatives as they provide wide-spectrum protection against organisms causing wood degradation. Borates in high concentrations have also been used to treat wood against fire. However, the use of high concentrations of borates is expensive and uneconomical. Also, borates have a relatively low solubility in aqueous solvents and it is therefore difficult to formulate a suitable composition for impregnation. Borates are also leachable from wood and other cellulosic materials which can result in their loss from treated cellulosic materials when they are exposed to continuous wet conditions, in particular free water.
Other cellulosic materials such as thatching grass, reeds, bamboo and palm leaves are also used in root and wall construction. These also need to be protected against the risk of fire and against biological degradation. However, to date the treatment of such materials has posed problems because the waxy and/or protective coating on the surface of such materials precludes sufficient penetration of treatment materials.
SUMMARY OF THE INVENTION
According to one aspect of the invention all aqueous treatment composition for cellulosic material comprises an aqueous fire retardant solution of urea (CO(NH
2
)
2
, a source of inorganic acid groups, a water miscible alcohol and an inorganic borate.
According to a further aspect of the invention a concentrated treatment composition for cellulosic material comprises an aqueous fire retardant solution of urea (CO(NH
2
)
2
), a source of inorganic acid groups, a water miscible alcohol and an inorganic borate, which are present in the following amounts:
water
100 to 180 g/kg;
urca
270 to 560 g/kg;
inorganic acid
90 to 150 g/kg;
water miscible alcohol
30 to 75 g/kg;
inorganic borate
180 to 440 g/kg.
The urea is preferably present in an amount of 310 to 500 g/kg.
The water is preferably present in an amount of 120 to 160 g/kg.
The source of inorganic acid groups is preferably phosphoric acid. The phosphoric acid is preferably present in an amount of 100 to 130 g/kg.
The source of inorganic acid groups may also be monoammonium phosphate (MAP) (NH
4
H
2
PO
4
) or diammonium phosphate (DAP). If MAP is used, it is preferably present in substantially the same amounts given for phosphoric acid mentioned above. The MAP used is typically at 100% purity and therefore contains about 82,565% PO
4
.
The water miscible alcohol is preferably ethanol. The ethanol is preferably present in an amount of 35 to 65 g/kg, more preferably 40 to 60 g/kg.
The inorganic borate may be boric acid (H
3
BO
3
) or sodium borate (Na
2
B
4
O
7
) or both. It is preferably a mixture of boric acid and sodium borate. In the mixture of boric acid and sodium borate, the boric acid is preferably present in an amount of 110 to 270 g/kg, more preferably 130 to 240 g/kg and the sodium borate is preferably present in an amount of 70 to 170 g/kg, more preferably 80 to 150 g/kg.
According to another aspect of the invention a treatment kit for cellulosic material comprises
a first container containing a water miscible alcohol; and
a second container containing an inorganic borate,
the first container and/or the second container additionally containing urea and/or a source of inorganic acid groups, provided that if the urea or the source of inorganic acid groups are in a liquid form they are contained in the first container and if they are in a dry form, they are contained in the second container, the contents of the second container, dissolved in water if necessary, being miscible with the contents of the first container to form an aqueous treatment composition for cellulosic material.
A preferred treatment kit for cellulosic material comprises:
a first container containing an aqueous fire retardant solution of urea, a source of inorganic acid groups and a water miscible alcohol; and
a second container containing an inorganic borate,
the contents of the second container being miscible with the contents of the first container to produce an aqueous treatment composition for application to the cellulosic material.
The contents of the second container are soluble in water.
The inorganic borate may be boric acid (H
3
BO
3
) or sodium borate (Na
2
B
4
O
7
) or both.
It is preferably a mixture of boric acid and sodium borate.
The aqueous treatment composition preferably contains 1 part boric acid equivalent (mass per volume) of boric acid, sodium borate or both to 2.5 to 5 parts aqueous fire retardant solution (volume per volume).
The treatment composition and the second container preferably contain both boric acid and sodium borate as a dry salts mixture.
The sodium borate is preferably in the form of a borax pentahydrate (Na
2
B
4
O
7
5H
2
O).
The dry salts mixture preferably contains about 940 g per kg of boric acid equivalent.
The dry salts mixture may contain from about 465 to 775 g per kg of boric acid and from about 285 to 475 g per kg of borax pentahydrate.
The dry salts mixture preferably contains from about 590 to 650 per kg of boric acid and 360 to 400 g per kg of borax pentahydrate.
The source of inorganic groups is preferably a water soluble source of phosphate groups.
The water soluble source of phosphate groups may be phosphoric acid or monoammonium phosphate.
The phosphoric acid may be present in the aqueous treatment composition or in the aqueous fire retardant solution in the first container in an amount of from 75 to 125 g per liter, preferably from 90 to 110 g per liter.
The urea may be present in the aqueous treatment composition or in the aqueous fire retardant composition in the first container in an amount of from 300 to 500 g per liter, preferably from 360 to 440 g per liter.
The water soluble alcohol is preferably a non-polymerisable alcohol.
The water soluble alcohol may be ethyl alcohol or methyl alcohol, preferably ethyl alcohol.
The ethyl alcohol is preferably present in the aqueous treatment composition or in the aqueous fire retardant solution in the first container in an amount of from 35 to 65 g per liter, preferably from 45 to 55 g per liter.
A further preferred treatment kit for cellulosic material comprises:
a first container containing a source of inorganic acid groups and a water miscible alcohol; and
a second container containing an inorganic borate and urea,
the contents of the second container being soluble in water and the contents of the first container being miscible with the contents of the second container dissolved in water in a ratio of 0.1 to 0.4:1 (volume per mass) to form a treatment composition for cellulosic material.
The ratio is preferably 0.15 to 0.30:1 (volume per mass).
The source of inorganic acid groups is preferably phosphoric acid. The phosphoric acid is preferably present in an amount of 500 to 910 g/kg, preferably 600 to 800 g/kg.
The water miscible alcohol is preferably ethanol. The ethanol is preferably present in an amount of 200 to 410 g/kg, preferably 240 to 360 g/kg.
The urea is preferably present in an amount of 370 to 810 g/kg, more preferably 450 to 720 g/kg.
The inorganic borate may be boric acid or sodium borate. It is preferably a mixture of boric acid and sodium borate. In the mixture of boric acid and sodium borate, the boric acid is preferably present in an amount of 160 to 390 g/kg, more preferably 190 to 340 g/kg and the sodium borate is preferably present in an amount of 100 to 240 g/kg, preferably 120 to 210 g/kg.
Yet another preferred treatment kit for cellulosic material comprises:
a first container containing a water miscible alcohol; and
a second container containing an inorganic borate, urea and a source of inorganic acid groups in
Basson Gabriel Richter
Conradie Wilhelm Eduard
Birch & Stewart Kolasch & Birch, LLP
Cross LaToya
Futuratec CC
Warden Jill
LandOfFree
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