Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CIL 596
This invention relates to an emulsion blasting
agent of the type having an aqueous salt solution discon-
tinuous phase, a liquefiable carbonaceous fuel continuous
phase and containing occluded gas bubbles or gas-containiny
material as a further discontinuous phase. In particular,
the invention describes a gas-containing emulsion explosive
composition which has enhanced sensitivity even after pro-
longed storage and which, though devoid of any self-explosive
ingredient, may be detonated in very small diameter charges.
Emulsion type explosive composi~ions are now well
known in the e~plosives art. Bluhm, in United States patent
No. 3,447,978, disclose~ a composition comprising all a~ueous
discontilluous phase containing dissolved oxygen-~upplying
~alts, a carbonaceous fual continuous phase, an occluded gas
and a water-in-oil emulsifying agent. Optional particulate
carbonaceous or metal fuel can be included. The composition5
of Bluhm are somewhat limited in utility since detonation is
possible only with relatively large diameter charges and the
compositions require initiation by means of a substantial
primer. Cattermore et al., in United States patentNo 3,674,578
describe a water-in oil emulsion explosive comprising an in-
organic salt, a nitrogen-base salt such as an amine nitrate,
water, a water-insoluble oil as ~uel, an emulsifier for the
oil and incorporated gas bubbles. The composition of
Cattermole, while detonable in charges having diameters of
as little as 2 inches, requires the use of a nitrogen-base
salt, e g. ethylenediamin~ dinitrate, which is per se a self-
explosive material. Wade, in United States patent No. 3,715,247,
des~ribes a small-diameter cap-sensitive emulsion type explosive
composition comprising carbonaceous fuel, water, inorganic
-- 1 --
'-~i ,3~,;
~13~
salts, an emulsifier, gas bubbles, and a detonation catalyst
consisting of a water-soluble salt containing selected metals.
Wada, in United States patent No. 3,765,964, describes an im-
provement in the composition of United States patent No.
3,715,247 by including therein a water-soluble strontium
compound to provide further sensitivity. In applicant's
copending Canadian application Serial No. 317,649 filed on
December 8, 1978, there is described a sensitive emulsion
type explosive composition containing fuel~ water, salts,
gas bubbles, an emulsifier and an emulsification promoter
cvmprising a highly chlorinated paraffinic hydrocarbon.
Wade again, in United States patent No. 4,110,134 describes
an emulsion type explosive composition devoid of any self
explosive ingredient and ovntaining a closed-cell void-
containing material as a density controller.
While all of the aforementioned compositions are
meritorious, they are not without some disadvantages. The
composition of Bluhm, for example, is only suitable for use
in large diameter charges and requires strong primer initia-
tion. The compositionsof Cattermole et al. and Wade, while
useful in small diameter charges, require the use of expensive
xaw materials, demand extra handling precautions because of
the sensitive nature of the ingredients used and hence lead
to increase costs. All these compositions, includiny that of
Wade ~United States patent No. 4,110,134) tend to become dry
and hard upon aging due to the coalescence of the micro-
droplets of the salt solution. Without the addition of sen-
sitive perchlorate salt or self-explosives; cap sensitivity
can not be expected to be retained for any appreciable period.
It has now been found that all of the aforementioned
disadvantages can be overcome The present invention pro-
vides an improved small-diameter, water-in-oil emulsion
explosive composition which, even when devoid of any sensi-
tive self-explosive or perchlorate salt ingredient, is sensi-
tive to detonation by means of an ordinary blasting cap, even
at densities greater than 1 10 g/cm3, After storage for
extended period of time, the composition remains detonator-
sensitive and does not show any sign of deterioration. The
improved composition of the invention comprises an aqueous
solution of inorganic oxygen-supplying salt as the disconti-
nuous phase, an insolublel liqueiable carbonaceous fuel as
the continuous phase, occluded gas bubbles or gas-containing
material, and a water-in-oil type emu~sifying agent which
is ablock or graft copolymer of the type (A-COO)m-B, where
m = 2, where A i9 the residue of an oil-soluble complex mono-
carboxylic acid of mol wt. at least 500 and B i9 the residue
of a polyalkylene glycol of mol wt. at least 500 in combina-
tion with conventional monomeric water-in-oil emulsifying
agents.
More particularly, the block or graft copQlymer
emulsifiers suitable for use in admixture with a conventional
monomeric emulsifier in water-in-oil emulsion explosives has
the general foxmula (A-COO)m-B, wherein m is 2, wherein each
polymeric component A has a molecular weight of at least 500
and is the residue of an oil-soluble complex monocarboxylic
acid having the general structural formula:
. _
, Rl
R-CO -O-C-(R2)n-CO -O-C-(R2)n -COOH (I)
H P H
in which
R is hydrogen or a monovalent hydrocarbon or
substituted hydrocarbon group;
Rl is hydrogen or a monovalent Cl to C24
hydrocarbon group;
R2 is a divalent Cl to C24 hydrocarbon group;
n is zero or l;
p is an integer fxom zero up to 200;
and wherein each polymeric component B has a molecular
weight of at least 500 and is the divalent residue of a water-
soluble polyalkylene glycol having the geIleral formula:_
. R ~s
H - -0-C-CH2 - -O C-CH20H ( I I
H H
in which
R3 is hydrogen or a Cl to C3 alkyl group;
q i~ an integer from 10 up to 500.
The units of the formula
Rl
- O -C- (R2)n- CO -
H
which are present in the molecule of the complex monocarboxylic
acid as represented by formula I may all be the same or they
may be different in respect of Rl, R2 and n~ Similarly,
the units of the formula
R3
- 0 -- C - CH2
H
which are present in the polyalkylene glycol as represented
by formula II may all be the same or they may be different
in respect of R3.
-- 4
9~
The complex monocarboxylic acid, from which the poly-
meric components A are derived by the notional removal of the
hydrogen on the terminal carboxyl group, is structurally the
product of interesterification of one or more monohydroxy-
monocarboxylic acids together with a monocarboxylic acid free
from hydroxyl groups which acts as a chain terminator The
hydrocarbon chains R, Rl and R2 may be linear or branched.
R is preferably an alkyl group containing up to 25 carbon atoms,
for example a straight-chain C17H3s-group derived from stearic
acid. Rl is preferably a straight-chain alkyl group, and R2
is preferably a straight-chain alkylene gxoup, for example,
the unit ~ontaining Rl and R2 may be derived from 12-~hydroxy-
stearic acid.
The polyalkylene glycol of the formula II, from which
the polymeric component B is derived by the notional removal
of the two terminal hydroxyl groups, may be, for example, a
polyethylene glycol, a polypropylene glycol, a mixed poly(ethyl-
ene-propylene) glycol or a mixed poly(ethylene-butylene) glycol,
but preferahly a polyethylene glycol
Preferably each of the polymeric components A has
a molecular weight of at least 1000 (by "molecular weight" is
meant number average molecular weight). Thus where, for example,
the group R is derived from stearic acid and the unit containing
Rl and R2 together is derived from 12-hydroxy-stearic, p will
have a value of at least 2 Similarly, it is preferred that
the polymeric component B has a molecular weight of at least
1000. Thus where that component is the residue of a polyalkylene
glycol which is derived from ethylene oxide exclusively, q will
preferably have a value of at least 23
For optimum results for purposes of the present
-- 5
~.3L3~9~l06
invention the proportion of polymeric component B in the
copolymer is between about 20% to 40%, preferably 25% to 35%
by weight of the total copolymer.
The conventional monomeric water-in-oil emulsifying
agents with which the copolymeric emulsifier are combined
are, for example, sorbitan mono-oleate, sorbitan sesqui-oleate,
mono and diglycerides of fat-forming faltty acids or mixtures
o these. It has also been found that a portion of the mono-
meric water-in-oil emulsifier may be replaced with a plant
lecithin such as a technical grade soybean lecithin. While
plant lecithin is not suitable for use by itself in the present
explosive composition, its combination in amounts up to 60%
by weight with conventional monomeric water-in-oil emulsifier
provides the same emulsifying action as does the monomeric
emulsifier when used aloneO
It has been surprisingly discovered that use of
the copolymeric emulsifiers in combination with a conventional
monomeric emulsifier in an explosive composition of the type
described, even in small quantities, substantialLy expedites
the dispersion and emulsification of the aqueous phase. It
has also been found that the need to employ a high shear mixing
apparatus, required heretofore in the manufacture of detonator-
sensitive water-in-oil emulsion explosives containing only
conventional monomeric emulsifiers, is unnecessary when the
copolymeric emulsifiers are use~.
The following examples and tables demonstrate the
utility of the present invention.
EXAMPLE 1
A series of four water-in-oil emulsion e~plosive
compositions was prepared from water, inorganic oxygen-
; - 6
~3~
supplying salts, liquefiable carbonaceous fuels and emulsi-
fiers. The method of preparation comprised heating together
the liquefiable carbonaceous fuel (wax), hydrocarbon oil,
and emulsifiers at a temperature of from 60C to 85C until
the wax and copolymeric emulsifier ing:redients were liquefied.
A separate aqueous solution of inorganic oxygen-supplying
salts and sodium borate buffer was prepared at a temperature
of from 60C to 85C and mixed into the fuel/e~ulsifiers
solution to form a water-in-oil emulsion. Hollow glass micro-
spheres were then mlxed into the emulsion to form the finalcomposition.
The ingredients of the composition as well a~
the density and sensitivity of the final mixtures are shown
in Table I, below, the quantities shown being in percent by
weight.
- ~
m
r~
X ~i ~ o ~ :~
__
_ .
~ ~ ~ _l
o ~ ~ O ~ ~ ~ ~ ~ ~n
X ~I ~g o ~ o ~ i + ~
.... _
~ o
~ ~ O,~ ~ ~
H I ~ ~i 0 0 r~i ~ t~ t~l ~1 0 It- Lf) O IJ
.~ h ~IS
~3 1 , , ..... _ 1~ ~
_I 1:: ~ h
O ~ 1 1~ 0 ~ ~ O
E~ I Z ,,,,, " I, . - - ~ E4
,I~DO~o,l ~ ,lo~n~n O la
~ ~ 1 + ~ a~ u '~ ~
_ _ _ _ . ~ O ~ ~
~ U ~P
al a~ ~ o h U ~ o
U~ 4 J ~ ~ h ~ ~ ~7 3~ tS
.IJ ~rl O_ O ~J ~ ~ ~ ~
h ~ a~ ~ g10 ~ p, U U ~ o ~r~l ~rl ~ Id U
~ o ~ " ~ o ~ ,~
h ~ oU E; tJ~ O ~3 h tJ~ ~, U O ,~ U
H ~ C ) t~
c~ 1 ,Q O t~ ~ W ta ~ ~ 1 ,~
~1 Ll Ll Ei h Ll 1~ _I C`l ~) d'
E~ O O ~ O O O ~ 11
)
-- 8
~3C~
From the results in Table I it is seen that
Mix No. 4 containing no polymeric emulsifier failed initia-
tion while Mix Nos. 1, 2 and 3 were sensitive to cap initia-
tion,
EXAMPLE 2
A further series of water-in-oil emulsion explosives
; was made in a manner similar to that d~escribed in Example 1
and various copolymer emulsifiexs were added to separate
mixes. An amount of plant lecithin was also included.
The sensLtivity of the separate mixes was determined after
periods of storage, The results are shown in Table II below,
the quantities shown being in percent by weight.
~l3~
o o
U t~
,. .. .
a) (D a~
,, ~ ,,
.Y
,, ,~
. . I ~ ~ ~
_,
. o o
pi,
a~
_, l ,
O ~D ~ In ~9 ~ ~1` r~ o
Z; , ....... ..... ~
_~ ~9 o ~ o o ~ ~ ~ o o o
~ ~ U~
h h ~1
~ _ .
~ Id ld
~D ~
. O O O
o t~ s) 1~ o ~ a
.......... . ~
~1 ~ O ~ I O I O O ~ c~ ~ ~ ~5 ~
H I X ~9 ~I r-l "~ ,1 ~1
H I .,1 tQ u~ tl
l :~ ~
1~1 1 h h h
~ I _ _ _ _ _ m :n m
a~ I ~ ~ ~
I L(~
~o ~ ~
E~ I . O O o o
o ~ o ~ ~U~
- O
_I ~ o ~ o I I o o ~ ~ ~ o o o
X ~ ~l U IU . U
.~ UO UO UO
rl Orl O rl O
_ h C~1~ ~ h
O ~O ~ O
a~
,, ~" ~ ~ a)a
h h ~1 Id ~ 3
a) ~) a) a~ In O U~
,1~
4~ ~ ~ o a~
a) ~1 ~1 rl I S~~--I ~--I ~ ~1
tq ~q 0~rl a)
~ ~ rl C~ U rl U
ta S~ l
~) ~ ~1 X tn
rl h ~ O ~ Q h O h Q
(U ~ rl O ~ P~
.,1 rl O U U U U U
R rl rl rl ~ rlO ~1 0 ~1 O ~
o ~Sh h h (~) ~1 rl ~1 E3 C) oO O C~ O
~-I ~ 1 0 ~ ~ 4
tr~ 1~3 h E! ~3 E3 rl 1) ~ ~ u~
_
~ O O ~ O O O O ~I td ~ ~1
__
-- 10
~3
_ ~
o o
,,
X ,i o u~
.
.
Zj~ ~~ o
~J X ,~ o u~
H I _ _
H I U')
~1 ~Z;' O ~ ~1
~ r-~ O IS) lf~
lC~ I .~ t~
~ h:::
_~ O
U~
~ U U ~ '~ E03
a) u
a)
~ ~ :-
1-1 rl ~I h 0 ~3 ~ 0
_ O C~
1 '1
From the results in Table II it is seen that
a range of polymeric emulsifier types may be employed and
in each instance sensitivity to cap initiation was retained
even after extended storage,
EXAMPLE 3
A further series of water-in-oil emulsion explosi-
ves was made in a manner similar to that described in Example 1
and varying amounts of polymeric emulsifier/conventional emul-
sifier and plant lecithin blends were added to the separate
mixes~ The sensitivity of the separate mixes was determined
after periods of storage. The results are shown in Table III,
the quantities shown being in percent by weight.
- L2
~ 13~
_ -- ~o
. . ~
o ~
,~ a~
,
. ~ \\\\\
O ~ n 1~ r` O ~ ~1 ~ d' h E4 1:4 ~ E4 .-
Z .......... ~ ................ I
~ ~ o ~ o o o ~ ~ ~ ~ o u~ ~ ~ o o X
X ~ .
.
0
_ _ a~
.
. O ~ \ o
~o I` ~ In ~ o ~ ~ o ~ E4 ~ 4 u
o ~ o o o ~ ~ ~ ~i o u~ ~ ~
X ~ ,a~ .
. _._ ~
O
H I a~
H I ~ I
H ICO ~:5
. ~ \\~\~ 10
O d' 1~ D ~ O t` I` O ~ r-l O d' ~ ¢~ 4
I~Z. - . . ~ ., .,, , ., 5-
~1 ~ O ~ O .~ O ~ ~ ~.~ ~ Lf) Ln t` ~` ~ ~ ~ C~
I X ~
.,~ m
m I
_ ~
V
~ o
.,, o
h ~
h ~ ~ o: _ ~1 3
O
~ S~ ~ 5
a~ ~-- O ~
~n ~ ~ c) ~ ~ ~ ~1
o ~ ~ _
~: h ~ O1 ~ ~ U U ~-- rl O rl U
CJ ~ ~ l X u~ U ~ r~ ~ Ei u~ o
.~ rl ~ d O \ ~ 1
~1 ~ ) h u~ ~1 0 ~: h tJi --l h ~ 9 h O
a) ~1 o u u u ~ rl ~ E3
h E3 ~ R ~ ,1: h 1::
h td ~l rl ~l Ei ~ ~ n) E3 U~ ~D 0 ~1
~r~ - - - - c~ o
H ~ a) e s~ ~
o~
F~1 h ~ h h d ~ ~ h El ~ ,_
E~ O O 1~l 0 0 ~ ~ 1 a) X (~ 1 -1
~ Q, O C~ ~ ~
13
~iL3~
From the results in Table III it i5 seen that
various amounts of polymeric and monomeric emulsifiers may
be employed while retaining long storage sensitivity of the
explosive compositions.
EXAMPLE 4
A ~urther series of water~in-oil emulsion explosive
compositions was made in a manner similar to that described
in Example 1. A combination of polymeric and monomeric emul-
sifiers together with plant lecithin was employed~ In one
case no polymeric emulsifier was used. The sensitivity of
the mixes was tested after extended storage, the re~iults
being shown in Table IV, From ~able IV it can be noted that
Mix ~o. 12, devoid of the polyme~ic emulsi~ier, failed to
initiate with an E.B. cap after three months storage while
Mixes 11 and 13 retained sensitivity.
- 14
~3~
. ~ .... ~
~1 a)
. U~
o ~ I~ ~ ~ ~ CO ~ _~
...... . .. o ...
o ~ o o o, ~ ~ ~ ,, o Ln U~
X ~ +~
_ . _ _ _ ~,
o
,' o ,~
O o ~ u~ ul r~l t~ u~ ~1 U) ~ r-l ~ d'
~: .. , . . ..... ...
0~0~ 1 ~ oo~,~ ~ou~u~ ,~
XUl ~1 ~1 +
~ O
_ ~ , _
~1 ~,~
O ~ d' ~ ~ d'
I ~i ...... ..... ...
~ g o ~ o o o o ~7 ~1 ~ r-l O In Ln
~ I X Ll~ ~:~
E l I ~ N O O
~'1
0
,U ,~ ,
h sd .. 1 ~ ~ h
a~ o ~ ~ a~
I O U~ ~ ~ O ~1
o ~ ~ o o
rl
~ Lg~r~ u
D~ ~ o ~ ~ ~
s~ ~ U U ~-- .,~ O U,
~ ~ ~ I X u~ U ~rl la
0 rl h n~ ~ O rl 1~ U ~ (~ ~ ~J ~-1 ~1 rl
.~ ~ ~ 5~u~,1 1` O 3 5~ h O la
~1 0 U U U --~ O :1 ~ U _
al E~ ~ ~ E~
o ,~ ~l e ~ ~ ~ o,
e a
u
H o~ t5~
~ 1 h ~ ,_ ~
e o o ~ o o ~ 3 X ~ a~ ~ r~
_ ~ a o
._
~, ~
I J
- - ~ -
~m m m ~
oo o ~ ~ ~
X ~ 1 o
.
_l m
~ ~m~
~ COCO~
_
o ~I
: ~ l _~
H I O ~ ~O
~ ~ Zi E~ m m _1
~: I ~ ~ t
_ _
.
.
U~ fd :~
~ .
~ ~ ~o
H . .
'1 ~
~3~
The ratio of the polymeric emulsifier to the
conventional water-in-oil monomeric emulsifier (including
lecithin) is preferably in the range of 1:6 to 1:2. The total
amount of emulsifier (polymeric plus monomeric plus lecithin
when used) found suitable for use in from 0~8% to 2~5%,
preferably 1 2% to 2% by weight of the ~otal explosive com-
position.
The emulsion explosive composition of the invention
may be made using conventional mixing apparatus normally used
in the preparation of aqueous slurry explosive manufacturing
processes. The use of high shear mixing apparatus ha been
found to be unnecessary
In preparation, the carbonaceous fuel and mixed
emulsifiers are first added to the mixer bowl and heated to
a temperature of from 60C to 85C until liquefaction is
achieved. A solution of oxidizer salt, water and any buffering
agent is separately prepared and added to the liquefied fuel
in the mixer at a temperature of from 60C to 85C. Mixing
is continued until a viscous water-in-oil emulsition is formed.
Where the inorganic salt used contains additives such as anti-
caking materials and the like, the solution of oxidizer salt
is preferably filtered before addition to the liquefied fuel
in order to remove any insoluble matter which may be present.
Such insoluble matter has been noted to adversely affect the
emulsification and stability of the final composition. During
cooling, air is whipped into the mixture by further agitation
or in-situ gas-generating reagents arP dispersed therein.
Air-containing particulate material such as glass microspheres,
if used, can also be added at any time after the emulsion is
formed. The amount of gas or air-containing particulate
material employed will be sufficient to maintain the density
of the composition between 1.00 and 1.35 grams/cc. After
mixing, the product may be cartridged or carried to the
blasting site and pumped directly in boreholes.
The preferred inorganic oxygen-supplying salt
suitable for u~e in the improved explosive composition
of the invention is ammonium nitrate; however a portion
of the ammonium nitrate may be replaced by other inorganic
oxygen-supplying salts such as sodium nitrate, calcium nitrate
~0 and potassium nitrate.
Suitable water-immiscible emulsifiable fuels for
u~e in the composition include petroleum oils such as ~o. 2
uel oil, paraffin oil, mineral oil and vegetable o;ils.
Liquefiable waxes such as paraffin waxes, microcrystalline
waxes and mineral waxes are also suitable fuels. Particularly
preferred i9 a mixture of paraffin wax and paraffin oil of
medium viscosity in order to pro~ide good stability
The quantity of oxygen-supplying salt used in the
composition may range from 55% to 85% by weight. The amount
of liquid or li~uefiable carbonaceous fuel may be used in an
amount of from 2% to 10% by weight Water in an amount of
from 10% to 25% is suitable. A preferred composition comprises
75% to 83% by weight of oxidizing salts, 10% to 16% by weight
of water, 3% to 6% by weight of liquefiable fuel, 1.2% to
2.0% by weight of mixed emulsifiers and up to 1% by weight of
an emulsification promoter.
The present invention thus provides a composition
detonable in small diameter charges without the aid of any
booster or primer. Because of composition is devoid of any
self-explosive or ~ther sensitive material, it may be manu-
- 18
~3~
factured safely and at low cost and stored and shipped with
minimum risk, and unlike the water-in-oil emulsion explosive
compositions of the prior art, the composition may be stored
for unusually long periods without significant loss of sensi
tivity. The composition lends itself to preparation in the
explosive factory where it may be packaged for use or it may
be prepared at the blasting site in a mobile mixing facility.
-- 19
