Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to the combination of a pesti-
cide and a solid oxidant in a package. The pesticide comprises
a compound having a toxic, active ingredient which releases
phosphine upon contact with moisture. Typical o~ such active
compounds are aluminum phosphide and magnesium phosphide.
; The solid oxidant comprises a substance or mixture o~ sub-
stances which decompose with water the metal phosphide or
residue remaining after the development of phosphine during
processing. m e oxidant oxidizes into harmless compounds
the phosphine (hydrogen phosphide) which may ~orm. The pack-
age is permeable by gases such as air, water vapor or phosphine.
A ~orm o~ a combined administration o~ pesticides and
oxidants is described ln German patent 2 206 487 and 2 206 494.
These references disclose a sheathing or envelope consisting
o~ a durable film~which is wholly or partially permeable by
gas, resistant to mechanical stress and provided with recesses.
Some~of the recesses house the oxidant, while the other
recesses house the;pesticide. The recesses are covered by a
substance, such as Japan~Paper, which is permeable by atmos-
pheric moisture. I* use, these packages are placed in a
~horizontal position in an area to be ~umigated. The side
permeable by a gas ~aces upward.
German patent 698 721 discloses a process for exterminating
grain pests.~ According to this patent, paper bags containing
phosphides are deposited ~or several days in the ~rain storage
~; space. After the grain has been treated, the bags containing
the remainder o~ the pesticide are removed from the storage
space. No special instructions are given ~or destruction o~
the residue w~ich accumulates during treatment; in particular,
no provision has been made in this case ~or the inclusion in
the paper bag of substances, such as solid oxidants~ ot~er
than the phosphide.
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~037~7
Ge~man patent 709 748 describes another process for
- fumigation with p~osphine. In this case, a phosphide and a
water-releasing salt containing water of crystallization are
enclosed by a gas-permeable envelope of, for example, unsized
paper The resulting package is introduced into the space
to be fumigated or deposited in the stored grain. The pro-
portion of the water-releasing salt relative t0 the phosphide must
be regulated in such a way that complete decomposition of the
phosphide is assured within the required time.
A phosphide packed in paper bags does indeed represent
a well acting pesticide ror the treatment of grain and simi-
lar bulk goods, since the bags can be deposited deeply into
the material to be treated where the desired development o~
phosphine is a~sured. After the treatment of the goods,
the bags containing residues can be removed easily without
contamination of the treated goods. Neverthelèss, there are
~ ~ diffLculties ln the safe destruction of the fumigant resi-,~; dues, particularly~in view of the increased emphasis on
~prese~rvation~of the environment. Where there ls only a gradual
~;20 ~ admission of moisture to the phosphide during the fumigation
~operation, a~complete decomposition of the phosphide is not
guaranteed. ~Hi~therto, it was customary to bury or burn the
bags containing the fumigant residues. These methods for thè
disposal of toxic resid~es are not entirely satisfactory.
,,.,
For example~ burying of fumigant resldues ha~ been prohibited
in some countries because of the dangers involved. On the
other hand, if the bags containing the fumigant residue are
placed ln running water, then an aqueous solution containing
l phosphine can res~lt. Disposal of such an aqu~ous solution
; ~ 30 raises new problems. ~
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It is the task of the present invention to provide a
package for the administration of a phosphide-containing `
pesticide, which upon contact with water results in the
quick, safe and substantially complete conversion of the
fumigant residue so that the phosphine concentration in the
resulting aqueous solution does not exceed about 0.01 ppm.
Accordingly, this invention provides a packaged pesti-
;;; cide comprising a phosphine-releasing metal phosphide and a
solid oxidant in a gas permeable package. The package
10 comprises a container having a closure, which opens quickly `! '
upon contact with running water. The closure comprises a
minor proportion of the area of the surface of the package.
According to this invention, such natural or synthetic
polymers are employed as the material for the closure, which
i" 15 are durable and stable in the absencQ of running water, but
. ., ::
which decompose quickly andtor dissolve ~uickly upon contact ~ ,
with water. Well sulted for use in this invention are ~
closing materials which decompose and/or dissolve within ~`
..... .....
thirty minutes of being contacted with water. Particularly
preferred are sealing materials which dissolve and/or
decompose within about twelve minutes after contact with
water.
.,, ~ ~ ..... .
Typical of the synthetic polymers which can be employed
as closing or sealing materials are polyacrylamides having
25 recurring units of the following formula: j,
¦ R3
f ~;
~ Rl
... _ _ ~.`.,.:"','.'.'`"',
., ~ ....
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; Wherein Rl signifies a methyl radical and R2 and R3'signify
"' hydrogen; o~ in which Rl is hydrogen~ ~ is hydrogen and R3
,, is hydrogen or a methyl radical. Other materials include
, polyethyleneoxides having ~olecular weights above about lOO,OOO;
, 5 polyvinyl alcohol; atactic polyvinylmethylether; polyrJinyl
pyrrolidone; copolymers o~ ~inyl acetate and vinyl pyrrolidone
, (about 60 p~rts vinyl py,rrolidone ~or each 40 parts of vinyl
,, acetate-); copolymers of poly~Jinyl alcohol, polyvinyl acetate
",, and polyethylene oxide (in a weight ratio of 50: about 20:
,~; lO about 20). Typical of the natural polymers are alginates,
" cellulose ethers, dextrine, and gelatin. Particularly pre~erred
,,;, sealing materiflls are polyvinyl alcohol and polyethylene oxide.
,, In a preferred embodiment of this invention. the con-
~ tainer is ~illed with the pesticide and oxidant~ and i8 closed
',, 15 by sewing it with a thread ~hich is decomposable or soluble
in water and comprlsed of a natural or synthetic polymer of
the type enumerated above. Particularly well suited for this
~purpose is a thread comprised of polyvinyl alcohol and having
,r~ a diameter of~ about 0.2 to about 1.8 mm. It ~rill be under-
20~ stood that threads~having larger diameters can also be employed
in other 6ituations.
In a further preferred embodiment of this invention,
the container~is filled with the pesticide and o~idant,, and
an insert of~natural or synthetic polymers decomposaible and/
or soluble in water is placed between each open section o~
~ the Pilled container in order to close it. l'he insert is
then sealed to the contalner by the application of heat and/or
pressure.
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:~ ~ 79~27
In another preferred embodiment, the closure comprises
a cap which is adhesively secured or sealed tightly to the
material of the container~ and the c~osure in this case com-
prises one of the a~orementioned natural or synthetic polymers.
: 5 In a particularly preferred embodiment, the cap conslsts
essentially of a polyvinyl alcohol ~ilm. With such a cap the
bag, after being charged with pesticide and oxidant, can be
; closed. A strip of the film can be applied along the longi-
tudinal edge o~ the narrow side of the empty container in
the area of the opening. The movable portion of the film
can be folded back over the opening o~ the bag and sealed
along the second longitldinal edge to the other wall o~ the
container by the application o~ heat and pressure.
According to the present invention, the package for
~ 15 the pesiticides and solid oxidants comprises a container
.. , having a closure which opens quickly upon contact with water.
s~ ~ Quick opening of~ the~container and the quick admission o~
~rater~into the container~can~be accelerated by holding the
bag materlal unde~r a latent~tension in the area o~ the
j ~`20~ opening~by means~of some pretreatment or by m~ans of a
s~ ~permanently~elastLc material connected thereto. When the
tenslon i9 released by the dissolution and/or decompositlon
of the closing materlal~ at least a partial spreading o~
the opening o~ the co~tainer occursJ and results in an scceler-
ated admission of water into the container. To accomplish
t~hls result~ the bag material can be provided with permanent
corrugations ln the area o~ the opening~ perhaps b~ the appli-
cation o~ heat or steam in a press, and optionally wlth the
use o~ chemical additives to aid in the ~ormation o~ suc~
3 corrugations. Upon closing o~ the container, ~or example by
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` ~37~;~7 ~:
sewin~ it together with a thread which dissolves or decom~
poses uoon contact with water, the edges of the bag are
fitted smoothly against one another, but remain under latent
tension, which leads to at least a partial spreading of the
opening of the bag after elimination of the closing material. ~-
In another alternative, one or more thin wires comprised of `
a permanently elastic material can be threaded into the con- ;
tainer material in the area of the opening. The elastic
material is in tension which causes the opening of the con-
tainer to spread after dissolution and/or decomposition of
the closing material. In a further embodiment, one or more
!.`"' permanently elastic threads comprised of natural rubber, -~
synthetic rubber or polyurethane elastomers are provided for ~`
this purpose in the area of the opening of the filled con~
tainer. Such threads are attached merely in the area of
i the two longitudinal edges of the material of the container,
` and are under such tension that they will effect an at least
:,; , ...
~; partial spreading open of the bag after dissolution and/or
; decomposition of the closing material.
It is essential in this invention that the closure,
which dissolves and/or decomposes upon contact with water, .
comprise only a minor portion of the circumference of the
container or a minor area of the total surface of the con~
tainer. In the case of alI the examples, the phosphine con- `
centration in the water used for~elimination of the residues
did not exceed 0.01 ppm; such water can be safely added to
; ; i
i~ customary sewa~e.
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Within the scope of the present invention, the pesticide
and solid oxidant are placed together in a container. Sur-
prisingly, it was observed that in bags which consist of
a material that is normally readily permeable by water, `~
. 5 water will infiltrate only very slowly after fumigation.
Without being bound by the following explanation, it is
assumed that in the case of gradual hydrolysis of metal
phosphides, the residue accumulates and obstructs the pores `
of the bag material and/or reacts with the water first
entering the bag in such a way that further admission of
water is greatly delayed or completely prevented. As demon- `
strated in the;following examples, the closure of this in~
vention made of natural or synthetic polymers which decompose ;;
. ;, ,~,. : ,,
and/or dissolve upon contact with running water, provides
for the improved elimination of pesticide residue according
to the task of the invention, even i~ such materials are ; ~i
employed for bags which per se are readily permeable by
; running water.
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~; The container employed in this invention preferably
comprises a gas-permeable, flame retardant, tear-proof fabric,
such as for example, flber fleece or textile fabrics. The
container material can be easily permeable by running water;
by~this~ lt is~meant~that l -cm of such a fabrlc is~penetrated
by~at least one~m~l oP~water within 100 seconds under a pressure ;;~
~of 10 cm water column.; Preferably, the fabrics are com-
prised of polyvlnyl chloride having a weight per unit area
of 240 to about 400 g/m2.
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By a PVC ~abric we understand a ~abric which consists
predominantly of polyvinyl chloride, PVC-mixed fabrics
comprising at least about 70 weight percent polyvinyl chloride
- can also be employed.
- 5 Wlthin the scope of the present invention, tear-proof
fabrics are used as t~e mAterial for the bag. Suitable fabrics
, have a tear strength at least about 4 kg/cm both in their
;.~ dry and in their w~ a~ state.
Although the shape of the container is without any
;~-, 10 essential importance in view o~ the setting o~ the problem
according to the invention, preferably the container is a
,~ bag. Preferred are bags which are obtained ~rom two slmilar
rectangular pieces of material having a width o~ about 4 to
about 12 cm and a length of about 6 to about 20 cm. Hose-
15 shaped material having a diameter of about 3 to about 10 cm
is particularly preferred. The hose-shaped material can be
cut to the deeired length and closed at the open ends.
The pesticide employed in this invention contains as
its active7~toxic ingredLent a compound which releases phos-
`~; 20 ~ `phine~(PH3)~upon~c~ontact with~moisture. Typical of such
~phosphides are inorganic metal phosphides~ such as calcium
; - phosphide, magnesium ph~osphide and aluminum phosphide. The
individual phosphide particles can be provided with a pro-
tective coating to control the admission Q:~ moisture. Typical
coating materials are para~in~ metal stearate, polyethylene
oxide or wax like polyethylene glycols. In addition to the
metal phosphides, one can also employ inert diluents (silicon
dioxide, aluminum oxlde and clays), substance~ which release
a gas at moderately increased temperature (ammonium carbamate,
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37~2~7 `.:
ammonium ~arbo~ate a~d sodium blcarbo~ate~ ~trong~ solld
bases (sodium oxide~ ~odium'hydrox~de and po~asslum hydroxlde~
,",,~ detergent~ (~lkyl sul~n~te~. ~lkyl~ryl ~ul~on~tes)p
:, compressing aides (ta'lcum~ and other additives~ The~e, ~ddl- ~
, 5 tives can be within the protective coating ~or the metal "
," phosphide~ Well suited, for example, i8 a composition sold ,~ ;
,~ by the firm DEGESCH, Frankfurt, (West Germany) under the '';''"
,,~ I trademark "Phostoxin". The ingredient releasing the r. ''.
; phosphine can be in the form of a powder~ a fairly coarse ~,
!~'",~ 10 granulate or a pre~orm, pressed obJect. Depending upon size~ "each contal~er will generally contain about 10 to about 100
,,, g phosphine as~active ingredient. ~ ;~
,' An important aspect o~ the present invention,involves `,,
the Joint packing of the solid oxidant in the container
,~, 15 with the phosphlne-releasing actlve, toxic ingredient. The
solid oxidant consists of a!substance o~ ixture of substanees
.l , which in~ures the quick and co~.plete conversion oP the pesti-
cide~ residues~lnto harmless products when the residues are
contacted ~Jith water. 'l~en a mixture o~ substances is employed~ ' ,~
the mixture i8 C omprlsed mainly of the actual oxidant, andcan
" include a material which will adapt ~he pH o~ ~he water to ,
the oxidant. In order to assure a quick reaction in water, ~,,
.~ water soluble substances and mixtures oP substances can be ` ;~
"~,l employed, Mixtures oP calcium hypochlorite and citric acid ~
in a weight ratio of about 1:1 have proven succe~sful. ~ '
,,, Potassium permanganate and sodium oxide in a weight ratio of
~ about 40:1 can also be employed. Other suitable oxidants
"~"I include mixtures of sodium perborate or potasslum permanganate
,~ ~lith citric acid or sodium percarbonate with manganese salts.
~,l 30 Chromium (VI) oxide iL particularly prePerred. The mixture ~
of substances can also contain'a redox indlcator. The quan- ~ ,
~,i tity o~ mixture oP subst~nce~ having an oxidizing e~fect ` ,'~
.
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~37~7
..
; depends essentially on the quantity of phosphine-releasing,
"4,' active ingredient; a ratio of about 0.2 to about 0.5 parts
by weight by oxidizing substance to one par~ by weight
.; phosphine-releaqing active ingredient has proven success~ul.
In order to prevent any reaction between the toxic,
active ingredient and the solid oxidant before or during the
actual use of the~pesticide for ~umigation, the oxidant can
be encased ln a separate envelope made of an inert material,
soluble and/or decomposable in water. For this purpose, a
. 10 sheathing o~ polyvinyl alcohol or waxl.tko polyethylene glycol
i8 particularly sultable. At the same tlme, individual
~j particles, granulates or molded article~ o~ the oxidant can
be coated, ~or example, with polyethylene glycol. In the
: alternative~ the entire quantity o~ oxidant can be within the
~;l 15 inert, water soluble envelope, ~or example inside a c~osed
small bag of~ polyvinyl alcohol or polyethylene~glycol ~ilm.
~ ~ ~Chromium~VI)~ oxide iD~a small bag of 0.1 mm thick polyvinyl
s~ ~alcohol film~has proven to be a particularly quick and safe
: ; : ~ .
~ acting oxidant;~e~en in the case of a storage time o~ more
. . 1 . ~, ~ ~
~ ~ than twelve months, there occurred neither a destruction o~
~the small bag, nor~any reaction of the Chromium (VI) oxide
with the phosphine-releasing actlve ingredlent. The e~ective-
ness o~ the Chromium (VI) oxide also remained unchanged.
Based~on present experience~ the best ~orm ~or admini-
~l 25 stering the phosphide-containing pesticide and solid oxidant
~ 1 .
in a ~oint packing according to this invention consists o~
.l about 10 to about 100 g "Phostoxin" with about 3 to about 30 g
Chromium (VI) oxide in a separate~ tight shaathing o~ 0.1 mm
thick polyvinyl alcohol ~ilm. Both components are in a bag
:
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37 gL~:7
- made of a flame retardan~, tear-resistant PVC fabric readily ~
permeable by steam or running water (weight per unit area ~ ~-
about 320 g/m2) having measurements of 8.8 x 14 cm. Pro-
vided in the area of the opening between the two lateral
;- 5 parts of the bag are two threads of urethane elastomer under
- tension. The bag is closed with a seam formed by a 0.8 mm
thick thread of polyvinyl alcohol. ~
; This invention will be more fully understood by refer- ^
. ,. ,. ~,, , , -
ence to the following examples. `~
Example 1
Rectangular pieces of 31 x 10.5 cm are cut from a PVC
fabric having a weight per unit area of 322 g/m2, which is pen- ;
~ etrated within about 4 to 6 seconds by l ml running water per
;;, l cm of fabric under a pressure of a 10 cm water column. The ;~
; 15 pieces are placed on top of one another each ;time in double `
~ layers, and are sewn together with a PVC thread along the two
.. . .
longitudinal sides. The little bag obtained is turned and
~, filled with 40 g phostoxin powder ("Phostoxin" is a trade mark
for a powder containing aluminum phospide as a phosphine-releasing `~
~0 metal ~hosphide,and aluminum oxide and ammonium carbamate and ;~;
a coating of paraffin). 16 g Chromium (VI) oxide are added
in a small, closed bag of 0.1 mm thick polyvinyl alcohol film.
'~ Subsequently, the~bag is closed on the still open narrow side
by means of a seam formed by an 0.8 mm thick thread. ~;
Example 2
In the manner described in Example l, a bag is made of the
'l PVC fabric easily permeable by running water, and is filled
with the components listed there. For closing of the bag, a
` strip (8.8 x 0.5 cm) made of 0.6 mm thick polyethylene oxide
film is placed along the narrow side between the walls of said ,;
; ,il ~ .. ;,:
bag, and for the purpose of closing is guided through a film ~
sealing device. ` ;
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Example 3 ~37~27
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~; A bag is made in the manner described in Example 1
using the PVC fabric permeable by running water. Prior to ;
;` filling the bag, a strip ( 9 X 1 cm) made of 0.1 mm thick
polyvinyl alcohol film is sealed along the open narrow side
., :,, .
to the outside of one wall of the bag. After filling with
the components listed in Example 1, the sealed strip is
folded back over the opening of the bag, and is then also
sealed to the other wall of the bag.
Example 4
:: .
~i As skated in Example 1, a bag is made of PVC fabric
easily permeable by running water, with weight per unit area
of 322 g/m . The two pieces are sewed together so that the . .
seam will end along the two longitudinal sides in the area
of the opening of said bag just 1 cm before the actual edge.
;; After filling of the bag with 40 g "Phostoxin" powder
and 16 g separately enclosed Chromium (VI) oxide, the
opening of the bag, with sllghtly folded up lateral parts,
is moved over two urethane-elastomer threads, kept under
tension,~and these threads, while maintaining their tension
are sealed with;two~pieces of PVC fabric in the area of ~;
their two longitudinal~edges, and these two pieces of PVC ~
.. . ~ : . .
fabric are sealed together, too. Subsequently the still
~ open bag is closed by a seam of an 0.8 mm thick polyvinyl
; ~ 25 alcohol thread without interferring with the elastic threads.
~ The effectiveness of the form of administration accor-
;~ ding to the invention was examined with a view toward the
safe and complete elimination of pesticide residue.
Specifically, the time required for complete conversion of ;~
`~ 30 residue in water, and the quantity of phosphine occurring ~;
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. `;thereby in the water were determined. For purposes of com- ~ `
- parison, other packings for phosphide-containing pesticides ;;
.. ~ . ;.
were also tested~
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A. Bag of a PVC fabric, described in Example 1, ~
. 5 with contents as stated there; however, the ;
~. ~'.i.,.
bag was closed with conventional thread not dis~
solving or decomposing quickly in running water. '~
B. A joint form o administration for a phosphine- ;;
releasing, toxic, active ingredient and solid
oxidant as in the German patent application
: i.. -:
22 06 494.
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C. A paper bag as used in case of~a commercial ;`
; phosphine-releasing preparation (DETIA Ga~ B
- Trade Mark). The known bag was ~illed with
40 g "Phostoxin" powder and was closed again. C
, .
` D. The known paper bag, as stated in case of
sample C ~DETIA Gas Ex-B - Trade Mark)~ was filled
;~, with 40 g "Phostoxin" powder and 16 g Chromium
....
` (VI) oxide in a separate envelope made o poly- `
.~ . :,:
', 20 vinyl alcohol film, and was closed again.
s~ As a starting materlal for the examinations, residues in
the~above listed;samples were used which resulted after 120 ~;
hours~of fumigation o~f grain (the samples in each case were
inserted 35 cm deep~into loosely heaped up and subsequently `=~
covered up grain) under the same conditions. For the elimi-
` nation of the fumigation residues, the samples were added to ~ `~
.,., , ~ .
`~ 300 ml of water. ~They~were stirred in occasionally and sub-
.l merged, and the time up to the complete conversion of all
t¦~ phosphide residues~was determlned. After expiration o this
time period, the concentration of phosphine occurring inS the
water was also determined. The determination o the phosphine
content was accomplished essentially according to
.:, :, :, ~ .,
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~37~27
.. ~ the instructions by White and Bushey in J. Am. Chem. Soc. 66,
pp. 1666-72 (1944). The complete elimination of the
.. fumigation residues is accomplished when all phosphine
developing components h~ve been converted.
. ~ 5 The results of the experiments are presented in tl;e
. following table.
''`'':' . .
;~ TABLE
Elimination of the residues ~rom the forms o~ administration
.~ o~ phosphide containing pesticides~ according to the inven-
~ 10 tion (1 to 4) and partly ~nown (A to D)~ accumulated a~ter
i.~ their appllcation
. . . _ .
,i, Samples Time to complete Phosphine content
eliminatlon in the water used
1 70 to 180 min's below 0.01 ppm
; 15 2 ; ~80 to 220 min's below 0.01 ppm
3 ~ ~ 60 to 150 min's below 0.01 ppm
,........ .
4 ~ :50 to 140 min's below 0.01 ppm
.' ~ ~ A~ ~ 500 ~o 800 min's~ below 0.01 ppm
B ~: 3 to 450 min's below 0.01 ppm
:
~1, :20 C after l?o hrs no above 50 ppm
. complete conver-
',,',;',,1~: slon .
D a~ter 120 hrs no above 50 ppm
;.. , complete conver-
'~.'k~ 25 sion
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From the results of the experiments it is apparent that
under the stated conditions, the same for all samples, the
elimination of the resldue with the form of administration of
this invention requires conslderably less time than the eli-
mination of residue using kno~m forms. This is particularly
remarkable in view of the fact that the materials used ~or
the bags are really easily permeable by running water. It is
completely surprising that there is no analytically determinable
phosphine content in the water when packages of thls invention
are employed ~or the el~mination o~ pestlclde residues. Since
the complete elimination And/or complete convers~on o~ the
phosphide-containing pesticides into harmless products repre-
sents an essential aspect in case o~ use of such agents, the
l present invention does lead to a superior type o~ pesticide.
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