Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates to a tagging means,
specifically for the tagging of finely dispersed systems,
allowing an identification of the material used with res-
pect to its origin and its composition and, optionally,
with the aid of microanalytical methods, the date of its
production In other aspects, the invention relates to
the process for the production of such tagging means and
their use, specifically for the tagging of finely dispersed
substances.
The increase in thefts and illegal use of explosives
has led to the necessity of being able to offer clear proof
of the type and, optionally, of the date of production of
explosives. A number of tagging means have already been
proposed or put on the market. Tagging means for explosives
are described, for example in U.S. patents 4,053,4~3,
3,772,200; 3,897,28~, 4,131,064; 4,197,10~, ~,961,106;
3,967,9gO and 3,993,838. Canadian Patent Application S.~.
420,563 filed January 31, 1983, Wolfgang Weller et al,
describes further improved tagging means, which are ferro-
magnetic components as well as, optionally, fluorescent
pigments, soluble and insoluble fluorescent materials, colored
pigments, oxides and/or salts of rare earth elements as well
as oxides and~or only soluble salts of rare earths in micro-
analytically readily detectable quantities embedded in high
molecular, thermoplastically processible polymers produced by
the homogeneous melting of the components, granulation and
pulverization.
It has now been found that a widespread need for tagging
means exists not only for explosives but also for a number of
other substances. Finely dispersed systems, specifically finely
pulverized substances of high effectiveness or high value and,
--1-- ~s~
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specifically, of high quality standards, should be tagged in
such a way that it is possible to determine at a later date
whether they are the original substances. In a number of
instances, it is even desirable to be able later to deter-
mine, as in the case of explosives, not only the manufacturer,
but also the dates of production and packing. finely
pulverized substances of this type are, e.g., herbicides,
pesticides, fertilizers and even finely dispersed systems
such as high-quality special varnishes, etc.
The tagging means used for explosives are unsuit-
able for such purposes since they are too coarsely grained
and cannot, even with the aid of special technologies, such
as pulverization using liquid nitrogen or by solution/pre
cipitation processes, be dispersed with adequate fineness.
The plastics taught as tagging means for explosives, such as
polyethylenes, polypropylenes, polyamides, polycarbonates,
polyesters, polyoxymethylenes or acrylonitrile-butadiene-
styrene copolymers, cannot be pulverized even at extremely
low temperatures, e.g. under liquid nitrogen, to the desired
granulation magnitudes of less than 50 em, preferably less
than 20 em.
The problem to be solved is the making of tagging
means for finely dispersed systems, which can be both readily
and economically produced and pulverized to homogeneous
particles of less than 50 em in size and preferably smaller
than 20 em. The tagging means must also be resistant to water
and moisture, yet should be capable of being easily separated
from the finely powdered substances and of being unequivocally
identified by microanalysis.
It has now been found that the uncured polymer com-
ponents of powder varnishes having a polyacrylate, polyester
~z~
or polymer epoxide base are excellently suited for use as
materials which can be thermoplastically processed so as to
disperse and/or embed in their melt iron or ferromagnetic
alloy powder as well as the other substances easily identified
by microanalysis. The melt, containing the ore substances,
after cooling can be pulverized to particle sizes of less
than 50 em, preferably even to less than 20 em.
The tagging means of the present invention consists
essentially of a) at least 1 weight percent of iron or ferro-
magnetic alloy/powder, and microanalytically detectable
quantities of at least two of the following substances:
b) fluorescent pigments,
c) organic solvent soluble, water insoluble fluorescent
material,
d) colored pigment,
e) difficultly soluble oxide cr salt of a rare metal and
f) oxide or difficultly soluble salt of a rear earth;
homogeneously mixed in an uncured thermoplastic polyacrylate,
polyester or polymer epoxide base powder varnish.
In the process for the production of the tagging
means according to the invention, the polyacrylate, polyester
or polymer epoxide uncured powder varnish, a material capable
of being thermoplastically processed, is heated and substances
a) through f) are introduced into the resultant melt and homo-
geneously mixed, the mixture cooled and granulated, finely
pulverized and, optionally, the finer grains separated from
the coarser grained material by air classification.
The iron powder and/or powder of ferromagnetic alloy
must be present in quantities of at least 1%, so that the
tagging means can be extracted from the finely pulverized
substances with the help of magnets. As a general rule,
quantities of 3-20 weight percent of ferromagnetic material
are employed. Quantities of 5-12 weight percent have proven
to be particularly effective.
For unequivocal coding and decoding of the tagging
means according to the invention, at least two of the follow-
ing substances: fluorescent pigments, fluorescent materials,
colored pigments, oxides and/or salts of rare metals as well
as oxides and/or rare earth salts of very low solubility must
be present. The greater the number of substances used, the
greater is the variability and the greater the ease with which
an unequivocal determination of the producer, date and com-
position of the tagged material mixture can be made. To enable
good microanalysis of these substances in the tagging means
according to the invention, these should be present in the
following quantities:
b) fluorescent pigments, of from 0.1 to 8 weight percent,
preferably 2 to 5 weight percent,
c) fluore.scent materials, of from 0.1 to 5 weight percent,
preferably 1 to 3 weight percent,
d) colored pigments, of from 0.5 to 8 weight percent,
preferably 1 to 5 weight percent,
e) oxides and/or salts of rare metals, of 0.5 to 8 weight
percent, preferably 1 to 5 weight percent,
f) oxides and/or salts of rare earths, of 0.5 to 5 weight
percent, preferably 1 to 3 weight percent.
The fluorescent pigments should be insoluble in
water and organic solvents9 while the fluorescent materials,
though insoluble in water, should be soluble in organic
solvents. This allows these different substances to be
separated readily from each other and to be analytically
determined independently of one another. The colored pigments,
oxides and/or salts of rare metals and oxides and/or difficultly
solubLe salts or rare earths should be insoluble in water and
in organic solvents so that they rernain as a residue in all
instances and can be analytically identified side by side
without equivocation.
To distribute the various substance groups homo-
geneously in the tagging medium according to the invention,
they must be introduced into the melt of the polymers and
intensively mixed. For this purpose, mixing devices with
extremely good shearing and kneading effect have proven
effective. Single-screw extruders are less suitable for the
purpose. Twin-screw extruders are suitable if they develop
high shearing forces. What haveproved effective are, e.g.,
the twin-screw kneader, Model ZSK of the firm of Werner &
Pfleiderer of Stuttgart or the planetary rolling extruder,
Model EKK of the firm of Battenfelt in ~ochum. The batch
operating positive mixer of the Banbury type also appears to
be suitable. The homogeneous mixtures were then granulated
along a cooling conveyor and breaker. The fragmented
granulates should preferably exhibit diameters of less than
15 mm.
The granulates should exhibit edge lengths of pre-
ferably 2 to 6 mm. Granulates of this type can be pulverized
without difficultly to powders with a grain size of less than
50 em, preferably even smaller than 20 em. Only such finely
ground powders which can optionally be freed from coarser
grains by air classification, can, e.g. be sprayed with
powdered herbicides and insecticides in the form of suspensions
from pressure containers, without leading to dissociation or
even clogging the spraying systems. Since herbicides and
insecticides generally have a particle size range of 50 em,
-- 5
preferably even less than 20 em, the tagging material accord-
ing to the invention, must also be of the same fine particle
size. For the tagging of varnish systems also9 it is
necessary that extremely finely ground particles be used,
since varnish systems partially exhibit layer thicknesses of
20 em. Of course7 the constituents of the tagging means
must also be correspondingly fine grained; thus the iron
powder should exhibit a maximal grain size of lO em. The
other components as well should be correspondingly finely
pulverized and be worked into the mixture with fine dis-
tribution.
Exhaustive tests have shown that none of the common
thermoplastic materials suitable for the production of` tagging
means for explosives, are suitable for tagging means of finely
dispersed systems. The high molecular plastics such as poly-
ethylenes, polypropylenes, polyamides, po~ycarbonates, poly-
esters, polyoxymethylenes and acrylonitrile butadiene
styrene-copolymers cannot, either at normal temperatures or
under liquid nitrogen, be pulverized to tagging means of
such fine granulation as would be required.
Surprisingly, however, powder varnishes with an
uncured polyacrylate, polyester or polymer epoxide base are
suitable both for thermoplastic processing and Jo incorporate
at the same time all of the components of the tagging means
into a homogeneous mixture and to permit extremely fine pul-
verization of the rehardened mixture. The uncured polymer
components of powder varnishes with a polyacrylatel polyester
or polymer epoxide base, while they can be procured as such
from their manufacturers, are normally used only together with
a second or crosslinking component. Such crosslinking com-
ponents should not be present in the compositions of the pre-
:12~LZ~21
sent invention since they convert the thermoplastic polymers
on heating into duromers. Also, these relatively low mole- ¦
cularly crosslinking components can react with the finely
pulverized substances to be tagged to give undesired by-pro-
ducts. Thus, using uncured polymer components of powder
varnishes having a polyacry]ate, polyester or polymer epoxide
base for the production of tagging means for finely dispersed
systems constitutes a totally unusual and seemingly inappro-
priate use of these polymers.
Testing of the polymers, and the tagging means pro-
duced from them according to the invention, indicated, through
differential thermoanalysis, that these polymers all exhibit
a distinct vitreous transition point in the range of 50-80C.
In addition, these thermoplasts having melting points in the
range between 90 and 130C. They are, therefore, individually
and collectively with the other components, easily extruded,
and, after solidification at room temperature, easily and
simply pulverized to extremely fine powders.
The characteristic data of the polymer used under
the conditions of the differential thermoanalysis can be cited
as an additional criterion for the identification and decoding
of the tagging means.
The abundantly present ferromagnetic components
serve, as discussed above, for locating and separating the
proposed tagging means according to the invention from the
finely dispersed systems. Iron powders with a maximal
particle size of less than 10 em have been shown to be parti-
cularly effective as ferromagnetic materia]s. Iron powders
of this type are commercially available, e.g., from the firm
of E. MERCK, Darmstadt. In principle, however, all other
ferromagnetic alloys are suitable if available in
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sufficently fine powder form. If these allows should contain
relatively rare alloy components, they can also, in principle,
still be used for identification and decoding.
In principle, all pigments can be used as
fluorescent pigments which can be clearly distinguished from
each other by their fluorescence spectrum and their inherent
color. Examples oF suitable fluorescent pigments are those
of the firm of Industrial Colours Ltd., of England under the
designation FLARE* 910, orange, green and yellow commercial
pigments or the LUMILUX* C-luminescent pigments of the firm
of Riedel-de Haen AG. As fluorescent materials, all types can
be employed which can be dissolved from the tagging means with
the aid of organic solvents. The fluorescent materials should
preferably be insoluble in water so that they cannot be dis-
solved away in advance from the tagging means by water.
Examples of suitable fluorescent materials are the
products sold by the Ciba firm under the designations UVITEX*
OB, UVITEX* 127 and UVITEX* OB-P and by the ICI firm under
the designations FLUOLITE* XNR and FLUOLITE* XMP. As colored
pigments, all adequately insoluble and heat-stable pigments
can be employed, whose emission spectrum can be clearly
identified. Suitable colored pigments are, e.g. Sicoplast*
Yellow 12-0190 and Sicoplast* Red 32-0300, as well as the pig-
ments sold by the ICI firm under the designation Waxoline*,
with the colors blue, ruby-red, green and yellow.
As difficultly soluble and heat-stable oxides and/or
salts of rare metals, e.g., titanium oxide, copper oxide,
zinc oxide, strontium carbonate, cadmium sulfide, antimony
trioxide, barium sulfate, lanthanum trioxide and bismuth tri-
oxide can be used. As oxides and/or difficultly soluble salts* trade marks
-- 8
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of the rare earths, cerium (IV) oxide as well as the other
oxides or oxalates, of the lanthanides can be used.
Additionally, heat-stable oxides of low solubility and/or
salts of al7 metals were used sing7y or in combination, as
long as they could be identified unequivocally 'Dy micro-
analysis, e.g., by X-ray fluorescence spectroscopy.
In the following examples a number of typical
embodiments of the tagging means according to the invention
are described. All indications of percentage herein are
10 weight percentages.
Example 1
15.2 kg acrylate resin ~74.9%)
1.5 kg iron powder (10.0%)
1.2 kg fluorescent pigment ( 8.0%)
0.5 kg lanthanum (III) oxide ( 3.5%)
006 kg antimony trioxide ( 3.6%)
are introduced as dry powders in a fluid mixer of the ~enschel
type with a volume of 75 L and an rpm of the mixing device of
1600 and mixed for 1 minute. This mixture is poured into the
charging container of a twin-screw kneader of the type Werner
& Pfleiderer ZDK 57 M 50 and homogenized at a screw rpm of 250
and a mass temperature range of 110-130C. The homogenized
product is discharged and granulated along a conveyor cooling
installation with a crusher. The fragmented granulate is pul-
verized in a pulverization apparatus of the type Micropul ACM
60 at a carrier gas temperature of maximally 35C quantitatively
to a maximal particle size of 60 em. The product has a
particle size distribution of` from 30 to 60 em with a mean
weight value of 12 em and a percentile of 86% 20 em. After
subsequent air classification in a Walther-Industrie vortex-
type separator of the Model 250, 70% of product with a clean
L
upper particle limit of 20 em is separated.
The ingredients used in Example 1 were:
Acrylate re _ :
L.umitol LR 8655, an acrylate resin containing
hydroxyl groups, with a DSC temperature of 62 - 64~C and a
hydroxyl number of 78.2 mg KOG/g. Lumitol is a trademark
of the BASF firm, West Germany.
Iron powder:
3819 with a maximal grain size of 10 mm and a
purity of 99.5%. 3819 is a type designation of the MERCK
firm, West Germany.
Fluorescent pigment:
Flare 910 yellow 27, yellow inherent color. Flare
is a trade mark of the firm of Industrial Colours Ltd.,
England.
Cerium (IV) oxide:
A product of the firm of MERCK, West Germany,
with a purity of 99.9%.
TIMGNOX - WHITE STAR with a purity of 99%. TIMONOX
WHITE STAR is a trade mark of the firm of ASSOCIATED LEAD
Manufacturers Ltd., England.
Example 2
The following dry, powdered components were intro-
duced into a plough bar mixer of the model Leodige FM 130 D
with a volume of 130 L and an rpm of the mixer of 1,000,
mixed for 3 minutes and then poured into the charging con-
tainer of a planetary roller extruder of the type Battenfeld -
EKK PDE 100 EV, subsequently homogenized at a screw rpm of 30
and a mass temperature of 90 - 120C and extruded and granu-
-- 10 --
lated along a cooling belt with a crusher.
22.4 kg acrylate resin (74.9%)
3.0 kg iron powder ~10.0%)
2.4 kg fluorescent pigment ( 8.0%~
1.0 kg lanthanum (III) oxide ( 3.5%)
1.2 kg antimony trioxide ( 3.5%)
The fragmented granulate obtained in this way waspulverized in accordance with Example 1 to an end fineness of
50 em, a means weight value of 8.5 em and a percentage of 88%
below 15 em. By air classification with a Donaldson air
classifier of the model Accucut C-24, 70% of a powder with
clean upper grain limit of 15 em was separated out.
The materials used in Example 2 were:
Epoxy resin:
Epikote 1004, an epoxy resin with a DSC peak
temperature of 62 and an epoxy equivalent weight of 805 -
940 g. Epikote is a trade mark of the firm of SHELL, Chemistry,
England.
Iron powder, fluorescent pigment lanthanum ~III) oxide,
antimony trioxide:
-
Materials as in Example 1.
Example 3
Using essentially the process of Example 2 (maximumextruder temperature of 135C), a fragment granulate is pro-
duced from the following dry, powdered components and pul-
verized to an upper grain limit of 80 em. The product has a
mean weight value of 18 em and a percentage of 84% 30 em. 77%
of a powder with a clean upper grain limit of 30 em is
separated out:
-- 11 --
2~
15.0 polyester resin (74.9%)
2.0 kg iron powder (10.0%~
1.6 kg fluorescent pigment ( 8.0%~
0.7 kg lanthanum (III~ oxide ( 3.5%~
0.7 kg antimony trioxide ( 3.6%~
The materials used in Example 3 were:
Polyester resin:
Crylcoat 280, a polyester resin containing hydroxyl
groups and having a flow rate/ASTM D 1238, A of 10 g/min, and
a hydroxyl number of 50 mg KOH/g. Crylcoat is a brand name
of the UCB, Specialties Chemical Division, Belgium.
Iron powder, fluorescent pigment, lanthanum (III~ oxide,
antimony trioxide:
_
Materials as in Example 1.
The yield in Examples 1, 2 and 3 can be increased
by mixing the coarse grains precipitated during air classifi-
cation with the next batch of granulate so that it undergoes
pulverization once again.
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