NO840161L - MARKING MEASURES, PROCEDURES FOR THE PREPARATION OF SUCH AS, AND USE OF THEM - Google Patents

Abstract

1. A tracer (marking agent) containing a) at least 1 per cent by weight of iron powder and:or powder of a ferromagnetic alloy and at least tow of the following groups of substances : b) fluorrescent pigments ; c) organic solvent-soluble, water-insoluble fluorescent materials ; d) colorant pigments ; e) sparingly soluble and heat-stable oxides and/or salts of rare metals ; f) oxides and/or sparingly soluble salts of rare-earth metals ; in microanalytically well detectable amounts in the form of a homogeneous mixture with a thermoplastic material, characterized in that the thermoplastically processable material is the uncured polymer component of powder varnishes based on polyacrylates, polyesters, or polymeric epoxides.

Description

The object of the present invention is marking agents, especially for marking finely dispersed systems, which allow the identification of the substances used with regard to origin and composition and possibly also date of manufacture with the aid of microanalytical methods. Furthermore, the invention relates to the method for producing such marking agents and their use, in particular for marking finely powdered substances.

The increasing extent of theft and illegal use

of explosives has led to the need to be able to unambiguously demonstrate the origin, nature and possibly also the time of manufacture of explosives. A number of marking agents have therefore already been proposed or brought to the market. Marking agents for explosives are, for example, described in US Patent Nos. 4,053,433, 3,772,200, 3,897,284, 4,131,064, 4,197,104, 3,961,106, 3,967,990 and 3,993,838.

Furthermore, we have developed improved marking agents, which in high-molecular, thermoplastically processable polymers contain incorporated ferro-magnetic parts as well as possibly fluorescent pigments, soluble and insoluble fluorescent substances, color pigments, oxides and/or salts of rare metals as well as oxides and/or poorly soluble salts of rare earth species in microanalytically detectable quantities. They are produced by homogenous fusion of the components, granulation and grinding.

These marking agents are the subject of a BRD patent application

P 32 03 373.7.

It was now established that there is a strong widespread need

for marking agents, not only for explosives, but for a number of additional substances. Fine-disperse systems, especially finely powdered substances with high efficiency or high value and particularly high quality requirements, must be marked so that it can also be determined later whether they are original goods. In some cases, it is even desired, such as in the case of explosives, that not only the manufacturer, but also the date of manufacture and date of filling, can be determined later. Fine powdery substances of this type are, for example, herbicides, pesticides and fertilisers, but also finely dispersed systems such as high-quality special varnishes etc.

Markers for explosives are unsuitable for such purposes, since they are too coarse-grained, and with the help of special technology, such as painting under liquid nitrogen or the free-fall process, they cannot be sufficiently finely divided. The plastics proposed by the applicant as marking agents for explosives, such as polyethylene, polypropylene, polyamide, polycarbonate, polyester, polyoxymethylene or acrylonitrile/butadiene/styrene copolymers, also cannot be painted at extremely low temperatures, such as under liquid nitrogen, to the desired grain size of less than 50 um, preferably less than 20 um.

The invention has set itself the task of providing marking agents for finely dispersed systems, which on the one hand can be easily and economically produced, and on the other hand can be ground into homogeneous particles which are less than 50 um, preferably less than 20 um. The marking agents must also be resistant to water and moisture, but must be easily distinguishable from the fine powdery substances and easily identifiable microanalytically.

It has now been found that the uncured polymer components from powder coatings based on polyacrylates, polyesters or polymeric epoxies are excellently suited to be used as thermoplastically processable material to incorporate iron powder and/or powder of ferromagnetic alloys, as well as the further microanalytically well detectable substances , in the smelting, and then without further ado can be ground to particle sizes of less than 50 ym, preferably even less than 20 ym. The object of the present invention is thus marking agents that contain a) at least 1% by weight of iron powder and/or powder of ferromagnetic alloys, as well as at least two of the following substance groups,

b) fluorescent pigments,

c) water-insoluble fluorescent substances which are soluble in organic solvents,

d) color pigments,

e) sparingly soluble and heat-stable oxides and/or salts of rare metals, and f) oxides and/or sparingly soluble salts of rare earth species, homogeneously mixed in microanalytically detectable quantities in a

thermoplastic material, characterized in that it is thermoplastic

workable material are the uncured polymer components from powder coatings based on polyacrylates, polyesters or polymer epoxides.

The method according to the invention for the production of the marking agents is characterized by using the uncured polymer components from powder coatings based on polyacrylates, polyesters or polymeric epoxides as thermoplastically processable material, introducing the substances a)

to f) in the smelting, mix homogeneously, granulate the mixture, grind finely and possibly separate coarse grains by wind sifting.

The iron powder and/or the powder of the ferromagnetic alloy must be present in quantities of at least 1%, so that the marking agent can be extracted from the finely powdered substances with the help of magnets. Amounts of 3 - 20% by weight of ferromagnetic material are usually used. Amounts of 5 -

12% by weight has proven particularly suitable.

For unambiguous coding and decoding of the markers

according to the invention, there must be at least two of the substance groups fluorescent pigments, fluorescent substances, color pigments, oxides and/or salts of rare metals as well as oxides and/or sparingly soluble salts of rare earths. The more different substance groups are used, the greater the variability and the easier it is to obtain

an unambiguous coordination by manufacturer, date of manufacture and composition for the marked substance mixtures. In order to be able to detect the substance groups in the marking agents according to the invention also microanalytically, these must be present in the following amounts:

b) fluorescent pigments in amounts of 0.1 to 8% by weight, preferably 2 to 5% by weight, c) fluorescent substances in amounts of 0.1 to 5% by weight, preferably 1 to 3% by weight,

d) color pigments in amounts of 0.5 to 8% by weight, preferably

1 to 5% by weight,

e) oxides and/or salts of rare metals in amounts from 0.5 to 8% by weight, preferably 1 to 5% by weight, and f) oxides and/or salts of rare earths in amounts from 0.5 to 5% by weight, preferably 1 to 3% by weight.

The fluorescent pigments must be insoluble in water and organic solvents, while the fluorescent substances are indeed water insoluble, but must be soluble in organic solvents. In this way, these substance groups can be easily separated from each other and determined analytically independently of each other. Also, color pigments, oxides and/or salts of rare metals and, oxides and/or sparingly soluble salts of rare earths must be insoluble in water and organic solvents, so that in all cases they remain in the residue and then the meaning can be determined analytically next to each other.

To distribute the different substance groups homogeneously

1 the marking agents according to the invention, then they must be introduced into the melt of the polymer and mixed intensively. For this, mixing devices with extremely good shearing and kneading action have proven suitable. Single-screw extruders are not suitable for this. Twin-screw extruders are well suited when they develop high shear forces. For example, the twin-screw kneader of type ZSK from the company Werner&Pfléiderer, Stuttgart, or the planar roll extruder of type EKK from the company Battenfeld, Bochum, have proven suitable. Batch-working forced mixers of the Banbury type have also proven to be suitable. The homogeneous mixture is then passed over a cooling belt and granulated with a crusher. The splinter-like granules should preferably have a diameter of less than 15 mm.

The granules should preferably have edge lengths from 2 to

6 mm. Such granules can easily be ground into powder with a grain size of less than 50 µm, preferably also less than 20 µm. Only such finely ground powders, which may have been freed from larger grains by wind sifting, can be sprayed, for example, together with powdered herbicides and insecticides in the form of slurries from pressure containers, without this leading to splitting of the mixtures or clogging of the spray system. Since herbicides and insecticides mostly exist with particle sizes below 50 ym, in some cases even below 20 ym, the marking agents according to the invention must also be thus finely divided. Also for marking paint systems, it is necessary to use extremely finely ground particles, especially for paint systems that sometimes only have layer thicknesses of 20 ym. Of course, the substances contained in the marking agents must also be correspondingly finely divided. Thus, the iron powder used must have an upper grain limit of 10 ym. The other components must also be present in a similarly finely ground state, and incorporated finely distributed in the mixture.

In-depth investigations of the applicant have shown that all

ordinary thermoplastic materials, which, for example, are suitable for the production of marking agents for explosives, are unsuitable for marking agents for finely dispersed systems. The plastics, such as polyethylene, polypropylene, polyamide, polycarbonate, polyester, polyoxymethylene and acrylonitrile/butadiene/styrene copolymers, cannot be ground into finely powdered marking agents either at normal temperature or under liquid nitrogen, which is necessary in itself.

However, it has surprisingly turned out that the uncured polymer components from powder coatings based on polyacrylates, polyesters or polymer epoxides are suitable to be thermoplastically processed on the one hand and thus to absorb all the other components of the marking agent in a homogeneous mixture,

and on the other hand allow an extreme fine grinding of it on

newly solidified mixture. The uncured polymer components from powder coatings based on polyacrylates, polyesters or polymer epoxides can probably be obtained from the manufacturer individually, but they are, however, usually only used together with the other cross-linking components. According to the invention, these other cross-linking components must not be present, as they will convert the thermoplastic polymers into thermosetting plastics when the mixture is heated more strongly. There is also a risk that these relatively low molecular weight cross-linking components may also react with the finely powdered substances to be marked. The use of the uncured polymer components from powder coatings

on the basis of polyacrylates, polyesters or polymeric epoxides for the production of marking agents for finely dispersed systems thus constitute a completely unusual and actually inappropriate application of these polymers.

An examination of the polymers used in accordance with the invention and the marking agents produced therefrom by means of differential thermo-analysis has shown that all these polymers exhibit a distinct glass transition temperature in the range of 50 - 80°C. Furthermore, these thermoplastics have a melting point in the range between 90 and 130°C. They are therefore, on their own, and together with the other components, easily extrudable and, after solidification at room temperature, can be simply and easily ground into a very

fine powder.

The special data for the polymers used under the conditions of the differential thermo-analysis can be used as further criteria for identification and decoding of the marking agents.

As said, the ferromagnetic parts serve to detect and separate the marking agents according to the invention from the finely dispersed systems which are present in considerable excess to be marked. As ferromagnetic materials, especially iron powder with an upper grain size of less than 10 µm has proven to be particularly suitable. Such an iron powder is, for example, brought to the market by the company E. MERCK, Darmstadt. In principle, however, all other ferromagnetic alloys are also suitable, if they are available in sufficiently fine powder form. If these alloys contain relatively rare alloy constituents, these can in principle also be used for identification and decoding.

Fluorescent pigments are, in principle, all such pigments that can be clearly distinguished from each other by their fluorescence spectrum and their own colour. Examples of suitable fluorescent pigments are the pigments sold by the company Industrial Colors Ltd., England under the designation FLARE 910, orange, green and yellow, or the LUMILUX C light pigments from the company Riedel-de Haén AG. In principle, fluorescent substances are all types that are soluble in organic solvents, which can be released from the marking agents with the help of organic solvents. The fluorescent substances should preferably be water-insoluble, so that they cannot be released from the marking agents only with water.

Examples of suitable fluorescent substances are the products sold under the names UVITEX OB, UVITEX 12 7 and UVITEX OB-P by the company Ciba and under the names FLUOLITE XNR and FLUOLITE XMP by the company ICI. All sufficiently insoluble and heat-stable pigments whose emission spectrum is unambiguously identifiable can also be used as color pigments. Suitable dye pigments are, for example, Sicoplast Gelb 12-0190 and Sicoplast Rot 32-0300 as well as the pigments sold by the company ICI under the name Waxoline in the colors blue, ruby-red, green and yellow.

Examples of poorly soluble and heat-stable oxides and/or salts of rare metals are titanium dioxide, copper oxide, zinc oxide, strontium carbonate, cadmium sulphide, antimony trioxide, barium sulphate, lanthanum trioxide and bismuth trioxide. As oxides and/or poorly soluble salts of the rare earth species, Cer-IV oxide as well as the other oxides, respectively oxalates, of the lanthanides come into question. In addition, poorly soluble and heat-stable oxides and/or salts of all metals can be used alone or in combination, if they can be clearly identified microanalytically, for example by X-ray fluorescence spectrometry.

In the following examples, some typical embodiments of the marking agents according to the invention are described, as well as their production. All percentages here are percentages by weight.

Example 1

is introduced as dry powder into a fluid mixer of the Henschel type with a volume of 75 liters and with a speed of

on the mixing device at 1600 revolutions per minute, and it is thoroughly mixed for 1 minute. This mixture is filled into a feed container for a two-screw kneader of the type Werner & Pfleiderer ZSK 57 M 50, and is homogenized with a screw speed of 2 50 revolutions per minute. minute and a mass temperature range of 110-130°C. The homogenized product is passed over a belt cooling system with crushers, and is granulated. The shell-shaped granules are ground in a grinding device of the type Micropul ACM 60 at a carrier gas temperature of max. 35°C quantitatively to an upper grain size of 60 ym. The product has a grain size distribution of 3 - 60 ym with a weight average value of 12 ym and a proportion of 86% <20 ym. During subsequent wind sieving in a Walther-Industrie vortex sieve of the type 250, 70% of a product with a pure upper grain limit of 20 ym could be separated.

Acrylate resin:

"Lumitol" LR 8 6 55, a hydroxyl group-containing acrylate resin with a DSC peak temperature of 62 - 64°C and a hydroxyl number of 78.2 mg KOH/g. "Lumitol" is a trademark belonging to the company

BASF, FRG.

Iron powder:

3819 with an upper grain size of 10 ym and a purity of 99.5%.

3819 is a type designation for the company MERCK, BRD.

Fluorescent pigment:

"Flare" 910 yellow 27, yellow self-colour. "Flare" is a trademark belonging to the company Industrial Colors Ltd., England.

Cerium IV oxide:

A product from the company MERCK, BRD, with a purity of

99.9%.

Antimony trioxide:

"TIMONOX WHITE STAR" with a purity of 99%. "TIMONOX WHITE STAR" is a trademark belonging to the company ASSOCIATED LEAD Manufactures Ltd., England.

Example 2

The following dry, powdery components are added to a Lodige FM 130 D ploughshare mixer with a volume of 130 liters and a revolution rate for the mixing device of 1000 revolutions per minute. minute. It is thoroughly mixed for 3 minutes and then the mixture is introduced into the introduction container in a planetary roller extruder of the type Battenfeld - EKK PDE 100 EV, and then homogenized at a screw speed of 30 revolutions per minute. minute and a mass temperature of 90 - 120°C and recorded on a cooling belt with crushers and granulated.

The shell-shaped granules thus obtained are ground in accordance with example 1 to a final fineness of 50 ym at a weight average value of 8.5 ym and a proportion of 88% below 15 ym. When sifting using a Donaldson wind sifter of the type Accucut C-24, 78% of a powder with a clean upper grain limit of 15 ym can be separated from this.

Epoxy resin;

"Epikote" 1004, an epoxy resin with a DSC peak temperature of 62°C and an epoxy equivalent weight of 850 - 940 g. "Epikote" is a trademark of SHELL Chemie, England.

Iron powder, fluorescent pigment, lanthanum TII oxide, antimony trioxide:

Products as in example 1.

Example 3

In accordance with the method in example 2 (mass temperature in the extruder is deviantly max. 135°C), a shell-shaped granulate is produced from the following dry, powdery components which is ground to an upper grain limit of 80 ym. The product has a weight average value of 18 ym and a proportion of 84% <30 ym. In accordance with example 2, 77% of a powder with a clean upper grain limit of 30 ym can be separated from it:

Polyester resin:

"Crylcoat" 280, a hydroxyl-containing polyester resin with a flow rate/ASTM D 1238.A of 10 g/10 min. and a hydroxyl number of 50 mg KOH/g. "Crylcoat" is the trade name for a product from UCB, Specialties Chemical Division, Belgium.

Iron powder, fluorescent pigment, lanthanum III oxide, antimony trioxide:

Products as in example 1.

The yields in examples 1, 2 and 3 could be increased by mixing the coarse grains precipitated by wind sifting into the next batch of granules, so that they could again be subjected to painting.

Claims (8)

1. Markers containing a) at least 1% by weight of iron powder and/or powder of ferro-magnetic alloys, as well as at least two of the following substance groups: b) fluorescent pigments, c) water-insoluble fluorescent substances which are soluble in organic solvents, d) color pigments, e) poorly soluble and heat-stable oxides and/or salts of rare metals, and f) oxides and/or poorly soluble salts of rare earths species, homogeneously mixed in microanalytically detectable amounts in a thermoplastic material, characterized in that the thermoplastically processable material is the uncured polymer component from powder coatings based on polyacrylates, polyesters or polymeric epoxides. 2. Markers according to claim 1, characterized in that the melt of the mixture after cooling is granulated and finely ground. 3. Marking agents according to claim 1 or 2, characterized in that the particle size after painting is less than 50 ym, preferably less than 20 ym. 4. Marking agents according to claims 1 to 3, characterized in that a) the iron powder and/or the powder of the ferromagnetic alloy is present in amounts from 3 to 20% by weight, and that at least two of the following substances are present in the following amounts: b) fluorescent pigments in amounts from 0.1 to 8% by weight, c) fluorescent substances in amounts from 0.1 to 5% by weight, d) color pigments in amounts from 0.5 to 8% by weight, e) oxides and/or salts of rare metals in amounts from 0.5 to 8% by weight, and f) oxides and/or salts of rare earth species in amounts from 0.5 to 5% by weight. 5. Process for the production of marking agents containing a) at least 1% by weight of iron powder and/or powder of ferro-magnetic alloys as well as at least two of the following substance groups: b) fluorescent pigments, c) water-insoluble fluorescent substances which are soluble in organic solvents, d) color pigments, e) poorly soluble and heat-stable oxides and/or salts of rare metals, and f) oxides and/or poorly soluble salts of rare earths species, homogeneously distributed in microanalytically detectable amounts in a thermoplastic material, characterized by using the uncured polymer component from powder coatings based on polyacrylates, polyesters or polymeric epoxides as a thermoplastic material, introducing the substances a) to f) into the melt, mixing homogeneously, granulating the mixture, grinds finely and possibly separates coarse grains by wind screening. 6. Method according to claim 5, characterized in that the iron powder or the powder of the ferro-magnetic alloy is used in amounts from 3 to 20% by weight, and that at least two of the following substance groups are used in the following amounts: b) fluorescent pigments in amounts from 0.1 to 8% by weight, c) fluorescent substances in amounts from 0.1 to 5% by weight, d) color pigments in amounts from 0.5 to 8% by weight, e) oxides and/or salts of rare metals in amounts from 0.5 to 8% by weight and f) oxides and/or salts of rare earth species in amounts from 0.5 to 5% by weight. 7. Method according to one of claims 5 or 6, characterized in that the particle size after painting is less than 50 µm, preferably less than 20 µm. 8. Use of the marking agents according to one of claims 1 to 4 for marking finely dispersed systems.