EP4594274A1

EP4594274A1 - Stable hydrogen peroxide gels and emulsions suitable for rock fragmentation

Info

Publication number: EP4594274A1
Application number: EP23777308.0A
Authority: EP
Inventors: Karol Lorent; François Dabeux
Original assignee: Solvay SA
Current assignee: Solvay SA
Priority date: 2022-09-28
Filing date: 2023-09-28
Publication date: 2025-08-06
Also published as: WO2024068812A1

Abstract

The invention relates to the use of a hydrogen peroxide (H₂O₂) solution stabilized with dipicolinic acid and a phosphonic acid compound in combination with a copolymer of propylene glycol and ethylene glycol for the preparation of stable gels or emulsions. Furthermore, the invention relates to a gel or emulsion containing hydrogen peroxide, dipicolinic acid, phosphoric acid compound and a copolymer of propylene glycol and ethylene glycol, and to the use of the gel or emulsion in rock fragmentation

Description

Stable hydrogen peroxide gels and emulsions suitable for rock fragmentation

This application claims priority of the application filed on 28 September 2022 in EUROPE with Nr 22198234.1, the whole content of this application being incorporated herein by reference for all purposes.

TECHNICAL FIELD

The invention relates to the use of a hydrogen peroxide solution stabilized with dipicolinic acid and a phosphonic acid compound in combination with a copolymer of propylene glycol and ethylene glycol for the preparation of stable gels or emulsions. Furthermore, the invention relates to a gel or emulsion containing hydrogen peroxide, dipicolinic acid, phosphoric acid compound and a copolymer of propylene glycol and ethylene glycol, and to the use of the gel or emulsion in rock fragmentation.

TECHNICAL BACKGROUND

Most of the commercial and mining explosives used in the world today are based on ammonium nitrate, which is a strong oxidizer. However, these compositions have several disadvantages, inter alia the generation of toxic NO_X fumes during detonation. In order to overcome these disadvantages, hydrogen peroxide (H2O2), which is also a strong oxidizer, is used more and more often in explosive (blasting) compositions. Explosive compositions that contain hydrogen peroxide are for example described in US 3,047,441 or US 4,942,800.

However, hydrogen peroxide is a self-reactive, self-heating substance, i.e. its decomposition accelerates as the temperature rises and usually exponentially. A self-heating process producing heat faster than it can cool is called as runaway reaction. In case of hydrogen peroxide, the runaway reaction is accompanied by the generation of large volumes of gas and thus hydrogen peroxide is a strong explosive compound. This makes its handling difficult, in particular with respect to storage and transportation. Compounds, which stabilize hydrogen peroxide for a better handling, are known in the art and for example described in WO 2006/016990. Nevertheless, there is still the need to provide hydrogen peroxide solutions having an improved stability.

Furthermore, in order to use hydrogen peroxide solutions in or as explosive (blasting) composition for example in rock fragmentation, it is necessary that the desired decomposition property of the composition can be controlled. Therefore, in most of the cases, gel-forming agents are added to the hydrogen peroxide solution to obtain a gel or emulsion, which provides a better handling and controlling of the explosive composition. Usually, gelling agents used in such compositions are polymers, in particular polymers that are produced by solution polymerizations as for example described in US 4,942,800.

However, a problem in this regard is the compatibility between polymer used as gelling agent and hydrogen peroxide, because hydrogen peroxide has the tendency to decompose when it comes in contact with a polymer. This results into instability of the gel/emulsion, which is difficult to control.

Therefore, object of the invention was to provide a gel or emulsion containing hydrogen peroxide, which shows a sufficient and controllable stability and thus is suitable for using it for example in rock fragmentation.

SUMMARY OF THE INVENTION

The present invention relates to the use of a hydrogen peroxide solution containing dipicolinic acid (DPA) and a phosphonic acid compound in combination with a copolymer of propylene glycol and ethylene glycol for the preparation of gels or emulsions.

Furthermore, the invention relates to a gel or emulsion containing the hydrogen peroxide, dipicolinic acid (DPA), a phosphonic acid compound and a copolymer of propylene glycol and ethylene glycol.

The gel or emulsion according to the invention shows a sufficient stability and is suitable for rock fragmentation.

DETAILED DESCRIPTION OF THE INVENTION

Before the present formulations of the invention and used thereof are described, it is to be understood that this invention is not limited to particular formulations described, since such formulations may, of course, vary. It is also to be understood that the terminology used herein is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

As used herein, the singular forms "a", "an", and "the" include both singular and plural referents unless the context clearly dictates otherwise. By way of example, "an additive" means one additive or more than one additives.

The terms "containing", "contains" and "contained of' as used herein are synonymous with "including", "includes" or " comprising", "comprises", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms “containing”, “contains”, "comprising", "comprises" and "comprised of' as used herein comprise the terms "consisting of, "consists" and "consists of.

Throughout this application, the term "about" is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value.

As used herein, the term “average” refers to number average unless indicated otherwise.

As used herein, the terms “% by weight”, “wt.- %”, “weight percentage”, or “percentage by weight” are used interchangeably.

The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

All references cited in the present specification are hereby incorporated by reference in their entirety. In particular, the teachings of all references herein specifically referred to are incorporated by reference. Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

In the following passages, different alternatives, embodiments and variants of the invention are defined in more detail. Each alternative and embodiment so defined may be combined with any other alternative and embodiment, and this for each variant unless clearly indicated to the contrary or clearly incompatible when the value range of a same parameter is disjoined. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Furthermore, the particular features, structures or characteristics described in present description may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art.

In order to provide a gel or emulsion suitable for example for rock fragmentation, according to the invention, a hydrogen peroxide (H2O2) solution, which contains dipicolinic acid and a phosphonic acid compound, is used in combination with a copolymer of propylene glycol and ethylene glycol. According to the invention, dipicolinic acid and the phosphonic acid compound are used as stabilizer compounds in the hydrogen peroxide solution to stabilize the hydrogen peroxide solution. Due to the use of such a stabilized hydrogen peroxide solution in combination with a copolymer of propylene glycol and ethylene glycol it is possible to provide a stable gel or emulsion suitable for rock fragmentation.

As mentioned above, it is state of the art to use stabilizer compounds for stabilizing hydrogen peroxide solutions, in particular for stabilizing concentrated hydrogen peroxide solutions, in order to ensure that the solutions can be storage and transported safely. Different types of stabilizer thereof are known in the art, for example radical scavengers, inorganic stabilizer, chelating agents etc.. Typical examples are ascorbic acid, hydroxyphenyl acetic acid, hydroxybenzoic acid, 2-picolinic acid, 8-hydroxyquinoline, phenacetin, dipicolinic acid, gallic acid, tannic acid, stannate, sodium pyrophosphate, or phosphonic acid stabilizers.

The inventors of the application found that the use of dipicolinic acid (DPA), which is a radical scavenger, in combination with a phosphonic acid compound, which is a chelating agent, provides the best stabilizing effect on hydrogen peroxide solution, i.e. this combination considerably reduces the degradation of hydrogen peroxide solution compared to the hydrogen peroxide solution, which does not include the stabilizer compounds, i.e. is un-stabilized. Considerable reduction according to the invention means, if the hydrogen peroxide solution is heated at a temperature of 75 °C over 6 hours, the decomposition of hydrogen peroxide can be reduced by a factor of 5, preferably by a factor of 8, more preferably by a factor of 10 compared to a hydrogen peroxide solution that does not contain any stabilizer compound.

In other words, due to the use of DPA in combination with a phosphonic acid compound the un-desired decomposition of hydrogen peroxide at ambient conditions can be avoided and thus the stability of the hydrogen peroxide solution of the invention is sufficient for safe transportation and storage. Preferably, the hydrogen solution of the invention consists of hydrogen peroxide, dipicolinic acid and a phosphonic acid compound as defined above.

According to the invention, it is preferred that the phosphonic acid compound is a compound having the formula

N CR^PChHiK wherein integer x is at least 3, preferably 3 to 6, more preferably 4 or 5, and R¹ and R² are each independently hydrogen or an alkyl group of 1 to 4 carbon atoms.

In particular it is preferred that the phosphonic acid compound is selected from the group consisting of amino tri(methylene phosphonic) acid, diethylenetriamine penta (methylene phosphonic) acid, hexamethylene diamine tetra(methylene phosphonic) acid, bis hexamethylene triamine penta (methylene phosphonic) acid, salts thereof and a combination thereof. More preferably, the phosphonic acid compound is diethylenetriamine penta (methylene phosphonic) acid (DTPMP).

In order to use the hydrogen peroxide solution as or in an explosive composition it is preferred that the hydrogen peroxide solution of the invention is a concentrated hydrogen peroxide solution, preferably a concentrated aqueous hydrogen peroxide solution. More preferably, the hydrogen peroxide solution has a hydrogen peroxide concentration between 40 and 80 wt.-%, between 50 and 70 wt.-%, most preferably between 55 and 65 wt.-%, based on the total weight of the hydrogen peroxide solution.

The hydrogen peroxide solution can be obtained by every production method known in the art and is commercially available. Typical commercially available hydrogen peroxide solutions are aqueous hydrogen peroxide solutions, which have a hydrogen peroxide concentration of 60 wt.-%. The purity degree of these solutions in terms of organic content may be different and is between 99% up to 100 %. Examples for such hydrogen peroxide solutions are ST60 Voikaa (purity degree in terms of organic content is of 99.5 %), ST60 Jemeppe (purity degree in terms of organic content is of 99.5%) and RO60 Line Herten (purity degree in terms of organic content is of approx. 100 %) obtainable from Solvay.

The hydrogen peroxide solution of the invention is obtained by adding dipicolinic acid and a phosphonic acid compound, preferably as aqueous solutions, to the (aqueous) hydrogen peroxide solution and subsequently mixing. The obtained hydrogen peroxide solution contains dipicolinic acid and the phosphonic acid compound in a sufficient amount, i.e. in an amount, which ensures that the obtained hydrogen peroxide solution shows the desired stability.

It is preferred that the hydrogen peroxide solution contains between 50 and 500 ppm, between 100 and 400 ppm, most preferably between 150 and 300 ppm of dipicolinic acid. Dipicolinic acid amounts of higher than 500 ppm do not show any further beneficial effect.

The concentration of the phosphonic acid compound present in the hydrogen peroxide solution is preferably between 10 and 400 ppm, between 30 and 300 ppm, and more preferably between 50 and 200 ppm. The concentration of the phosphonic acid in the solution should not exceed 500 ppm.

In particular, it is preferred that the hydrogen peroxide solution dipicolinic acid in an amount of 100 to 300 ppm, preferably of 100 to 200 ppm, in combination with a phosphonic acid compound in an amount of 50 to 250 ppm, preferably of 100 to 200 ppm in order to obtain a stabilized hydrogen peroxide solution.

In order to ensure that the hydrogen peroxide solution is suitable for explosive (blasting) composition, the hydrogen peroxide solution of the invention is used in form of a gel or emulsion. The inventors of the invention found that in order to avoid undesired decomposition of the hydrogen peroxide when it comes in contact with the gelling agent (polymer), it is beneficial that the gel or emulsion contains a copolymer of propylene glycol and ethylene glycol. Such a gel or emulsion shows a sufficient stability and thus is suitable for explosive composition, in particular is suitable for rock fragmentation.

The copolymer of propylene glycol and ethylene glycol is preferably present in the gel or emulsion of the invention in an amount of 1 to 20 wt.-%, more preferably of 2 to 15 wt.-%, most preferably of 5 to 10 wt.-%, based on the total amount of gel or emulsion.

According to the invention, it is preferred that the copolymer of propylene glycol and ethylene glycol is a copolymer having the formula HO(C2H4O)b(C3H₆O)a(C2H₄O)bH, wherein a is an integer such that the hydrophobe base represented by (CsHeO) has an average molecular weight of from 2700 to 4500 and b is an integer such that the hydrophile portion is represented by (C2H4O) constitutes from 40 to 85 wt.-% on the total weight of the copolymer. Preferably, the hydrophobe base has an average molecular weight from 2750 to 4000, more preferably of 4000, and the hydrophile portion constitutes preferably from 45 to 80 wt.-% of the copolymer, more preferably of 70 wt.-% based on the total weight of the copolymer.

In particular, the use of the hydrogen peroxide solution of the invention in combination with the copolymer of propylene glycol and ethylene glycol results into the formation of hydrogels, in particular into the formation of stable hydrogels. In combination with further polymers a further gelation can be obtained These polymers act usually as gelling agents in aqueous solutions.

Preferably, these polymers are obtained by solution polymerisation, more preferably by aqueous solution polymerization with the hydrogen peroxide solution. Therefore, water-soluble polymer resins are preferred. Typical examples, which may be used as gelling agent are polyvinyl alcohol, polyacrylamides, cationic resins including polymeric amines and quaternary ammonium polymers such as polyethyleneimines, polyalkylene-polyamines, poly(vinylbenzyltrimethylammonium) chlorides, poly(diallyldimethylammonium) chlorides, poly(glycidyltrimethylammonium) chlorides and poly(2-hydroxpropyl-l-N-dimethylammonium) chlorides, polyacrylic, polymethacrylic and poly-a-hydroxyacrylic acids and their alkali metal or ammonium salts, esters of polyacrylic, polymethacrylic and poly-a- hydroxyacrylic acids such as 2-hydroxyethyl methacrylate, polyethylene oxide)s known by the name of polyethers, poly(N-vinyl-2-pyrolidone), polyvinyl ether homopolymers of alkyl vinyl ethers, copolymers of maleic anhydride with styrene or with ethylene and the surface-active polymers known by the name of “polysoaps” such as poly(2-vinylpyridine) and poly(4-vinylpyroddine) and their alkylated derivatives, polyionenes, epoxy resins, modified polyethylene glycol, acryloyldimethyltaurate copolymer, or combinations thereof. Generally, cationic (SO3'Na⁺) copolymers of acrylamide / acrylate are preferred. In particular, it is preferred that the polymer is an acryloyldimethyltaurate copolymer, for example a copolymer of acrylamide / sodium acryloyldimethyltaurate or a copolymer of hydroxyethyl acrylate and sodium acryloyldimethyltaurate.

The gel or emulsion of the invention may have a viscosity of greater than 10 Pa*s prior to the entrainment of gas bubbles and measured by using a Brookfield RVT viscometer, #7 spindle of 50 r.p.m., preferably the viscosity is in a range of 5 to 50 Pa*s, more preferably of 10 to 35 Pa*s, most preferably of 10 to 25 Pa*s. The gels or emulsion of the invention can be pumped.

The pH of the obtained gel or emulsion of the invention is not narrowly critical. However, it is preferred that the pH value is between 0 to 8, more preferably between 0.4 and 6 or between 1 and 4, and may be controlled by suitable addition of conventional additives, for examples inorganic or organic acid and salts like H3PO4 or NasPC . A lower pH value may result into a better stability of the gel or emulsion.

In particular, the gels or emulsions of the invention containing the compounds as defined above show a sufficient stability and thus can be used in rock fragmentation. Therefore, the gel or emulsion of the invention may be combined with fillers and/or further combustible materials usually used in explosive compositions, for example nitrate salts, perchlorate salts, sodium/potassium peroxide or nitric acid as well as ethylene glycol, propylene glycol, benzene or gasoline.

The present invention is further illustrated by the following examples. It should be understood that the following examples are for illustration purposes only, and are not used to limit the present invention thereto.

EXAMPLES

In order to determine which hydrogen peroxide solution and which gel/ emulsion thereof shows the required stability the thermal stabilities of different hydrogen peroxide solutions and gels/emulsions were measured.

In Figure 1 the thermal stabilities of hydrogen peroxide solutions as determined in Example 1 are shown.

Figure 2 shows the thermal stabilities of gels/emulsions as determined in Example 2.

Figure 3 and Figure 4 refers to results obtained by using the thermals stability standard measurement test EN- 13621-2 as described in Example 3. List of abbreviations and synonyms

DPA: Dipicolinic acid

DTPMP: Diethylenetriamine penta (methylene phosphonic) acid

SAPP: sodium pyrophosphate

Tylose®: Methyl 2-hydroxyethyl cellulose

Pluronic® F127: copolymer of polyethylene glycol and propylene glycol available from BSAF

Sepineo® P600: Acrylamide / sodium acryloyldimethyltaurate copolymer Sepineo® DERM: hydroxyethyl acrylate / sodium acryloyldimethyltaurate copolymer.

Example 1

In Example 1, the influence of potential stabilizer compounds on the thermal stability of hydrogen peroxide 60% solutions at 75 °C was studied.

Therefore, 50 g of the sample including hydrogen peroxide and a potential stabilizer or a combination of stabilizers was heated in a heat chamber and the gas volume generated at 75 °C over a period of time was measured. Furthermore, at the end of the test a gaseous sample was taken off to determine the volume of generated oxygen (O2) and carbon dioxide (CO2). The O2 and CO2 measurements on the gaseous samples of the tests were carried out to distinguish between oxygen generated by the decomposition of hydrogen peroxide and carbon dioxide generated by the decomposition of organic with hydrogen peroxide.

Test 1

Test 1 was a rapid screen test. At first, the hydrogen peroxide solution ST60 Voikaa was used. The best results obtained in this study were compared with two other hydrogen peroxide solutions - ST Jemeppe and RO 60 LH - having a higher degree of purity.

As stabilizers, the following compounds were tested: DTPMP, L-ascorbic acid, 4-hydroxyphenyl acetic acid, 3 -hydroxybenzoic acid, 2-picolinic acid, 8-hydroxyquinoline, phenacetin, DPA, gallic acid, tannic acid, stannate, SAPP, isophthalic acid, a combination of DPA and stannate, and a combination of DPA and DTPMP.

Isophthalic acid, although it is not known as hydrogen peroxide stabilizer, was used, because its structure is very similar to DPA with the two -COOH groups in the meta position on an aromatic ring and thus may be a suitable stabilizer for hydrogen peroxide.

For each sample, the stabilizer compound was added to hydrogen peroxide solution in an amount of 100 ppm.

Further samples of DPA, wherein DPA was used in an amount of 200 ppm and 500 ppm were tested. DTPMP was used also in an amount of 50 ppm, 100 ppm, 200 ppm and 500 ppm in the samples.

In Test 1, the samples were exposed to a temperature of 75°C for 6 hours to determinate the stabilization effectivity of the compounds, i.e. which compound considerably reduces the degradation of hydrogen peroxide solution compared to the un-stabilized hydrogen peroxide solution.

Results

• All samples showed a linear decomposition of hydrogen peroxide over the duration of the test and thus a certain stability.

• Isophthalic acid did not provide a stability effect on hydrogen peroxide.

• Stannate and SAPP are alone were not very effective.

• DTPMP showed the desired stability effect, in particular in a concentration range of 50 to 200 ppm. Furthermore, it was found that it is beneficial when an amount of 500 ppm of DTPMP is not exceed. The optimal concentration of DTPMP is 200 ppm.

• Dipicolinic acid and 2-picolinic acid gave also good results, whereby an increasing of the concentration of dipicolinic acid from 100 to 500 ppm did not change the effect.

• The combination of dipicolinic acid and DTPMP provided the best stability effect on hydrogen peroxide for all three grades of hydrogen peroxide 60% solutions. The decomposition of hydrogen peroxide was reduced by a factor of 10 compared to the sample including ST60 Voikkaa without stabilizer. Test 2

In Test 2, the seven samples showing the best results in Test 1, i.e. which reduce the degradation of hydrogen peroxide solution compared to the unstabilized hydrogen peroxide solution effectively, were tested to confirm that the stabilizer are suitable to stabilize hydrogen peroxide over a longer period. Therefore, the samples were exposed to a temperature of 75 °C for 24 hours.

The seven samples were

• RH60 LH

• ST 60 Voikkaa + 100 ppm DPA

• ST 60 Voikkaa + 500 ppm DPA

• ST 60 Voikkaa + 200 ppm DPA + 100 ppm stannate

• ST 60 Voikkaa + 200 ppm DPA + 100 ppm DTPMP

• ST60 Jemeppe + 200 ppm DPA + 100 ppm DTPMP

• RO60 LH + 200 ppm DPA + 100 ppm DTPMP

Results

The results of the Test 2 are depicted in Figure 1.

As can be seen from this Figure:

• RO60 LH without stabilizer shows an acceleration of decomposition after 6 hours.

• The measured decompositions is linear for the other 6 samples over 24 hours.

• The combination of DPA and stannate does not provide a sufficient stability over a longer period of time.

• An amount of DPA between 100 and 500 ppm is sufficient to obtain the desired stability effect.

• The combination of DPA and DTPMP provides the best stability effect for all three grades of hydrogen peroxide 60 % solution.

Test 3

In Test 3 the following samples were used

• ST 60 Voikkaa + 500 ppm DPA

• ST 60 Voikkaa + 200 ppm DPA + 100 ppm DTPMP

• ST60 Jemeppe + 200 ppm DPA+ 100 ppm DTPMP

• RO60 LH + 200 ppm DPA + 100 ppm DTPMP

The samples were exposed to a temperature of 75 °C for 48 hours. Results

This test confirmed that a combination of DPA and DTPMP improves the stability of the hydrogen peroxide solution in a sufficient manner.

Conclusion

The combination of DPA and a phosphonic acid compound (e.g. DTPMP) stabilizes a hydrogen peroxide solution, in particular a concentrated hydrogen peroxide solution, in a sufficient manner.

Example 2

In Example 2, the compatibility of the gelling polymers with hydrogen peroxide 60 % solution was studied. In order to limit additional decomposition of hydrogen peroxide on contact with the polymer, care was taken that the addition of the polymer did not increase the pH of the solution or that the polymer did not degrade or very little in contact with the hydrogen peroxide. The following samples were tested.

• RO60 LH + Guar

• RO60 LH + PEG

• RO60 LH + Pluronic® F 127

• RO60 LH + Tylose®

• RO60 LH + poly (methyl methacrylate)

• RO60 LH + Pluronic® F127 + 100 ppm 2-picolinic acid

• ST60 Voikkaa + Pluronic® F127 + 200 ppm DPA + 100 ppm DTPMP

• ST60 Voikkaa + Sepineo® P600 + 200 ppm DPA + 100 ppm DTPMP

• ST60 Voikkaa + Pluronic® F127 + 200 ppm DPA + 100 ppm DTPMP + H3PO4

• ST60 Voikkaa + Sepineo® DERM + 200 ppm DPA + 100 ppm DTPMP + H3PO4

The samples were exposed to a temperature of 75 °C for 6 hours. RO60 LH, which has the highest purity degree, was chosen as hydrogen peroxide solution to observe the influence of the polymer with the least possible interference. The best polymers were then tested with stabilizers. The proportion of polymer in mixture tested was 2%, i.e. 1 g of polymer in 49 g of hydrogen peroxide solution.

Results

The results of Example 2 are depicted in Figure 2. As can be seen from this Figure:

• Guar, PEG, Tylose® and poly(methyl methacrylate) without stabilizer shows a worse compatibility with hydrogen peroxide.

• Pluronic® F127 without any stabilizer shows a certain compatibility, which can be improved by adding a stabilizer (2- picolinic acid) to the sample.

• The best results are obtained by using Pluronic® F127 in combination with a stabilized hydrogen peroxide solution according to the invention.

• Sepineo® with stabilizers shows also a compatibility with hydrogen peroxide. However, this compatibility is less in comparison to the compatibility of Pluronic® F127.

A further stability test was carried out for 48 hours at 75 °C. Also in this test the best results were obtained by using Pluronic® F127 in combination with a stabilized hydrogen peroxide solution of the invention.

Example 3

In this example, reactors used for thermal stability test at 75 °C have been designed in accordance with the standard test method EN-13621-2. The reactor is made of glass, as are cover and thermocouple support. The seal is in PTFE and all connections are plastic. There is a reactor for the reference and two other reactors for measuring the samples.

The complete equipment consists of:

• Three glass reactors, one reactor for the reference and two reactors for the measurements

• 4 temperature probes, 2 probes for the reference and one probe for each of the other reactors

• A ventilated oven

• 3 pressure sensors

• Two overpressure safety valves calibrated to open at 2.5 bar • A recorder for temperature and pressure

Test procedure:

• 100 ml of water is put in the reference reactor (first reactor)

• 100 ml of the sample to be tested is put in the measurement reactor (reactor 2 and 3)

• Afterwards the degassing values is opened and the oven is turned on at 75 °C

• When the temperature inside the reactors is 75 °C, the degassing value is closed, this is the zero time of the test

• The test is stopped after 48 hours

The following samples were tested:

• ST60 Voikkaa + Sepino DERM 4% + 500 ppm DPA+ 200 ppm DTPMP + Pluronic® Fl 27 (reactor 2, pH 1.12)

• ST60 Voikkaa + Sepineo® P600 5 % + 1000 ppm DPA + 200 ppm DTPMP + NasPCU (reactor 3, pH 4.0)

Results

As can be seen from Figure 3, both samples show a thermal stability which is in accordance with the standard test method EN- 13621-2, i.e. the temperature difference during the test is below the tolerated limit of 3 °C (Reactor 2 has a temperature difference of 0.2 °C; reactor 3 has a temperature difference of 0.8 °C). Hence, both samples show the required thermal stability.

However, the addition of Pluronic® F 127, i.e. the addition of a copolymer of propylene glycol and ethylene glycol, to the sample results into an improvement of the thermal stability even though the amount of DPA in this sample is lower than in the sample without Pluronic® F 127. Hence, the use of Pluronic® F 127 results into an improvement of the stability of the gel.

This result is confirmed by measuring the pressure occurred in the sample reactors during the test. As can be seen from Figure 4, the gel without Pluronic® F127 is very unstable instead of the gel including Pluronic® F127.

Summary

The examples demonstrate that the use of a hydrogen peroxide solution stabilized with dipicolinic acid and a phosphonic acid compound in combination with a copolymer of propylene glycol and ethylene glycol results into a stable gel or emulsion.

Claims

C L A I M S

1. Use of hydrogen peroxide solution containing dipicolinic acid and a phosphonic acid compound in combination with a copolymer of propylene glycol and ethylene glycol for the preparation of gels or emulsions.

2. Use of claim 1, wherein the phosphonic acid compound is a compound having the formula

N(CR¹R²PO₃H₂)X, wherein integer x is at least 3 and R¹ and R² are each independently hydrogen or an alkyl group of one to four carbon atoms.

3. Use of claim 1 or 2, wherein the phosphonic acid compound is selected from the group consisting of amino tri(methylene phosphonic) acid, diethylenetriamine penta (methylene phosphonic) acid, hexamethylene diamine tetra(methylene phosphonic) acid, bis hexamethylene triamine penta (methylene phosphonic) acid, and salts thereof.

4. Use of any one of claims 1 to 3, wherein the hydrogen peroxide concentration in the hydrogen peroxide solution is between 40 and

80 wt.-%, preferably between 50 and 70 wt.-%t, most preferably between 55 and 65 wt.-%, based on the total weight of the hydrogen peroxide solution.

5. Use of any one of claims 1 to 4, wherein the hydrogen peroxide solution contains 50 to 500 ppm of dipicolinic acid, preferably 100 to 400 ppm, most preferably 150 to 300 ppm.

6. Use of any one of claims 1 to 5, wherein the hydrogen peroxide solution contains 10 to 400 ppm of phosphonic acid compound, preferably

30 to 300 ppm, most preferably 50 to 200 ppm.

7. Use of any of claims 1 to 6, wherein the copolymer is a copolymer of the formula

HO(C2H4O)b(C3H₆O)a(C2H₄O)bH wherein a is an integer such that the hydrophobe base represented by (CsHeO) has an average molecular weight of from 2700 to 45000 and b is an integer such that the hydrophile portion is represented by (C2H4O) constitutes from 40 to 85 wt.-% of the total weight of the copolymer.

8. Use of any one of claims 1 to 7, wherein the copolymer is present in an amount of 1 to 20 wt.-%, based on the total weight of the gel or emulsion.

9. Use of any one claims 1 to 8, wherein the gel or emulsion contain a further polymer as gelling agent.

10. Use of claim 9, wherein the further polymer is an acryloyldimethyltaurate copolymer, preferably a copolymer of acrylamide / sodium acryloyldimethyltaurate or a copolymer of hydroxy ethyl acrylate and sodium acryloyldimethyltaurate.

11. Gel or emulsion containing hydrogen peroxide, dipicolinic acid, a phosphonic acid compound and a copolymer of propylene glycol and ethylene glycol.

12. Gel or emulsion of claim 10, wherein the copolymer is a copolymer of the formula

HO(C2H4O)b(C3H₆O)a(C2H₄O)bH, wherein a is an integer such that the hydrophobe base represented by (CsHeO) has an average molecular weight of from 2750 to 4000 and b is an integer such that the hydrophile portion is represented by (C2H4O) constitutes from 45 to 80 weight percent of the copolymer.

13. Gel or emulsion of claim 11 or 12, wherein the gel or emulsion contain a further polymer as gelling agent, preferably an acryloyldimethyltaurate copolymer, more preferably a copolymer of acrylamide / sodium acryloyldimethyltaurate or a copolymer of hydroxy ethyl acrylate and sodium acryloyldimethyltaurate.

14. Use of the gel or emulsion of any one of claims 11 to 13 in rock fragmentation.