NZ206183A - Emulsion explosives containing lanolin - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £06183 2061 3 Priority Date(s): 'S- //- Complete Specification Filed: Class: co6&j/<?o..Co6$fr/o?tz& A <>£ 8 .<??,. M J23 JAN W Publication Date: P.O. Journal, No: . #.?/ NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION AN EXPLOSIVE IN THE FORM OF AN EMULSION X/We, AECI LIMITED of 16th Floor, Office Tower, Carlton Centre, Commissioner Street, Johannesburg, Transvaal Province, Republic of South Africa, a company incorporated under the laws of South Africa, hereby declare the invention for which k/ we pray that a patent may be granted to KJe^us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 80 61 83 THIS INVENTION relates to an explosive. In particular the invention relates to an explosive of the emulsion type in which an oxidising salt-containing component forms the discontinuous phase in an emulsion wherein the continuous phase comprises a fuel component which is immiscible with the discontinuous phase.

Such explosives, where the oxidising salt-containing component contains water and is in the form of an aqueous solution are known as "water-in-fuel" emulsions, and when the oxidising salt component includes no water they can be regarded as "melt-in-fuel" emulsions.

According to the invention there is provided an explosive in the form of an emulsion comprising a discontinuous phase which includes an oxidising salt; and a continuous phase which includes a fuel which is immiscible with the discontinuous phase, and wherein there is lanolin which acts as an emulsifier or as a co-emulsifier, and as an emulsion stabiliser.

N J * 2 061 S3 The lanolin functions by increasing the stability of the explosive material against breakdown of the emulsion, and further acts as an emulsifier to assist in formation of the emulsion.

The emulsion is formed by dispersing the discontinuous phase in the continuous phase when they are both in liquid form, but the expression "emulsion" is intended to be construed as covering also the emulsions at temperatures below that at which they were formed, so that the discontinuous phase may be a sol id.

The Applicant has found that crude or unrefined lanolin is an effective emulsifier without contributing substantially to the stability of the emulsion, but with increasing purity it has an increasing effect in prolonging the stability of the emulsion formed, lanolin of B.P. grade purity or better being effective in this regard. Thus, crude lanolin can provide an emulsion with a stability of 11 weeks or more, sufficient for bulk uses of explosives, whereas B.P. grade lanolin can provide an explosive which can be stored at 40°C for 25 weeks or more. While the use of excessive quantities of lanolin can prevent the formation of an emulsion, the Applicant has found that the use of effective proportions thereof, from 0,05% up to 1,5% by mass, can lead to effective emulsification and enhanced stability. mhe oxidising salt may include a member selected from the group consisting of: alkali metal nitrates, alkali metal perchlorates, alkaline earth metal nitrates, alkaline earth metal perchlorates, ammonium nitrate, ammonium perchlorate, and mixtures of two or more thereof ^he oxidising salt may be present as an acrueous solution .

Instead, the discontinuous phase may include ammonium nitrate and one or more compounds which, together with the ammonium nitrate, form a melt which has a melting ooint which is lower than that of the ammonium nitrate, the compounds being capable of acting as oxygen releasing salts or fuels.

The fuel may form from about 2 to 2 5% by weight of the emulsion, preferably being in the region of about 3 to 12% by weight thereof.

The fuel may include an emulsifier, or a mixture of suitable emulsifiers. • rs* -5- 206 j 82 Emulsifiers which can be used as co-surfactants together with lanolin include members selected from the group consisting of sorbitan sesquioleate, sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, the 5 mono- and diglycerides of fat-forming fatty acids, soya bean lecithin, alkyl benzene sulphonates, oleyl acid phosphate, laury-lamine acetate, decaglycerol decaoleate, decaglycerol decastea-rate, polymeric emulsifiers containing polyethylene glycol back bones with fatty acid side chains, and suitable mixtures of two or more thereof. ft The fuel will be immiscible with and insoluble in water, and is preferably a non-self-explosive organic fuel, being for example selected from the group consisting of hydrocarbons, halo-genated hydrocarbons and mixtures thereof. Thus the fuel may 15 comprise a member selected from the group consisting of mineral oils, fuel oils, lubricating oils, liquid paraffin, microcrystal-line waxes, paraffin waxes, xylene, petrolatum, toluene, dinitro-toluene and mixtures of two or more thereof.

An energetic solid fuel such as atomised aluminium may also be included.

The emulsifiers act as stabilisers to promote the formation of the emulsion and to stabilise the emulsion by combatting coalescing and/or crystallisation of the discontinuous phase.

X I 20618 3 In qeneral when the discontinuous phase contains water, this water should be kept at a minimum consistent with forminq a satisfactory emulsion and the prevention of wasted energy from steam production upon detonation. © ' ^he density of the emulsion will be such as to form a suitable explosives composition, and preferably may be between 1,30 g/ml and 1,50 cr/ml (ie 1, 30kg//, and l,50kq/^) at 25°C.

O ^he explosive may thus include a density reducing agent to provide the emulsion with a desired density of say 1,10 to 10 1,15 g/ml (ie 1,10 to l,5ka/J_, ) at 25 °C. "he emulsion may comprise up to 3% and preferably 1,5 to 3,0%, by mass of the density reducinq agent, which may be of glass or a polymeric material. The density reducing agent will also act to sensitise the explosive. The density reducing agent may comprise microballoons for example.

O O ^he following emulsions were prepared and used as control emulsions: CONTROL EMULSION NO. 1 ^he formulation of this emulsion was as follows: % BY MASS Ammonium Nitrate Sodium Nitrate Calcium Nitrate Water 25 P95 Oil Sasolwaks M Microcrvsta11ine Wax 0632 62, , 00 3, 70 12, 90 1, 1, 65 1, 65 0 ij | C: Arlacel 83 Soya Lecithin A surfactant C15/250 Glass Microballoons 0, 72 0, 72 0, 31 (added subseauentlv in a proportion eouivalent to 3% of the above formulation to obtain a final density of 1,10 - 1,15 kg/J^ ) P95 Oil is a paraffinic hvdrocrabon fuel available from BP Southern Africa (Proprietary) Limited; Rasolwaks M is a hydrocarbon wax fuel available from Sasol Marketing Company Limited; Microcrystalline Wax 0632 is a hvdrocrabon wax fuel available from Rasol Marketina Company Limited: Arlacel 83 is a sorbitan sesquioleate emulsifier available from Atlas Chemical Company; The surfactant is a suitable polymeric emulsifier of a type typically employed for this purpose; and C15/250 microballoons are those available from 3M (South Africa) (Proprietary) Limited.

The emulsion was prepared in a Hobart mixer having a steam jacketed bowl with a wire whip according to the following standard method: The oil phase was heated to 85°C and poured into the steam jacketed bowl. With the wire whip rotating at a speed of 285 rpm, the aoueous phase (i.e. the oxidising salts and water) was added to the oil phase at a temperature of 85°C. The resultant emulsion was stirred for another two minutes at the same speed, which was then increased to 591 rpm for a period of 10 -V. 2 0 6183 6 o minutes. After this the product had a petroleum-jelly like consistency and a density of 1,45 g/ml (ie 1,45 kg//, ). The glass microballoons were added at 65°C to bring the density down to 1,10 - 1,15 g/ml (ie 1,10 - 1,15 kg/Jb ). —4 The emulsion detonated with 0,36g (ie 3,6x10 kg) of nentaervthritol tetranitrate (hereinafter referred to as PFmN) at 25°C in 25rnr! (ie 2,5x10 ^m) diameter after 10 weeks storage at 40°C and after 11 months storage at ambient temperature but could not be detonated in the same fashion after 12 weeks storage at 40°C and after 12 months storage at ambient temperature.

CONTROL EMULSION MO.

The formulation of this emulsion differed from that of the control emulsion No. 1 in that the oil and wax components thereof were replaced with an equivalent amount of unprocessed 15 petrolatum, and this emulsion was prepared via the same method as described above for the control emulsion No. 1.

The emulsion detonated with 0,36g (ie 3,6x10 "kg) of PF.TN at 25°C in 25 mm (ie 2,5x10 ^m) after 12 weeks storage at 4 0°C and 20 weeks storage at ambient temperatures, and these 20 tests are still in progress so that the maximum storage periods have not yet been established. - 206183 J — O — | ^he invention will now be described, with reference ^ to the following non-limiting exanples: SAMPLE 1 An emulsion was prepared in accordance with the procedure des-cribed for the control emulsion No. 1, except that the surfactant --►"Jar' used was 0,31% m/m of B.P. grade lanolin. This emulsion was -2 found to detonate in 25mm (ie 2,5x10 m) diameter with 0,36 a (ie 3,6x10 ^kg) PE'T'N at 25°C after 19 weeks storage at 1^) 40°C, 40 weeks at ambient temperatures, and 40 weeks at - 17°C, and these tests are still in progress.

EXAMPLE 2 Example 1 was prepared with 0,55% m/m B.P.grade lanolin, 0,55% soya lecithin, and 0,65% Arlacel 83. The emulsion was found to detonate in the sane fashion after 12 weeks storage at 40°C and 15 after 30 weeks storage at ambient temperatures, and these tests are still in progress.

EXAMPLE 3 O Example 1 was repeated with 0,875% m/m Arlacel 83, no soya lecithin at all, and 0,875% m/m B.P. grade lanolin. This emulsion 2o was found to detonate in the same fashion after 1-2 weeks storage u at 40°C and after 11 weeks storage at ambient temperatures, and these tests are still in Drooress. 206183 EXAMPLE 4 Example 1 was repeated using no Arlacel 83 and no soya lecithin, but with 1,75% m/m B.P. grade lanolin. No emulsion could be formed.

EXAMPLE 5 Example 1 was repeated using a lanolin alcohol fraction (which included sterols) in place of the surfactant. The emusion was found to detonate in the same fashion after 1* weeks storage at and these tests are still in nrogress. 40 C EXAMPLE 6 Example 1 was repeated using a lanolin sterol fraction in place of the surfactant. The emulsion was found to detonate after 10 weeks storage at 40°C, and these tests are still in progress.

EXAMPLE 7 An emulsion was prepared in accordance with the procedure described for the control emulsion No. 2, except that the surfactant used was 0,31% m/m of technical grade lanolin. This emulsion was found to detonate in 25mm (ie 2,5x10 ^m) diameter with 0,36g (ie 3,6x10 kg) PETN at 25°C after 19 weeks storage at 40°C and 20 weeks storage at ambient temperature, and these tests are still in progress.

Lanolin is a completely natural oroduct containing a plurality of constituents, whose proportions can vary depending on the source of the lanolin, the methods, if any, used to purify it, and its degree of purity. In accordance with the present invention lanolin as a whole has been found to act as an emulsi- A" • \ -u" 206183 I I | fying and stablizing surfactant, but the applicant believes that 1 certain of its constituents, or combinations thereof, may contri- | bute more to its properties in this regard than others. Lanolin consists mainly of esters composed of aliphatic alcohols, triter 5 pene alcohols, and sterols combined with fatty acids. It also contains fractions comprising free alcohols (including sterols), 0) fatty acids and hydrocarbons. It is believed that the alcohols, the fatty acids and sterols including cholesterol may contribute to the emulsifying power of the lanolin. The esters alone do not 10 have emulsifying properties, but are believed to enhance the ; emulsifying oroperties of the alcohols and sterols. ^he alcohols and sterols may contribute to the stabilising power of the lanolin, either alone or in combination. When used with lanolin esters, the stabilising power of the alcohols and sterols may 15 synergistically increase. ^hus the applicant believes that the alcohols together with the esters and/or the sterols together with the esters will have substantial utility in the context of the present invention.

The invention thus extends to said lanolin alcohol frac-0 tions and lanolin sterol fractions and mixtures thereof with lanolin esters for use as an emulsifier or co-emulsifier and as an emulsion stabiliser in emulsion explosives of the type described. Consequently the aforegoing description in respect of the lanolin applies equally to such fractions of lanolin and to 25 such mixtures thereof. •fl# Advantages of the invention, at least as exemplified, include the relatively low cost of lanolin as compared to emulsions of the type typically used in these circumstances. in certain cases, for example in Example 1, lanolin appears to enhance the stability of the explosive and shows promise that it may exceed the usefulness of common, conventional surfactants in many cases. 2 0 6 | & 206183

Claims (21)

WHAT WE CLAIM IS:

1. An explosive in the form of an emulsion which a discontinuous phase which includes an oxidising a continuous phase which includes a fuel which is ible with the discontinuous phase, and wherein there which acts as an emulsifier or as a co-emulsif ier, emulsion stabiliser.

2. An explosive as claimed in Claim 1 wherein the lanolin constitutes 0.05 to 1,5% by mass of the emulsion. includes salt; and immis-is lanolin and as an

3. An explosive as claimed in Claim 1 or Claim 2 wherein the oxidising salt includes a member selected from the group consisting of: alkali metal nitrates, alkali metal perchlorates, alkaline earth metal nitrates alkaline earth metal perchlorates, ammonium nitrate, ammonium perchlorate, and mixtures of two or more thereof.

4. An explosive as claimed in any one of the preceding claims, wherein the oxidising salt is present as an aqueous solution. »4nwim ... J .)

5. An explosive as claimed in Claim 3, wherein the discontinuous phase includes ammonium nitrate and a compound which, together with the ammonium nitrate, forms a melt which has a melting point which is lower than that of the ammonium nitrate, the compound being capable of acting as an oxygen releasing salt or fuel.

6. An explosive as claimed in any one of the preceding claims, wherein the fuel forms 2 to 25% by weight of the emulsion . 10

7. An explosive as claimed in any one of the preceding claims, wherein the fuel is organic and non-self-explosive.

8. An explosive as claimed in Claim 7, wherein the fuel includes a member selected from the group consisting of mineral oils, fuel oils, lubricating oils, liquid parafffin, micro-cry-12 stalline waxes, paraffin waxes, xylene, petrolatum, toluene, dinitrotoluene, and mixtures of two or more thereof.

C3 An exPl°s^-ve as dairoed in any one of the preceding claims which includes a solid fuel.

10. An explosive as claimed in Claim 9 wherein the solid u fuel is atomised aluminium. "TMETTT - 15 - 20© YZZ

11. An explosive as claimed in any one of the preceding claims in which the fuel includes an emulsifier.

12. An explosive as claimed in Claim 11, wherein the emulsifier comprises a member selected from the group consisting of sorbitan sesquioleate, sorbitan monooleate, sorbitan mono-palmitate, sorbitan monostearate, sorbitan tristearate, the mono- -and diglycerides of fat-forming fatty acids, soya bean lecithin, derivatives of lanolin, alkyl benzene sulphonates, oleyl acid phosphate, laurylamine acetate, decaglycerol decaoleate, decaglycerol decastearate, polymeric emulsifiers containing polyethylene glycol backbones and fatty acid side chains and suitable mixtures of two or more thereof.

13. An explosive as claimed in any one of the preceding claims, wherein the density of the emulsion is from 1,30 g/ml to 1,50 g/ml (ie 1.30 to 1,50 kg/X ) at 25°C.

14. An explosive as claimed in any one of Claims 1 to 12, which includes a density reducing agent.

15. An explosive as claimed in Claim 14, which has a density of 1.10 to 1.15 g/ml (ie 1.10 to 1.15 kg/£, ) at 25°C.

16. An explosive as claimed in Claim 14, or Claim 15, wherein the density reducing agent is of glass or polymeric material - 16 - 206183

17. An explosive in the form of an emulsion, which includes a discontinuous phase v/hich includes an oxidising salt; and a continuous phase which includes a fuel which is immiscible with the discontinuous phase, and wherein there is a lanolin 5 alcohol fraction which acts as an emulsifier or co-emulsifier and as an emulsion stabiliser. Q

18. An explosive as claimed in Claim 17, which includes lanolin esters together with the lanolin alcohol fraction. O

19. An explosive in the form of an emulsion, which includes 10 a discontinuous phase v?hich includes an oxidising salt; and a continuous phase which includes a fuel v/hich is immiscible with the discontinuous phase, and wherein there is -a lanolin sterol fraction which acts as an emulsifier or co-emulsifier and as an emulsion stabiliser. 15

20. An explosive as claimed in Claim 19 which includes lanolin esters together with the lanolin sterol fraction.

21. An explosive as defined according to any one of claims 1 to 20 inclusive substantially as herein described and exemplified. DATED THIS 3^ DAY OF 19 ^ A. J. PARK a SON PER AGtf.'TS TOR THE /.~?UCANTS