US3765966A

US3765966A - Gelled nitromethane composition

Info

Publication number: US3765966A
Application number: US00274118A
Authority: US
Inventors: D Edwards
Original assignee: Commercial Solvents Corp
Current assignee: IMC Chemical Group Inc; Commercial Solvents Corp
Priority date: 1972-07-21
Filing date: 1972-07-21
Publication date: 1973-10-16
Anticipated expiration: 1990-10-16

Abstract

A process for the production of a gelled explosive composition of nitromethane, inorganic nitrate, a water or methanol fluid medium, and gelling agents therefor, comprising mixing said nitromethane and said fluid medium, adding with thorough agitation said inorganic nitrate, a gelling agent for the fluid medium and a cyanoethyl ether of galactomannan gum gelling agent for the nitromethane.

Description

Unite States Patent [19] Edwards [111 3,765,966 [451 Oct. 16, 1973 GELLED NITROMETHANE COMPOSITION [75] Inventor: Donald W. Edwards, Lehighton, Pa.

[73] Assignee: Commercial Solvents Corporation,

Terre Haute, Ind

22 Filed: July 21,1972

21 Appl. No.: 274,118

[52] US. Cl 149/18, 149/21, 149/47,

149/60, 149/62, 149/89 [51] Int. Cl. C06b 7/00, C06b 19/04 [58] Field of Search 149/2, 18, 89

[56] References Cited UNITED STATES PATENTS 3,419,444 12/1968 Minnick ,.l49/89X 5/1972 Jordan 149/89 10/1972 Edwards 149/89 X Primary Examiner-Leland A. Sebastian Att0rneyI-loward E. Post et a].

[5 7] ABSTRACT 7 Claims, No Drawings GELLED NITROMETHANE COMPOSITION BACKGROUND OF THE INVENTION This invention relates to gelled slurry explosive compositions. In a particular aspect, this invention relates to gelled nitromethane-inorganic nitrate slurry compositions and method of preparing same.

It is known from L. R. Jones, U.S. Pat. No. 3,318,741, to provide stable gels of nitromethane by adding from 0.5 to 10 percent or more of a high molecular weight polyoxyethylene and from 0.1 to 5.0 percent of poly(methylvinylether/maleic anhydride).

Aqueous slurries of ammonium nitrate and nitromethane were disclosed by J. J. Minnick, US. Pat. No. 3,4l9,444. Compositions disclosed included 10-90 percent ammonium nitrate, -50 percent water, 5-50 percent nitromethane. According to Minnick, the nitromethane is first gelled by blending 5 percent nitrocellulose (or the agent of Jones) therein. Then, the ammonium nitrate, resin balloon sensitizer, water, and guar gum thickening agent were added. Other suitable thickeners for the aqueous phase included gum arabic, pregelatinized starch and carboxymethyl cellulose.

Recently W. A. Jordon disclosed in U.S. Pat. No. 3,666,577 that cyanoethyl ethers of galactomannan gums having a degree of substitution of 1.9 or more are effective gelling agents for nitromethane in amounts of about 2 percent or more. Jordon suggests the gelled nitromethane is useful in explosives by incorporating therewith an inorganic nitrate and a sensitizing explosive such as TNT.

The above-described processes are essentially twostep wherein the nitromethane is first gelled, then the ammonium nitrate, water and gelling agent therefor are added. This method is disadvantageous because the gelled nitromethane is difficult to blend uniformly with the other ingredients and requires prolonged mixing. There is, therefore, a need for an improved method of blending.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved method for preparing explosive compositions.

It is another object of this invention to provide an improved method for the preparation of gelled nitromethane-inorganic nitrate water-based slurries.

Other objects of this invention will be obvious to those skilled in the art from the description herein.

It is the discovery of this invention to provide a process for the preparation of explosive gels of nitromethane and inorganic nitrate in a fluid medium by the steps of mixing the liquid, i.e., the nitromethane and fluid medium, then adding the solid ingredients, i.e., the inorganic nitrate, a gelling agent for the fluid medium, and a gelling agent for the nitromethane, and mixing thoroughly. Preferably a tetraalkyl titanate crosslinking agent for the nitromethane is also added.

DETAILED DESCRIPTION The process of the present invention is essentially a one-step process. The liquids, i.e., nitromethane and fluid medium, are charged to a kettle, then the solids are added with thorough agitation to provide good mixing. If desired, the solids can be premixed before adding to the solid phase, but no advantage is gained thereby. The mixture initially forms a thick slurry, then after standing for a short time, develops into a gel.

There is ample time for casting or loading into suitable containers.

The nitromethane employed in the practice of this invention is the usual grade of commerce and is used in an amount of about 10-15 percent by weight, preferably l5 percent. The liquid medium is water or methanol, preferably water, and is used in an amount of about 10 percent by weight.

The inorganic nitrate used in the practice of this invention can be either sodium nitrate or ammonium nitrate or a mixture thereof. The ammonium nitrate can be either low density or high density prills or granular ammonium nitrate sold commercially as fertilizer grade. Ground material can also be used. Preferably the particle size is sufficiently small that it passes a 20 mesh screen. When water is used, it can be saturated with ammonium nitrate to provide a portion of ammonium nitrate in solution form, if desired.

The gelling agent employed for gelling the aqueous phase can be any of the gelling agents known in the prior art of which there are many. Preferred gelling agents include guar gum, gum arabic, pregelatinized starch and carboxymethyl cellulose. Guar gum is preferred. When methanol is used as the fluid medium, the preferred gelling agent is methyl cellulose.

The gelling agent employed for gelling the nitromethane is a cyanoethyl ether of a galactomannan gum having a degree of substitution of greater than 1.9, as disclosed by W. A. Jordon, U.S. Pat. No. 3,666,577 which is incorporated herein by reference. This material is sold by General Mills, Inc. as GM-5l2.

The gels prepared with the foregoing ingredients have sufficient stability for most applications but they begin to break down after several weeks. Firmer and more stable gels can be obtained by cross-linking the GM-5 l2 gelling agent with a tetraalkyl titanate, e. g. tetraisopropyl or tetrabutyl titanate. These compounds are commercially available and the usual commercial grades are suitable for the practice of this invention. Tetraisopropyl titanate is somewhat faster than tetrabutyl titanate, but use of the latter permits longer working time, e.g. for casting or loading into containers.

The nitromethane-inorganic nitrate gel is rendered detonable by shock by incorporating therein a sensitizer, many of which are known, as described by Minnick, U.S. Pat. No. 3,419,444. Preferred sensitizers are glass or resin microballoons.

The practice of this invention will be better understood with reference to the following examples. It is understood that the examples are intended only to illustrate the practice of the invention and it is not intended that the invention be limited thereby.

EXAMPLE 1 To a mixing kettle were charged the following liquid ingredients:

Nitromethane 15.00 lb Aqueous ammonium nitrate Soln., 20.00 50% wt.

The following solid ingredients were added thereto with mixing:

Ammonium nitrate, granular l/l6" 60.l0 lb Glass microballoons 2.00 Cross-linking agent 2.00 GM-5 l2 gelling agent 0.50 Guar gum gelling agent 0.40

EXAMPLE 2 The experiment of Example l was repeated in all es sential details except that the solid ingredients were premixed before adding to the liquids. The mixture formed a thick slurry which became a firm gel after standing a short period of time. It was detonable by the shock of a No. 6 blasting cap.

EXAMPLE 3 To a mixing kettle were charged the following liquid ingredients:

10.0 lb l0.0

Nitromethane Methanol The following ingredients were added with mixing:

Sodium nitrate 10.0 lb Ammonium nitrate 64.7 Glass microballoons 3.0 Cross-linking agent 1.5 Methyl cellulose 0.4 GM-5l2 gelling agent 0.4

The mixture initially formed a thick slurry which became a firm gel after standing a short period of time. It was detonable by the shock of a 10 g booster of pentolite combined with a 6 blasting cap.

The methyl cellulose was Methocel 65 H-6 manufactured by Dow Chemical Company, Midland, Michigan. 4

EXAMPLE 4 The experiment of Example 3 was repeated in all es sential details except that the nitromethane content was increased to 15 lb instead of 10, and the ammonium nitrate content was decreased to 59.7 lb from 64.7.

The resultant gel was detonable by a 10 g booster and a 6 blasting cap.

The glass microballoons used in the foregoing examples are hollow spheres of sodium borosilicate glass, 10-300 microns in diameter, manufactured by Emerson and Cuming, Inc., Canton, Massachusetts.

I claim:

1. In a process for the production of a gelled explosive composition of nitromethane, an inorganic nitrate, a water or methanol fluid medium and gelling agents therefor, the improvement consisting of adding to a mixture of said nitromethane and said fluid medium, with thorough agitation, a mixture of said inorganic nitrate, a gelling agent for the fluid medium and a cyanoethyl ether of galactomannan gum gelling agent for the nitromethane.

2. The process of claim 1 wherein said inorganic nitrate is ammonium nitrate.

3. The process of claim 1 wherein said inorganic nitrate is a mixture of sodium nitrate and ammonium nitrate.

4. The process of claim 1 wherein said fluid medium is water.

5. The process of claim 1 wherein said fluid medium is methanol.

6. The process of claim 1 wherein said fluid medium is water saturated with ammonium nitrate.

7. The process of claim 1 wherein additionally a tetraalkyl titanate cross-linking agent for the cyanoethyl ether of galactomannan gum is incorporated therewith in said composition.

* g;;g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent {765 966 I Dated October 16, 1973 Inven fl Donald W. Edwards lt is certified that eirror appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 24, "Jordon" should be -Jordan-' Column 2, line 29, "Jordon" should be -Jordan-- Colunm 3, line 38, "a 6" should be --a #6 Column 4, line 9 "a 6" should be --a #6-' Signed and sealed this 9th day of April 19m.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer v Commissioner of Patents 22 3 33 C UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 1165 966 Dated October 16, 1973 Invent fl Donald W. Edwards 7 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 24, "Jordon" should be Jordan-' Column 2, line 29, "Jordon" should be -Jordan- Column 3, line 38, "a 6" should be a- #6 Column 4, line 9, "a 6" should be a #6-- Signed and sealed this 9th day of April 197i;

(SEAL) Attest:

EDWARD M.FLETCHER,JR. G. MARSHALL DANN Attesting Officer Commissioner of Patents

Claims

2. The process of claim 1 wherein said inorganic nitrate is ammonium nitrate.
3. The process of claim 1 wherein said inorganic nitrate is a mixture of sodium nitrate and ammonium nitrate.
4. The process of claim 1 wherein said fluid medium is water.
5. The process of claim 1 wherein said fluid medium is methanol.
6. The process of claim 1 wherein said fluid medium is water saturated with ammonium nitrate.
7. The process of claim 1 wherein additionally a tetraalkyl titanate cross-linking agent for the cyanoethyl ether of galactomannan gum is incorporated therewith in said composition.