# US 4,394,198 A · Water-in-oil emulsion explosive composition

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- Number: US 4,394,198 A
- Document ID: US4394198A
- Status: Granted
- Kind: A
- Application number: 06/293,094
- Filed: 1981-08-17
- Granted: 1983-07-19
- Earliest claimed: 1980-08-25
- Assignees: Nippon Oil and Fats Co., Ltd.
- Inventors: Fumio Takeuchi; Masao Takahashi
- Web page: https://patentgrep.com/patent/US4394198A

## CPC

- C06B 47/145: {Water in oil emulsion type explosives in which a carbonaceous fuel forms the continuous phase}
- C06B: EXPLOSIVES OR THERMIC COMPOSITIONS (blasting F42D); MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES (compounds in general C01, C07 or C08; {demolition agents based on cementitious or like materials C04B41/0009})

## Abstract

A water-in-oil emulsion explosive composition having a remarkably improved storage stability in its initiation sensitivity in small diameter cartridges and at low temperatures is disclosed. The explosive composition comprises a disperse phase formed of an aqueous oxidizer solution consisting of (a) ammonium nitrate or a mixture of ammonium nitrate and another oxidizer salt, (b) water and (c) a specifically limited weak acid salt or condensed phosphate; a continuous phase consisting of (d) fuel oil and/or wax; (e) an emulsifier; and (f) hollow microspheres or microbubbles.

## Claims

### Claim 1

A water-in-oil emulsion explosive composition comprising a disperse phase formed of an aqueous oxidizer solution consisting of (a) an inorganic oxidizer salt selected from the group consisting of ammonium nitrate, and a mixture of ammonium nitrate with at least one of sodium nitrate and calcium nitrate, (b) water and (c) at least one member selected from lithium, sodium, potassium, calcium and ammonium salts of weak acid and condensed phosphoric acid; a continuous phase formed of a combustible material consisting of (d) fuel oil and/or wax; (e) an emulsifier; and (f) hollow microspheres or microbubbles.

### Claim 2 (depends on 1)

A water-in-oil emulsion explosive composition according to claim 1, wherein said weak acid is carbonic acid, boric acid, acetic acid, silicic acid or citric acid.

### Claim 3 (depends on 1)

A water-in-oil emulsion explosive composition according to claim 1, wherein said hollow microspheres are glass hollow microspheres, silica hollow microspheres, shirasu hollow microspheres or synthetic resin hollow microspheres.

### Claim 4 (depends on 1)

A water-in-oil emulsion explosive composition according to claim 1, wherein said microbubbles are microbubbles formed by decomposing and foaming a chemical foaming agent or microbubbles formed by mechanically blowing air into a water-in-oil emulsion.

### Claim 5

A water-in-oil emulsion explosive composition, comprising 40-90% by weight of an inorganic oxidizer salt selected from the group consisting of ammonium nitrate, and a mixture of ammonium nitrate with at least one of sodium nitrate and calcium nitrate, 7.45-28% by weight of water, 0.05-15% by weight of at least one of lithium, sodium, potassium, calcium and ammonium salts of weak acid and condensed phosphoric acid, 1-10% by weight of at least one of fuel oil and wax, 0.5-5% by weight of an emulsifier, and hollow microspheres or microbubbles in an amount sufficient for adjusting the density of the emulsion explosive composition to 0.80-1.35.

### Claim 6 (depends on 5)

A water-in-oil emulsion explosive composition according to claim 5, wherein the amount of at least one of lithium, sodium, potassium, calcium and ammonium salts of weak acid and condensed phosphoric acid is 0.1-5% by weight.