Packaged explosive

[57] ABSTRACT

A skin-tight explosive not having an air space or sag, and a method of making it. An explosive containing a plasticizer-extractor is placed in a flexible polyvinyl chloride bag which has been plasticized with an extractable plasticizer. The air space or sagging bag which would normally form is eliminated due to the shrinkage of the bag.

Claims, 1 Drawing Figure

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ΡΛΓΕΝΤΕϋΗΛΥ 81973 3,731,625

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INVENTOR

Frank E. Slawinskl

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ATTORNEY

3,731,625

PACKAGED EXPLOSIVE

Many explosives must be heated during their manufacture. They are usually immediately placed in a package and sealed. This procedure frequently causes the bag to wrinkle and sag or causes an air space to form at the top of the package due to contraction of the explosive as it cools. An air space or sag may also result due to the rearrangement of particles to mate better as they settle. This frequently happens when AN-FO (ammonium mitrate - fuel oil) is packaged, which is done at ambient temperatures. The air space or sag may also be caused by the coalescence of gases dissolved in the explosive or the absorption of gases into solid particles and this, too, may occur at ambient temperatures.

The presence of an air space or sag in the package is unattractive, which makes the product less salable, and an air space may prevent the propagation of the explosion from one container to the next when they are stacked in a borehole.

I have discovered a skin-tight explosive package and a method of making it. Due to an interaction between the container and the explosive, the container shrinks with the explosive forming a skin-tight package with no air space or sag. A flexible polyvinyl chloride (PVC) film is plasticized with an extractable plasticizer and formed into a bag. An explosive which contains a plasticizer-extractor; preferably a solvent for the plasticizer such as most oils, is placed in the bag and the bag is sealed. Gradually, the bag shrinks as the plasticizer in the bag is allowed to be extracted into the plasticizer-extractor in the explosive which may migrate through the plastic to form a light film on the bag.

In addition to the elimination of the air space and sag, the packaged explosive of this invention has superior elasticity, toughness, and memory which enable it to be dropped into boreholes containing water without rupturing. The shrinkage of the polyvinyl chloride bag also puts pressure on the explosive which may cause the particles in an explosive such as AN-FO to rearrange themselves to give the explosive a higher density. This may be desirable as it will enable the explosive to sink better in a water-filled borehole.

The accompanying drawing is a side view of a certain presently preferred embodiment of this invention.

In the drawing, a sheet of flexible polyvinyl chloride which has been plasticized with an extractable plasticizer is formed into a tube 1 by making a side lap seal 2. One end of the tube is tied with a cord 3 to form a bag and the bag is filled with an explosive 4 containing a plasticizer-extractor. The other end of the bag is then sealed by tying it with a second cord 5 to form the packaged explosive. 55

While the packaged explosive of FIG. 1 is preferred because of its strength, low cost, and ease of manufacture, other types of bags may also be used. Examples include blow-molded shells, seamless tubing, vacuumdrawn containers, and spiral-wound shells. The bag ⁶⁰preferably is cylindrical and has a diameter of about 1 to 12 inches and a length of about 6 to 45 inches.

Although the polyvinyl chloride may be of any flexible thickness, a thickness of at least about 4 mils and up to about 50 mils is generally suitable. Preferably, for the best explosive packages, the thickness should be between about 6 and about 20 mils.

The polyvinyl chloride bag is plasticized with a sufficient amount of an extractable plasticizer to (1) obtain the desired degree of shrinkage when the plasticizer is in part extracted and (2) leave enough plasticizer unex5 traded to keep the bag flexible. I have found that the amount of plasticizer in the polyvinyl chloride should be about 20 to about 60 percent (all percentages herein are by weight) of the polyvinyl chloride to obtain the best results.

¹⁰ The plasticizer must be extractable. Examples of plasticizers which are extractable in mineral oil and most other oils and are therefore preferred include dioctyl phthalate, diisooctyl phthalate, diisodecyl phthalate, trichloroethyl phosphate, trioctyl phosphate, tri-2-ethylhexyl phosphate, octyl-diphenyl phosphate, decyl-diphenyl phosphate, cresyldiphenyl phosphate, tricresyl phosphate, dioctyl adipate, polyethylene glycol di-2-ethyl-hexoate, and mixtures thereof. Cer₂₀ tain alkyl aryl phosphates may also be used. Table 1 gives the percent that various plasticizers were extracted from a film after the film was soaked in S.A.E. 20 oil for 10 days at 23°C.

TABLE 1

Plasticizer

Dioctyl phthalate

Tri-2-ethylhexyl phosphate (|C₄H_eCH(C₂H₅ CH₂O]₃P = 0) sold 30 under the trademark “Flexol

TOF” by Carbide and Carbon Chemicals Co.

Octyl-diphenyl phosphate sold under the trademark “Santicizer 1.41 ” by Monsanto Chemical ^C° ^{J J} Tricresyl phosphate

Dioctyl adipate

Polyethylene glycol di-2-ethylhexoate (CrHnCOOCHafCFh OCHthCHsOCOCrH») sold under the trademark “Flexol

4GO” by Carbide and Carbon Chemicals Co.

A high-boiling liquid, sp. gr. 0.9564, boiling point 255°C. (5 mm. Hg), flash point 420°F., practically insoluble in water, sold under the trademark “Flexol 8N8” by Carbide and Carbon Chemicals Co.

Extracted 17.3

29.1

14.1

6.3

20.6

25.2

12.8

The above table was in part obtained from “The Stabilization of Polyvinyl Chloride” by Chevassus Broutilles, page 263.

Table 2 gives the percent extractability in mineral oil of various phthalate plasticizers. The plasticizer concentrations are at 50 parts per hundred of resin.

TABLE 2

Phthalate % Extractable

Dioctyl[ θ

Diisooctyl13

Diisodecyl24

Various linear phthalates made from Conoco, Ethyl, and Monsanto alcohols 3.4 to 5.1

The above table was obtained from the November, 1970 issue of “Modern Plastics,” page 78.

Table 3 gives the percent extraction of various plasticizers in kerosene. A 40 mil PVC film was used with a plasticizer concentration of 67 p.h.r. (parts per hundred of resin).

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4

TABLE 3

Plasticizer ί % Extraction

Dioctyl phthalate34

Trichlorethyl phosphate6.7

Trioctyl phosphate74

Octyl-diphenyl phosphate¹7.3

Decyl-diphenyl phosphate²6.7

Cresyl-diphenyl phosphate2.1

Tricresyl phosphate1.3

1. Sold by Monsanto Chemical Co. under the trademark “Santicizer 141.’’

2. Sold by Monsanto Chemical Co. under the trademark “Santicizer 148.’’

The above table was obtained from the Jan. 29, 1971 issue of “Chemscope,” page 18. The differences in extractability of dioctyl phthalate between Tables 1, 2, and 3 may be due to experimental differences such as the amount of plasticizer originally in the film.

At least about 0.1 percent of the plasticizer should be extracted to obtain a noticeable amount of shrinkage. Preferably, about 3 percent to about 40 percent of the plasticizer is extracted to obtain a significant amount of shrinkage without leaving the polyvinyl chloride bag inflexible and brittle.

Table 4 gives the percent contraction of 7 MD (machine-direction) by 5 CD (cross-direction) sheets of PVC film after 1 week and 1 month of immersion in various solvents, primarily oils. “KDA-2076” is a product designation of Union Carbide for a 12 mil PVC film plasticized with 33.5 percent dioctyl phthalate and having a density of 1.225 gms./cc. “KDA-2109” is a Union Carbide product designation for a 20 mil PVC film having a density of 1.215 gms./cc. plasticized with 33.8 percent “Flexol 10—10” (a Carbide and Carbon Chemicals Co. trademark for diisodecyl phthalate).

<td></td><td> Rustoleum</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td></td><td> Thinner⁴¹</td><td> 6.3</td><td> 6.2</td><td> 7.1</td><td> 7.6</td><td> 5.4</td><td> 7.6</td><td> 7.1</td><td> 7.6</td>

<td></td><td> Rabtex⁷</td><td> 0.4</td><td> 0.6</td><td> 1.9</td><td> 1.2</td><td> 0.0</td><td> 0.6</td><td> 0.8</td><td> 0.6</td>

<td></td><td> Safflower Oil</td><td> 3.6</td><td> 3.8</td><td> 5.4</td><td> 5.0</td><td> 2.7</td><td> 3.8</td><td> 4.4</td><td> 5.6</td>

<td></td><td> Soybean Oil</td><td> 3.1</td><td> 3.2</td><td> 4.4</td><td> 5.0</td><td> 2.7</td><td> 3.8</td><td> 4.4</td><td> 5.6</td>

<td></td><td> Actinol’¹</td><td> 3.6</td><td> 4.4</td><td> 4.4</td><td> 5.0</td><td> 4.0</td><td> 3.8</td><td> 4.4</td><td> 5.0</td>

<td> 5</td><td> Turpentine</td><td> 5.4</td><td> 6.2</td><td> 6.3</td><td> 6.8</td><td> 5.4</td><td> 6.2</td><td> 7.1</td><td> 7.6</td>

1. Texaco, inc., trademark for lubricating oil.

2. Atlantic Richfield Co. trademark for mineral oil.

3. Witco Chemical Co. trademark for mineral oil.

4. Texaco. Inc., trademark for lubricating oil.

5. Atlantic Richfield Co. trademark for lubricating oil

6. Rustoleum Corp, trademark for fish oil.

7. Texaco, Inc., trademark for lubricating oil.

8. Arizona Chemical Co. trademark for a fatty acid fraction of tall oil.

Fuel oil, mineral oil, lubricating oil, kerosene, nitroalkanes from C, to C₃, and nitroglycerins are preferred as they are the most useful in formulating explosives.

Table 5 shows the percent contraction of 5” CD by 7 MD sheets of PVC film immersed for various periods of time at 70°F. and 90°F. in a mineral oil sold under the trademark “Atreol 34” by the Atlantic Richfield Co. “KDA-2O3O” is Union Carbide’s product designation for 8 mil PVC plasticized with 33.7 percent dioctyl phthalate and having a density of 1.237 gms./cc. “KDA-2078” is Union Carbide’s product designated for 12 mil PVC plasticized with 30 percent dioctyl phthalate and having a density of 1.251 gms./cc. “³⁰ Toywrap” is Transilwrap Co.’s product designation for 2-mil plasticized PVC.

TABLE

<td></td><td colspan="3"> TABLE4 “KDA</td><td> -2076”</td><td colspan="3"> “KDA-2109”</td><td>³⁵ Film</td><td> 1 Day 70°F</td><td> 94°F</td><td> 3 Days 70°F 94°F</td><td> 1 Week 70°F 94°F</td><td> 1 Month 70°F 94°F</td>

<td> Solvent</td><td colspan="2"> 1 Week MD CD</td><td colspan="2"> 1 Month 1 Week MD CD MD</td><td> CD</td><td colspan="2"> 1 Month MD CD</td><td> KDA-2076 MD</td><td> 1.4%</td><td> 1.7%</td><td> 1.7% 3.6%</td><td> 3.6%3.6%</td><td rowspan="2"> 4.4% 5.3% 5.0% 6.2% 3.6% 4.4% 5.0% 6.2% 2.7% 3.6% 2.4% 2.4% 5.3% 4.4% 2.4% 3.8 %</td>

<td> Alcaid Oil’ Atreol 34²Klearob, Castor Oil Cod Liver Oil Corn Oil Corvus’ Compression Oil DFO No. 2 Ebony B^sGasoline Glycerine Glycol Kerosene Linseed Oil</td><td rowspan="2"> 1.3% 2.3 2.3 2.3 1.9 4.4 1.3 1.9 3.6 0.0 9.0 0.0 0.0 4.4 3.6 6.3 0.9 1.9 9.0 6.7 2.7 1.3 3.1</td><td colspan="2" rowspan="2"> 1.2% 2.7% 2.6 3.6 2.6 4.0 2.6 3.6 3.8 2.7 3.8 5.4 1.2 2.3 1.8 3.1 3.8 5.4 0.6 0.4 8.8 9.0 0.0 0.0 0.0 0.0 5.0 6.3 3.8 5.4 6.2 8.0 1.2 1.9 1.22.7 7.6 10,1 6.9 10.0 3.2 4.4 1.8 3.1 3.2 4.4</td><td rowspan="2"> 2.6% 0.9% 3.8 1.9 4.4 1.3 3.8 1.9 5.6 3.6 5.0 3.6 2.6 0.9 3.2 1.9 5.6 2.7 1.2 0.4 8.8 8.0 0.0 0.4 0.0 0.0 7.6 5.4 6.2 3.6 8.8 6.3 2.6 0.9 2.6 1.3 6.2 7.8 10.9 7.0 5.0 2.7 3.8 1.3 5.0 3.1</td><td rowspan="2"> .2% 1.8 2.6 2.6 4.4 3.8 0.6 1.8 3.8 0.6 9.4 0.0 0.0 5.6 5.0 6.8 1.2 1.8 5.0 50 3.8 1.8 4.4</td><td colspan="2"> 1.3%.8% 2.3 2.6 2.3 3.2 3.6 3.8 5.4 5.0 5.4 6.2 2.3 2.6 2.7 3.2 4.4 5.0 0.4 0.6 9.0 10.0 0.0 0.0 0.0 0.0 7.1 7.6</td><td> 40 ^CD KDA-2O3O MD CD KDA-2078 MD 45 CD Toywrap MD CD 50 ____________</td><td> 2.0% 1.4% 2.0% 1.4% 2.0% 3.6% 1.2%</td><td> 2.0% 1.7% 2.0% 1.7% 2.0% 2.9% 2.0%</td><td> 1.2%2.4% 1.7%2.7% 2.4%2.4% .86% 1.7% 1.2%2.4% 3.6%3.6% 1.2%2.5%</td><td> 2.4%2.4% 1.7%3.6% 2.4%4.0% 1.7% 1.7% I.2%2.4% 4.4%3.6% 1.2%2.4%</td>

<td> Mineral Spirits Motor Oil No. 10 Motor Oil 10-30 Nitromethane NG (PGD — 90% glycol — 10% (glycerine) Olive Oil Paraffin Oil Peanut Oil</td><td> 7.1 2.7 1.9 7.1 8.8 4.0 1.8 4.4</td><td> 7.6 2.6 2.6 5J) 9.3 5.0 2.6 5.0</td><td colspan="6"> Table 6 shows the percent contraction of 5 by 7” sheets of PVC film after immersion at 70°F. and 104°F. for various periods in “Atreol 34” mineral oil. “Regalite” is the product designation of Tenneco Chemical Co. for a plasticized PVC about 10 mils thick.</td>

TABLKfi

<td></td><td> Di rec- —</td><td colspan="2"> 1 day, percent</td><td> 2 days, iicrcent</td><td colspan="2"> 1 week, percent</td><td colspan="2"> 2 weeks, percent</td><td> 1 month,</td><td> percent</td>

<td> PVC</td><td> tion</td><td> 70° F.</td><td> 104° F.</td><td> 70° F. 104° F.</td><td> 70° F.</td><td> 104° F.</td><td> 70° F.</td><td> 104° F.</td><td> ”0° F.</td><td> 104° F.</td>

<td> Regalite...... KDA 2076 KDA 2030 . .</td><td> MD CD MD CD - . MD CD</td><td> 0 1.2 0.86 1.2 0 1.2</td><td> 2.86 1.2 2.86 1.2 1.9 1.2</td><td> o --</td><td> 0 1.2 1.4 2.0 1.4 1.2</td><td> 4.43 2. 6 5. 29 5.0 3.6 4.0</td><td> 0. 86 1.2 2.86 2.6 1.9 2.6</td><td> 5. 29 4.0 7.1 6.2 5.3 5.0</td><td> 1.86 2.6 3.6 4.0 1.9 4.0</td><td> 6. 29 5.0 8.0 7.4 6.3 6.2</td>

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Virtually any explosive containing about 0.1 to about 80 percent extractor for the plasticizer may be used in this invention. Preferably the explosive should contain about 1 percent to about 10 percent plasticizer-extractor in order to extract the plasticizer in amounts previously described. Dynamite, AN-FO, slurries, and water-in-oil emulsions are four common, suitable explosives which may contain a plasticizer-extractor, usually an oil. Of the four, water-in-oil emulsions are preferred because they exhibit the greatest amount of noticeable product shrinkage and they cause the greatest amount of bag expansion in the polyolefin and copolymer bags commonly used.

A dynamite composition may comprise, for example, 1 pbw (part by weight) inorganic oxidizer salt, about 0.3 to 8 pbw nitroglycerin, nitroglycol, or mixtures thereof, and up to about 0.6 pbw gelatinizing agent such as nitrocotton. Various fuels may also be included.

AN-FO compositions contain ammonium nitrate prills and liquid hydrocarbon fuel, for example, about 78 to 97 percent ammonium nitrate and about 2 to 12 percent liquid hydrocarbon fuel, such as fuel oil which is inexpensive. The compositions may also contain surfactants, metals, additional fuels, sensitizers, and other substances.

An oil-containing slurry explosive may comprise, for example, about 10 to about 70 percent inorganic oxidizer salt, about 10 to about 30 percent water, about 1 to 30 percent oil, and sufficient oil thickener to keep the oil from separating. Other fuels, metals, sensitizers, etc., may also be used.

A water-in-oil emulsion explosive may comprise, for example, about 1 to about 10 percent carbonaceous fuel (e.g., an oil), about 55 to about 87 percent oxidizer, about 0.1 to about 15 percent sensitizer, about 10 to about 25 percent water, about 1/2 to about 2 percent emulsifier, and sufficient gas to give the explosive a density of about 0.9 to about 1.40 gms./cc. (See Bluhm U. S. Pat. No. 3,447,978).

Table 7 shows the shrinkage and effectiveness of AN-FO explosives in PVC bags after various intervals. The PVC bag used was a side lap sealed bag as shown in the accompanying drawing made from “KDA-2076” PVC. Product A is 90 percent whole and ground AN prills, 4 percent No. 2 diesel fuel oil, and 6% al. granules. Product B is 94.25 percent whole Al ground AN prills and 5.75 percent No. 2 diesel fuel oil. The samples were shot with 4” high-velocity gelatin in 5 X 12” cartridges. s

TABLE 7 '

Table 8 gives the density and velocity when shot of various samples of two water-in-oil emulsion explosives prepared according to Bluhm U.S. Pat. No. 3,447,97g after various periods of storage at 90°F. and ambient 5 temperatures. All samples had a density of 1.15 gms./cc. when prepared. Emulsion A contained 2.5 • percent mineral oil. Emulsion B contained 0.5 percent mineral oil. The samples were shot with 3 highvelocity gelatin primer in 3” X 15” cartridges of “K10 DA-2076” PVC.

TABLE 8

<td> Age of</td><td></td><td> Emulsion</td><td colspan="2"> A Emulsion B</td>

<td> Sample</td><td></td><td> Ambient</td><td> 90°F.Ambient</td><td> 90°F.</td>

<td> 15*1 Week</td><td> Velocity (fps)</td><td> 18520</td><td> 1905016670</td><td> 17090</td>

<td></td><td> Density (gms./cc.)</td><td> 1.203</td><td> 1.203 1.207</td><td> 1.203</td>

<td> 3 Months</td><td> Velocity (fps)</td><td> 18520</td><td> 1852016025</td><td> 14425</td>

<td></td><td> Density (gms./cc.)</td><td> 1.223</td><td> 1.197 1.260</td><td> 1.267</td>

<td> 5 Months</td><td> Velocity (fps)</td><td> 18820</td><td> 1852016305</td><td> 10560</td>

<td></td><td> Density (gms./cc.)</td><td> 1.213</td><td> 1.217 1.220</td><td> 1.270</td>

<td> 6 Months</td><td> Velocity (fps)</td><td> 19050</td><td> 19230 14960</td><td> failed</td>

<td> 20</td><td> Density (gms./cc.)</td><td> 1.210</td><td> 1.210 1.257</td><td> 1.287</td>

The above table shows the increase in density of each sample from its original 1.15 gms./cc.