US3107573A - Method of restricting a solid propellant - Google Patents
Method of restricting a solid propellant Download PDFInfo
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- US3107573A US3107573A US65855A US6585560A US3107573A US 3107573 A US3107573 A US 3107573A US 65855 A US65855 A US 65855A US 6585560 A US6585560 A US 6585560A US 3107573 A US3107573 A US 3107573A
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- Prior art keywords
- fabric
- cellulose acetate
- solvent
- solid propellant
- grain
- Prior art date
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- Expired - Lifetime
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- 238000000034 method Methods 0.000 title claims description 18
- 239000004449 solid propellant Substances 0.000 title claims description 16
- 239000004744 fabric Substances 0.000 claims description 39
- 229920002301 cellulose acetate Polymers 0.000 claims description 23
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000000576 coating method Methods 0.000 description 17
- 239000000463 material Substances 0.000 description 17
- 239000011248 coating agent Substances 0.000 description 14
- 239000002904 solvent Substances 0.000 description 14
- 239000000835 fiber Substances 0.000 description 12
- 239000004014 plasticizer Substances 0.000 description 11
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- URAYPUMNDPQOKB-UHFFFAOYSA-N triacetin Chemical compound CC(=O)OCC(OC(C)=O)COC(C)=O URAYPUMNDPQOKB-UHFFFAOYSA-N 0.000 description 8
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 7
- 239000003380 propellant Substances 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 6
- DOOTYTYQINUNNV-UHFFFAOYSA-N Triethyl citrate Chemical compound CCOC(=O)CC(O)(C(=O)OCC)CC(=O)OCC DOOTYTYQINUNNV-UHFFFAOYSA-N 0.000 description 5
- 235000019504 cigarettes Nutrition 0.000 description 5
- 239000001069 triethyl citrate Substances 0.000 description 5
- VMYFZRTXGLUXMZ-UHFFFAOYSA-N triethyl citrate Natural products CCOC(=O)C(O)(C(=O)OCC)C(=O)OCC VMYFZRTXGLUXMZ-UHFFFAOYSA-N 0.000 description 5
- 235000013769 triethyl citrate Nutrition 0.000 description 5
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 4
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 235000019441 ethanol Nutrition 0.000 description 4
- 239000001087 glyceryl triacetate Substances 0.000 description 4
- 235000013773 glyceryl triacetate Nutrition 0.000 description 4
- 239000007800 oxidant agent Substances 0.000 description 4
- 229960002622 triacetin Drugs 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 230000001419 dependent effect Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000009736 wetting Methods 0.000 description 3
- XLLIQLLCWZCATF-UHFFFAOYSA-N 2-methoxyethyl acetate Chemical compound COCCOC(C)=O XLLIQLLCWZCATF-UHFFFAOYSA-N 0.000 description 2
- GDDNTTHUKVNJRA-UHFFFAOYSA-N 3-bromo-3,3-difluoroprop-1-ene Chemical compound FC(F)(Br)C=C GDDNTTHUKVNJRA-UHFFFAOYSA-N 0.000 description 2
- 239000010425 asbestos Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- SWXVUIWOUIDPGS-UHFFFAOYSA-N diacetone alcohol Chemical compound CC(=O)CC(C)(C)O SWXVUIWOUIDPGS-UHFFFAOYSA-N 0.000 description 2
- LZCLXQDLBQLTDK-UHFFFAOYSA-N ethyl 2-hydroxypropanoate Chemical compound CCOC(=O)C(C)O LZCLXQDLBQLTDK-UHFFFAOYSA-N 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 229910052895 riebeckite Inorganic materials 0.000 description 2
- WEAPVABOECTMGR-UHFFFAOYSA-N triethyl 2-acetyloxypropane-1,2,3-tricarboxylate Chemical compound CCOC(=O)CC(C(=O)OCC)(OC(C)=O)CC(=O)OCC WEAPVABOECTMGR-UHFFFAOYSA-N 0.000 description 2
- 239000002759 woven fabric Substances 0.000 description 2
- WSLDOOZREJYCGB-UHFFFAOYSA-N 1,2-Dichloroethane Chemical compound ClCCCl WSLDOOZREJYCGB-UHFFFAOYSA-N 0.000 description 1
- IZRWZLBCZMYWIG-UHFFFAOYSA-N 1,2-dinitro-3-phenylbenzene Chemical group [O-][N+](=O)C1=CC=CC(C=2C=CC=CC=2)=C1[N+]([O-])=O IZRWZLBCZMYWIG-UHFFFAOYSA-N 0.000 description 1
- CBSCOKJVHQZELD-UHFFFAOYSA-N 1-[1-(2,3-dinitrophenoxy)ethoxy]-2,3-dinitrobenzene Chemical compound [N+](=O)([O-])C=1C(=C(OC(C)OC2=C(C(=CC=C2)[N+](=O)[O-])[N+](=O)[O-])C=CC1)[N+](=O)[O-] CBSCOKJVHQZELD-UHFFFAOYSA-N 0.000 description 1
- DMYOHQBLOZMDLP-UHFFFAOYSA-N 1-[2-(2-hydroxy-3-piperidin-1-ylpropoxy)phenyl]-3-phenylpropan-1-one Chemical compound C1CCCCN1CC(O)COC1=CC=CC=C1C(=O)CCC1=CC=CC=C1 DMYOHQBLOZMDLP-UHFFFAOYSA-N 0.000 description 1
- JSZOAYXJRCEYSX-UHFFFAOYSA-N 1-nitropropane Chemical compound CCC[N+]([O-])=O JSZOAYXJRCEYSX-UHFFFAOYSA-N 0.000 description 1
- DYSXLQBUUOPLBB-UHFFFAOYSA-N 2,3-dinitrotoluene Chemical compound CC1=CC=CC([N+]([O-])=O)=C1[N+]([O-])=O DYSXLQBUUOPLBB-UHFFFAOYSA-N 0.000 description 1
- VOZKAJLKRJDJLL-UHFFFAOYSA-N 2,4-diaminotoluene Chemical compound CC1=CC=C(N)C=C1N VOZKAJLKRJDJLL-UHFFFAOYSA-N 0.000 description 1
- XNWFRZJHXBZDAG-UHFFFAOYSA-N 2-METHOXYETHANOL Chemical compound COCCO XNWFRZJHXBZDAG-UHFFFAOYSA-N 0.000 description 1
- SVONRAPFKPVNKG-UHFFFAOYSA-N 2-ethoxyethyl acetate Chemical compound CCOCCOC(C)=O SVONRAPFKPVNKG-UHFFFAOYSA-N 0.000 description 1
- BMTAFVWTTFSTOG-UHFFFAOYSA-N Butylate Chemical compound CCSC(=O)N(CC(C)C)CC(C)C BMTAFVWTTFSTOG-UHFFFAOYSA-N 0.000 description 1
- 229920002284 Cellulose triacetate Polymers 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 229920001079 Thiokol (polymer) Polymers 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- YIWOOPQOYHKISC-UHFFFAOYSA-N [O-][N+](=O)CC(O)([N+]([O-])=O)OC1=CC=CC=C1 Chemical compound [O-][N+](=O)CC(O)([N+]([O-])=O)OC1=CC=CC=C1 YIWOOPQOYHKISC-UHFFFAOYSA-N 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 229940116333 ethyl lactate Drugs 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- SUHBNXXIQCNCAG-UHFFFAOYSA-N methanol;1-nitropropane Chemical compound OC.CCC[N+]([O-])=O SUHBNXXIQCNCAG-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 description 1
- VLZLOWPYUQHHCG-UHFFFAOYSA-N nitromethylbenzene Chemical compound [O-][N+](=O)CC1=CC=CC=C1 VLZLOWPYUQHHCG-UHFFFAOYSA-N 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
- C06B21/0083—Treatment of solid structures, e.g. for coating or impregnating with a modifier
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
- C06B45/12—Compositions or products which are defined by structure or arrangement of component of product having contiguous layers or zones
Definitions
- Solid propellants for use in rocket motors or gas generators must burn in a controlled manner. This control is obtained by forcing the combustion to be limited to selected portion(s) of the surface of the solid propellant grain. For example, a rod-like grain which is desired to burn in cigarette fashion must be prevented from burning on the cylindrical surface thereof. Regardless of how tightly the grain may be fitted into a rocket motor or a gas generator combustion chamber, hot gases tend to leak between the wall and the surface of the grain and cause combustion where it is not wanted.
- Solid propellant grains are forced to burn in a desired manner by applying to selected portion(s) of the surface a flame restriction coating commonly called a restrictor.
- the restrictor is a material which is either relatively inert or burns so much more slowly than'the propellant material itself that the propellant beneath the restrictor does not burn until the flame reaches it.
- cellulose acetate sheet For example, in a rod that is desired to burn cigarette fashion a sheet of cellulose acetate is glued to the cylindrical surface. This procedure sounds simple but the job of adhering the sheet to the surface has been found to be difiicult and frequently unsatisfactory. Also, where there are irregular surfaces to be restricted, it is diflicult to shape and adhere cellulose acetate sheet to these irregular surfaces. On the other hand, cellulose acetate is relatively incombustible and reasonably cheap and can be softened by many solvents and plasticizers so that it is a very suitable restricting material when cellulose heet can be applied to the surface of the grain.
- fiber as used herein means a thread like material capable of being spun, woven, knitted, or felted.
- the restrictor coating may be formed from cellulose acetate fibers which are in the form of woven fabric, knit fabric, felt fabric, or formed into non-woven cloth wherein a binder holds the fibers in place. All types of woven and knit fabrics which are available from the textile industry are suitable for use in the invention.
- the cellulose acetate fiber may be derived from any cellulose acetate which can be formed into thread like structures. By the use of special solvents, fibers can be formed from material which is essentially cellulose triacetate. In general, the cellulose acetate fibers will be formed from material having a combined acetic acid value of 53-60%
- the solid propellant grain consists essentially of a body formed from the particular solid propellant and adhered celulose fiber restrictor coating.
- the solid propellant body may be made up of any of the materials used for this purpose. These propellants may be double base powder, ammonium nitrate, ammonium perchlorate, etc.
- the ammonium nitrate and ammonium perchlorate propellants comprise the oxidizer and a combustible organic atent "too material binder therefor.
- These binders may be thermoplastic materials which are a mixture of organic polymer and a plasticizer therefor.
- cellulose acetate, cellulose acetate butylate, polyvinyl chloride, polyvinyl acetate are suitable polymers with ammonium nitrate oxidizer.
- suitable plasticizers are known for these materials, such as triethyl citrate, dinitro diphenyl oxide, dinitro toluene, and triacetin. Rubber-like materials, such as Thiokol rubber, GRS rubber, and the like may be used as binders.
- the coating of cellulose acetate fiber must be adhered to the surface to be restricted. This is preferably done by solvent-softening the fabric.
- the softening may be accomplished by a material which is capable of dissolving the particular cellulose acetate or merely softening the fibers and causing stickiness; or a plasticizer type solvent may be used to accomplish the softening of the cellulose acetate fibers. It is desirable to use as the solvent-softener a material which will also soften appreciably the surface of the solid propellant body to which the fabric is to be adhered.
- solventsofteners are: methyl acetate, acetone, methyl ethyl ketone, commercial ethyl acetate, 99% ethyl acetate, methyl Cellosolve acetate, methyl Cellosolve, Cellosolve acetate, nitrornethane ethyl alcohol, nitromethane, nitropropane ethyl alcohol, nitropropane methanol, ethyl lactate, diacetone alcohol, methylene chloride ethyl alcohol, ethylene dichloride ethyl alcohol.
- suitable plasticizers are triethyl citrate, acetyl triethyl citrate, triacetin, nitrotoluene, etc.
- solvent-softener used will be dependent upon the particular material, the amount of restrictor coating needed, and the type of configuration to be restricted.
- sufiicient solvent-softener is used to adhere the fabric to the surface to permit fit of the fabric to surface irregularities during the enplacing operation.
- the fabric may be applied to the surface by wetting the fabric with the plasticizer or solvent and then applying the wet fabric to the surface.
- the fabric may be wrapped around the surface for the particular number of layers needed to provide the desired amount of restriction.
- the fabric may be positioned on the surface and then wet with the plasticizer or solvent. When end burning rods are desired, it is preferred to wet the fabric prior to positioning as this avoids wrinkles when several layers of fabric are needed for the particular coating.
- the solvent may be permitted to evaporate at ordinary temperatures or at somewhat elevated temperatures, dependent upon the boiling point of the solvent and the facilities available.
- solvent softeners which are more in the nature of plasticizer
- the finished grain is obtained by heating the body and wet fabric affixed thereto at a temperature suitable for setting the fabric.
- temperatures on the order of ISO-250 F. may be used.
- Sufiicient time is permitted at the particular temperature for the removal of the solvent for setting of the plasticizer. The particular time will be dependent upon the temperature, the solvent, or the plasticizer and the thickness of the restrictor coating.
- the dried grain has a tough, resilient covering at the portion where the cellulose acetate fabric has been adhered.
- the coating performs as well as cellulose acetate sheets applied by the more usual methods. It has been noted that thicker coatings are permissible with the cellulose acetate fabric method of applying the restrictor coating. It has also been observed that the presence of the bubbles beneath the fabric restrictor or between layers of fabric does not impair the flame-restriction quality of the coating as it does so frequently in cellulose acetatesheet restrictors. V
- the cellulose acetate fabric restrictor has been utilized with ammonium nitrate propellants in all the manners in which other restrictors have been applied.
- other restrictors For example, as coatings on rods to provide cigarette burning; as annular discs aifixed to the end of tubular grains which provide burning on the cylindrical surfaces inward toward and outward from the center of the grain; also as annular discs applied to the ends of tubes and as cylindrical surface coatings providing burning from the inside toward the outer surface of the grain.
- the restricted grain be positioned in the rocket motor or generator combustion chamber so that the restrictor surface is close fitting against the wall of the motor or chamber. Where insulation is desired to protect the'metal of the chamber, appropriate insulators may be applied to the restricted surface or the grain may be inserted into an asbestos tube for use as a cigarette burning grain.
- ammonium nitrate oxidizer 62%
- binder made up of cellulose acetate (54-56% combined acetic acid), 12%
- acetyl triethyl citrate 9%
- dinitrophenoxyethanol 6%
- bis(dinitrophenoxy)ethane 3%
- the propellant contained carbon black, 4%
- toluene diamine 1%
- catalyst 3%.
- Cigarette burning grains ranging in diameter from one inch to five inches were prepared by applying commercially purchased acetate rayon cloth to the outside cylindrical surface. Inside-outside burnings were prepared by restricting the annular end surface of a five inch diameter hole.
- test grains were prepared by the plasticizer method with a triethyl citrate or triacetin to soak the cloth before applying the cloth to the surface to be restricted. In multi-layer applications, the wet cloth was then covered with a damp cloth to seal off the wet cloth. For convenience, the burners were inserted into an asbestos sleeve to support the grain during the time that the grain was maintained at 170 F. for about 12 hours to set the restrictor coating. Other grains were prepared by wrapping dry cloth about the grain and then wetting with acetone or methyl acetate. The wet grains were permitted to remain exposed at room temperature of 1.
- a method of restricting a solid propellant body which method consists essentially of (a) applying a solvent-softened fabric formed from cellulose acetate fiber to a selected portion of the surface of a solid propellant body, in the thickness desired to accomplish flame-restriction, and (b) heating said coated body to a temperature and for a time needed to adhere said fabric to said surface.
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- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Chemistry (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Description
United States 3,107,573 METHGD {1F RESTRICTENG A SOLID PROPELLANT This invention relates to solid propellants provided with a flame restriction coating on a portion of the surface thereof.
Solid propellants for use in rocket motors or gas generators must burn in a controlled manner. This control is obtained by forcing the combustion to be limited to selected portion(s) of the surface of the solid propellant grain. For example, a rod-like grain which is desired to burn in cigarette fashion must be prevented from burning on the cylindrical surface thereof. Regardless of how tightly the grain may be fitted into a rocket motor or a gas generator combustion chamber, hot gases tend to leak between the wall and the surface of the grain and cause combustion where it is not wanted. Solid propellant grains are forced to burn in a desired manner by applying to selected portion(s) of the surface a flame restriction coating commonly called a restrictor. The restrictor is a material which is either relatively inert or burns so much more slowly than'the propellant material itself that the propellant beneath the restrictor does not burn until the flame reaches it.
Many materials have been used as restrictors. One of the earliest materials and one still widely used is cellulose acetate sheet. For example, in a rod that is desired to burn cigarette fashion a sheet of cellulose acetate is glued to the cylindrical surface. This procedure sounds simple but the job of adhering the sheet to the surface has been found to be difiicult and frequently unsatisfactory. Also, where there are irregular surfaces to be restricted, it is diflicult to shape and adhere cellulose acetate sheet to these irregular surfaces. On the other hand, cellulose acetate is relatively incombustible and reasonably cheap and can be softened by many solvents and plasticizers so that it is a very suitable restricting material when cellulose heet can be applied to the surface of the grain.
It has been discovered that all types of solid propellants can be very successfully restricted with cellulose acetate restrictor coating when the coating is formed from cellulose acetate fibers adhered to the surface of the solid propellant body which is desired to be restricted.
The term fiber as used herein means a thread like material capable of being spun, woven, knitted, or felted. The restrictor coating may be formed from cellulose acetate fibers which are in the form of woven fabric, knit fabric, felt fabric, or formed into non-woven cloth wherein a binder holds the fibers in place. All types of woven and knit fabrics which are available from the textile industry are suitable for use in the invention.
The cellulose acetate fiber may be derived from any cellulose acetate which can be formed into thread like structures. By the use of special solvents, fibers can be formed from material which is essentially cellulose triacetate. In general, the cellulose acetate fibers will be formed from material having a combined acetic acid value of 53-60% The solid propellant grain consists essentially of a body formed from the particular solid propellant and adhered celulose fiber restrictor coating. The solid propellant body may be made up of any of the materials used for this purpose. These propellants may be double base powder, ammonium nitrate, ammonium perchlorate, etc. The ammonium nitrate and ammonium perchlorate propellants comprise the oxidizer and a combustible organic atent "too material binder therefor. These binders may be thermoplastic materials which are a mixture of organic polymer and a plasticizer therefor. For example, cellulose acetate, cellulose acetate butylate, polyvinyl chloride, polyvinyl acetate, are suitable polymers with ammonium nitrate oxidizer. Numerous suitable plasticizers are known for these materials, such as triethyl citrate, dinitro diphenyl oxide, dinitro toluene, and triacetin. Rubber-like materials, such as Thiokol rubber, GRS rubber, and the like may be used as binders.
The coating of cellulose acetate fiber must be adhered to the surface to be restricted. This is preferably done by solvent-softening the fabric. The softening may be accomplished by a material which is capable of dissolving the particular cellulose acetate or merely softening the fibers and causing stickiness; or a plasticizer type solvent may be used to accomplish the softening of the cellulose acetate fibers. It is desirable to use as the solvent-softener a material which will also soften appreciably the surface of the solid propellant body to which the fabric is to be adhered. Examples of suitable solventsofteners are: methyl acetate, acetone, methyl ethyl ketone, commercial ethyl acetate, 99% ethyl acetate, methyl Cellosolve acetate, methyl Cellosolve, Cellosolve acetate, nitrornethane ethyl alcohol, nitromethane, nitropropane ethyl alcohol, nitropropane methanol, ethyl lactate, diacetone alcohol, methylene chloride ethyl alcohol, ethylene dichloride ethyl alcohol. Illustrative of suitable plasticizers are triethyl citrate, acetyl triethyl citrate, triacetin, nitrotoluene, etc.
The amount of solvent-softener used will be dependent upon the particular material, the amount of restrictor coating needed, and the type of configuration to be restricted. In general, sufiicient solvent-softener is used to adhere the fabric to the surface to permit fit of the fabric to surface irregularities during the enplacing operation.
The fabric may be applied to the surface by wetting the fabric with the plasticizer or solvent and then applying the wet fabric to the surface. In the case of a rod or similar material whose cylindrical surface is to be restricted, the fabric may be wrapped around the surface for the particular number of layers needed to provide the desired amount of restriction. Instead of wetting the fabric prior to applying it to the surface, the fabric may be positioned on the surface and then wet with the plasticizer or solvent. When end burning rods are desired, it is preferred to wet the fabric prior to positioning as this avoids wrinkles when several layers of fabric are needed for the particular coating. When a low-boiling solvent, such as acetone or methyl acetate is used, the solvent may be permitted to evaporate at ordinary temperatures or at somewhat elevated temperatures, dependent upon the boiling point of the solvent and the facilities available. In the case of solvent softeners which are more in the nature of plasticizer, the finished grain is obtained by heating the body and wet fabric affixed thereto at a temperature suitable for setting the fabric. When a material such as triethyl citrate or triacetin is the solventsoftener, temperatures on the order of ISO-250 F. may be used. Sufiicient time is permitted at the particular temperature for the removal of the solvent for setting of the plasticizer. The particular time will be dependent upon the temperature, the solvent, or the plasticizer and the thickness of the restrictor coating.
The dried grain has a tough, resilient covering at the portion where the cellulose acetate fabric has been adhered. The coating performs as well as cellulose acetate sheets applied by the more usual methods. It has been noted that thicker coatings are permissible with the cellulose acetate fabric method of applying the restrictor coating. It has also been observed that the presence of the bubbles beneath the fabric restrictor or between layers of fabric does not impair the flame-restriction quality of the coating as it does so frequently in cellulose acetatesheet restrictors. V
The cellulose acetate fabric restrictor has been utilized with ammonium nitrate propellants in all the manners in which other restrictors have been applied. For example, as coatings on rods to provide cigarette burning; as annular discs aifixed to the end of tubular grains which provide burning on the cylindrical surfaces inward toward and outward from the center of the grain; also as annular discs applied to the ends of tubes and as cylindrical surface coatings providing burning from the inside toward the outer surface of the grain. It is preferred that the restricted grain be positioned in the rocket motor or generator combustion chamber so that the restrictor surface is close fitting against the wall of the motor or chamber. Where insulation is desired to protect the'metal of the chamber, appropriate insulators may be applied to the restricted surface or the grain may be inserted into an asbestos tube for use as a cigarette burning grain.
An illustrative ammonium nitrate propellant which has been restricted with the cellulose acetate fabric by the method of the invention is: ammonium nitrate oxidizer, 62%; binder made up of cellulose acetate (54-56% combined acetic acid), 12%; acetyl triethyl citrate, 9%; dinitrophenoxyethanol, 6%; and bis(dinitrophenoxy)ethane, 3%; in addition the propellant contained carbon black, 4%; toluene diamine, 1%; and catalyst, 3%. Cigarette burning grains ranging in diameter from one inch to five inches were prepared by applying commercially purchased acetate rayon cloth to the outside cylindrical surface. Inside-outside burnings were prepared by restricting the annular end surface of a five inch diameter hole.
These test grains were prepared by the plasticizer method with a triethyl citrate or triacetin to soak the cloth before applying the cloth to the surface to be restricted. In multi-layer applications, the wet cloth was then covered with a damp cloth to seal off the wet cloth. For convenience, the burners were inserted into an asbestos sleeve to support the grain during the time that the grain was maintained at 170 F. for about 12 hours to set the restrictor coating. Other grains were prepared by wrapping dry cloth about the grain and then wetting with acetone or methyl acetate. The wet grains were permitted to remain exposed at room temperature of 1. A method of restricting a solid propellant body which method consists essentially of (a) applying a solvent-softened fabric formed from cellulose acetate fiber to a selected portion of the surface of a solid propellant body, in the thickness desired to accomplish flame-restriction, and (b) heating said coated body to a temperature and for a time needed to adhere said fabric to said surface. 7
2. The. method of claim 1 wherein said solvent is acetone.
3. The method of claim 1 wherein said solvent is methyl acetate.
4.'The method of claim 1 wherein said solvent is triethyl citrate.
5. The method of claim 4 wherein said temperature is about 250 F. e
6. The method of claim 1 wherein said fabric is a woven fabric.
7. The method of claim 1 wherein said fabric is a knit fabric.
8. The method of claim 1 wherein said fabric is a felt fabric.
9. The method of claim 1 wherein said body comprises ammonium nitrate oxidizer and a combustible organic material binder therefor.
References Cited in the file of this patent UNITED STATES PATENTS Campbell et al Nov. 1, 1960
Claims (1)
1. A METHOD OF RESTRICTING A SOLID PROPELLANT BODY WHICH METHOD CONSISTS ESSENTIALLY OF (A) APPLYING A SOLVENT-SOFTENED FABRIC FORMED FROM CELLULOSE ACETATE FIBER TO A SELECTED PORTION OF THE SURFACE OF A SOLID PROPELLANT BODY, IN THE THICKNESS DESIRED TO ACCOMPLISH FLAME-RESTRICTION, AND (B) HEATING SAID COATED BY TO A TEMPERATURE AND FOR A TIME NEEDED TO ADHERE SAID FABRIC TO SAID SURFACE.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US65855A US3107573A (en) | 1960-10-28 | 1960-10-28 | Method of restricting a solid propellant |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US65855A US3107573A (en) | 1960-10-28 | 1960-10-28 | Method of restricting a solid propellant |
Publications (1)
Publication Number | Publication Date |
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US3107573A true US3107573A (en) | 1963-10-22 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US65855A Expired - Lifetime US3107573A (en) | 1960-10-28 | 1960-10-28 | Method of restricting a solid propellant |
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Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3263613A (en) * | 1964-05-28 | 1966-08-02 | Atlantic Res Corp | Elastic sheet |
US3278356A (en) * | 1963-05-31 | 1966-10-11 | Katz Daniel | Method for fastening perforated propellant sticks to a suspension plate |
US3311013A (en) * | 1963-01-09 | 1967-03-28 | Aerojet General Co | Propellant liner |
US3338990A (en) * | 1964-05-28 | 1967-08-29 | Atlantic Res Corp | Method of making an inhibited, gas-producing charge |
US3381065A (en) * | 1966-05-27 | 1968-04-30 | Standard Oil Co | Method for restricting propellant grains |
US3493446A (en) * | 1968-09-17 | 1970-02-03 | Us Navy | Method for applying a burn inhibitor material to a composite propellant grain |
US4766814A (en) * | 1963-12-26 | 1988-08-30 | Wilson Lloyd C | Materials for thermal protection by rapid smoke production |
DE102016121081A1 (en) | 2015-11-05 | 2017-05-11 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Ausstosstriebwerk as annular combustion chamber with device for stabilizing a fuel assembly to form outflow channels |
DE102015120196A1 (en) | 2015-11-20 | 2017-05-24 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Propellant reinforcement with fabric insert, fuel reinforcement |
DE102017100058A1 (en) | 2016-02-22 | 2017-08-24 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Device for stabilizing a fuel assembly with formation of outflow channels |
US20210290818A1 (en) * | 2016-03-24 | 2021-09-23 | Locate Therapeutics Limited | Scaffolding material, methods and uses |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2539404A (en) * | 1945-05-28 | 1951-01-30 | Aerojet Engineering Corp | Solid propellant charge for rocket motors |
US2858289A (en) * | 1953-05-25 | 1958-10-28 | Hercules Powder Co Ltd | Combustion inhibitor for gas-producing charges |
US2958288A (en) * | 1960-11-01 | campbell |
-
1960
- 1960-10-28 US US65855A patent/US3107573A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2958288A (en) * | 1960-11-01 | campbell | ||
US2539404A (en) * | 1945-05-28 | 1951-01-30 | Aerojet Engineering Corp | Solid propellant charge for rocket motors |
US2858289A (en) * | 1953-05-25 | 1958-10-28 | Hercules Powder Co Ltd | Combustion inhibitor for gas-producing charges |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3311013A (en) * | 1963-01-09 | 1967-03-28 | Aerojet General Co | Propellant liner |
US3278356A (en) * | 1963-05-31 | 1966-10-11 | Katz Daniel | Method for fastening perforated propellant sticks to a suspension plate |
US4766814A (en) * | 1963-12-26 | 1988-08-30 | Wilson Lloyd C | Materials for thermal protection by rapid smoke production |
US3338990A (en) * | 1964-05-28 | 1967-08-29 | Atlantic Res Corp | Method of making an inhibited, gas-producing charge |
US3263613A (en) * | 1964-05-28 | 1966-08-02 | Atlantic Res Corp | Elastic sheet |
US3381065A (en) * | 1966-05-27 | 1968-04-30 | Standard Oil Co | Method for restricting propellant grains |
US3493446A (en) * | 1968-09-17 | 1970-02-03 | Us Navy | Method for applying a burn inhibitor material to a composite propellant grain |
DE102016121081A1 (en) | 2015-11-05 | 2017-05-11 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Ausstosstriebwerk as annular combustion chamber with device for stabilizing a fuel assembly to form outflow channels |
DE102016121081B4 (en) | 2015-11-05 | 2022-06-15 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Ejection engine as an annular combustion chamber with a device for stabilizing a propellant arrangement with the formation of outflow channels |
DE102015120196A1 (en) | 2015-11-20 | 2017-05-24 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Propellant reinforcement with fabric insert, fuel reinforcement |
DE102017100058A1 (en) | 2016-02-22 | 2017-08-24 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Device for stabilizing a fuel assembly with formation of outflow channels |
DE102017100058B4 (en) | 2016-02-22 | 2024-06-20 | Bayern-Chemie Gesellschaft Für Flugchemische Antriebe Mbh | Device for stabilizing a fuel arrangement by forming outflow channels |
US20210290818A1 (en) * | 2016-03-24 | 2021-09-23 | Locate Therapeutics Limited | Scaffolding material, methods and uses |
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