USH1111H - Mold release technique for solid propellant casting tooling - Google Patents

Mold release technique for solid propellant casting tooling Download PDF

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Publication number
USH1111H
USH1111H US07/678,386 US67838691A USH1111H US H1111 H USH1111 H US H1111H US 67838691 A US67838691 A US 67838691A US H1111 H USH1111 H US H1111H
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United States
Prior art keywords
tooling
mold release
polyvinyl butyral
solid propellant
rods
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US07/678,386
Inventor
William F. Dunn
Larry W. Poulter
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GOVERNMENT OF United States, AIR FORCE THE, Secretary of
US Air Force
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US Air Force
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Priority to US07/678,386 priority Critical patent/USH1111H/en
Assigned to GOVERNMENT OF UNITED STATES OF AMERICA, AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE, THE reassignment GOVERNMENT OF UNITED STATES OF AMERICA, AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE, THE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: THIOKOL CORPORATION, DUNN, WILLIAM F., POULTER, LARRY W.
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Abandoned legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/0033—Moulds or cores; Details thereof or accessories therefor constructed for making articles provided with holes

Definitions

  • This invention relates to tooling which is employed in the casting of solid rocket propellants.
  • a solid propellant rocket generally employs a rocket motor case, insulation, a liner composition, and a solid propellant grain in the order listed as viewed from the outer motor case to the solid propellant grain contained therein.
  • the functions of each of the components of a solid propellant rocket motor are well defined in the art.
  • the solid propellant grain may be processed by extrusion or casting techniques.
  • the majority of modern composite propellants for rocket motors are cast directly into the case as a cross-linkable mixture and cured in place.
  • the thrust-time characteristic of a solid propellant rocket can be controlled by the geometric shape of the grain.
  • Neutral burning grains maintain a constant surface during burning and produce a constant thrust.
  • Progressive burning grains increase in surface during burning and produce an increasing thrust with time.
  • Regressive burning grains decrease in surface during burning and produce a decreasing thrust with time.
  • the geometric shape of a grain is generally understood to be the shape of the internal perforation or perforations.
  • Internally perforated, outwardly burning grains are superior to end burning or external burning grains because the wall area of the motor case is protected from the hot gas generated by combustion.
  • the perforation in a cast solid propellant grain is produced by casting the cross-linkable mixture around shaped casting tooling, curing the mixture and withdrawing the tooling from the cured solid propellant.
  • Glass-filled polytetrafluoroethylene casting tooling is used extensively throughout the solid propellant industry to mold or form the solid propellant grain of rocket motors. From both the safety and design standpoints, it is an ideal material of construction. It is a relatively soft material with a low compressive strength, yet is dimensionally stable. Unfortunately, the mold release properties of this material are reduced as glass filler is added. The mold release properties also degrade with repeated use, because mobile propellant species migrate into the porous glass-filled polymer substrate.
  • improved solid propellant casting tooling consisting essentially of a shaped, filled polymer or copolymer article having at least one outer layer of cured polyvinyl butyral.
  • the improved solid propellant casting tooling of this invention consists essentially of a shaped, filled polymer or copolymer article having an outer layer of cured polyvinyl butyral.
  • this tooling is used extensively throughout the solid propellant industry to mold or form the solid propellant grain of rocket motors.
  • the polymer is commonly a fluorinated alkylene polymer or copolymer, such as polytetrafluoroethylene (PTFE), although other polymeric materials, such as polyethylene, polypropylene, polyvinyl chloride and the like, which are rendered porous by the addition of filler materials, may also be used.
  • the filler may be glass fibers, carbon black, synthetic fibers and the like, including mixtures thereof. The fabrication of such tooling is not a part of the present invention.
  • Polyvinyl butyral resins may be prepared from vinyl acetate according to the following steps: (a) polymerization of vinyl acetate monomer into polyvinyl acetate; (b) partial hydrolysis of polyvinyl acetate to polyvinyl alcohol; (c) reaction of polyvinyl alcohol with n-butyraldehyde to produce polyvinyl butyral/acetate resin.
  • Polyvinyl butyral resins are commercially available from several commercial sources, such as, Monsanto Chemical Co., Union Carbide Co., etc.
  • At least one, preferably at least 3, layers of polyvinyl butyral resin are applied to the outer surface of the casting tooling.
  • the resin can be applied using any conventional technique, such as dipping, spraying, brushing, etc. Sufficient time should be allowed between each layer for the carrier solvent to substantially completely evaporate.
  • the resin coating is cured by heating to about 100° to 140° F. for about 8 to 48 hours. Previously used tooling should be lightly abraded prior to application of the resin.
  • the resin coating and/or the filled polymer or copolymer tooling can be rendered conductive by incorporating therein a conducting ingredient, such as carbon black.
  • the polyvinyl butyral coating lacks mold release properties. Accordingly, prior to using the improved tooling of this invention for casting a propellant grain, a conventional mold release agent is applied to the outer surface.
  • Mold release rods were 1-inch diameter, 5-inch long rods of 25% glass-filled Teflon®.
  • Four coats of polyvinyl butyral (Butvar B-98, Monsanto Chemical Co.) were brushed on the rods with one hour between coats to allow the solvent to evaporate.
  • the thus-coated rods were heated at 120° F for 24 hours to cure the resin coat.
  • a top coat of a conventional fluorocarbon dispersion (Miller-Stephenson Chemical Co., MS-122) was applied to the resin coated rods.
  • the mold release rods were placed in cups and deaerated propellant was placed in the cups around the rods.
  • the propellant was cured and the rods were removed from the cured propellant using an Instron tensile testing machine.
  • the mold release rods were cast into an 88% solids HTPB/Al/AP composite propellant.
  • the propellant was cured for 15 days at 120° F.
  • Table I A summary of the mold release properties is presented in Table I, below:
  • the mold release rods were cast into an 88.1% solids HTPB/AP composite propellant.
  • the propellant was cured for 10 days at 135° F.
  • Table II A summary of the mold release properties is presented in Table II, below:
  • the mold release rods were cast into a 75% solids NEPE/Al/HMX/AP crosslinked double base propellant.
  • the propellant was cured for 5 days at 120° F.
  • Table III A summary of the mold release properties is presented in Table III, below:
  • the mold release rods were coated with 2 or 4 coats of polyvinyl butyral, and 1 or 2 coats of a fluorocarbon mold release agent and cast into an 88% solids HTPB/Al/AP composite propellant.
  • the propellant was cured for 15 days at 120° F.
  • Table IV A summary of the mold release properties is presented in Table IV, below:
  • the mold release rods were coated with two coats of polyvinyl butyral containing 7% carbon. This coating had a measured surface resistivity of 1.0 ⁇ 10 5 ohms.
  • One coat of fluorocarbon mold release agent was applied and the rods were cast into a 88% solids HTPB/Al/AP composite propellant. The propellant was cured for 15 days at 120° F.
  • Table VI A summary of the mold release properties is presented in Table VI, below:

Abstract

Tooling for solid propellant casting consisting essentially of a shaped, filled polymer or copolymer article having an outer layer of cured polyvinyl butyral. The casting tooling is used extensively throughout the solid propellant industry to mold or form the solid propellant grain of rocket motors. The cured polyvinyl butyral layer provides improved mold release properties to the tooling.

Description

RIGHTS OF THE GOVERNMENT
The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.
BACKGROUND OF THE INVENTION
This invention relates to tooling which is employed in the casting of solid rocket propellants.
A solid propellant rocket generally employs a rocket motor case, insulation, a liner composition, and a solid propellant grain in the order listed as viewed from the outer motor case to the solid propellant grain contained therein. The functions of each of the components of a solid propellant rocket motor are well defined in the art.
The solid propellant grain may be processed by extrusion or casting techniques. The majority of modern composite propellants for rocket motors are cast directly into the case as a cross-linkable mixture and cured in place.
The thrust-time characteristic of a solid propellant rocket can be controlled by the geometric shape of the grain. Neutral burning grains maintain a constant surface during burning and produce a constant thrust. Progressive burning grains increase in surface during burning and produce an increasing thrust with time. Regressive burning grains decrease in surface during burning and produce a decreasing thrust with time.
The geometric shape of a grain is generally understood to be the shape of the internal perforation or perforations. Internally perforated, outwardly burning grains are superior to end burning or external burning grains because the wall area of the motor case is protected from the hot gas generated by combustion.
The perforation in a cast solid propellant grain is produced by casting the cross-linkable mixture around shaped casting tooling, curing the mixture and withdrawing the tooling from the cured solid propellant. Glass-filled polytetrafluoroethylene casting tooling is used extensively throughout the solid propellant industry to mold or form the solid propellant grain of rocket motors. From both the safety and design standpoints, it is an ideal material of construction. It is a relatively soft material with a low compressive strength, yet is dimensionally stable. Unfortunately, the mold release properties of this material are reduced as glass filler is added. The mold release properties also degrade with repeated use, because mobile propellant species migrate into the porous glass-filled polymer substrate. Conventional mold release agents are ineffective with this tooling since they are not impervious and allow species migration into the glass-filled polymer substrate. Conventional cleaning methods are also ineffective since they do not remove subsurface contamination. Thus, repeated usage of glass-filled polytetrafluoroethylene casting tooling results in removal difficulties and damage to the propellant grain in the form of surface tears.
Accordingly, it is an object of this invention to provide a method for modifying solid propellant casting tooling to provide improved mold release.
It is another object of this invention to provide improved solid propellant casting tooling.
Other objects, aspects and advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the invention.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided improved solid propellant casting tooling consisting essentially of a shaped, filled polymer or copolymer article having at least one outer layer of cured polyvinyl butyral.
There is also provided a method for modifying solid propellant casting tooling consisting essentially of a shaped, filled polymer or copolymer article to provide improved mold release, which consists essentially of applying at least one outer coating of polyvinyl butyral to the shaped article and curing the same.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The improved solid propellant casting tooling of this invention consists essentially of a shaped, filled polymer or copolymer article having an outer layer of cured polyvinyl butyral. As mentioned previously, this tooling is used extensively throughout the solid propellant industry to mold or form the solid propellant grain of rocket motors. The polymer is commonly a fluorinated alkylene polymer or copolymer, such as polytetrafluoroethylene (PTFE), although other polymeric materials, such as polyethylene, polypropylene, polyvinyl chloride and the like, which are rendered porous by the addition of filler materials, may also be used. The filler may be glass fibers, carbon black, synthetic fibers and the like, including mixtures thereof. The fabrication of such tooling is not a part of the present invention.
Polyvinyl butyral resins may be prepared from vinyl acetate according to the following steps: (a) polymerization of vinyl acetate monomer into polyvinyl acetate; (b) partial hydrolysis of polyvinyl acetate to polyvinyl alcohol; (c) reaction of polyvinyl alcohol with n-butyraldehyde to produce polyvinyl butyral/acetate resin. Polyvinyl butyral resins are commercially available from several commercial sources, such as, Monsanto Chemical Co., Union Carbide Co., etc. Three such resins available under the tradename Butvar (Monsanto Chemical Co.) have the compositions (designation/vinyl alcohol content (wt %)/vinyl acetate content (wt%)/vinyl butyral content (wt %)/approximate molecular wt): B-72A/19/1.0/80/3500; B-76/11/1.0/88/750; B-98/19/1.0/80/500.
At least one, preferably at least 3, layers of polyvinyl butyral resin are applied to the outer surface of the casting tooling. The resin can be applied using any conventional technique, such as dipping, spraying, brushing, etc. Sufficient time should be allowed between each layer for the carrier solvent to substantially completely evaporate. The resin coating is cured by heating to about 100° to 140° F. for about 8 to 48 hours. Previously used tooling should be lightly abraded prior to application of the resin.
For use with electrostatic-sensitive propellants, the resin coating and/or the filled polymer or copolymer tooling can be rendered conductive by incorporating therein a conducting ingredient, such as carbon black.
The polyvinyl butyral coating lacks mold release properties. Accordingly, prior to using the improved tooling of this invention for casting a propellant grain, a conventional mold release agent is applied to the outer surface.
The following Examples illustrate the invention. Mold release rods were 1-inch diameter, 5-inch long rods of 25% glass-filled Teflon®. Four coats of polyvinyl butyral (Butvar B-98, Monsanto Chemical Co.) were brushed on the rods with one hour between coats to allow the solvent to evaporate. The thus-coated rods were heated at 120° F for 24 hours to cure the resin coat. A top coat of a conventional fluorocarbon dispersion (Miller-Stephenson Chemical Co., MS-122) was applied to the resin coated rods.
In the tests which follow, glass-filled Teflon rods, without the polyvinyl butyral coating, and with and without the fluorocarbon dispersion coating, were used for comparison.
The mold release rods were placed in cups and deaerated propellant was placed in the cups around the rods. The propellant was cured and the rods were removed from the cured propellant using an Instron tensile testing machine.
EXAMPLE I
The mold release rods were cast into an 88% solids HTPB/Al/AP composite propellant. The propellant was cured for 15 days at 120° F. A summary of the mold release properties is presented in Table I, below:
              TABLE I                                                     
______________________________________                                    
               Shear Stress (psi)                                         
Set    Coating(s)    n*       Mean  Std. Dev.                             
______________________________________                                    
1      None          4        32.8  1.3                                   
2      1 fluorocarbon                                                     
                     4        36.5  2.9                                   
3      4 polyvinyl butyral                                                
                     12       23.5  0.9                                   
       1 fluorocarbon                                                     
______________________________________                                    
 *number of samples in set.
Examination of the above data reveals that the uncoated glass-filled Teflon rods in Set 1 released with an average shear stress of 32.8 psi. The addition of one coat of fluorocarbon release agent (set 2) was ineffective, with an average release shear stress of 36.5 psi. In contrast, the rods coated with 4 coats of polyvinyl butyral and one coat of fluorocarbon release agent (set 3) had an average shear stress of 23.5 psi, an improvement of about 28% in mold release properties over the uncoated glass-filled Teflon rods.
EXAMPLE II
The mold release rods were cast into an 88.1% solids HTPB/AP composite propellant. The propellant was cured for 10 days at 135° F. A summary of the mold release properties is presented in Table II, below:
              TABLE II                                                    
______________________________________                                    
               Shear Stress (psi)                                         
Set    Coating(s)    n        Mean  Std. Dev.                             
______________________________________                                    
4      None          4        25.8  1.5                                   
5      1 fluorocarbon                                                     
                     4        26.9  1.1                                   
6      4 polyvinyl butyral                                                
                     12       18.5  1.9                                   
       1 fluorocarbon                                                     
______________________________________
Examination of the above data reveals that the rods coated with 4 coats of polyvinyl butyral and one coat of fluorocarbon release agent (set 6) had an average shear stress of 18.5 psi, an improvement of about 28% in mold release properties over the uncoated glass-filled Teflon rods (set 4).
EXAMPLE III
The mold release rods were cast into a 75% solids NEPE/Al/HMX/AP crosslinked double base propellant. The propellant was cured for 5 days at 120° F. A summary of the mold release properties is presented in Table III, below:
              TABLE III                                                   
______________________________________                                    
               Shear Stress (psi)                                         
Set    Coating(s)    n        Mean  Std. Dev.                             
______________________________________                                    
7      None          4        46.5  4.8                                   
8      1 fluorocarbon                                                     
                     4        34.0  2.0                                   
9      4 polyvinyl butyral                                                
                     12       23.2  1.9                                   
       1 fluorocarbon                                                     
______________________________________
Examination of the above data reveals that the rods coated with 4 coats of polyvinyl butyral and one coat of fluorocarbon release agent (set 9) had an average shear stress of 23.2 psi, an improvement of about 50% in mold release properties over the uncoated glass-filled Teflon rods (set 7).
EXAMPLE IV
The mold release rods were coated with 2 or 4 coats of polyvinyl butyral, and 1 or 2 coats of a fluorocarbon mold release agent and cast into an 88% solids HTPB/Al/AP composite propellant. The propellant was cured for 15 days at 120° F. A summary of the mold release properties is presented in Table IV, below:
              TABLE IV                                                    
______________________________________                                    
               Shear Stress (psi)                                         
Set    Coating(s)    n        Mean  Std. Dev.                             
______________________________________                                    
10     None          3        38.2  2.7                                   
11     1 fluorocarbon                                                     
                     3        34.7  2.4                                   
12     2 fluorocarbon                                                     
                     3        30.4  2.6                                   
13     2 polyvinyl butyral                                                
                     9        26.1  0.8                                   
       1 fluorocarbon                                                     
14     2 polyvinyl butyral                                                
                     3        23.5  0.3                                   
       2 fluorocarbon                                                     
15     4 polyvinyl butyral                                                
                     3        24.2  0.9                                   
       1 fluorocarbon                                                     
16     4 polyvinyl butyral                                                
                     9        23.3  0.8                                   
       2 fluorocarbon                                                     
______________________________________
Examination of the above data reveals that the rods coated with 1 or 2 coats of fluorocarbon release agent (sets 11 and 12, respectively) reduced mold release requirements by about 10 and 20%, respectively, over the uncoated glass-filled Teflon rods (set 10). The addition of 2 coats of polyvinyl butyral and one coat of fluorocarbon release agent (set 13) provided an improvement of about 30% as compared to the uncoated rods (set 10). The addition of 2 coats of polyvinyl butyral and 2 coats of fluorocarbon release agent (set 14) or 4 coats of polyvinyl butyral and 1 or 2 coats of fluorocarbon release agent (sets 15 and 16, respectively), reduced the mold release requirements by about 40%.
EXAMPLE V
The polyvinyl butyral-coated rods from examples I, II and III (sets 3, 6 and 9) were cleaned of residual propellant using methyl chloroform. The polyvinyl butyral was undisturbed with this cleaning. The fluorocarbon mold release agent was freshly applied. The refurbished rods were cast into the same propellants, cured and the rods removed. A summary of the mold release properties is presented in Table V, below:
              TABLE V                                                     
______________________________________                                    
                Shear Stress (psi)                                        
Set   Propellant      1st use  2nd use                                    
                                      3d use                              
______________________________________                                    
3A    HTPB/Al/AP      23.5     25.9   26.3                                
6A    HTPB/AP         18.5     20.0   16.1                                
9A    NEPE/Al/HMX/AP  23.2     22.4   17.8                                
______________________________________
Examination of the above data reveals that the refurbished rods retain their improved mold release properties through 3 complete cycles.
EXAMPLE VI
The mold release rods were coated with two coats of polyvinyl butyral containing 7% carbon. This coating had a measured surface resistivity of 1.0 ×105 ohms. One coat of fluorocarbon mold release agent was applied and the rods were cast into a 88% solids HTPB/Al/AP composite propellant. The propellant was cured for 15 days at 120° F. A summary of the mold release properties is presented in Table VI, below:
              TABLE VI                                                    
______________________________________                                    
                Shear Stress (psi)                                        
Set   Coating(s)      n       Mean   Std. Dev.                            
______________________________________                                    
17    None            3       38.2   2.7                                  
18    2 polyvinyl butyral**                                               
                      3       21.9   5.3                                  
      1 fluorocarbon                                                      
______________________________________                                    
 **with 7% carbon.
Examination of the above data reveals that the rods coated with 2 coats of polyvinyl butyral with 7% carbon and one coat of fluorocarbon release agent (set 18) had an average shear stress of 21.9 psi, an improvement of about 43% in mold release properties over the uncoated glass-filled Teflon rods.
Various modifications may be made to the invention as described without departing from the spirit of the invention or the scope of the appended claims.

Claims (5)

We claim:
1. Tooling for solid propellant casting consisting essentially of a shaped, filled polymer or copolymer article having at least one outer layer of cured polyvinyl butyral.
2. The tooling of claim 1 wherein said shaped, filled article is polytetrafluoroethylene.
3. The tooling of claim 2 wherein said shaped, filled article contains about 25% glass filler.
4. The tooling of claim 2 wherein said polyvinyl butyral layer contains carbon black.
5. The tooling of claim 4 wherein said polyvinyl butyral layer contains about 7% carbon black.
US07/678,386 1991-04-01 1991-04-01 Mold release technique for solid propellant casting tooling Abandoned USH1111H (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020190426A1 (en) * 2001-02-09 2002-12-19 Seidner Nathan M. Static dissipative mold release agent and use in casting and molding processes
US6783615B1 (en) * 2002-01-29 2004-08-31 The United States Of America As Represented By The Secretary Of The Army Insensitive explosives for high speed loading applications
CN116120137A (en) * 2022-12-27 2023-05-16 上海航天化工应用研究所 Composite solid propellant based on core-shell aluminum powder and preparation method thereof

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3466204A (en) 1965-07-23 1969-09-09 Ici Ltd Process for the preparation of an explosive composition coated with polytetrafluoroethylene
US3761047A (en) 1971-08-09 1973-09-25 Gould Inc Mold coating
US3870578A (en) 1962-07-24 1975-03-11 Us Army Polyurethane propellant
US4004523A (en) 1965-10-27 1977-01-25 Clifford David V Solid propellant charges
US4009231A (en) 1975-03-20 1977-02-22 The United States Of America As Represented By The Secretary Of The Navy Powder barrier bonding technique
US4084781A (en) 1976-08-05 1978-04-18 The United States Of America As Represented By The Secretary Of The Navy Fabrication of ablator liners in combustors
US4099376A (en) 1955-06-29 1978-07-11 The B.F. Goodrich Company Gas generator and solid propellant with a silicon-oxygen compound as a burning rate modifier, and method for making the same
US4197800A (en) 1970-09-04 1980-04-15 Hercules Incorporated Single chamber rap having centerport inhibitor
US4284592A (en) 1975-04-09 1981-08-18 Imperial Metal Industries (Kynoch) Limited Combustion inhibitors
US4429634A (en) 1977-01-06 1984-02-07 Thiokol Corporation Adhesive liner for case bonded solid propellant
US4601862A (en) 1984-02-10 1986-07-22 Morton Thiokol, Inc. Delayed quick cure rocket motor liner
US4744299A (en) 1983-04-01 1988-05-17 The United States Of America As Represented By The Secretary Of The Army Impermeable liner-barrier for propellants containing a high content of carborane burning rate accelerator
US4803019A (en) 1984-02-10 1989-02-07 Morton Thiokol, Inc. Process for forming a liner and cast propellant charge in a rocket motor casing

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099376A (en) 1955-06-29 1978-07-11 The B.F. Goodrich Company Gas generator and solid propellant with a silicon-oxygen compound as a burning rate modifier, and method for making the same
US3870578A (en) 1962-07-24 1975-03-11 Us Army Polyurethane propellant
US3466204A (en) 1965-07-23 1969-09-09 Ici Ltd Process for the preparation of an explosive composition coated with polytetrafluoroethylene
US4004523A (en) 1965-10-27 1977-01-25 Clifford David V Solid propellant charges
US4197800A (en) 1970-09-04 1980-04-15 Hercules Incorporated Single chamber rap having centerport inhibitor
US3761047A (en) 1971-08-09 1973-09-25 Gould Inc Mold coating
US4009231A (en) 1975-03-20 1977-02-22 The United States Of America As Represented By The Secretary Of The Navy Powder barrier bonding technique
US4284592A (en) 1975-04-09 1981-08-18 Imperial Metal Industries (Kynoch) Limited Combustion inhibitors
US4084781A (en) 1976-08-05 1978-04-18 The United States Of America As Represented By The Secretary Of The Navy Fabrication of ablator liners in combustors
US4429634A (en) 1977-01-06 1984-02-07 Thiokol Corporation Adhesive liner for case bonded solid propellant
US4744299A (en) 1983-04-01 1988-05-17 The United States Of America As Represented By The Secretary Of The Army Impermeable liner-barrier for propellants containing a high content of carborane burning rate accelerator
US4601862A (en) 1984-02-10 1986-07-22 Morton Thiokol, Inc. Delayed quick cure rocket motor liner
US4803019A (en) 1984-02-10 1989-02-07 Morton Thiokol, Inc. Process for forming a liner and cast propellant charge in a rocket motor casing

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020190426A1 (en) * 2001-02-09 2002-12-19 Seidner Nathan M. Static dissipative mold release agent and use in casting and molding processes
US6783615B1 (en) * 2002-01-29 2004-08-31 The United States Of America As Represented By The Secretary Of The Army Insensitive explosives for high speed loading applications
CN116120137A (en) * 2022-12-27 2023-05-16 上海航天化工应用研究所 Composite solid propellant based on core-shell aluminum powder and preparation method thereof

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