Molding method and mold therefor

Abstract

A cap filled with fluid sealant is produced for subsequent attachment to an exposed portion of a fastener, such as a bolt head. The cap has a shell made of a synthetic resin formed in a generally hemispherical, hollow shape, and a recess defined by an inner surface of the shell in a generally hemispherical shape. The method includes filling the recess with a fluid sealant, which contains a mixture of a thermosetting substance and a curing agent that is freezable prior to curing, such that while the sealant is frozen, no curing takes place, and when the sealant is subsequently heated and thawed, its original fluidity is restored and curing of the thermosetting substance restarts. The sealant is then frozen while the sealant is filled in the cap. Subsequently the sealant is thawed and any condensation that forms on the sealant or the cap during the thawing is removed by drying.

1 .- 20 . (canceled) 
     
     
         21 . A method for producing a cap to be attached to an exposed portion of a fastener, with which a fastened member is fastened, wherein the exposed portion of the fastener, before the cap is attached thereto, projects from a surface of the fastened member, and after the cap has attached to the exposed portion, the cap encloses the exposed portion of the fastener,
 wherein the cap has: a shell made of synthetic resin formed in a generally hemispherical, hollow shape, and a recess defined by an inner surface of the shell in a generally hemispherical shape,   the method comprising:   prior to attachment of the cap to the exposed portion of the fastener, filling the recess with a sealant, wherein the sealant is fluid before being completely cured and exhibits: (a) thermosetting properties in which the sealant cures when heated, and once cured, original properties of the sealant are not restored even if the temperature of the sealant decreases, and (b) properties in which, when the sealant is cooled prior to curing, the sealant is frozen, and when the sealant is subsequently heated and thawed, its original fluidity is restored and curing of the sealant restarts;   freezing the sealant by freezing the cap filled with the sealant; and   thawing the cap filled with the sealant and drying the cap to remove any condensation that forms on the cap during the thawing.   
     
     
         22 . The method according to  claim 21 , further comprising degassing the sealant before filling the recess with the sealant. 
     
     
         23 . The method according to  claim 21 , further comprising degassing the sealant while the sealant is disposed in the recess. 
     
     
         24 . The method according to  claim 21 , wherein the thawing/drying step is performed such that the thawing of the sealant and the drying of the cap are concurrently executed by blowing room-temperature air or hot air onto the cap filled with the frozen sealant. 
     
     
         25 . The method according to  claim 21 , wherein the thawing/drying step includes thawing the sealant by heating the cap filled with the frozen sealant using a heater or by immersing the cap filled with the frozen sealant in hot water. 
     
     
         26 . The method according to  claim 21 , wherein the sealant is made of the same synthetic resin as the cap. 
     
     
         27 . The method according to  claim 23 , wherein the sealant is degassed by:
 placing the cap filled with the sealant in a container holder of a mixer, and   then orbiting the container holder about a first rotational axis while rotating the container holder about a second rotational axis that is inclined relative to the first rotational axis.   
     
     
         28 . The method according to  claim 27 , wherein the container holder is placed under a partial vacuum while the degassing step is being performed. 
     
     
         29 . The method according to  claim 28 , wherein the sealant is frozen at a temperature of about −50° C. and about −70° C. 
     
     
         30 . The method according to  claim 21 , wherein the sealant is frozen at a temperature of about −50° C. and about −70° C. 
     
     
         31 . A method for making a cap filled with a fluid sealant, wherein the cap has a generally hemispherical outer shell made of a solid synthetic resin and a generally hemispherical recess defined by an inner surface of the outer shell,
 the method comprising:   disposing the fluid sealant in the recess, the fluid sealant comprising a mixture of a thermosetting substance and a curing agent that is freezable prior to curing, such that while the mixture is frozen, no curing takes place, and when the mixture is subsequently heated and thawed, its original fluidity is restored and irreversible curing of the thermosetting substance proceeds;   freezing the sealant while the fluid sealant is disposed in the cap; and   subsequently thawing the sealant and drying the sealant and cap to remove any condensation that forms thereon during the thawing.   
     
     
         32 . The method according to  claim 31 , further comprising degassing the fluid sealant before the fluid sealant is disposed in the recess. 
     
     
         33 . The method according to  claim 31 , further comprising degassing the fluid sealant while the fluid sealant is disposed in the recess and prior to the freezing step. 
     
     
         34 . The method according to  claim 31 , wherein the thawing/drying step is performed such that the thawing and the drying are concurrently executed by blowing room-temperature or hotter air onto the cap filled with the frozen sealant. 
     
     
         35 . The method according to  claim 31 , wherein the thawing/drying step includes thawing the sealant by heating the cap filled with the frozen sealant using a heater or by immersing the cap filled with the frozen sealant in hot water. 
     
     
         36 . The method according to  claim 31 , wherein the sealant is made of the same synthetic resin as the cap. 
     
     
         37 . The method according to  claim 33 , wherein the fluid sealant is degassed by:
 placing the cap containing the fluid sealant in a container holder of a mixer, and   then orbiting the container holder about a first rotational axis while rotating the container holder about a second rotational axis that is inclined relative to the first rotational axis.   
     
     
         38 . The method according to  claim 37 , wherein the container holder is placed under a partial vacuum while the degassing step is being performed. 
     
     
         39 . The method according to  claim 38 , wherein the sealant is frozen at a temperature of about −50° C. and about −70° C. 
     
     
         40 . The method according to  claim 31 , wherein the sealant is frozen at a temperature of about −50° C. and about −70° C.