Method for producing a container for a bulk product

Abstract

The invention relates to a container ( 10 ) for a bulk product, comprising a housing ( 12 ) and a rubber-elastic force-generating body ( 24 ) protruding into the housing and having a filling space for receiving the bulk product. The force-generating body has a closed first longitudinal end and is suspended relative to the housing in the area of an opposite second longitudinal end. When being filled, the force-generating body expands radially and axially in the housing in such a manner that, when a partially filled state is reached, said body makes contact with a first wall part ( 16 ) of the housing ( 12 ) radially bounding the expansion, and when filling is continued, the first longitudinal end approaches a second wall part ( 18 ) of the housing axially bounding the expansion as the axial enlargement of the area of contact between the force-generating body and the first wall part increases. Before the force-generating body is filled, at least one part of the first wall part on the inside of the housing and/or at least one part of the outer face of the force-generating body is subjected to a friction-reducing surface treatment.

1 . A method for manufacturing a container for a filling product, the method comprising:
 forming a container having a housing and a rubber-like force generating body projecting into the housing and having a longitudinal axis and a filling space for receiving the filling product, wherein the force-generating body has a closed first longitudinal end and is suspended relative to the housing in the region of an opposite second longitudinal end, wherein the force-generating body, when being filled, expands radially and axially with respect to the longitudinal axis in the housing in such a manner that it abuts on a first wall portion of the housing upon reaching a partial filling state, the first wall portion limiting the expansion radially, and that upon continued filling the first longitudinal end approaches a second wall portion of the housing while the area of abutment of the force-generating body on the first wall portion progressively axially increases, the second wall portion delimiting the expansion axially;   subjecting, prior to filling the force-generating body, at least a part of the first wall portion on a housing inner-side to a friction-reducing surface treatment; and   subjecting, prior to filling the force generating body, at least a part of the force-generating body an outside thereof to a friction-reducing surface treatment.   
     
     
         2 . The method of  claim 1 , wherein the surface treatment includes applying a friction-reducing substance to at least one of the first wall portion and the force-generating body. 
     
     
         3 . The method of  claim 2 , wherein the friction-reducing substance is applied through one of a spraying, immersion, centrifuging and brush process. 
     
     
         4 . The method of  claim 2 , wherein the friction-reducing substance is a water-based lubricant. 
     
     
         5 . The method of  claim 2 , wherein the friction-reducing substance is a lubricant that is free of silicone-based or mineral oil-based components. 
     
     
         6 . The method of  claim 2 , wherein the friction-reducing substance is a non-adhesive lubricant. 
     
     
         7 . The method of  claim 1 , wherein the surface treatment includes a fluorination of at least one of the first wall portion and the force-generating body. 
     
     
         8 . The method of  claim 1 , wherein the housing is made of one of polyethylene and polypropylene. 
     
     
         9 . The method of  claim 1 , wherein the housing is made of one of polymethyl methacrylate and polyethylene terephthalate and the surface treatment brings about a permanent friction-reducing coating on at least one of the first wall portion and the force-generating body. 
     
     
         10 . The method of  claim 1 , wherein the force-generating body is made of a silicone rubber. 
     
     
         11 . The method of  claim 1 , wherein the first wall portion has at least one recess at a housing inner-side wall surface in the area of abutment of the force-generating body. 
     
     
         12 . A container manufactured by a method as defined in  claim 1 . 
     
     
         13 . A container for a filling product, the container comprising:
 a housing; and   a rubber-like force-generating body projecting into the housing and having a longitudinal axis and a filling space for receiving the filling product, wherein the force-generating body has a closed first longitudinal end and is suspended relative to the housing in the region of an opposite second longitudinal end,   wherein the force-generating body, when being filled, expands radially and axially with respect to the longitudinal axis in the housing in such a manner that it abuts on a first wall portion of the housing upon reaching a partial filling state, the first wall portion limiting the expansion radially, and that upon continued filling the first longitudinal end approaches a second wall portion of the housing while the area of abutment of the force-generating body on the first wall portion progressively axially increases, the second wall portion delimiting the expansion axially,   wherein during the expansion of the force-generating body at least portions of the force-generating body perform a sliding movement on the first wall portion,   wherein the first wall portion has one or more recesses at a housing inner-side wall surface in the area of abutment of the force-generating body.   
     
     
         14 . The method of  claim 1 , wherein the force-generating body, upon reaching the partial filling state, abuts on the first wall portion of the housing at a distance from the second longitudinal end. 
     
     
         15 . The method of  claim 11 , wherein the recess is shaped as a groove.