Manufacturing method of synthetic resin hollow body

Abstract

A manufacturing method of a synthetic resin hollow body in which a molten resin is injected for an over-molding outside a hollow molding body made of a resin provided with a hollow body and at least an opening portion to form a resin sheathing body in an integrating manner with the hollow molding body. The method includes the step of injecting the molten resin for an over-molding under the state in which the hollow molding body is partially or wholly filled with a fluid substance. The manufacturing method of a synthetic resin hollow body is capable of suppressing resin cost and operation cost and can improve decorating property.

1 . A manufacturing method of a synthetic resin hollow body (A) in which a molten resin is injected for an over-molding outside a hollow molding body (a) which is made of a resin, is hollow inside and is provided with at least an opening portion to form a resin sheathing body in an integrating manner with the hollow molding body (a), which method comprising the steps of:
 filling partially the hollow molding body (a) with a liquid as a fluid substance, the rest of the hollow molding body (a) filled with air, or filling wholly the hollow molding body (a) with a liquid as a fluid substance,   attaching a cap member to the opening portion,   setting the hollow molding body (a) holding the liquid inside to a metal mold, and   injecting the molten resin into the metal mold for an over-molding wherein the liquid is one of water, an aqueous solution, a cosmetic solution, a chemical, and an organic solvent,   whereby the resin sheathing body is formed to cover the entire of the hollow molding body (a) from the bottom end of the opening portion.   
     
     
         2 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein the resin sheathing body is welded to an external surface of the hollow molding body (a). 
     
     
         3 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein a boiling point of the liquid is at least 50° C. 
     
     
         4 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein the molding temperature is in the range of 100° C. to 300° C. and the injection pressure is in the range of 20 to 150 kg/cm 2  in the case in which the molten resin is injected into the metal mold. 
     
     
         5 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein the molten resin to be injected into the metal mold is an ionomer resin. 
     
     
         6 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein the hollow molding body (a) is formed by a blow molding method or a method of welding two divided molding bodies using a vibration welding method. 
     
     
         7 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein the hollow molding body (a) is a thin-walled molding body. 
     
     
         8 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein a thickness of the resin sheathing body is at least 1 mm. 
     
     
         9 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , wherein the hollow molding body (a) is a hollow molding container. 
     
     
         10 . The manufacturing method of a synthetic resin hollow body (A) as defined in  claim 1 , which method further comprises the step of removing the liquid from the hollow molding body (a) after the molten resin is hardened.