Liquid container and method of manufacturing same

A manufacturing method for a liquid container provided with a bag-shaped container body and a pipe-shaped delivery unit comprising the steps of:

• providing (1) a first pair of flexible films to be formed into flat portions constituting respective front and back walls of the container body, (2) a second pair of flexible films to be formed into a respective pair of gusset portions constituting an associated pair of side walls of the container body and each of said gusset portions having a width approximately equal to that of each flat portion, and (3) a pipe-shaped delivery unit having at least a mouth portion formed at an upper end thereof and a flange portion formed below said mouth portion;
• superposing the first pair of flexible films to be formed into flat portions onto each other;
• folding the second pair of flexible films into a respective pair of gusset portions having associated inward end portions which are projected inwardly of the container body and positioning the respective pair of gusset portions between said superposed two films to be formed into flat portions such that both inward end portions, in which folding lines are formed, face oppositely in a manner of contacting or coming close to each other;
• positioning the delivery unit between said superposed pair of films such that the mouth portion of the delivery unit projects out of an upper end portion of the container body and the flange portion of the delivery unit is held at the upper end portion of the container body so as to subsequently constitute an upper end joining portion between the delivery unit and the container body;
• and
• bonding integrally the respective first and second pairs of films of the flat and gusset portions and the delivery unit by sealing predetermined portions thereof,
• wherein each of the second pair of films for the gusset portions is temporarily bonded to a respective film of the first pair of films of the flat portions before positioning the delivery unit, and
• each inward end portion, at which a folding line is formed, of both films of the two gusset portions is interposed between the flange portion of the delivery unit and the upper end joining portion of the film for the flat portion.