초록 ▼

Apparatus for producing a container from a tubular blank of polyethylene terephthalate or similar material, according to which a polyethylene terephthalate blank is stretched at least approximately 3-fold to produce a preform (20). In an axial section through the preform, the contour length substant

Apparatus for producing a container from a tubular blank of polyethylene terephthalate or similar material, according to which a polyethylene terephthalate blank is stretched at least approximately 3-fold to produce a preform (20). In an axial section through the preform, the contour length substantially corresponds to the contour length in an axial section through the final container. The preform (20) is heated to a temperature above the glass transition temperature (TG) and is converted to the container (21) in a blow mold (12). In doing so, the contour length of the material is maintained through successive reduction of the axial length of the body (23) which the preform constitutes during the conversion to the container. In order to achieve this, the base portion of the blow mold (11) is moved towards the orifice (22) of the final container. The container acquires a neck portion (23) and a container body (26) which are axially oriented, in the case of polyethylene terephthalate to an extent corresponding to about a 3-fold monoaxial stretching, while the container body (26) is also transversely oriented, in the case of polyethylene terephthalate to an extent corresponding to about a 3-fold stretching as a maximum. The wall thickness of the container is inversely proportional to the radius of the container.

대표청구항 ▼

Apparatus for forming a container from orientable thermoplastic material comprising: a mold having a molding cavity, means for holding a hollow preform of thermoplastic material in said molding cavity of said mold, said preform having one end held by the holding means and including a side wall and a

Apparatus for forming a container from orientable thermoplastic material comprising: a mold having a molding cavity, means for holding a hollow preform of thermoplastic material in said molding cavity of said mold, said preform having one end held by the holding means and including a side wall and a closed end opposite said one end, the material of said side wall having axial orientation and being capable of circumferential expansion and circumferential orientation, said mold including a mold body and a movable mold part in said mold body having a surface facing said closed end of the preform, said movable mold part being movable in said mold body between a retracted position and an advanced position, means for expanding the preform in the mold cavity to form the container without any axial stretching of said side wall, the relative position of said holding means and said movable mold part in its retracted position being such that said preform, prior to its formation to the finished shape of said container, comes into contact with said movable mold part, means for displacing said movable mold part between the retracted and advanced positions while said preform is held by said holding means and is in contact with the movable mold part; and means for controlling the displacing of said movable mold part from said retracted to said advanced position while the preform is being expanded to coordinate the displacement of the movable mold part with the expanding of the preform such that the material of the side wall is not stretched in a plane perpendicular to the direction of expanding and thereby the material does not undergo any axial strain due to elongation and said expanding produces circumferential stretching and circumferential orientation of the material in said side wall independent of and superimposed on said axial orientation, said means for expanding the preform comprising a blow mandrel projecting within said cavity to support said preform and secured in stationary relation in said mold, said blow mandrel projecting a substantial distance in said cavity and having an end spaced from the movable part in its retracted position so that the preform extends from the holding means onto said mandrel and beyond said end of the mandrel towards said movable mold part in its retracted position prior to said expanding of the preform, said end of the mandrel being substantially adjacent to the movable mold part in the advanced position thereof.