Mold and stretch-blow molded polyester bottle
A mold for producing a stretch-blow molded polyester bottle from a preform comprises mold parts that can be shifted between an open position and a closed position. The mold comprises: first and second mold shell, within which, in the closed position, a bottle body can be molded; a holding stopper, which can be inserted into a bottle neck; a blow pin having a compressed-air intake for biaxial stretching of the preform; and a bottom part, which closes the two mold shells at the bottom side and is configured to mold the bottle bottom. A base is formed on the bottom part, which base projects into an interior of the mold and has a side wall with an inclination angle (α) of at most 5 degrees with respect to a vertical axis ( 35 ) of the mold and is oriented in parallel with the vertical axis.
1 . A mold for producing a stretch-blow-molded polyester bottle having a bottle neck, a bottle body, and a bottle bottom from a preform, comprising a first mold shell and a second mold shell configured to mold the bottle body when the first and second mold shells are in a closed position,
a holding stopper configured to be inserted into the bottle neck,
a blow pin having a compressed-air intake for biaxial stretching of the preform,
a bottom part that closes the two mold shells on the bottom side and is configured to mold the bottle bottom, and
a base formed on the bottom part that includes only a single projection that projects into an interior of the mold, the base having a side wall oriented in parallel with the vertical axis of the mold,
wherein the base projects beyond the remaining bottom part at a height between 5 and 7 mm.
2 . The mold according to claim 1 , wherein a negative form for an outer part of a standing surface of the bottle bottom is formed at lower ends of the first and second mold shells.
3 . The mold according to claim 2 , wherein a negative mold for an inner part of the standing surface of the bottle bottom is formed on the base following the side wall.
4 . A stretch-blow-molded polyester bottle comprising:
a bottle neck,
a bottle body adjoining the bottle neck,
a bottle bottom having an outer standing surface and only a single inner indentation delimited by the standing surface,
the bottle produced with a mold, comprising:
a first mold shell and a second mold shell configured to mold the bottle body when the first and second mold shells are in a closed position,
a holding stopper configured to be inserted into the bottle neck,
a blow pin having a compressed-air intake for biaxial stretching of a preform,
a bottom part that closes the two mold shells on the bottom side and is configured to mold the bottle bottom, and
a base formed on the bottom part that includes only a single projection that projects into an interior of the mold, the base having a side wall oriented in parallel with the vertical axis of the mold,
wherein the base projects beyond the remaining bottom part at a height between 5 and 7 mm.
5 . The polyester bottle according to claim 4 , wherein the inner indentation has a side wall which has a side wall angle (β) relative to the outer standing surface between 60 and 80 degrees.
6 . The polyester bottle according to claim 5 , wherein polyester material of the inner indentation is forcibly stretched by the side wall angle (β) in a direction of an interior of the bottle.
7 . The polyester bottle according to claim 6 , wherein restoring forces of the polyester material of the inner indentation are reduced by the side wall angle (β).
8 . The polyester bottle according to claim 4 , wherein the bottle is produced in the mold with a cycle time between 10% to 20% shorter than a cycle time required for an identical bottle but with a conventionally molded bottom.
9 . The polyester bottle according to claim 4 , wherein the inner indentation has a side wall which has a side wall angle (β) relative to the outer standing surface between 65 and 70 degrees.