Method of producing biaxially stretched polyester bottles
AssigneeToyo Seikan Kaisha, Ltd.
InventorsKouji Maeda, Kazuhiro Toyama, Takuya Fujikawa
Life of this patent
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Abstract
In effecting the stretching by using a stretch rod in a method of producing a biaxially stretched polyester bottle, the air is blown into the preform at such a flow rate that the preform does not come in contact with the stretch rod but the end thereof and does not come in contact with the surfaces of the mold, either. There can be produced a biaxially stretched polyester bottle having an average thickness of about 0.05 to about 0.2 mm or having a further decreased thickness using a resin in decreased amounts and having a decreased weight without developing burst or whitening caused by over-stretching, without forming ring-like thick portion yet maintaining a good yield and efficiency.
Claims9
A method of producing a biaxially stretched polyester bottle by stretching a polyester preform heated at a stretching temperature by using a stretch rod and by blowing the air, wherein, the temperature for stretching said preform is in a range of 100 to 130° C. on the outer surface of the preform, and a temperature difference between the outer surface of the preform and the inner surface thereof is not larger than 2° C., and in effecting the stretching by using said stretch rod, the air is blown as a pre-blow into the preform at such a flow rate that the preform does not at least come in contact with stretch rod but the end thereof and does not come in contact with the surfaces of the mold, either, the pre-blow air is discontinued simultaneously with the end of the stretching that uses the stretch rod and, thereafter, the stretching is effected by a main blow, said pre-blow for blowing 25 to 40% of the volume of the biaxially stretched bottle blowing the air that has been adjusted to a pressure of 0.05 to 0.1 MPa and a temperature of 200 to 300° C.
Dependencies are inferred from the claim text.