Method of blow-molding biaxially oriented polyethylene terephthalate resin bottle-shaped container

A method for blow-molding a biaxially oriented polyethylene terephthalate resin bottle-shaped container having high heat resistance, comprising the steps of:

• providing a preform with a neck and a body;
• heating the preform to an orienting temperature;
• first biaxial-orientation blow-molding the preform in a first mold which is at a first temperature to biaxially stretch the preform to form a primary intermediate molded bottle-shaped piece that is larger than the bottle-shaped container and having an area magnification of at least 5 times the preform, the biaxial stretching creating residual stress in the primary intermediate molded bottle-shaped piece;
• causing thermal contraction of the primary intermediate molded bottle-shaped piece by heating said primary intermediate molded bottle-shaped piece to a temperature higher than the first temperature to form a secondary intermediate molded bottle-shaped piece and to eliminate residual stress caused by the first blow-molding;
• and
• second blow-molding the secondary intermediate molded bottle-shaped piece in a second mold to form the bottle-shaped container, wherein orientation magnification of the secondary intermediate molded bottle-shaped piece is small compared to orientation magnification of the primary intermediate molded bottle-shaped piece.

A method for blow-molding a biaxially oriented polyethylene terephthalate resin bottle-shaped container having high heat resistance, comprising the steps of:

• providing a preform with a neck and a body;
• heating the preform to an orienting temperature;
• first biaxial-orientation blow-molding the preform in a first mold which is at a first temperature to biaxially stretch the preform to form a primary intermediate molded bottle-shaped piece that is larger than the bottle-shaped container, the biaxial stretching creating residual stress in the primary intermediate molded bottle-shaped piece;
• causing thermal contraction of the primary intermediate molded bottle-shaped piece by heating said primary intermediate molded bottle-shaped piece to a second temperature, wherein said second temperature is higher than the first temperature and is in the range of 200.degree. to 255.degree. C. to form a secondary intermediate molded bottle-shaped piece and to eliminate residual stress caused by the first blow-molding;
• and
• second blow-molding the secondary intermediate molded bottle-shaped piece in a second mold to form the bottle-shaped container, wherein orientation magnification of the secondary intermediate molded bottle-shaped piece is small compared to orientation magnification of the primary intermediate molded bottle-shaped piece.

A method for blow-molding a biaxially oriented polyethylene terephthalate resin bottle-shaped container, comprising the steps of:

• a) forming a preform having a preliminary shape including a neck and a body;
• b) first biaxial-orientation blow-molding the preform in a first mold to form a primary intermediate molded bottle-shaped piece, wherein the primary intermediate molded bottle-shaped piece has an area magnification from the preform in the range of 5-13 times and a density of 1.36 gm/cc or more, by the steps of
• (i) heating the body of the preform to a temperature that approaches but does not reach a thermal crystallization temperature of polyethylene terephthalate resin, and
• (ii) blow-molding the preform in a blow-mold heated to a temperature in the range of 110.degree. C. to 230.degree. C. to form a primary intermediate molded bottle-shaped piece that is larger than the bottle-shaped container;
• c) causing thermal contraction of the primary intermediate molded bottle-shaped piece to form a secondary intermediate molded bottle-shaped piece to eliminate residual stress in the primary intermediate molded bottle-shaped piece from the first blow, wherein the secondary intermediate molded bottle-shaped piece is formed by the step of
• heating the primary intermediate molded bottle-shaped piece to a temperature of at least 20.degree. C. greater than the temperature of the mold of said step of first biaxial orientation blow-molding;
• and
• d) second blow-molding the secondary intermediate molded bottle-shaped piece in a second mold to form the bottle-shaped container, wherein orientation magnification of the secondary intermediate molded bottle-shaped piece is small compared to orientation magnification of the primary intermediate molded bottle-shaped piece and substantially no stress is created when the bottle-shaped container is blow-molded, by the steps of
• (i) placing the secondary intermediate molded bottle-shaped piece in a mold heated to a temperature in the range of 100.degree. C. to 150.degree. C., and
• (ii) blow-molding the molded secondary intermediate molded bottle-shaped piece into the bottle-shaped container.

A method of blow-molding a biaxially-oriented polyethylene terephthalate resin bottle-shaped container comprising:

• heating a preform at a temperature that approaches but does not reach the thermal crystallization temperature of the polyethylene terephthalate resin;
• biaxial-orientation blow molding the preform in a primary blow mold which is at a primary blow mold temperature to biaxially stretch the preform to form a primary intermediate molded bottle-shaped piece that is larger than the bottle-shaped container;
• and
• forming the bottle-shaped container from the primary intermediate molded bottle-shaped piece;
• wherein the primary intermediate molded bottle-shaped piece is heated to a temperature higher than the primary blow mold temperature to thermally shrink and eliminate residual stress from the primary intermediate bottle-shaped piece to form a secondary intermediate molded bottle-shaped piece;
• and
• further wherein the secondary intermediate molded bottle-shaped piece is blow molded in a secondary blow mold to form the bottle-shaped container and orientation magnification of the secondary intermediate molded bottle-shaped piece is small compared to orientation magnification of the primary intermediate molded bottle-shaped piece.