Plastic bottle and method of producing the same

• US 20020088767A1
• Filed: 01/09/2002
• Published: 07/11/2002
• Est. Priority Date: 12/25/1998
• Status: Active Grant

• Current Assignee: TOYO Seikan Kaisha Limited (Toyo Seikan Group Holdings, Ltd.)
• Original Assignee: TOYO Seikan Kaisha Limited (Toyo Seikan Group Holdings, Ltd.)
• Inventors: Saito, Go, Kawaguchi, Kiyoshi, Etoh, Makoto, Maruhashi, Yoshitsugu
• Granted Patent: US 6,716,386 B2
• Time in Patent Office: Days
• US Class Current: 215/40
• CPC Class Codes: B29C 2035/0811 using induction
• CPC Class Codes: B29C 2035/0822 using IR radiation
• CPC Class Codes: B29C 2043/3411 mounted onto arms, e.g. grippers, fingers, clamping frame, suction means
• CPC Class Codes: B29C 2043/3466 using rotating supports, e.g. turntables or drums
• CPC Class Codes: B29C 2043/3689 on a support table, e.g. flat disk-like tables having moulds on the periphery
• CPC Class Codes: B29C 2049/7862 characterised by temperature values or ranges
• CPC Class Codes: B29C 2049/78645 characterised by temperature values or ranges
• CPC Class Codes: B29C 2049/7879 Stretching, e.g. stretch rod
• CPC Class Codes: B29C 2949/0811 Wall thickness
• CPC Class Codes: B29C 2949/0821 of the lip, i.e. the very top of the preform neck
• CPC Class Codes: B29C 2949/0829 Height, length
• CPC Class Codes: B29C 2949/0845 of the body
• CPC Class Codes: B29C 2949/0872 Weight
• CPC Class Codes: B29C 31/048 the material being severed at the dispensing head exit, e.g. as ring, drop or gob, and transported immediately into the mould, e.g. by gravity
• CPC Class Codes: B29C 33/303 centering mould parts or halves, e.g. during mounting
• CPC Class Codes: B29C 43/00 Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor by liberation of internal stresses B29C61/006
• CPC Class Codes: B29C 43/08 with circular movement , e.g. mounted on rolls, turntables
• CPC Class Codes: B29C 43/34 Feeding the material to the mould or the compression means B29C43/085 takes precedence
• CPC Class Codes: B29C 43/50 Removing moulded articles
• CPC Class Codes: B29C 49/02 Combined blow-moulding and manufacture of the preform or the parison
• CPC Class Codes: B29C 49/087 : Means for providing controlled or limited stretch ratio
• CPC Class Codes: B29C 49/12 : Stretching rods
• CPC Class Codes: B29C 49/6605 : Heating the article, e.g. for hot fill
• CPC Class Codes: B29K 2067/00 : Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/253 : Preform
• CPC Class Codes: B65D 1/0223 : characterised by shape

Abstract

A bottle having substantially no strain due to fluidized orientation in the bottom portion thereof which is homogeneously and uniformly drawn, and, as a result, exhibiting improved shock resistance and buckling strength in the bottom portion, featuring excellent resistance against environmental cracking at the center in the bottom portion, without developing crazing or whitening during the preservation, and offering excellent appearance. The bottle is formed by biaxially stretch-blow-molding a thermoplastic resin, and has a mouth portion, a shoulder portion, a barrel portion and a bottom portion, said bottom portion without being substantially affected by the residual strain due to orientation by fluidization.

Claims

1. A bottle formed by biaxially stretch-blow-molding a thermoplastic resin and having a mouth portion, a shoulder portion, a barrel portion and a bottom portion, said bottom portion without being substantially affected by the residual strain due to orientation by fluidization.

2. A bottle according to claim 1, wherein said bottle is formed by biaxially stretch-blow-molding a preform that is formed by compression-molding a thermoplastic resin.

3. A bottle according to claim 2, wherein a difference (tmax−

tmin) between a maximum thickness and a minimum thickness of the barrel portion of said preform in the circumferential direction is not larger than 0.07 mm.

4. A bottle according to claim 1, wherein the bottle is composed of a polyester and the central portion in the bottom portion of the bottle has a diffuse scattering peak in 28 of from 19.45 to 20.50°

as measured by using X-rays (Cu-α

) falling in the direction of thickness of the container wall, a peak position (A) at a portion on the outer surface side of the central portion in the bottom portion is an angle lower than that of a peak position (B) at a portion on the inner surface side of the central portion in the bottom portion, the difference (B−

A) thereof is not smaller than 0.15 degrees, a half-value width (C) of the diffuse scattering peak of X-rays in the portion on the outer surface side at the central portion in the bottom portion is larger than a half-value width (D) of the diffuse scattering peak of X-rays in the portion on the inner surface side at the central portion in the bottom portion, and the difference (C−

D) thereof is not smaller than 0.10 degrees.

5. A bottle according to claim 1, wherein the mouth portion has a support ring, and an annular groove is formed in the inner peripheral edge in the lower surface of the support ring.

6. A method of producing a bottle by biaxially stretch-blow-molding a pre-molded article for blow molding that is obtained through the step of:

extruding a molten thermoplastic resin and cutting it into a mass of melt of nearly a predetermined amount;

arranging a male metal mold and a female metal mold so as to move relative to each other and feeding the mass of melt into the metal mold;

compression-molding the mass of melt into a pre-molded article having a barrel portion with bottom and an annular groove formed in the inner peripheral edge in the lower surface of the support ring; and

cooling and solidifying the compression-molded article and discharging the molded article out of the metal mold.

7. A method of producing a bottle according to claim 6, wherein the mass of melt is compression-molded into the pre-molded article while discharging the air remaining in the metal mold.

8. A method of producing a bottle according to claim 6, wherein fine gaps or holes are formed in a portion of the metal mold forming the bottom portion of the pre-molded article.

9. A method of producing a bottle according to claim 6, wherein the male metal mold is constituted by a core metal mold and a follower metal mold surrounding the core metal mold and is allowed to be opened and closed coaxially therewith, the barrel portion with bottom is molded by the core metal mold and the female metal mold, and the mouth portion is molded by the core metal mold and the follower metal mold.