U.S. patent application number 14/963807 was filed with the patent office on 2016-04-07 for preform neck crystallization method.
This patent application is currently assigned to NISSEI ASB MACHINE CO. LTD.. The applicant listed for this patent is NISSEI ASB MACHINE CO. LTD.. Invention is credited to YOICHI TSUCHIYA.
Application Number | 20160096309 14/963807 |
Document ID | / |
Family ID | 45003869 |
Filed Date | 2016-04-07 |
United States Patent
Application |
20160096309 |
Kind Code |
A1 |
TSUCHIYA; YOICHI |
April 7, 2016 |
PREFORM NECK CRYSTALLIZATION METHOD
Abstract
A neck crystallization method includes inserting a core into the
neck, heating the neck using a heater group disposed along a
transfer direction while rotating the preform on its axis, and
transferring the preform along the transfer direction in a state in
which the core is inserted into the neck, and cooling the neck of
the preform in a state in which the core is inserted into the neck.
The heating of the neck includes a first step that drives first
heaters positioned on the upstream side in the transfer direction
at a first power, and a second step that drives second heaters
positioned on the downstream side of the first heaters at a second
power that is lower than the first power until the temperature of
the neck reaches a crystallization temperature zone.
Inventors: |
TSUCHIYA; YOICHI; (NAGANO,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NISSEI ASB MACHINE CO. LTD. |
NAGANO |
|
JP |
|
|
Assignee: |
NISSEI ASB MACHINE CO. LTD.
NAGANO
JP
|
Family ID: |
45003869 |
Appl. No.: |
14/963807 |
Filed: |
December 9, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13685472 |
Nov 26, 2012 |
9238341 |
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14963807 |
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PCT/JP2011/061712 |
May 23, 2011 |
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13685472 |
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Current U.S.
Class: |
215/44 ;
215/43 |
Current CPC
Class: |
B65D 1/0246 20130101;
B29C 71/02 20130101; B65D 1/023 20130101; B29C 49/6409 20130101;
B29K 2995/0041 20130101; B29C 71/0063 20130101; B29D 22/003
20130101; B29C 35/0266 20130101; B29C 49/76 20130101; B29K 2105/258
20130101 |
International
Class: |
B29C 49/76 20060101
B29C049/76; B29C 71/00 20060101 B29C071/00; B65D 1/02 20060101
B65D001/02; B29C 49/64 20060101 B29C049/64 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2010 |
JP |
2010-122898 |
Claims
1.-10. (canceled)
11. A wide-neck container that is made of a synthetic resin
comprising: a neck; a body; and a bottom, wherein the wide-neck
container is configured so that a top side of the neck is sealed by
a cap that is fitted to the neck, wherein the neck includes: a neck
tubular section; an engagement section that is formed to protrude
outward from the neck tubular section, and engages the cap; and a
flange that is formed to protrude outward from the neck tubular
section at the top side, a protrusion height of the flange from the
neck tubular section being smaller than that of the engagement
section, wherein the top side of the neck includes a first top side
formed by the neck tubular section, and a second top side formed by
the flange that is the same height level with the first top side
and increases an area of the top side of the neck, wherein the neck
tubular section has a uniform thickness at an area immediately
below the flange and an area where the engagement section is
formed, wherein a thickness of the flange is smaller than that of
the neck tubular section, and wherein the neck have been
crystallized.
12. The wide-neck container as defined in claim 11, wherein the
flange includes an opposite side that is opposite to the second top
side, and the second top side has a higher resin density than that
of the opposite side.
13. The wide-neck container as defined in claim 11, wherein the
engagement section includes N (N is an integer equal to or larger
than 2) threads, and the N threads are respectively provided in N
segmented areas into which the neck tubular section is divided in a
circumferential direction, and are respectively formed in the N
segmented areas within a range of less than 360.degree./N.
14. The wide-neck container as defined in claim 13, wherein each of
the N threads extends from a start point that is positioned at a
first height in an axial direction of the neck tubular section to
an end point that is positioned at a second height in the axial
direction of the neck tubular section so that each of the N threads
slopes upward toward the top side of the neck.
15. A wide-neck container that is made of a synthetic resin
comprising: a neck; a body; and a bottom, the wide-neck container
being configured so that a top side of the neck is sealed by a cap
that is fitted to the neck, wherein the neck includes: a neck
tubular section; an engagement section that is formed to protrude
outward from the neck tubular section, and engages the cap; and a
ring-shaped recess that is formed in the neck tubular section at a
height position closer to the body than the engagement section.
16. The wide-neck container as defined in claim 15, wherein the
engagement section includes N (N is an integer equal to or larger
than 2) threads, and the N threads are respectively provided in N
segmented areas into which the neck tubular section is divided in a
circumferential direction, and are respectively formed in the N
segmented areas within a range of less than 360.degree./N.
17. The wide-neck container as defined in claim 16, wherein each of
the N threads extends from a start point that is positioned at a
first height in an axial direction of the neck tubular section to
an end point that is positioned at a second height in the axial
direction of the neck tubular section so that each of the N threads
slopes upward toward the top side of the neck.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Patent
Application No. PCT/JP2011/061712, having an international filing
date of May 23, 2011, which designated the United States and which
claims priority from Japanese Patent Application No. 2010-122898
filed on May 28, 2010, the entirety of both of which are
incorporated herein by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to a preform neck
crystallization method and the like.
[0004] 2. Description of the Related Art
[0005] A wide-neck (wide-mouth) container has a structure in which
the ratio of the outer diameter of the neck to the outer diameter
of the body is larger than that of a narrow-neck (narrow-mouth)
container (e.g., polyethylene terephthalate (PET) bottle) that is
widely used as a beverage container. For example, a container
having a neck outer diameter of 45 mm or more is generally referred
to as "wide-neck container". Since the wide-neck container allows
easy removal of the contents, the wide-neck container has been used
as a solid (e.g., jam) container in addition to a liquid
container.
[0006] The wide-neck container normally employs a top-side seal
structure (i.e., the top side of the neck is sealed using a cap).
Therefore, deformation of the top side of the neck must be as small
as possible in order to improve the seal-tightness.
[0007] In particular, when the wide-neck container is subjected to
a high-temperature filling operation, it is necessary to
crystallize the neck (i.e., increase the density of the neck) so
that the neck exhibits heat resistance. When crystallizing the
neck, the volume of the neck decreases along with an increase in
density, so that deformation of the neck easily occurs. It is
necessary to prevent a situation in which such deformation
adversely affects the top side of the neck.
[0008] Japanese Utility Model Registration No. 3064403 and
JP-A-2006-297775 disclose a neck crystallization method that heats
the neck from the inner side and the outer side, and
JP-A-11-152122, JP-A-2004-26201, and JP-A-2004-131175 disclose
deformation of the neck of a narrow-neck container.
[0009] In Japanese Utility Model Registration No. 3064403 and
JP-A-2006-297775, a core is inserted into the neck of a narrow-neck
preform to heat the neck of the narrow-neck preform from the inner
side and the outer side. In Japanese Utility Model Registration No.
3064403, a second heat source (22) that heats a thermal conductor
(21) that is part of a core that extends outward from the neck is
provided in addition to a first heat source (12) that heats the
neck from the outer side, and heat from the second heat source (22)
is transmitted to the core to heat the neck from the inner side
(see FIG. 7). In JP-A-2006-297775, the second heat source (22)
disclosed in Japanese Utility Model Registration No. 3064403 is
omitted, and the thermal conductor (21) disclosed in Japanese
Utility Model Registration No. 3064403 is replaced with a fin (12a)
to heat the neck from the outer side. Heat retained by the internal
heating core is dissipated through the fin (12a) to achieve the
balance between internal heating and external heating (see FIG.
4).
[0010] However, when using the method that supplies heat to the
core (Japanese Utility Model Registration No. 3064403) or the
method that promotes dissipation of heat from the core
(JP-A-2006-297775), the neck crystallization temperature
predominantly depends on the temperature of the heat source
provided outside the neck (i.e., internal heating using the core is
subsidiary). Japanese Utility Model Registration No. 3064403
focuses on the temperature gradient between the inner wall and the
outer wall of the neck (see FIGS. 5 and 6), and JP-A-2006-297775
maintains the temperature between the inner wall and the outer wall
of the neck constant by combining rapid external heating and heat
dissipation using the fin (see paragraph 0058). However, Japanese
Utility Model Registration No. 3064403 and JP-A-2006-297775 are
silent about a change in temperature with time from room
temperature to the crystallization temperature.
SUMMARY
[0011] The invention may provide a neck crystallization method that
can reduce the crystallization time, and control the temperature of
the neck at an optimum crystallization temperature (i.e., a
temperature at which the neck is not overheated) while heating the
inner side and the outer side of the neck.
[0012] According to one aspect of the invention, there is provided
a preform neck crystallization method that crystallizes a neck of a
preform that includes the neck, a body, and a bottom, the method
comprising:
[0013] inserting a core into the neck;
[0014] heating the neck using a heater group disposed along a
transfer direction while rotating the preform on its axis, and
transferring the preform along the transfer direction in a state in
which the core is inserted into the neck; and
[0015] cooling the neck of the preform in a state in which the core
is inserted into the neck,
[0016] the heating of the neck including:
[0017] a first step that drives first heaters within the heater
group at a first power, the first heaters being positioned on an
upstream side in the transfer direction; and
[0018] a second step that drives second heaters within the heater
group at a second power that is lower than the first power until a
temperature of the neck reaches a crystallization temperature zone,
the second heaters being positioned on a downstream side of the
first heaters.
[0019] According to one aspect of the invention, the
crystallization time can be reduced while preventing a situation in
which the neck is overheated to a temperature that exceeds the
crystallization temperature zone by combining the rapid-heating
first step and the slow-heating second step. When using only the
first step, the crystallization time can be reduced, but the neck
is overheated in the second half of the heating step. When using
only the second step, the crystallization time can be controlled,
but increases. Since the neck of the preform is at room temperature
immediately after the preform has been supplied, the
crystallization time can be reduced by rapidly heating the neck by
the first step up to a temperature lower than the crystallization
temperature zone.
[0020] The preform neck crystallization method may further
comprise:
[0021] transferring the preform without heating between the first
step and the second step.
[0022] The temperature of the neck of the preform decreases by
transferring the preform without heating between the first step and
the second step. Therefore, the effect of rapid heating in the
first step can be suppressed (reduced) when starting the second
step. This makes it possible to cause the temperature of the neck
of the preform to rise less steeply as compared with the first step
immediately after starting the second step.
[0023] The preform neck crystallization method may further
comprise:
[0024] a third step that drives third heaters within the heater
group at a third power that is lower than the second power to
maintain the temperature of the neck within the crystallization
temperature zone, the third heaters being positioned on a
downstream side of the second heaters.
[0025] It is possible to easily maintain the temperature of the
neck within the crystallization temperature zone by further
reducing the heater power after the temperature of the neck has
reached the crystallization temperature zone. This makes it
possible to prevent a situation in which the neck is
overheated.
[0026] In the preform neck crystallization method,
[0027] the third step may include reducing the third power that
drives the third heaters on a downstream side in the transfer
direction compared to an upstream side in the transfer
direction.
[0028] It is possible to maintain the temperature of the neck
within the crystallization temperature zone by thus reducing the
power on the downstream side to maintain or decrease the
temperature increase rate.
[0029] The preform neck crystallization method may further
comprise:
[0030] preheating the core before inserting the core into the
neck.
[0031] This makes it possible to allow the temperature of the core
to be substantially equal to the outer surface temperature of the
neck (i.e., sufficiently reduce the difference in temperature
between the inner side and the outer side of the neck) when staring
the second step. The above configuration also has an advantage in
that the time of the first step can be reduced.
[0032] According to another aspect of the invention, there is
provided a wide-neck container that is made of a synthetic resin,
and includes a neck, a body, and a bottom, the wide-neck container
being configured so that a top side of the neck is sealed by a cap
that is fitted to the neck,
[0033] the neck including:
[0034] a neck tubular section;
[0035] an engagement section that is formed to protrude outward
from the neck tubular section, and engages the cap; and
[0036] a flange that is formed to protrude outward from the neck
tubular section at the top side, a protrusion height of the flange
from the neck tubular section being smaller than that of the
engagement section,
[0037] the top side of the neck including a first top side formed
by the neck tubular section, and a second top side formed by the
flange that is the same height level with the first top side and
increases an area of the top side of the neck,
[0038] a thickness of the flange being smaller than that of the
neck tubular section, and the neck having been crystallized.
[0039] According to this aspect of the invention, the seal area can
be increased by the top side having an increased area, and the
resin density of the top side of the flange can be increased due to
the resin pressure in the resin flow direction during injection
molding. Therefore, deformation of the top side during
crystallization is reduced, so that the seal-tightness with the cap
can be improved. The flange may also be used as a member that
engages a chuck that transfers the preform, and prevents
displacement of the preform in the axial direction.
[0040] In the wide-neck container, the flange may have an opposite
side that is opposite to the second top side, and the second top
side may have a higher resin density than that of the opposite
side.
[0041] Deformation of the top side of the flange used for sealing
can be suppressed by thus allowing the opposite side having a low
resin density to be deformed when crystallizing the neck.
[0042] According to another aspect of the invention, there is
provided a wide-neck container that is made of a synthetic resin,
and includes a neck, a body, and a bottom, the wide-neck container
being configured so that a top side of the neck is sealed by a cap
that is fitted to the neck,
[0043] the neck including:
[0044] a neck tubular section;
[0045] an engagement section that is formed to protrude outward
from the neck tubular section, and engages the cap; and
[0046] a ring-shaped recess that is formed in the neck tubular
section at a height position closer to the body than the engagement
section.
[0047] According to this aspect of the invention, since the
ring-shaped recess is formed to be depressed in the neck tubular
section, the amount of resin used to form the preform can be
reduced. Since the amount of shrinkage of the neck during
crystallization can be reduced by reducing the volume of the neck,
deformation of the top side of the neck can be suppressed, so that
the top-side seal-tightness can be improved. The ring-shaped recess
may also be used as a member that engages a chuck that transfers
the preform, and prevents displacement of the preform in the axial
direction.
[0048] In the wide-neck container according to each aspect, the
engagement section may include N (N is an integer equal to or
larger than 2) threads, and the N threads may be respectively
provided in N segmented areas into which the neck tubular section
is divided in a circumferential direction, and may be respectively
formed in the N segmented areas within a range of less than
360.degree./N.
[0049] According to the above configuration, since each engagement
section is provided in one row (i.e., two or more engagement
sections are not arranged in the axial direction) around the neck
tubular section, the volume of the engagement section that
protrudes from the neck tubular section is reduced. Since the
amount of shrinkage of the neck during crystallization can be
reduced by reducing the volume of the neck, deformation of the top
side of the neck can be suppressed, so that the top-side
seal-tightness can be improved.
[0050] In the wide-neck container according to each aspect, each of
the N threads may extend from a start point that is positioned at a
first height in an axial direction of the neck tubular section to
an end point that is positioned at a second height in the axial
direction of the neck tubular section so that each of the N threads
slopes upward toward the top side of the neck.
[0051] According to the above configuration, since the N threads
are not connected spirally, but have the start point having an
identical height and the end point having an identical height in
the respective N segmented areas, the height of the neck tubular
section can be reduced (i.e., the volume of the neck tubular
section can be reduced). Since the amount of shrinkage of the neck
during crystallization can also be reduced, deformation of the top
side of the neck can be suppressed, so that the top-side
seal-tightness can be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] FIG. 1 is a front view illustrating a wide-neck container
according to a first embodiment of the invention.
[0053] FIG. 2 is a cross-sectional view illustrating a cap that is
fitted to the neck of the wide-neck container illustrated in FIG.
1.
[0054] FIG. 3 is a cross-sectional view illustrating the neck of
the wide-neck container illustrated in FIG. 1, and an example of a
chuck that supports the neck.
[0055] FIG. 4 is a cross-sectional view illustrating the neck of
the wide-neck container illustrated in FIG. 1, and another example
of a chuck that supports the neck.
[0056] FIG. 5 is a cross-sectional view illustrating a preform
injection molding step employed for the wide-neck container
illustrated in FIG. 1.
[0057] FIG. 6 is a front view illustrating a wide-neck container
according to a second embodiment of the invention.
[0058] FIG. 7 is a cross-sectional view illustrating the neck of
the wide-neck container illustrated in FIG. 6.
[0059] FIG. 8 is an end view illustrating threads of the wide-neck
containers illustrated in FIGS. 1 and 6.
[0060] FIGS. 9A to 9D are views illustrating the main steps of a
neck crystallization method.
[0061] FIG. 10 is a characteristic diagram illustrating a change in
surface temperature of a neck and a change in temperature of a core
within one cycle.
[0062] FIG. 11 is a plan view schematically illustrating a neck
crystallization system.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0063] Exemplary embodiments of the invention are described in
detail below. Note that the following exemplary embodiments do not
in any way limit the scope of the invention defined by the claims
laid out herein. Note that all of the elements described in
connection with the following exemplary embodiments should not
necessarily be taken as essential elements of the invention.
1. First Embodiment
[0064] FIG. 1 is a front view illustrating a wide-neck container
according to a first embodiment of the invention, FIG. 2 is a
cross-sectional view illustrating a cap that is fitted to the neck
of the wide-neck container illustrated in FIG. 1, and FIGS. 3 and 4
are cross-sectional views illustrating the neck of the wide-neck
container and a chuck that supports the neck. As illustrated in
FIG. 1, a wide-neck container 10A made of a synthetic resin (e.g.,
polyethylene terephthalate) includes a neck 20A, a body 30, and a
bottom 40. A top side 21A of the neck 20A is sealed by a cap 90
(see FIG. 2) that is fitted to the neck 20A.
[0065] A twist-off cap or a lug cap may be used as the cap 90 that
is fitted to the neck 20A of the wide-neck container 10A, for
example. The cap 90 is formed to have a bottomed tubular shape (see
FIG. 2), and may include a plurality of (e.g., four) lugs 92 that
protrude from an inner circumferential surface 91 of the tubular
cap 90, and a seal section 93 that is positioned at the bottom of
the cap 90. The seal section 93 may be formed to have a small
thickness (see FIG. 2) so that the seal section 93 exhibits
elasticity, or may be formed by bonding an elastic seal
material.
[0066] The neck 20A includes a neck tubular section 22, and a
plurality of engagement sections 23 that are formed to protrude
outward from the neck tubular section 22, and respectively engage
the plurality of lugs 92 of the cap 90. Each engagement section 23
may be formed by a thread, for example. The neck 20A also includes
a flange 24 that is formed to protrude outward from the neck
tubular section 22 at the top side 21A, the protrusion height of
the flange 24 from the neck tubular section 22 being smaller than
that of each engagement section 23. The neck 20A may further
include a support ring (also referred to as "neck ring") 25. Note
that the support ring 25 is not an essential element (described
later).
[0067] The top side 21A of the neck 20A includes a first top side
22A of the neck tubular section 22, and a second top side 24A of
the flange 24 that is the same height level with the first top side
22A and increases the area of the top side 21A. Note that the side
(lower side) of the flange 24 opposite to the second top side 24A
is referred to as an opposite side 24B. The thickness T2 of the
flange 24 (i.e., the distance between the second top side 24A and
the opposite side 24B) is smaller than the thickness T1 of the neck
tubular section 22 (T1>T2). Note that the neck 20A has been
crystallized (whitened). An example of the crystallization method
is described later.
[0068] Since the neck 20A of the wide-neck container 10A does not
require a locking ring (also referred to as "bead ring") that is
required for a narrow-neck container, the total height of the neck
20A from the top side 21A to the lower side of the support ring 25
can be reduced to 15 mm or less, for example. This makes it
possible to reduce the amount of resin used to produce a preform
that is blow-molded into the container 10A. Since the amount of
shrinkage of the neck 20A during crystallization (whitening) can be
reduced by reducing the volume of the neck 20A, deformation of the
top side 21A of the neck 20A can be suppressed. When a locking ring
is provided to protrude from the neck tubular section 22, the
locking ring easily shrinks during crystallization (whitening), and
may cause deformation of the top side 21A. According to the first
embodiment, it is possible to eliminate such an adverse effect of
the locking ring.
[0069] Since the neck 20A of the wide-neck container 10A includes
the flange 24 at the top side 21A, the top-side seal-tightness is
improved. The top-side seal-tightness depends on the flatness and
the area of the top side. According to the first embodiment, both
the flatness and the area of the top side are improved (or
increased) for the following reasons.
[0070] Specifically, the top side 21A includes the first top side
22A of the neck tubular section 22, and the second top side 24A of
the flange 24 that is the same height level with the first top side
22A and increases the area of the top side 21A. Therefore, when the
cap 90 illustrated in FIG. 2 is fitted to the neck 20A, the seal
area is increased due to the top side 21A that is enlarged by the
second top side 24A, so that the seal-tightness with the seal
section 93 of the cap 90 can be improved. This is the first reason
why the top-side seal-tightness is improved.
[0071] The flange 24 increases the density of the resin that forms
the top side 21A, and reduces deformation of the top side 21A. FIG.
5 illustrates a process that injection-molds the neck 20A by
injecting a resin into a cavity formed between an injection core
mold 50 and a neck cavity mold 51. The resin is injected at a given
resin pressure from the bottom side of a preform for blow-molding
the container 10A along a resin flow direction A indicated by an
arrow A. In this case, while a resin pressure B is applied directly
to the molding surface for the wide top side 21A along the resin
flow direction A, a resin pressure C is applied to the molding
surface for the narrow opposite side 24B in the direction opposite
to the resin flow direction A. Therefore, the resin pressure C is
lower than the resin pressure B.
[0072] Since the top side 21A comes in contact with the injection
core mold 50 over a wide area, the top side 21A is cooled with high
cooling efficiency. In contrast, since the opposite side 24B is
narrow, and is cooled in a state in which the opposite side 24B
comes in contact with the protrusion of the neck cavity mold 51,
the opposite side 24B is cooled with low cooling efficiency.
[0073] Accordingly, the second top side 24A (top side 21A) has a
higher resin density than that of the opposite side 24B. The resin
density further increases as a result of crystallizing the neck
20A. The second top side 24A (top side 21A) still has a higher
resin density than that of the opposite side 24B after
crystallizing the neck 20A. The top side 21A rarely shrinks, and
exhibits improved flatness due to an increase in resin density. If
the resin density is low in an amorphous state before
crystallization, a large amount of shrinkage occurs during the heat
treatment. According to the first embodiment, shrinkage
(deformation) of the second top side 24A (top side 21A) is reliably
suppressed while allowing the opposite side 24B to shrink (deform)
to some extent. This is the second reason why the top-side
seal-tightness is improved.
[0074] The flange 24 also serves as a member that prevents
displacement of a chuck member 60A or 60B (see FIG. 3 or 4) in the
axial direction. The wide-neck container 10A or the preform is
supported in an upright state (i.e., a state in which the neck 20A
faces upward) by supporting the lower side of the support ring 25
when transferring the wide-neck container 10A or the preform
without using the neck cavity mold, and is otherwise supported
using the chuck member 60A illustrated in FIG. 3 or the chuck
member 60B illustrated in FIG. 4. The chuck member 60 holds the
engagement sections (threads) 23 from either side. The chuck member
60 may include a protrusion 61 that enters the space between the
engagement section (thread) 23 and the flange 24 in order to
prevent displacement of the container 10A in the axial direction.
According to the example illustrated in FIG. 3, the support ring 25
can be made unnecessary by transferring the container 10A in an
upright state while supporting the flange 24 instead of the support
ring 25, or transferring the container 10A in an inverted state.
The chuck member 60B illustrated in FIG. 4 may include a protrusion
62 that comes in contact with the flange 24, and a protrusion 63
that comes in contact with the support ring 25 in order to prevent
displacement of the container 10A in the axial direction.
2. Second Embodiment
[0075] FIG. 6 is a front view illustrating a wide-neck container
according to a second embodiment of the invention, and FIG. 7 is a
cross-sectional view illustrating the neck of the wide-neck
container illustrated in FIG. 6. As illustrated in FIG. 6, a
wide-neck container 10B made of a synthetic resin includes a neck
20B, a body 30, and a bottom 40. A top side 21B of the neck 20B is
sealed by the cap 90 (see FIG. 2) that is fitted to the neck 20B.
The neck 20B includes the neck tubular section 22, the engagement
sections (threads) 23, and the support ring 25 in the same manner
as in the first embodiment, but does not include the flange 24.
Note that the neck 20B may also include the flange 24. The neck 20B
includes a ring-shaped recess 6 that is formed in the neck tubular
section 22 at a height position closer to the body 30 than the
engagement sections 23. Note that the support ring 25 is not an
essential element in the same manner as in the first
embodiment.
[0076] The neck 20B of the wide-neck container 10B does not require
a locking ring that is required for a narrow-neck container, and
includes the ring-shaped recess 26 that can be reduced in vertical
dimension as compared with (the height of) a locking ring. This
makes it possible to reduce the total height of the neck 20B from
the top side 21B to the lower side of the support ring 25, and
reduce the amount of resin used to form a preform for blow-molding
the container 10B. Since the amount of shrinkage of the neck 20B
during crystallization (whitening) can be reduced by reducing the
volume of the neck 20B, deformation of the top side 21B of the neck
20B can be suppressed. When a locking ring is provided to protrude
from the neck tubular section 22, the locking ring easily shrinks
during crystallization (whitening), and may cause deformation of
the top side 21B. According to the second embodiment, since the
ring-shaped recess 26 is formed in the neck tubular section 22, it
is possible to suppress such an adverse effect of shrinkage.
[0077] The ring-shaped recess 26 also serves as an engagement
section that engages a chuck member 70 (see FIG. 4). The wide-neck
container 10B or the preform is supported in an upright state
(i.e., a state in which the neck 20B faces upward) by supporting
the lower side of the support ring 25 when transferring the
wide-neck container 10B or the preform without using the neck
cavity mold, and is otherwise supported using the chuck member 70.
The chuck member 70 holds the engagement sections (threads) 23 from
either side. The chuck member 70 may include a protrusion 71 that
enters the ring-shaped recess 26 in order to prevent displacement
of the container 10B in the axial direction. The support ring 25
can be made unnecessary by transferring the container 10B in an
inverted state instead of transferring the container 10B in an
upright state.
3. Thread Shape that Suppresses Deformation of Top Side of Neck
[0078] FIG. 8 is an end view (from the top side 21A or 21B)
illustrating the engagement sections (threads) 23 of the container
10A or 10B illustrated in FIG. 1 or 6. Note that the flange 24 (see
FIG. 1) is omitted in FIG. 8.
[0079] In the first embodiment and the second embodiment, the
engagement sections 23 include N (N is an integer equal to or
larger than 2 (preferably 4.ltoreq.N.ltoreq.6) (N=4 in the first
embodiment and the second embodiment) threads 23A to 23D (three
threads are illustrated in FIGS. 1 and 6) (see FIGS. 1, 6, and 8).
The N (=4) threads 23A to 23D are respectively provided in N
segmented areas into which the neck tubular section 22 is divided
in the circumferential direction (.theta.1=90o), the threads 23A to
23D being respectively formed in the N segmented areas within an
angle .theta.2 of less than 360o/N. When N=4, the threads 23A to
23D are respectively formed within an angular range of less than
90o (.theta.2<90o). Each of the N (=4) threads 23A to 23D
extends from a start point 23-1 that is positioned at a first
height H1 in the axial direction of the neck tubular section 22 to
an end point 23-2 that is positioned at a second height H2 in the
axial direction of the neck tubular section 22 (i.e., each of the N
(=4) threads 23A to 23D slopes upward toward the top side 21A (21B)
of the neck 20A (20B)).
[0080] When fitting the cap 90 illustrated in FIG. 2 to the neck
20A (20B) that includes the multiple threads 23A to 23D, the four
lugs 92 of the cap 90 are fitted to the multiple (four to six)
threads 23A to 23D. For example, the wide-neck container 10A (10B)
can be opened or closed by turning the cap 90 by 1/4th to 1/6th of
a turn.
[0081] Since the engagement sections (threads) 23 of the container
10A or 10B (see FIG. 1 or 6) are formed to protrude from the neck
tubular section 22, shrinkage of the engagement sections (threads)
23 adversely affects the top side 21A (21B) during heat treatment
for crystallization as the volume of the engagement sections
(threads) 23 increases.
[0082] In the first embodiment and the second embodiment, the
engagement sections (threads) 23 are formed so that the four
threads 23A to 23D are respectively provided in the N segmented
areas into which the neck tubular section 22 is divided in the
circumferential direction (.theta.1=90o). Therefore, the volume of
the engagement sections (threads) 23 is sufficiently small as
compared with the case where two or more threads are arranged in
the axial direction of the neck tubular section 22, so that
deformation of the top side 21A (21B) can be suppressed.
[0083] In the first embodiment and the second embodiment, the
engagement sections (threads) 23 are formed so that the four
threads 23A to 23D are respectively formed within an angular range
of less than 90o (.theta.2<90o). Specifically, a clearance is
necessarily formed between adjacent threads among the four threads
23A to 23D that are not continuously formed in the circumferential
direction. This makes it possible to further reduce the volume of
the engagement sections (threads) 23, and suppress deformation of
the top side 21A (21B).
[0084] The engagement sections (threads) 23 have the following
advantageous effect on the wide-neck container 10B according to the
second embodiment. As illustrated in FIG. 7, the protrusion 71 of
the chuck member 70 is fitted into the ring-shaped recess 26 of the
neck 20B, and prevents a situation in which the neck 20B held by
the chuck member 70 falls.
[0085] The depth of the ring-shaped recess 26 is limited to an
upper-limit value taking account of the thickness of the neck
tubular section 22. If the depth of the ring-shaped recess 26
exceeds the upper-limit value, the flow of a resin that forms the
neck tubular section 22 may be hindered in an area of the
ring-shaped recess 26 when injection-molding a preform, so that a
short shot or the like may occur. The thickness of the neck tubular
section 22 is also limited from the viewpoint of reducing the
amount of resin. For example, when the thickness of the neck
tubular section 22 is set to 1.5 mm, the upper-limit value of the
depth of the ring-shaped recess 26 is 0.5 mm. As a result, the
chuck member 70 illustrated in FIG. 7 may be removed from the
ring-shaped recess 26 due to the weight of the preform, for
example.
[0086] According to the first embodiment and the second embodiment,
each of the N (=4) threads 23A to 23D extends from the start point
23-1 that is positioned at the first height H1 in the axial
direction of the neck tubular section 22 to the end point 23-2 that
is positioned at the second height H2 in the axial direction of the
neck tubular section 22 (i.e., each of the N (=4) threads 23A to
23D slopes upward toward the top side 21A (21B) of the neck 20A
(20B)). More specifically, the four threads 23A to 23D respectively
include the start point 23-1 that is positioned at the first height
H1 directly above the ring-shaped recess 26 at different positions
in the circumferential direction of the neck tubular section
22.
[0087] Therefore, even if the chuck member 70 illustrated in FIG. 7
has been removed from the ring-shaped recess 26, the four start
points 23-1 that protrude at the first height position H1 at four
points in the circumferential direction of the neck tubular section
22 are caught by the protrusion 71 of the chuck member 70. This
makes it possible to prevent a situation in which the neck 20B
falls off from the chuck member 70. Each start point 23-1 thus
functions as a stopper.
4. Neck Crystallization Method
[0088] A neck crystallization method that may be applied to the
wide-neck container 10A (10B) according to the first embodiment or
the second embodiment, and may also be applied to another wide-neck
container or a narrow-neck container, is described below. FIGS. 9A
to 9D are views illustrating the main steps of the neck
crystallization method, and FIG. 10 is a characteristic diagram
illustrating a change in surface temperature of the neck and a
change in temperature of the core within one cycle.
[0089] A preform 100 (e.g., wide-neck container preform) that has
been injection-molded is transferred to a neck crystallization
system (see FIG. 9A). Note that the neck crystallization system may
be used to crystallize the neck of a blow-molded container instead
of crystallizing the neck of a preform. In this case, however, it
is necessary to use a larger system in order to transfer a
container that is larger than a preform.
[0090] The preform 100 includes a neck 101, a body 102, and a
bottom 103. The neck 101 of the preform 100 that is not blow-molded
may have the structure of the neck 20A illustrated in FIG. 1, the
structure of the neck 20B illustrated in FIG. 6, or another neck
structure.
[0091] FIG. 9A illustrates a step that inserts a core 110 into the
neck 101 of the preform 100. The preform 100 is transferred while
being placed on a tubular body 120 in an inverted state before the
core 110 is inserted into the neck 101 of the preform 100. The core
110 is secured on an elevating rod 130, and a pad 132 is secured on
the upper end of the elevating rod 130. FIG. 9A illustrates a state
in which the core 110 is disposed inside the neck 101 of the
preform 100, and the preform 100 is slightly moved upward by the
pad 132, and is separated from the tubular body 120 by moving the
elevating rod 130 upward.
[0092] The core 110 is formed by disposing an outer layer 114 that
is formed of a material having either or both of an infrared
absorption function and an infrared reflection function on the
circumferential surface of an insulator 112. The outer layer 114 is
formed of a metal, for example. In one embodiment of the invention,
the outer layer 114 is formed of aluminum (Al). The core 110 does
not have a heat source, and heats the neck 101 from the inner side
by reflecting infrared radiation from a heater (e.g., infrared
heater 140) (described later), or utilizing heat retained by the
core 110. The difference in temperature between the inner side and
the outer side of the neck 101 can be reduced while reducing the
crystallization time by combining internal heating using the core
110 and external heating using the infrared heater 140. Moreover,
since the core 110 that is transferred together with the preform
100 need not have a heat source, it is unnecessary to use a complex
system.
[0093] The core 110 may include a heat shield plate 116 that is
provided on the upper side of the core 110 and blocks (e.g.,
reflects) heat. A situation in which heat is transmitted to the
body 102 can be prevented by providing the heat shield plate
116.
[0094] FIG. 9B illustrates a heating step. In FIG. 9B, the neck 101
is heated using the infrared heater 140 while rotating the preform
100 on its axis, and transferring the preform 100 along the
transfer direction in a state in which the core 110 is inserted
into the neck 101. A plurality of infrared heaters 140 (hereinafter
referred to as "infrared heater group 200") are provided along
preform transfer directions A1 and A2 illustrated in FIG. 11. FIG.
9B illustrates a state in which the infrared heaters 140 are
disposed opposite to each other on either side of the transfer
path, and uniformly heat the neck 101 of the rotating preform 100
from the outside. In the heating step, the body 102 of the preform
100 may be shielded from heat from the infrared heater 130 by
disposing a heat shield tubular body 150 around the body 102 (see
FIG. 9B).
[0095] FIG. 9C illustrates a step that cools the neck 101 of the
preform 100 in a state in which the core 110 is inserted into the
neck 101. The cooling step may be implemented by air cooling while
rotating the preform 100, or may be implemented by forced cooling
using a refrigerant. The core 110 prevents (restricts) shrinkage
(deformation) of the neck 101 during the cooling step.
[0096] FIG. 9D illustrates a step that removes the core 110 from
the neck 101 of the preform 100. The preform 100, of which the neck
has been crystallized, is removed from the tubular body 120 to
complete one cycle of the neck crystallization method.
[0097] The heating step is described below with reference to FIGS.
10 and 11. FIG. 11 is a plan view schematically illustrating the
transfer path of the preform 100 and the infrared heater group 200.
The preform is supplied at a position P1, continuously or
intermittently transferred and heated along the transfer directions
A1 and A2, and cooled in a cooling zone 220. The preform 100, of
which the neck has been crystallized, is removed at a position
P2.
[0098] The heating step includes a first step that drives first
infrared heaters 200-1 within the infrared heater group 200
illustrated in FIG. 11 at a first power, the first infrared heaters
200-1 being positioned on the upstream side in the transfer
direction. In the first step illustrated in FIG. 10, the first
power that drives the first infrared heaters 200-1 is set to 70% of
full power, for example. The surface temperature TS of the neck 101
of the preform 100 (see FIG. 10) increases relatively steeply per
unit time.
[0099] The heating step may further include a second step that
drives second infrared heaters 200-2 within the infrared heater
group 200 illustrated in FIG. 11 that are positioned on the
downstream side of the first infrared heaters 200-1 at a second
power that is lower than the first power, and heats the neck 101
using the second infrared heaters 200-2 and the core 110 until the
temperature of the neck 101 reaches a crystallization (whitening)
temperature zone (e.g., 170 to 190oC). In the second step
illustrated in FIG. 10, the second power that drives the second
infrared heaters 200-2 is set to 60% of full power, for example.
The surface temperature TS of the neck 101 of the preform 100 (see
FIG. 10) increases less steeply per unit time as compared with the
first step.
[0100] The rapid-heating first step and the slow-heating second
step are combined in order to reduce the crystallization time while
preventing a situation in which the neck 101 is overheated. When
using only the first step, the crystallization time can be reduced,
but the neck 101 is overheated in the second half of the heating
step. When using only the second step, the crystallization
temperature can be controlled, but the crystallization time
increases. Since the neck 101 of the preform 100 is at room
temperature immediately after the preform 100 has been supplied,
the crystallization time can be reduced by rapidly heating the neck
101 by the first step up to a temperature lower than the
crystallization temperature zone.
[0101] As illustrated in FIG. 10, a step that transfers the preform
without heating may be provided between the first step and the
second step. In FIG. 11, a non-heating zone 210 in which heaters
are not provided, or heaters that are not driven are disposed, is
provided between the first heaters 200-1 and the second heaters
200-2. The surface temperature TS of the neck 101 of the preform
100 decreases due to the non-heating zone 210 (see FIG. 10).
Therefore, the effect of rapid heating in the first step can be
suppressed (reduced) when starting the second step. This makes it
possible to cause the surface temperature TS of the neck 101 of the
preform 100 to increase less steeply as compared with the first
step when starting the second step.
[0102] The heating step may further include a third step that
drives third infrared heaters 200-3 and 200-4 within the infrared
heater group 200 illustrated in FIG. 11 that are positioned on the
downstream side of the second infrared heaters 200-2 at a third
power that is lower than the second power, and heats the neck 101
using the infrared heaters 200-3 and 200-4 and the core 110 while
maintaining the temperature of the neck 101 within the
crystallization (whitening) temperature zone. In the third step
illustrated in FIG. 10, the third power that drives the third
infrared heaters 200-3 and 200-4 is set to 50 to 55% of full power,
for example. It is possible to easily maintain the temperature of
the neck 101 within the crystallization temperature zone by further
reducing the heater power after the temperature of the neck 101 has
reached the crystallization temperature zone. This makes it
possible to prevent a situation in which the neck 101 is
overheated.
[0103] In the third step, the third power that drives the third
infrared heaters 200-3 and 200-4 (see FIG. 11) may be reduced on
the downstream side in the transfer direction as compared to the
upstream side in the transfer direction. In the example illustrated
in FIG. 10, the power that drives the upstream-side third infrared
heaters 200-3 is set to 55% of full power, and the power that
drives the downstream-side third infrared heaters 200-4 is set to
50% of full power. It is possible to maintain the temperature of
the neck 101 within the crystallization temperature zone by
reducing the power on the downstream side in the transfer direction
to maintain the temperature increase rate (see FIG. 10), or
decrease the temperature increase rate. This makes it possible to
prevent a situation in which the neck 101 is overheated in the
third step. In the third step, the third infrared heaters may be
divided into three or more groups instead of dividing the third
infrared heaters into the groups 200-3 and 200-4.
[0104] When the time in which a plurality of preforms 100 pass by
the infrared heaters 200-1 is referred to as T1, and the time in
which a plurality of preforms 100 pass by each of the infrared
heaters 200-2 to 200-4 is referred to as T2, T1>T2 may be
satisfied. When a plurality of preforms 100 are continuously
transferred, for example, the difference between the time T1 and
the time T2 corresponds to the difference in length between the
heating zones. In FIG. 11, the heating zones corresponding to the
infrared heaters 200-1 to 200-4 have an identical length. The
heating time in each heating zone can be changed by changing the
length of each heating zone. When intermittently transferring a
plurality of preforms 100, the heating time in each heating zone
can also be changed by changing the length of each heating zone.
For example, when the time T1 corresponds to three steps of
continuous transfer, the time T2 may be set to two steps of
continuous transfer. It is unnecessary to use an infrared heater
that achieves a very high temperature rise rate when increasing the
temperature of the neck 101 from room temperature to a temperature
that exceeds 100oC by increasing the time T1 of the first step. If
the time T1 of the first step is shorter than the time T2, the
second step may be adversely affected by rapid heating in the first
step, so that it may be difficult to maintain the temperature of
the neck 101 within the crystallization temperature zone, or it may
take time until the temperature of the neck 101 reaches the
crystallization temperature zone.
[0105] The temperature TC of the core 110 is also illustrated in
FIG. 11. FIG. 11 illustrates an example in which the core 110 is
preheated at a position between the positions P1 and P2 before the
core 110 is inserted into the neck 101. Specifically, the neck
crystallization method may further include a step that preheats the
core 110 before inserting the core 110 into the neck 101.
[0106] In the first step (see FIG. 11), infrared radiation from the
infrared heater 140 is applied to the core 110 via the neck 101,
but the temperature of the core 110 decreases due to contact with
the neck 101 that is set at room temperature. In the first step or
the subsequent non-heating step (at the start timing of the second
step), the temperature of the core 110 is substantially equal to
the surface temperature of the neck 101. Specifically, the first
step or the subsequent non-heating step is performed until the
temperature of the outer side of the neck 101 becomes substantially
equal to the temperature of the inner side of the neck 101. In the
second step, the temperature increase rate of the core 110 is low
since the core 110 has a larger heat capacity than the neck 101.
However, since the temperature TC of the core 110 gradually
increases along with an increase in the surface temperature TS of
the neck 101 of the preform 100, the difference in temperature
between the inner side and the outer side of the neck 101 is within
a given range. Note that the step that preheats the core 110 is not
an essential step, but has an advantage in that the time of the
first step can be reduced by preheating the core 110.
[0107] Although only some embodiments of the invention have been
described in detail above, those skilled in the art would readily
appreciate that many modifications are possible in the embodiments
without materially departing from the novel teachings and
advantages of the invention. Accordingly, such modifications are
intended to be included within the scope of the invention. Any term
cited with a different term having a broader meaning or the same
meaning at least once in the specification and the drawings can be
replaced by the different term in any place in the specification
and the drawings.
[0108] Although the invention has been described using specific
terms, devices, and/or methods, such description is for
illustrative purposes of the preferred embodiment(s) only. Changes
may be made to the preferred embodiment(s) by those of ordinary
skill in the art without departing from the scope of the present
invention, which is set forth in the following claims. In addition,
it should be understood that aspects of the preferred embodiment(s)
generally may be interchanged in whole or in part.
* * * * *