Note: Descriptions are shown in the official language in which they were submitted.
1 1 66~75
This invention relates to a biaxially oriented
bottle of saturated polyester resin and a method for
molding the same.
Biaxially oriented bottles of synthetic resin,
particularly saturated polyester resin such as polyethy-
lene terephthalate, are in general use in large quantities
because of the outstanding physical properties and
durability resul.ing from the crystallization of molecules
which occurs when the bottle is subjected to biaxial
orientation in the molding process.
In spite of the superior characteristics, the
biaxially oriented bottles of saturated polyester resin
are not necessarily satisfactory completely when used as
containers for alcoholic liquids.
The great disadvantage of biaxially oriented
bottles of saturated polyester resin is that the mouth
or the part extending from the neck to the shoulder,
which is not oriented or is oriented only a little, is
much poorer in durability and physical properties than
the body which is molded under sufficient orientation.
This disadvantage results from the fact that the bottles
are molded, with few exceptions, by so-called injection
blow molding process in which bottomed cylindrical
parisons are formea by injection molding and subsequently
the parisons are molded into bottles by biaxial orien-
tation blow molding.
., ' ~
,............................. -- 1 --
.~
t l 66t75
The disadvantage resulting from the fact that
the mouth or the part e~tending from the neck to the
shoulder is not oriented manifests itself as whitening
or crazing caused by infiltration of alcohol when the
bottle is filled with a liquid containing alcohol more
than 20~. In addition, the unoriented mouth is too soft
and weak to be sealed by snap-in fitting, and is liable
to deformation due to the tightening force of screw cap.
Heretofore, a variety of means have been employed
in order to improve the durability and physical properties
of the mouth or the part extending from the neck to the
shoulder.
One means includes orientation of the mouth
and neck in radial direction which takes place after
biaxial orientation molding of the body. This produces
satisfactory results to some extent, but involves tech-
nical difficulties in radial orientation with respect
to the orientation equipment and dimensional accuracy
of the neck.
Another means is directed to whitening the
neck by crystallization under proper temperature control~
This has yet a disadvantage of being unable to be employed
for applications where the neck has to be clear as well
as the body, although the neck is made chemically stable
and mechanically strong by crystallization to a certair~
degree. The improvement of mechanical strength by
crystallization is limited for saturated polyester resin
~ l ~6175
which has inherently a low viscosity.
According to this invention, the improvement
in durability and physical properties can be accomplished
without difficulties encountered in the above-mentioned
conventional methods.
Therefore, it is an object of this invention to
provide a method for improving the chemical and mechanical
properties of the mouth, neck, and shoulder of a biaxially
oriented bottle of saturated polyester resin which under-
goes no or little orientation.
It is another object of this invention to
provide a method for integralIy bonding a mouthpiece,
which forms the mouth of the bottle, to the body of the
bottle.
The gist of the invention consists in covering
the mouth or the part extending from the neck to the
shoulder, which is in direct contact with the content
liquid, with a layer which is resistant to alcohol and
other chemicals even without biaxial orientation, in
order to solve the problems inherent in the properties
of saturated polyester resin itself.
Other objects and advantages of the pr~sent
invention will become apparent from the following descrip-
tion taken in conjunction with the accompanying drawings,
wherein:
Fig. 1 is a partly cutaway perspective view of
an example of the mouthpiece used in the invention;
.
."
- 3 -
.
1 166t.75
Fig. 2 is a longitudinal sectional view of the
mouthpiece fitted onto the core, with the molds closed;
Fig. 3 is a longitudinal sectional view of the
parison injection molded in the cavity;
Fig. 4 is a longitudinal sectional view of the
bottle, with the mouthpiece as shown in Fig. 1 fitted to
the mouth;
Fig. 5 is a longitudinal sectional view of the
bottle, with the mouthpiece of different type fitted to
the mouth;
Fig. 6 is a longitudinal sectional view of the
mouthpiece fitted onto the parison prior to biaxial
orientation;
Fig. 7 is a longitudinal sectional view of the
mouthpiece and the shoulder of the bottle after biaxial
orientation of the parison as shown in Fig. 6;
Fig. 8 is a partly cutaway perspective view of
another example of the mouthpiece;
Figs. 9 to 11 are sectional views illustrating
an example in which the mouthpiece as shown in Fig. 8 is
used;
Fig. 9 is a longitudinal sectional view of an
injection molded mouthpiece fitted onto the core;
Fig. 10 is a longitudinal sectional view of
the parison injection molded in the cavity, with the
mouthpiece inserted; and
Fig. 11 is a longitudinal sectional view
1 1 66t75
illustrating the structure of the bottle produced by the
method of this invention.
The present invention will be described
referring to the drawings.
The bottle according to this invention is made
up of a bottle body P' and a mouthpiece 1 molded separately
from the body P'. The cylindrical mouthpiece 1 is snugly
fitted to the inside of a neck P2 of the body P', and
serves practically as a mouth of the bottle. As shown in
Figs. 4 and 5, the mouthpiece 1 fitted to the inside of
the neck P2 of the body P' forms a mouth of the biaxially
oriented bottle. The mouthpiece 1 forming practically a
mouth of the bottle is of cylindrical shape that snugly
fits to the inside of the neck P2 f the body P' or
parison P. The mouthpiece 1 should preferably be provided
with a flange 3 large enough to cover the upper end of
the neck P2 so that the entire part of the mouth which
comes in contact with the content liquid in actual use of
the bottle is formed by the mouthpiece 1. The flange 3
is formed on the top of the body 2 as shown in Fig. 1.
The mouthpiece 1 is molded separately and
independently from the blow molding of the bottle body
P'. The mouthpiece 1 may be produced from several
materials, but should preferably be produced from poly-
ethylene terephthalate resin by biaxial orientation
molding, in view of the strength of fitting to the bottle
body P'.
~ ~ fi6175
The other resins that may be used are polyester
resin having an intrinsic viscosity greater than 1.0,
polybutylene terephthala~e resin, polyvinyl chloride
resin, and acrylonitrile-butadiene-styrene resin. The
mouthpiece may be molded from metallic material, e.g.,
aluminum.
The process for molding the bottle of this
invention is described below. The mouthpiece 1 is molded
in such dimensions that it is snugly fitted onto the
base of the core C on which is molded the parison P
which is subsequently orientation blow molded into the
body P'. The mouthpiece 1 thus prepared is slipped
onto the base of the core C and then the molds K are
closed, as shown in Fig. 1. The parison P is formed by
injecting molten polyethylene terephthalate into the
cavity surrounded by the core C, the molds K, and the
mouthpiece 1. In other words, the parison P is produced
by insert molding, using the mouthpiece 1 as a part of
the molds. Therefore, the mouthpiece 1 and the parison
P are combined closely together. The injection molded
parison P combined with the mouthpiece 1 is subsequently
placed in the blow mold for orientation blow molding.
The firm bonding of the parison P and the
mouthpiece 1 is accomplished by insert molding as men-
tioned above, but the bond strength may be further
increased if the body 2 of the mouthpiece 1 is provided
with a locking part 4, projection or recession, on the
i~66~'75
periphery. The locking part 4 is not necessarily con-
tinuous along the periphery of the body 2, but may be
b,roken.
The locking part 4 is not so important where
the mouthpiece 1 made of biaxially oriented polyethylene
terephthalate is used which is bonded firmly to the
parison P when the parison P is molded. But the locking
part 4 plays an important role in firm bonding where the
mouthpiece 1 made of aluminum is used which is poor in
adhesion to the parison P.
If the mouthpiece 1 is extended beyond the
flange 3 as shown in Fig. 5, the extended part prevents
the content liquid from coming into contact with the
neck P2 f the body P' during pouring, and consequently
protects the neck P2 from deterioration. In addition,
the extended part helps keep sealing effect for a long
period of time in combination with a cap or packing.
Where the mouthpiece 1 made of synthetic resin
is employed, the mouthpiece 1 should preferably be longer
than the neck of the body P', as shown in Fig. 6, so
that the lower part of the mouthpiece 1 covers the inside
of the shoulder near the neck which is less oriented, as
shown in Fig. 7, when the parison P is molded into the
body P' by biaxial orientation.
The extended lower part of the mouthpiece 1 is
able to cover the inside of the neck and shoulder which
do not undergo sufficient orientation, even though the
~ 1 66 ~ 75
mouthpiece 1 is made of a synthetic resin of high vis-
cosity, because such a part is subjected to only a
little orientation.
Fig. 8 shows another example of mouthpiece 1
which covers the inside of the shoulder. In Fig. 8, the
mouthpiece 11 is made up of a cylindrical body 12 having
a smooth inside, an opening 15 at the top of the body 12,
a flange 13 just below the opening 15, and a locking part
14 just below the flange 13. The locking part 14 serves
to ensure bonding between the mouthpiece 11 and the parison
P when the parison P is formed by insert molding, with
the mouthpiece 11 fitted to the core. It may be in the
form of projection or recession. It is not necessarily
continuous as illustrated, but may be broken.
The locking part 14 is provided at a place
corresponding to the neck P2 f the parison P, and the
lower part 16 of the body 12 is extended to cover that
part of the parison P which forms the shoulder P3 when
the parison P is molded into the bottle body P' by
biaxial orientation. In other words, the mouthpiece 11
is long enough to cover the area from the opening 15 at
the top of the bottle body P' to the shoulder P3 near
the neck P2 which does not undergo suf~icient orientation.
The flange 13 is provided in such a manner
that it covers completely the top surface of the parison
P, in order to prevent the content liquid, when poured
out, from coming into contact with the outside of the
A~
-- 8 --
1 166~75
neck P2 as far as possible; but it may be omitted. It
should preferably be provided to ensure stable engagement
between the mouthpiece 11 and the parison P and to rein-
force the mechanical strength of the opening 15.
The mouthpiece 11 may be injection molded from
saturated polyester resin or polybutylene terephthalate
resin having intrinsic viscosity greater than 1.0,
polyvinyl chloride resin, acrylonitrile-butadiene-styrene
resin, etc., which are inherently superior in mechanical
strength and chemical properties such as resistance to
alcohol and chemicals, even without orientation.
The mouthpiece 11 is slipped onto the base of
the core C, as shown in Pig. 9, and the molds K are
closed, with the core C placed therebetween. Saturated
polyester resin of low viscosity is injected from the
gate G into the cavity surrounded by the molds K, the
core C, and the mouthpiece 11, to form the parison P,
as shown in Fig. 10. Upon completion of injection mold-
ing, the mouthpiece 11 is integrally bonded to the
parison P.
The parison P thus prepared is then demolded
and transferred to the biaxial orientation blow mold to
blow the parison P into the bottle body P' as shown in
Fig. 11. In the blow molding process, the lower part 16
of the mouthpiece 11, which extends to the shoulder P3
near the neck P2 f the body P' as mentioned above,
undergoes orientation together with the parison P.
~ 1 66~75
The mouthpiece 11 made of high viscosity resin
is poorer in moldability than the parison P made of low
vi.scosity polyester resin, but the lower part 16 of the
mouthpiece 11 can conform to the configuration of the
shoulder P3 near the neck P2, because only a little
orientation is made at the shoulder P3 near the neck P2.
The parison P made of low viscosity saturated
polyester resin can be formed into the bottle body P'
having a relatively sharp corner, as shown in Fig. 11,
because of its good moldability.
The bottle according to this invention is
suitable for use as cosmetic containers which in many
cases have a square shape with sharp corners. In addition,
the bottle according to this invention is suitable for
use as containers for liquid cosmetics containing alcohol
at relatively high concentrations and perfumes.
The advantages of this invention may be
summarized as follows: It is possible to increase the
chemical durability and mechanical strength of the mouth
and the part e~tending from the neck to the shoulder of
the bottle which undergo no or little orientation. It
is possible to make the bottle having relatively sharp
corners because the body is made of low viscosity poly-
ester resin having good moldability. The mouthpiece is
integrally bonded to the body of the bottle as the result
of insert molding in which the mouthpiece serves as a
part of the mold. The mouthpiece and the parison can be
- -- 10 --
" "` 1 1 66~75
handled as a single object in the conventional manner
without any modification.
