JPH10203551A - Sealed container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed container capable of forming seal excellent in stable sealing and unsealing properties by using a plastic cap having a sealing part integrally formed on an inner face of the cap, without increasing cost, and also capable of solving such problems as the blowing of contents and the bouncing of the cap at the time of opening of the container even in the case where the container is used to be filled with a carbonated beverage. SOLUTION: This sealed container comprises a bottle 1 made of plastic and a cap 6 made of plastic, and has each tightening mechanism at both of a neck of the bottle 1 and a skirt part 10 of the cap 6. The bottle 1 of plastic has, at a top end of the neck, a sealing flange 2 in a cantilever-like state in which its outer peripheral side forms a free end and its inner peripheral side forms a base portion, while the cap 6 has a ring 8 for engaging with an outer peripheral portion of the sealing flange 2. Sealing is performed by an elastic deformation of the ring 8 in its axial direction and an elastic deformation of the flange 2 in its axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed container comprising a plastic bottle and a cap, and more particularly, to a cap having a relatively large elastic deformation at a bottle mouth sealing position which can be restored under a sealing load. The present invention relates to a sealing form having a sealing performance and a stability of opening performance of the sealing device.

[0002]

2. Description of the Related Art Plastic caps using a liner on the inner surface of the cap are widely used as caps for beverage bottles because they can seal the container mouth. However, in order to reduce manufacturing costs, plastic caps with a seal part integrated on the inner surface of the cap without using a liner are used for some filling products that are not affected by pressure or heat, such as aseptic filling. And the sealing performance is inferior to the cap with liner.

It is also known to provide a sealing mechanism at the mouth of the bottle in order to improve the sealing performance. For example, Japanese Patent Application Laid-Open No. 53-95778 discloses a groove formed at the top of a glass or hard plastic bottle. It is described that by providing a ring and fixing an elastic seal portion to the ring, the sealing performance is excellent even in a crown or the like that does not use a seal liner.

Japanese Patent Application Laid-Open No. 58-216552 discloses that the top plate has elasticity, the upper end of the container opening pushes the inner packing by inserting the cap, and the cap top plate is deformed by upward deformation of the top plate. Using the resulting side pressure, the inner diameter of the seal lip is slightly larger than the outer diameter of the container so that the seal lip and the container opening are tightly engaged and the seal is maintained. The invention of a plastic cap is described.

Further, Japanese Patent Application Laid-Open No. 58-73551 discloses that a seal lip portion of a specific shape projecting obliquely inward is provided in an annular shape at a portion of the inner surface of the top plate or the inner surface of the skirt which engages with the container opening. Accordingly, a plastic cap having improved sealing performance is disclosed.

[0006]

However, in the structure in which the elastic seal portion is fixed to the top of the container, a new material must be added to the mouth of the bottle, which increases the manufacturing cost of the container.

The internal packing and the seal lip of the cap are large in size and have a structure in which engagement is performed over a considerable swiveling distance when the cap is swung and inserted into the container opening. As the cap is inserted into the container, the engagement pressure between them increases, and furthermore, the shrinkage of the caliber of the hot-filled container and the change in the rigidity of the cap material under low-temperature storage are caused by the internal packing and seal lip. There is a disadvantage that the opening torque value at the time of unsealing increases (or decreases) due to the influence of the pressure.

In addition, it has been recognized that such a cap engagement method often causes troubles such as blowing out of contents and popping out of the cap when actually used in a carbonated beverage filling container.

[0009] Therefore, a technical problem of the present invention is to use a plastic cap in which a seal portion is integrally formed on the inner surface of the cap, and to provide a seal excellent in stable sealing performance and opening performance without increasing the cost. Another object of the present invention is to provide a hermetically sealed container which can form a container and can prevent blowing out of contents and popping out of a cap at the time of opening when used for filling a carbonated beverage.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a sealed container comprising a plastic bottle and a plastic cap and having a fastening mechanism at a bottle neck and a cap skirt. (A) The plastic bottle is provided with a sealing flange at the tip of the neck, a cantilever having a free end on the outer peripheral side and a root on the inner peripheral side, and (b) a plastic cap for sealing. (C) sealing is performed by the axial elastic deformation of the ring and the axial elastic deformation of the flange. It is a feature.

In the sealed container of the present invention: The sealing flange is used at the operating temperature of the container.
And 50 to 1000 kg / mm^TwoFlexural modulus E₁
And the ring is 5 to 300 kg / mm^Two Bending of
Modulus E_TwoAnd both are in the range E₁≧ E_Two
1. have the following relationship (means d): The elastic deformation at the sealing position of the flange
Large displacement A, elastic at the seal position of the ring
When the maximum displacement of the deformation is B, the value of the ratio A / B is
2. Being in the range of 0.05 to 1 (means e); The cap can be a cap ring or bottle
Having a receiving seat capable of engaging with the flange (means f);
Is preferred.

[0012]

Since the above means (a) is employed, the sealing flange is deformed within the elastic range of the material from the outer peripheral side to the base due to the load at the time of sealing, and when the sealing load is about to decrease, the sealing load is reduced by springback. It restores the shape before deformation and suppresses a decrease in sealing load, and maintains stable sealing performance.

In addition, since the above-mentioned means (b) is employed, at the sealing position on the outer peripheral portion of the flange, the direction in which the sealing load acts and the direction of the relative displacement of the ring are the same direction. It is hardly affected by shrinkage etc., keeps a stable opening and closing plug state, and the ring at the time of sealing mainly has a relationship between the sealing load and deformation amount due to bending elastic deformation, and the sealing load can gradually decrease with opening. Therefore, there is a problem in the sealing method by the side pressure with the container mouth part, such as blowing out the contents at the time of opening in the carbonated beverage container, and instability of the opening torque value under low temperature storage such as radial sealing. The effect of the axisymmetric effect on the state is eliminated.

Further, in the sealed container according to the present invention, the bottle of the means (A) and the cap of the means (B) are sealed by their axial elastic deformation as in the means (C). With such a combination, reliable sealing can be performed in response to a wide range of tapping pressure (plugging torque), and the opening torque is not excessive, the opening operation is easy, and the autogenous pressure is further increased. Can effectively solve the problem of blowing out the contents and flying the cap. In addition, in this specification, an axial direction means the axial direction of a cap and a bottle.

[0015] In a preferred sealed container of the present invention, the sealing flange portion of the bottle and the ring portion of the cap are provided with:
By having the bending elastic modulus as in the above means (d), the flange portion bears a large load and the ring portion bears a small load, thereby enabling pressure-resistant continuous sealing and leakage due to pressure fluctuation. It will be effectively prevented. This action can be more reliably achieved by controlling the displacement of the flange and the ring within the range of the means (e).

Furthermore, by forming a receiving seat for the above-mentioned means on the cap, excessive deformation of the ring having low bending elasticity can be caused even when the sealed container receives an impact such as dropping. To prevent the ring from breaking,
It is possible to maintain the sealing performance even after receiving an impact.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The plastic bottle of the present invention
It is obtained by plastic blow molding or plastic stretch blow molding, and consists of a body, a closed bottom connected to the bottom of the body, a shoulder connected to the top of the body, and a mouth or neck connected to the shoulder in the same manner as a normal bottle. At the tip of the neck, that is, at the mouth, a sealing flange is provided in the form of a cantilever having a free end on the outer peripheral side and a root on the inner peripheral side.

In FIG. 1 showing an example of a cross-sectional structure of the plastic bottle mouth 1 of the present invention, the inner side of the bottle is on the right side.
The outer bottle side is shown as the left side. At the tip of the neck,
The sealing flange 2 is provided in the form of a cantilever having a free end on the outer peripheral side and a root 3 on the inner peripheral side, and the outer peripheral portion 4 at the sealing position with the cap is elastically deformed at the sealing load with the material of the root 3 at the sealing load. The flange is formed to have a relatively large relative displacement within the range.
An external thread 5 for fastening with a cap is formed on the outer peripheral surface of the neck.

The cap used in the present invention is formed by injection molding or compression molding of plastic, and has a top plate (top surface) and a skirt hanging from the periphery thereof. And a ring engaged with the outer peripheral portion of the sealing flange.

FIG. 2 shows an example of the cross-sectional structure of the cap. In FIG. 2, the cap 6 has a top plate 7 and a skirt 9.
And a receiving seat 11 for suppressing the ring to a suitable amount of deformation.

In the sectional view of FIG. 3 and the explanatory view of FIG. 4 showing the relative positional relationship between the bottle and the cap in a sealed state, according to the present invention, the female screw 13 of the cap is connected to the male screw 5 of the bottle mouth. By engaging the cap 6, turning the cap 6 and fastening it to the container opening 1, the sealing position of the container opening flange outer peripheral portion 4 first comes into contact with the ring tip 10, and the ring 8 undergoes bending deformation. The ring tip gradually increases the pressing force B against the flange outer peripheral portion 4. The flange outer peripheral portion 4 is relatively displaced in the same axial direction as the reaction force A of the flange but in the opposite direction due to elastic deformation at the base 3 in accordance with the sealing load with the ring 8. Further, the ring tip portion 10 further increases the pressing force B to the outer peripheral portion of the flange by contact with the receiving seat 11, but the bending deformation of the ring and the amount of plastic deformation of the material are suppressed. The sealing portion of the flange receives a force greater than the pressure due to the bending of the ring due to the pressing action from the seat 11 of the cap, and the sealing is completed in a state of being relatively moved in the direction of the flange reaction force in the same manner.

As described above, excellent sealing performance can be obtained by the sealing effect due to the elastic deformation of the flange portion and the bending deformation of the ring. In addition, the seal position between the outer peripheral portion of the flange and the vicinity of the ring tip is the same direction (axial direction) in which the direction in which the seal load is applied and the relative displacement direction of each seal position. As the sealing load is reduced, the pressure is gradually released, so that the problems of the blowout of the internal pressure-filled product and the cap flying are eliminated.

Further, in the case of a hot-filled product, a slight shrinkage of the opening of the container is caused at the container opening due to the heat effect for sterilization. In this case, the sealing pressure increases (or weakens) and the sealing load varies, and the plastic material used for the cap has high rigidity in a low temperature range. There is a problem that the plug torque value increases and the plug opening property becomes unstable compared to a container in a storage state at about room temperature or higher. On the other hand, in the present invention, since the sealing method does not use the lateral pressure, the shrinkage of the container diameter does not significantly affect the opening performance, and the effect of the hardness of the material at the storage temperature is also reduced. Since the direction of the seal load and the direction of movement of the seal portion due to the opening are the same, the advantage of not being greatly affected is achieved.

Since the flange shape according to the present invention has an elastic deformation effect, it is desirable that the sealing surface with the cap be substantially horizontal. As shown in FIG. 6, when the angle of inclination with respect to the horizontal plane from the center from the center of the inclination angle with respect to a horizontal plane lower flange surface for theta ₁ and sealing of the sealing flange upper surface and the _{θ 2, -10 ° ≦ θ 1} ≦ 30
° and 0 ° ≦ θ ₂ ≦ 30 ° are preferable in order to enable proper elastic deformation of the flange.

The ring shape of the cap according to the present invention has a shape protruding from the top plate 7, a skirt 9 and a corner 1.
Regardless of the shape protruding from 2, the ring is desirably subjected to bending deformation due to pressure from the outer peripheral portion of the flange during sealing, and a structure that does not undergo excessive plastic deformation of the material under an appropriate sealing load state. For this purpose, the ring protruding from the top 7 may prevent excessive deformation by contacting the seat 11 with an appropriate amount of bending deformation. Further, as shown in the figure, the ring 8 has a structure in which the thickness gradually decreases at least from the middle of the length of the ring toward the tip of the ring, which enables sealing in a wide sealing load range and This is preferable from the viewpoint of increasing the seal break angle.

The mechanical properties of the material used for the container mouth and the cap may be 50 to 50 around the flange of the container mouth under the temperature at which the container filled with the contents is used.
1000 kg / mm has ² flexural modulus E _1, flexural modulus in the range of 5 to 300 kg / mm ² in the ring portion of the cap E ₂
It is preferable that the relationship of E ₁ ≧ E _{2 is} satisfied in order to obtain good sealing performance and unsealing performance in a sealed state.

Further, when the maximum value of the relative displacement after sealing at the outer peripheral portion sealing position of the flange and the ring is B, and the maximum value of the relative displacement after sealing of the ring is B, It is desirable that the value of the ratio A / B be in the range of 0.05 to 1.0 in terms of the balance between the deformation of the flange and the ring.

According to the present invention, the outer diameter of the container portion is preferably Φ = 8 to 100 mm in the outer diameter of the flange portion. If the diameter is smaller than this range, the influence of the axial symmetry of the flange portion is large, and the necessary seal is required. Since the amount of elastic deformation of the flange is smaller than the load, the effect on the sealing performance is reduced. Further, when the diameter is larger than that, when the cap is tightened by the screw method, the difference in the sealing load in the circumferential direction becomes large, and there is a possibility that the sufficient sealing effect in the present invention cannot be exhibited.

The plastic bottle of the present invention can be formed from various plastics. However, since the mouth of the container after molding has a suitable sealing performance and opening performance, the bending elasticity, which is a mechanical property of the material, is required. Rate E ₁ 50 to 1000 kg / mm
² must be satisfied. Also, in the case where the degree of crystallinity of the container mouth portion which is an unstretched portion is increased in blow molding or the like and used for hot filling, it is preferable that the flange portion is used within the mechanical property range of this material.

The plastic constituting the container is, for example, high-density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene, or ethylene, propylene, 1-butene, 4-methyl-1-pentene, etc. α-olefin random or block copolymers, polyolefins such as cyclic olefin copolymers such as ethylene-norbornene copolymer; polystyrene, acrylonitrile-styrene copolymer, ABS, α
-Styrene resins such as methylstyrene / styrene copolymer; chlorine-containing polymers such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer; acrylic resins such as polymethyl acrylate and polymethyl methacrylate Nylon 6, Nylon 6-6, Nylon 6-1
Polyamide resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or copolymerized polyesters thereof; polycarbonates; polyarylates; polyphenylene oxides or mixtures thereof. Any resin may be used.
Of course, by using a biodegradable resin, an environmentally friendly resin molded product can be provided.

As for the cap material used in the present invention,
For example, olefin resins such as low density, medium density or high density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymer, propylene-ethylene copolymer, propylene-butene 1 copolymer, etc .; acrylonitrile-styrene -Made of any resin such as butadiene (ABS) resin; impact-resistant styrene resin; acrylic resin; and nylon-based resin, the material has a bending elastic modulus of 5 as mechanical properties in terms of sealing performance and opening performance. To 3
It is preferable to select a resin that satisfies the range of 00 kg / mm ² and has good moldability at the ring portion.

Of course, the plastic bottle and the plastic cap used in the present invention must be combined so as to satisfy the above-mentioned conditions. That is, the first is the relationship between the plastic materials defined by the means (2), and the second is the relationship between the deformation of the bottle flange and the cap ring defined by the means (e).

The radial dimension of the bottle flange (FIG. 1,
Although a) differs depending on the outer diameter of the mouth, it is generally 0.1 mm.
Suitably, it is in the range of 5 to 8 mm, while the radial dimension from the outer peripheral end of the flange to the base (FIG. 1, b) is in the range of 20 to 90% of the radial dimension (a) of the flange. Is preferred. On the other hand, the axially protruding dimension (FIG. 2, c) from the base to the tip of the cap ring is suitably in the range of 0.5 to 15 mm, and the average thickness of the ring (FIG. 2, d) is 0.3. It is preferably in the range of 5 to 5 mm. In addition, the inclination angle of the ring with respect to the horizontal plane (FIG. 2,
e) should be in the range of 20 to 160 °.

When the ring 8 is formed on the inner surface side of the top plate portion 7 of the cap, as shown in FIG. 2, it is smooth to provide the ring 8 at an angle so that the outer diameter of the ring gradually increases in the radially outward direction. The receiving seat 11 is suitable for performing a proper sealing, but can be engaged with the distal end of the ring 8 at the time of sealing.
It is preferable that the action portion is provided on the outer peripheral side of the base of the ring 8 and higher than the distal end portion 10 of the ring 8. The height gap between the ring tip 10 and the working part of the seat 11 is such as to allow the aforementioned deformation of the ring. The ring 8 and the seat 1
A groove 17 is provided between the ring 1 and the ring 1 so that the ring can be easily deformed and the ring can be smoothly engaged with the receiving seat.

It should be understood that many changes can be made in the sealed container of the present invention without departing from the spirit of the present invention. For example, as shown in FIG. 7, the above-mentioned silling 8 and receiving seat (first receiving seat) are provided on the inner surface of the cap.
11 and a second receiving seat 11 b can be provided on the inner peripheral side of the ring 8. This second seat 11b
Can be engaged with the inner peripheral side of the bottle flange, and when the sealed container receives a drop impact or the like, prevents the impact from being applied to the ring, and acts to maintain the seal.

In the embodiment shown in FIG. 8, the ring 8 of the cap has a root at a portion near the corner 12 of the skirt 7, and its tip extends inward in a radial direction and inclined downward. ing. On the other hand, on the inner surface side of the top plate 7,
An inner ring 14 is formed to regulate the position so that the engagement between the bottle flange and the ring 8 occurs at the outer periphery of the flange.

In the above embodiment, only the part of the cap necessary for sealing with the bottle is shown. However, this cap has any pill fur proof function (tamper evidence function) known per se. It is natural that they may do so. The pill fur proof feature may consist, for example, of a ring-shaped band connected to the lower end of the skirt via a breakable bridge, which band non-rotatably engages the bottle neck.

[0038]

EXAMPLE A PET bottle preform having a flange formed on the outer periphery of the mouth as shown in FIG. 1 was injection-molded and bottle-molded by a blow molding machine. A corresponding polypropylene integrated plastic cap having a seal portion as shown in FIG. 2 was molded by a CCM molding machine. The following performance evaluation tests were performed on the combinations of these bottles and caps.

1. Test method 1) Opening torque measurement Bottle adjustment: a. 87 ° C hot water, fill 23ml head space. b. Sealing with a tightening torque of 14 kg · cm. c. After lying down for 30 seconds immediately after capping, 60 ° C for 15 minutes,
Shower cooling at 30 ° C for 15 minutes. The cap and bottle molded articles of the present invention were prepared by the above method, and stored at room temperature, 5 ° C., and 40 ° C., n = 4, for a total of 12 bottles, and the opening torque after 1 day, 1 week, and 2 weeks. (1st
Torque) was measured with a torque meter. 2) Ventilation test According to the method of 1), the opening angle at which the seal was broken at the time of opening was measured. 3) Heat cycle test (n = 5, control 4)
Book) The cap and bottle of the present invention prepared by the method 1)
After storing at 0 ° C. for 1 week, 5 ° C. for 1 week, 40 ° C. for 1 week, and 5 ° C. for 1 week, the reduced pressure value was measured. For the control, the reduced pressure value was measured after storing at room temperature for 4 weeks.

2. Results The results of this example according to the above-described evaluation test method are shown in Tables 1 to 3 below in comparison with the plastic caps (comparative examples) of the sealing method using lateral pressure shown in FIG.

1) Opening torque measurement (1st torque / unit [゜])

[Table 1] As compared with the comparative example, the embodiment has less fluctuation of the opening torque due to the storage temperature, and there is no increase in the torque especially at a low temperature.

2) Vent test (seal break angle / unit [゜])

[Table 2] Compared to conventional caps, the seal break angle is very small, and there is less worry about cap flying.

3) Heat cycle test (n = 5, control 4)

[Table 3] The reduced pressure value was constant for both the test sample and the control, and there was no decrease in the sealing ability.

[0044]

According to the present invention, a sealing flange is provided at the tip of the bottle neck in a cantilever state in which the outer peripheral side is a free end and the inner peripheral side is a root. By providing a ring that engages with the outer peripheral portion of the flange, and sealing is performed by the elastic deformation of the ring and the elastic deformation of the flange, it is possible to obtain good sealing performance. Further, in a plastic cap without a liner, the sealing portion according to the present invention has the same sealing load and opening movement direction, so that the opening torque value at the time of opening is smaller than that of the cap of the sealing method by lateral pressure. Instability is eliminated, and even when used for sealing an internal pressure container, there is no danger of blowing out the contents or flying the cap.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a container mouth according to the present invention.

FIG. 2 is a sectional view showing an example of a plastic cap according to the present invention.

FIG. 3 is a cross-sectional view showing a fastening state between the container mouth part of FIG. 1 and the cap of FIG. 2;

FIG. 4 is a sectional view of a cap of a comparative example.

FIG. 5 is an explanatory view showing deformation of a flange of a container mouth and a ring of a cap.

FIG. 6 is a sectional view showing another example of the container mouth according to the present invention.

FIG. 7 is a sectional view showing another example of the shape of the plastic cap according to the present invention.

FIG. 8 is a sectional view showing still another example of the shape of the plastic cap according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container mouth part 2 Flange 3 Root 4 Flange peripheral part 5 Male screw 6 Cap 7 Top plate part 8 Ring 9 Skirt 10 Ring tip part 11 Receiving seat 12 Corner part 13 Female screw 14 Inner ring 15 Seal lip 16 Internal packing

Claims (4)

[Claims] 1. A container comprising a plastic bottle and a plastic cap and having a fastening mechanism at a bottle neck and a cap skirt, wherein the plastic bottle has a sealing flange at a tip of the neck,
The cap is provided in a cantilever state in which the outer peripheral side is a free end and the inner peripheral side is a root, and the cap includes a ring that engages with an outer peripheral portion of the sealing flange. Sealing is performed by elastic deformation of the flange in the axial direction. 2. The sealing flange portion has a flexural modulus E ₁ of 50 to 1000 kg / mm ² at the operating temperature of the container, and the ring has a bending modulus of 5 to 300 kg / m 2.
m ² It has a flexural modulus E _2, and, both E ₁ ≧ E ₂
The sealed container according to claim 1, wherein the sealed container has the following relationship. 3. When the maximum displacement of elastic deformation at the sealing position of the flange is A and the maximum displacement of elastic deformation at the sealing position of the ring is B, the ratio A /
3. The sealed container according to claim 1, wherein the value of B is in the range of 0.05 to 1. 4. The sealed container according to claim 1, wherein the cap has a receiving seat capable of engaging with a ring of the cap or a flange of the bottle.