Synthetic resin container

Abstract

To provide a synthetic resin container that comprises a rotation stop structure for a cap at a mouth part of a container body, and also can suppress sealability between the mouth part and cap from decreasing when heat crystallization processing is performed for hot filling.SOLUTION: The present invention relates to a synthetic resin container that comprises a container body 10 and a cap 20 plugging the mouth part 11 of the container body 10 to keep the container body 10 sealed, and at least the mouth part 11 is formed of crystalline resin material. The synthetic resin container has, on an outer wall surface of the mouth part 11, an annular projection 12 which is fitted to the cap 20 in an undercut manner, and a plurality of convex parts 13 which are provided above the annular projection and engaged with a rib 24 formed on an inner wall surface of the cap 20 to prevent the cap 20 from rotating, wherein the convex parts 13 are arrayed annularly at equal intervals over the entire periphery of the mouth part 11 leaving a gap 14 allowing the rib 24 to pass through when the cap 20 plugs the mouth part, and the mouth part 11 has, as heat-resistance region crystallized by heating, a region including at least the annular projection 12 and convex parts 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a synthetic resin container comprising a container body and a cap that is attached to the mouth of the container body by stoppering, and in particular to a synthetic resin container that can prevent the cap from rotating around the mouth of the container body after stoppering. [Background technology]

[0002] BACKGROUND ART Conventionally, containers have been widely used in which a bottle-shaped container body made of a synthetic resin material is filled with contents such as food or chemicals, and a cap is attached to the opening by a stopper (for example, Patent Document 1).

[0003] In Patent Document 1, in order to prevent the cap attached to the mouth of the container body by stoppering from rotating in a circumferential direction in a post-processing step after stoppering or due to tampering, etc., a locking protrusion is provided on the mouth of the container body, and a rib on the inner wall surface of the cap is engaged with the locking protrusion to prevent the cap from rotating. However, if the cap rotates in a circumferential direction after stoppering, the seal between the cap and the mouth of the container body will be damaged, and outside air will enter the container body, contaminating the contents and making it impossible to guarantee the set expiration date. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-1508 Summary of the Invention [Problem to be solved by the invention]

[0005] When filling a bottle-shaped container made of a synthetic resin material with a beverage, seasoning, or other such content, the content may be filled and sealed at a high temperature (75 to 93°C) for the purpose of sterilization, a process known as hot filling. If the container body is made of a resin material with a glass transition temperature lower than the hot filling temperature, such as polyethylene terephthalate resin, thermal deformation may occur, creating a gap between the mouth of the container body and the cap, potentially resulting in poor sealing. Therefore, containers used for hot filling are typically subjected to a heat treatment on the mouth to improve its heat resistance and increase its crystallinity (hereinafter referred to as "thermal crystallization treatment").

[0006] However, as in Patent Document 1, when a locking protrusion is provided at the mouth of the container body to prevent the cap from rotating, the thickness of the mouth becomes uneven, which causes the mouth to shrink and deform distortedly when thermal crystallization is performed during hot filling, resulting in a loss of roundness and a poor seal with the cap.

[0007] Therefore, the present invention aims to provide a synthetic resin container in which a cap is attached to the mouth of the container body by stoppering, which has a structure to prevent the cap from turning around at the mouth of the container body and which can suppress a decrease in the sealing ability between the mouth and the cap when a thermal crystallization process is performed during hot filling. [Means for solving the problem]

[0008] The synthetic resin container of the present invention, which has been developed to achieve the above object, comprises a container body for storing contents, a mouth portion provided in the container body for pouring out the contents through a passage leading to the inside of the container body, and a cap fitted to the mouth portion for sealingly holding the container body, wherein at least the mouth portion is formed of a crystalline resin material, The mouth portion has, on its outer wall surface, an annular protrusion that can be undercut-fitted with the cap when the cap is plugged, and a plurality of protrusions that are provided above the annular protrusion and engage with ribs formed on the inner wall surface of the cap to prevent the cap from rotating around the mouth portion, the protrusions are arranged in a ring shape at equal intervals around the entire circumference of the opening, separated by gaps that allow the rib to pass through when the cap is attached; The mouth portion is characterized in that a region including at least the annular projection and the convex portion is a heat-resistant region that is crystallized by heating.

[0009] In the synthetic resin container of the present invention, it is preferable that the protruding portion has an outward protrusion margin of 10 to 40% of the wall thickness of the mouth.

[0010] In the synthetic resin container of the present invention, the width of the convex portion along the periphery of the mouth is preferably 0.8 to 2.0% of the circumferential length of the mouth.

[0011] In the synthetic resin container of the present invention, the width of the gap along the periphery of the mouth is preferably 40 to 60% of the width of the convex portion. [Effects of the Invention]

[0012] According to the synthetic resin container of the present invention, the mouth of the container body is provided with multiple protrusions that prevent the cap from rotating in the circumferential direction, and these protrusions are arranged in a ring shape at equal intervals around the entire circumference of the mouth, so there is no bias in the thickness of the mouth, and even if the mouth of the container is heated and subjected to thermal crystallization treatment during hot filling, the mouth will not shrink or deform distortedly, and there is no risk of the sealing ability with the cap being reduced.

[0013] Furthermore, according to the present invention, by making the protrusion of the convex portion outward from the mouth portion 10 to 40% of the thickness of the mouth portion, it is possible to suppress uneven shrinkage deformation of the mouth portion during thermal crystallization treatment, and by engaging the convex portion with a rib provided on the inner wall surface of the cap, it is possible to improve the rotation torque of the cap and prevent the cap from rotating when handled during transportation or due to tampering.

[0014] Furthermore, according to the present invention, by making the width dimension of the convex portions around the mouth portion 0.8 to 2.0% of the circumference of the mouth portion, and further making the width dimension of the gaps (concave portions) between the convex portions around the mouth portion 40 to 60% of the width dimension of the convex portions, the convex portions and the gaps (concave portions) are finely repeated, which effectively prevents irregular shrinkage deformation caused by differences in the thickness of the mouth portion during thermal crystallization treatment. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B are diagrams showing one embodiment of a synthetic resin container according to the present invention, in which (a) is a cross-sectional view of the cap, and (b) is a front view showing the upper part of the container body, with the right half of the figure shown in cross section. [Figure 2] 2(a) is an enlarged end view taken along the line AA in FIG. 1(b), and FIG. 2(b) is an enlarged view of a portion of the end view in FIG. 2(a). DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows an embodiment of a synthetic resin container according to the present invention, where (a) is a cross-sectional view of the cap, and (b) is a front view showing the upper part of the container body, showing the cross-section of the right half on the right side of the figure. Fig. 2(a) is an enlarged end view taken along the line AA in Fig. 1(b), and Fig. 2(b) is an enlarged view of a portion of the end view in Fig. 2(a).

[0017] The synthetic resin container of the present invention comprises a container body 10 and a cap 20 that is attached to the mouth portion 11 of the container body 10 by plugging.

[0018] The container body 10 may have any shape as long as it has a bottom wall, a peripheral wall (body) rising from the edge of the bottom wall, and a cylindrical mouth 11 formed at the top of the peripheral wall via a shoulder. The mouth 11 has an annular protrusion 12 on its outer circumferential surface and multiple convex portions 13 above the annular protrusion 12, and the convex portions 13 are arranged in a ring shape at equal intervals around the entire circumference of the mouth 11, as shown in FIG. 2(a). Note that "above the annular protrusion 12" here means that the upper and lower ends of the convex portions 13 are located above the upper and lower ends of the annular protrusion 12, respectively. Therefore, although the present embodiment illustrates an example in which the upper end of the annular protrusion 12 and the lower end of the convex portions 13 overlap, the annular protrusion 12 and the convex portions 13 may be spaced apart in the vertical direction.

[0019] The container body 10 is made of a synthetic resin material. While the material is not particularly limited, at least the mouth portion 11 is made of a crystalline resin material such as polyethylene resin or polyethylene terephthalate resin. This allows the mouth portion 11 to be crystallized by a thermal crystallization treatment, improving its heat resistance and preventing thermal deformation of the mouth portion 11 when hot-filled with contents. For example, if the container body 10 is made of polyethylene terephthalate resin, a thermally crystallized region can be formed by heating the mouth portion 11 at approximately 150 to 200°C. The thermally crystallized region preferably covers the entire mouth portion 11, but may be limited to at least the region including the annular protrusion 12 and the protrusion 13. The thermally crystallized region has a higher degree of crystallinity than other portions, a lower light transmittance, and a higher longitudinal elastic modulus.

[0020] The cap 20 is composed of a cap body 21 and a lid body 22 connected to the cap body 21 via a hinge 26. The cap body 21 has a circular top wall 21a and a cylindrical peripheral wall 21b that hangs down from the periphery of the top wall 21a and has a downwardly opening. The inner wall surface of the peripheral wall 21b has an annular protrusion 23, and when the cap 20 is pressed from above onto the mouth 11 of the container body 10 to plug it, the annular protrusion 23 undercut-fits with the annular protrusion 12 of the mouth 11, thereby closing the mouth 11. In addition, a content ejection hole 21a1 is provided in the center of the top wall 21a.

[0021] Lid 22 has a circular top wall 22a and a cylindrical peripheral wall 22b that hangs down from the periphery of top wall 22a, with a sealing tube 22c hanging down from the underside of top wall 22a. When lid 22 is closed onto cap body 21, sealing tube 22c fits into spout hole 21a1 of cap body 21, sealing the container. Lid 22 has an operating protrusion 25 that protrudes outward from the lower end of peripheral wall 22b, and can be easily opened by pushing operating protrusion 25 up with a finger.

[0022] Furthermore, on the inner wall surface of the peripheral wall 21b of the cap body 21 of the cap 20, a plurality of ribs 24 are arranged annularly at equal intervals over the entire circumference on the upper part of the annular protrusion 23.

[0023] In this embodiment, the cap 20 is shown as an example consisting of a cap body 21 and a lid body 22, but this is not limited to this and any type of cap may be used as long as it can be attached to the mouth 11 of the container body 10 by plugging.

[0024] In the synthetic resin container of this embodiment, when the cap 20 is attached to the mouth 11 of the container body 10 by plugging, as described above, the annular convex portion 23 of the cap 20 fits undercut into the annular protrusion 12 of the mouth 11, and the multiple ribs 24 provided on the inner wall surface of the peripheral wall 22 of the cap 20 pass through (fit into) the gaps 14 located between the multiple convex portions 13 arranged in a ring shape at equal intervals on the outer wall surface of the mouth 11, thereby engaging the convex portions 13 with the ribs 24.

[0025] As a result, when the cap 20 is rotated in the circumferential direction, the ribs 24 catch on the protrusions 13, preventing the cap 20 from rotating, thereby preventing unexpected rotation of the cap 20 during handling or due to tampering. Note that in order to prevent rotation of the cap 20 due to tampering or the like, it is preferable that the rotation torque be 150 N or more.

[0026] In this embodiment, the ribs 24 are arranged at equal intervals around the entire inner wall surface of the peripheral wall 22 of the cap 20 to match the gap 14 of the mouth portion 11, but at least one rib 24 is sufficient, and the number of ribs 24 is determined appropriately depending on the size and use of the container, rotational torque, etc.

[0027] As shown in Fig. 1(b), each of the plurality of protrusions 13 has a vertically elongated elliptical shape when viewed from the front, and is provided at equal intervals as shown in Fig. 2(a). Note that the shape of the protrusions 13 is not limited to that shown in the drawing.

[0028] 2(b), the protrusions 13 are formed so that their outward protrusion margins (d) of the mouth 11 are 10 to 40%, more preferably 20 to 30%, of the thickness (c) of the mouth 11. This is because if the outward protrusion margins (d) of the protrusions 13 of the mouth 11 are less than 10% of the thickness (c) of the mouth 11, the ribs 24 provided on the inner wall surface of the peripheral wall 22 of the cap 20 will not catch tightly on the protrusions 13, making it impossible to improve the rotational torque and prevent rotation due to tampering, etc. Furthermore, if the protrusion margins (d) exceed 40%, there is a risk of non-uniform shrinkage deformation occurring when the mouth 11 is subjected to thermal crystallization.

[0029] Furthermore, by setting the width dimension (a) of the convex portion 13 around the mouth portion 11 to 0.8 to 2.0% of the circumference of the mouth portion 11, and further setting the width dimension (b) of the gaps 14 (concave portions) between the convex portions 13 around the mouth portion 11 to 40 to 60% of the width dimension of the convex portions 13, the convex portions 13 and the gaps 14 (concave portions) are finely repeated, and irregular shrinkage deformation caused by differences in the thickness of the mouth portion 11 during thermal crystallization treatment can be suppressed. [Industrial Applicability]

[0030] The synthetic resin container of the present invention can be suitably used as a container for storing contents such as cosmetics, medicines, etc., in addition to foods and drinks that are hot filled. [Explanation of symbols]

[0031] 10 Container body 11 Mouth 12 Annular protrusion 13 Convex part 14 Gap 20 Caps 21 Cap body 21a Ceiling wall 21b Surrounding wall 21a1 Outlet hole 22 Lid 22a Ceiling wall 22b Surrounding wall 22c Sealing tube 23 Annular convex part 24 Ribs 25 Operation protrusion 26 Hinge

Claims

1. A synthetic resin container comprising: a container body for storing contents; a mouth portion provided in the container body for pouring out the contents through a passage leading to the inside of the container body; and a cap fitted to the mouth portion for sealingly holding the container body, wherein at least the mouth portion is formed of a crystalline resin material; The mouth portion has, on its outer wall surface, an annular protrusion that can be undercut-fitted with the cap when the cap is plugged, and a plurality of protrusions that are provided above the annular protrusion and engage with ribs formed on the inner wall surface of the cap to prevent the cap from rotating around the mouth portion, the protrusions are arranged in a ring shape at equal intervals around the entire circumference of the opening, separated by gaps that allow the rib to pass through when the cap is attached; A synthetic resin container, characterized in that the region of the mouth, which includes at least the annular protrusion and the convex portion, is a heat-resistant region that is crystallized by heating.

2. 2. The synthetic resin container according to claim 1, wherein the protrusion has an outward protrusion margin of 10 to 40% of the wall thickness of the mouth.

3. 3. The synthetic resin container according to claim 1, wherein the width of the convex portion along the periphery of the mouth is 0.8 to 2.0% of the periphery of the mouth.

4. 4. The synthetic resin container according to claim 3, wherein the width of the gap along the periphery of the mouth is 40 to 60% of the width of the convex portion.

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