Plastic container lid

Abstract

To provide a novel container lid made of synthetic resin that, even if a content liquid intrudes into a space 68 defined between an upper surface of a closure wall 8 and a lower surface of a top face wall 44 across the closure wall 8 in a state a top lid 6 is desirably operated unsealed relatively to a body 4 and then the top lid 6 is fitted again onto the body 4, the content liquid intruded into the space is allowed to sufficiently easily return into a container.SOLUTION: A container lid made of synthetic resin includes a prevention piece 34 or 34' that, when the top lid 6 is fitted again onto the body 4, abuts against a lower surface of a removal region 16 or an upper surface of a remaining region 18 and prevents the removal region 16 from closing the closure wall 8.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a synthetic resin container lid that includes a main body and a top lid, and when the top lid is subjected to a required opening operation relative to the main body, a breakable thin-walled line formed in the closing wall of the main body is broken, and a removal area of ​​the closing wall of the main body is removed from the closing wall together with the top lid. [Background technology]

[0002] Patent Document 1 listed below discloses a synthetic resin container lid for liquid seasonings such as soy sauce, edible oil, and dressing, which includes a main body and a top lid, the main body having a closing wall which is partitioned into a removal area surrounded by a breakable thin-wall line and a remaining area outside the breakable thin-wall line, the top lid having a top wall and a skirt wall hanging down from the periphery of the top wall, the removal area of ​​the closing wall and the top wall being connected by a connecting means, and when the top lid is subjected to the required opening operation relative to the main body, the breakable thin-wall line is broken and the removal area of ​​the closing wall is removed from the closing wall together with the top lid. In this container lid, the main body has a cylindrical mounting wall depending from the periphery of the closing wall, and the outer peripheral surface of the skirt wall is connected to the outer peripheral surface of the mounting wall of the main body via hinge means, so that the top lid can freely pivot between a closed position which covers the closing wall of the main body and an open position which exposes the closing wall of the main body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-289389 A Summary of the Invention [Problem to be solved by the invention]

[0004] Thus, the container lid disclosed in the above Patent Document 1 may have the following problems. When the top lid is reattached to the main body after the required opening operation of the top lid is performed on the main body, the outer peripheral edge of the lower surface of the removal area abuts against the inner peripheral edge of the upper surface of the remaining area, but the blocking wall is not completely blocked by such abutment, and some gaps are present in the blocking wall. Therefore, if the container is turned sideways or vigorously shaken vertically for a long period of time with the top lid reattached to the main body, the liquid content passes through the gap provided in the blocking wall (i.e., goes beyond the blocking wall) and enters the space defined between the upper surface of the blocking wall and the lower surface of the top wall. Even if the container is then re-uprighted, since the gap provided in the blocking wall is not large enough, it is difficult for all of the liquid content that has entered the space to pass through the gap in the blocking wall and return to the container, and some of the liquid content remains on the upper surface of the blocking wall. If the user reopens the top lid from the main body while the liquid content remains on the upper surface of the closing wall, there is a risk that the remaining liquid content will splash out and soil the user's clothes or surroundings.

[0005] The present invention has been made in consideration of the above-mentioned facts, and its main technical object is to provide a new and improved synthetic resin container lid which, when the top lid is reattached to the main body after the required opening operation has been performed on the main body, allows the content liquid which has entered the space defined between the upper surface of the closing wall and the lower surface of the top wall to easily return to the container even if the content liquid has passed over the closing wall and entered the space. [Means for solving the problem]

[0006] After careful consideration, the inventor discovered that the above-mentioned main technical objective can be achieved by forming a blocking piece on the main body that elastically deforms the removal area and prevents the removal area from blocking the blocking wall when the top cover is reattached to the main body.

[0007] That is, according to the present invention, a synthetic resin container lid that solves the above-mentioned main technical problem includes a main body and a top lid, The body has a closing wall, the closing wall being partitioned into a removal region surrounded by a breakable thin-wall line and a remaining region outside the breakable thin-wall line; The top cover has a top wall and a skirt wall depending from a peripheral edge of the top wall, a removable region of the closing wall and the top wall are connected by a connecting means, and when the top lid is subjected to a required opening operation relative to the main body, the breakable thin-wall line is broken, and the removable region of the closing wall is removed from the closing wall together with the top lid; A synthetic resin container lid is provided, characterized in that the main body is formed with a preventing piece that elastically deforms the removal area to prevent the removal area from blocking the blocking wall when the top lid is reattached to the main body.

[0008] Preferably, before the breakable thin-wall line is broken, the blocking piece rises upward from the upper surface of the remaining area and then enters the removal area in a plan view, and when the top cover is reattached to the main body, the upper surface of the blocking piece and the lower surface of the removal area come into contact with each other. Before the breakable thin-wall line is broken, the blocking piece hangs downward from the lower surface of the removal area and then enters the remaining area in a plan view, and when the top cover is reattached to the main body, the lower surface of the blocking piece and the upper surface of the remaining area come into contact with each other. The blocking piece may be composed of an upper blocking piece located above the blocking wall and entering the removal area in a plan view before the breakable thin-wall line is broken, and a lower blocking piece that hangs down from the lower surface of the removal area and then enters the remaining area in a plan view, and when the top cover is reattached to the main body, the upper surface of the upper blocking piece and the lower surface of the lower blocking piece may come into contact with each other. Preferably, a plurality of blocking pieces are provided at intervals along the breakable thin-wall line. The connecting means is preferably a connecting rod extending upward from the upper surface of the removal area, and the extending end of the connecting rod is preferably welded to the inner surface of the top wall. Preferably, the body has a cylindrical mounting wall depending from the periphery of the closing wall, the outer periphery of the skirt wall is connected to the outer periphery of the mounting wall of the body via hinge means, and the top cover is pivotable between a closed position covering the closing wall of the body and an open position exposing the closing wall of the body. In this case, before the breakable thin-wall line is broken, the closing wall is preferably inclined downward from the side where the hinge means is present to the side where the hinge means is not present. The connecting means is preferably disposed on the side where the hinge means is not present, and the blocking piece is preferably disposed on the side where the hinge means is present. Advantageously, the removal area is wider on the side where the hinge means is present than on the side where the hinge means is not present. Effect of the Invention

[0009] In the synthetic resin container lid constructed according to the present invention, a blocking piece is formed on the main body for preventing the removal area from closing the blocking wall by elastically deforming the removal area when the top lid is reattached to the main body, so that a gap of sufficient size is reliably formed in the blocking wall when the top lid is reattached to the main body, and even if the liquid contents pass through the gap and enter the space defined between the upper surface of the blocking wall and the lower surface of the top wall, the liquid contents that have entered the space can easily return through the gap to the inside of the container. As a result, even if the container is turned sideways or vigorously shaken up and down for a long period of time with the top lid reattached to the main body, causing the liquid contents to enter the space, the liquid contents are prevented from remaining on the upper surface of the blocking wall, and therefore the liquid contents are prevented from scattering even if the top lid is reattached to the main body and then opened again. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view of a synthetic resin container lid constructed according to the present invention, showing a state before the main body and the top lid are connected and when the top lid is in an open position relative to the main body. [Diagram 2] 2 is a bottom view of the synthetic resin container lid in the state shown in FIG. 1. [Diagram 3] 2 is a cross-sectional view taken along line AA of the synthetic resin container lid shown in FIG. 1. [Figure 4] 4 is a cross-sectional view of the synthetic resin container lid shown in FIG. 1 in a state where the top lid is in a closed position relative to the main body and the removed area of ​​the closing wall of the main body and the top wall of the top lid are connected. [Diagram 5] 5 is a cross-sectional view showing the state immediately after the top cover starts to rotate relative to the main body from the state shown in FIG. 4. [Figure 6] 5 is a cross-sectional view of the top cover when it is rotated relative to the main body from the state shown in FIG. 4 to an open position. [Figure 7] 13 is a cross-sectional view of the top cover reattached to the main body. FIG. [Figure 8] FIG. 11 is a cross-sectional view showing a modified example of a synthetic resin container lid constructed according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a synthetic resin container lid according to an embodiment of the present invention; FIG.

[0012] 1 to 3, a synthetic resin container lid generally designated by the numeral 2 is formed by injection molding from a suitable synthetic resin such as polyethylene or polypropylene, and includes a main body 4 and a top lid 6. In the illustrated embodiment, the main body 4 and the top lid 6 are connected via hinge means 7, as described below.

[0013] The main body 4 has a blocking wall 8 and a cylindrical mounting wall 10 that hangs down from the periphery of the blocking wall 8. The blocking wall 8 is circular in plan view, i.e., in FIG. 1, and a substantially cylindrical pouring guide wall 12 that extends upward is formed in the radially intermediate portion of the upper surface of the blocking wall 8. The upper end of the pouring guide wall 12 is curved radially outward, and the upper end position of the pouring guide wall 12 is set so that a required angle region located on the right side in FIG. 3 is lower than other angle regions. As can be understood by referring to FIG. 3, the blocking wall 8 is substantially horizontal on the radially outer side of the pouring guide wall 12, but on the radially inner side of the pouring guide wall 12, it inclines downward relatively gently from the right side of the figure where the hinge means 7 exists to the left side where the hinge means 7 does not exist, and then inclines upward relatively sharply.

[0014] The blocking wall 8 is divided into a removal area 16 surrounded by the breakable thin-wall line 14 and a remaining area 18 outside the breakable thin-wall line 14. The removal area 16 is located inside the pouring guide wall 12. In Figs. 1 to 3, the removal area 16 is wider on the right side where the hinge means 7 is present than on the left side where the hinge means 7 is not present, and has a shape that tapers from the right side to the left side passing through the center of the blocking wall 8. The tapered end of the removal area 16, i.e., the left end, is located close to the lower end of the blocking wall 8 and slightly to the right of it, and the removal area 16 is generally inclined downward from the right side to the left side. As can be clearly understood by referring to Fig. 3, the breakable thin-wall line 14 is composed of a so-called score formed by locally reducing the thickness of the blocking wall 8. The removal area 16 is formed with a central protruding pillar 20 that protrudes upward. The central protruding column 20 is located at the center of the blocking wall 8, and is a residue of a flow path formed to allow the molten synthetic resin material injected from the molding machine to flow as required when the container lid 2 is molded by injection molding. The upper end surface of the central protruding column 20 is a so-called gate portion, which is closed. The removal area 16 is also provided with a connecting column 22 extending upward. The connecting column 22 is located at the tapered end on the opposite side of the removal area 16 from the side where the hinge means 7 is provided, that is, on the left side in Figs. 1 to 3. Referring to Fig. 2 together with Fig. 1, the cross section of the connecting column 22 is approximately V-shaped, with the top 24 in a plan view being located slightly to the right of the tapered end of the removal area 16, and the outer periphery extending along the inner periphery of the breakable thin-wall line 14. As shown in Fig. 3, the connecting column 22 extends upward beyond the central protruding column 20 when viewed in the vertical direction, and the extending end portion of the connecting column 22, designated by the number 26, is slightly thinner than the other portions of the connecting column 22. A cylindrical engaged wall 28 is formed on the upper surface of the remaining region 18, i.e., the outer circumferential edge of the blocking wall 8, and an annular engaged ridge 30 is formed at the upper end of the outer circumferential surface of the engaged wall 28. A cylindrical sealing wall 32 that hangs down downward is formed on the lower surface of the outer circumferential edge of the blocking wall 8, and the outer circumferential surface of the sealing wall 32 faces the inner circumferential surface of the mounting wall 10 with a radial gap therebetween.

[0015] The blocking wall 8 is formed with a blocking piece 34 which rises upward from the upper surface of the remaining region 18 and then enters the removal region 16 in a plan view. A plurality of blocking pieces 34 (two in the illustrated embodiment) are provided at intervals along the breakable thin-wall line 12, and the base end of the blocking piece 34 is located on the side where the hinge means 7 is present at the inner peripheral edge of the remaining region 18, that is, on the right side in Figs. 1 to 3, in other words, on the side where the removal region 16 is wider. The blocking piece 34 is elastically deformable with its base end as an axis. Further reference will be made to the blocking piece 34 later.

[0016] A locking means 36 is provided on the lower end of the inner circumferential surface of the mounting wall 10. In the illustrated embodiment, the locking means 36 is composed of a plurality of arcuate ridges extending in the circumferential direction at intervals in the circumferential direction. If desired, the locking means can be composed of annular ridges extending continuously in the circumferential direction. An arcuate notch 38 is formed in the upper end of the outer circumferential surface of the mounting wall 10 at a portion diametrically opposite to the hinge means 7. The mounting wall 10 is further provided with a known separation mechanism including a bottomed annular groove 40 with an open upper surface and an axial slit 42, which allows the container lid 2 to be separated from the mouth and neck of a container to be described later and discarded by performing a required operation after the container lid 2 is attached to the mouth and neck of the container to be described later and used. For details of such a separation mechanism, please refer to, for example, Japanese Patent No. 6326472, which was filed by the applicant of the present application prior to the present application and has already been granted a patent.

[0017] 1 to 3, the top cover 6 has a circular top wall 44 and a cylindrical skirt wall 46 hanging down from the periphery of the top wall 44, and the lower end of the outer circumferential surface of the skirt wall 46 is connected to the upper end of the outer circumferential surface of the mounting wall 10 of the main body 4 via hinge means 7, and the top cover 6 can be freely rotated between a closed position (the state shown in Figs. 4 and 7) where it covers the blocking wall 8 of the main body 4 and an open position (the state shown in Figs. 3 and 6) where it exposes the blocking wall 8 of the main body 4. A receiving recess 50 having a cross-sectional shape corresponding to the cross-sectional shape of the extending end 26 of the connecting post 22 extending upward from the removed region 16 of the blocking wall 8 of the main body 4 is formed at a required position on the lower surface of the top wall 44, and the receiving recess 50 receives the extending end 26 of the connecting post 22 when the top cover 6 is rotated to the closed position. An inner cylindrical wall 52 and an outer cylindrical wall 54 are also formed on the lower surface of the top wall 44, and two annular shallow grooves 56 are formed between the inner cylindrical wall 52 and the outer cylindrical wall 54. A flange 58 protruding radially outward is provided on the portion of the outer peripheral surface lower end of the skirt wall 46 opposite in the diametric direction to the hinge means 7, and a finger can be hooked on the flange 58 when the top cover 6 is turned open or closed. Furthermore, a thin-walled arc-shaped protruding piece 60 protruding downward is formed on the lower surface of the skirt wall 46 opposite in the diametric direction to the hinge means 7. An annular locking ridge 62 is provided on the lower end of the inner peripheral surface of the skirt wall 46, and an annular abutting ridge 64 is also provided on the inner peripheral surface of the skirt wall 46, located above the annular locking ridge 62.

[0018] 1 to 3, that is, the container lid 2 is molded with the top lid 6 in the open position relative to the main body 4, and after molding, the top lid 6 is rotated from the open position to the closed position. As can be clearly understood by referring to Fig. 4, when the top lid 6 is positioned at the closed position, the annular locking rib 62 of the top lid 6 is locked to the outer circumferential surface or the lower surface of the locked rib 30 of the main body 4, the annular abutment rib 64 of the top lid 6 is abutted against the upper end of the locked wall 28 of the main body 4, the outer circumferential surface of the inner cylindrical wall 52 of the top lid 6 is brought into close contact with the inner circumferential surface of the pouring guide wall 12 of the main body 4, and the extending end 26 of the connecting post 22 of the main body 4 is received in the receiving recess 50 of the top lid 6. Then, with the top cover 6 in the closed position, i.e., with the extending end 26 of the connecting post 22 received in the receiving recess 50, a suitable welding means (not shown), such as an ultrasonic welder, is applied from the upper surface of the top wall 44 to weld the top wall 44 and the connecting post 22, thereby connecting the removed area 16 of the blocking wall 8 to the top wall 44. If desired, the top wall 44 and the connecting post 22 can be connected by a suitable connecting means, such as a suitable heat welding machine or adhesive, instead of the ultrasonic welder.

[0019] 4 shows, by a two-dot chain line, a container lid 2 constructed according to the present invention as well as a neck of a container to which the container lid 2 is applied. The neck of the container 100, which can be formed from a suitable synthetic resin or glass, has a cylindrical shape with an open top, and a lockable ridge 102 is formed on the upper end of its outer circumferential surface. A support ring 104 (used when transporting the container) is also formed on the outer circumferential surface of the neck of the container, located below the lockable ridge 102.

[0020] When the container lid 2 is attached to the mouth and neck portion 100 to seal it after the contents have been placed in the container, the container lid 2, more specifically, the container lid 2 with the top lid 6 in the closed position relative to the main body 4 and the removed area 16 of the blocking wall 8 of the main body 4 connected to the top wall 44 of the top lid 6, is fitted over the mouth and neck portion 100 and forced downward, causing the mounting wall 10 of the main body 4 to elastically deform so that the locking means 36 formed on the inner surface of the mounting wall 10 is locked below the locked protrusion 102 of the mouth and neck portion 100.

[0021] When the contents of the container are consumed, a finger is placed on the underside of the flange 58 of the top cover 6, and an upward force is applied to the flange 58 about the hinge means 7 as a pivot. This force is then transmitted to the closing wall 8 via the top wall 44 and the connecting column 22, and attempts to displace the removal area 16 of the closing wall 8 together with the top cover 6 upward about the hinge means 7 as a pivot, thereby generating a shear stress in the breakable thin-walled line 14. This shear stress causes the breakable thin-walled line 14 to break gradually from one side opposite the hinge means 7 to the other side in the diametrical direction, as shown in FIG. 5. After the breakable thin-walled line 14 is completely broken, the removal area 16 is pivoted in the opening direction together with the top cover 6 via the connecting column 22, and thus a discharge opening is created in the closing wall 8. In the initial stage when the removal area 16 is pivoted together with the top cover 6 in the opening direction, the upper surface of the outer peripheral edge of the removal area 16 abuts against the lower surface of the extended end of the blocking piece 34, and the outer peripheral edge of the removal area 16 elastically overcomes the blocking piece 34, and then the top cover 6 is pivoted together with the removal area 16 to the open position shown in Fig. 6. Thereafter, by appropriately tilting the container, the contents of the container are discharged through the discharge opening.

[0022] After the discharge of the contents is completed, the top cover 6 is rotated around the hinge means 7 as the rotation center in the closing direction, i.e., in the direction to cover the blocking wall 8, and is reattached to the main body 4. In the illustrated embodiment, the blocking wall 8 is formed with a blocking piece 34 that rises upward from the upper surface of the remaining area 18 and then enters the removal area 16 in a plan view. As a result, when the top cover 6 is reattached to the main body 4, as can be clearly understood by referring to FIG. 7, the upper surface of the blocking piece 34 abuts against the outer peripheral edge of the lower surface of the removal area 16, so that the removal area 16 is elastically deformed, more specifically, the side where the hinge means 7 is present is elastically curved upward from the side where the hinge means 7 is not present, so that the removal area 16 is prevented from blocking the blocking wall 8, and a gap 66 is formed in the blocking wall 8. Therefore, the liquid content contained in the container can pass through the gap 66 (i.e., go beyond the closing wall 8) and move easily between the inside of the container and a space 68 defined between the upper surface of the closing wall 8 and the lower surface of the top wall 44. Since the outer peripheral surface of the inner cylindrical wall 52 of the top cover 6 is in close contact with the inner peripheral surface of the pouring guide wall 12 of the main body 4, the liquid content that has entered the space 68 does not leak out of the space 68.

[0023] 8 shows a modified synthetic resin container lid constructed according to the present invention. In this modified example, before the breakable thin-wall line 14 is broken, the blocking piece 34' hangs down from the lower surface of the removal area 16 and then enters the remaining area 18 in a plan view. Although not shown, when the top cover 6 is rotated in the opening direction relative to the main body 4 to consume the contents of the container, the upper surface of the extended end of the blocking piece 34' abuts against the lower surface of the inner peripheral edge of the remaining area 18 after the breakable thin-wall line 14 is broken, and the blocking piece 34' elastically overcomes the inner peripheral edge of the remaining area 18. When the discharge of the contents is completed and the top cover 6 is reattached to the main body 4, the lower surface of the blocking piece 34' abuts against the inner peripheral edge of the upper surface of the removal area 16, preventing the removal area 16 from blocking the blocking wall 8. Although not shown in the figure, the blocking piece can be composed of an upper blocking piece that is located above the blocking wall 8 (before the breakable thin-wall line 14 is broken) and enters the removal area 16 in a planar view, and a lower blocking piece that hangs downward from the underside of the removal area 16 and then enters the remaining area 18 in a planar view, so that when the top cover 6 is reattached to the main body 4, the upper surface of the upper blocking piece and the lower surface of the lower blocking piece abut each other.

[0024] That is, in the synthetic resin container lid constructed according to the present invention, the blocking piece 34 or 34' is formed in the body 4 to elastically deform the removal area 16 and prevent the removal area 16 from blocking the blocking wall 8 when the top cover 6 is reattached to the body 4, so that a sufficiently large gap 66 is reliably formed in the blocking wall 8 when the top cover 6 is reattached to the body 4, so that even if the liquid content passes through the gap 66 and enters the space 68 defined between the upper surface of the blocking wall 8 and the lower surface of the top wall 44, the liquid content that has entered the space 68 can easily return to the container through the gap 66. As a result, even if the liquid content enters the space 68 by the container being turned sideways or vigorously shaken up and down for a long period of time with the top cover 6 reattached to the body 4, the liquid content is prevented from remaining on the upper surface of the blocking wall 8, and therefore, even if the top cover 6 is reattached to the body 4 and then opened again, the liquid content is prevented from scattering.

[0025] The synthetic resin container lid constructed according to the present invention has been described in detail above with reference to the attached drawings, but the present invention is not limited to the above-mentioned embodiment, and appropriate modifications and changes are possible within the scope of the present invention. For example, in the illustrated embodiment, the blocking pieces 34 and 34' extend from the upper or lower surface of the blocking wall 8, but the blocking pieces may extend radially inward from the inner peripheral surface of the pouring guide wall 12 instead of the blocking wall 8. The number and positions of the blocking pieces 34 and 34' may be changed as appropriate. In the illustrated embodiment, the connecting means is constituted by the connecting pillars 22 extending upward from the removal area 16 of the blocking wall 8, but the connecting pillars may be hung downward from the lower surface of the top wall 44 to connect to the removal area 16 of the blocking wall 8 (welded to the upper surface of the removal area 16), or may be connected by extending from both the upper surface of the removal area 16 of the blocking wall 8 and the lower surface of the top wall 44 in a direction approaching each other. Furthermore, the removal area 16 of the blocking wall 8 and the top wall 44 can be connected by suitable engagement means such as a flap piece as shown in Japanese Patent No. 5901198, which was previously filed and already patented by the applicant of the present application, instead of by welding. Furthermore, the main body 4 and the top cover 6 do not necessarily need to be connected via the hinge means 7, and the main body 4 and the top cover 6 may be screwed together by male and female threads provided on each other. In other words, when the main body 4 and the top cover 6 are screwed together, the required opening operation of the top cover 6 relative to the main body 4 is performed by rotating the top cover 6 relative to the main body 4. The synthetic resin container cover constructed according to the present invention may also be applied to the mouth of a spout shown in Japanese Patent Publication No. 2000-326972, and when applied to the mouth of a spout, the main body 4 does not have the mounting wall 10. [Explanation of symbols]

[0026] 2: Plastic container lid 4: Main unit 6:Top lid 7: Hinge means 8: Obstruction wall 14: Breakable thin-walled line 16:Removal area 18: Residual area 22: Connecting column (connecting means) 34, 34´: Blocking piece 44: Top wall 46: Skirt Wall

Claims

1. The container includes a main body and a top cover. The body has a closing wall, the closing wall being partitioned into a removal region surrounded by a breakable thin-wall line and a remaining region outside the breakable thin-wall line; The top cover has a top wall and a skirt wall depending from a peripheral edge of the top wall, a removable region of the closing wall and the top wall are connected by a connecting means, and when the top lid is subjected to a required opening operation relative to the main body, the breakable thin-wall line is broken, and the removable region of the closing wall is removed from the closing wall together with the top lid; A synthetic resin container lid characterized in that the main body is formed with a preventing piece that elastically deforms the removal area to prevent the removal area from blocking the blocking wall when the top lid is reattached to the main body.

2. A synthetic resin container lid as described in claim 1, wherein, before the breakable thin-wall line is broken, the preventing piece rises upward from the upper surface of the remaining area and then enters the removal area in a planar view, and when the top lid is reattached to the main body, the upper surface of the preventing piece abuts against the lower surface of the removal area.

3. A synthetic resin container lid as described in claim 1, wherein before the breakable thin-wall line is broken, the preventing piece hangs downward from the underside of the removal area and then enters the remaining area in a planar view, and when the top lid is reattached to the main body, the underside of the preventing piece abuts against the upper surface of the remaining area.

4. The synthetic resin container lid of claim 1, wherein the preventing piece is composed of an upper preventing piece that is located above the blocking wall and enters the removal area in a planar view before the breakable thin-wall line is broken, and a lower preventing piece that hangs downward from the lower surface of the removal area and then enters the remaining area in a planar view, and when the top lid is reattached to the main body, the upper surface of the upper preventing piece abuts against the lower surface of the lower preventing piece.

5. 5. The synthetic resin container lid according to claim 1, wherein a plurality of said preventing pieces are provided at intervals along said breakable thin-wall line.

6. 6. The synthetic resin container lid according to claim 1, wherein the connecting means is a connecting pole extending upward from the upper surface of the removal area, the extending end of the connecting pole being welded to the inner surface of the top wall.

7. 7. A synthetic resin container lid as claimed in any one of claims 1 to 6, wherein the main body has a cylindrical mounting wall depending from the periphery of the closing wall, the outer peripheral surface of the skirt wall is connected to the outer peripheral surface of the mounting wall of the main body via hinge means, and the top lid is freely rotatable between a closed position covering the closing wall of the main body and an open position exposing the closing wall of the main body.

8. 8. The synthetic resin container lid according to claim 7, wherein, before the breakable thin-wall line is broken, the closing wall is inclined downward from the side where the hinge means is present to the side where the hinge means is not present.

9. 9. The synthetic resin container lid according to claim 7, wherein said connecting means is disposed on a side where said hinge means is not present, and said preventing piece is disposed on a side where said hinge means is present.

10. 10. The synthetic resin container lid according to claim 7, wherein the removed area is wider on a side where the hinge means is present than on a side where the hinge means is not present.

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