JP2001335050A - Cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cap which can effectively prevent damages of the cap caused by the environmental stress breakage without increasing the wall thickness of the cap. SOLUTION: This cap 10 bas an internal screw 14 on an inner circumferential surface thereof to be screwed in a neck part 13 of a container body 11 holding a predetermined liquid accommodated therein, and the internal screw 14 comprises two to four threads comprising two to four spiral projecting bars 14a and 14b to be screwed. The liquid accommodated in the container body is a surfactant and a chlorine-based bleaching agent for instance containing sodium hypochlorite. The screw angle θ of the projecting bars 14a and 14b to be screwed is 80-120 deg., and the screw height H is 1-15% of the thread bottom radius of the internal screw 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ESCR (environmentally mounted) mounted on a container body containing a liquid containing a surfactant.
The present invention relates to a cap having an excellent effect of ronmental stress cracking resistance.

[0002]

2. Description of the Related Art A liquid containing a surfactant such as a bleaching agent is contained in a resin bottle container, and a cap attached to the mouth and neck of the container body is removed. Use the inner solution while weighing appropriately with a cap. After use of the internal solution, the bottle container is closed again by attaching the cap again. In such a bottle container, the liquid adheres to the cap while the cap is being repeatedly removed and attached, and the internal solution is measured by the cap, and is affected by the surfactant. , The cap was liable to break due to environmental stress destruction. Further, when the internal solution is a liquid containing a surfactant and sodium hypochlorite, environmental stress destruction was more likely to occur due to the synergistic effect of these.

[0003] Damage to the cap due to environmental stress destruction is particularly at the point where stress is concentrated and applied, where the upper end of a male screw formed on the mouth and neck of the bottle container fits, that is, the female screw is It is likely to occur due to cracking at the terminal end on the cap top surface side. According to the conventional technology, the cap is thickened at such locations to reinforce the cap to prevent breakage of the cap due to environmental stress destruction. However, the amount of resin that is the material of the cap increases. At the same time, a plasticizing time and a cooling time are required in a manufacturing process by injection molding or the like, and productivity is reduced.

An object of the present invention is to provide a cap which can effectively prevent the cap from being damaged due to environmental stress destruction without increasing the thickness of the cap.

[0005]

SUMMARY OF THE INVENTION The present invention is a cap having an internal thread formed on an inner peripheral surface thereof, which is screwed to a mouth and neck of a container body in which a liquid containing a surfactant is contained. The female screw is composed of 2 to 4 helically threaded convex threads.
The above object has been achieved by providing a cap which is a 条 4 thread.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cap 10 according to a preferred embodiment of the present invention shown in FIGS. 1 to 3 has a neck and neck of a container body 12 in a bottle container 11 made of polyethylene containing, for example, a chlorine bleach as an internal solution. The unit 13 is detachably screwed and used. That is, a female screw 14 is formed on the inner peripheral surface of the cap 10, and the female screw 14 is screwed into a male screw 15 formed on the outer peripheral surface of the mouth and neck portion 13 of the container body 12, so that the cap 10 is It is attached and fixed to the mouth and neck 13 of the main body 12.

[0007] According to the cap 10 of the present embodiment, the female screw 14 formed on the inner peripheral surface is a double-threaded screw comprising two spirally-engaged convex ridges 14a and 14b. Further, each of the threaded ridges 14a, 14b constituting the female screw 14 is formed.
Has a screw angle θ of 80 to 120 ° and a screw height (height from the root of the screw to the tip of the screw) H of the female screw 1
4 to 1 to 15% of the root radius (radius at the root of the screw) R
(See FIG. 3).

[0008] The cap 10 is made of polyethylene,
Manufactured by injection molding. The cap 10 includes a circular top surface portion 16 and a peripheral wall portion 17 extending in a skirt shape from a peripheral edge of the top surface portion 16. The top surface portion 16 is a circular plate-like portion having a diameter of about 33 mm, and has an inner outer surface provided with an annular outer inner ring portion 19 and an inner inner ring portion 20 concentrically with the top surface portion 16. It is provided in double. When the cap 10 is attached and fixed to the mouth and neck portion 13 of the container body 12, the outer inner ring portion 19
Is in close contact with the distal end surface of the mouth and neck portion 13 so as to sandwich the inner plug 21, and the inner inner ring portion 20 pushes and expands the fitting ring portion 22 provided on the inner plug 21. It is closely inserted into the ring portion 22. With these, the container body 12 is kept in a sealed state, and leakage of the chlorine bleach inside is effectively prevented.

The peripheral wall portion 17 is a cylindrical portion integrally joined to the peripheral edge portion of the top surface portion 16, and has a vertical portion 23 having a length of about 26 mm and a thickness of about 3 mm, and a continuous portion below the vertical portion 23. And an enlarged taper portion 24. Vertical part 2
A female screw 14 is formed on the inner surface of the base 3 except for about 10 mm below the top 16. The outer surface of the vertical portion 23 is knurled so that a finger does not slip when the cap 10 is rotated (see FIG. 2).

According to the present embodiment, the pair of threaded ridges 14a and 14b constituting the female screw 14 are each set at the lower end of the vertical portion 23 at the position facing the radial direction of the inner peripheral surface as the starting point. The process starts and spirally extends toward the top surface portion 16 so as to be alternately overlapped with each other, and then ends with the position facing radially as the end portion.

Each of the threaded ridges 14a and 14b has a substantially trapezoidal cross section which is oriented sideways, and as shown in FIGS. 3 (a) and 3 (b), the screw angle θ at the tip thereof. Is 80-1
20 °. When the screw angle is 80 to 120 °, the dispersion of stress when the cap 10 is fastened to the mouth and neck portion 13 of the container body 12 can be efficiently achieved, which is preferable in molding. The screw height H of each of the threaded ridges 14 a and 14 b is 1 to 15% of the root radius R of the female screw 14. The screw height H is 1 to 15 of the root radius R of the female screw 14.
%, When the cap 10 is fastened to the mouth-and-neck portion 13 of the container body 12, it is possible to maintain a good engagement of the mouth-and-neck portion 13 with the male screw 15.

According to the present embodiment, as shown in FIG. 1, the cap 10 is detachably screwed to the mouth and neck portion 13 of the container body 12 in which the external thread 15 formed by the double thread is formed. Here, the male screw 15 is formed of a pair of threaded ridges 15a, 1a.
5b, these threaded ridges 15a, 15
b starts from the position on the radially opposite side of the outer peripheral surface of the mouth and neck portion 13 as a starting point, and extends spirally toward the distal end portion so as to be alternately overlapped with each other. Each ends as an end. In addition, the cap 10 has the inner plug 21 fitted into the opening at the tip of the mouth and neck portion 13, and the inner plug 21
Is screwed onto the mouth and neck 13 with the interposition of. The inner stopper 21 is a member made of a synthetic resin, and prevents a large amount of chlorine bleach from flowing out of the mouth and neck 13 at a time when using the chlorine bleach contained in the container body 12. Then, it is attached to control the outflow amount from the spout 30 to be an appropriate amount.

The cap 10 of this embodiment is also used as a measuring device, and the chlorine bleach is used after it is once transferred to the cap 10 and weighed.
The chlorine bleach adheres to the inner peripheral surface of the. Also cap 1
0 is repeatedly subjected to stress due to repeated attachment and detachment of the container body 12 to and from the mouth and neck 13. Therefore, the cap 10 is in a state where environmental stress destruction is likely to occur due to the influence of the chlorine bleach and the repetitive stress.
In particular, after the distal end of the outer inner ring portion 19 comes into close contact with the distal end surface of the mouth and neck portion 13 through the inner plug 21, the cap 10
When the screw is further tightened, stress is intensively applied to the end portion of the female screw 14 on the top surface portion 16 side, and thus a crack is easily generated in this portion.

According to the cap 10 of the present embodiment, since the female screw 14 is constituted by a double thread consisting of a pair of threaded ridges 14a and 14b, the female screw 14 to which stress is concentrated is applied. It is possible to effectively suppress the occurrence of cracks at the terminal portion on the top surface 16 side. That is, the threaded ridges 14 a and 14 b are screwed into the threaded ridges 15 a and 15 of the male screw 15.
Although it becomes a cantilever beam due to the stress from the contact point with point b and is likely to crack at its base end, the stress is dispersed by being supported at two places by a pair of threaded ridges 14a and 14b. Thus, stress can be effectively alleviated.

Therefore, according to the cap 10 of the present embodiment, it is possible to effectively prevent the cap from being damaged due to environmental stress destruction without increasing the thickness of the cap 10.

The cap of the present invention can be variously modified without being limited to the above embodiment. For example, the liquid contained in the container body does not necessarily need to be a liquid containing a surfactant and sodium hypochlorite, but may be a liquid containing at least a surfactant. Further, the female screw does not necessarily have to be a double thread, but may be a triple or four thread. Furthermore, it is not always necessary to interpose an inner plug at the upper end of the mouth and neck when screwing the cap.

[0017]

Hereinafter, the cap of the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 and Comparative Example 1 Ten caps having female screws formed of double-threaded screws having the same shape as the cap 10 of the above embodiment were prepared as samples of Example 1. The root radius of the female screw is 15 mm, the screw angle θ at the tip of each thread to be screwed is 80 °, and the screw height H is 0.8 mm.
And On the other hand, as a sample of Comparative Example 1, ten caps each having a female screw made of a single thread having the same shape as the cap 10 of the above embodiment were prepared. As in the first embodiment, the root radius of the female screw was 15 mm, the screw angle θ at the tip of each thread to be screwed was 80 °, and the screw height H was 0.8 mm. FIG. 4 is a developed view showing the double thread of Example 1 and the single thread of Comparative Example 1 along the inner peripheral surface of the cap.
(A) and (b). Each of Example 1 and Comparative Example 1
ESC is performed on 0 samples by the following opening and closing method.
The R (environmental stress fracture) effect was evaluated. Table 1 shows the test results.

[0019]

[Table 1]

[Cap ESCR Test Method by Opening / Closing Method] For each of 10 samples, weigh a kitchen highter (trade name: Kao Corporation) as a liquid containing a surfactant and sodium hypochlorite (female screw part). After that, remove the measured liquid and gently remove the drops to attach the liquid to the inside of the cap. These samples were placed on the mouth and neck of the same container body as in the above-described embodiment in which a male screw of two or one thread was formed.
The container is screwed in with a torque of kgf · cm, and these containers are stored at 50 ° C. for 24 hours (all day and night). Each container is taken out once a day, and each sample is checked for cracks in the threaded portion. The same method is repeated to store the container again at 50 ° C. for 24 hours. The ESCR time was evaluated by setting the time until cracks occurred in five of the five samples out of the ten samples as F50.

According to the test results shown in Table 1, the cap of Example 1 having the double thread according to the present invention was compared with the cap of Comparative Example 1 which was the conventional cap having the single thread. Time has risen about three times, ESCR
It turns out that the effect is remarkably improved.

[0022]

According to the cap of the present invention, it is possible to effectively prevent the cap from being damaged due to environmental stress destruction without increasing the thickness of the cap.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a state in which a cap according to an embodiment of the present invention is screwed to a mouth and neck of a container body.

FIG. 2 is a partially broken front view showing a cap according to an embodiment of the present invention.

3A is a partially enlarged cross-sectional view of a cap according to an embodiment of the present invention, and FIG. 3B is an enlarged view of a portion A in FIG.

FIG. 4A is a development view along an inner peripheral surface of a cap for explaining a single thread screw of Comparative Example 1, and FIG.
It is a development view along the inner peripheral surface of the cap explaining a line screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cap 11 Bottle container 12 Container main body 13 Neck and neck part 14 Female screw 14a, 14b Threaded convex ridge 15 Male screw 15a, 15b Threaded convex ridge 16 Top surface part 17 Peripheral wall part 21 Inner plug 23 Vertical part

Continuation of the front page (72) Inventor Mitsuo Yamanoi 2-1-3 Bunka, Sumida-ku, Tokyo F-term in the Kao Corporation Research Institute F-term (reference) 3E084 AA04 AA12 AA25 AB01 BA01 BA03 CA01 CB02 CC03 CC04 DA01 DB12 DC03 DC04 EA04 EB02 FA09 FB01 FB04 FC07 GA04 GA08 GB04 GB12 KB01 LA17

Claims (3)

[Claims] 1. A cap having a female screw formed on an inner peripheral surface thereof, the female screw being screwed to a mouth and neck of a container main body containing a liquid containing a surfactant, A cap which is a 2-4 threaded screw composed of four spiral threaded convex threads. 2. The cap according to claim 1, wherein the liquid contained in the container body is a liquid containing a surfactant and sodium hypochlorite. 3. The thread angle of the thread to be screwed is 80 to 12.
0 ° and the screw height is 1 to 15 of the root radius of the female screw.
%.