JPH0655420B2 - Blow molding container manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a blow-molded container, in particular, a container main body, a metered-quantity container including a cup-shaped measuring section and a cap integrally provided above the container body. is there.

[Prior art]

Conventionally, many liquid quantitative containers are plastic molded products,
An inner stopper is fitted to the neck, which is the boundary between the bottle container body and the measuring unit, and a pipe is attached to this inner stopper from the lower part.The container body is pressed to suck the liquid to be quantitatively measured from the inside of the container body. increase. The liquid coming upward from the slit provided in the inner stopper is of a system in which the container body is depressurized to depressurize the inside of the container to reversely flow the liquid and obtain a fixed amount of liquid in the upper portion of the inner stopper.

[Problems to be solved by the invention]

In the conventional product by direct blow molding in which the fixed amount part is integrated, the outer diameter of the neck is constant because it is regulated by the blow mold, but the inner diameter of the neck that fits with the inner plug greatly changes depending on the molding weight. In addition, since there is a possibility of variations in each shot, the stopper pressure of the inner stopper greatly varies, and the upper and lower positions of the inner stopper become unstable during constant pressure stoppering on the filling line. Further, since the inner surface of the fixed quantity portion cannot be regulated, the volume of the fixed quantity portion varies due to the above-mentioned reason and combined action.

In connection with the above, when the inner plug is loosely fitted, it may come loose and be lifted up, which causes a great problem in the accuracy of the quantitative determination or the function as the quantitative container.

Therefore, in order to solve the above problem, the applicant proposed a container in which only the container body is blow-molded by using a preform in which the container body and the measuring unit are integrally injection-molded, instead of the direct blow method. However, when molding such a container, as shown in FIG. 4, the measuring portion (b) of the preform (a) is
Is fixed to the upper mold (c), the lower mold (d) is closed, the bottom of the preform (a) is pushed down by the stretching rod (e) to perform longitudinal stretching, and then blow air is blown. It is designed to be blown to mold the container body. In this case, when blow air is blown, the blow core (f) is fitted so as to be in close contact with the inner wall of the measuring section (b) and then blown, but the tip end (g) of the blow core (f) is The neck (h) of the preform (a) that is in a softened state because it has reached only the middle of the measuring section (b).
Blow air passes at a high speed on the inner surface (where the inner plug is inserted) to deform the inner wall of the neck (h), resulting in variations in inner diameter.

[Means for solving problems]

The present invention has been conceived in order to solve the above-mentioned problems of the prior art, and the blow air at the time of blow molding does not hit the inner wall of the preform or container required to have dimensional accuracy, and the dimension of the inner wall. In the method of manufacturing a container, which comprises a container body and a cup-shaped measuring portion integrally provided above the opening of the container body, a part corresponding to the container body is blow-molded. It is characterized in that the inner surface in the vicinity of the boundary between the container body and the measuring section is blow-molded while being shielded so as not to hit blow air.

[Work]

Hereinafter, a molding method according to the present invention in which the inner diameters of the quantifying portion and the neck portion of the bottle body portion can be precisely formed will be described with reference to the drawings.

The present invention is effective for the biaxial stretch molding method, whether it is a one-stage hot parison method or a two-stage cold parison method. As shown in FIG. 1, the preform (1) is temperature-controlled in advance to a temperature suitable for stretch-blowing, and the lip cavity (2) holds the fixed amount part (3) of the preform (1), It is transferred to the stretch blow process. Blow Core (4)
Contact the upper end of the fixed quantity part (3) and the inner surface of the mouth (5), and
It is set so that the high-pressure blow air blown from the gap between (6) and the blow core (4) does not leak.

As described above, the function of the blow core (4) is to seal the upper end surface of the preform (1) so that the high-pressure blow air does not leak in the stretching blow process, but in the present invention, Furthermore, by making the tip of the blow core longer than the inner diameter of the neck to a position below the inner diameter of the neck so that the impact of high-pressure blown air does not directly hit the inner diameter of the neck, high pressure air during blowing is blown onto the inner diameter of the neck. Instead, the inner diameter of the neck of the container after stretch-blow is formed with strict accuracy.

〔Example〕

Embodiments of the present invention will be described more specifically below with reference to the drawings.

Referring to FIG. 1, the preform (1) held in the lip cavity (2) is narrowed by the blow cavity (7) and the upper bottom mold (8), and then the blow core (4) descends, Seal the top edge of the preform (1). Next to press down the bottom of the stretch rod (6) preform (1), longitudinally stretched to the substantially simultaneous pressure from the gap 10kg / cm ² ~40kg / cm ² after slight time blow core (4) and the stretching rod (6) The bottle body is formed by blow molding the preform (1) below the portion narrowed by the air blown by the lip cavity (2).

At this time, since the tip portion (9) of the blow core (4) is located at approximately the same position as the inner diameter of the neck, preferably about 3 mm below the inner diameter of the neck, high-pressure air that instantaneously rises is blown onto the inner diameter of the neck. Absent. Therefore, the dimensional accuracy of the inner diameter (D) of the neck portion shown in FIG. 2 formed after the stretch blow molding is stable, and the variation in the dimension is small even if there is a slight difference in the blow timing or the temperature of the neck portion of the preform.

FIG. 3 is an explanatory view showing the constitution of the liquid quantitative container according to the present invention. A is a bottle body, B is an inner stopper and a tube pipe, and C is a cap. FIG. 5 is an assembled sectional view.

[Comparative example]

As shown in FIG. 4, in the conventional stretch blow molding, the tip portion (g) of the blow core (f) is located slightly below the seal portion of the upper end surface of the preform (a), but above the inner diameter of the neck portion. Since it is positioned, the high pressure air ejected from the gap between the blow core (f) and the stretching rod (e) is directly blown onto the inner diameter of the neck. Therefore, the dimensional accuracy of the inner diameter D of the neck portion shown in FIG. 2 formed after the stretching blow is not stable, and the variations due to changes in the pressure of the stretching blow air, the blow timing, and the preform temperature are large. Therefore, when the inner plug is attached, the variation in the tapping force becomes large, and when the inner diameter of the neck becomes large, the fitting force with the inner plug is significantly weakened, and when the product is used as a product, the inner plug rises and is extremely serious. May lose its function as a metered container due to the inner plug coming off.

The table below summarizes the relationship between the bottle neck inner diameter (D) and the inner stopper capping force in the present example and the comparative example.

[Relationship between inner diameter of bottle neck and stoppering force]

[Effects of the Invention] In the method of the present invention, since blow air during blow molding is blocked by the tip of the blow core, the inner surface of the preform or the part corresponding to the neck of the parison is not exposed to the blow air. , There is no variation in the neck inner diameter of the molded container. Therefore, it is possible to accurately manufacture a container (a fixed-quantity container or the like) in which it is necessary to plug the inner plug or the like on the neck portion, and there is an excellent effect that there is no variation in the fitting force of the inner plug.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing the molding process of the present invention, FIG. 2 is a cross-sectional explanatory view showing the state when the molding is completed, and FIG. 3 shows an example of the constitution of the container manufactured by the present invention. FIG. 4 is a perspective view showing a conventional technique. (1) …… Preform, (2) …… Lip cavity (3) …… Measuring part, (4) …… Blow core (5) …… Mouth, (6) …… Stretching rod (7) …… Blow cavity , (8) …… Top bottom type (9) …… Tip

Claims (2)

[Claims] 1. A method of manufacturing a container comprising a container body and a cup-shaped measuring portion integrally provided above the opening of the container body, wherein the portion corresponding to the container body is blow-molded with the container body. A method for producing a blow-molded container, characterized in that the blow-molded container is shielded so as not to hit blow air on the inner surface in the vicinity of the boundary with the part and blow-molded. 2. A blow core is blown with a blow core, the lower end of which extends to the vicinity of the boundary between the container body and the measuring section, is inserted into the measuring section during blow molding of the container body. The method for producing a blow-molded container according to item 1.