JP3796594B2 - Molding method of synthetic resin casing - Google Patents

Description

[0001]
[Industrial application fields]
In the present invention, an inner layer forming a deformable inner bag is laminated and formed in an outer layer forming a fixed outer shell so that the outer shape can be peeled off, and the external liquid can be discharged to the content liquid storage unit without causing a change in appearance. The present invention relates to a method of molding a synthetic resin blow-molded casing that enables the content liquid to be poured out without intrusion.
[0002]
[Prior art]
In a blow molded housing made of synthetic resin, which is formed by detachably stacking an inner layer that forms a deformable inner bag in an outer layer that forms a fixed outer shell, deformation due to a decrease in the inner volume of the inner layer, that is, collapse In order to prevent the deformation from becoming indefinite, the outer layer and the inner layer are fixed to each other by bonding or the like at least at the mouth tube portion and the bottom portion of the outer layer and the inner layer (for example, JP-A-4-339759). No. publication).
[0003]
Further, in this type of laminated case, in the case of a case having a pump cap, the outer layer and the inner layer in the mouth tube portion are fixed by positioning the upper end of the inner layer on the upper end surface of the outer layer. This is achieved by sandwiching the upper end portion of the inner layer located on the end surface between the packing in the cap and the upper end surface of the outer layer.
[0004]
Then, by widening the clamping width of the inner layer upper end portion between the packing in the cap and the outer layer upper end surface, it is assumed that the clamping strength is strengthened and the inner layer is fixed in the mouth tube portion. A technique described in Japanese Patent No. 143080/1990 has been proposed.
[0005]
That is, the synthetic resin case described in the publication is curved from the inside to the outside at the upper end of the blow tube body in which the outer layer forming the outer shell and the inner layer forming the inner bag are detachably laminated. An inverted reversing flange is integrated so that the upper end of the reversing flange that forms the upper end surface of the mouth is formed by the upper end of the inner layer, and the reversing flange is cut from the neck burr that is integrally blow-molded into the housing. It consists of the remaining part.
[0006]
[Problems to be solved by the invention]
In the synthetic resin casing described in the above-mentioned JP-A-8-143080, the reverse flange at the upper end of the mouth tube part is integrally formed by blow molding, so that it is not in contact with the blow mold during molding. The upper surface of the reversing flange formed by the inner surface of a certain inner layer does not necessarily have sufficient smoothness, and therefore there is a problem that the sealing performance between the upper surface of the reversing flange and the lower surface of the packing in the cap may not be sufficient. there were.
[0007]
Therefore, the present invention was devised to solve the above-described problems in the prior art, and it is a technical problem to provide sufficient smoothness to the upper surface of the reversing flange that becomes the packing round of the casing, and thus the cap. It aims at improving the sealing performance between the housing and the upper end surface of the housing mouth tube portion.
[0008]
[Means for Solving the Problems]
The means of the present invention for solving the above technical problem is:
The present invention relates to a method of blow molding a casing from a synthetic resin outer layer that forms a fixed outer shell and a flexible synthetic resin inner layer that is peelably laminated on the outer layer to form an inner bag. ,
A blow head with a stepped lower surface that is a smooth pressing surface with a horizontal circumference is provided in the upper end opening of the parison, and the pressing surface is provided in the shape of an inner collar at the upper end of the mold surface portion for forming the tube portion of the blow molding die. The flange portion is pushed to a predetermined position facing from above, and the upper end of the cylindrical mouth tube portion to which the cap is screwed and assembled is bent and reversed from the inside to the outside. Integrally forming a neck burr having a connecting flange with an outer diameter sufficiently larger than the diameter;
This neck part burr is cut and removed by leaving the inner part of the connecting flange as an inverted flange in the mouth tube part after completion of the blow molding process of the housing ,
It is in.
[0009]
The blow head has an air supply hole penetrating in the center, an outer diameter that is substantially the same as the inner diameter of the parison, and an inclined guide surface that is reduced in diameter downward at the lower end of the outer peripheral surface. It is preferable to form a large-diameter cylindrical portion that is expanded through a horizontal circumferential smooth pressing surface at the upper end of the small-diameter cylindrical portion.
[0010]
[Action]
The reversing flange attached to the upper end of the mouth tube portion of the housing is formed by bending the upper end portion of the mouth tube portion inwardly and then reversing outwardly. Is the upper end of the inner layer.
[0011]
And the upper surface of this inversion flange has sufficient smoothness by the press by the press surface of the blow head at the time of shaping | molding.
[0012]
Since the upper surface of the reversing flange is the upper end surface of the mouth tube portion, that is, the portion that forms the packing round, when the cap is screwed and assembled to the mouth tube portion, the packing attached to the cap is tight. As a result, the upper end of the inner layer is firmly clamped and fixed between the cap and the outer layer, and the sufficient smoothness ensures the sealing performance with the packing.
[0013]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a half longitudinal view of a housing 1 and a cap 8 main body in a state where a pump cap 8 is screwed and assembled to the housing 1 according to the present invention. The housing 1 is made of a high-density polyethylene resin. The outer layer 2 and the nylon inner layer 3 are blow molded from a parison obtained by extrusion molding into a laminated cylindrical shape by coextrusion molding means, and a cap 8 is screwed onto the outer peripheral surface of the cylindrical mouth tube portion 4 Screws for assembling are engraved.
[0014]
As shown in FIG. 2, the upper end of the mouth tube portion 4 has a smooth upper surface in a state where the outer peripheral groove 6 is formed immediately below by reversing the upper end portion of the mouth tube portion 4 from the inside to the outside. And a ring-shaped reversing flange 5 having an outer diameter equal to that of the mouth tube portion 4 is integrally provided.
[0015]
FIGS. 3 to 5 show the main part of an embodiment of the molding method of the present invention. First, as shown in FIG. 7 is press-molded by the blow head 11.
[0016]
That is, the blow head 11 has an air supply hole 16 penetrating through a central portion thereof, and is horizontally disposed at an upper end of a small diameter cylindrical portion 12 having an outer diameter that is substantially the same as or slightly larger than the inner diameter of the parison 20. A large-diameter cylindrical portion 14 having a diameter sufficiently larger than that of the mouth tube portion 4 is formed through the circumferential smooth pressing surface 13, and is formed at the lower end portion of the outer peripheral surface of the small-diameter cylindrical portion 12. Is provided with an inclined guide surface 15 that is reduced in diameter downward.
[0017]
Therefore, the blow head 11 from above is inserted into the upper end opening of the parison 20 set in the blow molding die 10 provided with the narrow inner flange portion 10a at the upper end of the mold surface portion for forming the mouth tube portion 4. When the small-diameter cylindrical portion 12 at the tip is pushed down, the upper end portion of the parison 20 is pushed and expanded by the pressing surface 13 of the blow head 11 and the neck portion burr 7 is formed.
[0018]
Then, the blow head 11 stops at a predetermined position where the pressing surface 13 of the blow head 11 presses the upper surface of the flange portion 10a of the blow molding die 10 with the neck portion burr 7 interposed therebetween. by blowing air from the pores 16, a parison 20 portion that becomes the lower than the flange portion 10a, is blown into the bottle 1.
[0019]
The neck burr 7 formed integrally with the housing 1 is bent from the upper end of the mouth tube portion 4 of the housing 1 in a bent shape inwardly, then rises upward, and the connecting flange 7a is curved outward and reversed. This connecting flange 7a has an outer diameter sufficiently larger than the outer diameter of the mouth tube portion 4, and its upper surface has sufficient smoothness due to the pressing of the pressing surface 13 of the blow head 11. It has become a thing.
[0020]
The neck burr 7 formed integrally with the housing 1 is moved up and down at a cut position K at an outer diameter position equal to the outer diameter of the mouth tube portion 4 of the connecting flange 7a after the blow molding process of the housing 1 is completed. By cutting, the housing 1 is excised (see FIG. 4), but the inner portion of the connecting flange 7a remaining in the state of being connected to the upper end of the mouth tube portion 4 on the housing 1 side is the inverted flange as it is. 5 (see FIG. 5).
[0021]
The cutting process of the connecting flange 7a of the neck burr 7 is that the connecting flange 7a has an outer diameter larger than that of the mouth tube part 4, and that the outer peripheral groove 6 is formed directly below the connecting flange 7a. In the state in which the receiving plate is assembled to the outer peripheral groove 6, it is achieved with a cylindrical blade having a diameter equal to the outer diameter of the mouth tube portion 4 from above, thereby achieving safer, surely and accurately more easily. be able to.
[0022]
The reversing flange 5 is formed by reversing the upper end portion of the mouth tube portion 4 from the inside to the outside, so that the upper end portion of the inner layer 3 is located on the upper surface thereof. In a state where the cap 8 is screwed and assembled to the mouth tube portion 4, the upper end portion of the inner layer 3 is firmly sandwiched and fixed between the packing 9 of the cap 8 and the upper end portion of the outer layer 2, and the inner layer 3 in the mouth tube portion 4. As a result, a firm seal between the upper surface of the reversing flange 5 and the lower surface of the packing 9 is achieved by the sufficient smoothness of the upper surface of the inner layer 3 (see FIGS. 1 and 2). 2).
[0023]
When the upper end portion of the inner layer 3 is sandwiched between the cap 8 and the upper end portion of the outer layer 2, the outer peripheral groove 6 formed immediately below the reversing flange 5 functions to impart elasticity to the reversing flange 5. The immovable pinching is made stronger and more stable.
[0024]
【The invention's effect】
Since the present invention has the above-described configuration, the following effects can be obtained.
The upper surface of the reversing flange, which is the packing round of the housing, is given sufficient smoothness by pressing with the pressing surface of the blow head during molding, which can greatly improve the sealing performance between the cap packing. it can.
[Brief description of the drawings]
FIG. 1 is a right half longitudinal sectional view showing an embodiment of a housing according to the present invention in a state where a cap is assembled.
FIG. 2 is an enlarged vertical sectional view of a main part of the embodiment shown in FIG.
FIG. 3 is a partially enlarged view of a neck burr molding state showing an embodiment of the molding method of the present invention.
4 is a partially enlarged view of the embodiment shown in FIG.
FIG. 5 is a partially enlarged view of the embodiment shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Housing 2; Outer layer 3; Inner layer 4; Mouth part 5; Inversion flange 6; Peripheral groove 7; Neck part burr 7a; Connecting flange 8; Cap 9; Packing 10; Blow mold 10a; Head 12; Small-diameter cylindrical portion 13; Pressing surface 14; Large-diameter cylindrical portion 15; Inclined guide surface 16; Air supply hole 20; Parison K;

Claims (2)

An outer layer (2) made of a synthetic resin that forms a fixed outer shell, and a flexible synthetic resin inner layer (3) that is peelably laminated on the outer layer (2) to form an inner bag ( 1) in blow molding, horizontal circumferential smooth pressing surface a stepped lower surface and the blow head (11) (13), the top opening of the parison (20), said pressing surface (13), mouth tube portion of the blow mold (10) (4) is I pushed from above the flange portion provided on the inner flange-like on the upper end of the mold surface portion (10a) to a predetermined position facing the cap (8) A connecting flange having an outer diameter that is sufficiently larger than the outer diameter of the mouth tube portion (4) at the upper end of the cylindrical mouth tube portion (4) to be screwed together. A neck part burr (7) having (7a) is integrally formed, and the neck part burr (7) is formed on the inner part of the connecting flange (7a) after the blow molding process of the casing (1) is completed. The mouth tube part (4) as a reversing flange (5) Method of molding a synthetic resin bottle body cleaved off is left. The blow head (11) has an air supply hole (16) penetrating through the center, has an outer diameter that is substantially the same as the inner diameter of the parison (20), and contracts downward at the lower end of the outer peripheral surface. A large-diameter cylindrical portion (14) expanded in diameter via a horizontal circumferential smooth pressing surface (13) was formed at the upper end of a small-diameter cylindrical portion (12) provided with a diameter inclined guide surface (15). The method for forming a synthetic resin casing according to claim 1.

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