JP6229313B2 - Insert parts for blow molding - Google Patents

Description

  The present invention relates to an insert part for blow molding that is inserted at the time of blow molding.

  When manufacturing a tank 3 having an inlet as shown in FIG. 5, in order to ensure particularly high accuracy, a portion of the inlet 1 is provided around a cylindrical portion 5a having an opening 5o and the cylindrical portion 5a. The insert part 5 provided with the flange portion 5b is manufactured in advance by injection molding or the like, blow molding is performed in a state where the insert part 5 is placed in a blow molding die, and the opening 7o is formed by drilling after mold release. As a result, a blow molded product in which the insert part 5 is fused to the blow molded product main body 7 may be manufactured (see, for example, Patent Document 1).

JP 2003-236920 A

  Water or gasoline is accommodated in the tank 3, but depending on the blow molding conditions, the fusion between the insert part 5 and the blow molded product body 7 may be insufficient. A slight gap is formed between the opening of the insert part and the opening of the blow molded product body that is formed in accordance with the opening, and the liquid in the contents oozes out by the capillary reduction through this boundary gap. I found out.

  This invention is made | formed in view of such a situation, and provides the insert component for blow molding which can suppress the oozing of the liquid from the interface of an insert component and a blow molded product main body.

  According to the present invention, there is provided a blow molding insert component comprising a cylindrical portion having an opening and a flange portion provided around the cylindrical portion, and being fused to a blow molded product body by blow molding, An insert part for blow molding is provided, which includes an easily melting portion that substantially surrounds the opening and is more easily melted than the flange portion on a surface of the flange portion that is fused to the blow molded product body.

  As a result of studying to prevent the liquid from oozing out of the contents, the inventor has arranged the easy melting part so as to surround the cylindrical part of the insert part, and the insert part easily melts in the easy melting part. As a result, it was found that the insert part was reliably fused to the blow molded article body at this portion, the liquid flow due to capillary action was stopped, and the liquid oozing was suppressed, and the present invention was completed.

Hereinafter, various embodiments of the present invention will be exemplified. The following embodiments can be combined with each other.
Preferably, the easily meltable part is constituted by a thin protrusion.
Preferably, the thin protrusion has a thickness of 1 mm or less and a height of 0.5 mm or more.
Preferably, the thin protrusion has a ring shape surrounding the opening.
Preferably, the flange portion is provided with a tapered surface at a peripheral edge, the thickness of which decreases in the diameter increasing direction.
Preferably, the tapered surface is provided on both surfaces of the flange portion.

(A)-(b) shows the insert component 5 of one Embodiment of this invention, (b) is a bottom view, (a) is AA sectional drawing in (b). It is sectional drawing corresponding to Fig.1 (a) which shows the manufacturing process of the blow molded product using the insert component 5 of FIG. It is a figure corresponding to Drawing 1 (a) showing a blow-molded article obtained by a manufacturing process shown in Drawing 2. It is a figure corresponding to Drawing 1 (b) which shows another example of composition of easily melting part 5d. It is a figure corresponding to FIG. 3 which shows the structure of the blow molded product using the conventional insert components.

  Hereinafter, embodiments of the present invention will be described. Various characteristic items shown in the following embodiments can be combined with each other. The invention is established independently for each feature.

  As shown in FIGS. 1 and 3, the insert part 5 includes a cylindrical part 5a having an opening 5o and a flange part 5b provided around the cylindrical part 5a, and is fused to the blow molded product body 7 by blow molding. It is an insert part for blow molding to be worn. A surface 5c of the flange portion 5b to be fused to the blow molded product body 7 is provided with an easily melting portion 5d that substantially surrounds the opening 5o and is more easily melted than the flange portion 5b.

  The insert part 5 is a part manufactured in advance by injection molding or the like. Although the insert part 5 is entirely a resin molded product in one example, the insert part 5 can be fused to the blow molded product body 7 as long as at least the flange portion 5b and the easily meltable portion 5d are formed of resin. The other portions may be formed of a material other than resin (eg, metal).

  The easily meltable portion 5d is a portion that is melted by the heat of the parison 11 during the blow molding shown in FIG. 2 to reliably fuse the insert part 5 and the blow molded product body 7 together. The easily meltable part 5d may be a part that is more easily melted than the flange part 5b, and the specific configuration thereof is not particularly limited, and a surface 5c to be fused to the blow molded product body 7 as shown in FIG. The surface 5c may be provided with a portion made of a material having a melting point lower than that of the flange portion 5b. In any case, the easily meltable part 5d is melted by contact with the melted parison 11, and the fusion property between the insert part 5 and the blow molded article body 7 is improved. The easily meltable portion 5d may be largely deformed by melting so as not to remain in the shape before blow molding, and only the surface of the easily meltable portion 5d is melted and the shape is substantially maintained while maintaining the shape. The main body 7 may be fused.

  In the case where the easily meltable portion 5d is formed of thin projections, the thickness D shown in FIG. 1 is, for example, 2 mm or less, and preferably 1 mm or less. Moreover, the height H shown in FIG. 1 is 0.3 mm or more, for example, and 0.5 mm or more is preferable. This is because if the thickness D is too large or the height H is too small, the easily meltable part 5d may not be sufficiently melted when contacting the parison 11. The lower limit of the wall thickness D is not particularly limited, but if it is too thin, the easily meltable part 5d is likely to be damaged. Therefore, the wall thickness D is preferably equal to or greater than 0.1 mm, and more preferably equal to or greater than 0.3 mm. Further, the upper limit of the height H is not particularly limited, but if it is too high, the blow molded product main body 7 is penetrated, and therefore the height H is preferably 3 mm or less, and more preferably 2 mm or less. From another viewpoint, the height H is preferably equal to or less than the thickness of the blow molded article body 7, and more preferably equal to or less than 2/3 of the thickness.

  Further, the easily melting portion 5d substantially surrounds the opening 5o, and “substantially surrounding the opening 5o” means one ring-shaped easily melting portion as shown in FIG. This includes not only the case where 5d completely surrounds the opening 5o, but also the case where a plurality of easily meltable portions 5d are arranged in a ring shape around the opening 5o as shown in FIG. This is because even in the latter case, the meltable portion 5d is melted to form a ring-shaped fused portion, thereby preventing the liquid from oozing out.

  Moreover, the flange part 5b is provided with the taper surface (C surface cut shape) 5e which becomes thin toward the diameter-expanding direction in the periphery 5f. The tapered surfaces 5e are provided on both surfaces of the flange portion 5b. With such a configuration, the thickness at the periphery of the flange portion 5b becomes very thin, and the flange portion 5b is easily melted by that much, and the fusion property between the insert part 5 and the blow molded product body 7 is improved. improves.

Next, a method of manufacturing a blow molded product using the insert part 5 will be described with reference to FIG.
First, as shown in FIG. 2A, the insert part 5 is set at one predetermined position of the divided molds 13a and 13b. In the conventional insert component 5, it was essential to preheat the insert component 5 in order to enhance the fusion property with the blow molded product body 7. However, in this embodiment, the insert component 5 includes the easily meltable portion 5 d. The insert part 5 can be placed in the mold without remaining heat. In addition, in order to further improve the fusion property, the insert part 5 can be preheated.

  Next, as shown in FIG. 2 (a), the parison 11 in a molten state is disposed between the divided molds 13a and 13b, and the divided molds 13a and 13b are closed as shown in FIG. 2 (b). By blowing air into the mold in this state, the parison 11 is expanded in the mold to form the blow molded product body 7 having a shape along the inner surface shape of the mold. At this time, the easy melting part 5d of the insert part 5 is melted by the heat of the parison 11, and the insert part 5 and the blow molded product body 7 are reliably fused.

  Next, the obtained blow molded product is taken out from the mold, and an opening 7o is formed in the blow molded product body 7 so as to communicate with the opening 5o of the insert part 5 as shown in FIGS. Complete drilling and complete blow molding.

  In the blow-molded product thus obtained, as shown in FIG. 3, the insert on the outside of the blow-molded product from the boundary surface X between the opening 5o of the insert component 5 and the opening 7o of the blow-molded product body 7 is performed. Since the insert part 5 and the blow-molded product body 7 are securely fused at the easy melting part 5d between the boundary surface Y of the part 5 and the blow-molded product body 7, the liquid oozes out inside the blow-molded product. It is suppressed. Furthermore, since the taper surface 5e is provided on the peripheral edge 5f of the insert part 5, the insert part 5 and the blow molded article body 7 are easily fused even at the peripheral edge 5f of the insert part 5, and the liquid oozes more reliably. It is suppressed.

  Examples of blow-molded products that can be produced by the above method include various blow-molded products that use insert parts having openings such as tanks that contain water, gasoline, etc., pipes that have injection ports, and the like.

1: Injection port 3: Tank 5: Insert part 7: Blow molded product body 11: Parison 13a, 13b: Split mold

Claims (7)

A blow molding insert component comprising a cylindrical portion having an opening and a flange portion provided around the cylindrical portion, and fused to a blow molded product body by blow molding,
On the bottom surface of the flange portion, which is fused to the blow molded product main body, includes an easy-melting portion that surrounds the opening and is more easily melted than the flange portion,
The flange portion includes a base portion having a constant thickness and a peripheral portion provided on a peripheral edge of the base portion.
The peripheral edge portion is provided on both sides with tapered surfaces whose thickness decreases in the diameter-enlarging direction ,
The easy melting portion in the radial direction outward from the edge of the opening, Ru is provided on the base part, the insert part for blow molding. The insert part according to claim 1, wherein the easy melting part is configured by a thin protrusion. The insert part according to claim 2, wherein the thin protrusion has a thickness of 1 mm or less and a height of 0.5 mm or more. The insert part according to claim 2, wherein the thin protrusion has a ring shape surrounding the opening. The insert part according to any one of claims 1 to 4 , wherein a thickness of the peripheral portion is smaller than a thickness of the base portion. The insert part according to claim 5 , wherein the peripheral edge portion is provided at a position biased toward the bottom surface side. The said peripheral part is an insert component as described in any one of Claims 1-6 in which the front-end | tip is sharp.