JP2001205668A - Method for manufacturing hollow resin molding with auxiliary implement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a hollow resin molding with an auxiliary implement whose molding can be finished in a short time, by eliminating a position of re-integration by splitting a molten resin into two at a protrusion, eliminating a weld mark on a surface of the molding and fixing the implement rigidly to the molding. SOLUTION: The method for manufacturing the hollow resin molding mounted with the auxiliary implement comprises the steps of mounting the implement 18 at a core 11 of a mold, closing a pair of molds 5, 11, then injecting a resin composition in a cavity 12 of the mold, then ejecting a gas and integrating the molding with the implement 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow resin molded article with an assisting tool, and more particularly, to a hollow resin molded article applicable to bathtub products such as bathtub grips and bars. The present invention relates to a method for manufacturing a hollow resin molded article with an auxiliary tool integrally provided with such an auxiliary tool.

[0002]

2. Description of the Related Art As a conventional grip for a bathtub, a cast stainless steel product which does not easily generate rust has been used. In addition, recently, in order to reduce the weight, a resin in which a white filler or another pigment is added to a synthetic resin such as a polyamide resin or a modified PPE resin has been proposed. Particularly, in order to reduce the weight, a method is known in which a molten resin is poured into a mold cavity by a gas injection molding method, and a gas is injected before the resin is cured to make the inside of the molded body hollow. Have been. And
Since the product had to be mounted on the bathtub body, an insert nut was subsequently mounted on the molded body. The place where this insert nut is installed is a concave portion.

[0003]

However, since the projections for forming the recesses are fixed to the mold, the projections hinder the flow of the molten resin at the time of casting, which is a major cause of weld marks. Had become. FIG. 7 shows a bottom view of the bathtub grip. The bathtub grip 30 is composed of an arched grip body 31 and a pair of mounting surfaces 32.
Each has a recessed insertion hole 34 for the insert nut and one gas injection port 35, and a weld mark is generated from the vicinity of the insertion hole 34 of the insert nut in the flow direction of the resin. This weld mark is likely to be generated at a location where the molten resin is divided into two at the projection and merges again, and looks streaky in appearance.

In view of these points, the present invention eliminates the point where the molten resin is divided into two at the protrusions and reunites, eliminates the weld mark on the surface of the hollow resin molded product, and uses an auxiliary tool. An object of the present invention is to provide a method of manufacturing a hollow resin molded body with an auxiliary tool, which can be firmly fixed to the hollow resin molded body and can be completed in a short time.

[0005]

That is, the invention according to claim 1 of the present application is directed to a method of manufacturing a hollow resin molded article provided with an auxiliary tool, wherein the auxiliary tool is mounted on one of the molds.
After closing the pair of molds, the resin composition is injected into the cavity in the mold, followed by injecting gas to produce a hollow resin molded body with the auxiliary tool and the hollow tool and the auxiliary tool integrated. The auxiliary tool is installed in one mold in advance so that it protrudes slightly from the inner surface of the mold. It is possible to finish the mounted hollow resin molded body. In addition, there is no need to perform an operation of attaching an auxiliary tool after molding, and the auxiliary tool can be firmly fixed to the hollow resin molded body.

According to a second aspect of the present invention, there is provided a method of manufacturing a hollow resin molded article having an auxiliary tool mounted thereon, wherein the auxiliary tool is mounted on one of the molds and a pair of opposed molds is provided. After the parison is installed, the pair of molds are closed and blow-molded, and there is a method of manufacturing a hollow resin molded body with an auxiliary tool integrated with the hollow molded body and the auxiliary tool, eliminating the work of attaching the auxiliary tool after molding. Alternatively, the auxiliary tool can be firmly fixed to the hollow resin molded body.

[0007]

FIG. 1 is a sectional view of a mold apparatus according to the present invention. In the mold apparatus 1 of the present invention, the tip of the screw 4 installed in the cylinder 3 of the injection molding machine 2 is connected to the spool bush 6 provided on the fixed mold 5 and connected to the sprue 7 and the runner 8. This runner 8 is a fixed type 5
Provided in the core mold 1 via the runner gate 10.
1 to the cavity 12 formed between the two.

On the other hand, a gas injection means 13 for injecting a gas into the cavity 12 is provided in the core mold 11.
0, and immediately after the molten resin 9 of the cylinder 3 is injected into the cavity 12 via the sprue 7, the runner 8, and the runner gate 10, an inert gas such as nitrogen gas is introduced into the cavity 12. Send to In the gas injection means 13, the rear end of the gas nozzle 15 is connected to the gas supply path 16, and the front end is fixed to the core mold 11.

An auxiliary tool 18 such as a pair of mounting bolts is mounted at a predetermined position on the core mold 11. This auxiliary tool 1
Numeral 8 indicates that the hollow resin molded body 25 can be easily mounted on a wall surface, and has a shape in which a disk 20 made of synthetic resin is fixed to a bolt 19 as shown in FIG. Bolt 19
And the disk body 20 are mounted on the core mold 11, and the bolt head 21 is slightly projected into the cavity 12 and fixed. If the bolt head 21 protrudes greatly, the flow of the molten resin 9 is disturbed, and a weld mark is easily generated.

However, in the manufacturing method of the present invention, first, as shown in FIG.
The core mold 11 equipped with the gas injection means 13 and the auxiliary tool 18 is clamped by the movable mold 24. The mold temperature at this time is 20 ~
Adjusted to 80 ° C. Thereafter, the synthetic resin is charged into the cylinder 3 of the injection molding machine 2 and melted.
Inject The molten resin 9 is supplied from the sprue 7 to the runner 8,
Then, it is sent into the cavity 12 through the runner gate 10. The amount of the molten resin to be injected is set in consideration of the volume of the hollow portion of the molded product.

At this time, the molten resin 9
It does not disturb the flow and flows evenly, preventing the occurrence of weld marks.

Thereafter, the gas injection means 13 is operated while the molten resin is not solidified, and an inert gas such as nitrogen gas is sent from the gas nozzle 15 into the molten resin. As shown in FIG. A hollow resin molded body 25 having good appearance without weld marks and having gas passages formed in the unsolidified region of the portion is obtained. Also, the disk 2 of the bolt 19
If 0 is the same type of resin as the molten resin, it can be easily integrated with the molten resin to finish the hollow resin molded body 25 on which the auxiliary tool 18 is firmly attached.

The transparent synthetic resin used here includes:
Polypropylene resin, acrylic resin, polyamide resin,
ABS resin, polyethylene terephthalate resin, polycarbonate resin and the like can be mentioned.

Further, a flat glittering material can also be added. The glitter material has a particle size of 20 to 300 μm, and is added in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the transparent synthetic resin. Further, as the glitter material, aluminum flake having a particle size of 20 to 100 μm or a particle size of 50 to 100 μm can be used.
A glass flake coated with a metal having a thickness of 300 μm. The aluminum flake has a rounded shape made of weld-improved aluminum. For example, there is a METAX G type (particle size: 60 μm) manufactured by Toyo Aluminum.
On the other hand, the metal-coated glass flakes are obtained by sputtering an alloy of silver and tin on the surface. If the added amount of the flat glittering material is less than 0.1 part by weight, no glitter and heavy feeling will appear, while if it exceeds 5 parts by weight, the fluidity of the molten resin is impaired, and the glittering material becomes uniform. Plane orientation is lost. In the present invention, a pigment or the like can be added in addition.

In the present invention, as shown in FIGS. 5 and 6, an air cylinder 29 and an auxiliary tool 18 are mounted on one core mold 26 of a blow molding mold, and the mold on the other cavity side opposed to the other mold side. After extruding a parison 28 made of a synthetic resin melted between 27, a pair of dies 26 and 27 are closed, air is sent from an air cylinder 29 and blow molded, and the hollow resin molded body 25 and the auxiliary tool 18 are integrated. It can also be converted.

As the parison 28 used here, polypropylene resin, acrylic resin, polyamide resin, A
Examples include BS resin, polyethylene terephthalate resin, and polycarbonate resin.

[0017]

The present invention will be described in more detail with reference to the following examples. Example 1 To 100 parts by weight of a polypropylene resin, 0.5 parts by weight of aluminum flake METAX G type (particle size: 60 μm) (manufactured by Toyo Aluminum Co., Ltd.), 0.4 parts by weight of a stabilizer, 0.04 parts by weight of a pigment, and 0.1 part by weight of a dispersant. 5 parts by weight were added, mixed well, and melt-kneaded with a twin-screw extruder to prepare pellets. After mounting a mold device in which a gas injection means and an auxiliary tool were mounted on a core mold to an injection molding machine, the pellets were charged into a screw and melted, and the molten resin was injected into a cavity. The amount of injected resin was adjusted to 55% of the cavity volume. At this time, the slide pin was retracted from the inside of the cavity.

Immediately after the injection molding and before the molten resin in the cavity was solidified, nitrogen gas was fed from the gas nozzle into the molten resin to complete the molding. The obtained molded article was able to obtain an integrally molded article in which the auxiliary tool was firmly fixed to the hollow resin molded article. In addition, no weld mark was observed near the auxiliary tool.

Example 2 One of the blow molding dies whose temperature was adjusted to 50 ° C.
After installing an air cylinder and an auxiliary tool similar to that in Example 1, a parison made of a thermoplasticized polypropylene resin was extruded from an extruder between the other molds similarly adjusted to 50 ° C. The mold was closed, and air was sent from an air cylinder to perform blow molding, and the hollow molded body and the auxiliary tool were integrated to form a hollow resin molded article with the auxiliary tool. In the obtained molded article, the auxiliary tool was firmly fixed to the hollow resin molded article.

[0020]

As described above, according to the invention claimed in the present application, an auxiliary tool is attached to one of the molds, and after closing the pair of molds, the resin composition is introduced into the cavity in the mold. Inject,
Subsequently, there is a method of manufacturing a hollow resin molded body with an auxiliary tool in which a gas is injected to integrate the hollow molded body and the auxiliary tool, and the auxiliary tool is previously set in one of the molds so as to slightly protrude from the inner surface of the mold. By preventing the splitting and merging of the molten resin and allowing the molten resin to flow uniformly, it is possible to finish the hollow resin molded body equipped with an auxiliary tool with good appearance without weld marks, and to attach the auxiliary tool after molding. It is not necessary to do so, and the auxiliary tool can be firmly fixed to the hollow resin molded body.

In the invention according to the second aspect of the present invention, an auxiliary tool is attached to one of the molds, a parison is installed between a pair of opposed molds, and then the pair of molds is closed to blow molding. However, there is a method of manufacturing a hollow resin molded body with an auxiliary tool in which the hollow molded body and the auxiliary tool are integrated, and there is no need to perform an operation of attaching the auxiliary tool after molding, and the auxiliary tool is firmly formed by the hollow resin molding. Can be fixed to the body.

[Brief description of the drawings]

FIG. 1 is a view showing a state immediately after a molten resin is injected into a cavity in a manufacturing method of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a front view of an auxiliary tool used in the manufacturing method of the present invention.

FIG. 4 is a partially enlarged view of a hollow resin molded article with an auxiliary tool obtained by the production method of the present invention.

FIG. 5 is a view showing a state in which a parison is extruded between a pair of opposed molds in the production method of the present invention.

FIG. 6 is a diagram showing a state in which a pair of molds to which an auxiliary tool is mounted is closed and blow molded in the manufacturing method of the present invention.

FIG. 7 is a bottom view of a conventional bathtub grip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold apparatus 2 Injection molding machine 5 Fixed mold 7 Sprue 8 Runner 10 Runner gate 11 Core mold 12 Cavity 13 Gas injection means 15 Gas nozzle 18 Auxiliary tool 20 Disc body 21 Bolt head 24 Movable mold 25 Hollow resin molding

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29L 22:00 B29L 22:00 F term (Reference) 2D032 AA07 4F206 AA11 AA21 AB11 AB16 AH49 JA05 JB12 JN27 JQ81 4F208 AA11 AA21 AB11 AB16 AH49 LA01 LB01 LB12 LG23 LJ09 LN06

Claims (2)

[Claims] In a method for manufacturing a hollow resin molded article having an auxiliary tool, the auxiliary tool is mounted on one of the molds, and after closing the pair of dies, the resin composition is placed in the mold. A method for producing a hollow resin molded body with an auxiliary tool, wherein the hollow molded article and the auxiliary tool are integrated by injecting the gas into the cavity and then injecting a gas. 2. A method of manufacturing a hollow resin molded article equipped with an auxiliary tool, wherein the auxiliary tool is mounted on one of the molds, and a parison is placed between a pair of opposed molds.
A method for producing a hollow resin molded body with an auxiliary tool, wherein a pair of molds is closed and blow-molded to integrate the hollow molded article and the auxiliary tool.