JP6849902B2 - Manufacturing method of resin molded products - Google Patents

Description

The present invention relates to a method for producing a resin molded product, which is formed by laminating a skin material on a thermoplastic resin sheet.

Conventionally, there is known a method in which a thermoplastic resin sheet and a decorative sheet (skin material) are laminated and laminated to decorate a resin molded product (see, for example, Patent Document 1).

In Patent Document 1, a step of arranging a molten thermoplastic resin sheet on the side of the cavity so as to protrude around the cavity in a separated state from the mold cavity, and a stage of arranging the arranged thermoplastic resin sheet. In the first enclosed space formed in cooperation with the cavity, the decorative sheet is held so as to face the thermoplastic resin sheet and to protrude from the cavity of the mold so as to protrude around the cavity. The surface-bonded thermoplastic resin sheet and decorative sheet are attached to the cavity by the stage of surface-bonding the plastic resin sheet so as to be laminated and by vacuum-sucking the inside of the first closed space from the cavity side. A decorative molding method having a step of pressing and shaping is disclosed.

However, in Patent Document 1, since the skin material is combined with the plastic resin sheet extruded from the T-die and sent out from a pair of rollers to be bonded, they can be bonded to areas other than the desired region or as burrs after molding. There is a problem that the epidermis material is wasted because a part to be excised is generated.

Japanese Unexamined Patent Publication No. 2015-104886

The present invention has been made in view of such circumstances, and an object of the present invention is resin molding in which a skin material can be bonded only to a desired region when the skin material is bonded to the surface of a thermoplastic resin sheet. It provides a method of manufacturing an article.

The present invention is grasped by the following configuration.
(1) The first viewpoint according to the present invention is a method for manufacturing a resin molded product, in which a step of arranging a skin material on at least a part of the surface of a cavity of a mold and a thermoplastic resin sheet in a molten state are provided. A step of hanging the cavity sideways, a step of molding the mold and surface-adhering the skin material to the thermoplastic resin sheet so as to be laminated, and the thermoplastic resin sheet and the skin material. It is characterized by including a step of vacuum suction from the cavity side.

(2) In the configuration of (1) above, the skin material has fine through holes, and in the vacuum suction step, the thermoplastic resin sheet is sucked through the through holes.

(3) In the configuration of (2) above, the through hole of the skin material is configured to be closed after the vacuum suction step.

(4) In any one of the above (1) to (3), the skin material is composed of a decorative resin layer and a base material layer, and the decorative resin layer is formed on the thermoplastic resin sheet. It is bonded and the base material layer is peeled off.

(5) A second aspect of the present invention is a skin material that is bonded to a thermoplastic resin sheet to form a resin molded product, has fine through holes, and is bonded to the thermoplastic resin sheet. After that, the through hole is configured to be closed.

According to the present invention, when the skin material is bonded to the surface of the thermoplastic resin sheet, it is possible to provide a method for producing a resin molded product in which the skin material can be bonded only to a desired region.

It is an overall front view which shows the molding apparatus which carries out the manufacturing method of the resin molded article which concerns on 1st Embodiment of this invention. FIG. 5 is a cross-sectional view showing a process of arranging a skin material and a thermoplastic resin sheet in a mold in the molding apparatus of FIG. It is sectional drawing which shows the process which closed the space between the thermoplastic resin sheet and the cavity of a mold by a mold from the aspect shown in FIG. 2 in the molding apparatus of FIG. It is sectional drawing which shows the process of closing a mold and molding from the aspect shown in FIG. 3 in the molding apparatus of FIG. It is a perspective view of the front side of the resin molded article molded by the molding apparatus of FIG. It is a side view of the resin molded article molded by the molding apparatus of FIG. It is sectional drawing which shows the process of arranging a pair of thermoplastic resin sheets and a skin material in a mold in the molding apparatus which carries out the manufacturing method of the resin molded article which concerns on 2nd Embodiment of this invention. FIG. 5 is a cross-sectional view showing a process of closing a pair of thermoplastic resin sheets and a cavity of a mold with a mold from the aspect shown in FIG. 7 in the molding apparatus of FIG. 7. FIG. 5 is a cross-sectional view showing a process of vacuum-adsorbing a pair of thermoplastic resin sheets and a skin material into the corresponding mold cavities from the aspect shown in FIG. 8 in the molding apparatus of FIG. 7. It is sectional drawing which shows the process of molding by molding a mold from the aspect of FIG. 9 in the molding apparatus of FIG. FIG. 5 is a cross-sectional view showing a step of opening a mold and taking out a resin molded product from the aspect of FIG. 10 in the molding apparatus of FIG.

(Embodiment)
Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. The same elements are numbered the same throughout the description of the embodiment.

(First Embodiment)
First, with reference to FIGS. 1 to 5, a method for manufacturing the resin molded product 16 according to the first embodiment using the molding apparatus X for one thermoplastic resin sheet P will be described. As shown in FIG. 1, the molding apparatus X includes an accumulator 1, a plunger 2, a T die 3, an extruder 4, a thermoplastic resin supply hopper 5, a pair of rollers 6, 6, and a pair of molds 7, 8. ing. After being melt-kneaded by the extruder 4, the thermoplastic resin is temporarily stored in the accumulator chamber in the accumulator 1 and supplied to the T-die 3 by the plunger 2 at regular intervals. The molds 14 and 15 are located on the outer circumferences of the molds 7 and 8, and the T-die 3 has a slit at the tip of the T-die 3 in order to adjust the thickness of the thermoplastic resin sheet P. A slit gap adjusting device 19 for adjusting the gap spacing is provided.

Specifically, first, the extrusion speed is set by the accumulator 1 and the T die 3. The extrusion capacity of the extruder 4 connected to the accumulator 1 can be appropriately selected depending on the size of the resin molded product 16, but it is preferably 100 kg / hour or more from the viewpoint of shortening the molding cycle. Therefore, the thermoplastic resin stored in the accumulator chamber of the accumulator 1 is extruded from the opening of the slit of the T die 3 at 50 kg / hour or more, preferably 60 kg / hour or more per ^{1 cm 2.}

The thermoplastic resin supplied to the T-die 3 is extruded as a thermoplastic resin sheet P from a manifold of the main body of the T-die 3 (not shown) through a resin flow path and a slit. The T-die 3 main body is formed by superimposing a pair of dies, and one die lip and the other die lip face each other with a slit gap at the tip portion of the T-die 3 main body, and the slit gap spacing is adjusted by the slit gap adjusting device 19. Set. The thickness of the thermoplastic resin sheet P extruded by the slit gap is determined. Specifically, it is extruded from the T die 3 as a thermoplastic resin sheet P having a thickness of 0.6 to 6.0 mm.

The slit clearance adjusting device 19 of the main body of the T-die 3 includes a thermal expansion type and a mechanical type, and it is preferable to use a device having both functions. A plurality of slit gap adjusting devices 19 are arranged at equal intervals along the width direction of the slits, and the slit gap adjusting device 19 narrows or widens the slit gaps to reduce the thickness of the thermoplastic resin sheet P in the width direction. Make it uniform.

Specifically, as the mechanical adjusting means, a die bolt provided so as to be able to advance and retreat toward one of the die lips (not shown) is provided, and an adjusting shaft is arranged at the tip thereof via a pressure transmitting portion. An engaging piece is connected to the adjusting shaft by a fastening bolt, and the engaging piece is connected to one of the die lips. When the die bolt is advanced, the adjusting shaft is extruded toward the tip through the pressure transmission portion, and one die lip is pressed. As a result, the die lip is deformed at the portion of the concave groove and the slit gap is narrowed. To widen the slit gap, reverse the die bolt. Further, the slit gap can be adjusted with high accuracy by using the thermal expansion type adjusting means in accordance with the mechanical adjusting means. Specifically, by heating the adjusting shaft with an electric heater (not shown) and thermally expanding it, one die lip is pressed and the slit gap is narrowed. Further, in order to widen the slit gap, the electric heater is stopped, and the adjusting shaft is cooled and contracted by a cooling means (not shown).

The thermoplastic resin sheet P extruded from the opening of the slit of the T die 3 is sent out by being sandwiched between a pair of rollers 6 and 6 in order to prevent the thickness from being varied due to drawdown, neck-in, and the like. Is done.

For the thermoplastic resin sheet P extruded from the opening of the slit of the T die 3, it is preferable to use an amorphous thermoplastic resin material having high fluidity in order to improve transferability and followability to the mold. Specifically, melt tension at 230 ° C. (using a melt tension tester manufactured by Toyo Seiki Seisakusho Co., Ltd., with a residual heat temperature of 230 ° C., an extrusion speed of 5.7 mm / min, and a strand from an orifice having a diameter of 2.095 mm and a length of 8 mm. Extruded, the tension when the strand is wound on a roller having a diameter of 50 mm at a winding speed of 100 rpm) is 50 mN or more, MFR at 200 ° C., test temperature 200 ° C., test load 2 according to JIS K-7210. Use a resin material that weighs 3.0 to 60 g / 10 minutes (measured at .16 kg), more preferably 30 to 50 g / 10 minutes. For example, acrylonitrile-butadiene-styrene copolymer, polystyrene, high impact polystyrene (HIPS resin), acrylonitrile-styrene copolymer (AS resin) or a mixture thereof can be used.

As shown in FIG. 2, the molten thermoplastic resin sheet P extruded from the T die 3 hangs down between a pair of rollers 6 and 6 arranged at intervals. The pair of rollers 6 and 6 can be opened and closed by an opening / closing mechanism (not shown), and the distance between the pair of rollers 6 and 6 can be adjusted by the opening / closing mechanism. The thermoplastic resin sheet P sent out by the pair of rollers 6 and 6 is arranged between the molds 7 and 8. The mold 8 is provided with a cavity 9, and the cavity 9 may have a textured transfer surface to be transferred to the resin molded product 16.

Here, in the present embodiment, the skin material 18 (a decorative sheet for applying decoration such as wood grain to the surface of the thermoplastic resin sheet P) is arranged on at least a part of the surface of the cavity 9. This is for adhering the skin material 18 to a desired region of the thermoplastic resin sheet P. Details of the skin material 18 will be described later.

Subsequently, as shown in FIG. 3, the molds 14 and 15 located on the outer periphery of the molds 7 and 8 are advanced relative to the molds 7 and 8 and adhere to the molten thermoplastic resin sheet P. Let me. The mold 8 is provided with a vacuum suction chamber 10 and a suction hole 11 on the back side of the cavity 9, and by vacuum suction from the suction hole 11, the thermoplastic resin sheet P and the skin material 18 are combined into the cavity 9. It is adsorbed so that the shape generally follows the shape of the cavity 9.

Next, as shown in FIG. 4, the thermoplastic resin sheet P is placed along the cavity 9 and then the mold is fastened, and the pressurized fluid is introduced into the molds 7 and 8 from the pressure fluid introduction hole 12 provided in the mold 7. By blowing, the thermoplastic resin sheet P and the skin material 18 are pressure-formed into a shape along the cavity 9. As a result, the skin material 18 is bonded to the surface of the thermoplastic resin sheet P, and the textured pattern having an uneven shape is transferred. After that, the resin molded product 16 cooled in the molds 7 and 8 is completed by opening the molds 7 and 8 and releasing the mold, and then removing the burrs on the outer periphery.

The skin material 18 will be described in detail. FIG. 5 shows an example of a resin molded product 16 in which the skin material 18 is bonded to the surface 17. In the present embodiment, as shown in the drawing, the skin material 18 is bonded to a desired region of the resin molded product 16.

By laminating the skin material 18 to the resin molded product 16, a resin molded product 16 having a multi-layer structure made of a plurality of different resins can be obtained. The skin material 18 has a function of improving appearance, a decorative property, and a function of protecting an object in contact with a molded product. The form of the skin material 18 is a sheet, a film, or the like, and a resin sheet having a printing layer on the outer surface, a transparent or colored resin sheet, synthetic leather, or the like having a thickness of 0.1 to 3.0 mm can be used. If the thickness of the skin material 18 is too large, it does not follow the shape of the mold and molding becomes difficult.

Examples of the material of the skin material 18 include polyester, polypropylene, polyamide, polyurethane, acrylic resin, and thermoplastic elastomer. In the present embodiment, in order to attach the skin material 18 to the surface of the resin molded product 16, the skin material 18 is arranged in advance on the surface of the cavity 9 of the mold 8 as described above. As a method of arrangement, for example, the skin material 18 can be attached to the cavity 9. Then, by vacuum-sucking the thermoplastic resin sheet P from the side of the skin material 18, the thermoplastic resin sheet P and the skin material 18 can be bonded and integrated by heat welding. At the same time, the grain pattern can be transferred to the side to which the skin material 18 of the resin molded product 16 is attached.

The structure of the skin material 18 will be described. As shown in FIG. 6, the skin material 18 includes a decorative resin layer 181 and a base material layer 182. The base material layer 182 is attached to the cavity 9, and the decorative resin layer 181 is attached to the thermoplastic resin sheet P. Here, vacuum is sucked from the side of the skin material 18, but since the skin material 18 is a material as described above, it is not breathable unlike a non-woven fabric or the like. Therefore, the skin material 18 is provided with fine through holes 18a in order to constantly attract the skin material 18 and the thermoplastic resin sheet P. As a result, when vacuum suction is performed from the vacuum suction chamber 10 and the suction hole 11 provided on the back side of the cavity 9 of the mold 8, the thermoplastic resin sheet P can be reliably sucked through the through hole 18a. Here, as will be described later, a crystallization retarder is mixed in the decorative resin layer 181 and even if the through hole 18a is provided, the through hole 18a is finally closed and the surface is clean. A resin molded product 16 can be obtained. Further, the decorative resin layer 181 containing the crystallization retardant can prevent the suction holes 11 of the mold 8 from being transferred to the resin molded product 16 and deteriorating the appearance. The base material layer 182 can be selected from materials that can be attached to the thermoplastic resin sheet P, and more preferably the same material. Further, the crystallization retarder may be mixed at least in the decorative resin layer 181 but may also be mixed in the base material layer 182.

As shown in FIG. 6, the base material layer 182 is peeled off after molding, but if the through holes 18a remain in the decorative resin layer 181, the aesthetic appearance of the resin molded product 16 is impaired. Therefore, in the present embodiment, the through hole 18a remaining in the decorative resin layer 181 is closed by the following means. For example, when the decorative resin layer 181 is made of polypropylene, the crystallization temperature is lowered by 10 ° C. or more by mixing a crystallization retarder, and the through hole 18a is closed. When the crystallization retardant is mixed in this way to lower the melting temperature, the thermoplastic resin sheet P is sucked through the through hole 18a, and the thermoplastic resin sheet P and the skin material 18 are bonded by heat welding. After the integration, the melting time of the skin material 18 can be lengthened, and the through holes 18a are closed during the mold clamping molding.

Explaining the mechanism of this ring closure, the crystallization temperature of the decorative resin layer 181 is lowered due to the inclusion of the crystallization retarder. Therefore, even if the molding step is carried out as in the conventional case, it is possible to maintain a long time until the skin material 18 is cooled and solidified. Then, while the crystallization is delayed, the decorative resin layer 181 contracts (see the arrow shown in FIG. 6) and acts to close the through hole 18a. As a result, the decorative resin layer 181 is transferred to the thermoplastic resin sheet P without any problem in terms of aesthetic appearance. Since the through hole 18a is fine (for example, about 300 μm), the thermoplastic resin sheet P does not enter the through hole 18a.

As the crystallization retarder, for example, a polyolefin-based resin such as atactic polypropylene or silicone oil can be used. Specific examples of silicone oil include dimethylpolysiloxane, monomethylpolysiloxane, methylphenylpolysiloxane, alkyl-modified silicone, amino-modified silicone, epoxy-modified silicone, carboxyl-modified silicone, mercapto-modified silicone, alkyl higher alcohol-modified silicone, and alcohol-modified silicone. , Chloroalkyl-modified silicone, polyether-modified silicone, fluorine-modified silicone and the like.

The diameter, the number of arrangements, and the pitch of the through holes 18a of the skin material 18 will be described. Since the through hole 18a of the skin material 18 is set to be finally closed as described above, it is generally configured to have a diameter smaller than that of the suction hole 11 of the mold 8 (the skin shown in FIG. 6). Refer to the positional relationship between the through hole 18a of the material 18 and the suction hole 11 of the mold 8). Since it is difficult to change the suction holes 11 of the mold 8 each time molding is performed, the diameter, the number of arrangements, and the pitch of the through holes 18a of the skin material 18 are appropriately set each time molding is performed in order to obtain the effect of vacuum suction. Will be done. For example, the number of through holes 18a may be increased in order to strengthen the pull of vacuum suction, or the diameter of the through holes 18a may be reduced to twice or less the thickness of the decorative resin layer 181 to ensure ring closure. The pitch of the through holes 18a is set to 30 mm or less so as not to completely block the suction holes 11 of the mold 8.

(Second Embodiment)
A method for manufacturing the resin molded product 16 according to the second embodiment using the molding apparatus Y for the two thermoplastic resin sheets P will be described with reference to FIGS. 7 to 11. As shown in the drawing, the molding apparatus Y manufactures a resin molded product 16 using a pair of thermoplastic resin sheets P and P, and includes an accumulator 1, a plunger 2, a T die 3, and an extruder 4. Each of the thermoplastic resin supply hopper 5 and the pair of rollers 6 and 6 is separately arranged corresponding to the pair of thermoplastic resin sheets P and P. The same parts as those of the first embodiment shown in FIGS. 1 to 6 are designated by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, the resin molded product 16 having a hollow double wall structure is molded by the pair of thermoplastic resin sheets P and P in the same manner as in the first embodiment. Here, an example is shown in which the skin materials 18 and 18 are laminated on the surfaces of both walls of the resin molded product 16 having a hollow double wall structure, but of course, the skin materials 18 are formed only on the surface of one wall. May be laminated. Further, the grain pattern formed by the cavity 9 can also be transferred to both or one of the skin materials 18 and 18.

Although the present invention has been described above with reference to the embodiments and examples, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. Further, it is clear from the description of the scope of claims that the form to which such a modification or improvement is added may be included in the technical scope of the present invention. In addition, this embodiment can be applied regardless of whether the object S to be polished is a molded product by blow molding or a molded product by injection molding.

1 ... Accumulator 2 ... Plunger 3 ... T-die 4 ... Extruder 5 ... Thermoplastic resin supply hopper 6, 6 ... Pair of rollers 7, 8 ... Mold 9 ... Cavity 10 ... Vacuum suction chamber 11 ... Suction hole 12 ... Pressure Fluid introduction holes 14, 15 ... Mold 16 ... Resin molded product 18 ... Skin material 19 ... Slit gap adjusting device P ... Thermoplastic resin sheet

Claims (4)

It is a manufacturing method of resin molded products.
With the step of placing the skin material on at least a part of the surface of the mold cavity,
A step of hanging a molten thermoplastic resin sheet extruded from a T-die to the side of the cavity, and
A step of mold-fastening the mold and surface-adhering the skin material to the thermoplastic resin sheet so as to be laminated.
A step of vacuum-sucking the thermoplastic resin sheet and the skin material from the cavity side is provided .
The skin material has fine through holes, and in the vacuum suction step, the thermoplastic resin sheet is sucked through the through holes.
A manufacturing method further comprising a step of mixing a crystallization retarder into the skin material, and the through hole of the skin material is closed after the vacuum suction step. The claim is characterized in that the skin material is composed of a decorative resin layer and a base material layer, the decorative resin layer is attached to the thermoplastic resin sheet, and the base material layer is peeled off. The manufacturing method according to 1. A skin material that is bonded to a thermoplastic resin sheet to form a resin molded product.
Has fine through holes
A crystallization retarder is mixed in the skin material,
A skin material characterized in that the through holes are closed after being bonded to the thermoplastic resin sheet. It has a decorative resin layer and a base material layer,
The skin material according to claim 3 , wherein the crystallization retarder is mixed in the decorative resin layer.

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