JP2002018882A - Method and equipment for manufacturing plastic molded article having foamed resin layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To consecutively execute processes from molding of a plastic sheet to molding of a foamed resin layer, omitting a process of altering a molding tool and dispensing with heating of an appearance part before filling of a foamed resin material in the molding tool, and to perform proper molding with little energy. SOLUTION: A plate-shaped thermoplastic synthetic resin sheet A is held in stretch on a clamping frame 2 slidable on a running rail 1 and heated to be softened by a heating means of a heater 3. Then, the sheet A softened by heating is put on the porous molding tool 41 and it is brought into close contact with the tool by a compressed-air or vacuum-suction means and tool-molded. After this primary processing, the molding tool 41 holding the tool-molded sheet is used for a bottom tool as one of foamed resin layer molding tools 4 for molding the foamed resin layer and clamped together with a top force of the other foamed resin layer molding tools 5. The foamed resin material is filled in the mold by a material supply mechanism, e.g. a hopper, an introducing unit or piping, and foamed by heating. Thereby the foamed resin layer B is laminated on and welded to the sheet to be integrated therewith and a molded article is made by cooling. After this secondary processing, the molded article is released from the foamed resin layer molding tools 4 and 5 and taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molded article having a foamed resin layer having excellent heat insulating properties, cushioning properties and sound absorbing properties, and in particular, automobile parts, building materials, household goods, electric parts, coolers and inner boxes of electric refrigerators. The present invention relates to a method and an apparatus for manufacturing a plastic molded article having a foamed resin layer suitable for, for example, the present invention.

[0002]

2. Description of the Related Art Generally, as a plastic molded product used for a surface covering material of a building material or an interior of a vehicle, a base material of a plate-shaped thermoplastic synthetic resin sheet (hereinafter abbreviated as a sheet) is formed into an external appearance product. A product having a two-layer structure in which a foamed resin layer such as styrene foam of a heat insulating material is welded and integrally formed on the appearance product is known.

[0003]

Conventionally, a sheet is formed by a vacuum forming die to prepare an appearance product, which is set in a foaming resin molding die, and then vacuum-suctioned to form an appearance product. The foamed resin layer was formed while pulling the mold and steaming from one of the molds to soften the appearance, but this was because the appearance of the plastic sheet and the foamed resin layer were fused together. If the temperature of the product is not raised, the foamed resin layer that is in contact with the appearance product will not be foamed and fused.However, when setting the appearance product in the foam molding mold, Because it is different, complicated work to correct the foaming resin molding die many times is necessary,
And even if it is corrected many times, it is very difficult to accurately match the vacuum-formed appearance. Also, even if this is forcibly formed into a shape, distortion remains in the molded foam resin layer at the same time, it is impossible to prevent deformation, resulting in poor molding, and many correction processes There was a problem such as not being able to give. The present invention has been conceived in order to solve the above-mentioned drawbacks of the prior art, and performs the entire process from molding of a plastic sheet to molding of a foamed resin layer, omitting a step of correcting a molding die, and reducing foaming. A method for continuously and efficiently producing plastic molded products having a foamed resin layer with appropriate moldability with little energy without having to heat the appearance product before filling the resin material into the molding die And an apparatus thereof.

[0004]

SUMMARY OF THE INVENTION The method for producing a plastic molded article of the present invention is an integrated method in which a thermoplastic resin sheet is molded into an external appearance article by the same apparatus, and a foamed resin layer is integrally molded and fused sequentially. It is to obtain a plastic molded product having a foamed resin layer from the process. In the case of the present invention, a plate-shaped thermoplastic synthetic resin sheet is stretched and held on a clamp frame, heated and softened by heating means, and then the heated softened sheet is placed on a porous molding die, and the sheet is placed on the sheet. After the primary processing of forming the mold by bringing it into close contact with the forming mold by air or vacuum suction means, the forming mold holding the formed sheet is used as one of the foaming resin layer forming molds for forming the foaming resin layer. Used, closed the mold with another foamed resin layer molding die, and filled the foamed resin raw material in the mold and heat-foamed to integrally laminate and weld the foamed resin layer to the sheet,
After secondary processing to form a molded article by cooling, the molded article is released from the molding die and taken out consistently.

In this apparatus for manufacturing a plastic molded product, a clamp frame for stretching and holding a plate-like synthetic resin sheet is slidably provided on a traveling rail, and a heating mechanism is provided in a sheet traveling passage of the traveling rail. A primary processing mold that can be a foaming resin layer molding die, and a pressurized or vacuum forming mechanism that can arrange the molding die, and press-holds the primary processing mold to a sheet heated and softened by the heating mechanism. The foamed resin layer molding die is provided on a transport rail so as to be able to move up and down so as to be able to move up and down, and is further transferred to the end of the transport rail at the foamed resin layer molding position, and one of the foamed resin layers is moved. A layer forming mold, and the other foaming resin layer forming mold is movably mounted on the foaming resin layer forming mold so as to be vertically movable. The foamed resin layer of It is characterized in that a structure having a foamed resin layer forming mechanism in a metal mold.

Further, according to the present invention, a tool rest having a blade body for punching out and cutting an outer peripheral portion of the softened sheet pressed by the primary working mold is lifted and lowered between the vacuum forming mechanism and the foamed resin layer forming mechanism. It is characterized by having a freely provided trimming finishing mechanism and a transport rail circulating from the vacuum forming position through the trimming position to the foamed resin layer forming position in the order of the foamed resin layer forming position through the molded product take-out position. is there.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a method of manufacturing a plastic molded product according to the present invention, a plate-like resin sheet (ABS resin) is set on a clamp frame, then transferred on a traveling rail, and passed to a sheet heating position. At this time, the sheet is heated and softened from above and below to form a molding die (mold temperature 50 to 8).
(0 ° C.), press-fitting or pulling-in, press-forming or vacuum-forming means to form the mold at a molding temperature of 130 ° C. to 150 ° C. The primary processing is performed, and the molding die is conveyed to a trimming position and unnecessary portions of the resin sheet are cooled without cooling Is finished by punching and cutting with a blade, and then the molding resin sheet is brought into the foaming resin layer molding position without cooling while keeping the molding resin sheet in close contact with the vacuum, and the foaming resin layer molding mold is closed and molded. After filling the foamed resin layer raw material into a molding die containing a resin sheet and performing heat foam molding, directly fuse and integrate the foamed resin layer with the molded resin sheet, the molded product is cooled at a cooling position in the molding die. Performs secondary processing for cooling, and then releases the plastic molded product from the molding die at the molded product removal position,
There is no need to set and match the appearance of the resin sheet molding before filling the foaming resin layer raw material into the molding die, there is no need to heat the appearance, and there is a simple operation and a foaming resin layer with little energy A plastic molded product can be continuously and easily produced with remarkably good moldability, and the production cost can be greatly reduced.

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show one embodiment of the present invention, in which a plate-shaped thermoplastic synthetic resin sheet A is stretched and held on a slidable clamp frame 2 on a running rail 1 to heat a heater 3. is heated and softened by, put the sheet a was the heated and softened in the next to the molding die 4 ₁ porous, after the molding to primary processing in close contact with pressure or vacuum suction means in the molding die of the sheet a , used in the lower mold as one of the foamed resin layer molding die 4 for forming the foamed resin layer molding die 4 ₁ holding the molded sheets, on the other of the foamed resin layer molding die 5 The mold is closed with a mold, and the foamed resin material is filled into the mold by a raw material supply mechanism 11 such as a hopper, a charging device, each pipe, and heated and foamed, and the foamed resin layer B is integrally laminated and welded to the sheet. , After secondary processing to make a molded product by cooling, The molded article was released from the foamed resin layer molding die 4, 5 to be taken out as a plastic molded product C are to perform consistently.

In this case, the clamp frame 2 for stretching and holding the plate-like synthetic resin sheet A in a horizontal state is slidably provided on the traveling rail 1 so as to reciprocate on the traveling rail 1 by a transport mechanism. and can be arranged as upper and lower heater 3 of the heating mechanism to the sheet travel path of the running rail 1, and one of the foamed resin layer molding die 4 and will be primary processing molding die 4 _1, the primary processing molding die 4 ₁ and a pressure or vacuum forming mechanism 6, the lift cylinder 8 so as to be able to press and hold the primary processing molding die 4 ₁ sheet a heated softened by the heating mechanism, and deployed on a vertically movable cradle 7,
The primary processing molding die 4 ₁ is provided freely traveling on the conveying rails 9, a primary processing mechanism for forming the part to be preformed, one further transported to the transport rail end of the foamed resin layer molding position The foamed resin layer molding die 4 is used, and the other foamed resin layer molding die 5 is formed with respect to the foamed resin layer molding die 4.
And the other one of the foamed resin layer forming molds 5 transferred directly below the other foamed resin layer forming mold 5.
Thus, the secondary processing can be performed by providing the foamed resin layer forming mechanism 10.

[0010] The vacuum forming mechanism 6, between the foamed resin layer forming mechanism 10, tool rest 13 having a blade to resect punching an outer peripheral portion of the pressed softened sheet A in the primary processing molding die 4 ₁ And a transfer rail 9 circulating from the vacuum forming position through the trimming position to the foamed resin layer forming position in the order of the foamed resin layer forming position through the molded product take-out position and foaming. The manufacturing apparatus is configured as a plastic molded article having a resin layer.

[0011] For example, as shown in FIG. 3, the vacuum forming position F from the sheet setting position D through the heating position E primary processing molding die 4 ₁ is conveyed to ChoSo the sheet A, and the trimming position G A primary processing step line, a foaming resin layer forming position H including a vacuum forming position F and a trimming position G, and a foaming resin layer forming position H including a certain portion, are connected to each other. A secondary processing step line for circulating and transporting the foamed resin layer forming mold 4 from the position J to the vacuum forming position F, and a plastic molded product C in which the foamed resin layer B is integrated with a preformed sheet A It is preferable to configure an integrated production line (see FIG. 4).

As the plate-like sheet A, a plate-like sheet of polystyrene resin, vinyl chloride resin, polypropylene resin, ABS resin, acrylic resin, methacrylic resin, polyethylene resin, cellulosic resin or other plastics is compressed into a molding die. Alternatively, the resin may be pressed or drawn in by vacuum means, and the primary processing may be performed generally in the state shown in Table 1 under the vacuum forming conditions of these resins.

[0013]

[Table 1]

Further, as a forming means of the primary processing, the sheet A is clamped on a lower mold, for example, a female mold of the foamed resin layer forming mold 4, and the air in the mold is eliminated to form the sheet by atmospheric pressure. A plug that uses straight molding, which is formed by pressing on the mold surface, or a sheet that has been heated and softened using a male mold, is pushed up with a male mold, and then vacuum-sucked to make the sheet adhere to the mold, or a plug that uses a plug In addition to assist molding and plug assist reverse draw molding, in which pressurized air is sent from under the sheet before using the plug to pre-stretch the sheet, draw molding, air slip molding, snapback molding, reverse draw molding, Air-action molding, plug-assist air-slip molding, free molding, matched molding, plug ring molding,
Slip molding, contact heating molding and the like are appropriately selected and used.

In handling the resin sheet A in the primary processing, when the resin sheet A is cut into a predetermined size, the apparatus including the clamp frame 2 for clamping the resin sheet includes:
When the sheet A is heated and formed, the sheet is strongly held and used to support the sheet A so that the sheet does not fall off. The portion held by the clamp is removed after the forming and becomes a scrap. It is better to attach rubber or sponge to the clamp to increase frictional resistance, to provide a sharp projection on the clamp and to cut into the sheet, or to use a thin sheet for the upper clamp, attach the sharp projection to the lower clamp. Is considered to provide a concave portion to be fitted with the projection and to break through and hold the sheet. Note that, instead of the clamp frame 2, a form in which a roll-wound sheet is flowed and continuously formed may be employed. The sheet A
Is supplied to the clamp frame 2 by hand, is clamped and held by the holder portion, and is moved from the sheet setting position D to the vacuum forming position F by traveling conveyance means such as chain drive or rack and pinion drive of the clamp frame.

Further, the heater 3 of the resin sheet heating mechanism
In general, the sheet is heated and softened by radiation heating such as infrared rays radiated from a heat source in the range of 300 to 2200 ° C., convection heating by a hot air circulation furnace, or contact heating by a heating metal plate. For example, a resin sheet held horizontally from above and below by an upper heater (far infrared heater: 2.5 w / cm ² ) and a lower heater (sheath heater 2.0 w / cm ² ) is softened by heating.

[0017] The primary processing molding die 4 _1, for use as a molding die of the vacuum molding process, the vacuum forming position F, is fixed and held on the frame 7. That is, when the primary processing molding die 4 ₁ is conveyed onto the platform 7, the positioning cylinder 7
0 rises, the rod is fitted into the fitting hole 60 and positioned, and the vacuum suction member 72 is raised by the seal cylinder 71 to be connected and sealed to the vacuum suction port 61 of the vacuum forming mechanism 6. As a control system connected to 72, a primary processing of sheet vacuum forming can be performed by the vacuum device 14 via a pipe 73 and an ON-OFF valve 74, for example, an electromagnetic valve. Moreover, the mold 4 ₁ of the vacuum forming mechanism 6 is provided with wheels 62 for traveling gantry 7 for mounting this is provided in the vertically movable frame 76 via the guide pin 75, lifting the lift cylinder 8 The sheet A can be moved and pressed and held on the softened sheet A. For example pushes up the mold 4 ₁ of the vacuum forming mechanism 6 to the open ON-OFF valve 74 rises to a desired height by lifting cylinders 8 to the sheet A, mold 4 ₁
The inside is sucked, and the sheet A is brought into close contact with it to form a mold, thereby completing the primary processing. Each of the cylinders 8, 70, and 71 is provided in a hydraulic control system and can be sequentially operated with time. The vacuum device 14 including a vacuum pump evacuates the inside of a molding die to form a softened sheet A into an external part. By the way,
Primary processing can be performed. In this case, it is preferable that a transfer mechanism is used as the transfer mechanism of the vacuum forming mechanism 6, and that the control at the start and the stop can be automatically controlled using a detector such as a limit switch or a proximity switch. In order to position the mold, a matching pin 77 is protruded from the tapered surface of the mold so that the mold can be securely closed with the other mold 5 for forming the foamed resin layer.

Further, in the trimming position G, the trimming mechanism 12, the tool rest 13 is moved up and down in the cylinder 15, around unnecessary portions of ChoSo sheet A on primary processing molding die 4 ₁ is positioned directly below After excision
Transferring the molded mold die 4 ₁ to the foamed resin layer molding position H, it is used as a lower mold of the foamed resin layer molding die 4. In addition,
For the positioning of the molding die, the same control system and positioning mechanism as in the previous example are selected and used.

As shown in FIG. 5, the lower mold of the foamed resin layer molding mold 4 is positioned by the same positioning mechanism 40 as the vacuum molding position F. A bolster 19 having a bolster cylinder 18 is provided on a frame 20 so as to be able to move up and down so that a wheel 62 of a lower mold which is a foamed resin layer forming mold 4 is not damaged.
The bolster 19 is raised to receive a mold clamping force, and forms a foamed resin molding position H. Then, the primary processing molding die 4 ₁ is transported on the transport rails 9 through wheels 62, when it is set in the foamed resin molding position H, as the vacuum suction port 61 becomes steam inlet, The vacuum apparatus 21 is used as a lower mold of a foamed resin layer forming mechanism 10 provided via a steam nozzle 22 having a cylinder 23 and an on-off valve 24.

The upper mold of the foamed resin layer molding mold 5 is:
As shown in FIG. 6, a cavity is formed in the molding die 50, and the injection nozzle 51 and the eject pin 5 for the beads of the foamed resin material are used.
2 and a lower die aligning pin hole 53, and a molding die 5 for an upper die on a frame 16 that moves up and down on a diver 26 by a cylinder 25 connected to a converter 17 as shown in FIG. Further, it is connected to the raw material supply device 11 and the vacuum device 27, and is configured as a foamed resin layer forming mechanism.

The vacuum hole of the molding die varies depending on the thickness and the material of the molded sheet, but is generally up to 0.8 mmφ for molding a sheet having a thickness of 1.5 mm or more.
In the case of small tensile strength due to the molding temperature such as polyethylene or polypropylene, the
If it is not desirable to form a sheet of 0.5 mm or less and leave traces of holes, holes up to 0.3 mmφ are used. In this case, since the molded product is likely to warp and shrink when adjusting the mold temperature, it is usual to embed a pipe in the mold and adjust the temperature through cooling water, so that the entire mold is cooled uniformly.

Further, as the foamed resin layer B, polystyrene, polyethylene, polypropylene, foamed EVA
Resin, foamed polyvinyl chloride resin, thermoplastic resin foam such as polyurethane, phenolic resin, urea resin, epoxy resin, thermosetting resin foam such as hard polyurethane,
In particular, flexible foams have good cushioning and sound absorption properties,
It is effectively used for cushioning machines for stationery, medicine, electric equipment, etc., and sound absorbing materials.

The vacuum device 27 includes an accumulator having a capacity of 700 mmHg or more including a control panel (not shown) and a vacuum system control mechanism (vacuum pump,
And a pneumatic device connected to the mold table or including an accumulator and a pneumatic system control mechanism.

Next, in this embodiment, as the foamed resin layer forming mechanism 10, the heating time and the vacuum cooling time can be automatically controlled without using a timer by data processing of a computer unit (not shown). If necessary, fixed data of mold closing completion, cracking, ejecting, and mold closing completion can be input in the setting section.The interval between the molding dies, the detected foaming pressure is also an analog signal. As a digital signal, and the data processing unit controls the driving unit for moving and driving the molding die by comparing the internal fixed data with the internal fixed data to adjust the opening / closing operation of the molding die or continuously. In addition to automatically recording and displaying the operating status digitally while driving while displaying digitally, the results are processed and the opening and closing work of the molding die can be performed optimally under ideal conditions It is possible to safely and efficiently manufacture a plastic molded product having a foamed resin layer.

Further, it is possible to control devices including a driving unit in each section, and to automatically control the operation by comparing the data inputted to the computer unit by the setting unit. In this embodiment, the ABS
Taking the resin as an example, the molding temperature is 130 to 150 ° C. and the mold temperature is 50 to 80 ° C., so the temperature of the appearance product after being vacuum molded and carried into the Styrofoam molding machine is 80 ° C. or higher. Therefore, it was not necessary to heat the appearance product before filling the styrofoam raw material into the mold, and the molding could be performed with a small energy.

[0026]

According to the present invention, a plate-shaped thermoplastic synthetic resin sheet is stretched and held on a clamp frame, heated and softened by a heating means, and then the heat-softened sheet is placed on a molding die to form the sheet. After the primary processing of forming a mold by bringing the mold into close contact with a molding die by air or vacuum suction means, the molding die holding the molded sheet is used to form a foamed resin layer. , Closed with another mold for forming a foamed resin layer, filled with foamed resin raw material in the mold, heated and foamed, integrally laminated and welded the foamed resin layer to the sheet, and cooled to form a molded product. After the secondary processing, the molded product is released from the molding die and taken out consistently, so that the process from plastic sheet molding to foamed resin layer molding is performed consistently, and correction of the molding die Omit the process and use foam resin It is possible to produce a plastic molded article having a foamed resin layer having a proper formability less energy without having to heat by continuously and efficiently fast appearance products before filling into Katachikin inner mold. Further, in the present invention, a clamp frame that stretches and holds a plate-shaped synthetic resin sheet is slidably provided on the traveling rail, and a heating mechanism and one of the foamed resin layer forming dies can be provided in the sheet traveling path of the traveling rail. A primary working mold, and a pressurized or vacuum forming mechanism capable of disposing the forming mold, on a pedestal that can be raised and lowered so that the primary working mold can be pressed and held on the sheet heated and softened by the heating mechanism. In addition, the foamed resin layer molding die is provided so as to be able to run on a transport rail, and is further transferred to the end of the transport rail at the foamed resin layer molding position to form one foamed resin layer molding die. The other foamed resin layer molding die is set up and down with respect to the resin layer molding die so as to be movable up and down, and the other foamed resin layer molding die and one of the foamed resin layer molding dies transferred immediately below. With a foamed resin layer forming mechanism With this, it is possible to efficiently produce a plastic molded product integrally having a foamed resin layer having excellent appearance quality without leaving any distortion in the foamed resin layer, reducing the number of work steps and reducing the cost suitable for mass production. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is an overall side view of a manufacturing apparatus showing an embodiment of the present invention.

FIG. 2 is a front view of the example of FIG.

FIG. 3 is a system explanatory diagram of the example of FIG. 1;

FIG. 4 is a longitudinal sectional view of a plastic molded article having a foamed resin layer manufactured in the example of FIG.

FIG. 5 is a longitudinal sectional view of a vacuum forming mechanism used in the example of FIG.

FIG. 6 is a longitudinal sectional view of a foaming resin layer forming mechanism used in the example of FIG. 1 in a mold separating state.

FIG. 7 is a longitudinal sectional view showing an operation state of the example of FIG. 6 at the time of mold clamping.

[Explanation of symbols]

Reference Signs List A resin sheet B foam resin layer C plastic molded article 1 running rail 2 clamp frame 3 heater 4 ₁ primary processing mold 4 foam resin layer mold (lower mold) 5 foam resin layer mold (upper mold) Reference Signs List 6 vacuum forming mechanism 7 gantry 8 lift cylinder 9 transfer rail 10 foam resin layer forming mechanism 11 raw material supply mechanism 12 trimming finishing mechanism 13 turret 14,15 cylinder 16 frame 18 bolster cylinder 19 bolster 21 vacuum device 25 cylinder 26 diver 27 vacuum device

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shoji Tokaibayashi 10 331 Miyakazo, Shizuoka City, Shizuoka Pref. Seki Manufacturing Co., Ltd. (Ref.)

Claims (3)

[Claims] 1. A sheet-shaped thermoplastic synthetic resin sheet is stretched and held on a clamp frame and heated and softened by a heating means. Then, the heat-softened sheet is placed on a forming die, and the sheet is formed on a forming die. After the primary processing of forming the mold in close contact with the mold with compressed air or vacuum suction means, using the forming mold holding the formed sheet as one of the foaming resin layer forming molds for forming the foaming resin layer, Close the mold with another mold for forming the foamed resin layer, fill the mold with the foamed resin raw material, heat and foam, integrally laminate and weld the foamed resin layer to the sheet, and cool to form a molded product. A method of manufacturing a plastic molded article having a foamed resin layer, wherein after the next processing, the molded article is released from a molding die and taken out consistently. 2. A traveling frame is provided with a clamp frame which stretches and holds a plate-shaped synthetic resin sheet, and can be used as a heating mechanism and a mold for forming one foamed resin layer in a sheet traveling path of the traveling rail. A primary working mold, and a pressurized or vacuum forming mechanism capable of disposing the forming mold, on a pedestal that can be raised and lowered so that the primary working mold can be pressed and held on the sheet heated and softened by the heating mechanism. In addition, the foamed resin layer molding die is provided so as to be able to run on a transport rail,
Further, the foamed resin layer is transferred to the end of the conveying rail at the foamed resin layer molding position, and is used as one foamed resin layer molding die. A plastic molded article having a foamed resin layer, characterized in that it is provided as a foamed resin layer molding mechanism with the other foamed resin layer molding die and one of the foamed resin layer molding dies transferred directly below. manufacturing device. 3. A tool rest having a blade body for punching out and cutting an outer peripheral portion of the softened sheet pressed by the primary working mold is provided between the vacuum forming mechanism and the foamed resin layer forming mechanism. 2. A transfer rail circulating through a molded product take-out position in order from a vacuum forming position to a foamed resin layer forming position via a trimming position and a trimming finishing mechanism, and a transfer rail is provided. An apparatus for manufacturing a plastic molded article having a foamed resin layer.