JP6751504B2 - Molding method of resin molded products and molding equipment for thermoplastic resin - Google Patents

Description

The present invention relates to a method for molding a resin molded product and a molding apparatus, and more specifically, a method for molding a resin molded product using a thermoplastic resin that is extruded downward by primary molding in a hanging form and molded by secondary molding. And molding equipment.

Conventionally, for example, in order to manufacture a resin sandwich panel, a molding method that combines primary molding by extrusion and secondary molding by blow (or vacuum) has been used. According to such a molding method, the extruded molten resin is used as it is for blow (or vacuum) molding, so that the once molded resin is reheated, resulting in non-uniformity of heating and the like. It is possible to form a sandwich panel without causing any technical problems.
In particular, as compared with the case where the extruded molten resin is hung downward as it is, the resin extending in the vertical direction is molded, and blow (or vacuum) formed, for example, the resin is extruded in the lateral direction. It is possible to feed the molten resin from the extrusion die in a non-contact state without having to support the molten resin until the molding of the secondary molding.

However, in these preceding molding techniques, due to the drawdown or neck-in that occurs in the molten sheet due to the molten resin extruded before the secondary molding being drooped downward as it is, the sheet Since a technical problem is caused in which the sheet thickness before molding by the mold becomes non-uniform in the extrusion direction or the width direction, the applicant proposes the following new molding technology in Patent Document 1. doing. Here, the drawdown is a phenomenon in which the molten sheet is stretched by the weight of the sheet over time and becomes thinner toward the upper part of the sheet. By the way, the neck-in is the width direction of the sheet due to the drawdown. It is a phenomenon that the seat width becomes smaller due to shrinkage.
That is, the molding method of this resin molded product includes a step of extruding the thermoplastic resin downward so as to hang down in the form of a molten sheet, and a method of extruding the molten sheet resin downward by a pair of rollers. The stage of sandwiching and feeding downward by the rotational drive of the roller, the stage of arranging the molten sheet-like resin sent downward to the side of the mold arranged below the pair of rollers, and the molten sheet-like It has a step of depressurizing the sealed space formed between the resin and the mold and / or pressing the sheet-shaped resin toward the mold to form a shape along the mold shape, particularly. After the lowermost part of the molten sheet-like resin extruded downward passes between the pair of rollers, the sheet-like resin is sandwiched between the pair of rollers by bringing the pair of rollers relatively close to each other. It is driven downward by rotational drive at a speed higher than the predetermined extrusion speed.

According to the molding method of such a resin molded product, as the sheet-shaped resin is fed downward by the pair of rollers, the length of the sheet-shaped resin that hangs down in the vertical direction becomes longer, and the sheet-like resin that hangs down due to this becomes longer. The upper part of the resin is thinned by the weight of the sheet resin (drawdown or neck-in), while the rotation speed of the rollers is adjusted so that the delivery speed of the pair of rollers is equal to or higher than the extrusion speed. The sheet-shaped resin is pulled downward by a pair of rollers so as to be stretched and thinned.
At this time, the rotation speed of the roller is reduced with the passage of time, and the delivery speed is adjusted so as to be close to the extrusion speed of the thermoplastic resin sheet. As a result, the downward pulling force of the pair of rollers decreases toward the upper part of the sheet-shaped resin, so that the stretch thinning due to such pulling force is relatively reduced, and the thinning due to drawdown or neck-in is reduced. It is possible to effectively prevent drawdown or neck-in, thereby forming a uniform thickness in the extrusion direction.
Next, a sheet-shaped resin having a uniform thickness in the extrusion direction is arranged on the side of the mold arranged below the pair of rollers, and a closed space formed between the sheet-shaped resin and the mold. By reducing the pressure and / or pressurizing the sheet-like resin toward the mold to form a shape that follows the shape of the mold, in the extrusion direction without adversely affecting the shaping during secondary molding. It is possible to mold a resin molded product having a desired thickness.

However, the applicant has found that in this molding method, the following new technical problems are caused by adjusting the thickness of the sheet-like resin in the molten state exclusively by a pair of rollers. I found.
First, if an attempt is made to thin the molten resin sheet only by feeding out the molten resin sheet by a pair of rollers, the rotation speed of the pair of rollers, that is, depending on the adjustment of the feeding speed, is accompanied by the progress of feeding. There is a limit to the suppression of drawdown caused by the own weight of the resin sheet, and the resin sheet sent out from the pair of rollers can be thinned only within the range considering that it is stretched by its own weight without being adjusted thereafter. That is, the melted resin sheet may be torn off depending on the length (weight) of the molten resin sheet hanging from the pair of rollers, so it is necessary to determine the thickness of the resin sheet within a range in consideration of drawdown. was there. Further, in order to thin the sheet-like resin in the molten state, if the rotation speed of the pair of rollers is increased to increase the delivery speed of the sheet-like resin, the drawdown along the delivery direction of the sheet-like resin is suppressed. Even if it is possible, neck-in occurs in the width direction in the direction orthogonal to the feeding direction of the sheet-shaped resin, which makes it difficult to achieve further thinning or adversely affects the secondary molding.
Secondly, the molten sheet-like resin continuously fed by the pair of rollers cools the surface of the sheet-like resin by contact with the rollers at room temperature, which adversely affects the moldability during secondary molding. It is a point. More specifically, the sheet-like resin is delivered by the rotational drive of the rollers through the line contact between the sheet surface of the molten sheet-like resin and the outer peripheral surfaces of the pair of rollers, and the sheet-like resin is melted during this line contact time. The sheet surface of the sheet-like resin in the state is cooled, which becomes an obstacle to shaping by the mold during secondary molding. However, if the rotation speed of the roller is increased in order to shorten the line contact time, neck-in occurs as in the first case, and depending on the pressing force of the roller against the sheet-like resin, the roller and the sheet-like resin Excessive slippage may occur between the resin and the sheet, which may hinder the smooth delivery of the sheet-like resin.

In this regard, Patent Document 2 discloses a technique of towing the lowermost portion of the molten sheet-like resin while feeding out the molten sheet-like resin by a pair of rollers.
More specifically, one sheet is extruded from each of at least two dies connected to the extruder, and immediately after this, each sheet is sandwiched by a pair of sandwiching rollers, and at least the surface of each sheet is heated. Wrinkles are smoothed, gloss is applied, at least two glossed sheets are towed and supplied into a blow molding die, the blow molding die is closed, the two sheets are bonded together, and blow molding is performed. To disclose.
More specifically, by controlling the towing speed of the sheets or adjusting the screw rotation speed of the extruder according to the drawdown of each sheet, both glossy sheets are molded at almost the same time. It is made to be supplied inside.
However, Patent Document 2 discloses that the towing speed of the sheets is controlled or the screw rotation speed of the extruder is adjusted according to the drawdown of each sheet, which is the draw of each sheet. By controlling the towing speed of the sheets or adjusting the screw rotation speed of the extruder on the premise that drawdown will occur on both sheets, rather than suppressing or eliminating the occurrence of down, both sheets can be made. It is only supplied into the molding mold at almost the same time.

From the above, in Patent Document 1, the thickness of the molten sheet-like resin is adjusted exclusively by a pair of rollers, whereas in Patent Document 2, a pair of rollers and a clamp are used in combination to adjust the thickness of the molten sheet. Although the resin is fed by a pair of rollers and towed by a clamp, the pair of rollers does not adjust the thickness of the molten sheet resin, but mirrors or glosses the sheet surface. The towing of the sheets merely causes both the glossed sheets to be supplied into the molding die at almost the same time, and neither of them is involved in adjusting the thickness of the molten sheet-like resin.

In this regard, if a resin having a relatively large MFR value or melt tension value is used as the resin used for the sheet, such drawdown or neck-in can be prevented to some extent, but it becomes a limitation of the materials that can be used. It is not practical. In particular, when molding a thin-walled sheet, it is preferable that the MFR value is large, so that the limitation of the MFR value may not be sufficient.

In view of the above technical problems, an object of the present invention is a molding method and molding of a resin molded product capable of ensuring good moldability while enabling thinning without imposing restrictions on the type of resin to be adopted. To provide the equipment.
Japanese Patent No. 4902789 Japanese Unexamined Patent Publication No. 11-5248

In order to achieve the above object, the method for molding a resin molded product according to the present invention is:
The stage of extruding the thermoplastic resin at a predetermined extrusion speed so that it hangs down like a molten sheet, and
The stage of towing the molten sheet-like resin that is extruded downward at a towing speed higher than the extrusion speed, and
The stage of arranging the towed molten sheet resin on the side of the mold, and
A step of decompressing the closed space formed between the molten sheet-shaped resin and the mold and / or pressing the sheet-shaped resin toward the mold to form a shape along the mold shape. It has a structure.

In the towing step, it is preferable to reduce the towing speed over time. Further, in the towing stage, it is preferable to gradually reduce the towing speed with the passage of time.

The towing step includes a step of clamping the lowermost portion of the molten sheet-like resin extruded downward.
It has a step of towing the bottom of the clamped sheet resin downward,
The towing step is performed between the clamp start position at the bottom of the molten sheet resin and the clamp release position at the bottom of the melted sheet resin at a level below the clamp start position.
The clamp start position is set to a level between the extrusion start position and the mold, and the clamp release position is set to a level below the mold.
The clamp start level and clamp release level of the molten sheet resin are determined according to the length of the cavity along the extrusion direction of the cavity, which is determined according to the dimensions of the molded product. , It is better to determine the towing speed of the clamp device.

Further, it is preferable to have a step of adjusting the towing speed and / or the towing time according to a desired thickness of the sheet-like resin in a molten state in the step of arranging the mold laterally.

The towing time adjustment step may include a step of adjusting the level of the clamp start position and / or the clamp release position.

Initial towing downward in relation to the melt index of the molten sheet resin according to the difference between the thickness immediately after extruding the molten sheet resin and the target thickness immediately before being molded by the mold. It is good to set the towing speed.

The thermoplastic resin may contain 5 to 40 parts by weight of an inorganic filler in one or more types of polyolefin resin, and the melt index of the thermoplastic resin at 230 ° C. may be 1.0 to 3.0 g / 10 min. preferable.

Further, the first and second molten sheet-shaped resins are arranged between the split dies, and the air between one die of the split dies and the first sheet-shaped resin is depressurized to reduce the pressure of the first sheet. The mold resin is brought into close contact with one mold cavity, and the air between the other mold of the split mold and the second sheet resin is depressurized so that the second sheet resin is brought into close contact with the other mold cavity. After that, it has a stage to mold the split mold,
A resin molded product may be molded by welding and integrating the first and second sheet-shaped resins through the pinch-off forming portion on the outer periphery of the mold by mold clamping of the split mold. The resin molded product to be molded has, for example, a closed hollow portion.

Further, it may have a configuration in which a clamp portion for clamping the first sheet-shaped resin and a clamp portion for clamping the second sheet-shaped resin are provided, and the pair of clamp portions are synchronized with each other.

Further, in order to achieve the above object, the molding apparatus for the resin molded product according to the present invention may be used.
The thermoplastic resin is shaped by extrusion molding, and the primary molding part that extrudes the primary molded thermoplastic resin in a hanging form and the thermoplastic resin extruded by the primary molding part are secondary molded by blow molding or vacuum forming. In a thermoplastic resin molding apparatus having a secondary molding portion,
The primary molding part is
Melt-kneading means for melt-kneading thermoplastic resin,
A storage means for storing a predetermined amount of melt-kneaded thermoplastic resin,
It has an extrusion slit that intermittently extrudes the stored thermoplastic resin so as to hang down in the form of a molten sheet.
The secondary molding part is
A pair of split dies that are movable in a direction substantially orthogonal to the sheet surface between the open position and the closed position with the hanging sheet-like resin sandwiched between them and have cavities formed on the surfaces facing each other.
It has a mold moving means for moving a pair of split molds in a direction substantially orthogonal to the sheet surface between the open position and the closed position.
Further, a clamp portion capable of clamping the lowermost portion of the sheet-like resin extruded downward, a clamp portion moving means for moving the clamp portion in the vertical direction, and a clamp portion moving means for moving the clamp portion in the vertical direction. It has a clamp portion moving speed adjusting means for adjusting the moving speed, and a sheet-like resin towing means provided with the clamp portion moving speed adjusting means.
The clamp portion moving speed adjusting means adjusts the moving speed of the clamp portion so as to tow the molten sheet-like resin extruded downward at a towing speed equal to or higher than the extrusion speed.
It is characterized by that.

The clamp portion moving speed adjusting means preferably reduces the towing speed with the passage of time.

Further, it is preferable that the clamp portion extends over a predetermined length so that a molten sheet resin having a predetermined width in a direction orthogonal to the extrusion direction can be clamped.

Further, the first and second molten sheet-shaped resins are arranged between the split dies, and the air between one of the split dies and the first sheet-shaped resin is depressurized to reduce the pressure of the first sheet. The second sheet resin is brought into close contact with the other mold cavity by reducing the air pressure between the other mold of the split mold and the second sheet resin while bringing the resin into close contact with one mold cavity. After that, the split mold is molded, and the resin molded product is molded by welding and integrating the first and second sheet-shaped resins through the pinch-off forming portion on the outer periphery of the mold by mold clamping of the split mold. It is a molding device for molded products.
A configuration may be configured in which a clamp portion for clamping the first sheet-shaped resin and a clamp portion for clamping the second sheet-shaped resin are provided, and the pair of clamp portions are synchronized with each other.

A first embodiment of a molding apparatus for a resin molded product according to the present invention will be described in detail below with reference to the drawings.
In this embodiment, a single sheet-shaped molded product is targeted as the resin molded product.
As shown in FIG. 1, the molding device 10 of a resin molded product has an extrusion device 12 and a mold clamping device 14 arranged below the extrusion device 12, and is a sheet in a molten state extruded from the extrusion device 12. The resin is sent to the mold clamping device 14, and the sheet-shaped resin in a molten state is molded by the mold clamping device 14.

The extrusion device 12 is a conventionally known type, and although detailed description thereof will be omitted, a cylinder 18 to which the hopper 16 is attached, a screw (not shown) provided in the cylinder 18, and a screw are connected to the extrusion device 12. It has a hydraulic motor 20, an accumulator 24 in which the cylinder 18 and the inside communicate with each other, and a plunger 26 provided in the accumulator 24. Resin pellets thrown in from the hopper 16 are screwed by the hydraulic motor 20 in the cylinder 18. The molten resin is melted and kneaded by the rotation of the hydraulic pressure, and the molten resin is transferred to the accumulator 24 chamber and stored in a certain amount, and the molten resin is sent toward the T die 28 by the drive of the plunger 26, and the continuous sheet is passed through the extrusion slit 34. The accumulator is extruded and is fed downward while being sandwiched by a pair of rollers 30 arranged at intervals, and is hung between the split molds 32. As a result, as will be described in detail later, the sheet-like resin is arranged between the split dies 32 in a state where the sheet-like resin has a uniform thickness in the vertical direction (extrusion direction).

The extrusion capacity of the extrusion device 12 is appropriately selected from the viewpoints of the size of the resin molded product to be molded, the drawdown of the sheet-shaped resin, or the prevention of neck-in occurrence. More specifically, from a practical point of view, the extrusion amount of one shot in intermittent extrusion is preferably 1 to 10 kg, and the extrusion rate of the resin from the extrusion slit 34 is several hundred kg / hour or more, more preferably. It is 700 kg / hour or more. Further, from the viewpoint of preventing drawdown or neck-in of the sheet-shaped resin, the extrusion process of the sheet-shaped resin is preferably as short as possible, and depends on the type of resin, the MFR value, and the melt tension value, but is generally extruded. The process should be completed within 40 seconds, more preferably within 10-20 seconds. Therefore, the unit area of the thermoplastic resin from the extrusion slit 34 and the extrusion amount per unit time are 50 kg / hour cm ² or more, more preferably 150 kg / hour cm ² or more. For example, from an extruded slit 34 of a T-die 28 having a slit spacing of 0.5 mm and a length of 1000 mm in the width direction of the slit, a thermoplastic resin having a density of 0.9 g / cm ³ is used to make a thickness of 1.0 mm and a width of 1000 mm. When extruding as a sheet-like resin with a length of 2000 mm in the extrusion direction in 15 seconds, 1.8 kg of thermoplastic resin is extruded in 15 seconds per shot, and the extrusion speed is 432 kg / hour, which is per unit area. The extrusion rate can be calculated to be about 86 kg / hour cm ² .

As will be described later, the rotation of the pair of rollers 30 causes the sheet-like resin sandwiched between the pair of rollers 30 to be sent downward, and the lower end of the sheet-like resin is driven downward by the clamp portion 304 of the clamping device 300. By towing downward, the sheet-like resin can be stretched and thinned, and the relationship between the extrusion speed of the extruded sheet-like resin and the delivery speed of the sheet-like resin by the pair of rollers 30 and the delivery of the sheet-like resin. By adjusting the relationship between the speed and the downward towing speed of the clamp portion, it is possible to prevent the occurrence of drawdown or neck-in, so the type of resin, especially the MFR value and melt tension value, or unit. It is possible to reduce the constraint on the amount of extrusion per hour.

As shown in FIG. 1, the extrusion slit 34 provided in the T-die 28 is arranged vertically downward, and the continuous sheet-shaped parison extruded from the extrusion slit 34 hangs vertically downward from the extrusion slit 34 as it is. I am trying to send it to. As will be described later, the thickness of the sheet-shaped resin of the extruded slit 34 can be changed by changing the interval thereof.

As shown in FIG. 2 (in FIG. 2, the left side in the drawing is downward in FIG. 1), the main body of the T-die 28 has a die 38a having a die lip 36a at the tip and a die 38b having a die lip 36b at the tip. The slit gap adjusting device 42 and the slit gap driving device 44 are provided to adjust the spacing between the extrusion slits 34 by forming the spacing between the die lips 36a and 36b by overlapping the die lips 36a and 36b. Recessed grooves 56a and 56b are provided in the vicinity of the die lip 36a and the die lip 36b, respectively, so that the die lip 36a and the die lip 36b are easily bent in the vertical direction on the drawing, and thus the slit gap adjusting device 42 and the slit gap driving device 44 respectively. , The spacing between the extrusion slits 34 is adjusted. Both the slit gap adjusting device 42 and the slit gap driving device 44 have known configurations, but the slit gap adjusting device 42 deforms the die lip 36a to make the thickness uniform in the width direction of the sheet (from the back to the front of the drawing). The slit gap driving device 44 functions to adjust the property, while the slit gap driving device 44 functions to deform the die lip 36b to adjust the thickness of the sheet in the extrusion direction (left-right direction in the drawing), and is supplied to the T-die 28. The thermoplastic resin is extruded as a sheet from the manifold of the main body of the T-die 28 shown in FIG. 2 through the resin flow path 33 and from the extrusion slit 34.

The slit clearance adjusting device 42 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 42 are arranged at equal intervals along the width direction of the extrusion slits 34, and the slit gap A is narrowed or widened by each slit gap adjusting device 42 to reduce the thickness of the sheet in the width direction. To be uniform.

Each slit clearance adjusting device 42 is composed of a die bolt 46, an adjusting shaft 50 connected to the die bolt 46, and an engaging piece 54 connected to the adjusting shaft 50 via a fastening bolt 52, and the die bolt 46 and the adjusting shaft. The 50 and the engaging piece 54 are provided so as to straddle the recessed groove 56a. More specifically, the slit clearance adjusting device 42 has a die bolt 46 provided so as to be able to advance and retreat toward one die lip 36a, and an adjusting shaft 50 is arranged at the tip thereof via a pressure transmitting portion. An engaging piece 54 is connected to the adjusting shaft 50 by a fastening bolt 52, and the engaging piece 54 is connected to one of the die lips 36a. When the die bolt 46 is advanced, the adjusting shaft 50 is extruded toward the tip via the pressure transmitting portion, and one die lip 36a is pressed. As a result, the die lip 36a is deformed at the portion of the concave groove 56a, and the slit gap A is narrowed. To widen the slit gap A, the die bolt is retracted on the contrary.

Further, the slit gap A 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 50 with an electric heater (not shown) and thermally expanding it, one of the die lips 36a is pressed and the slit gap A is narrowed. Further, in order to widen the slit gap A, the electric heater is stopped, and the adjusting shaft 50 is cooled and contracted by a cooling means (not shown).

On the other hand, the slit gap driving device 44 includes a sliding bar 58 and a driving piece 60. The sliding bar 58 is arranged in the sliding groove 62 and is moved in the width direction of the slit by a driving means described later. The drive piece 60 is connected to the other die lip 36b. When the sliding bar 58 advances and retreats in the width direction of the slit, the drive piece 60 pushes and pulls the other die lip 36b in conjunction with this. As a result, the die lip 36b can be deformed at the portion of the concave groove 56b to change the slit gap A.

It is preferable that the sheet extruded from the T-die 28 is adjusted so that the thickness in the extrusion direction becomes uniform in a state of being hung between the split dies 32, that is, at the time of molding. In this case, the slit gap A is gradually widened from the start of extrusion and varied so as to be maximum at the end of extrusion. As a result, the thickness of the sheet extruded from the T-die 28 gradually increases from the start of extrusion, but the sheet extruded in the molten state is stretched by its own weight and gradually becomes thinner from the lower side to the upper side of the sheet. It is possible to adjust the thickness from the upper side to the lower side of the sheet by canceling the portion that is expanded and extruded thickly and the portion that is stretched and thinned by the drawdown phenomenon.

Explaining the pair of rollers 30 with reference to FIG. 3, in the pair of rollers 30, each rotation axis is arranged substantially horizontally in parallel with each other below the extrusion slit 34, and one of them is a rotation drive roller 30A. Yes, the other is the rotated drive roller 30B. More specifically, as shown in FIG. 1, the pair of rollers 30 are arranged so as to be line-symmetric with respect to the sheet-shaped resin extruded in a form of hanging downward from the extrusion slit 34.
The diameter of each roller and the axial length of the rollers may be appropriately set according to the extrusion speed of the sheet-shaped resin to be molded, the extrusion direction length and width of the sheet, the type of resin, and the like, which will be described later. The diameter of the rotary drive roller 30A is the diameter of the rotated drive roller 30B from the viewpoint of smoothly feeding the sheet resin downward by the rotation of the rollers with the sheet resin sandwiched between the pair of rollers 30. It is preferably slightly larger. The diameter of the roller is preferably in the range of 50 to 300 mm, and if the curvature of the roller is too large or too small in contact with the sheet-shaped parison, it causes a problem that the sheet-shaped parison winds around the roller.

The rotary drive roller 30A is provided with a roller rotary drive means 94 and a roller moving means 96, and the roller rotary drive means 94 makes the rotary drive roller 30A rotatable about its axial direction, while the roller moving means 96. As a result, the rotary drive roller 30A approaches the rotary drive roller 30B or approaches the rotary drive roller 30B while maintaining a parallel positional relationship with the rotary drive roller 30B in a plane including the pair of rollers 30. I try to move away from.

More specifically, the roller rotation drive means 94 is a rotation drive motor 98 connected to the rotation drive roller 30A, and the rotation torque of the rotation drive motor 98 is applied to the rotation drive roller 30A via, for example, a gear reduction mechanism (not shown). I try to convey it to. The rotation drive motor 98 is conventionally known, and a rotation speed adjusting device 100 is attached so that the rotation speed can be adjusted. The rotation speed adjusting device 100 may adjust the current value for the electric motor, for example, and as will be described later, the sheet-like resin is extruded from the extrusion slit 34 and the sheet-like shape is formed by the rotation of the pair of rollers 30. The relative speed difference from the feeding speed at which the resin is fed downward is adjusted according to the extrusion speed of the sheet-shaped resin. The feeding speed of the sheet-shaped resin by the rollers is, for example, when a pair of rollers having a diameter of 100 mm is used to feed the sheet-shaped resin having a length of 2000 mm in the feeding direction in 15 seconds, the speed is about 6.4 rotations in 15 seconds per shot. Therefore, the rotation speed of the roller can be calculated to be about 25.5 rpm. By increasing or decreasing the rotation speed of the roller, the feeding speed of the sheet-like resin, which is the sheet-like resin, can be easily adjusted.

As shown in FIG. 4, the rotated drive roller 30B rotates about the rotation axis of the roller over the end peripheral surface 102 so that the rotated drive roller 30B is rotationally driven in synchronization with the rotary drive roller 30A. The rotary drive roller 30A has a possible first gear 104, while the rotary drive roller 30A has a second gear 108 that meshes with the first gear 104 that is rotatable about the axis of rotation of the roller over its end peripheral surface 106.
As shown in FIG. 3, the roller moving means 96 includes a piston-cylinder mechanism 97, and the tip of the piston rod 109 is connected to a cover 111 that rotatably supports the rotary drive roller 30A in the axial direction thereof, for example, pneumatic pressure. By adjusting the above, the piston 113 is slid with respect to the cylinder 115, whereby the rotary drive roller 30A is moved in the horizontal direction, so that the distance between the pair of rollers 30 can be adjusted. In this case, as will be described later, before the lowermost portion of the sheet-shaped resin is supplied between the pair of rollers 30, the distance between the pair of rollers 30 is widened from the thickness of the supplied sheet-shaped resin (FIG. 3 (A), the open position constituting the interval D1), so that the sheet-like resin is smoothly supplied between the pair of rollers 30, and then the interval between the pair of rollers 30 is narrowed so that the pair of rollers 30 The sheet-shaped resin is sandwiched (closed position forming the interval D2 in FIG. 3A), and the sheet-shaped resin is fed downward by the rotation of the roller. The stroke of the piston 113 may be set so as to be the distance between the open position and the closed position. Further, by adjusting the air pressure, it is also possible to adjust the pressing force acting on the sheet-shaped resin from the rollers when the sheet-shaped resin passes between the pair of rollers 30. In the range of pressing force, the rotation of the pair of rollers 30 does not cause slippage between the surface of the pair of rollers 30 and the surface of the sheet-like resin, while the pair of rollers 30 tears off the sheet-like resin. It is determined that the sheet-like resin is surely sent downward so as not to occur, and it is, for example, 0.05 MPa to 6 MPa, depending on the type of resin.
Further, when the molten sheet-like resin is stretched between the extrusion slit 34 and the pair of rollers 30 by the pair of rollers 30, the extrusion slit 34 is provided so that the molten sheet-like resin is not torn off during stretching. It is preferable to adjust the level difference between the pair of rollers 30.

The rotary drive roller 30A has a helical shape that is oriented so as to guide the sheet resin toward each end of the rotary drive roller 30A when the sheet resin is sent downward by the rotation of the pair of rollers 30. A pair of shallow grooves 112 are provided over the outer peripheral surface thereof. As a result, the sheet-like resin passes through the pair of rollers 30, so that the sheet-like resin can be stretched in a direction to widen the width. The pitch and depth of the shallow groove 112 may be appropriately set according to the material of the sheet-shaped resin, the rotation speed of the roller to be set, and the like. By the way, the pitch of the shallow groove in FIG. 4 is exaggerated for easy understanding.
The rotary drive roller 30A may be provided with a surface temperature adjusting means for adjusting the surface temperature of the roller according to the temperature of the sheet-shaped resin. For example, the structure is such that a refrigerant is passed through the inside of the roller. By circulating the refrigerant, heat exchange may be performed so that the surface of the rollers is not excessively heated by the sheet-like resin in the molten state sandwiched between the pair of rollers 30. The outer peripheral surface of the roller should be heat-resistant coated.

As shown in FIG. 1, the clamp device 300 has a clamp portion 304, an arm portion 302 provided with the clamp portion 304 at one end, and an arm drive portion 304 provided at the other end of the arm portion 302.
The clamp portion 304 has a pair of clamp portions 304 that can rotate between a clamp position and a clamp release position about a pin 303 provided at one end of the arm portion 302, and each of the pair of clamp portions 304 has a pair of clamp portions 304. A molten sheet-like resin having a predetermined width in a direction orthogonal to the extrusion direction is extended over a predetermined length (vertical direction in the drawing) so that it can be clamped. When towing the molten sheet resin downward in a clamped state, the tips of the pair of clamp portions 304 are in a molten state so that slip does not occur between the pair of clamp portions 304 and the sheet resin. It is preferable to provide a claw portion that can bite into the sheet-shaped resin.

The arm portion 302 can be expanded and contracted in the vertical direction between the clamp start level (PH) and the clamp release level (PL) by the arm drive portion 304, and the vertical direction of the arm portion 302 is melted between the split molds. It is positioned so as to coincide with the extrusion direction of the sheet-like resin in the state, and at the clamp start level (PH), the lower end of the molten sheet sent out by the pair of rollers is clamped, and the clamped state is clamped. It descends to the release level (PL), where the clamp is released.
The clamp start level (PH) is provided between the pair of rollers and the upper end of the split die, and the clamp release level (PL) is provided below the lower end of the split die, thereby causing the split die. When the mold is closed from the mold opening, interference is prevented. With the split mold open, the arm portion 302 extends to the clamp start level (PH) and the arm portion 302 lowers to the clamp release level (PL). By doing so, it is possible to clamp the split mold in a state where the molten sheet-like resin is arranged between the split molds.

By adjusting the amount of expansion and contraction of the arm unit 302 by the arm drive unit 304, the clamp start level (PH) and the clamp release level (PL) can be adjusted independently of each other. For example, the clamp device 300 can tow the molten sheet. The level difference between the clamp start level (PH) and the clamp release level (PL) may be determined in relation to the towing speed of the arm drive unit 304 according to the amount of thinning.
The clamp start level (PH) and clamp release level (PL) of the molten sheet resin are determined according to the length of the cavity 116 along the extrusion direction of the sheet resin, which is determined according to the dimensions of the molded product. The towing speed of the clamp device 30 may be determined accordingly.
The arm drive unit 304 makes the arm unit 302 movable in the vertical direction between the clamp start level (PH) and the clamp release level (PL), and at that time, the vertical movement speed of the arm unit 302, that is, the clamp unit. The towing speed of the sheet-like resin in the molten state clamped by 304 can be adjusted. Specifically, the arm drive unit 304 is connected to the ball screw, and the position and moving speed of the arm unit 302 are controlled by the rotation of the ball screw. When towing each of the two molten sheet-like resins with the corresponding clamp device 300, the two molten sheet-like resins are simultaneously arranged between the split molds, and one sheet-like resin stands by. It is preferable to synchronize the arm drive unit 304 of the clamp device 300 so that the state does not occur.
A clamp portion moving speed adjusting means (not shown) is provided, and the towing speed of the sheet-shaped resin by the clamp portion moving speed adjusting means is equal to or higher than the sending speed according to the feeding speed of the thermoplastic sheet-shaped resin by the pair of rollers 30. A speed difference setting means (not shown) is provided that adjusts the moving speed of the clamp portion within the above range and sets the speed difference between the towing speed and the feeding speed to be equal to or less than the speed difference between the feeding speed and the predetermined extrusion speed. Be done.

On the other hand, the mold clamping device 14 is also a conventionally known type like the extrusion device 12, and although detailed description thereof will be omitted, the two divided molds 32A and B and the molds 32A and B are in a molten state. It has a mold driving device for moving between an open position and a closed position in a direction substantially orthogonal to the supply direction of the sheet-shaped resin.

As shown in FIG. 1, the two divided molds 32A and B are arranged with the cavities 116 facing each other, and the cavities 116 are arranged so as to face substantially the vertical direction. On the surface of each cavity 116, uneven portions are provided according to the outer shape and surface shape of the molded product molded based on the molten sheet-like resin. In each of the two divided molds 32A and B, a pinch-off portion 118 is formed around the cavity 116, and the pinch-off portion 118 is formed in an annular shape around the cavity 116 and faces the molds 32A and B. Protrude toward. As a result, when the two split molds 32A and B are molded, the tips of the pinch-off portions 118 are brought into contact with each other so that the parting line PL is formed on the peripheral edge of the molten sheet-like resin. ing.
When molding a single sheet-shaped resin molded product, a single mold is used as an alternative to molding the molds together using a split mold, and the mold is placed on the side of the mold. Placing the extruded sheet-like resin and depressurizing the sealed space formed between the sheet-like resin and the mold without molding, and / or pressurizing the sheet-like resin toward the mold. It may be formed into a shape that follows the shape of the mold.

The molds 33A and B are slidably fitted on the outer periphery of each of the two split molds 32A and B, and the molds 33A and B are respectively molded with respect to the mold moving device (not shown). It is movable relative to the molds 32A and B. More specifically, the mold 33A can come into contact with one side surface of the sheet-shaped resin arranged between the molds 32A and B by projecting toward the mold 32B with respect to the mold 32A. By projecting toward the mold 32A with respect to the mold 32B, the mold 33B can come into contact with the other side surface of the sheet-shaped resin arranged between the molds 32A and B.

The mold drive device is the same as the conventional one, and the description thereof will be omitted. However, the molds 32A and B of the two split types are each driven by the mold drive device, and are split into two at the open position. A sheet-like resin in a molten state can be arranged between the molds 32A and B, while the pinch-off portions 118 of the two split molds 32A and B abut at the closed position, and the annular pinch-off portion 118 is formed. By abutting against each other, a closed space is formed in the two split dies 32A and B. Regarding the movement of the molds 32A and B from the open position to the closed position, the closed position is set to the position of the center line of the sheet-like resin in the molten state, and the molds 32A and B are driven by the mold drive device. I try to move toward that position.

As shown in FIG. 7, a vacuum suction chamber 120 is provided inside one of the split molds 32, and the vacuum suction chamber 120 communicates with the cavity 116 through the suction hole 122, and the suction hole from the vacuum suction chamber 120. By sucking through the cavity 116, the sheet-like resin is attracted toward the cavity 116 so as to be shaped along the outer surface of the cavity 116.

The sheet-like resin is made of a sheet formed of polypropylene, engineering plastics, olefin-based resin, or the like. More specifically, as the sheet-shaped resin, it is preferable to use a resin material having a high melt tension from the viewpoint of preventing the thickness from being varied due to drawdown, neck-in, etc., while transferability to the mold is preferable. It is preferable to use a resin material having high fluidity in order to improve the followability.
Specifically, it is a polyolefin (for example, polypropylene, high-density polyethylene) which is a homopolymer or copolymer of olefins such as ethylene, propylene, butene, isoprene-pentene, and methylpentene, and MFR (JIS K) at 230 ° C. Measured at a test temperature of 230 ° C. and a test load of 2.16 kg according to −7210) of 3.0 g / 10 minutes or less, more preferably 0.3 to 1.5 g / 10 minutes, or acrylonitrile-butadiene-styrene. An amorphous resin such as a copolymer, polystyrene, high impact polystyrene (HIPS resin), acrylonitrile / styrene copolymer (AS resin), and a test temperature of 200 ° C. according to MFR (JIS K-7210) at 200 ° C. , Measured at a test load of 2.16 kg) at 3.0 to 60 g / 10 minutes, more preferably 30 to 50 g / 10 minutes, and melt tension at 230 ° C. (using a melt tension tester manufactured by Toyo Seiki Seisakusho Co., Ltd.). The tension when a strand is extruded from an orifice having a diameter of 2.095 mm and a length of 8 mm at a residual heat temperature of 230 ° C. and an extrusion speed of 5.7 mm / min and the strand is wound on a roller having a diameter of 50 mm at a winding speed of 100 rpm is shown. ) Is 50 mN or more, preferably 120 mN or more.

Further, in order to prevent the sheet resin from being cracked by impact, it is preferable that the hydrogenated styrene-based thermoplastic elastomer is added in the range of less than 30 wt%, preferably less than 15 wt%. Specifically, as hydrogenated styrene-based thermoplastic elastomer, styrene-ethylene / butylene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, hydrogenated styrene-butadiene rubber and a mixture thereof are preferable. The styrene content is less than 30 wt%, preferably less than 20 wt%, and the MFR at 230 ° C. (measured at a test temperature of 230 ° C. and a test load of 2.16 kg according to JIS K-7210) is 1.0 to 10 g / 10. Minutes, preferably 5.0 g / 10 minutes or less, and 1.0 g / 10 minutes or more.

Further, the sheet-like resin may contain an additive, and the additive includes an inorganic filler such as silica, mica, talc, calcium carbonate, glass fiber, and carbon fiber, a plasticizer, a stabilizer, and a colorant. , Antistatic agent, flame retardant, foaming agent and the like.
Specifically, silica, mica, glass fiber and the like are added in an amount of 50 wt% or less, preferably 30 to 40 wt%, based on the molding resin.

The operation of the molding apparatus 10 for a resin molded product having the above configuration will be described below with reference to the drawings.
First, a predetermined amount of the melt-kneaded thermoplastic resin is stored in the accumulator 24, and the stored thermoplastic resin is intermittently stored in a predetermined amount per unit time from extrusion slits 34 provided at the T-die 28 at predetermined intervals. By extruding, the thermoplastic resin swells and is extruded at a predetermined extrusion rate with a predetermined thickness so as to hang downward in the form of a molten sheet.

Next, by driving the piston-cylinder mechanism 96, as shown in FIG. 3A, the pair of rollers 30 are moved to the open position, and the distance between the pair of rollers 30 arranged below the extrusion slit 34 is large. Is expanded from the thickness of the sheet-shaped resin so that the lowermost portion of the molten sheet-shaped resin extruded downward is smoothly supplied between the pair of rollers 30. The timing of widening the distance between the rollers 30 from the thickness of the sheet-shaped resin may be performed not after the start of extrusion but at the end of secondary molding for each shot.
Next, by driving the piston-cylinder mechanism 96, as shown in FIG. 3B, the pair of rollers 30 are brought close to each other and moved to a closed position, and the distance between the pair of rollers 30 is narrowed to narrow the seat. The shape resin is sandwiched and the sheet shape resin is sent downward by the rotation of the roller, and as shown in FIG. 5, the arm part 302 is moved upward from the clamp release level (PL) to the clamp start level (PH) by the arm drive part 301. It is extended and the clamp parts 304A and B are kept open at the clamp start level (PH), and the sheet-like resin sent downward by the pair of rollers 30 is awaited, and the clamp parts 304A and B are closed to close the sheet. Clamp the lower end of the resin and pull it downward to the clamp release level (PL).
At that time, while the pair of rollers 30 are rotationally driven, the peripheral surface of the pair of rollers 30 and the sheet surface of the sheet-like resin in the molten state are in line or surface contact, and excessive slippage occurs at this contact position. To prevent this, the distance between the pair of rollers 30 is adjusted so that a constant pressing force is applied to the molten sheet-like resin.

More specifically, as shown in FIG. 26, the downward feeding speed of the sheet-shaped resin by the pair of rollers 30 while the sheet-shaped resin in the swelled state due to the rotation of the rollers 30 is fed to the pair of rollers 30. The rotation speed of the roller is adjusted so that V2 becomes the extrusion speed V1 or more of the thermoplastic sheet-like resin, and the arm so that the downward towing speed V3 of the sheet-like resin by the clamping device becomes the delivery speed V2 or more. The drive speed of the arm 302 by the drive unit 301 is adjusted.

More specifically, the step of feeding the molten sheet-like resin downward so that it can be first stretched by the rotational drive of the pair of rollers 30, and the step of second-stretching the melted sheet-like resin sent downward. In the molten state, which is composed of the difference between the thickness of the sheet-like resin in the molten state in the extrusion stage and the thickness of the sheet-like resin in the molten state in the lateral placement step of the mold in the step of pulling downward as described above. In terms of the amount of thinning of the sheet-like resin, the towing speed V3 and the feeding rate are set so that the amount of thinning of the sheet-like resin in the molten state by the first stretching is larger than the amount of thinning of the sheet-like resin in the molten state by the second stretching. It is preferable to set the relationship between the speed difference from the speed V2 and the speed difference between the feed speed V2 and the predetermined extrusion speed V1, and the speed difference between the towing speed V3 and the feed speed V2 is the speed difference between the feed speed V2 and the extrusion speed V1. Set below the speed difference.

As the swelled sheet-like resin is fed downward to the pair of rollers 30, the length of the sheet-like resin that hangs down in the vertical direction becomes longer, and as a result, the upper part of the sheet-like resin that hangs down becomes the sheet-like resin. Where the wall is thinned by its own weight (drawdown or neck-in), the rotation speed of the rollers is adjusted so that the delivery speed V2 by the pair of rollers 30 becomes the extrusion speed V1 or more, and the towing speed V3 becomes the delivery speed V2 or more. By adjusting the driving speed of the arm 302 so as to be such, the sheet-shaped resin is pulled downward between the extrusion slit and the first pair of rollers 30 and first stretched, and the pair of rollers 30 and the arm It is pulled downward with the drive unit 301 and second-stretched, whereby the sheet-like resin is stretched and thinned.
At this time, with the passage of time, the rotation speed of the roller is reduced to bring the delivery speed V2 closer to the extrusion speed V1 of the thermoplastic sheet-like resin, and the drive speed of the arm 302 is reduced to lower the traction speed V3 to the delivery speed V2. Adjust to get closer to.
In this case, it is preferable to adjust the towing speed and / or the towing time according to the desired thickness of the sheet-like resin in the molten state in the lateral arrangement step of the mold, and the clamping start is started in the towing time adjusting step. It is preferable to adjust the level (PH) and / or the clamp release level (PL).

The initial delivery speed of the pair of rollers 30 and the initial towing speed of the clamping device 30 are melted according to the difference between the thickness immediately after the extruded sheet-like resin in the molten state and the target thickness immediately before being molded by the split mold 32. In relation to the melt index of the sheet-like resin in the state, it is preferable to set the initial delivery speed and / or the initial towing speed of the pair of rollers 30 by the clamping device 30, in which case one or two types of thermoplastic resins are used. It is preferable that the above-mentioned polyolefin resin contains 5 to 40 parts by weight of an inorganic filler, and the melt index of the thermoplastic resin at 230 ° C. is 1.0 to 3.0 g / 10 min.
In particular, the towing speed of the clamp device 30 is adjusted based on the initial towing speed so that the sheet-like resin in the molten state does not draw down after being fed by the pair of rollers 30 and before being molded by the split die 32. May be.

For example, as shown in FIG. 8 (A), while keeping the extrusion speed of the thermoplastic sheet-like resin constant, the rotation speed (feeding speed) of the roller and the driving speed (towing speed) of the clamp portion by the arm driving portion are set. It may be gradually decreased with the passage of time, or as shown in FIG. 8 (B), the rotation speed of the rollers is kept constant, while the extrusion speed of the thermoplastic sheet-like resin and the drive of the clamp portion by the arm drive portion are performed. Each speed may be gradually decreased with the passage of time, or as shown in FIG. 8C, the driving speed of the clamp portion and the driving speed of the roller are within a range in which the driving speed of the clamp portion is larger than the rotation speed of the roller. Both the rotation speed and the extrusion speed of the thermoplastic sheet-like resin may be changed stepwise over time.
In any case, with the passage of time, the relative speed difference between the downward delivery speed of the sheet-shaped resin due to the rotation of the pair of rollers 30 and the extrusion speed of the sheet-shaped resin is reduced, and the pair of rollers 30 Since the relative speed difference between the downward feeding speed of the sheet-shaped resin due to rotation and the downward towing speed of the sheet-shaped resin by the arm drive unit is reduced, the upper part of the sheet-shaped resin is moved downward by the pair of rollers 30. The tensile force is reduced, the stretch thinning due to such tensile force is relatively reduced, the thinning due to drawdown or neck-in is offset, the drawdown or neck-in is effectively prevented, and the extrusion is performed. It is possible to form a uniform thickness in the direction.

In this case, as a modification, the adjustment of the spacing between the extrusion slits 34 and the adjustment of the rotation speed of the rollers and the driving speed of the clamp portion may be linked. More specifically, with the passage of time, the rotation speed of the rollers is reduced to reduce the downward feeding speed of the sheet-shaped resin by the pair of rollers 30, and the driving speed of the clamp portion is reduced to reduce the clamping. The speed of pulling the sheet-like resin downward by the portion may be reduced, and the distance between the extrusion slits 34 may be widened by using the slit gap adjusting device 42 and / or 44. As a result, at the stage of primary molding, the thickness of the sheet-like resin extruded downward from the extrusion slit 34 increases with the passage of time, and at the same time, the effect of stretching and thinning the sheet-like resin by the pair of rollers 30 and the clamp portion is reduced. Therefore, it is possible to more effectively prevent drawdown or neck-in due to the synergistic effect of thickening the sheet-like resin and reducing the stretched thin-walled effect of the sheet-like resin toward the upper part of the sheet-like resin.

In particular, as shown in FIGS. 8 (B) and 8 (C), when the extrusion speed of the sheet-shaped resin is changed during the molding of the sheet-shaped resin, the molten resin per unit time is usually generated by the plunger 26. It is necessary to change the extrusion amount of the molten resin, and if the extrusion amount of the molten resin is changed, the swell of the molten resin immediately after being extruded from the extrusion slit 34 is affected. Therefore, the sheet-like resin accompanying such a swell In order to prevent the influence of the thickening, it is preferable to adjust the rotation speed of the roller and the driving speed of the clamp portion and also adjust the spacing of the extrusion slits 34.
More specifically, as the extrusion amount per unit time is increased, the molding time from the start of the primary molding to the end of the secondary molding is shortened, thereby improving the molding efficiency and the sheet-like resin before the secondary molding. It is possible to reduce the possibility of drawdown or neck-in by shortening the time that the resin hangs down, but on the other hand, the sheet extruded from the extrusion slit 34 as the extrusion amount per unit time increases. The swell of the resin is promoted, and it may be necessary to adjust the distance between the pair of rollers 30 and / or the driving speed of the clamp portion according to the thickening accompanying the swell. In this respect, it is technically advantageous to adjust the thickening of the sheet-like resin by the swell by adjusting the spacing between the extrusion slits 34.

In this case, it is possible to adjust the thickness of the extruded sheet-like resin by adjusting the spacing between the extrusion slits 34 alone, but the rotation speed of the pair of rollers 30 and / or the driving speed of the clamp portion. It is technically advantageous to adjust the thickness of the sheet-shaped resin by adjusting the following points.

First, adjusting the rotation speed of the pair of rollers 30 and / or the driving speed of the clamp portion makes it easier to adjust the thickness of the sheet-like resin than adjusting the spacing between the extrusion slits 34. More specifically, when the extrusion amount of the molten resin per unit time is constant, the narrower the spacing between the extrusion slits 34, the smaller the swell of the sheet-like resin, but on the other hand, the extrusion pressure increases, so that the sheet-like resin Since the swell is promoted, it is difficult to preferably adjust the thickness of the sheet-like resin immediately after being extruded from the extrusion slit 34, and it is necessary to determine the spacing between the extrusion slits 34 by trial and error in the field. Furthermore, it is difficult to adjust the thickness after swelling by varying the spacing between the extrusion slits 34 during molding.

Secondly, the adjustment of the rotation speed of the pair of rollers 30 and / or the drive speed of the clamp portion is more responsive to the thickness of the sheet-like resin than the adjustment of the spacing between the extrusion slits 34. More specifically, when the interval between the extrusion slits 34 is changed, it takes time for the thickness of the sheet-like resin immediately after being extruded from the extrusion slit 34 to reach a steady state, and therefore, the sheet-like resin immediately after being extruded The portion cannot be used for secondary molding, causing a decrease in yield. On the other hand, in the case of adjusting the rotation speed of the pair of rollers 30, the downward delivery speed of the sheet-shaped resin sandwiched between the pair of rollers fluctuates as the rotation speed fluctuates, thereby causing the pair of rollers to adjust the rotation speed. Since the tensile force of the sheet-shaped resin fluctuates and the sheet-shaped resin is stretched and thinned, the responsiveness to the thickness of the sheet-shaped resin is excellent, and it is possible to suppress a decrease in yield.

Thirdly, adjusting the rotation speed of the pair of rollers 30 and / or the driving speed of the clamp portion can adjust the thickness of the sheet-shaped resin immediately before mold clamping by secondary molding rather than adjusting the distance between the extrusion slits 34. is there. More specifically, if the thickness of the sheet-like resin before mold clamping is non-uniform in the extrusion direction due to drawdown or neck-in, the shaping action of blow molding or vacuum forming is adversely affected. It is more preferable to ensure the uniformity of the thickness of the sheet-like resin immediately before, and in this respect, it is advantageous to adjust the thickness between the primary molding by extrusion and the secondary molding by blow molding or vacuum forming. ..

8 (D) to 8 (F) differ in the time from the start of clamping to the release of the clamp, that is, the time for towing the molten sheet resin by the clamping device 300, and the method of changing the towing speed. ..
More specifically, in FIGS. 8 (D) and 8 (E), the clamping device 300 keeps the extrusion speed of the molten sheet resin and the delivery speed of the molten sheet resin by the pair of rollers constant. In contrast to this, in FIG. 8 (F), while keeping the extrusion speed of the molten sheet-like resin constant, the pair of rollers feeds out the molten sheet-like resin. The speed and the towing speed of the clamping device 300 are reduced over time.

As can be seen by comparing FIGS. 8 (D) and 8 (E), in FIG. 8 (D), the towing time is shortened, the initial towing speed is increased, and the towing speed until the clamp is released is reduced. On the other hand, in FIG. 8 (E), the towing time is lengthened, the initial towing speed is slowed down, and the towing speed reduction rate until the clamp is released is slowed down.
On the other hand, in FIG. 8 (F), the clamp start and clamp release timings are slower than those in FIG. 8 (D), but the towing time is the same, and the towing speed by the clamping device 300 and the pair of rollers are used. The speed difference from the delivery speed is increased with the passage of time, unlike FIGS. 8 (D) and 8 (E).
Which of FIGS. 8 (D) to 8 (F) is selected is a viewpoint that determines the stretching mode for the sheet-shaped resin according to the physical properties of the sheet-shaped resin to be molded, particularly the melt index, MFR, and melt tension. You can decide from.
As a modification, the initial delivery speed by the pair of rollers 30 is set to the maximum in the range where the molten sheet resin cannot be torn by the first stretching, and the molten sheet resin cannot be torn by the second stretching. The initial towing speed of the clamping device 300 is set to the maximum, and the clamping device 300 is used so that the sheet-like resin in the molten state does not draw down after being fed by the pair of rollers 30 and before being molded by the split die 32. The towing speed may be adjusted based on the initial towing speed.

Next, as shown in FIG. 6, while the clamp portion 304 is at the clamp release level (PL), the clamp portion 304 releases the clamp of the sheet-like resin, resulting in a uniform thickness in the extrusion direction. The sheet-shaped resin forming the above is arranged between the split molds 32 arranged below the pair of rollers 30.
Next, as shown in FIG. 7, when the extrusion of a predetermined amount of the sheet-shaped resin is completed, the split mold 32 is molded and sucked from the vacuum suction chamber 120 through the suction hole 122 to obtain the sheet-shaped resin. By forming the shape along the mold shape by pressurizing and / or depressurizing the air between the mold and the split mold 32, the extrusion direction is not adversely affected in the shaping during the secondary molding. It is possible to mold a resin molded product having a desired thickness.
Next, as shown in FIG. 9, the split mold 32 is opened, the molded resin molded product is taken out, and the burrs formed around the parting line are removed. This completes the secondary molding.
By repeating the above steps each time the molten resin is intermittently extruded in the primary molding, it is possible to mold the sheet-shaped resin molded products one after another.
As described above, the thermoplastic resin is intermittently extruded as a sheet-like resin in a molten state by primary molding (extrusion molding), and the sheet-like resin extruded by secondary molding (blow molding or vacuum forming) is used in a mold. Can be molded.

In the present invention, after the molten resin sheet is fed by the pair of rollers, the molten resin sheet is towed by the clamp, so that the technical drawback of feeding the molten resin sheet by the pair of rollers is melted by the clamp. The resin in the molten state by the pair of rollers is compensated by towing the resin sheet in the state, and the technical defect of towing the resin sheet in the molten state by the clamp is compensated by sending out the resin sheet in the molten state by the pair of rollers. A technical synergistic effect is achieved by combining the feeding of the sheet and the towing of the molten resin sheet by the clamp.
More specifically, if an attempt is made to thin the molten resin sheet only by feeding the molten resin sheet by a pair of rollers, the feeding progresses depending on the rotation speed of the pair of rollers, that is, the adjustment of the feeding speed. At the same time, there is a limit to the suppression of drawdown caused by the own weight of the resin sheet, and the resin sheet sent out from the pair of rollers can be thinned only within the range considering that it is stretched by its own weight without being adjusted thereafter. .. That is, the melted resin sheet may be torn off depending on the length (weight) of the molten resin sheet hanging from the pair of rollers, so it is necessary to determine the thickness of the resin sheet within a range in consideration of drawdown. was there. On the other hand, after the molten resin sheet is fed out by the pair of rollers, the lower end of the molten resin sheet is towed by the clamp to uniformly cover the entire molten resin sheet portion hanging from the pair of rollers. It is possible to apply tension, thereby exerting a uniform stretching effect over the entire molten resin sheet portion hanging from the pair of rollers, suppressing drawdown and clamping. By aggressively towing the resin sheet, the thickness of the resin sheet can be adjusted so that sufficient thinning can be achieved at the timing immediately before molding the resin sheet.

On the other hand, if an attempt is made to thin the molten resin sheet only by towing the molten resin sheet with a clamp, the molten resin sheet may be torn off by increasing the towing speed. Even if the feeding speed of the molten resin sheet by the rollers is increased, the distance between the extrusion slit and the pair of rollers is short, so that the molten resin sheet is unlikely to be torn between them.
Therefore, by coordinating the stretching of the sheet-shaped resin by a pair of rollers and the stretching of the sheet-shaped resin by towing, it is possible to achieve the desired thickness of the sheet-shaped resin in the molten state when molding by the mold. Therefore, it is possible to suppress the occurrence of the neck-in phenomenon due to the increase in the feeding speed. Therefore, the thinning of the molten sheet-like resin is improved by increasing the feeding speed of the rollers, and the molten sheet-like resin is towed. Due to the synergistic effect with the thinning, it is possible to further thin the molten sheet resin, and by improving the rotation speed of the rollers, it is possible to reduce the cooling effect of the molten sheet resin by the rollers. Combined with the prevention of the neck-in phenomenon, it is also possible to maintain good moldability.
From the above, with respect to the target thickness of the molten resin sheet, the molten resin sheet is mainly thinned by stretching by feeding out the molten resin sheet by a pair of rollers, and the molten resin sheet by the pair of rollers is thinned. After feeding, the molten resin sheet is stretched by towing with a clamp to thin the molten resin sheet (auxiliarily), which makes it difficult to adjust the wall thickness of the resin sheet by drawdown and thins the thickness. The limit of conversion has been improved so that the resin sheet in the molten state immediately before molding surely reaches the target thickness.

The second embodiment of the present invention will be described below with reference to FIGS. 10 to 15. In the following description, the same components as those in the first embodiment will be omitted by assigning similar reference numbers, and the feature portions of the present embodiment will be described in detail below.
Regarding the resin molded product, in the first embodiment, it is a solid single sheet-shaped molded product, whereas in this embodiment, it is a molded product having a hollow portion using two sheets of sheet-shaped resin. Is.

Regarding the present embodiment, in the primary molding, the molten thermoplastic resin is extruded into a sheet in a form of hanging downward from the extrusion slit 34 of the T die 28, and in the secondary molding, the sheet-like resin extruded downward is used. It is common with the first embodiment in that the resin molded product is molded by vacuum molding through the mold clamping of the split mold 32, but in the present embodiment, two sheet-shaped resins are molded at the same time, and at that time, each Regarding the sheet-like resin, the molten thermoplastic resin is extruded into a sheet shape so as to hang down from the extrusion slit 34 of the T-die 28, and in the secondary molding, it is divided using the two-row sheet-like resin extruded downward. The difference from the first embodiment is that the resin molded product is molded by vacuum molding through the mold clamping of the mold 32.
As shown in FIGS. 10 and 11, with respect to the primary molding of each of the two sheet-shaped resins, the extrusion speed and the sheet-shaped resin are determined according to the extrusion speed of each sheet-shaped resin, as in the first embodiment. The relative speed difference from the delivery speed sent downward by the pair of rollers 30 is adjusted by adjusting the rotation speed of the pair of rollers 30, and the delivery speed by the pair of rollers 30 and the downward towing by the clamp portion 304. The relative speed difference from the speed is adjusted by adjusting the driving speed of the arm driving unit 301, so that when the sheet-like resin passes between the pair of rollers 30, it is pulled downward by the pair of rollers 30 (the first). Along with (1 stretching), it is pulled downward by the clamp portion (2nd stretching), whereby the sheet-like resin is stretched and thinned, and as a result, the occurrence of drawdown or neck-in is effectively prevented. The rotation speed of the pair of rollers 30 and the driving speed of the arm driving unit 301 may be adjusted, and the spacing between the extrusion slits 34 may be adjusted in conjunction with each other.
In this case, the first predetermined traction speed is adjusted according to the change in the first predetermined delivery speed between the extrusion stage of the first thermoplastic resin and / or the second thermoplastic tree and the molding stage of the resin molded product. It is preferable to have a step or a step of adjusting the second predetermined traction speed according to a change in the second predetermined delivery speed.

Regarding the secondary molding, first, as shown in FIG. 11, each of the two sheet-shaped resins is arranged between the split dies 32A and B.
Next, as shown in FIG. 12, the molds 33A and B of the split dies 32A and B are moved toward the corresponding side of the two sheet-shaped resins with respect to the corresponding split dies. It is brought into contact with the side surface of the sheet-shaped resin. As a result, a closed space is formed by each sheet-like resin, the corresponding mold 33, and the cavity 116.

Then, as shown in FIG. 13, by sucking the air in the closed space from the vacuum suction chamber 120 through the suction hole 122, the two sheet-shaped resins are each adsorbed to the corresponding cavities 116, and the two sheets of resin are adsorbed to the corresponding cavities 116. Each of the two sheet-like resins is shaped along the surface of the corresponding cavity 116. In this case, since the thickness of the two sheets of resin before suction is uniform in the vertical direction, the shaping process may not be performed satisfactorily due to the thickness distribution caused by the blow ratio. It is possible to prevent it.
Next, as shown in FIG. 14, the molds 33A and B and the split dies 32A and B are integrally moved so as to be close to each other, thereby clamping the split dies 32A and B and the split dies. The peripheral portions of the two sheet-shaped resins are welded to each other by the pinch-off portions of the molds 32A and B respectively. As a result, the closed hollow portion 151 is formed inside the two-row sheet-shaped resin.

Next, as shown in FIG. 15, the molds 33A and B and the split dies 32A and B were integrally moved so as to be away from each other, so that the split dies 32A and B were opened and molded. The resin molded product is taken out, burrs on the outer periphery are removed, and the secondary molding is completed.

When a resin molded product having a hollow portion is molded using a tubular parison as in the conventional case, it is technically difficult to mold a molded product having a uniform thickness due to the blow ratio. According to the embodiment, a hollow having a uniform thickness is obtained by welding the peripheral portions of the two-row sheet-shaped resin to each other by secondary molding using the two-row sheet-shaped resin having a uniform thickness. It is possible to mold a molded product having a portion.
As described above, according to the present embodiment, when a resin molded product having a hollow portion inside is molded using the two-row sheet-shaped resin, each sheet-shaped resin is formed by adjusting the number of rotations of the pair of rollers 30. By making the thickness uniform in the extrusion direction before the secondary molding, the resin is molded into a sheet having a desired thickness by the secondary molding without adversely affecting the shaping of the secondary molding. Therefore, using such two-row sheet-shaped resin, the peripheral edges of the sheet-shaped resin are welded to each other by mold clamping to form a resin molded product having a hollow portion inside. , The peripheral edges of the sheet-shaped resin are surely welded to each other, whereby it is possible to obtain a resin molded product having sufficient strength in spite of having a hollow portion inside.

The third embodiment of the present invention will be described below with reference to FIGS. 16 to 25. In the following description, the same components as those in the second embodiment will be omitted by assigning similar reference numbers, and the feature portions of the present embodiment will be described in detail below.
Regarding the resin molded product, in the second embodiment, it is a molded product having a hollow portion using two sheets of resin, whereas in the present embodiment, a sandwich in which a reinforcing core material is arranged in the hollow portion. It is a panel molded product.
Regarding the present embodiment, in the primary molding, two sheet-shaped resins are molded, and at that time, for each sheet-shaped resin, a molten thermoplastic resin is hung down from the extrusion slit 34 of the T-die 28 in a sheet shape. In the secondary molding, the resin molded product is molded by blow molding or vacuum molding through the mold clamping of the split mold 32 using the two-row sheet-shaped resin extruded downward, which is common to the second embodiment. However, in the second embodiment, regarding the secondary molding, a closed hollow portion is formed inside the two-row sheet-shaped resin, whereas in the present embodiment, a closed hollow portion is separately molded in such a closed hollow portion. The difference is that the reinforcing core material is arranged to form a sandwich panel in which the reinforcing core material is sandwiched between two sheets of resin.

Regarding the sandwich panel molding apparatus, a pair of frame members 128A and B are arranged between the split dies 32A and B in a nested manner with the pair of dies 32A and B, substantially parallel to the cavity 116, and a pair of frames. The members 128A and B have openings 130A and B, respectively, and the pair of frame members 128A and B are moved in the horizontal direction by a frame member driving device (not shown). As a result, each of the pair of frame members 128A and B is moved toward the corresponding molten sheet-shaped resin to hold the sheet-shaped resin, and in that state, the corresponding molds 32A and B are pinched off in the opposite direction. The tip of the portion 118 can be moved to abut with the surface of the sheet-shaped resin through the opening 130.

In the present embodiment, the material of the reinforcing core material 150 is a polyolefin (for example, polypropylene, high-density polyethylene) which is a homopolymer or copolymer of olefins such as ethylene, propylene, butene, isoprenepentene, and methylpentene. Acrylic derivatives such as polyamide, polystyrene, polyvinyl chloride, polyacrylonitrile, ethylene-ethyl acrylate copolymers, vinyl acetate copolymers such as polycarbonate and ethylene-vinyl acetate copolymers, ionomers, ethylene-propylene-dienes and the like. Examples thereof include thermoplastic resins such as tarpolymers, ABS resins, polyolefin oxides, and polypropylenes.

It should be noted that these may be used alone or in combination of two or more. In particular, among the thermoplastic resins, the olefin resin or the resin mainly composed of the olefin resin, the polypropylene resin or the resin mainly composed of the polypropylene resin has a balance of weldability, mechanical strength and moldability with the fiber layer. It is preferable in that it is excellent in. The reinforcing core material 150 may contain an additive, and the additive includes an inorganic filler such as silica, mica, talc, calcium carbonate, glass fiber, and carbon fiber, a plastic agent, a stabilizer, and a colorant. Examples thereof include antistatic agents, flame retardants, and foaming agents.

The sheet-shaped resin constituting the skin material 160 may be the same as that of the first embodiment, but in the case of a sandwich panel as a strength material in particular, the distance between the pair of skin materials 160 provided on both sides of the reinforcing core material 150. That is, from the viewpoint of ensuring the rigidity of the sandwich panel as a whole, particularly the flexural rigidity, by ensuring the bulk (thickness) of the reinforcing core material 150, the rigidity of the skin material 160 is at least higher than the rigidity of the reinforcing core material 150. Material is required.

When the decorative material sheet 170 is provided on the surface of the skin material 160, the decorative material sheet 170 is placed on the upper surface of the board in terms of appearance improvement, decorativeness, and contact with a molded product (for example, in the case of a cargo floor board). It is configured for the purpose of protecting luggage, etc. As the material of the decorative material sheet 170, a fiber skin material, a sheet-like skin material, a film-like skin material, or the like is applied. Materials of such fiber skin materials include synthetic fibers such as polyester, polypropylene, polyamide, polyurethane, acrylic and vinylon, semi-synthetic fibers such as acetate and rayon, recycled fibers such as biscous rayon and copper ammonia rayon, cotton and hemp. Natural fibers such as wool and silk, or blended fibers thereof can be mentioned.

Among these, polypropylene or polyester is preferable, and polyester is more preferable, from the viewpoint of tactile sensation, durability and moldability. The yarn used for the fiber skin material is, for example, polyester: (3 to 5) denier x (50 to 100) mm, etc., with a fineness of 3 to 15 denier and a fiber length of about 2 to 5 inches. , Polyester with bundles of thin flexible filaments: Approximately 150 to 1000 denier / 30 to 200 filaments = Approximately 5 denier x 30 to 200 multifilaments, or polyester: 400 to 800 denier / 1 filament or other thick material -It is preferable to use a filament in combination.

Examples of the structure of the decorative material sheet 170 include non-woven fabrics, woven fabrics, knitted fabrics, and brushed fabrics. The woven fabric includes a plain weave in which the warp and weft threads are sequentially entwined in the vertical direction, and various variable weaves in which several threads are jumped over and entangled. Among these, a non-woven fabric is preferable because it has no directionality with respect to elongation, is easy to form into a three-dimensional shape, and has excellent surface texture and texture. Here, the non-woven fabric means a cloth-like product formed by stacking fibers in parallel or alternately or by randomly spraying them to form a web, and then joining the fibers that have become the web. Among these, a non-woven fabric produced by the needle punch method is preferable from the viewpoint of three-dimensional shape reproducibility and appearance characteristics of the molded product. In addition, the non-woven fabric obtained by the needle punch method has lower strength and higher elongation than the woven fabric and has a large degree of deformation in any direction. Therefore, the strength of the non-woven fabric is improved and the dimensions are stabilized. Therefore, it is more preferable to attach a binder to the non-woven fabric or to punch the web and the non-woven fabric with a stacking needle. From these facts, it is more preferable that the decorative material sheet 170 is a polypropylene non-woven fabric or a polyester non-woven fabric. In this case, since the decorative material sheet 170 itself is thermoplastic, it can be used for another purpose by heating and deforming after peeling and collecting. For example, if the main resin layer is made of polypropylene and the decorative material sheet 170 is made of polypropylene non-woven fabric, the main resin layer of the molded product and the decorative material sheet 170 are made of the same material, which facilitates recycling.

On the other hand, when the decorative material sheet 170 is a polyester non-woven fabric, the melting point of the main resin layer composed of polypropylene and the fiber skin material are different, so that when the decorative material sheet 170 is adhered to the molded product, it is deteriorated and deformed by heat. It is possible to prevent problems such as being unable to adhere to the correct position. Further, in this case, the moldability, rigidity, appearance and durability are also excellent. Further, the tensile strength of the decorative material sheet 170 is preferably 15 kg / cm ² or more, and the elongation is preferably 30% or more, from the viewpoint of three-dimensional shape reproducibility and moldability. The values of tensile strength and elongation are measured at a temperature of 20 ° C. in accordance with JIS-K-7113. As the sheet-shaped skin material and the film-shaped skin material, a thermoplastic elastomer, an embossed resin layer, a resin layer having a printed layer on the outer surface, synthetic leather, a non-slip mesh-shaped skin layer, and the like can be used. ..

Next, a method for forming such a sandwich panel 10 will be described.
First, as shown in FIG. 18, a sheet-shaped decorative material sheet 170 is inserted from the side of the two split dies 32 between one of the split dies 32 and one of the frame members 128, and one of the split dies 32 is inserted. A sheet-shaped decorative material sheet 170 is temporarily fixed so as to cover the cavity 116 of one of the split molds 32 by a temporary fixing pin 303 (not shown) provided on the mold 32.

Next, as shown in FIG. 19, each of the two molten sheet-like resins is extruded vertically downward from each extrusion slit 34.
At that time, as shown in FIGS. 16 and 17, similarly to the first embodiment and the second embodiment, the extrusion speed of the sheet-shaped resin from the extrusion slit 34 and the sheet-shaped resin are lowered by the pair of rollers 30. The relative speed difference from the feed-out speed is adjusted by adjusting the rotation speed of the pair of rollers 30, and the relative speed difference between the feed-out speed by the pair of rollers 30 and the downward towing speed by the clamp portion 304 is adjusted. It is adjusted by adjusting the drive speed of the arm drive unit 301, and when the sheet-like resin passes between the pair of rollers 30, it is pulled downward by the pair of rollers 30 (first stretching) and the clamp portion. (Second stretching), which causes the sheet-shaped resin to be stretched and thinned, thereby preventing the occurrence of drawdown or neck-in, and extruding each sheet-shaped resin before mold clamping by secondary molding. It is possible to form a uniform thickness in the direction. In this case, the rotation speed of the pair of rollers 30 and the driving speed of the arm driving unit 301 may be adjusted, and the spacing between the extrusion slits 34 may be adjusted in conjunction with each other.

Next, the two sheet-shaped resins are supplied between the two split molds 32, and the pair of frame members 128 are moved toward the corresponding sheet-shaped resins by the frame member driving device.
Next, as shown in FIG. 20, the frame member 128 holding the sheet-shaped resin is passed through the opening 130 of the frame member 128 toward the corresponding split mold 32, and the pinch-off portion 118 of the mold 32 is formed in the sheet-shaped resin cavity 116. Move until it comes into contact with the surface facing the surface. As a result, a closed space is formed by the surface of the sheet-like resin facing the cavity 116, the pinch-off portion 118, and the cavity 116.

Then, as shown in FIG. 21, the inside of the closed space is sucked through each of the divided dies 32, whereby the corresponding sheet-like resin is pressed against the cavity 116 and shaped into a shape along the cavity 116. .. The sheet-shaped resin on the left side of the drawing is shaped and welded to the decorative material sheet 170 interposed between the sheet-shaped resin and the cavity 116.

Next, as shown in FIG. 22, the reinforcing core material 150 held by the suction plate 119 of the manipulator (not shown) is inserted laterally between the two split dies 32.

Next, as shown in FIG. 23, by moving the manipulator horizontally toward the split mold 32 on the right side, a reinforcing core material is provided for the sheet-like resin adsorbed in the cavity 116 of the split mold 32 on the right side. Press 150. As a result, the reinforcing core material 150 is welded to the sheet-shaped resin. Next, the suction plate 119 is detached from the reinforcing core material 150, and the manipulator is pulled out from between the two split dies 32 to prepare for mold clamping.
Next, as shown in FIG. 24, the mold driving device moves the two split molds 32 to the closed position in a direction closer to each other than the open position, and molds the mold. As a result, the reinforcing core material 150 welded to one sheet-shaped resin (on the right side of the drawing) is welded to the other sheet-shaped resin, and the peripheral edges of the sheet-shaped resins are welded to form a parting line PL. To. At the time of mold clamping, the reinforcing core material 150 itself is different from the skin material sheet 160, and is welded to the skin material sheet 160 in a molten state in a preformed state. Therefore, the reinforcing core material 150 itself is a mold. It is pre-positioned so that it will not be deformed by tightening.

With the above, the sandwich panel 10 in which the decorative material sheet 170, the skin material sheet 160, the reinforcing core material 150, and the skin material sheet 160 are laminated is completed.
Next, as shown in FIG. 25, the two split molds 32 are opened, the cavity 116 is separated from the completed sandwich panel 10, and the burrs formed around the parting line PL are removed. This completes the molding of the sandwich panel.
According to the present embodiment, by adjusting the number of rotations of the pair of rollers 30 and the driving speed of the arm driving unit 301, the thickness of each sheet-shaped resin is made uniform in the extrusion direction before secondary molding. Since it is possible to form a sheet having a desired thickness by secondary molding without adversely affecting the shaping of secondary molding, such a double-row sheet-like resin is used as a skin material. Then, the peripheral edges of the sheet-shaped resin are welded together by molding the mold to form a panel sandwich having a reinforcing core material inside, and the peripheral edges of the sheet-shaped resin, which is the skin material, are surely welded to each other. This makes it possible to obtain a sandwich panel that requires sufficient strength, particularly bending rigidity, such as a cargo floor board for automobiles.

Although the embodiments of the present invention have been described in detail above, those skilled in the art can make various changes or modifications within the scope of the present invention. For example, in the first embodiment, the case where the occurrence of drawdown or neck-in is prevented and the thickness of the resin molded product is made uniform has been described, but the present invention is not limited to this, and the secondary molding is more positively performed. The rotation speed of the pair of rollers and the drive speed of the arm drive unit 301 may be adjusted so that the thickness of the resin molded product has a desired thickness distribution in the extrusion direction before molding.
Further, in the second embodiment, a case where the resin molded product having a hollow portion is molded by using two sheets of resin having the same resin type and color is described, but the present invention is not limited to this, for example, a game. Two sheets of resin of different types or colors may be formed as the back surface and the front surface for the casing of the machine.
Further, in the third embodiment, the case where the decorative material sheet is arranged between the split molds and welded to the skin material sheet by the mold clamping of the split molds has been described, but the case is not limited thereto. A decorative material sheet is supplied between the pair of rollers together with the sheet-shaped resin for use, and the thickness of the sheet-shaped resin is adjusted by adjusting the rotation speed of the pair of rollers and the driving speed of the arm driving unit 301, and the decorative material sheet is adjusted. May be crimped to a sheet-like resin.

The clamp start level may be set to a level between the split molds 32 that are open in order to shorten the towing time when, for example, the towing speed by the clamping device 300 is set to be large.
The timing for releasing the clamp of the sheet-like resin at the clamp release level is unstable when the sheet-like resin hangs down from the pair of rollers 30, so it is preferable after the split mold 32 is clamped. In the case of vacuum suctioning toward the cavity 116, the split mold 32 may be unclamped after vacuum suction and before mold clamping.
The towing of the sheet-shaped resin by the clamping device 300 not only prevents the draw-down of the sheet-shaped resin hanging from the pair of rollers 30 as an aid to the feeding of the sheet-shaped resin by the pair of rollers 30, but also melts the sheet-shaped resin. Adjustment of the initial towing speed of the sheet-like resin, adjustment of the clamp start level and / or clamp release level, or adjustment of the time history of the towing speed in relation to the delivery speed by the pair of rollers 30 according to the physical property values such as the index. By doing so, it may be used in cooperation with the pair of rollers 30 to achieve uniform thinning in the extrusion direction of the sheet-shaped resin.
Further, in each of the first to third embodiments, at the extrusion stage of the thermoplastic resin sheet, the molten thermoplastic resin is extruded from the extrusion head to obtain a sheet-like resin, but the present invention is limited thereto. Instead, a tubular parison made of a molten thermoplastic resin may be used to divide the resin into two sheets at the tip of the extrusion head.

It is a schematic side view of the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. It is schematic cross-sectional view which shows the detail around the extrusion slit of the T die of the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. It is a schematic side view which shows around a pair of rollers of the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. It is a schematic plan view which shows around a pair of rollers of the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. It is a schematic side view which shows the state which the sheet-like resin is clamped in the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. FIG. 5 is a schematic side view showing a state in which a sheet-shaped resin is arranged between split dies in a molding apparatus for a resin molded product according to a first embodiment of the present invention. FIG. 5 is a schematic side view showing a state in which a split mold is molded in a molding apparatus for a resin molded product according to a first embodiment of the present invention. It is a simplified graph which shows the change with time of the extrusion speed of a sheet resin, the rotation speed of a roller, and the towing speed by a clamp in the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. It is a schematic side view which shows the state which the split die is opened in the molding apparatus of the resin molded article which concerns on 1st Embodiment of this invention. It is the same figure as FIG. 5 of the molding apparatus of the resin molded article which concerns on 2nd Embodiment of this invention. It is the same figure as FIG. 6 of the molding apparatus of the resin molded article which concerns on 2nd Embodiment of this invention. FIG. 5 is a schematic side view showing a state in which two sheets of resin are sucked by a split mold in a molding apparatus for a resin molded product according to a second embodiment of the present invention. FIG. 5 is a schematic side view showing a state in which each of the two sheet-shaped resins is vacuum-formed by a split mold in the molding apparatus for a resin molded product according to the second embodiment of the present invention. FIG. 5 is a schematic side view showing a state in which a split mold is molded in a molding apparatus for a resin molded product according to a second embodiment of the present invention. It is a schematic side view which shows the state which the split die was opened in the molding apparatus of the resin molded article which concerns on 2nd Embodiment of this invention. It is the same figure as FIG. 5 of the sandwich panel molding apparatus which concerns on 3rd Embodiment of this invention. It is the same figure as FIG. 6 of the sandwich panel molding apparatus which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which arranged the decorative material sheet between the molds of the split type in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which arranged the skin material sheet between the molds of the split type in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which brought the skin material sheet into contact with the mold of the split type in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which shaped the skin material sheet in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which arranged the core material sheet between the molds of a split type in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which pressed the core material sheet against one skin material sheet in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which the mold of the split type was molded in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. It is a figure which shows the state which the mold of the split type was opened in the molding process of the sandwich panel which concerns on 3rd Embodiment of this invention. The relationship between the extrusion speed of the molten sheet-like resin, the delivery speed by the pair of rollers, and the towing speed by the clamp device 300 in the molding apparatus for the resin molded product according to each of the first to third embodiments of the present invention is shown. It is a schematic diagram.

P Parison PL Parting line PH Clamp start level PL Clamp release level V1 Pushing speed V2 Feeding speed V3 Towing speed 10 Molding device 12 Extruding device 14 Mold clamping device 16 Hopper 18 Cylinder 22 Hydraulic motor 24 Accumulator 26 Plunger 28 T-die 30 Roller 32 Divided mold 34 Extrusion slit 36 Die lip 38 Die 40 Slit gap 42 Slit spacing adjustment device 44 Slit spacing drive device 46 Die bolt 48 Pressure transmission part 50 Adjustment shaft 52 Fastening bolt 54 Engagement piece 56 Concave groove 58 Sliding bar 60 Drive piece 62 Sliding groove 94 Roller rotation driving means 96 Roller moving means 98 Rotation drive motor 100 Rotation speed adjusting device 102 End peripheral surface 104 First gear 106 End peripheral surface 108 Second gear 110 Piston-cylinder mechanism 112 Shallow groove 114 Roller surface temperature Adjusting means 116 Cavity 118 Pinch-off part 120 Vacuum suction chamber 122 Suction hole 124 Pressure fluid introduction hole 126 Form 128 Frame member 130 Opening 300 Clamping device 301 Arm drive part 302 Arm part 303 Pin 304 Clamping part

Claims (13)

The stage of extruding the thermoplastic resin at a predetermined extrusion speed so that it hangs down like a molten sheet, and
The stage of towing the molten sheet-like resin that is extruded downward at a towing speed higher than the extrusion speed, and
The stage of arranging the towed molten sheet resin on the side of the mold, and
A step of decompressing the closed space formed between the molten sheet-shaped resin and the mold and / or pressing the sheet-shaped resin toward the mold to form a shape along the mold shape. Have and
A method for molding a resin molded product, which comprises reducing the towing speed with the passage of time in the towing step . The method for molding a resin molded product according to claim 1 , wherein in the towing step, the towing speed is gradually reduced with the passage of time. The towing step includes a step of clamping the lowermost portion of the molten sheet-like resin extruded downward.
It has a step of towing the bottom of the clamped sheet resin downward,
The towing step is performed between the clamp start position at the bottom of the molten sheet resin and the clamp release position at the bottom of the melted sheet resin at a level below the clamp start position.
The clamp start position is set to a level between the extrusion start position and the mold, and the clamp release position is set to a level below the mold.
The clamp start level and clamp release level of the molten sheet resin are determined according to the length of the cavity along the extrusion direction of the cavity, which is determined according to the dimensions of the molded product. , Determine the towing speed of the clamp device,
The method for molding a resin molded product according to claim 1 or 2, wherein the resin molded product is characterized in that. The method according to any one of claims 1 to 3 , further comprising a step of adjusting the towing speed and / or the towing time according to a desired thickness of the sheet-like resin in a molten state in the step of arranging the mold laterally. The method for molding a resin molded product according to the above . The method for molding a resin molded product according to claim 4, wherein the towing time adjusting step includes a step of adjusting the level of the clamp start position and / or the clamp release position. The initial towing downward in relation to the melt index of the molten sheet resin according to the difference between the thickness immediately after the extruded sheet resin in the molten state and the target thickness immediately before being molded by the mold. The method for molding a resin molded product according to any one of claims 1 to 5 , wherein the towing speed is set. Thermoplastic resin, an inorganic filler is contained 5 to 40 parts by weight to one or more types of polyolefin resin, melt index at 230 ° C. for the thermoplastic resin is 1.0 to 3.0 g / 10min, wherein Item 6. The method for molding a resin molded product according to Item 6 . The first sheet-like resin is placed between the split dies by arranging the first and second molten sheet-like resins and depressurizing the air between one mold of the split dies and the first sheet-like resin. Is brought into close contact with one mold cavity, and the second sheet resin is brought into close contact with the other mold cavity by reducing the air pressure between the other mold of the split mold and the second sheet resin. , Has a stage to mold the split mold,
Any of claims 1 to 7 , wherein a resin molded product is molded by welding and integrating the first and second sheet-shaped resins through a pinch-off forming portion on the outer periphery of the mold by mold clamping of the split mold. A method for molding a resin molded product according to the above . The method for molding a resin molded product according to claim 8, wherein the resin molded product to be molded has a closed hollow portion. The thermoplastic according to claim 8 or 9 , further comprising a clamp portion for clamping the first sheet-shaped resin and a clamp portion for clamping the second sheet-shaped resin, and the pair of clamp portions are synchronized with each other. Resin molding method. The thermoplastic resin is shaped by extrusion molding, and the primary molding part that extrudes the primary molded thermoplastic resin in a hanging form and the thermoplastic resin extruded by the primary molding part are secondary molded by blow molding or vacuum forming. In a thermoplastic resin molding apparatus having a secondary molding portion,
The primary molding part is
Melt-kneading means for melt-kneading thermoplastic resin,
A storage means for storing a predetermined amount of melt-kneaded thermoplastic resin,
It has an extrusion slit that intermittently extrudes the stored thermoplastic resin so as to hang down in the form of a molten sheet.
The secondary molding part is
A pair of split dies that are movable in a direction substantially orthogonal to the sheet surface between the open position and the closed position with the hanging sheet-like resin sandwiched between them and have cavities formed on the surfaces facing each other.
It has a mold moving means for moving a pair of split molds in a direction substantially orthogonal to the sheet surface between the open position and the closed position.
Further, a clamp portion capable of clamping the lowermost portion of the sheet-like resin extruded downward, a clamp portion moving means for moving the clamp portion in the vertical direction, and a clamp portion moving means for moving the clamp portion in the vertical direction. It has a clamp portion moving speed adjusting means for adjusting the moving speed, and a sheet-like resin towing means provided with the clamp portion moving speed adjusting means.
The clamp portion moving speed adjusting means adjusts the moving speed of the clamp portion so as to tow the molten sheet-like resin extruded downward at a towing speed equal to or higher than the extrusion speed .
Further, the clamp portion moving speed adjusting means is a thermoplastic resin molding apparatus characterized in that the towing speed is reduced with the passage of time . The thermoplastic according to claim 11 , wherein the clamp portion extends over a predetermined length so that a molten sheet resin having a predetermined width in a direction orthogonal to the extrusion direction can be clamped. Resin molding equipment. The first sheet-like resin is placed between the split dies by arranging the first and second molten sheet-like resins and depressurizing the air between one of the split dies and the first sheet-like resin. Is brought into close contact with one mold cavity, and the second sheet resin is brought into close contact with the other mold cavity by reducing the air pressure between the other mold of the split mold and the second sheet resin. , A resin molded product that molds a resin molded product by molding the split mold and welding and integrating the first and second sheet-shaped resins through the pinch-off forming portion on the outer periphery of the mold by molding the split mold. It is a molding device of
The thermoplastic according to claim 11 or 12 , which has a clamp portion for clamping the first sheet-shaped resin and a clamp portion for clamping the second sheet-shaped resin, and the pair of clamp portions are synchronized with each other. Resin molding equipment.

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