JP2013103451A - Method of manufacturing thermoplastic resin molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a thermoplastic resin molded body capable of obtaining a thermoplastic resin molded body having high rigidity and impact strength, and favorable appearance.SOLUTION: The method of manufacturing a thermoplastic resin molded body includes a resin-supplying process of supplying a molten thermoplastic resin R between a pair of molds 7a, 7b, and a forming process of clamping a pair of the molds 7a, 7b to form the thermoplastic resin R. The temperature of at least one part of a cavity face of the molds corresponding to a design face side of the thermoplastic resin molded article when beginning to form the thermoplastic resin in the forming process is not lower than a temperature lower by 30°C than a deflection temperature under load of the thermoplastic resin. The temperature of the thermoplastic resin R when beginning to form is not lower than a temperature lower by 20°C than a melting point of the thermoplastic resin R and not higher than a temperature higher by 10°C than the melting point. The velocity V of clamping the molds in the forming process is greater than 30 mm/sec and not greater than 500 mm/sec.

Description

  The present invention relates to a method for producing a thermoplastic resin molded body.

  2. Description of the Related Art Conventionally, as a method for producing a thermoplastic resin molded body, a method is known in which a molten thermoplastic resin is supplied between a pair of male and female molds and then molded by clamping the mold. (Patent Document 1).

JP 2005-313590 A

  A thermoplastic resin molded article having higher rigidity and impact strength is desired than a conventional thermoplastic resin molded article, and a thermoplastic resin molded article having higher rigidity and impact strength can be obtained with respect to a method for producing the molded article. A method for producing a thermoplastic resin molded body has been desired.

  Then, an object of this invention is to provide the manufacturing method of the thermoplastic resin molded object which can obtain the thermoplastic resin molded object with high rigidity and impact strength and a favorable external appearance.

As a result of intensive studies to solve the above problems, the present invention has been completed.
That is, the present invention includes a resin supply step for supplying a molten thermoplastic resin between a pair of molds, and a molding step for shaping the thermoplastic resin by clamping the pair of molds. A method for producing a thermoplastic resin molded body, wherein when molding of a thermoplastic resin is started in a shaping process, the temperature of at least a part of a cavity surface of a mold corresponding to the design surface side of the thermoplastic resin molded body Is not less than 30 ° C lower than the deflection temperature under load of the thermoplastic resin, and the temperature of the thermoplastic resin when the shaping of the thermoplastic resin is started is 20 ° C lower than the melting point of the thermoplastic resin, more than the melting point. This is a method for producing a thermoplastic resin molded body having a temperature not higher than 10 ° C. and the mold clamping speed in the shaping step being higher than 30 mm / second and not higher than 500 mm / second.

  In a preferred embodiment of the method for producing a thermoplastic resin molded body described above, in the resin supplying step, a pair of molten thermoplastic resins is passed through a temperature adjusting die attached to an outlet of a melt plasticizing apparatus that melts the thermoplastic resin. Is a method for producing a thermoplastic resin molded body in which the temperature of the molten thermoplastic resin is adjusted in a temperature adjusting die.

  Another preferable aspect of the method for producing a thermoplastic resin molded body described above is a method for producing a thermoplastic resin molded body in which a cavity formed by a pair of molds has a three-dimensional shape having uneven portions.

  Another preferable aspect of the method for producing a thermoplastic resin molded body described above is a thermoplastic resin molding in which the shaping step is a step of shaping the thermoplastic resin into a shape having an average thickness of 1 mm or more and 5 mm or less. It is a manufacturing method of a body.

  According to the present invention, it is possible to obtain a thermoplastic resin molded article having high rigidity and impact strength and having a favorable appearance.

It is a figure which shows the shaping | molding apparatus used with the manufacturing method of the thermoplastic resin molding which concerns on this embodiment. It is a figure which shows the resin supply process by the shaping | molding apparatus of FIG. It is a figure which shows the shaping process by the shaping | molding apparatus of FIG. It is a perspective view which shows the die | dye for temperature control. It is a top view which shows the die for temperature control. It is sectional drawing along the VI-VI line of FIG. It is sectional drawing along the VII-VII line of FIG. It is sectional drawing along the VIII-VIII line of FIG. (A) It is a figure which shows the state of the thermoplastic resin after a resin supply process. (B) It is a figure which shows the state of the thermoplastic resin at the time of a shaping start. (C) It is a figure which shows the state of the thermoplastic resin at the time of mold clamping completion. It is a figure which shows the state of the thermoplastic resin after a mold release process. It is a figure which shows the other example of the metal mold | die which can be utilized with the manufacturing method of the thermoplastic resin molding which concerns on this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the method for manufacturing a thermoplastic resin molded body according to the present embodiment is a so-called press molding method, and a thermoplastic resin molded body is manufactured using a molding apparatus 1 for press molding. To do.

(Molding equipment)
Hereinafter, the molding apparatus 1 will be described. The molding apparatus 1 according to this embodiment includes a resin supply device 2 and a press device 3.

  The resin supply device 2 includes an extruder (melt plasticizer) 4 that melts the thermoplastic resin R, a moving mechanism 5 that moves the extruder 4, and temperature adjustment of the thermoplastic resin R that is extruded from the extruder 4. And a temperature adjusting die 6 to be used.

  The extruder 4 has a hopper 4a, a drive unit 4b, and a melt plasticizing cylinder 4c. The thermoplastic resin R is introduced into the melt plasticizing cylinder 4c from a hopper 4a provided upstream of the melt plasticizing cylinder 4c. The thermoplastic resin R is melted by the rotation of the screw inside the heated melt plasticizing cylinder 4c and is extruded in the downstream direction of the cylinder. The screw used here may be uniaxial or biaxial.

  The moving mechanism 5 is a mechanism for moving the extruder 4 with respect to the press device 3. As such a moving mechanism 5, for example, an XY stage mechanism can be adopted.

  The temperature adjusting die 6 is attached to the outlet of the melt plasticizing cylinder 4 c of the extruder 4. The molten thermoplastic resin R extruded from the melt plasticizing cylinder 4 c of the extruder 4 is supplied to the press device 3 through the temperature adjusting die 6. The temperature adjusting die 6 adjusts the temperature of the resin supplied to the press device 3.

  Hereinafter, the configuration of the temperature adjusting die 6 will be described in detail with reference to FIGS.

  As shown in FIGS. 4 and 5, the temperature adjusting die 6 includes an inlet portion 10 into which the molten thermoplastic resin R is introduced from the extruder 4, and a land portion where the temperature of the thermoplastic resin R is adjusted. 11 and a joining outlet portion 12 through which the thermoplastic resin R is pushed out.

  As shown in FIGS. 4, 6, and 7, the inlet portion 10 has an inlet flow path A into which the molten thermoplastic resin R is introduced from the melt plasticizing cylinder 4 c of the extruder 4. . The molten thermoplastic resin R introduced into the inlet channel A flows in the flow direction T1 indicated by the arrow and flows into the land portion 11.

  6-8, the land part 11 has the main-body part 11a which forms the several flow path B through which the molten thermoplastic resin R flows. Thick plate-like side guides 11b and 11c are arranged on the left and right sides of the main body 11a. The thick plate-like side guides 11 b and 11 c are fixed to the main body 11 a by bolts 13. The land portion 11 is mostly composed of a general structural material such as iron or carbon steel.

  The plurality of flow paths B are linear flow paths extending in the flow direction T1. The plurality of flow paths B are formed in a line from one end of the main body 11a to the other end of the main body 11a in a direction orthogonal to the flow direction T1 (the lateral width direction of the main body 11a). The flow path B does not necessarily have to be formed from one end of the main body 11a to the other end of the main body 11a, but only near the center of the main body 11a in the direction perpendicular to the flow direction T1. It may be formed, or may be formed at one of the left and right ends.

  As shown in FIGS. 4, 6, and 8, the main body 11 a is provided with a plurality of cooling water pipes 14 and cartridge heaters 15. The cooling water pipe 14 is a cooler that cools the thermoplastic resin R flowing through the flow path B by circulating the cooling water. The cartridge heater 15 is a heater that heats the thermoplastic resin R flowing through the flow path B by electric heat.

  The cooling water pipe 14 and the cartridge heater 15 are respectively arranged on the upper side and the lower side of the flow path B, and a plurality of the cooling water pipes 14 and the cartridge heaters 15 are arranged along the flow direction T1 in the main body 11a. 5 and 7, the illustration of the cooling water pipe 14 and the cartridge heater 15 is omitted.

  As shown in FIGS. 4 to 6, a temperature sensor 16 for detecting the temperature of the thermoplastic resin R flowing through the flow path B is attached to the upper side of the land portion 11. The temperature sensor 16 has a rod-shaped detection unit 16a inserted into the main body 11a, and the tip of the detection unit 16a is located in the vicinity of the flow path B.

  The temperature sensor 16 is connected to a temperature control device (not shown) through wiring. The temperature control device adjusts the temperature of the thermoplastic resin R supplied to the press device 3 by controlling the flow of the cooling water pipe 14 and the energization of the cartridge heater 15 according to the temperature detected by the temperature sensor 16.

  As shown in FIGS. 6 to 8, a plurality of rectangular plates 17 whose upper and lower ends are embedded in the inner wall of the main body 11 a are arranged in the main body 11 a. The plurality of plates 17 extend along the flow direction T1. The plurality of plates 17 function as wall portions that form a plurality of flow paths B inside the main body portion 11a.

  The length of the plate 17 in the flow direction T1 is substantially the same as the length of the land portion 11. Here, the substantially same range includes, for example, the case where the length of the plate 17 is about 80% to 110% of the length of the land portion 11.

  The flow path B is formed by being surrounded by the upper inner wall 11d and the lower inner wall 11e in the main body 11a in addition to the plate 17. In this embodiment, the plate 17 is an inner wall of the flow path B in the lateral width direction of the land portion 11, and the upper inner wall 11 d and the lower inner wall 11 e are inner walls of the flow path B in the vertical width direction (height direction) of the land portion 11. is there. The plate 17 corresponds to a portion between the flow paths B among the wall portions forming the flow paths B.

  The shape of the cross section perpendicular to the flow direction T1 of the thermoplastic resin R in each flow path B is a vertically long rectangular shape. The short side (horizontal width) of the rectangular cross-sectional shape is preferably 1 mm or more and 3 mm or less, and from the viewpoint that a sufficient amount of the thermoplastic resin R can be supplied from the temperature adjusting die 6, the long side (vertical width). Is preferably 6 mm or more. Further, the long side is more preferably 10 mm or more, and further preferably 15 mm or more. Note that the positional relationship between the long side and the short side may be opposite to the positional relationship of the present embodiment.

  Further, the ratio L / H between the length L of the flow path B (the length in the flow direction T1) and the short side H in the cross-sectional shape is 50 or more from the viewpoint that the temperature can be accurately adjusted to a predetermined temperature. It is preferable. L / H is preferably 300 or less, more preferably 200 or less from the viewpoint that the land portion 11 does not become too large, the temperature adjusting die 6 can be easily attached, and can be attached even in a small space.

  The plate 17 is made of copper having a large thermal conductivity as compared with a general structural material such as iron constituting most of the temperature adjusting die 6. Specifically, the plate 17 is made of copper having a thermal conductivity of 180 W / m · K or more. Since the plate 17 is made of copper having a high thermal conductivity, the temperature adjustment by the cooling water pipe 14 and the cartridge heater 15 can be efficiently transmitted to the thermoplastic resin R.

  4-7, the confluence | merging exit part 12 of the temperature control die | dye 6 has the confluence | merging flow path C where the thermoplastic resin R extruded from the flow path B of the land part 11 merges. . The merging channel C is a curved channel having a downward outlet 12a. The flow direction of the thermoplastic resin R pushed out from the outlet 12a is indicated by an arrow T2. Note that a cutter mechanism for cutting off the molten thermoplastic resin R is preferably attached to the outlet 12a of the merging channel C.

  Two junction heater cartridge heaters 18 are arranged at the junction outlet portion 12. Two merge outlet cartridge heaters 18 are arranged so as to sandwich the merge channel C on the left and right sides, and heat the thermoplastic resin R flowing through the merge channel C. Further, a temperature sensor 19 having the same structure as the temperature sensor 16 of the land portion 11 is provided above the junction outlet portion 12.

  The temperature sensor 19 and the cartridge heater 18 are connected to the above-described temperature control device through wiring. When the temperature detected by the temperature sensor 19 is lower than the set temperature, the heat flowing through the merge channel C using the cartridge heater 18. The plastic resin R is heated.

  According to the temperature control die 6 configured in this way, the plate 17 forming the flow path B is made of copper having a thermal conductivity of 180 W / m · K or more, compared with the case of forming from iron. The heat conduction efficiency between the cooling water in the cooling water pipe 14 and the cartridge heater 15 and the thermoplastic resin R in the flow path B can be improved, and the temperature of the thermoplastic resin R can be adjusted efficiently. Therefore, according to the temperature adjusting die 6, the temperature of the thermoplastic resin R can be adjusted efficiently and the processing capacity is improved, so that the thermoplastic resin R having a desired temperature can be obtained in a short time. .

  The temperature control die having such a configuration is described in detail in Japanese Patent Application No. 2011-139559. Further, the configuration of the temperature adjusting die 6 is not limited to that described above. The plate 17 is not necessarily made of copper, and may be made of aluminum, gold, silver or the like instead of copper. Moreover, as long as heat conductivity is 180 W / m * K or more, you may be comprised from two or more types of materials. In addition, the board 17 may only contain copper etc. with high heat conductivity in part. In this case, the ratio of the material having high thermal conductivity in the surface area of the plate 17 is preferably 50% or more, and more preferably 70% or more. Furthermore, it is also possible to provide the plate 17 so as to divide the flow path B in the lateral direction or the oblique direction. Further, it is not always necessary to use the temperature adjusting die 6 in the manufacturing method according to the present invention.

  Next, the configuration of the press device 3 will be described. As shown in FIGS. 1 to 3, the press device 3 is a device that performs press molding with a pair of male and female dies 7. The mold 7 includes an upper mold 7a that is a movable mold and a lower mold 7b that is a fixed mold.

  A plurality of flow paths D through which the heating medium and the cooling medium flow are formed in the molds 7a and 7b. The channel D having a circular longitudinal section is formed to have a diameter of 3 to 10 mm, for example. For example, steam, pressurized water, hot water, or the like is used as the heating medium flowing through the flow path D, and cooling water or the like is used as the cooling medium.

  In the molds 7a and 7b, the heating medium and the cooling medium flow in the flow path D, whereby the temperature adjustment of the cavity surfaces Ca and Cb is realized. By using such dies 7a and 7b, rapid heating and cooling molding can be performed in which the temperatures of the cavity surfaces Ca and Cb (see FIG. 9) are changed in a short time.

  Rapid heating / cooling molding means that the temperature of the cavity surfaces Ca and Cb of the molds 7a and 7b is increased at the start of resin molding, and the temperature of the cavity surfaces Ca and Cb of the molds 7a and 7b is increased after completion of molding. This is a lowering molding method. Note that it is not always necessary to adjust the temperature of both the cavity surfaces Ca and Cb. For example, only a part of the cavity surface corresponding to the design surface of the resin molded body may be temperature adjusted.

  The press device 3 includes a drive source 8 for opening and closing the molds 7a and 7b. As the drive source 8, a hydraulic drive device or an electric drive device is employed. From the viewpoint of drive control, it is preferable to employ an electric drive device such as a servo motor.

  The pressing device 3 clamps the molds 7a and 7b by bringing the mold 7a closer to the mold 7b by the drive source 8. The relative speed between the molds 7a and 7b at this time is defined as a mold clamping speed. The press device 3 controls the mold clamping speed of the molds 7 a and 7 b by the drive source 8.

(Thermoplastic resin)
Examples of the thermoplastic resin R used in the present embodiment include polypropylene, polyethylene, acrylic resin, acrylonitrile-styrene-butadiene block copolymer, polyamide such as polystyrene and nylon, polyvinyl chloride, polycarbonate, and styrene-butadiene block copolymer. Examples thereof include thermoplastic elastomers such as coalescence, EPM and EPDM, mixtures thereof, polymer alloys using these, and crystalline resins such as polypropylene and polyethylene are preferable, and polypropylene is more preferable. Moreover, you may contain fillers, such as glass fiber, various inorganic fillers, and an organic filler, as needed. In the thermoplastic resin R of the present invention, a crystal melting peak is observed by differential scanning calorimetry (DSC). When the thermoplastic resin R used in the present invention is a mixture, any crystal melting peak may be observed by performing differential scanning calorimetry (DSC) of the mixture.

(Method for producing thermoplastic resin molding)
The method for producing a thermoplastic resin molded body according to the present embodiment includes a resin supply process and a shaping process. In the method for manufacturing a thermoplastic resin molded body according to the present embodiment, the cavity surfaces Ca and Cb of the molds 7a and 7b are preheated to the mold set temperature. The cavity surfaces Ca and Cb of the molds 7 a and 7 b are heated by flowing a heating medium in the flow path D. The mold set temperature is selected so that the temperatures of the cavity surfaces Ca and Cb at the start of shaping are within a predetermined temperature range. The temperature range of the cavity surfaces Ca and Cb at the start of shaping will be described later. In the method for manufacturing a thermoplastic resin molded body according to the present embodiment, the resin supply step is performed in a state where the cavity surfaces Ca and Cb of the molds 7a and 7b are heated to the mold set temperature.

<Resin supply process>
In the resin supply process, as shown in FIG. 2, the extruder 4 is moved to the press device 3 side by the moving mechanism 5, and is melted in the extruder 4 between the molds 7 a and 7 b in an open state. A predetermined amount of the thermoplastic resin R is supplied.

  In the resin supply step, the molten thermoplastic resin R is supplied through the temperature adjusting die 6 attached to the outlet of the melt plasticizing cylinder 4 c of the extruder 4. At this time, the temperature adjustment die 6 performs the temperature adjustment so that the temperature of the thermoplastic resin R flowing inside becomes the set temperature. The set temperature of the temperature adjusting die 6 is selected so that the resin temperature falls within a predetermined temperature range at the start of shaping. The temperature range at the start of shaping will be described later.

  Further, in the resin supplying step, the thickness of the molten thermoplastic resin R extruded from the temperature adjusting die 6 is a resin molded body to be manufactured from the viewpoint of increasing the rigidity and impact strength of the obtained molded body. The thickness is preferably 2 times or more and 10 times or less. In the resin supply step, the molten thermoplastic resin R is supplied between the pair of molds 7 a and 7 b through the temperature adjusting die 6, and the temperature of the molten thermoplastic resin R is adjusted in the temperature adjusting die 6. Thus, the resin temperature at the start of shaping can be adjusted in a short time, and the production efficiency of the thermoplastic resin molded product can be improved, which is preferable.

<Shaping process>
In the shaping step, the thermoplastic resin R is shaped by the press device 3 clamping the pair of male and female dies 7a and 7b. Here, Fig.9 (a) is a figure which shows the state of the thermoplastic resin R after a resin supply process. FIG.9 (b) is a figure which shows the state of the thermoplastic resin R at the time of a shaping start. FIG. 9C is a diagram showing a state of the thermoplastic resin R when the mold clamping is completed.

  From the state after the resin supply step shown in FIG. 9A, the molds 7a and 7b are closed to shift to the state of shaping start shown in FIG. 9B. It is preferable that the molds 7a and 7b start to close immediately after the resin supply step.

  In the shaping step of the present invention, when the shaping of the thermoplastic resin R shown in FIG. 9B is started, when both the male and female molds 7a and 7b are in contact with the thermoplastic resin R. equal. The molding of the thermoplastic resin R in press molding is started from the moment when the upper mold 7a is lowered and comes into contact with the thermoplastic resin R.

  Here, a value obtained by dividing the distance by which the upper mold 7a descends from the time when the upper mold 7a comes into contact with the thermoplastic resin R until the mold clamping of the molds 7a and 7b is completed is divided by the time between them. The clamping speed is V. In addition, the mold closing speed is distinguished from the mold clamping speed V as the speed at which the molds 7a and 7b are closed until the mold 7a comes into contact with the thermoplastic resin R from the fully opened position of the press.

  In this shaping step, the mold clamping speed V of the molds 7a and 7b is set as a speed greater than 30 mm / second and less than or equal to 500 mm / second. The mold clamping speed V is preferably set as a speed of 50 mm / second or more. The mold clamping speed V is preferably set as a speed of 300 mm / second or less.

  A mold clamping speed V of 50 mm / second or more is preferable because a molded body having a high rigidity and impact strength can be obtained with a small mold clamping force. When the mold clamping speed V is 300 mm / second or less, the impact force acting on the molds 7 a and 7 b when the mold is closed is reduced, and the molds 7 a and 7 b and the press device 3 are not easily damaged.

  In this shaping step, when shaping of the thermoplastic resin R shown in FIG. 9B is started, the temperature of the cavity surfaces Ca and Cb of the molds 7a and 7b is 30 from the deflection temperature under load of the thermoplastic resin R. As described above, the mold set temperature is adjusted so that the temperature is lower than the ° C. In addition, at the start of shaping of the thermoplastic resin R, only a part of the cavity surfaces Ca and Cb may be set to a temperature not lower than 30 ° C. lower than the deflection temperature under load of the thermoplastic resin R. Furthermore, the configuration for adjusting the temperatures of the cavity surfaces Ca and Cb of the molds 7a and 7b is not limited to the one provided with the flow path D. For example, the structure which heats metal mold | die 7a, 7b with an electric heater, a high frequency induction heating apparatus, etc. may be sufficient.

  In this shaping step, the temperature of the molten thermoplastic resin when shaping of the thermoplastic resin R shown in FIG. 9B is started is 20 ° C. lower than the melting point of the thermoplastic resin R, and more than the melting point. The temperature is 10 ° C. or higher. The resin temperature at this time is preferably at least 10 ° C. below the melting point and below 10 ° C. above the melting point. More preferably, the temperature is 10 ° C. lower than the melting point and lower than the melting point. If the temperature of the molten thermoplastic resin R at the start of shaping is 20 ° C. lower than the melting point of the thermoplastic resin R, the resin has good fluidity and is shaped according to the cavity shape of the mold 7. can do. When the temperature of the thermoplastic resin R is 10 ° C. or lower than the melting point, a thermoplastic resin molded article Rc having high rigidity and impact strength can be obtained. Adjustment of the resin temperature at the start of shaping is performed by adjusting the resin temperature at the time of supply by the temperature adjusting die 6.

  Thereafter, in the shaping step, the molds 7a and 7b are clamped to spread the thermoplastic resin R along the cavity surfaces Ca and Cb, and the shaping of the thermoplastic resin R proceeds. In the present embodiment, since the cavity shape of the mold 7b is a three-dimensional shape having a vertical wall portion at the terminal portion, the thermoplastic resin R in the cavity has a three-dimensional shape having an uneven portion which is a vertical wall portion. Shaped. When the mold clamping of the thermoplastic resin R is completed, the state shown in FIG.

  In the state of FIG. 9C, the thermoplastic resin R is cooled. At this time, in the molds 7a and 7b, the temperature of the cavity surfaces Ca and Cb is lowered as the cooling medium flows through the flow path D. For example, the cavity surfaces Ca and Cb are cooled so as to have a temperature of 20 ° C. to 60 ° C. Thereafter, the cooled thermoplastic resin R is solidified to form a thermoplastic resin molded body Rc having a vertical wall portion.

《Release process》
In the mold release step, the molds 7a and 7b are opened, and the internal resin molded body Rc is taken out. FIG. 10 shows the state of the thermoplastic resin molded body Rc after the mold release step. In the mold release step, the molds 7a and 7b are first opened at a moderate speed, and then the mold is opened at a high speed up to a position where the molds are opened. Thereafter, the molded thermoplastic resin molded body Rc is taken out from the mold 7b.

  In addition, the manufacturing method according to the present embodiment uses a three-dimensional resin molded body having uneven portions and a resin molded body having an average thickness of 1 mm or more, as compared with the case of manufacturing a sheet-like thin resin molded body. This is particularly effective when manufacturing. In addition, the three-dimensional resin molded body having the concavo-convex portion is manufactured by using a mold having a cavity shape having a three-dimensional shape having the concavo-convex portion as in the present embodiment, for example. Moreover, it is preferable that the average thickness of a resin molding is 5 mm or less from a viewpoint of obtaining a resin molding with high rigidity and impact strength.

  The method for producing a thermoplastic resin molded body according to the present invention can also be used in injection press molding using an injection machine. In this case, the injection machine corresponds to a melt plasticizer.

  Here, FIG. 11 shows another example of a mold that can be used in the method for producing a thermoplastic resin molded body according to the present invention. The cavity shape formed by the mold 20 shown in FIG. 11 also has a three-dimensional shape having concavo-convex portions as in the mold 7 described above. In addition, although the metal mold | die 20 has two uneven | corrugated | grooved parts located in the edge part on either side of a cavity surface, when the uneven | corrugated | grooved part is one place or three or more places, the cavity shape has an uneven | corrugated | grooved part. Included when it has a three-dimensional shape.

Example 1
As Example 1, the manufacturing method of the thermoplastic resin molding which concerns on embodiment mentioned above was performed. As thermoplastic resin R, polypropylene (trade name: Sumitomo Nobrene H501, manufactured by Sumitomo Chemical Co., Ltd., MFR = 3 g / 10 min, melting point 165 ° C., deflection temperature under load 142 ° C.) is used, and a resin molding having a thickness of 2.5 mm is used. The body was manufactured.

As the injection machine, an injection apparatus for SLIM10e16 (manufactured by Sato Iron Works Co., Ltd., maximum clamping force 980 kN, theoretical injection capacity 1610 cc) was used, and as the pressing apparatus, a clamping apparatus for SLIM10e16 was used.
The mold used is a pair of male and female press molds consisting of an upper movable mold and a lower fixed mold, and has a substantially flat plate shape with 400 mm in length, 600 mm in width, 60 mm in height, and has a texture on the surface. Was used. A high frequency induction heating device with a high frequency oscillation frequency of 20 kHz and a high frequency output of 50 kW is installed outside the mold for heating the mold, and the upper movable mold cavity surface is heated in advance before supplying molten polypropylene between the molds. I was able to do it.
Further, the temperature adjusting die 6 according to the embodiment described above was attached to the outlet of the injection machine. The temperature of the injector was set to 200 ° C. Polypropylene was introduced into the injection machine and melted, and the molten polypropylene was supplied between the dies through the temperature control die 6.
Thereafter, the mold clamping speed of the press apparatus was set to 70 mm / second and shaping was started.
At this time, before the molten polypropylene was supplied between the molds so that the temperature of the mold cavity surface at the start of shaping was 120 ° C., the surface of the movable mold cavity was heated in advance by a high-frequency induction heating device. The temperature of the temperature adjusting die 6 was set so that the temperature of the molten polypropylene at the start of shaping was 165 ° C.

(Comparative Example 1)
It was produced in the same manner as in Example 1 except that the surface of the movable mold cavity was not heated in advance before supplying the molten polypropylene between the molds.

(Comparative Example 2)
It was manufactured in the same manner as in Example 1 except that the temperature at the start of shaping was 200 ° C.

[Evaluation method]
(1) Flexural modulus The flexural modulus of the molded bodies produced in the examples and comparative examples was measured under the following conditions in accordance with JIS K7203.
Measurement temperature: 23 ° C
Span: 50mm
Bending speed: 2 mm / min (2) Impact strength The impact strength of the molded bodies produced in the examples and comparative examples was measured according to JIS K7110 under the following conditions.
Measurement temperature: 23 ° C
(3) Gloss with V notch Gloss on the surface of the molded body produced in Examples and Comparative Examples was measured according to JIS Z8741 under the following conditions. If the gloss value is 1.8 or less, the transferability is good and the appearance is good.
Measurement angle: 60 °
(4) Melting point (unit: ° C)
The melting points of the thermoplastic resins used in the examples and comparative examples were measured using a suggested scanning calorimeter (DSC VII manufactured by Perkin Elmer). Measurement conditions were such that 10 mg of a specimen was previously placed in a nitrogen atmosphere and melted at 220 ° C. for 5 minutes, and then cooled to 50 ° C. at a rate of 5 ° C./min for crystallization. Thereafter, the temperature was raised at 5 ° C./min, and the temperature of the maximum peak of the obtained melting endothermic curve was taken as the melting point.
(5) Melt flow rate (MFR, unit: g / 10 min)
The MFR of the thermoplastic resin used in Examples and Comparative Examples was measured according to JIS-K7210 under the following conditions.
Measurement temperature: 230 ° C
Load: 2.16kgf
(6) Deflection temperature under load (unit: ° C)
The deflection temperature under load of the thermoplastic resins used in Examples and Comparative Examples was measured according to JIS-K7191-2B method.
(7) Movable cavity surface temperature at the start of shaping (unit: ° C)
In Example, the time from the completion of heating of the movable cavity surface to the start of shaping was measured, and the time was set to t1 seconds.
Apart from the production of the thermoplastic resin molded body in the examples, the temperature of the movable cavity surface at the start of shaping was measured. A thermocouple is attached to the movable cavity surface, the movable cavity surface is heated for a predetermined time using a high-frequency induction heating device, and the temperature of the mold cavity surface is measured after t1 seconds after the heating is completed. did. The same measurement was performed by changing the heating time with the high-frequency induction heating device, and in the above-described examples and comparative examples, the heating time at which the movable cavity surface temperature at the start of shaping could be set to a desired temperature was obtained. .
(8) Temperature at the start of shaping (unit: ° C)
Apart from the production of the thermoplastic resin molded body in the examples, the temperature of the molten polypropylene at the start of shaping was measured. In advance, in the examples, the time from the supply of molten polypropylene between the molds to the start of shaping was measured, and the time was t2 seconds.
A temperature control die 6 was attached to the tip of the SLIM 10e16 injection device, the temperature of the injection device was set to 200 ° C., and molten polypropylene was supplied between the molds through the temperature control die 6 set to a predetermined temperature. The resin temperature was measured by inserting a thermocouple into the central part of the molten polypropylene (substantially central part in the length direction and the thickness direction) on the mold cavity surface t2 seconds after the supply of the molten polypropylene was completed.
The same measurement is performed by changing the set temperature of the temperature adjusting die 6, and the set temperature of the temperature adjusting die 6 can be set to a desired temperature at the start of shaping in the above-described embodiments and comparative examples. Asked.

DESCRIPTION OF SYMBOLS 1 ... Molding apparatus 2 ... Resin supply apparatus 3 ... Press apparatus 4 ... Extruder (melt plasticizing apparatus) 5 ... Movement mechanism 6 ... Die for temperature control 7, 7a, 7b ... Mold 8 ... Drive source 10 ... Inlet part 11 ... Land part 11a ... Main body part 11b, 11c ... Side guide 12 ... Merging outlet part 14 ... Cooling water piping 15 ... Cartridge heater 16 ... Temperature sensor 17 ... Plate 18 ... Merging outlet part cartridge heater 19 ... Temperature sensor 20, 20a, 20b ... Mold A ... Inlet channel B ... Channel C ... Merge channel D ... Channel Ca, Cb ... Cavity surface R ... Thermoplastic resin Rc ... Thermoplastic resin molding T1 ... Flow direction T2 ... Flow direction

Claims (4)

A thermoplastic resin molded body comprising a resin supply step of supplying a molten thermoplastic resin between a pair of molds, and a shaping step of shaping the thermoplastic resin by clamping the pair of molds A manufacturing method of
When shaping of the thermoplastic resin is started in the shaping step, the temperature of at least a part of the cavity surface of the mold corresponding to the design surface side of the thermoplastic resin molded body is a deflection of the load of the thermoplastic resin. A temperature that is 30 ° C. lower than the temperature,
The temperature of the thermoplastic resin when the shaping of the thermoplastic resin is started is a temperature that is 20 ° C. lower than the melting point of the thermoplastic resin, and a temperature that is 10 ° C. higher than the melting point,
The method for producing a thermoplastic resin molded body, wherein a mold clamping speed in the shaping step is greater than 30 mm / second and 500 mm / second or less.   In the resin supplying step, a molten thermoplastic resin is supplied between the pair of molds through a temperature adjusting die attached to an outlet of a melt plasticizing apparatus that melts the thermoplastic resin. In the temperature adjusting die, The method for producing a thermoplastic resin molded article according to claim 1, wherein the temperature of the molten thermoplastic resin is adjusted.   The method for producing a thermoplastic resin molded body according to any one of claims 1 and 2, wherein a cavity shape formed by the pair of molds is a three-dimensional shape having an uneven portion. The said shaping process is a process of shaping the said thermoplastic resin in the shape which has an average thickness of 1 mm or more and 5 mm or less, The manufacture of the thermoplastic resin molding as described in any one of Claims 1-3. Method.

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