JP2006056214A - Resin sheet manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin sheet manufacturing method capable of obtaining a desired cross-sectional shape when a resin sheet large in the thickness distribution in its width direction at molding is manufactured and manufacturing the resin sheet especially suitable for use in the light guide plate or various optical elements arranged on the back of various display devices. <P>SOLUTION: The sheetlike resin material 14 extruded from a die 12 is held under pressure by a mold roller 16 and the nip rollers 18, 20 and 22 arranged in opposed relation to the mold roller and the uneven shape on the surface of the mold roller is transferred to a resin material. Then, the resin material is wound around the peeling roller 24 arranged in opposed relation to the mold roller to be peeled from the mold roller. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a resin sheet, and more particularly to a method for producing a resin sheet suitable for use in a light guide plate and various optical elements disposed on the back surface of various display devices.

  As resin sheets used for various optical elements, Fresnel lenses, lenticular lenses, and the like are used in various fields. A regular uneven shape is formed on the surface of such a resin sheet, and this uneven shape exhibits optical performance as a Fresnel lens or a lenticular lens.

  As a method for producing such a resin sheet, various proposals have been made so far (see Patent Documents 1 to 4). In these proposals, the roller molding method is adopted from the viewpoint of improving productivity.

  For example, Patent Document 1 attempts to improve transferability by devising the cooling means until the resin sheet is peeled from the roller. Patent Document 2 discloses a method of manufacturing a Fresnel lens by winding a die around a roller.

  In Patent Document 3, a heat buffer member is arranged inside the forming roller to improve productivity and transferability. Patent Document 4 uses a corona discharge treatment to improve transferability and reduce defects.

  A typical roller forming system of these prior arts has a configuration shown in FIG. This apparatus configuration includes a sheet die 2 for shaping a resin material 1 melted by an extruder (not shown) into a sheet shape, a stamper roller 3 having an uneven surface formed thereon, and a stamper roller 3. And a mirror roller 4 for peeling, which is disposed opposite to the mirror roller 4 while facing the stamper roller 3.

Then, the sheet-like resin material 1 extruded from the die 2 is pressed between the stamper roller 3 and the mirror roller 4, and the uneven shape on the surface of the stamper roller 3 is transferred to the resin material 1, and the resin material 1 is peeled off by the mirror roller for peeling. 5 is peeled off from the stamper roller 3 by being wound around.
JP-A-8-31025 JP-A-7-314567 JP 2003-53834 A JP-A-8-287530

  However, any of the above conventional proposals relates to a method for producing a relatively thin resin sheet, and is not suitable for producing a relatively thick resin sheet. In particular, when a resin sheet having a large thickness distribution in the width direction during molding is produced, it is very difficult to obtain a desired cross-sectional shape.

  For example, when PMMA (polymethylmethacrylate resin) is extruded and then subjected to roller molding, when the thickness distribution is given in the width direction and the difference in thickness between the thickest part and the thinnest part is 1 mm or more, the surface or There are various problems such as unevenness on the back surface (shrinkage due to shrinkage when the resin is cured, distribution of elastic recovery amount), overall surface shape transfer rate is reduced, and sharp edge shape cannot be transferred.

  The present invention has been made in view of such circumstances. When a resin sheet having a large thickness distribution in the width direction at the time of molding is produced, a desired cross-sectional shape can be obtained. It aims at providing the manufacturing method of the resin sheet suitable for using for the light-guide plate and various optical elements which are distribute | arranged to a back surface.

  In order to achieve the above-mentioned object, the present invention presses a sheet-shaped resin material extruded from a die with a mold roller and a plurality of nip rollers arranged to face the mold roller, and forms the uneven shape on the surface of the mold roller. There is provided a method for producing a resin sheet, wherein the resin material is transferred to a resin material, and the transferred resin material is peeled off from the mold roller by winding the resin material on a release roller disposed opposite to the mold roller.

  According to the present invention, the sheet-shaped resin material is pinched by the mold roller and the plurality of nip rollers, the concavo-convex shape is transferred to the resin material, and the resin material is wound around the peeling roller to be peeled off from the mold roller. In this way, by using a plurality of nip rollers arranged to face the mold roller, the back surface unevenness generated immediately after molding at the first nip point is a resin sheet having a large thickness distribution in the width direction during molding. Even if this occurs, it is possible to obtain a desired cross-sectional shape by suppressing the deformation due to the downstream roll wrapping (winding) by re-correcting this or by cooling and fixing at an early stage in that state.

  In the present invention, it is preferable that the difference in thickness between the thickest portion and the thinnest portion in the width direction of the resin material is 1 mm or more due to the uneven shape transferred to the resin material. Moreover, in this invention, it is preferable that the thickness of the thinnest part of the said resin material is 5 mm or less. Thus, the effect of the present invention can be exhibited in the molding of a resin material having a cross-sectional shape that has been difficult to mold.

  In the present invention, it is preferable that a belt-shaped member is supplied between the mold roller and the plurality of nip rollers and / or the peeling roller, and the resin material is sandwiched between the belt-shaped member and the mold roller. . As described above, by adopting the belt-shaped member, the distance for pressing the resin material can be increased, and a desired cross-sectional shape can be easily obtained.

  As described above, according to the present invention, a desired cross-sectional shape can be obtained even with a resin sheet having a large thickness distribution in the width direction during molding.

  Hereinafter, a preferred embodiment (first embodiment) of a method for producing a resin sheet according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing an example of a resin sheet production line to which a resin sheet production method according to the present invention is applied.

  This resin sheet production line 10 includes a sheet die 12 for shaping a resin material 14 melted by an extruder (not shown) into a sheet shape, and a mold roller 16 having an uneven surface formed on the surface. A plurality of nip rollers (first nip roller 18, second nip roller 20, and third nip roller 22) disposed opposite to the mold roller 16, a peeling roller 24 disposed opposite to the mold roller 16, and cooling devices 26, 28. And the slow cooling zone 30.

  The slit size of the die 12 is formed so that the width of the molded molten resin material 14 is wider than the width of the mold roller 16, and the molten resin material 14 extruded from the die 12 is formed with the first roller 16 and the first roller 12. It arrange | positions so that it may extrude between the nip rollers 18. FIG.

  A regular uneven shape is formed on the surface of the mold roller 16. This regular uneven | corrugated shape can be made into the inversion shape of the resin material 14 after a shaping | molding shown by FIG. 2, for example. FIG. 2 is a perspective view of a state in which the end surface 14A of the resin material 14 after molding is cut out on a straight line.

  That is, the back surface of the resin material 14 is a flat surface, and a linear uneven pattern parallel to the arrow is formed on the surface of the resin material 14. This arrow indicates the traveling direction of the resin material 14. Therefore, an endless groove having an inverted shape of the end face 14 </ b> A may be formed on the surface of the mold roller 16. The details of the uneven pattern shape on the surface of the resin material 14 will be described later.

  The material of the mold roller 16 includes various steel members, stainless steel, copper, zinc, brass, and a metal lining of these metal materials, and a rubber lining on the surface. These metal materials are HCr plated, Cu plated, Ni plated. For example, ceramics and various composite materials can be used.

  The method for forming the concavo-convex pattern on the surface of the mold roller 16 depends on the concavo-convex pattern (pitch, depth, etc.) and the material of the surface of the mold roller 16, but generally a combination of cutting with an NC lathe and finishing buffing. Can be preferably employed. In addition, other known processing methods (grinding processing, ultrasonic processing, electric discharge processing, etc.) can also be employed.

  The surface roughness of the surface of the mold roller 16 is preferably 0.5 μm or less in Ra, and more preferably 0.2 μm or less.

  The mold roller 16 is driven to rotate in a direction indicated by an arrow in FIG. 1 at a predetermined peripheral speed by a driving means (not shown). The mold roller 16 is provided with temperature adjusting means. By providing such a temperature adjusting means, it is possible to control to suppress the temperature rise or sudden temperature drop of the mold roller 16 due to the resin material 14 in a high temperature state.

  As such temperature adjusting means, a configuration in which oil whose temperature is adjusted is circulated inside the roller can be preferably employed. This supply and discharge of oil can be realized by a configuration in which a rotary joint is provided at the end of the roller. In the resin sheet production line 10 of FIG. 1, this temperature adjusting means is employed.

  The nip roller is disposed opposite to the mold roller 16 and presses the resin material 14 with the mold roller 16. The first nip roller 18, the second nip roller 20, and the third nip roller 22 are arranged in this order from the upstream side in the running direction. Is arranged in.

  The surfaces of the nip rollers 18, 20, and 22 are preferably processed into a mirror surface. By setting it as such a surface, the back surface of the resin material 14 after shaping | molding can be made into a favorable state. The surface roughness of the nip rollers 18, 20, and 22 is preferably 0.5 μm or less in Ra, and more preferably 0.2 μm or less.

  The materials of the nip rollers 18, 20, and 22 are various steel members, stainless steel, copper, zinc, brass, those metal materials as a core metal, and a rubber lining on the surface. These metal materials are HCr plated, Cu plated. Ni-plated or other plated materials, ceramics, and various composite materials can be used.

  Each of the nip rollers 18, 20, and 22 is rotationally driven in a direction indicated by an arrow in FIG. 1 at a predetermined peripheral speed by a driving unit (not shown). In addition, although the structure which does not provide a drive means in the nip rollers 18, 20, and 22 is also possible, it is preferable to provide a drive means from the point which can make the back surface of the resin material 14 a favorable state.

  In the case where the driving means is provided in the nip rollers 18, 20, and 22, a configuration in which the respective driving speeds can be preferably adopted. Accordingly, for example, an operation method in which the nip rollers 18, 20, and 22 are gradually increased from the peripheral speed of the die roller 16 in the order of the nip rollers 18, 20, and 22 (at most within a range of several%) can be employed.

  Each of the nip rollers 18, 20, and 22 is provided with a pressure unit (not shown) so that the resin material 14 between the nip rollers 18, 20, and 22 can be clamped with a predetermined pressure. These pressurizing means are all configured to apply pressure in the normal direction at the contact point between the nip rollers 18, 20, 22 and the mold roller 16, and are known in the art such as motor drive means, air cylinders, hydraulic cylinders, etc. Various means can be adopted.

  The nip rollers 18, 20, and 22 may be configured to be less likely to bend due to the reaction force of the clamping pressure. As such a configuration, a configuration in which a backup roller is provided on the back side of the nip rollers 18, 20, and 22 (opposite side of the mold roller 16), a configuration in which a crown shape (middle and high shape) is adopted, and a central portion in the axial direction of the roller A configuration of a roller having a strength distribution that increases the rigidity of the roller, a configuration combining these, and the like can be employed.

  The nip rollers 18, 20, and 22 are all provided with temperature adjusting means. The respective roller set temperatures of the first nip roller 18, the second nip roller 20, and the third nip roller 22 are the material of the resin material 14, the temperature when the resin material 14 is melted (for example, the slit exit of the die 12), The optimum value should be selected according to the conveying speed, the outer diameter of the mold roller 16, the uneven pattern shape of the mold roller 16, and the like.

  As each roller temperature adjusting means of the first nip roller 18, the second nip roller 20, and the third nip roller 22, a configuration in which oil whose temperature is adjusted is circulated inside the rollers can be preferably employed. This supply and discharge of oil can be realized by a configuration in which a rotary joint is provided at the end of the roller. In the resin sheet production line 10 of FIG. 1, this temperature adjusting means is employed.

  As other temperature adjusting means, for example, various known means such as a structure in which a sheath heater is embedded in the roller and a structure in which a dielectric heating means is disposed in the vicinity of the roller can be adopted.

  Further, in the resin sheet production line 10 of FIG. 1, cooling devices 26 and 28 are provided to assist temperature adjusting means of the first nip roller 18, the second nip roller 20, and the third nip roller 22. Yes.

  The cooling devices 26 and 28 are both air nozzles, and the air nozzles of the cooling device 26 are arranged so that air is blown to the resin material 14 being conveyed through the gap between the second nip roller 20 and the third nip roller 22. The air nozzle of the cooling device 26 is arranged so that air is blown onto the third nip roller 22. In this way, the temperature of the resin material 14 can be directly controlled, and the temperature of the resin material 14 can be controlled via the third nip roller 22.

  The air temperature and air supply amount (spraying flow rate) of the cooling devices 26 and 28 are the material of the resin material 14, the temperature when the resin material 14 is melted (for example, the slit exit of the die 12), the transport speed of the resin material 14, the mold The optimum value should be selected according to the outer diameter of the roller 16, the uneven pattern shape of the mold roller 16, the set temperatures of the nip rollers (the first nip roller 18, the second nip roller 20, and the third nip roller 22).

  The peeling roller 24 is disposed opposite to the mold roller 16 and is a roller for peeling the resin material 14 from the mold roller 16 by winding the resin material 14, and 180 degrees downstream of the first nip roller 18 with the mold roller 16 interposed therebetween. Arranged on the side.

  The surface of the peeling roller 24 is preferably processed into a mirror surface. By setting it as such a surface, the back surface of the resin material 14 after shaping | molding can be made into a favorable state. The surface roughness of the surface of the peeling roller 24 is preferably 0.5 μm or less in terms of Ra, and more preferably 0.2 μm or less.

  As the material of the peeling roller 24, various steel members, stainless steel, copper, zinc, brass, these metal materials having a metal core and a rubber lining on the surface, these metal materials are HCr plated, Cu plated, Ni plated For example, ceramics and various composite materials can be used.

  The peeling roller 24 is driven to rotate in the direction of the arrow in FIG. 1 by a driving means (not shown) at a predetermined peripheral speed. In addition, although the structure which does not provide a drive means in the peeling roller 24 is also possible, it is preferable to provide a drive means from the point which can make the back surface of the resin material 14 a favorable state.

  The peeling roller 24 is provided with temperature adjusting means. And the uneven | corrugated pattern shape of the surface of the resin material 14 can be made favorable by setting it as appropriate setting temperature.

  It is preferable to provide surface temperature measuring means (not shown) so that the surface temperatures of the respective rollers and the resin material 14 described above can be monitored. As such surface temperature measuring means, various known measuring means such as an infrared thermometer and a radiation thermometer can be employed.

  As the measurement points by such surface temperature measuring means, for example, a plurality of points in the width direction of the resin material 14 between the die 12 and the first nip roller 18 and a plurality of points in the width direction of the resin material 14 immediately after the peeling roller 24 are used. The surface of the resin material 14 currently wound around the point | piece roller 16 or the peeling roller 24 in the width direction (the opposite surface side of a roller) etc. can be considered.

  In addition, the monitoring result of the surface temperature measuring means can be fed back to the temperature adjusting means of each roller, the die 12, etc. and reflected in the temperature control of each roller. It is also possible to operate by feedforward control without providing the surface temperature measuring means.

  A tension detecting means for detecting the tension of the resin material 14 or a plate thickness detecting means (thickness sensor) for detecting the thickness of the resin material 14 is provided on the resin sheet production line 10 in FIG. It can also be preferably adopted. Moreover, the detection result by such a detection means can be compared with a set value and fed back to a draw control described later.

  The slow cooling zone 30 (or annealing zone) is provided to prevent a rapid temperature change of the resin material 14 downstream of the peeling roller 24. When a sudden temperature change occurs in the resin material 14, for example, the inside of the resin material 14 is in an elastic state while the vicinity of the surface of the resin material 14 is in a plastic state. The surface shape of the material 14 deteriorates. In addition, there is a problem that a temperature difference occurs between the front and back surfaces of the resin material 14 and the resin material 14 is warped.

  As the slow cooling zone 30, it is possible to adopt a configuration in which a horizontal tunnel shape is provided, temperature adjusting means is provided inside the tunnel, and the cooling temperature profile of the resin material 14 can be controlled. As the temperature adjusting means, a structure in which air (hot air or cold air) whose temperature is controlled from a plurality of nozzles is ejected toward the resin material 14, and heating means (nichrome wire heater, infrared heater, dielectric heating means, etc.) Various known means such as a structure for heating the front and back surfaces of the material 14 can be employed.

  Downstream of the slow cooling zone 30 (or annealing zone), a cleaning device (cleaning zone), a defect inspection device (inspection zone), a laminating device, a side cutter, a cross cutter, and a stacking unit are sequentially provided.

  Among these, the laminating apparatus is an apparatus that attaches a protective film (a film such as polyethylene) to the front and back surfaces of the resin material 14, and the side cutter is an apparatus that cuts off both end portions (discarded portions) of the resin material 14 in the width direction. The cross cutter is a device that cuts the resin material 14 to a predetermined length.

  Some of the above devices may be omitted depending on the application.

  Next, a method for producing a resin sheet by the resin sheet production line 10 shown in FIG. 1 will be described.

  As the resin material 14 applied to the present invention, a thermoplastic resin can be used. For example, polymethyl methacrylate resin (PMMA), polycarbonate resin, polystyrene resin, MS resin, AS resin, polypropylene resin, polyethylene resin, polyethylene Examples include terephthalate resins, polyvinyl chloride resins (PVC), thermoplastic elastomers, copolymers thereof, and cycloolefin polymers.

  The sheet-shaped resin material 14 extruded from the die 12 is sandwiched between the mold roller 16 and a plurality of nip rollers (first nip roller 18, second nip roller 20, and third nip roller 22) disposed to face the mold roller 16. The uneven shape on the surface of the mold roller 16 is transferred to the resin material 14, and the resin material 14 is peeled off from the mold roller 16 by being wound around a peeling roller 24 disposed to face the mold roller 16.

  The resin material 14 peeled off from the mold roller 16 is transported in the horizontal direction, gradually cooled by passing through the slow cooling zone 30, and cut into a predetermined length in the downstream product removing portion in a state where distortion is removed. And accommodate as a resin sheet product.

  In the production of this resin sheet, the extrusion speed of the resin material 14 from the die 12 can be 0.1 to 50 m / min, preferably 0.3 to 30 m / min. Accordingly, the peripheral speed of the mold roller 16 is also substantially matched with this.

  On the other hand, the driving of the nip rollers (the first nip roller 18, the second nip roller 20, and the third nip roller 22) is a so-called draw control in which the nip rollers 18, 20, 22 are gradually increased from the peripheral speed of the mold roller 16 in this order. The driving method. The draw value between the nip rollers 18, 20, and 22 is preferably 0 to 3%, and more preferably 0 to 1%.

  It should be noted that the speed unevenness of each roller is preferably controlled to be within 1% of the set value.

  The pressing pressure of each nip roller (the first nip roller 18, the second nip roller 20, and the third nip roller 22) to the mold roller 16 is converted into a linear pressure (on the assumption that surface contact due to elastic deformation of each nip roller is a line contact). Value) is preferably 0 to 200 kN / m (0 to 200 kgf / cm), and more preferably 0 to 100 kN / m (0 to 100 kgf / cm).

  The temperature control of the nip rollers 18, 20, 22 and the peeling roller 24 is preferably performed for each individual roller. And it is preferable that the resin material 14 in the location of the peeling roller 24 is the temperature below the softening point Ta of resin. At this time, when a polymethylmethacrylate resin is used as the resin material 14, the set temperature of the peeling roller 24 can be 50 to 110 ° C.

  Next, details of the uneven pattern shape on the surface of the resin material 14 will be described. As described above, FIG. 2 is a perspective view showing a state in which the end surface 14A of the molded resin material 14 is cut out on a straight line. The back surface of the resin material 14 is a flat surface.

  The uneven pattern shape on the surface of the resin material 14 is a linear uneven pattern in the longitudinal direction (the arrow direction in the figure). In this pattern, the V-groove 50 formed in the thickest part 14B of the resin material 14 and the plate thickness decreases linearly from both edges of the V-groove 50 toward the thinnest part 14C of the resin material 14. The taper portions 52 and 52 are repeatedly shaped. That is, it is a continuous shape in which the V groove 50 and the taper portions 52 and 52 on both sides, which are line targets with respect to the center line of the V groove 50, are one unit (one pitch).

  In FIG. 2, the thickness of the thinnest portion 14C of the resin material 14 is preferably 5 mm or less, and more preferably 2 mm or less. The difference in thickness between the thickest part 14B and the thinnest part 14C of the resin material 14 is preferably 1 mm or more, and more preferably 2.5 mm or more. By setting it as such a dimension, it can be used conveniently for the light-guide plate and various optical elements which are distribute | arranged to the back surface of various display apparatuses.

  When the molded resin material 14 is used for the light guide plate, a cylindrical cold cathode tube is arranged inside the V groove 50, and light irradiated from the cold cathode tube is resin from the surface of the V groove 50. The light enters the inside of the material 14, is reflected by the tapered portions 52 and 52, and is irradiated in a planar shape from the back surface of the resin material 14.

  Thus, when using the resin material 14 after shaping | molding for a light-guide plate, it is preferable to make the width | variety p of V-groove 50 into 2 mm or more, and to make apex angle (theta) 1 of V-groove 50 into 40-80 degree | times. preferable. The depth Δt of the V groove 50 is preferably 1 mm or more, and more preferably 2.5 mm or more. The inclination angle θ2 of the tapered portions 52, 52 is preferably 3 to 20 degrees. Further, the width p2 of the tapered portions 52, 52 is preferably 5 mm or more, and more preferably 10 mm or more.

  Next, another uneven pattern shape on the surface of the resin material 14 will be described. FIG. 3 is a perspective view of a state in which the end surface 14A of the resin material 14 after molding is cut out on a straight line. The back surface of the resin material 14 is a flat surface.

  The uneven pattern shape on the surface of the resin material 14 is a linear uneven pattern in the longitudinal direction (the arrow direction in the figure). The cross-sectionally saw-tooth pattern has a vertical wall 54 that connects the thickest portion 14B and the thinnest portion 14C of the resin material 14 and the upper edge (thickest portion 14B) of the vertical wall 54. The taper portion 56 whose thickness decreases linearly toward the thinnest portion 14C is repeated.

  In FIG. 3, the thickness of the thinnest portion 14C of the resin material 14 is preferably 5 mm or less, and more preferably 2 mm or more. The difference in thickness between the thickest part 14B and the thinnest part 14C of the resin material 14 is preferably 1 mm or more, and more preferably 2.5 mm or more. By setting it as such a dimension, it can be used conveniently for the light-guide plate and various optical elements which are distribute | arranged to the back surface of various display apparatuses.

  When the molded resin material 14 is used for the light guide plate, a cylindrical cold cathode tube is disposed on the side surface of the vertical wall 54, and the light beam irradiated from the cold cathode tube is irradiated on the surface (side surface) of the vertical wall 54. ) Is incident on the inside of the resin material 14, is reflected by the taper portion 56, and is irradiated in a planar shape from the back surface of the resin material 14.

  Thus, when using the resin material 14 after shaping | molding for a light-guide plate, it is preferable that the taper part 56 inclination-angle (theta) 3 shall be 3-20 degree | times.

  In addition, when using the resin material 14 after shaping | molding for a light-guide plate, shapes other than these can also be employ | adopted. For example, the cross-sectional shape of the V-groove 50 of the resin material 14 in FIG. 2 is V-shaped, but other shapes such as a rectangular shape, a trapezoidal shape, an arc shape, a parabolic shape, etc. are also possible. It can be used if it satisfies the required characteristics and formability.

  Further, the uneven shape on the surface of the mold roller 16 does not need to be the inverted shape of the surface of the resin material 14 in FIG. 2 or 3, and the product shape of the resin material 14 is illustrated in consideration of the shrinkage allowance of the resin material 14. It can also be set as the shape offset from this shape so that it may become the shape of 2 or FIG.

  Next, another embodiment (second embodiment) of the method for producing a resin sheet according to the present invention will be described in detail. FIG. 4 is a configuration diagram showing a resin sheet production line 10 ′ to which the resin sheet production method according to the present invention is applied. In addition, the same code | symbol is attached | subjected about the member similar to 1st Embodiment shown by FIG. 1, and the description is abbreviate | omitted.

  In this embodiment, instead of the nip rollers (first nip roller 18, second nip roller 20, and third nip roller 22) and peeling roller 24 of the first embodiment, a nip belt 32 and a plurality of press rollers 34, 36, 38, 40 and guide rollers 42 and 44 are used.

  In the resin sheet production line 10 ′, the first press roller 34, the second press roller 36, the third press roller 38, and the fourth press roller 40 are the first in the resin sheet production line 10 (first embodiment). They are arranged at positions corresponding to the nip roller 18, the second nip roller 20, the third nip roller 22, and the peeling roller 24, respectively, and perform substantially the same function.

  However, since the resin material 14 is clamped by the nip belt 32 and the mold roller 16 which are endless belts, the clamping distance can be increased and a desired cross-sectional shape can be easily obtained.

  The surface of the nip belt 32 is preferably processed into a mirror surface. By setting it as such a surface, the back surface of the resin material 14 after shaping | molding can be made into a favorable state. The surface roughness of the surface of the nip belt 32 is preferably 0.5 μm or less in Ra, and more preferably 0.2 μm or less.

  The material of the nip belt 32 includes various steel members, stainless steel, rubber-lined surfaces of these metal materials, those plated with HCr plating, Cu plating, Ni plating, etc. The composite material can be adopted.

  As described above, the press rollers 34, 36, 38, and 40 exhibit the same function as the nip rollers of the first embodiment, so that the drive means is provided, the pressure means is provided, and the temperature. Various configurations such as a configuration in which the adjusting means is provided and a configuration in which the bending due to the reaction force of the pressure is less likely to occur are the same as those of the nip rollers of the first embodiment.

  However, since the press rollers 34, 36, 38, 40 do not directly contact the resin material 14 after molding, the surface finish state of the press rollers 34, 36, 38, 40 is more than that of each nip roller of the first embodiment. It may be in an inferior state.

  Further, since the nip belt 32 moves at a constant speed, a configuration corresponding to the so-called draw control operation method in the first embodiment is unnecessary. In addition, as long as the nip belt 32 can move at a constant speed, the drive means may not be provided for all the press rollers 34, 36, 38, 40 and the guide rollers 42, 44.

  The guide rollers 42 and 44 are provided with a function (driving means) that enables the nip belt 32 to be conveyed at a constant speed, and a predetermined tension (tension) is applied to the nip belt 32, so that the nip belt 32 and the press rollers 34, 36, A function (tension adjusting means) for preventing slippage with 38 and 40 is required.

  The tension adjusting unit may have the same configuration as the pressing unit provided in each nip roller of the first embodiment. The tension adjusting means may be provided on either of the guide rollers 42 and 44.

  In the resin sheet production line 10 ′ of FIG. 4, cooling devices 45, 46, 47, and 48 are provided as in the first embodiment, and the temperature adjustment function of the nip belt 32 is exhibited. The configuration of the cooling devices 45, 46, 47, and 48 may be the same as that of the cooling devices 26 and 28 of the first embodiment.

  Next, a method for producing a resin sheet using the resin sheet production line 10 ′ shown in FIG. 4 will be described.

  The sheet-like resin material 14 extruded from the die 12 is pressed between the mold roller 16 and the nip belt 32 disposed opposite to the mold roller 16 to transfer the uneven shape on the surface of the mold roller 16 to the resin material 14. The resin material 14 is peeled off from the mold roller 16 at the position of the press roller 40.

  The resin material 14 peeled off from the mold roller 16 is transported in the horizontal direction, gradually cooled by passing through the slow cooling zone 30, and cut into a predetermined length in the downstream product removing portion in a state where distortion is removed. And accommodate as a resin sheet product.

  In the production of this resin sheet, the extrusion speed of the resin material 14 from the die 12 can be 0.1 to 50 m / min, preferably 0.3 to 30 m / min. Accordingly, the peripheral speeds of the mold roller 16 and the nip belt 32 are also made to substantially match this.

  The pressing pressure of each press roller (the first press roller 34, the second press roller 36, the third press roller 38, and the fourth press roller 40) to the mold roller 16 is converted into a linear pressure (surface due to elastic deformation of each nip roller). It is preferably 0 to 200 kN / m (0 to 200 kgf / cm), more preferably 0 to 100 kN / m (0 to 100 kgf / cm) in terms of contact as a linear contact. .

  The tension of the nip belt 32 by the tension adjusting means (guide roller 42 or 44) is preferably 0.1 to 100 kN / m (0.1 to 100 kgf / cm).

  According to the manufacturing method of the resin sheet which concerns on this invention demonstrated above, even if it is a resin sheet with a large thickness distribution of the width direction at the time of shaping | molding, a desired cross-sectional shape can be obtained.

  As mentioned above, although embodiment of the manufacturing method of the resin sheet which concerns on this invention was described, this invention is not limited to the said embodiment, Various aspects can be taken.

  For example, the number and arrangement of nip rollers or press rollers can take various forms other than the present embodiment as long as the same function can be obtained.

  In addition, the temperature adjusting means, the cooling device (26 and the like), the slow cooling zone 30 and the like can adopt various aspects other than the present embodiment as long as the same function can be obtained.

The block diagram which shows the example of the production line of the resin sheet to which this invention is applied The perspective view of the state which cut off the end face of the resin material after molding on a straight line The perspective view of the state which cut off the end face of the resin material after molding on a straight line The block diagram which shows the other example of the production line of the resin sheet to which this invention is applied Configuration diagram showing production line of resin sheet of conventional example

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Resin sheet production line, 12 ... Die, 14 ... Resin material, 16 ... Mold roller, 18 ... 1st nip roller, 20 ... 2nd nip roller, 22 ... 3rd nip roller, 24 ... Release roller, 26, 28 ... Cooling Equipment, 30 ... Slow cooling zone

Claims (4)

The sheet-shaped resin material extruded from the die is clamped by a mold roller and a plurality of nip rollers arranged to face the mold roller,
The uneven shape on the surface of the mold roller is transferred to the resin material,
A method for producing a resin sheet, wherein the resin material after transfer is peeled off from the mold roller by being wound around a peeling roller disposed opposite to the mold roller.   The resin sheet according to claim 1, wherein the thickness difference between the thickest portion and the thinnest portion in the width direction of the resin material is 1 mm or more due to the uneven shape transferred to the resin material. Manufacturing method.   The method for producing a resin sheet according to claim 1 or 2, wherein the thinnest portion of the resin material has a thickness of 5 mm or less. Supplying a belt-shaped member between the mold roller and the plurality of nip rollers and / or the peeling roller;
The method for producing a resin sheet according to any one of claims 1 to 3, wherein the resin material is sandwiched between the belt-shaped member and the mold roller.

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