JP2006056216A - 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 roller 18 arranged in opposed relation to the mold roller and the uneven shape on the surface of the mold roller is transferred to the resin material. 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 and held under pressure by a transfer template 26 moving at a speed almost same to the traveling speed of the resin material and a back plate 28 arranged in opposed relation to the transfer template to move at the same speed to transfer the uneven shape on the surface of the transfer template to the resin material. <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 (retraction due to shrinkage when the resin is cured), overall surface shape transfer rate is reduced, and sharp edge shapes 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 between a mold roller and a nip roller disposed so as to face the mold roller, and forms the uneven shape on the surface of the mold roller. The resin material after transfer is peeled off from the mold roller by winding it on a peeling roller disposed opposite to the mold roller, and the resin material after peeling is approximately the same as the traveling speed of the resin material. And a back plate which is arranged opposite to the transfer mold plate and moves at the same speed, and transfers the uneven shape on the surface of the transfer mold plate to the resin material. A manufacturing method is provided.

  According to the present invention, a sheet-shaped resin material is sandwiched between a mold roller and a nip roller, the uneven shape is transferred to the resin material, the resin material is wound around the peeling roller, and then peeled off from the mold roller, and then the resin material is removed. The transfer mold plate moving at substantially the same speed and the back plate are clamped to transfer the uneven shape on the transfer mold plate surface to the resin material. In this way, by using a mold roller and a transfer mold plate, even a resin sheet having a large thickness distribution in the width direction during molding can be gradually brought closer to the design shape, and a desired cross-sectional shape can be obtained. Obtainable.

  In the present invention, a sheet-like resin material extruded from a die is sandwiched between a first mirror roller and a second mirror roller disposed opposite to the first mirror roller, and the resin material is pressed to a predetermined thickness. Then, the molded resin material is peeled off from the first mirror roller by wrapping the molded resin material on a peeling roller disposed opposite to the first mirror roller, and the resin material after peeling is removed from the resin material. The transfer mold plate that moves at substantially the same speed as the traveling speed of the transfer plate and the back plate that is disposed opposite to the transfer mold plate and moves at the same speed are used to transfer the uneven shape on the surface of the transfer mold plate to the resin material. The manufacturing method of the resin sheet characterized by this is provided.

  According to the present invention, a sheet-shaped resin material is pressed between the first mirror roller and the second mirror roller to form a predetermined thickness, and the resin material is wound around the peeling roller to be peeled off from the mold roller. Then, the resin material is sandwiched between the transfer mold plate and the back plate that move at substantially the same speed to transfer the uneven shape on the surface of the transfer mold plate to the resin material. In this way, by using a transfer mold plate or the like, even a resin sheet having a large thickness distribution in the width direction during molding can be gradually brought closer to the design shape, and a desired cross-sectional shape can be obtained. it can.

  In the present invention, a plurality of sets of the transfer mold plate and the back plate are provided, the resin material is sandwiched between the transfer mold plate and the back plate from a predetermined position downstream of the peeling roller, and the resin is moved after a predetermined distance. It is preferable to release the pinching force of the material. In this way, multiple sets of transfer mold plates and back plates are provided, and the resin material is sandwiched and conveyed for a predetermined distance, so that even a resin sheet with a large thickness distribution during molding is gradually designed The shape can be approximated, and a desired cross-sectional shape can be obtained.

  In the present invention, the sheet-shaped resin material extruded from the die is sandwiched between a mold roller and a nip roller disposed opposite to the mold roller, and the uneven shape on the surface of the mold roller is transferred to the resin material. A transfer mold plate that is peeled off from the mold roller by winding the resin material on a peeling roller disposed opposite to the mold roller, and the peeled resin material is moved at a speed substantially equal to the traveling speed of the resin material. And a flat bed disposed opposite to the transfer mold plate to transfer the uneven shape on the surface of the transfer mold plate to the resin material.

  According to the present invention, a sheet-shaped resin material is sandwiched between a mold roller and a nip roller, the uneven shape is transferred to the resin material, the resin material is wound around the peeling roller, and then peeled off from the mold roller, and then the resin material is removed. The imprint shape on the surface of the transfer mold plate is transferred to the resin material by pressing between the transfer mold plate and the flat bed moving at substantially the same speed. In this way, by using a mold roller and a transfer mold plate, even a resin sheet having a large thickness distribution in the width direction during molding can be gradually brought closer to the design shape, and a desired cross-sectional shape can be obtained. Obtainable.

  In the present invention, a sheet-like resin material extruded from a die is sandwiched between a first mirror roller and a second mirror roller disposed opposite to the first mirror roller, and the resin material is pressed to a predetermined thickness. Then, the molded resin material is peeled off from the first mirror roller by wrapping the molded resin material on a peeling roller disposed opposite to the first mirror roller, and the resin material after peeling is removed from the resin material. A transfer mold plate that moves at substantially the same speed as the traveling speed of the sheet and a flat bed that is disposed opposite to the transfer mold plate, and transfers the uneven shape on the surface of the transfer mold plate to the resin material. A method for producing a resin sheet is provided.

  According to the present invention, a sheet-shaped resin material is pressed between the first mirror roller and the second mirror roller to form a predetermined thickness, and the resin material is wound around the peeling roller to be peeled off from the mold roller. Then, the resin material is sandwiched between the transfer mold plate that moves at substantially the same speed and the flat bed to transfer the uneven shape on the surface of the transfer mold plate to the resin material. In this way, by using a transfer mold plate or the like, even a resin sheet having a large thickness distribution in the width direction during molding can be gradually brought closer to the design shape, and a desired cross-sectional shape can be obtained. it can.

  In the present invention, it is preferable that a belt-like member that moves at substantially the same speed as the traveling speed of the resin material is disposed between the resin material and the flat bed. Thus, by employing the belt-like member, friction between the flat bed surface and the resin material back surface can be eliminated, and the resin material back surface can be maintained in a good state.

  Further, in the present invention, a plurality of the transfer mold plates are provided, the resin material is clamped between the transfer mold plate and the flat bed from a predetermined position downstream of the peeling roller, and the resin material is clamped after traveling a predetermined distance. Is preferably released. In this way, by providing a plurality of transfer mold plates and transporting them for a predetermined distance while sandwiching the resin material, even a resin sheet with a large thickness distribution in the width direction during molding gradually approaches the design shape. And a desired cross-sectional shape can be obtained.

  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.

  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 nip roller 18 disposed opposite to the mold roller 16, a peeling roller 24 disposed opposite to the mold roller 16, a plurality of transfer mold plates 26, 26... Disposed downstream of the peeling roller 24, and a transfer mold plate 26. Are configured to be opposed to each other.

  The slit size of the die 12 is formed such 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 by the mold roller 16 and the nip roller 18. It is arranged to be pushed between.

  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 18 is a roller that is disposed to face the mold roller 16 and clamps the resin material 14 with the mold roller 16.

  The surface of the nip roller 18 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 roller 18 is preferably 0.5 μm or less in Ra, and more preferably 0.2 μm or less.

  The material of the nip roller 18 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, etc. These materials, ceramics, and various composite materials can be used.

  The nip roller 18 is rotationally driven in a direction indicated by an arrow in FIG. 1 at a predetermined peripheral speed by a driving means (not shown). In addition, although the structure which does not provide a drive means in the nip roller 18 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 nip roller 18 is provided with a pressing means (not shown) so that the resin material 14 between the nip roller 18 and the mold roller 16 can be pressed with a predetermined pressure. The pressurizing means is configured to apply pressure in the normal direction at the contact point between the nip roller 18 and the mold roller 16, and various known means such as a motor driving means, an air cylinder, and a hydraulic cylinder can be employed.

  The nip roller 18 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 roller 18 (opposite side of the mold roller 16), a configuration in which a crown shape (middle and high shape) is adopted, and a rigidity in the central portion in the axial direction of the roller is large. A configuration of a roller having such an intensity distribution, a configuration combining these, and the like can be employed.

  The nip roller 18 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 the temperature of the nip roller 18 to an optimal state.

  That is, if the set temperature of the nip roller 18 is too low, the resin material 14 in a molten state is rapidly cooled, and distortion is generated in the resin material 14, which is not preferable. If the set temperature of the nip roller 18 is too high, Since the resin material 14 is peeled off from the mold roller 16 and the surface of the resin material 14 becomes a free surface state, the uneven pattern shape collapses, which is not preferable.

  Further, even when the set temperature of the nip roller 18 is excessively lowered, the viscosity of the resin material 14 increases, and it is not preferable that the nip roller 18 cannot be wound around the peeling roller 24.

  The roller set temperature of the nip roller 18 includes 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 outer diameter of the mold roller 16, The optimum value should be selected according to the uneven pattern shape.

  As the roller temperature adjusting means of the nip roller 18, 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.

  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, it is possible to employ a configuration in which a cooling device is provided to assist the temperature adjusting means of the nip roller 18 and the peeling roller 24.

  As such a cooling device, for example, an air nozzle can be employed. In this case, two sets of air nozzles are provided, one air nozzle blows air to the resin material 14 being conveyed, and the other one air nozzle blows air to the peeling roller 24 to directly control the temperature of the resin material 14. The temperature of the resin material 14 can be controlled via the peeling roller 24.

  At that time, the air temperature and the air supply amount (spraying flow rate) are as follows: 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 conveyance speed of the resin material 14, The optimum value should be selected according to the outer diameter, the uneven pattern shape of the mold roller 16, the set temperature of the nip roller 18, and the like.

  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, 180 degrees downstream of the nip roller 18 with the mold roller 16 interposed therebetween. Has been placed.

  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.

  A regular uneven shape is formed on the surface (lower surface in FIG. 1) of the transfer mold plate 26. This regular uneven | corrugated shape can be made into the reverse shape of the resin material 14 after the shaping | molding shown by above-mentioned FIG.

  The materials used for the surface of the transfer mold plate 26 include various steel members, stainless steel, copper, zinc, brass, rubber-lined surfaces of these metal materials, HCr plating, Cu plating, Ni Those plated, such as plating, ceramics, and various composite materials can be used.

  As a method for forming the concavo-convex pattern on the surface of the transfer mold plate 26, although it depends on the concavo-convex pattern (pitch, depth, etc.) and the material of the surface of the transfer mold plate 26, in general, an NC machine tool (a machining center is representative). The combination of the cutting process and finish 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 transfer mold plate 26 is preferably 0.5 μm or less, more preferably 0.2 μm or less, in terms of Ra.

  The transfer mold plate 26 is provided with temperature adjusting means. By providing such a temperature adjusting means, it is possible to control the temperature of the transfer mold plate 26 due to the resin material 14 in a high temperature state so as to suppress the temperature rise or the rapid temperature drop. As such a temperature control means, a configuration in which the temperature-controlled oil is circulated inside the transfer mold plate 26 can be preferably employed.

  The back plate 28 is a plate-like member that is conveyed so as to face the transfer mold plate 26 and clamps the resin material 14 with the transfer mold plate 26.

  The surface of the back plate 28 (upper surface in FIG. 1) 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 back plate 28 surface is preferably 0.5 μm or less in terms of Ra, and more preferably 0.2 μm or less.

  It is also possible to pattern the back surface of the back plate 28 and form a pattern on the front and back surfaces of the resin material 14. Examples of such a concave-convex pattern shape on the back surface include a fine pattern disclosed in JP-A-7-314567, a prism shape (10 to 200 μm pitch, apex angle 45 to 100 °), a lenticular lens, a Fresnel lens, Examples include embossing (light diffusion pattern).

  As the material of the back plate 28, various steel members, stainless steel, copper, zinc, brass, rubber-lined surfaces of these metal materials, and plating such as HCr plating, Cu plating, and Ni plating on these metal materials. Applied materials, ceramics, and various composite materials can be used.

  The back plate 28 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 the temperature of the back board 28 to an optimal state.

  That is, if the set temperature of the back plate 28 is too low, the resin material 14 is rapidly cooled, and distortion is generated in the resin material 14. This is not preferable, and if the set temperature of the back plate 28 is too high, the resin material 14 is peeled off from the transfer mold plate 26 and the surface of the resin material 14 is in a free surface state.

  The set temperature of the back plate 28 includes 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 conveyance speed of the resin material 14, and the uneven pattern of the mold roller 16 and the transfer mold plate 26. The optimum value should be selected depending on the shape and the like.

  As the temperature adjusting means of the back plate 28, a configuration in which the temperature-controlled oil is circulated inside the back plate 28 can be preferably employed.

  As other temperature adjusting means, various known means such as a structure in which a sheath heater is embedded in the back plate 28 and a structure in which a dielectric heating means is disposed in the vicinity of the back plate 28 can be adopted.

  The transfer mold plate 26 and the back plate 28 are conveyed in a direction indicated by an arrow in FIG. 1 at a predetermined speed by a driving unit (not shown). That is, a plurality of sets of transfer mold plates 26 and back plates 28 are provided. As shown in FIG. 1, the transfer mold plate 26 and the back plate 28 are made of resin from a predetermined position A downstream of the peeling roller 24. The material 14 is nipped and conveyed so as to release the nipping pressure of the resin material 14 at a predetermined position B after traveling a predetermined distance.

  As this drive means, a chain member that is wound around and driven by a sprocket supports both side surfaces of the transfer mold plate 26 and the back plate 28 (corresponding to the front side and the back side of the paper in FIG. 1). Various known configurations such as a configuration employing various link mechanisms can be employed. By this driving means, the transfer mold plate 26 and the back plate 28 are circulated and conveyed.

  The transfer mold plate 26 and the back plate 28 are provided with pressurizing means (not shown) so that the resin material 14 between the transfer mold plate 26 and the back plate 28 can be clamped with a predetermined pressure. . The pressurizing means is provided on the back surfaces of the transfer mold plate 26 and the back plate 28 (the upper surface of the transfer mold plate 26 and the lower surface of the back plate 28). A guide member that restricts movement in the back direction can be employed.

  A configuration in which such a guide member is provided, and either the transfer mold plate 26 or the back plate 28 is configured by two upper and lower members, and an air pressurizing unit is provided between the two upper and lower members is also preferable. Can be adopted.

  It is preferable to provide surface temperature measuring means (not shown) so that the surface temperatures of the respective rollers, transfer mold plate 26, and 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.

  Further, the monitoring result of such surface temperature measuring means can be fed back to the temperature adjusting means of each roller, transfer mold plate 26, 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. Further, the detection result by such a detecting means can be compared with a set value and fed back to the driving means for each roller or transfer mold plate 26.

  Furthermore, a slow cooling zone (or annealing zone) can also be provided downstream of the resin sheet production line 10 of FIG. Such a slow cooling zone is provided in order to prevent a rapid temperature change of the resin material 14 downstream of the resin sheet production line 10. When a sudden temperature change occurs in the resin material 14, for example, the inside of the resin material 14 is in a plastic state while the vicinity of the surface of the resin material 14 is in an elastic 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 (or annealing zone), 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 can be adopted. 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.

  A cleaning device (cleaning zone), a defect inspection device (inspection zone), a laminating device, a side cutter, a cross cutter, and an accumulating unit are provided in the downstream of the resin sheet production line 10 in FIG. 1 (downstream of the slow cooling zone). It is done.

  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 pressed between the mold roller 16 and the nip roller 18 disposed opposite to the mold roller 16, and the uneven shape on the surface of the mold roller 16 is transferred to the resin material 14. Is peeled off from the mold roller 16 by being wound around a peeling roller 24 disposed opposite to the mold roller 16.

  The transfer material plate 26 and the back plate 28 that transport the resin material 14 peeled from the mold roller 16 in the horizontal direction and move at a speed substantially equal to the traveling speed of the resin material 14 from a predetermined position A downstream of the peeling roller 24. Then, the concavo-convex shape on the surface of the transfer mold plate 26 is transferred to the resin material 14, and after traveling a predetermined distance, the clamping pressure of the resin material 14 is released at a predetermined position B. That is, in the configuration of FIG. 1, the concave and convex shape is transferred to the resin material 14 by four sets of the transfer mold plate 26 and the back plate 28.

  If necessary, it is gradually cooled by passing through a slow cooling zone (or annealing zone) (not shown), and after being distorted, it is cut into a predetermined length at the downstream product take-off section to obtain a resin sheet product. Accommodate.

  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 subsequent driving of the peeling roller 24 and the transfer mold plate 26 (also the back plate 28) is a so-called draw control in which the peeling roller 24 and the transfer mold plate 26 are gradually increased from the peripheral speed of the mold roller 16 in this order. The driving method. The draw value between the peeling roller 24 and the transfer mold plate 26 is preferably 0 to 3%, and more preferably 0 to 1%.

  However, the driving speed of each transfer mold plate 26 (also the back plate 28) needs to be constant. That is, as shown in FIG. 1, the transfer mold plate 26 and the back plate 28 that are sandwiching the resin material 14 are transported adjacent to each other with no gap therebetween. If this is adopted, a gap is generated between them, and a seam shape is generated in the resin material 14 at that portion, which is not preferable.

  If the length of the transfer mold plate 26 and the back plate 28 in the conveying direction is made substantially equal to the product length of the resin material 14, there is no problem even if such a seam shape is generated. An operation method of draw control can also be adopted.

  Note that it is preferable to control the speed unevenness of each roller and the transfer mold plate 26 (also the back plate 28) to be within 1% of the set value.

  The pressing pressure of the nip roller 18 against the mold roller 16 is 0 to 200 kN / m (0 to 200 kgf / cm) in terms of linear pressure (value converted assuming that the surface contact due to elastic deformation of each nip roller is linear contact). It is preferable to set it to 0 to 100 kN / m (0 to 100 kgf / cm).

The clamping pressure of the resin material 14 between the transfer mold plate 26 and the back plate 28 is preferably 0 to ²⁰ MPa (0 to 200 kgf / cm ² ) in terms of surface pressure, and preferably 2.5 to 10 MPa (25 to 100 kgf / cm ^2). ) Is more preferable.

  Further, the clamping pressure of the resin material 14 by the transfer mold plate 26 and the back plate 28 can be changed during the movement from the point A to the point B. For example, it is possible to control to gradually increase the clamping pressure as the point B is moved from the point A.

  Further, the clearance between the transfer mold plate 26 and the back plate 28 is controlled without controlling the clamping force of the resin material 14 between the transfer mold plate 26 and the back plate 28 by the pressurizing means (air pressurizing means or the like) described above. It can also be controlled by changing.

  The temperature control of the mold roller 16, the nip roller 18, the peeling roller 24, the transfer mold plate 26, and the back plate 28 is performed in the order of the nip roller 18, the peeling roller 24, and from the transfer mold plate 26 and the back plate 28 at point A. It is preferable to set for each member so that the temperature can be lowered in the order of the transfer mold plate 26 and the back plate 28 at the point B.

  The resin material 14 at the point A is preferably at a temperature equal to or higher than the softening point Ta of the resin, and the resin material 14 at the point B is preferably equal to or lower than the softening point Ta of the resin. At this time, when a polymethylmethacrylate resin is employed as the resin material 14, the set temperature of the transfer mold plate 26 and the back plate 28 at the point A can be 110 to 250 ° C., and the transfer mold plate 26 and the back plate at the point B The set temperature of 28 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 surfaces of the mold roller 16 and the transfer mold plate 26 does not need to be the inverted shape of the surface of the resin material 14 in FIG. 2 or 3, and the resin material 14 is considered in consideration of the shrinkage allowance of the resin material 14. A shape offset from this shape may be used so that the product shape of FIG.

  Furthermore, the structure which makes the uneven | corrugated shape transcribe | transferred to the resin material 14 approach a design shape in steps can also be employ | adopted preferably. For example, even if the endless groove having the inverted cross section shown in FIG. 2 is formed on the mold roller 16, it is often difficult for the resin material 14 to follow this shape. As long as it is possible, the cross-sectional shape of the mold roller 16 may be a shape that approximates the design shape, and may be configured to gradually approach the design shape.

  FIG. 4 is a cross-sectional view of the resin material 14 at each stage of molding. Among these, (a) is a cross section of the resin material 14 immediately after the die 12, and (c) is a cross section of the design shape of the product. This intermediate (b) is a cross section of the process in which the resin material 14 approaches the design shape step by step.

  Therefore, an endless groove having an inverted shape as shown in (b) may be formed in the mold roller 16 as well. In addition, the imaginary line (two-dot chain line) in (a) and (b) shows the cross section of the design shape of a product.

  Next, another embodiment (second embodiment) of the method for producing a resin sheet according to the present invention will be described in detail. FIG. 5 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.

  This embodiment is different from the first embodiment only in that a mirror roller 17 is used in place of the mold roller 16 of the first embodiment.

  That is, in the resin sheet production line 10 ′, the surface of the mirror roller 17 is formed in the same finished state as the nip roller 18, and other configurations are the same as those of the mold roller 16 of the first embodiment. Is formed.

  Next, a method for producing a resin sheet using the resin sheet production line 10 ′ shown in FIG. 5 will be described.

  The sheet-like resin material 14 extruded from the die 12 is pressed between a mirror roller 17 and a nip roller 18 disposed opposite to the mirror roller 17 to form the resin material 14 into a plate having a predetermined thickness. Is peeled off from the mirror roller 17 by being wound around a peeling roller 24 disposed opposite to the mirror roller 17.

  The resin material 14 peeled off from the mirror roller 17 is conveyed in the horizontal direction, and is transferred from a predetermined position A downstream of the peeling roller 24 at a speed substantially equal to the traveling speed of the resin material 14 and the back plate 28. Then, the resin material 14 is clamped to transfer the uneven shape on the surface of the transfer mold 26 to the resin material 14, and the clamp of the resin material 14 is released at a predetermined position B after traveling a predetermined distance.

  If necessary, it is gradually cooled by passing through a slow cooling zone (or annealing zone) (not shown), and after being distorted, it is cut into a predetermined length at the downstream product take-off section to obtain a resin sheet product. Accommodate.

  In the production of this resin sheet, the extrusion speed of the resin material 14 from the die 12, the peripheral speed of the mirror roller 17 and the nip roller 18, the pressing pressure by the nip roller 18 and the transfer mold plate 26, and the setting of each roller and transfer mold plate 26 etc. Each condition such as temperature can be substantially the same as in the first embodiment.

  Also according to the present embodiment, the resin material 14 can be molded in substantially the same manner as in the first embodiment. However, when the resin material 14 having the same cross-sectional shape as that of the first embodiment is obtained, the pressing pressure by the transfer mold plate 26 is increased or the distance from the predetermined position A to the point B is increased because there is no transfer by the mold roller 16. Extensions or minor changes are necessary.

  Next, still another embodiment (third embodiment) of the method for producing a resin sheet according to the present invention will be described in detail. FIG. 6 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.

  This embodiment is different from the first embodiment only in that a flat bed 30, a belt-like member 32, and guide rollers 34, 34 ... are used instead of the back plates 28, 28 ... of the first embodiment. It is.

  That is, in the resin sheet production line 10 ″, the resin material 14 is pressed between the transfer mold plates 26, 26... And the flat bed 30 disposed opposite to the transfer mold plates 26, 26. A configuration in which the uneven shape is transferred to the resin material 14 is employed.

  As described above, the flat bed 30 is employed instead of the back plates 28, 28... And has a simple configuration with few movable parts, and is easy to manufacture.

  Further, a belt-like member 32 that moves at approximately the same speed as the traveling speed of the resin material 14 is disposed between the resin material 14 and the flat bed 30. The belt-like member 32 is stretched around guide rollers 34, 34..., And is moved at substantially the same speed as the traveling speed of the resin material 14 by rotational driving of one or more guide rollers 34.

  Thus, the belt-shaped member 32 can eliminate friction between the surface of the flat bed 30 and the back surface of the resin material 14, and can maintain the back surface of the resin material 14 in a good state.

  The flat bed 30 is a platen-like member that is substantially the same width as the resin material 14 and has a flat surface, and has a structure that does not easily deform even when subjected to the pressing force of the transfer mold plates 26, 26. desirable. Such a flat bed 30 can be formed of various metal members, ceramics, or the like.

  The surface of the belt-like member 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 belt-like member 32 is preferably 0.5 μm or less in Ra, and more preferably 0.2 μm or less.

  As the material of the belt-like member 32, various steel members, stainless steel, those obtained by rubber lining these metal materials, those obtained by applying plating such as HCr plating, Cu plating, Ni plating, and the like, and Various composite materials can be used.

  The guide rollers 34, 34... Have a function (driving means) that enables the belt-like member 32 to be conveyed at a constant speed, and a predetermined tension (tension) is applied to the belt-like member 32. 14 (a tension adjusting means) is required.

  This tension adjusting means may be provided in any one of the guide rollers 34, 34.

  Next, a resin sheet manufacturing method using the resin sheet manufacturing line 10 ″ shown in FIG. 6 will be described.

  The sheet-shaped resin material 14 extruded from the die 12 is pressed between the mold roller 16 and the nip roller 18 disposed opposite to the mold roller 16, and the uneven shape on the surface of the mold roller 16 is transferred to the resin material 14. Is peeled off from the mold roller 16 by being wound around a peeling roller 24 disposed opposite to the mold roller 16.

  A transfer mold plate 26 that transports the resin material 14 peeled off from the mold roller 16 in the horizontal direction and moves at a speed substantially equal to the traveling speed of the resin material 14 from a predetermined position A downstream of the peeling roller 24, The resin material 14 is clamped by a belt-like member 32 that moves at approximately the same speed as the traveling speed of the resin material 14 on the surface of the sheet 30, the uneven shape on the surface of the transfer template 26 is transferred to the resin material 14, and travels a predetermined distance. Later, the pinching pressure of the resin material 14 is released at a predetermined position B.

  If necessary, it is gradually cooled by passing through a slow cooling zone (or annealing zone) (not shown), and after being distorted, it is cut into a predetermined length at the downstream product take-off section to obtain a resin sheet product. Accommodate.

  In the production of the resin sheet, the extrusion speed of the resin material 14 from the die 12, the peripheral speed of the mold roller 16 and the nip roller 18, the pressing pressure by the nip roller 18 and the transfer mold plate 26, the setting of each roller and the transfer mold plate 26, etc. Each condition such as temperature can be substantially the same as in the first embodiment.

  According to each 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 the transfer mold plates 26 may take various aspects other than the present embodiment as long as the same function can be obtained.

  In addition, regarding the temperature adjusting means, the pressurizing means, and the like, various aspects other than the present embodiment can be adopted 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 Cross-sectional view of resin material at each stage of molding The block diagram which shows the other example of the production line of the resin sheet to which this invention is applied The block diagram which shows the further another 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 ... Nip roller, 24 ... Release roller, 26 ... Transfer mold plate, 28 ... Back plate, 30 ... Flat bed, 32 ... Belt 34, guide roller

Claims (9)

The sheet-shaped resin material extruded from the die is pinched by a mold roller and a nip roller disposed opposite to the mold roller,
The uneven shape on the surface of the mold roller is transferred to the resin material,
The resin material after the transfer is peeled off from the mold roller by winding it around a peeling roller disposed opposite to the mold roller,
The resin material after peeling is sandwiched between a transfer mold plate that moves at substantially the same speed as the traveling speed of the resin material, and a back plate that is disposed opposite to the transfer mold plate and moves at the same speed,
A method for producing a resin sheet, wherein the uneven shape on the surface of the transfer template is transferred to the resin material. The sheet-like resin material extruded from the die is sandwiched between the first mirror roller and the second mirror roller disposed opposite to the first mirror roller,
Molding the resin material to a predetermined thickness,
The resin material after molding is peeled off from the first mirror roller by wrapping it on a peeling roller disposed opposite to the first mirror roller,
The resin material after peeling is sandwiched between a transfer mold plate that moves at substantially the same speed as the traveling speed of the resin material, and a back plate that is disposed opposite to the transfer mold plate and moves at the same speed,
A method for producing a resin sheet, wherein the uneven shape on the surface of the transfer template is transferred to the resin material. A plurality of sets of the transfer mold plate and the back plate are provided,
The resin material is clamped between the transfer mold plate and the back plate from a predetermined position on the downstream side of the peeling roller,
The method for producing a resin sheet according to claim 1 or 2, wherein the clamping pressure of the resin material is released after traveling for a predetermined distance. The sheet-shaped resin material extruded from the die is pinched by a mold roller and a nip roller disposed opposite to the mold roller,
The uneven shape on the surface of the mold roller is transferred to the resin material,
The resin material after the transfer is peeled off from the mold roller by winding it around a peeling roller disposed opposite to the mold roller,
The resin material after peeling is clamped between a transfer mold plate that moves at substantially the same speed as the traveling speed of the resin material, and a flat bed that is arranged opposite to the transfer mold plate,
A method for producing a resin sheet, wherein the uneven shape on the surface of the transfer template is transferred to the resin material. The sheet-like resin material extruded from the die is sandwiched between the first mirror roller and the second mirror roller disposed opposite to the first mirror roller,
Molding the resin material to a predetermined thickness,
The resin material after molding is peeled off from the first mirror roller by wrapping it on a peeling roller disposed opposite to the first mirror roller,
The resin material after peeling is clamped between a transfer mold plate that moves at substantially the same speed as the traveling speed of the resin material, and a flat bed that is arranged opposite to the transfer mold plate,
A method for producing a resin sheet, wherein the uneven shape on the surface of the transfer template is transferred to the resin material.   The method for producing a resin sheet according to claim 4 or 5, wherein a belt-like member that moves at substantially the same speed as the traveling speed of the resin material is disposed between the resin material and the flat bed. . Provide a plurality of the transfer template,
The resin material is clamped between the transfer mold plate and the flat bed from a predetermined position downstream of the peeling roller,
The method for producing a resin sheet according to any one of claims 4 to 6, wherein the clamping pressure of the resin material is released after traveling for a predetermined distance.   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. The manufacturing method of the resin sheet of 1 item | term. The thickness of the thinnest part of the said resin material is 5 mm or less, The manufacturing method of the resin sheet of any one of Claims 1-8 characterized by the above-mentioned.

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