JP2006256055A - Manufacturing method of resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a resin sheet capable of obtaining a desired cross-sectional shape when the resin sheet large in the thickness distribution in its width direction at the time of molding is manufactured and especially suitable for use in the light guide plate arranged to the back of a display device of every kind or an optical element of every kind. <P>SOLUTION: The resin material 14 extruded from a die 12 is held under pressure between a mold roller 16 and nip rollers 18, 20 and 22 to transfer the surface uneven shape of the mold roller 16 and the resin material 14 having the surface uneven shape of the mold roller 16 transferred thereto is wound around a peel roller 24 to be peeled from the mold roller 16. The resin material 14 after peeling is brought into contact with a temperature conditioning roller 34 to uniformize the temperature distribution in the width direction of the resin material 14. <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 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. And 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 brought into contact with one or more roller members to Provided is a method for producing a resin sheet, characterized in that the temperature distribution in the width direction of the resin material is made uniform.

  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, peeled off from the mold roller, and the peeled resin material is brought into contact with one or more roller members. Thus, the temperature distribution in the width direction of the resin material is made uniform.

  In this way, even if the resin sheet has a large thickness distribution in the width direction during molding by contacting the resin material with one or more roller members to make the temperature distribution in the width direction uniform, The generated back surface irregularities are unlikely to occur, and the desired cross-sectional shape can be obtained by suppressing the deformation on the downstream side by early cooling and fixing immediately after molding.

  In the present invention, the set temperature of the roller member corresponding to the thick portion in the width direction of the resin material is controlled to be lower than the average temperature of the roller member, and corresponds to the thin portion in the width direction of the resin material. It is preferable to control the set temperature of the roller member portion to be higher than the average temperature of the roller member.

  In this way, by controlling the set temperature of the roller member corresponding to the thick part of the resin material to be low and controlling the set temperature of the roller member corresponding to the thin part to be high in the width direction during molding. Even with a resin sheet having a large thickness distribution, a desired cross-sectional shape can be obtained.

  Moreover, in this invention, it is preferable that the cross-sectional shape of the said roller member surface is the reverse shape of the uneven | corrugated shape transcribe | transferred to the said resin material. Thus, if the cross-sectional shape of the roller member surface is an inverted shape of the uneven shape of the resin material, the controllability of the temperature of the resin material is good, and the resin sheet has a large thickness distribution in the width direction during molding. However, 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. The resin material is peeled off from the mold roller by being wound around a peeling roller disposed to face the mold roller, and the thick portion in the width direction of the resin material after peeling is averaged by the local cooling means. Provided is a method for producing a resin sheet, which is controlled so as to be lower than a temperature, and a thin portion in the width direction of the resin material is controlled to be higher than an average temperature of the resin material by a local heat retaining means. To do.

  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, peeled off from the mold roller, and the thick portion of the resin material after peeling is averaged over the resin material The temperature is controlled to be lower than the temperature, and the thin portion is controlled to be higher than the average temperature of the resin material.

  In this way, even if the resin sheet has a large thickness distribution in the width direction at the time of molding, the local cooling means and the local heat retaining means make the temperature distribution in the width direction of the resin material uniform. The generated back surface irregularities are unlikely to occur, and the desired cross-sectional shape can be obtained by suppressing the deformation on the downstream side by early cooling and fixing immediately after molding.

  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 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. The temperature control roller 32 and the slow cooling zone 30 are configured.

  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, 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.

  The temperature adjustment roller 32 is a first means for making the temperature distribution in the width direction of the resin material 14 uniform, and the temperature adjustment roller 32 sets the set temperature of the portion corresponding to the thick portion in the width direction of the resin material 14. It is possible to control the temperature of the resin material 14 to be lower than the average temperature of the temperature control roller 32 and to control the set temperature of the portion corresponding to the thin portion of the resin material 14 in the width direction.

  FIG. 4 is a partial enlarged cross-sectional view showing the relationship between the temperature control roller 32 and the resin material 14. As described above, the cross-sectional shape of the resin material 14 is the same as that in FIG. 2, and the thick portions 14D, 14D,... Surrounded by a circle, and the thin portions 14E, 14E,. have.

  The cross-sectional shape of the temperature control roller 32 is an inverted shape of the concavo-convex shape transferred to the resin material 14. Thus, since the cross-sectional shape of the surface of the temperature control roller 32 is an inverted shape of the uneven shape of the resin material 14, the heat conduction by contact is good, and the temperature controllability of the resin material 14 is good. Therefore, even if it is the resin sheet 14 with the large thickness distribution of the width direction at the time of shaping | molding, a desired cross-sectional shape can be obtained.

  As described above, the temperature control roller 32 has the set temperature of the portions 32A, 32A,... Corresponding to the thick portions 14D, 14D,... In the width direction of the resin material 14 lower than the average temperature of the temperature control roller 32. It is possible to control, and the set temperature of the portions 32B, 32B... Corresponding to the thin portions 14E, 14E... In the width direction of the resin material 14 can be controlled to be higher than the average temperature of the temperature control roller 32.

  As a specific configuration for adopting such a control method, the cooling water flow path provided in the circumferential direction of the portions 32A, 32A... And the heat medium flow provided in the circumferential direction of the portions 32B, 32B. The structure which forms a channel | path, circulates cooling water to these cooling water flow paths, and circulates a heat medium to these heat medium flow paths is employable. The supply of the cooling water to the cooling water flow path and the supply of the heat medium to the heat medium flow path can be realized by providing a rotary joint at the end of the temperature control roller 32 and supplying it via this.

  Moreover, as another specific structure for employ | adopting said control method, part 32A, 32A ... is cooled with the cold wind nozzle provided in the back side (part on the opposite side of the resin material 14) of part 32A, 32A ... A configuration in which the portions 32B, 32B,... Are heated by a hot air nozzle provided on the back side of the portions 32B, 32B,.

  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. Point, the surface of a plurality of points in the width direction of the resin material 14 wound around the mold roller 16 and the peeling roller 24 (on the opposite side of the roller), the portions 32A, 32A of the temperature control roller 32, and the portions 32B, 32B,. .., A plurality of thick portions 14D, 14D... In the width direction of the resin material 14 immediately after the temperature control roller 32, and a plurality of thin portions 14E, 14E.

  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 conveyed in the horizontal direction and brought into contact with the temperature control roller 32, so that the temperature distribution in the width direction of the resin material 14 is made uniform. Accordingly, the thick portion 14D in the width direction of the resin material 14 is controlled to be lower than the average temperature of the resin material 14 by the portion 32A of the temperature control roller 32, and the thin portion 14E in the width direction of the resin material 14 is heated. The temperature is controlled to be higher than the average temperature of the resin material 14 by the portion 32B of the adjusting roller 32.

  In the downstream of the temperature control roller 32, the resin material 14 is gradually cooled by passing it through the slow cooling zone 30, and in a state in which the distortion is removed, the resin material 14 is cut into a predetermined length at the downstream product removing portion, and the product of the resin sheet As housed.

  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. 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.

  In the present embodiment, one nip roller 18 is used instead of the three nip rollers (the first nip roller 18, the second nip roller 20, and the third nip roller 22) of the first embodiment. Further, instead of the temperature control roller 32 of the first embodiment (first means for making the temperature distribution in the width direction of the resin material 14 uniform), the temperature distribution in the width direction of the resin material 14 is made uniform. Two means 34 are used.

  FIG. 6 is a 6-6 line arrow view showing the positional relationship between the second means 34 and the resin material 14. As shown in FIG. 6, the second means 34 includes a plurality of coolers 36, 36... That are local cooling means and a plurality of heaters 38, 38.

  The cooler 36 is disposed so as to face the lower surface of the thick portion 14D of the resin material 14, and the heater 38 is disposed so as to face the lower surface of the thin portion 14E of the resin material 14. With this configuration of the second means 34, the thick portion 14 </ b> D in the width direction of the resin material 14 can be controlled to be lower than the average temperature of the resin material 14 by the cooler 36. The portion 14E can be controlled by the heater 38 so as to be higher than the average temperature of the resin material 14.

  As the cooler 36, a known cooling means such as a water cooling jacket or a refrigerator can be adopted. As the heater 38, a known heat retaining means (heating means) such as a sheath heater or a dryer (hot air blowing means) can be adopted.

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

  The resin material 14 peeled off from the mold roller 16 is conveyed in the horizontal direction and passed over the second means 34. Thus, the thick portion 14D in the width direction of the resin material 14 is controlled by the cooler 36 so as to be lower than the average temperature of the resin material 14, and the thin portion 14E in the width direction of the resin material 14 is controlled by the heater 38. It is controlled to be higher than the average temperature.

  Downstream of the second means 34, the resin material 14 is gradually cooled by passing it through the slow cooling zone 30, and in a state in which distortion is removed, the resin material 14 is cut into a predetermined length at the downstream product removing portion, and the resin sheet 14 House as a product.

  According to the resin sheet manufacturing method according to the present invention described above (first and second embodiments), a desired cross-sectional shape is obtained even with a resin sheet having a large thickness distribution in the width direction during molding. be able to.

  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 temperature control rollers 34 as the first means for uniformizing the temperature distribution in the width direction of the resin material 14 may be various aspects other than the present embodiment as long as the same function can be obtained. Can be taken.

  Further, the second means for making the temperature distribution in the width direction of the resin material 14 uniform, the slow cooling zone 30 and the like can take various aspects other than the present embodiment as long as the same function can be obtained. obtain.

  Also, 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.

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 Partial enlarged sectional view showing the relationship between the temperature control roller and the resin material The block diagram which shows the other example of the production line of the resin sheet to which this invention is applied 6-6 line arrow figure which shows the positional relationship of a 2nd means and resin material 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, 30 ... Slow cooling zone 32 ... Temperature control roller, 34 ... Second means, 36 ... Cooler, 38 ... Heater

Claims (6)

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,
A method for producing a resin sheet, wherein the resin material after peeling is brought into contact with one or more roller members to achieve uniform temperature distribution in the width direction of the resin material.   The set temperature of the portion of the roller member corresponding to the thick portion in the width direction of the resin material is controlled to be lower than the average temperature of the roller member, and the roller member corresponding to the thin portion in the width direction of the resin material is controlled. The method for producing a resin sheet according to claim 1, wherein the set temperature of the portion is controlled to be higher than the average temperature of the roller member.   The method for producing a resin sheet according to claim 1, wherein a cross-sectional shape of the surface of the roller member is an inverted shape of the concavo-convex shape transferred to the resin material. 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 thick portion in the width direction of the resin material after peeling is controlled to be lower than the average temperature of the resin material by a local cooling means, and the thin portion in the width direction of the resin material is controlled by the local heat retaining means. A method for producing a resin sheet, wherein the temperature is controlled to be higher than the average temperature.   5. 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. 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 1-5 characterized by the above-mentioned.

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