JP2010069781A - Method for production of thickness-biased resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for production of a thickness-biased resin sheet excellent in appearance. <P>SOLUTION: The method for production of a thickness-biased resin sheet includes: an extrusion process 112 for extruding a molten resin from a die 12 in a sheet-like form; a sheet-molding process 114 for molding a resin sheet 14 by holding the extruded molten resin sheet 14a between a die roller 16 and a nip roller 18, transferring the surface processed form of the die roller 16 to the molten resin sheet 14a, and cooling and solidifying; a peeling process 115 for peeling the resin sheet 14 from a peeling roller 20; and a conveying process 117 for conveying the resin sheet 14 while drawing by a drawing roller 24. In such processes, when the maximum value of a clearance between the nip roller 18 and the die roller 16 is defined as a [mm], and that of the clearance between the die roller 16 and the peeling roller 20 as b [mm], a and b satisfy a≤b≤a+0.3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In general, in the extrusion molding of a resin sheet, the molten resin sheet extruded from the T-die is cooled by a cooling roller, and then cooled and solidified by air cooling in a conveying portion while being taken up by a take-up roller, and then in a width direction by a cutting machine. And is formed into a sheet shape.

  When the shape of the sheet to be molded is a flat plate, the number and arrangement of cooling rollers, size, temperature, clearance between the rollers, etc. are resin materials in order to form a sheet with excellent warp and uneven thickness and excellent appearance. It is adjusted as appropriate according to the thickness of the resin sheet.

For example, in the following Patent Document 1, in the extrusion molding of a resin sheet composed of three cooling rollers, a predetermined thickness is obtained by pressing and sandwiching with a pair of rollers that first contact each other, and then further resin sheet There is disclosed a method for obtaining a resin sheet having an excellent appearance by optimizing the temperature and pressing and clamping with a pair of rollers. In Patent Documents 2 and 3 below, the resin sheet is pressed and sandwiched by only a pair of rollers that first contact the molten resin sheet, and the cooling roller that contacts last does not pressurize, A method for obtaining an excellent resin sheet is described.
Japanese Patent Laid-Open No. 10-100230 Japanese Examined Patent Publication No. 2-61899 JP-A-8-25458

  However, the production methods described in Patent Documents 1 to 3 relate to extrusion molding of a flat resin sheet, and have not been described about a method of producing an uneven resin sheet having a thickness in the width direction. . The manufacture of the uneven thickness resin sheet is made up of three cooling rollers, a nip roller, a mold roller, and a peeling roller. If the resin sheet is pressed and sandwiched between the mold roller and the release roller, the uneven thickness resin sheet has a width. The resin sheet has a thickness distribution in the direction, and the temperature of the resin sheet is high in the thick part and low in the thin part, so that there is a problem that streaks occur at this boundary. On the contrary, if the clearance between the mold roller and the peeling roller is excessively widened, air is caught in the gap between the resin sheet and the peeling roller, which causes a problem of appearance failure.

  This invention is made | formed in view of such a situation, and it aims at providing the manufacturing method of the uneven thickness resin sheet which is excellent in an external appearance.

  In order to achieve the above object, claim 1 of the present invention is an extrusion process for extruding molten resin from a die into a sheet, and sandwiching the extruded molten resin sheet between a mold roller and a nip roller, and the processed shape of the surface of the mold roller A sheet forming step of forming a resin sheet by transferring the resin sheet to the molten resin sheet, and cooling and solidifying; a peeling step of peeling the resin sheet from a peeling roller; and a transporting step of pulling and transporting the resin sheet by a take-up roller; When the maximum value of the clearance between the nip roller and the mold roller in the width direction of the resin sheet is a [mm], and the maximum value of the clearance between the mold roller and the peeling roller is b [mm], And b satisfy a ≦ b ≦ a + 0.3, and a method for producing an uneven thickness resin sheet is provided.

  According to the first aspect, since the lower limit of the clearance b between the mold roller and the peeling roller is equal to or larger than the clearance a between the nip roller and the mold roller, the resin sheet is not pressed by the mold roller and the peeling roller. Further, since the upper limit is only (a + 0.3) or less and 0.3 mm wider than the film thickness a of the resin sheet formed by the nip roller and the mold roller, air is not entrained, so that appearance defects are suppressed. A good uneven thickness resin sheet can be produced.

  In the present invention, since the inverted mold of the uneven thickness resin sheet to be formed is formed on the mold roller, the clearance between the mold roller, the nip roller, and the peeling roller is different in the width direction. Therefore, in the present invention, the maximum clearance between the mold roller and the nip roller in the width direction is a, and the clearance between the mold roller and the peeling roller is b.

  A second aspect is characterized in that, in the first aspect, the difference in thickness between the thickest portion and the thinnest portion of the thickness distribution in the width direction of the resin sheet is 0.5 mm or more and 5 mm or less.

  According to claim 2, the difference in thickness between the thickest part and the thinnest part of the thickness distribution in the width direction of the resin sheet is 0.5 mm or more and 5 mm or less, so that the resin between the mold roller and the nip roller has a preferable clearance. The entire sheet can be conveyed.

  A third aspect is characterized in that, in the first or second aspect, the thickness distribution in the width direction of the resin sheet has a periodicity of a pitch of 200 mm or more.

  According to the present invention, by setting the maximum clearance between the mold roller and the nip roller in the width direction within the above range, the thickness distribution in the width direction of the resin sheet can be applied to a resin sheet having a periodicity with a pitch of 200 mm or more. It can be used suitably.

  According to the manufacturing method of the uneven thickness resin sheet of this invention, the uneven thickness resin sheet excellent in the external appearance by which generation | occurrence | production of planar defect was suppressed can be manufactured.

  Hereinafter, preferred embodiments of a method for producing an uneven thickness resin sheet according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is an overall process diagram of a method for producing a resin sheet according to the present invention, and FIG. 2 is a conceptual diagram showing an apparatus configuration in each process.

  As shown in FIG. 1, the resin sheet manufacturing method of the present invention mainly includes a raw material process 100 for measuring and mixing raw materials, an extrusion process 112 for continuously extruding molten resin into a sheet (band), and extrusion. The molten resin sheet 14a is cooled and solidified while being molded, a sheet forming step 114, a peeling step 115 for peeling the resin sheet 14, a slow cooling step 116 for gradually cooling the solidified resin sheet 14, and a resin sheet 14 And a cutting / cutting step 124 for cutting to a predetermined size (length / width).

  Hereinafter, the main structure of the resin sheet manufacturing apparatus to which the present invention is applied will be described with reference to FIG.

  As shown in FIG. 2, in the raw material process 100, the raw resin and additive sent from the raw material silo 128 (or raw material tank) and additive silo 130 (or additive tank) to the automatic weighing machine 132 are automatically measured and mixed. In the vessel 134, the raw material resin and the additive are mixed at a predetermined ratio.

  As the resin material of the raw material resin applied to the present invention, a thermoplastic resin can be used, for example, polymethyl methacrylate resin (PMMA), polycarbonate resin (PC), polystyrene resin (PS), MS resin, AS resin. , Polypropylene resin (PP), polyethylene resin (PE), polyethylene terephthalate resin (PET), polyvinyl chloride resin (PVC), thermoplastic elastomer, or a copolymer thereof, cycloolefin polymer, and the like.

  Further, these thermoplastic resins may contain light diffusing particles. Examples of the light diffusing particles include inorganic materials such as silicone, silica, calcium carbonate, barium sulfate, aluminum hydroxide, titanium oxide, glass beads, and calcium silicate. Examples thereof include particles and polymethyl methacrylate particles. When adding scattering particles, first, master pellets in which scattering particles are added to a raw material resin at a concentration higher than a predetermined concentration are manufactured by a granulator. Next, by suitably adopting the master batch method, the master pellets to which the scattering particles are added at a higher concentration than the predetermined concentration and the base pellets to which the scattering particles are not added are mixed at a predetermined ratio by the mixer 134. The same applies when additives other than the scattering particles are added.

  The raw resin appropriately weighed and mixed in the raw material process 100 is sent to the extrusion process 112.

  In the extrusion step 112, the raw material resin mixed in the mixer 134 is charged into the extruder 138 through the hopper 136. The raw material resin is melted while being kneaded by the extruder 138. The extruder 138 may be either a single-screw extruder or a multi-screw extruder, and preferably includes a vent function that evacuates the interior of the extruder 138. The raw material resin melted by the extruder 138 is sent to a die 12 (for example, a T die) through a supply pipe 142 by a metering pump 140 such as a screw pump or a gear pump. The molten resin sheet 14 a extruded from the die 12 into a sheet is then sent to the sheet forming step 114.

  In the sheet forming step 114, the molten resin sheet 14 a extruded from the die 12 is sandwiched between the mold roller 16 and the nip roller 18. The resin sheet 14 is cooled and solidified while being formed into a shape having a thickness distribution in the width direction. The solidified resin sheet 14 is peeled off by the peeling roller 20 (peeling step). The resin sheet 14 that has undergone the sheet forming step 114 is then sent to a slow cooling step 116.

  The slow cooling step (or annealing step) 116 is provided in order to prevent a rapid temperature change of the resin sheet 14 downstream of the peeling roller 20. When a sudden temperature change occurs in the resin sheet 14, for example, the inside of the resin sheet 14 becomes a plastic state despite the fact that the vicinity of the surface of the resin sheet 14 is in an elastic state. The surface shape of the sheet 14 may be deteriorated. Further, when a temperature difference is generated between the front and back surfaces of the resin sheet 14, the resin sheet 14 is likely to warp. In particular, when the resin sheet 14 has a thickness distribution in the width direction as in the sheet cross-sectional shape of FIG. 3A, the temperature distribution in the width direction becomes large and the resin sheet 14 is likely to warp.

  The slow cooling step 116 is provided with a tunnel-like slow cooling zone 154 (or annealing zone) having an inlet and an outlet.

  The heating means provided in the first half of the slow cooling zone 154 includes a structure in which air (hot air) whose temperature is controlled from a plurality of nozzles is jetted toward the resin sheet 14, a nichrome wire heater, an infrared heater, a dielectric heating means, etc. Various known means such as a structure for heating the resin sheet 14 can be employed, and the resin sheet can be prevented from being rapidly cooled.

  In addition, when the resin sheet 14 is slowly cooled and conveyed, an external force is applied to the resin sheet 14 in the first half of the slow cooling zone 154 so that the resin sheet 14 is not warped. In order to hold, shape holding means (not shown) can be provided.

  The resin sheet 14 that has passed through the slow cooling step 116 is conveyed to the cutting step 124 by the resin sheet 14 being pulled by the take-up roller 24 (conveying step 117).

  The cutting step 124 is a step of cutting the resin sheet 14 to a predetermined length. Moreover, it can also have the process of excising the width direction both ends (ear part) of the resin sheet 14. FIG. As the cutting means 174, a laser cutter, an electron beam cutting, an ultrasonic cutter, or the like can be used. A guillotine-type cutting means composed of a receiving blade and a pressing blade can also be used.

  Further, when the shape formed on the resin sheet has a plurality of thick portions, the cutting step 124 can also include a step of cutting in the conveyance direction at the joint of the shape.

  Moreover, although the resin sheet 14 is shape | molded by the predetermined | prescribed shape in the sheet | seat shaping | molding process 114, both edge parts of the resin sheet 14 become worse in dimensional accuracy compared with a center part in the shape. Moreover, since residual distortion also becomes large, it is preferable to cut | disconnect. The cut part is preferably cut at 20 to 30 mm at both ends of the resin sheet 14. As shown in FIG. 2, both edge portions of the resin sheet can be cut before cutting the resin sheet in a direction perpendicular to the conveying direction, or after cutting the sheet into a predetermined shape, both ends are cut. May be.

  A part of the cut resin sheet 14 is collected in a collection box 176, and the collected resin is discarded or reused.

  The cut sheet resin sheet 14 is conveyed to the next processing by a conveyor belt 196 driven by a roller 194 and is not displaced during traveling by the drum-shaped member 192 from the width direction of the resin sheet 14. Is held down.

  Next, among the above steps, details of the sheet forming step 114 that characterizes the present invention will be described with reference to FIGS.

  The resin sheet production line 10 includes a die 12 for shaping the raw material resin melted by the extruder 138 into a sheet shape, a mold roller 16 having an uneven thickness formed on the surface, and a mold roller 16 facing the mold roller 16. The nip roller 18 is formed, the peeling roller 20 is disposed opposite to the mold roller 16, and the heating device 22 that controls the temperature of the resin sheet 14.

  The sheet-like molten resin sheet 14 a extruded from the die 12 is clamped between the mold roller 16 and the nip roller 18 disposed so as to face the mold roller 16, and the uneven-type inverted mold on the surface of the mold roller 16 is transferred to the resin sheet 14. Then, the resin sheet 14 is gradually cooled by being wound around a peeling roller 20 disposed opposite to the mold roller 16, and is conveyed in a state where distortion is removed.

  In the present invention, by arranging the clearance between the nip roller and the mold roller and the clearance between the mold roller and the peeling roller so as to have a predetermined relationship, it is possible to manufacture an uneven-thickness resin sheet excellent in appearance.

  FIG. 5 is a sectional view seen from the die 12 side of the mold roller 16, the nip roller 18, and the peeling roller 20 when the manufactured uneven thickness resin sheet has the shape shown in FIG. Since this invention is manufacture of the uneven thickness resin sheet, the reverse type | mold of the uneven thickness resin sheet formed is formed in the type | mold roller. Therefore, since the depth of the mold roller varies in the width direction, in the present invention, a relational expression is defined for the maximum clearance.

  Specifically, in the case of the mold roller 16 shown in FIG. 5, the clearance between the mold roller 16 and the nip roller 18 becomes the maximum value at the center of the roller in the width direction, and this is the clearance a, and similarly the clearance between the mold roller 16 and the peeling roller 20. Is the maximum value in the central portion of the roller in the width direction, this is defined as clearance b, and each roller is arranged so as to satisfy a ≦ b ≦ a + 0.3. By arranging the roller so as to satisfy the above conditions, the thickness of the uneven thickness resin sheet can be determined by the clearance between the nip roller and the mold lahr, and the subsequent mold roller and the peeling roller are not pressurized. And since air is not caught between a peeling roller and a resin sheet, a film with a favorable external appearance can be manufactured. It is preferable that the maximum value a of the clearance between the nip roller and the mold roller and the maximum value b of the clearance between the mold roller and the peeling roller further satisfy the relationship of a ≦ b ≦ a + 0.2.

  In the production of this resin sheet, the extrusion speed of the resin sheet 14 of 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. In addition, it is preferable to control the speed unevenness of each roller within 1% with respect to the set value.

  The pressing pressure of the nip roller 18 against the mold roller 16 should be 0 to 200 kN / m (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). Is more preferable, and 0 to 100 kN / m (kgf / cm) is more preferable.

  Although the peripheral speed of a type | mold roller is not specifically limited, It is preferable that they are 1.0 m / min or more and 5.0 m / min or less, More preferably, they are 1.2 m / min or more and 2.0 m / min or less. By setting the peripheral speed of the mold roller within the above range, the time for nipping between the mold roller and the nip roller and the time for cooling and solidifying with the mold roller can be adjusted to the desired time, so a good sheet is produced. can do.

  Moreover, it is preferable that the circumferential speed of the peeling roller and the mold roller is larger than the circumferential speed of the outermost diameter of the mold roller. By increasing the peripheral speed of the outermost diameter of the peeling roller, the uneven thickness resin sheet formed by the mold roller and the nip roller can be conveyed while being pulled by the peeling roller, so generation of wrinkles on the uneven thickness resin sheet is prevented. Can be suppressed.

  The resin sheet 14 peeled from the mold roller 16 by the peeling roller 20 is gradually cooled in the slow cooling zone 154. The cooled resin sheet 14 is heated by the heating device 22 from the lower side of the resin sheet 14 (the side where the uneven resin sheet protrusion is not formed) as necessary, and is a cut portion of the resin sheet 14. The end portion is softened and the generation of chips when cut by the cutting means 174 is suppressed. In addition, even after cutting the end portion of the resin sheet 14, when the resin sheet 14 is heated by the heating device 22 to be cut in the conveyance direction of the resin sheet 14, in the case of being cut in the direction orthogonal to the conveyance direction Can be cut while suppressing the generation of chips.

  The features of the present invention will be specifically described below with reference to examples and comparative examples. Note that materials, processing contents, processing procedures, and the like in the following embodiments can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
The uneven thickness resin sheet was manufactured using the apparatus shown in FIG.

  PMMA (manufactured by Asahi Kasei Co., Ltd., 80NH, glass transition temperature 110 ° C.) is extruded from a T die set at a temperature of 255 ° C., passed through a nip roller, a mold roller having a shape as shown in FIG. 5, a peeling roller, and a slow cooling zone. Form a sheet and cut both ends of the uneven thickness resin sheet, and the cross-sectional shape in the sheet width direction is 594 mm wide, the thinnest part 2.0 mm, and the thickest part 3.8 mm as shown in FIG. A sheet was obtained.

  In the sheet forming process, the surface temperatures of the nip roller, the mold roller, and the peeling roller are 70 ° C., 75 ° C., and 80 ° C., respectively, the roller diameter of the nip roller is φ350 mm, the roller diameter of the peeling roller is φ500 mm, and the thick roller forming portion The diameter of the roller was φ345.6 mm, the roller diameter of the thin-walled portion was φ349.2 mm, and the roller diameter (outermost diameter) of the non-contact portion with the resin sheet was φ350 mm.

  At this time, the clearance between the nip roller and the mold roller is 3.90 mm at the maximum portion at the center of the roller and 1.70 mm at the minimum portion at the end of the roller, and the clearance between the mold roller and the peeling roller is 4 at the maximum portion at the center of the roller. 0.000 mm, and 1.80 mm at the minimum end of the roller. The peripheral speeds (outermost diameters) of the nip roller, the mold roller, and the peeling roller were 1.205 m / min, 1.209 m / min, and 1.230 m / min, respectively. The nip roller, mold roller, and peeling roller were subjected to hard chrome plating.

  As shown in FIG. 4, the uneven thickness resin sheet is manufactured by placing a far-infrared ceramic heater at a surface temperature of 500 mm at a position 50 mm away from the surface of the sheet opposite to the surface in contact with the mold roller and the peeling roller. The temperature was set at a temperature of 150 ° C., and each 150 mm range from the both ends of the sheet was heated for 20 seconds during contact with the mold roller and for 15 seconds during contact with the peeling roller.

  An ultrasonic cutter was installed at a position 200 mm from the peeling roller, and the 2.0 mm thick portions at both ends of the resin sheet were cut to produce an uneven thickness resin sheet.

  At the time of the above clearance, a sheet having a good appearance could be obtained.

[Example 2]
Under the conditions of Example 1, when the maximum clearance between the nip roller and the mold roller (roller center) was 3.90 mm and the maximum clearance between the mold roller and the peeling roller (roller center) was 3.90 mm, a sheet having a good appearance was obtained. I was able to.

[Example 3]
Under the conditions of Example 1, when the maximum clearance between the nip roller and the mold roller (roller center) is 3.90 mm and the maximum clearance between the mold roller and the peeling roller (roller center) is 4.10 mm, a sheet having a good appearance is obtained. I was able to.

[Example 4]
Under the conditions of Example 1, the peripheral speeds (outermost diameters) of the nip roller, the mold roller, and the peeling roller were 0.753 m / min, 0.755 m / min, and 0.765 m / min, respectively. The surface temperature of each roller is 70 ° C., 90 ° C., and 95 ° C., the maximum clearance between the nip roller and the mold roller (roller center) is 3.90 mm, and the maximum clearance between the mold roller and the peeling roller (roller center) is 3.94 mm. As shown in FIG. 4, the far-infrared ceramic heater is set at a surface temperature of 350 ° C. at a position 50 mm away from the surface of the sheet opposite to the surface in contact with the mold roller and the peeling roller. A range of 150 mm from both ends was heated for 30 seconds during contact with the mold roller and for 25 seconds during contact with the peeling roller.

  An ultrasonic cutter was installed at a position 200 mm from the peeling roller, and the 2.0 mm thick portions at both ends of the resin sheet were cut to produce an uneven thickness resin sheet.

  At the time of the above clearance, a sheet having a good appearance could be obtained.

[Example 5]
Under the conditions of Example 4, when the maximum clearance between the nip roller and the mold roller (roller center) was 3.90 mm and the maximum clearance between the mold roller and the peeling roller (roller center) was 3.90 mm, a sheet having a good appearance was obtained. I was able to.

[Example 6]
Under the conditions of Example 4, when the maximum clearance between the nip roller and the mold roller (roller center) is 3.90 mm and the maximum clearance between the mold roller and the peeling roller (roller center) is 4.10 mm, a sheet having a good appearance can be obtained. I was able to.

[Comparative Example 1]
Under the conditions of Example 1, the maximum clearance (roller center) between the nip roller and the mold roller was 3.90 mm, and the maximum clearance between the mold roller and the peeling roller (roller center) was 3.85 mm. Streaks have occurred at both ends.

[Comparative Example 2]
Under the conditions of Example 1, the maximum clearance between the nip roller and the mold roller (roller center) was 3.90 mm, and the maximum clearance between the mold roller and the release roller (roller center) was 4.25 mm. As a result, air entrainment occurred, and traces of air spots were transferred to the surface of the resin sheet, resulting in deterioration of the surface shape.

[Comparative Example 3]
Under the conditions of Example 1, the maximum clearance (roller center) between the nip roller and the mold roller was 3.90 mm, and the maximum clearance (roller center) between the mold roller and the release roller was 4.3 mm. The air entrained in the gap between the resin sheet and the spotted air marks were transferred to the surface of the resin sheet, and the surface condition deteriorated.

[Comparative Example 4]
Under the conditions of Example 4, the maximum clearance (center of the roller) between the nip roller and the mold roller was 3.90 mm, and the maximum clearance between the mold roller and the peeling roller (roller center) was 3.85 mm. Streaks have occurred at both ends.

[Comparative Example 5]
Under the conditions of Example 4, the maximum clearance between the nip roller and the mold roller (roller center) was 3.90 mm, and the maximum clearance between the mold roller and the release roller (roller center) was 4.30 mm. Air entrainment occurred, and the traces of air spots were transferred to the surface of the resin sheet, resulting in deterioration of the spot surface.

  The results of Example 1-6 and Comparative Example 1-5 are shown in FIG. In addition, the symbol in a figure shows the following meaning.

<Streak>
○ ・ ・ ・ No streak and good appearance × ・ ・ ・ Surface defect that looks like a streak
○: No speckled pattern, good appearance Δ: Spotted pattern is generated near the center of the sheet on the surface of the sheet in contact with the peeling roll ×: Entirely on the surface of the sheet in contact with the peeling roll As shown in FIG. 6, in Example 1-6 in which the clearance b between the mold roller and the peeling roller is greater than or equal to the clearance a between the nip roller and the mold roller (a + 0.3), a good sheet is formed. Could be manufactured. In Comparative Examples 1 and 4 where the clearance b is narrower than the clearance a, streaks occur, and in Comparative Examples 2, 3 and 5 where the clearance b is wider than the clearance a + 0.3, as the clearance b is widened, spots appear. It was noticeable.

  In addition, it was confirmed that a good sheet could be obtained at a peripheral speed of the mold roller of either 1.209 m / min or 0.755 m / min, and that the speed of the mold roller was not affected.

It is process drawing explaining the flow of the manufacturing method of the uneven thickness resin sheet to which this invention is applied. It is a conceptual diagram of the manufacturing apparatus of the uneven thickness resin sheet to which this invention is applied. It is sectional drawing which shows an example of the shape of an uneven thickness resin sheet. It is a block diagram which shows the sheet | seat shaping | molding process, peeling process, slow cooling process, and cutting process of the manufacturing apparatus of an uneven thickness resin sheet. It is sectional drawing which shows an example of the shape of a type | mold roller. It is a table | surface figure which shows the result of an Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Production line, 12 ... Die, 14 ... Resin sheet, 14a ... Molten resin sheet, 16 ... Mold roller, 18 ... Nip roller, 20 ... Peeling roller, 22 ... Heating device, 24 ... Take-off roller, 100 ... Raw material process, 112 ... extrusion process, 114 ... sheet forming process, 115 ... peeling process, 116 ... slow cooling process, 117 ... conveying process, 124 ... cutting process, 126 ... loading process, 128 ... raw material silo, 130 ... additive silo, 132 ... automatic Weighing machine, 134 ... mixer, 136 ... raw material hopper, 138 ... extruder, 140 ... metering pump, 142 ... supply pipe, 154 ... slow cooling zone, 174 ... cutting means, 176 ... collection box, 192 ... drum shape 194 ... roller, 196 ... conveyor belt

Claims (3)

An extrusion process of extruding the molten resin from the die into a sheet,
A sheet molding step of molding the resin sheet by sandwiching the extruded molten resin sheet between a mold roller and a nip roller, transferring the processed shape of the surface of the mold roller to the molten resin sheet, and cooling and solidifying;
A peeling step of peeling the resin sheet from the peeling roller;
A conveying step of pulling and conveying the resin sheet with a take-off roller,
When the maximum value of the clearance between the nip roller and the mold roller in the width direction of the resin sheet is a [mm] and the maximum value of the clearance between the mold roller and the peeling roller is b [mm], a and b are a ≦ a The manufacturing method of the uneven thickness resin sheet characterized by satisfy | filling b <= a + 0.3.   The method for producing an uneven thickness resin sheet according to claim 1, wherein a difference in thickness between the thickest part and the thinnest part of the thickness distribution in the width direction of the resin sheet is 0.5 mm or more and 5 mm or less.   The thickness distribution in the width direction of the said resin sheet has the periodicity of the pitch of 200 mm or more, The manufacturing method of the uneven thickness resin sheet of Claim 1 or 2 characterized by the above-mentioned.

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