Resin sheet using acrylic resin and method for producing the same

Abstract

To produce and provide a resin sheet having superior processability using a predetermined acrylic resin.SOLUTION: A resin sheet is obtained by kneading 10 wt.% to less than 40 wt.% of an acrylic resin having a polymerization degree of 1000-20000 and more than 60 wt.% to 90 wt.% of a carbonyl-group-containing polymer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a resin sheet using an acrylic resin and a method for producing the same. [Background technology]

[0002] An acrylic resin (for example, an acrylic-based soft resin) is contained in a vinylidene chloride resin together with a plasticizer, etc., and is used as a raw material for sheets, etc., as a vinylidene chloride resin composition (Patent Document 1). In Patent Document 1, by containing an acrylic-based soft resin in a vinylidene chloride resin composition, the range of flexibility when processed into sheets and the range of processing conditions in general-purpose processing equipment are expanded while maintaining weather resistance and cold resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-177849 Summary of the Invention [Problem to be solved by the invention]

[0004] Acrylic resin is contained in vinylidene chloride resin and used as a raw material for sheets, and is also used as a raw material for so-called acrylic boards. Acrylic boards are discarded after use, but in light of recent environmental concerns, reuse of waste acrylic boards has been considered, and they are being recycled into acrylic boards. However, recycling of waste acrylic boards into sheets has not been carried out. Because waste acrylic boards are made from acrylic resin, they are hard and brittle by nature and are not suitable for sheeting. On the other hand, even if polypropylene or polyester is added to acrylic resin to impart flexibility, it is difficult to achieve the desired flexibility.

[0005] An object of the present invention is to provide a resin sheet having excellent processability using acrylic resin, for example, waste acrylic plate, i.e., waste acrylic resin, and a method for producing the same. [Means for solving the problem]

[0006] According to an embodiment of the present invention, there is provided a resin sheet produced by kneading 10% to less than 40% by weight of an acrylic resin having a degree of polymerization of 1000 to 20000 with more than 60% to 90% by weight of a carbonyl group-containing polymer. The acrylic resin may be waste acrylic resin.

[0007] The carbonyl group-containing polymer may be any one of ethylene-vinyl acetate copolymer, ethylene-allyl acetate copolymer, ethylene-vinyl propionate copolymer, ethylene-allyl propionate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-ethyl methacrylate copolymer. The carbonyl group-containing polymer may also be a waste sheet formed of ethylene-vinyl acetate copolymer.

[0008] According to another aspect of the present invention, there is provided a method for producing a resin sheet, comprising: a kneading step of kneading 10% by weight to less than 40% by weight of an acrylic resin having a degree of polymerization of 1,000 to 20,000 with more than 60% by weight to 90% by weight of a carbonyl group-containing polymer; and a sheet forming step of forming the kneaded product obtained by the kneading step into a sheet shape by at least one of calendaring, laminating, and embossing. [Effects of the Invention]

[0009] According to the present invention, a resin sheet having improved processability, which allows for flexible calendering and embossing, and a method for manufacturing the same are provided. In addition, when using waste acrylic material, for example, the waste acrylic material is recycled into the resin sheet, which is also useful from the viewpoint of environmental protection.

[0010] Furthermore, by kneading 10% to less than 40% by weight of an acrylic resin having a degree of polymerization of 1,000 to 20,000 with more than 60% to 90% by weight of a carbonyl group-containing polymer, a resin sheet with excellent processability can be produced. Furthermore, by embossing the resin sheet, the usefulness of the resin sheet can be improved. Furthermore, by laminating a sheet having the same or a different composition as the resin sheet to one or both of the front and back surfaces of the resin sheet, it is possible to impart functions such as improving the durability and weather resistance of the resin sheet. Furthermore, by laminating a sheet having the same or a different composition as the resin sheet to one or both of the front and back surfaces of the resin sheet, it is possible to impart functions such as improving the durability and weather resistance of the resin sheet. Furthermore, by laminating a sheet having the same or a different composition as the resin sheet to one or both of the front and back surfaces of the resin sheet, and then embossing the resin sheet and the sheet having the same or a different composition as the resin sheet, it is possible to impart functions such as improving the durability and weather resistance of the resin sheet while improving the usefulness of the resin sheet. Furthermore, by kneading the waste acrylic resin and the carbonyl group-containing polymer while heating them, a resin kneaded product can be produced more easily.

[0011] In addition, in an embodiment in which the carbonyl group-containing polymer is any one of ethylene-vinyl acetate copolymer, ethylene-allyl acetate copolymer, ethylene-vinyl propionate copolymer, ethylene-allyl propionate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-ethyl methacrylate copolymer, a resin sheet can be appropriately produced. In addition, in an embodiment in which the carbonyl group-containing polymer is a waste sheet formed of ethylene-vinyl acetate copolymer, a resin sheet can be appropriately produced. In addition, in an embodiment in which, for example, plate-shaped waste acrylic resin is cut to a predetermined size and introduced into a kneader, the waste acrylic resin and the carbonyl group-containing polymer can be kneaded in a short time. [Brief explanation of the drawings]

[0012] [Figure 1] 3 is a flowchart relating to a method for manufacturing a resin sheet according to the present embodiment. [Figure 2] FIG. 2 is a schematic perspective view showing an example of a kneader used in the method for producing a resin sheet according to the present embodiment. [Figure 3] FIG. 2 is a schematic perspective view showing an example of a calendar molding machine used in the resin sheet manufacturing method according to the present embodiment. [Figure 4] FIG. 1 is a schematic perspective view showing an example of an embossing machine that embosses a resin sheet manufactured by a resin sheet manufacturing method according to the present embodiment. [Figure 5] 1 is a schematic perspective view showing an example of a laminating machine that laminates a resin sheet manufactured by a resin sheet manufacturing method according to the present embodiment. FIG. [Figure 6] 10 is a graph showing the relationship between tensile force and displacement on a resin sheet according to a test example. [Figure 7] 1 is a table showing physical properties of resin sheets according to examples and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below. In addition, in the drawings, some parts are omitted to facilitate understanding of the embodiments. Furthermore, the drawings are scaled appropriately, such as by enlarging or emphasizing certain parts, and the actual product may differ in size and shape. In the following drawings, directions in the drawings may be explained using an XYZ Cartesian coordinate system. In this XYZ Cartesian coordinate system, a plane parallel to the horizontal plane is defined as the XY plane. A direction parallel to the XY plane is defined as the X direction, and a direction perpendicular to the X direction is defined as the Y direction. Furthermore, a direction perpendicular to the XY plane is defined as the Z direction (height direction). The X, Y, and Z directions will be explained assuming that the direction indicated by the arrow in the drawing is the + direction, and the direction opposite to the arrow is the - direction.

[0014] Additionally, in the JIS "Packaging Terminology" standard, "sheet" refers to a thin plastic plate with a thickness of 250 μm or more, and "film" refers to a plastic membrane with a thickness of less than 250 μm. In this specification, there is no strict distinction between sheet and film, and the term "sheet" is used to include film. Note that the hardness of the sheet is not limited to soft, semi-hard, or hard. In other words, plate-like forms are also included in the term "sheet."

[0015] [Embodiment] FIG. 1 is a flowchart of a method for producing a resin sheet according to this embodiment. As shown in FIG. 1, first, plate-shaped waste acrylic resin, for example, discarded acrylic plate, is cut to an appropriate size (step S01). It is optional whether or not to perform step S01, and step S01 does not have to be performed. The size after cutting is, for example, approximately 10 cm square, but this can be changed as appropriate depending on the size of the kneading machine used in the next step (kneading step). When a large kneading machine such as a Banbury mixer is used in the kneading step, the step of cutting the plate-shaped waste acrylic resin to an appropriate size may be omitted. In this specification, the term "waste acrylic resin" also refers to plate-shaped waste acrylic resin, cut pieces of plate-shaped waste acrylic resin, and granular or powdery material made from plate-shaped waste acrylic resin.

[0016] FIG. 2 is a schematic perspective view showing an example of a kneader 1 used in a method for producing a resin sheet. The kneader 1 includes a rectangular case 10 with an open top, a pair of rollers 11A and 11B provided inside the case 10, and a heating device (not shown). The kneader 1 is, for example, a Banbury mixer. The kneader 1 kneads raw materials, resin (waste acrylic resin) R1 and resin (carbonyl group-containing polymer) R2, to produce a resin kneaded product R. The number of resins to be kneaded is not limited to two, and may be two or more. Depending on the type of resin, resins R1 and R2 may be heated by a heating device (not shown) when kneading.

[0017] The case 10 is provided to surround the rollers 11A and 11B and has a discharge port (not shown) on the bottom surface. The resins R1 and R2 are poured into the case 10 from the top surface and kneaded by the rollers 11A and 11B. The discharge port of the case 10 is closed when the resins R1 and R2 are being kneaded. The resin mixture R produced in the case 10 is poured into the next process device through a discharge port (not shown). The rollers 11A and 11B are arranged to extend in the Y direction with a gap between them in the X direction. The rollers 11A and 11B rotate in opposite directions to each other to knead the resins R1 and R2. The rotation speeds of the rollers 11A and 11B are set appropriately depending on the types of resins R1 and R2, the amounts poured, etc.

[0018] In this embodiment, resin R1 may be, for example, polymethyl methacrylate (PMMA), which is a component of discarded acrylic sheets. Resin R2 may be, for example, a carbonyl group-containing polymer. Examples of carbonyl group-containing polymers include ethylene-vinyl acetate copolymer (hereinafter sometimes referred to as "EVA"), ethylene-allyl acetate copolymer, ethylene-vinyl propionate copolymer, ethylene-allyl propionate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-ethyl methacrylate copolymer. These may be in the form of a sheet-like product, or in the form of granules or powder.

[0019] When kneading the waste acrylic resin with the carbonyl group-containing polymer, it is preferable to knead 10% to less than 40% by weight of the waste acrylic resin with more than 60% to 90% by weight of the carbonyl group-containing polymer, and it is particularly preferable to knead 20 to 30% by weight of the waste acrylic resin with 80 to 70% by weight of the carbonyl group-containing polymer. The degree of polymerization of the acrylic resin in the waste acrylic resin is preferably 1,000 to 20,000. It is also preferable to knead while warming.

[0020] In the flowchart shown in FIG. 1 , after step S01, waste acrylic resin R1 and carbonyl group-containing polymer R2 are introduced into a kneader 1 (step S02). Subsequently, the waste acrylic resin R1 and the carbonyl group-containing polymer R2 are kneaded while being heated to gel the resin mixture R (step S03). The materials may be introduced into the kneader 1 in the following order: the waste acrylic resin R1 followed by the carbonyl group-containing polymer R2, or the carbonyl group-containing polymer R2 followed by the waste acrylic resin R1. Alternatively, the waste acrylic resin R1 and the carbonyl group-containing polymer R2 may be introduced simultaneously. The waste acrylic resin R1 may be prepared by cutting a sheet of waste acrylic resin into an appropriate size using a cutter or shearing machine. Known cutters or shearing machines can be used. Examples of the cutter include a rotary cutter and a shearing machine. When the carbonyl group-containing polymer R2 is EVA, a waste sheet made of EVA may be used. Waste EVA sheets can be used as recycled raw materials in the same way as waste acrylic resin.

[0021] FIG. 3 is a schematic perspective view showing an example of a calendering machine 3 used in the manufacturing method of the resin sheet S1 according to this embodiment. The molding method for manufacturing the resin sheet S1 includes, but is not limited to, calendering, T-die extrusion, inflation molding, and the like. However, calendering using a calendering machine is preferred. This is because calendering using the calendering machine 3 is advantageous in that it can efficiently produce wide sheets. A calendering machine generally has at least a pair of metal rolls arranged with their surfaces adjacent to each other, and resin or the like is molded into a sheet by passing through the gap between the metal rolls. By adjusting the size of this gap, sheets of various thicknesses can be obtained. Furthermore, the rotation speeds of the metal rolls are generally set differently, which allows shear force to be applied to the resin composition. The device for manufacturing the resin sheet S1 is not limited to the calendering machine 3, but may also be a T-die extrusion machine, inflation molding machine, or the like.

[0022] In the flowchart shown in FIG. 1, after step S03, the gelled resin kneaded material R is fed into a calendar molding machine 3 (step S04). Then, the resin kneaded material R is formed into a sheet by the calendar molding machine 3 (step S05). While being formed into a sheet, the resin kneaded material R is cooled to a temperature close to room temperature, and becomes a resin sheet S1. Then, the resin sheet S1 is wound into a roll by a winding device 31E, which will be described later (step S06).

[0023] The calendering machine 3 includes calender rolls 31A, 31B, 31C, and 31D, and a winding device 31E. The calender rolls 31A, 31B, 31C, and 31D rotate in the directions of the arrows shown in the figure, and cool the resin kneaded material R to near room temperature while forming it into a sheet. The temperature of the calender rolls 31A and the like is set appropriately depending on the type of resin kneaded material R. The calender rolls 31A and the like may each be equipped with a cooling device or a heating device. The winding device 31E winds up the resin sheet S1 by rotating its shaft in the direction of the arrow by a driving device (not shown).

[0024] The calender roll 31A and the calender roll 31B are arranged at a predetermined distance (gap) d1 in the X direction (horizontal direction). The distance d1 is set according to the thickness of the resin sheet S1 to be molded. The calender rolls 31B, 31C, and 31D are arranged at predetermined distances (gaps) d2 and d3 in the Z direction (height direction). The distances d2 and d3 are set according to the thickness of the resin sheet S1 to be molded. The calender roll 31D and the winding device 31E are arranged with a gap in the X direction (horizontal direction). A constant tension is applied to the resin sheet S1 by adjusting the rotation speeds of the calender roll 31D and the winding device 31E.

[0025] The resin kneaded material R is squeezed between the calendar rolls 31A and 31B and formed into a sheet-like material having a predetermined thickness. The formed sheet-like material is then further squeezed between the calendar rolls 31B and 31C and formed into an even thinner sheet-like material. The sheet-like material is then further squeezed between the calendar rolls 31C and 31D to become a resin sheet S1, which is then passed through, for example, a cooling device (not shown) and then taken up by a take-up device 31E to become a resin sheet roll RS1. It is optional whether or not a cooling device is provided.

[0026] In this embodiment, the calendering machine 3 has four calender rolls 31A, 31B, 31C, and 31D, but is not limited to this. The calendering machine 3 may have two, three, or five or more calender rolls.

[0027] In the flowchart shown in FIG. 1, after step S06, the resin sheet S1 is embossed (step S07). Whether or not step S07 is performed is optional, and step S07 does not have to be performed. FIG. 4 is a schematic perspective view showing an example of an embossing machine 4 that embosses the resin sheet S1. The embossing machine 4 includes a delivery roll 41A (resin sheet roll RS1), a bottom roll 41B, an embossing roll 41C, and a winding device 41D. The delivery roll 41A, the bottom roll 41B, and the embossing roll 41C are each disposed to extend in the Y direction. Furthermore, one or both of the bottom roll 41B and the embossing roll 41C are provided with a rotation drive device (not shown), and rotate in the direction of the arrow shown in the figure.

[0028] The winding device 41D winds up the resin sheet S2 while its shaft rotates in the direction of the arrow shown in the figure using a rotation drive device (not shown). The bottom roll 41B and the embossing roll 41C form the resin sheet S2 by embossing the resin sheet S1. The bottom roll 41B and the embossing roll 41C may be equipped with a heating device to set the roll surfaces to a predetermined temperature.

[0029] The embossing roll 41C has a concave-convex pattern on its roll surface. For example, when the resin sheet S1 is a resin mixture R of waste acrylic resin and EVA, the heated resin sheet S1 is passed through the embossing roll to form the concave-convex pattern. The temperatures of the bottom roll 41B and the embossing roll 41C are set appropriately depending on the type of resin sheet S1.

[0030] The resin sheet S1 passes through a distance d4 between the bottom roll 41B and the embossing roll 41C, and is sandwiched between the bottom roll 41B and the embossing roll 41C and heated at an appropriate temperature, thereby being embossed. The winding device 41D winds up the resin sheet S2 formed into a sheet shape while maintaining a constant tension. The resin sheet S2 wound up by the winding device 41D is taken out as a resin sheet roll RS2.

[0031] In the flowchart shown in Fig. 1, after step S06, lamination is performed on the resin sheet S1 (step S08). Whether or not step S08 is performed is optional, and step S08 does not have to be performed. Fig. 5 is a schematic perspective view showing an example of a laminating machine 5 that performs lamination by stacking a resin sheet (including a resin film) that is the resin sheet S3 on the surface of the resin sheet S1. Step S08 may be performed after step S07 or before step S07, or steps S07 and S08 may be performed simultaneously.

[0032] The resin sheet S3 may be a sheet having the same composition as or a different composition from the resin sheet S1. The laminating machine 5 includes a feed roll 51A (resin sheet roll RS1), a feed roll 51B (auxiliary sheet roll RS3), a laminating roll 51C, a pressure roll 51D, tension rolls 51E and 51F, and a winding device 51G.

[0033] The delivery roll 51A, delivery roll 51B, laminating roll 51C, pressure roll 51D, and tension rolls 51E and 51F are arranged to extend in the Y direction. The laminating roll 51C, pressure roll 51D, and tension rolls 51E and 51F are equipped with, for example, a rotation drive device (not shown) and rotate in the direction of the arrows. Four pressure rolls 51D are provided along the curved surface of the upper half of the laminating roll 51C, facing the laminating roll 51C. The winding device 51G winds up the laminated resin sheet S4 by rotating its shaft in the direction of the arrow using a rotation drive device (not shown).

[0034] Resin sheets S1 and S3 are drawn out from feed rolls 51A and 51B, respectively, and fed between laminating roll 51C and pressing roll 51D. Resin sheets S1 and S3 are sandwiched between laminating roll 51C and pressing roll 51D and overlapped, and are then heated by a heating device (not shown) to press and laminate the two sheets together. The heating temperature for resin sheets S1 and S3 is set appropriately depending on the type of resin sheet S1 and resin sheet S3.

[0035] Tension rolls 51E and 51F apply a certain tension to the resin sheet S4. A winding device 51G winds up the resin sheet S4 (sometimes referred to as a laminated sheet) that has been formed into a laminated sheet shape, to form a laminated sheet roll RS4. In this embodiment, the embossing process (step S07) and the lamination process (step S08) are performed separately, but they may also be performed simultaneously. For example, in FIG. 5, by replacing one of the pressing rolls 51D with an embossing roll (e.g., the embossing roll 41C in FIG. 4), it is possible to perform embossing while laminating.

[0036] In this embodiment, an example in which the resin sheet S3 is laminated on the front side of the resin sheet S1 has been described, but the resin sheet S3 may also be laminated on the back side of the resin sheet S1, or the resin sheet S3 may be laminated on both the front and back sides of the resin sheet S1. When laminating the resin sheet S3 on both the front and back sides of the resin sheet S1, another feed roll 51B (auxiliary sheet roll RS3) is disposed below the feed roll 51A (resin sheet roll RS1) in FIG. 5. When laminating both the front and back sides of the resin sheet S1, the resin sheets S3 on the front and back sides of the resin sheet S1 may have the same composition as the resin sheet S1, or may have different compositions.

[0037] Figure 6 is a graph (SS curve) showing the relationship between tensile force and displacement for a resin sheet according to a test example. For the test, 30% by weight of waste acrylic resin and 70% by weight of EVA were poured between 6-inch test rolls and formed into a sheet to produce a resin sheet. The 6-inch test rolls were a simple test calendar molding machine consisting of two rolls. Test pieces (JIS No. 3 test pieces) were cut from the resin rolls produced, and a test force (N) was applied as a tensile force using a tensile tester to measure the displacement (mm) of the test pieces. MD indicates the change when a test force is applied in the conveyance direction during resin sheet production, and TD indicates the change when a test force is applied in a direction perpendicular to the conveyance direction during resin sheet production.

[0038] As shown in Figure 6, when a test force of approximately 15 N to approximately 18 N was applied to the resin sheet in the machine direction (MD), the resin sheet displaced up to approximately 90 mm, and a test force of approximately 18 N to approximately 30 N was required for displacements of approximately 90 mm or more. The test force decreased for displacements of approximately 118 mm or more due to fracture of the test specimen. On the other hand, when a test force of approximately 12 N to approximately 15 N was applied to the resin sheet in the direction perpendicular to the machine direction (TD), the resin sheet displaced up to approximately 105 mm, and a test force of approximately 15 N to approximately 23 N was required for displacements of approximately 105 mm or more. The test force decreased for displacements of approximately 118 mm or more due to fracture of the test specimen. These test results confirmed that the resin sheet according to the test example is flexible and stretchable and does not easily fracture in both the machine direction (MD) and the direction perpendicular to the machine direction (TD).

[0039] Examples and comparative examples will be described below. Fig. 7 is a table showing the physical properties of the resin sheets in the examples and comparative examples.

[0040] [Example 1] A 6-inch test roll was set at a roll temperature of 160°C and was charged with waste acrylic resin and EVA (EV460 manufactured by Mitsui Dow Chemical Co.) at a weight ratio of 10:90 (acrylic content: 10 wt%). The mixture was mixed for 5 minutes and then formed into a 0.5 mm thick roll sheet using the roll sheet forming method. The resin sheet was then cut to the size of a JIS No. 3 test piece and subjected to a tensile test in the machine direction (MD) using a tensile tester. The surface of the resin sheet was also photographed with a camera to confirm its surface smoothness.

[0041] [Example 2] The procedure was the same as in Example 1, except that waste acrylic resin and EVA (EV460 manufactured by Mitsui Dow Chemical Company) were used so that the weight ratio of waste acrylic resin to EVA was 20:80 (acrylic added amount: 20 wt%).

[0042] [Example 3] The same procedure as in Example 1 was carried out except that waste acrylic resin and EVA (EV460 manufactured by Mitsui Dow Chemical Co.) were used so that the weight ratio of waste acrylic resin to EVA was 30:70 (acrylic additive amount 30 wt%).

[0043] [Example 4] The same procedure as in Example 1 was used except that waste acrylic resin and EVA (EV460 manufactured by Mitsui Dow Chemical Company) were used so that the weight ratio of waste acrylic resin to EVA was 40:60 (acrylic additive amount: 40 wt%).

[0044] [Example 5] The same procedure as in Example 1 was carried out except that waste acrylic resin and EVA (EV460 manufactured by Mitsui Dow Chemical Company) were used so that the weight ratio of waste acrylic resin to EVA was 50:50 (acrylic added amount: 50 wt%).

[0045] [Comparative Example 1] EVA (EV460 manufactured by Mitsui Dow Chemical Company) (acrylic content: 0 wt%) was placed in a Banbury mixer and kneaded while warming to form a gel, after which a resin sheet was produced using a calendar molding machine in the same manner as in Example 1. The resin sheet was then cut to the size of a JIS No. 3 test piece and subjected to a tensile test in the machine direction (MD) using a tensile tester in the same manner as in Example 1. The surface of the resin sheet was also photographed using a photographing device to confirm the surface smoothness.

[0046] As shown in FIG. 7, Examples 1 to 3 showed good results in both tensile strength and elongation. Examples 4 and 5 showed lower tensile strength and elongation than Examples 1 to 3. Furthermore, when the smoothness of the surface of the resin sheet was checked, Examples 1 and 2 had slight irregularities on the surface, but there was no problem with smoothness. Examples 3 to 5 had slight or almost no irregularities on the surface, and had high smoothness. Comparative Example 1 had many irregularities on the surface, and the smoothness was low.

[0047] That is, the resin sheets of Examples 1 to 5 have sufficient tensile strength and elongation, and are also smooth. In particular, the resin sheets of Examples 1 to 3 have high tensile strength and elongation, and are also sufficiently smooth. Therefore, the preferred weight ratios of waste acrylic and EVA are 10% to less than 40% by weight of waste acrylic resin and over 60% to 90% by weight of EVA. Furthermore, particularly preferred ranges are 20% to 30% by weight of waste acrylic resin and 70% to 80% by weight of EVA. Furthermore, the resin sheets of Examples 1 to 5 have high tensile strength and elongation, and are also smooth, making them easy to process.

[0048] As described above, the present embodiment and examples provide a method for manufacturing a resin sheet that has flexibility and improved processability, allowing for calendaring and embossing. Furthermore, since the resin sheet is made from recycled acrylic material, it is also useful from the perspective of environmental protection.

[0049] Although the embodiments and examples have been described above, the technical scope of the present invention is not limited to the above-described embodiments and examples. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above-described embodiments and examples. Furthermore, forms incorporating such modifications or improvements are also included within the technical scope of the present invention. One or more of the requirements described in the above-described embodiments and examples may be omitted. Furthermore, the requirements described in the above-described embodiments and examples may be combined as appropriate. Furthermore, the execution order of each process shown in the embodiments and examples can be implemented in any order, as long as the results of a previous process are not used in a subsequent process. Furthermore, even if the processes in the above-described embodiments and examples are described using terms such as "first," "next," and "followed" for convenience, it is not necessary to perform them in this order.

[0050] In the above-described embodiment, EVA is used as an example of the carbonyl group-containing polymer, but other carbonyl group-containing polymers such as those described above may be used instead of EVA, and the same effects as those described above can be obtained in this case as well. [Explanation of symbols]

[0051] 1. Mixing machine 10...Case 3. Calendar molding machine 4. Embossing machine 5. Laminating machine S1, S2, S3, S4...resin sheets R....Resin mixture R1··· resin (waste acrylic resin) R2··· resin (carbonyl group-containing polymer) R3: Plate-shaped waste acrylic resin RS1, RS2, RS4...Resin sheet roll

Claims

1. A resin sheet produced by kneading 10% by weight to less than 40% by weight of an acrylic resin having a degree of polymerization of 1,000 to 20,000 and more than 60% by weight to 90% by weight of a carbonyl group-containing polymer.

2. The resin sheet according to claim 1 , wherein the acrylic resin is waste acrylic resin.

3. The carbonyl group-containing polymer is any one of an ethylene-vinyl acetate copolymer, an ethylene-allyl acetate copolymer, an ethylene-vinyl propionate copolymer, an ethylene-allyl propionate copolymer, an ethylene-methyl methacrylate copolymer, and an ethylene-ethyl methacrylate copolymer. The resin sheet according to claim 1 or 2.

4. 3. The resin sheet according to claim 1, wherein the carbonyl group-containing polymer is a waste sheet formed of an ethylene-vinyl acetate copolymer.

5. a kneading step of kneading 10% by weight to less than 40% by weight of an acrylic resin having a degree of polymerization of 1,000 to 20,000 and more than 60% by weight to 90% by weight of a carbonyl group-containing polymer; a sheet forming step of forming the kneaded material obtained by the kneading step into a sheet shape by at least one of calendaring, laminating, and embossing; A method for producing a resin sheet comprising the steps of:

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