Resin molded body and method for manufacturing the same

Abstract

To provide a resin molded body capable of having various designs.SOLUTION: A resin molded body contains a resin composition in which a melt flow rate (MFR) measured in accordance with JIS K7210-2:2014 under a load of 21.6 kg and at a temperature of 190°C is either immeasurable or is 0 g / 10 min or more and 3 g / 10 min or less. When the resin molded body is cut, different patterns appear depending on the cut location.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin molded article and a method for producing the same. [Background technology]

[0002] BACKGROUND ART A method is known in which a resin molded article having a flowing pattern (marble-like pattern) of different colors is produced by supplying a plurality of types of thermosetting resin compositions having different color tones into a mold and curing the compositions.

[0003] For example, Patent Document 1 describes a method for producing a resin molded product in which a base thermosetting resin composition and a handle thermosetting resin composition, which has been made more viscous by adding a thickener or crosslinking agent, are supplied to a mold, and these compositions are allowed to flow inside the mold, resulting in a flowing pattern. In Patent Document 1, the viscosity of the handle resin composition is set to at least 1.5 times that of the base resin composition, but not more than 300 Pa·s. This prevents the handle resin composition from leaching into the base resin composition, and allows the handle resin composition to flow sufficiently, resulting in a good flowing pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-107585 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, a method is known in which a molded product having a flow pattern is produced by flowing multiple types of resin compositions with different color tones in a mold. Because the resin compositions flow when heated, this method has traditionally only been able to produce resin molded products having a flow pattern, and it has not been possible to produce resin molded products with patterns that are designed as intended.

[0006] The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and has an object to provide a resin molded article that can have various designs, and a method for manufacturing the same. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problems relates to the following resin molded articles [1] to [6]. [1] A resin molded product comprising a resin composition whose melt flow rate (MFR) measured in accordance with JIS K7210-2:2014 at a load of 21.6 kg and a temperature of 190 ° C. is immeasurable or is 0 g / 10 min or more and 3 g / 10 min or less, When the resin molded body is cut, different patterns appear depending on the cut part. Resin molded body. [2] The resin composition is mainly composed of a resin having an intrinsic viscosity of 1 dL / g or more and 50 dL / g or less, measured in accordance with JIS Z8803:2011. [1] The resin molded article according to [1]. [3] The resin composition is mainly composed of ultra-high molecular weight polyethylene, [1] or [2]. [4] Plate or sheet shape; The resin molded article according to any one of [1] to [3]. [5] Cylindrical The resin molded article according to any one of [1] to [3]. [6] A resin molded article produced from the resin molded article according to any one of [1] to [5]. A resin molded body in film form.

[0008] Another aspect of the present invention for solving the above problems relates to the following methods [7] to [9] for producing a resin molded article. [7] A step of preparing color-tone crushed pieces of a resin composition whose melt flow rate (MFR) measured in accordance with JIS K7210-2:2014 at a load of 21.6 kg and a temperature of 190 ° C. is immeasurable or is 0 g / 10 min or more and 3 g / 10 min or less; A step of placing the crushed pieces inside a mold so that they include areas of different color tones; and a step of molding the crushed pieces placed inside the mold by heating and pressurizing them. A method for manufacturing a resin molded product. [8] The molded product obtained by molding is cut to a predetermined thickness to obtain a sheet-like molded product. [7] A method for producing a resin molded article according to [7]. [9] In the molding step, a cylindrical molded body is molded, The molded body obtained by molding is subjected to skive processing to obtain a film-like molded body. [7] A method for producing a resin molded article according to [7]. [Effects of the Invention]

[0009] According to the present invention, a resin molded article that can have a variety of designs and a method for producing the same are provided. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic perspective view of a resin molded body according to one embodiment of the present invention. [Figure 2] Figure 2A is an example of the surface (cut surface) pattern that appears when a plate-shaped resin molded body is cut at a certain position in the thickness direction, and Figure 2B is an example of the surface (cut surface) pattern that appears when the same resin molded body is cut at a different position in the thickness direction. [Figure 3] FIG. 3 is a schematic diagram showing the arrangement of crushed pieces inside the formwork. [Figure 4] FIG. 4 is a schematic diagram showing how the crushed pieces are heated and pressurized. [Figure 5] FIG. 5A is a schematic perspective view of a resin molded body according to another embodiment of the present invention, as viewed from the front side, and FIG. 5B is a schematic perspective view of the resin molded body as viewed from the back side. [Figure 6] FIG. 6 is a schematic perspective view of a resin molded body according to another embodiment of the present invention, viewed from the front surface side. [Figure 7]7A and 7B are schematic diagrams showing a method for producing a resin molded body. Fig. 7A is a schematic diagram showing a cylindrical molded body produced when producing the resin molded body shown in Fig. 6, and Fig. 7B is a schematic diagram showing how the cylindrical molded body shown in Fig. 7A is skived to cut a film-like molded body from the surface of the molded body. [Figure 8] FIG. 8 is a photograph of the resin molded article produced in the example. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. First embodiment 1-1. Resin molding Fig. 1 is a schematic perspective view of a resin molded body according to one embodiment of the present invention. The resin molded body 100 is a plate-shaped molded body integrally molded from a resin composition containing a resin and a colorant, and has a pattern formed on its surface consisting of multiple regions 100a, 100b, 100c, etc., with different color tones. The resin molded body 100 shown in Fig. 1 is a molded body having a camouflage pattern.

[0012] Each of the regions 100a, 100b, 100c, etc. is formed from a resin composition that has low fluidity when heated and melted. Although each region may be formed from a resin composition containing a different type of resin, it is preferable that each region is formed from a resin composition containing the same type of resin.

[0013] Specifically, each of the regions 100a, 100b, 100c, etc. is formed from a resin composition whose melt flow rate (MFR), measured in accordance with JIS K7210-2:2014 under a load of 21.6 kg and a temperature of 190°C, is either non-flowable and unmeasurable, or is 0 g / 10 min or more and 3 g / 10 min or less. If such a resin composition with low fluidity when heated and melted is used, the resin composition will not flow easily during molding. As a result, in the formed resin molded product 100, each of the regions 100a, 100b, 100c, etc. is molded while maintaining the shape it had when placed in the mold prior to molding.

[0014] In conventional resin molded products such as those described in Patent Document 1, the respective resin compositions flow when heated during molding. As a result, the formed resin molded product has a flow pattern caused by the flow. In contrast, the resin molded product 100 of this embodiment suppresses the flow of the resin composition during molding. As a result, the resin molded product 100 can have various patterns other than the flow pattern.

[0015] Each resin composition contains a resin and a colorant. The resin preferably contains a resin with low fluidity when heated and melted. Specifically, the resin preferably contains ultra-high molecular weight polyethylene (UHMW-PE). By containing UHMW-PE as a main component, the fluidity of the resin composition when heated and melted can be reduced, thereby suppressing the flow of the resin composition during molding. In this specification, "containing as a main component" means that the content of UHMW-PE is 50% by mass or more of the total mass of the resin composition. The content of these resins is preferably 70% by mass or more, and more preferably 90% by mass or more, of the total mass of the resin composition.

[0016] From the viewpoint of suppressing fluidity during heating and melting, the resin preferably has an intrinsic viscosity measured in accordance with JIS Z8803:2011 of 1 dL / g or more and 50 dL / g or less, and more preferably 5 dL / g or more and 35 dL / g or less.

[0017] Ultra-high molecular weight polyethylene has a weight average molecular weight of 100 x 10 4 Over 1000 x 10 4The following polyethylenes can be used. The ultra-high molecular weight polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and another α-olefin. Examples of the other α-olefin include α-olefins having 3 to 20 carbon atoms, such as propylene and 1-butene. When the copolymer is a copolymer, the proportion of ethylene is preferably 80 mol% or more but less than 100 mol%, more preferably 90 mol% or more but less than 100 mol%, and even more preferably 95 mol% or more but less than 100 mol%, based on the total structural units of the copolymer. Furthermore, the ultra-high molecular weight polyethylene may be modified with acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, Nadic Acid (registered trademark), or the like.

[0018] The coloring material may be a dye or a pigment, but a pigment is preferred from the viewpoint of suppressing deterioration during heating. A pigment can be used depending on the color tone exhibited by each region. From the viewpoint of suppressing deterioration of the pigment during heating, the melting point of the resin containing the main component is preferably 100°C or higher and 250°C or lower, and more preferably 110°C or higher and 200°C or lower.

[0019] The resin composition may contain other additives such as a heat stabilizer, a light stabilizer, an antioxidant, a plasticizer, a lubricant, a flame retardant, an ultraviolet absorber, an antistatic agent, an antifungal agent, and a conductive filler.

[0020] As will be described later, the resin molded body 100 can be manufactured by placing crushed pieces of a plurality of resin compositions having different color tones in a mold and applying heat and pressure. Depending on the arrangement of the crushed pieces, when the resin molded body 100 is cut at different positions, a pattern with a different arrangement of a plurality of regions with different color tones appears at each cut site.

[0021] Fig. 2A shows an example of a surface (cut surface) pattern that appears when a plate-shaped resin molded product 100 having a camouflage pattern as shown in Fig. 1 is cut at a certain position in the thickness direction. Fig. 2B shows an example of a surface (cut surface) pattern that appears when the same resin molded product 100 is cut at a different position in the thickness direction. When such a resin molded product 100 is processed by cutting or the like, various patterns can appear on each cut surface.

[0022] 1-2. Manufacturing method of resin molded body The resin molded body 100 is crushed pieces of the resin composition described above, and can be manufactured by preparing crushed pieces having a color tone, placing the crushed pieces having the color tone inside a mold, and molding the crushed pieces placed inside the mold by heating and pressurizing them.

[0023] 1-2-1. Preparation process The crushed pieces are small pieces obtained by crushing the resin composition described above, i.e., a resin composition whose melt flow rate (MFR) measured in accordance with JIS K7210-2:2014 under a load of 21.6 kg and at a temperature of 190°C is either non-flowable and unmeasurable or is 0 g / 10 min to 3 g / 10 min. The crushed pieces can be obtained, for example, by crushing or pulverizing recycled waste materials or defective products generated during manufacturing. To promote the cyclical use of resin materials, it is preferable to use recycled waste materials or defective products generated during manufacturing. Such waste materials and defective products inherently have a color tone appropriate for their intended use. Therefore, color adjustment is not required to produce the resin molded product 100.

[0024] The shape of the crushed pieces is not particularly limited. Crushed pieces having a shape corresponding to the pattern of the resin molded product 100 to be manufactured may be prepared. For example, the size of each crushed piece is preferably 0.5 mm or more and 200 mm or less in diameter (longer diameter in the case of non-spherical pieces), more preferably 1 mm or more and 100 mm or less, and even more preferably 2 mm or more and 50 mm or less. The smaller the size of the crushed pieces, the more complex the pattern that can be formed.

[0025] Furthermore, the planar shape of each crushed piece is not particularly limited, and can be a square, rectangle, parallelogram, trapezoid and other quadrangular shapes, equilateral triangle and other triangular shapes, other polygonal shapes, circle and ellipse, and any other shape.

[0026] In this case, it is preferable to prepare crushed pieces of a plurality of different colors. The crushed pieces may be of a single color, or may have patterns of different colors formed therein. When crushed pieces having a pattern are used, the pattern is reflected on the surface or inside of the resin molded product to be formed.

[0027] In this case, virgin material of the above-mentioned resin may be prepared in addition to the crushed pieces. Virgin material is particles obtained by polymerizing the above-mentioned resin by suspension polymerization or the like. The particle size of the virgin material particles may be 5 μm or more and 300 μm or less. By preparing virgin material and crushed pieces of a single color tone, a molded product can be produced on which a pattern is formed by the color tone of the virgin material and the color tone of the crushed pieces. Alternatively, virgin material and crushed pieces of multiple colors with different color tones may be prepared to produce a molded product on which a pattern of multiple colors is formed.

[0028] When crushed pieces and virgin material are used in combination, the ratio between them is not limited and can be any ratio.

[0029] 1-2-2. Process of placing inside the mold Next, the prepared crushed pieces are placed inside a mold. For example, the crushed pieces may be placed tightly inside a press molding frame. When crushed pieces and virgin material particles are used together, the crushed pieces and particles are placed inside the mold.

[0030] Fig. 3 is a schematic diagram showing the arrangement of crushed pieces 220 inside a mold 210. As shown in Fig. 3, in this process, crushed pieces 220 (and optionally particles of virgin material) are arranged without gaps inside the mold 210. At this time, when it is desired to form a predetermined pattern on the surface or inside of the resin molded body 100, crushed pieces 220 of a color tone corresponding to the pattern are arranged in positions corresponding to the pattern.

[0031] 1-2-3. Molding process Next, the crushed pieces 220 (and any virgin material particles placed inside the mold) are heated and pressurized to melt and weld the resin composition, thereby obtaining the resin molded body 100 in which the crushed pieces 220 (and virgin material particles) are welded together and molded integrally.

[0032] FIG. 4 is a schematic diagram showing the process of heating and pressurizing the crushed pieces 220. As shown in FIG. 4, by heating and pressing a lower mold 230 and an upper mold 240 holding a mold frame 210 of a press molding machine together, the crushed pieces 220 arranged inside the mold frame 210 can be welded together and integrated. The heating temperature may be a temperature at which the resin, which is the main component of the resin composition, melts, and can be 130°C or higher and 230°C or lower. The pressure during the pressing can be 0.5 MPa or higher and 10 MPa or lower. However, the heating and pressurizing method is not limited to press molding using a press molding machine. Other methods of heating and pressurizing include press molding using a double-belt press and autoclave molding using an autoclave device.

[0033] Thereafter, the molded resin body 100 is sufficiently cooled and then removed to obtain the molded resin body 100. The molded resin body 100 thus obtained may be cut into a desired shape. For example, it may be cut into a sheet having a thickness of 1 mm to 5 mm, a width of 1000 mm or less, and a length of 2000 mm or less.

[0034] The resin molded body 100 obtained in this manner has a pattern on its surface consisting of an arrangement of multiple regions 100a, 100b, 100c, etc., which originate from the broken pieces 220. The resin molded body 100 also has a pattern inside it which originates from the broken pieces 220. Therefore, when the resin molded body 100 is cut, different patterns appear depending on the cut area.

[0035] The resin molded product 100 described above is integrally molded by press molding, but by suppressing the flow of the resin composition during molding, it is possible to form a wide variety of patterns other than flow patterns. Furthermore, by suppressing the flow of the resin composition during molding, it is possible to form an intended pattern and obtain a resin molded product having an intended design.

[0036] In addition, since the above-described resin molded body 100 has a pattern formed by regions having different colors inside the molded body, the pattern appears on the processed surface even when it is cut or processed into a shape according to the intended use. Furthermore, since the above-described resin molded body 100 has a pattern formed by regions having different colors inside the molded body, the pattern will not disappear even if the surface is worn or the like.

[0037] Furthermore, when the resin molded body 100 is produced from a resin composition containing ultra-high molecular weight polyethylene as a main component, the resin molded body can be endowed with the low friction and abrasion resistance that are characteristic of ultra-high molecular weight polyethylene.

[0038] 2. Second embodiment FIG. 5A is a schematic perspective view of a resin molded body according to another embodiment of the present invention, as viewed from the front side, and FIG. 5B is a schematic perspective view of the resin molded body as viewed from the back side.

[0039] The resin molded body 500 is a plate-like integrally molded body with different designs on the front and back sides. Specifically, the resin molded body 500 is a plate-like molded body integrally molded from a resin composition containing a resin and a coloring material, with the front side having a green background with black stripes and the back side having a red background with small black dots scattered thereon. This gives the resin molded body 500 an overall watermelon design.

[0040] In this way, by suppressing the flow of the resin composition while producing a resin molded body, it is possible to suppress mixing of the resin composition between the front and back sides, and to produce a resin molded body with completely different patterns on the front and back sides.

[0041] 3. Third embodiment FIG. 6 is a schematic perspective view of a resin molded body according to another embodiment of the present invention, viewed from the front surface side.

[0042] The resin molded body 600 is a film-like molded body, and a pattern consisting of multiple areas with different color tones is formed on the surface. The resin molded body 600 shown in Figure 6 is a molded body with a camouflage pattern.

[0043] The resin molded body may have a thickness of, for example, 0.05 mm or more and 0.5 mm or less, a width of 300 mm or more and 400 mm or less, and a length of 100 m or more and 500 m or less.

[0044] The resin molding 600 can be produced by producing a resin molding having a shape such as a plate or a cylinder using the method described above, then cutting it from the front (or back) to a predetermined thickness and cutting it into a film.

[0045] 7A and 7B are schematic diagrams showing a method for producing a resin molded body 600. First, a cylindrical molded body 700 is produced as shown in FIG. 7A by heating and pressurizing the crushed pieces described above. Next, as shown in FIG. 7B, the molded body 700 is skived, and a film-like resin molded body 600 is cut from the surface of the molded body 700. In this manner, a film-like resin molded body 600 having a predetermined pattern is obtained. The molded body 700 is a resin molded body in which different patterns appear depending on the cut location. Therefore, as cutting of the molded body 700 progresses, the surface pattern of the film-like resin molded body 600 produced can be changed.

[0046] The resin molded body 600 may have an adhesive layer on the back side thereof, and may further have a release layer to prevent the adhesive layer from sticking during storage.

[0047] 4. Other embodiments The above-described embodiments are examples of the present invention, and the present invention is not limited to the above-described embodiments. It goes without saying that various other embodiments are possible within the scope of the concept of the present invention.

[0048] For example, the pattern formed on the surface and inside of the resin molded body is not particularly limited, and may be any pattern such as letters, pictures, various patterns such as lattice patterns, etc.

[0049] The shape of the resin molded body is not particularly limited, and may be a polygonal pillar, a cylinder, a polygonal pyramid, a cone, or any other shape suited to various uses.

[0050] The resin molded article described above can be used for a wide variety of purposes, such as furniture, toys, slides, mouse pads, mouse bodies, and the like. [Example]

[0051] The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0052] A resin molded product containing ultra-high molecular weight polyethylene with a melt flow rate (MFR) of less than 0.1 g / 10 min, measured at a load of 21.6 kg and a temperature of 190°C in accordance with JIS K7210-2:2014, was crushed. The crushed resin molded product was recovered through recycling, and crushing yielded crushed pieces with multiple different color tones.

[0053] The crushed pieces obtained by crushing were filled into a mold measuring 125 mm × 125 mm × 20 mm, and heated and pressed at a temperature of 190°C and a pressure of 8 MPa. In this way, a resin molded product with a clear pattern, as shown in Figure 8, was produced. [Industrial Applicability]

[0054] The resin molded article according to the present invention has high designability, and is therefore expected to be used in a variety of applications that require designability, as well as in a variety of applications that did not previously require designability but where improved designability will increase the appeal of the product. [Explanation of symbols]

[0055] 100, 500, 600 Resin molding 100a, 100b, 100c area 210 Formwork 220 debris 230 Lower mold 240 Upper mold 700 Molded body

Claims

1. A resin molded product comprising a resin composition whose melt flow rate (MFR), measured in accordance with JIS K7210-2:2014 at a load of 21.6 kg and a temperature of 190°C, is immeasurable or is 0 g / 10 min or more and 3 g / 10 min or less, When the resin molded body is cut, different patterns appear depending on the cut part. Resin molded body.

2. The resin composition contains, as a main component, a resin having an intrinsic viscosity measured in accordance with JIS Z8803:2011 of 1 dL / g or more and 50 dL / g or less. The resin molded article according to claim 1.

3. The resin composition contains ultra-high molecular weight polyethylene as a main component, The resin molded article according to claim 1.

4. Plate-like or sea-like, The resin molded article according to any one of claims 1 to 3.

5. It is cylindrical, The resin molded article according to any one of claims 1 to 3.

6. Produced from the resin molded article according to claim 5. A resin molded body in film form.

7. A step of preparing crushed pieces of a resin composition having a color tone, the melt flow rate (MFR) of which, measured in accordance with JIS K7210-2:2014 at a load of 21.6 kg and a temperature of 190°C, is immeasurable or is 0 g / 10 min or more and 3 g / 10 min or less; A step of placing the crushed pieces inside a mold so that they include areas of different color tones; and a step of molding the crushed pieces placed inside the mold by heating and pressurizing them. A method for manufacturing a resin molded product.

8. The molded body obtained by molding is cut to a predetermined thickness to obtain a sheet-like molded body. The method for producing the resin molded article according to claim 7 .

9. In the molding step, a cylindrical molded body is molded, The molded body obtained by molding is subjected to skive processing to obtain a film-like molded body. The method for producing the resin molded article according to claim 7 .

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