Method for producing additive for resin molded article

Abstract

To provide a technology for enhancing functionality of a resin molded article.SOLUTION: A method for producing an additive for a resin molded article, the method including utilizing a supercritical fluid to obtain, from a raw material additive insoluble in the supercritical fluid, an additive having a smaller average particle diameter than the raw material additive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing an additive for a resin molded product. [Background technology]

[0002] Molded articles made of resin are used in a variety of fields. For example, laminated films made of multiple resin layers can exhibit performance and functions that cannot be achieved by single-layer films, and are therefore used in a wide range of fields, including decorative sheets, packaging materials, and electronic components.

[0003] Decorative sheets are used, for example, as building materials for the interior and exterior decoration of buildings, or as surface materials for fixtures or home appliances. Decorative sheets are used as decorative panels by being attached to substrates such as wood boards, inorganic boards, and metal plates.

[0004] Decorative sheets generally use polyvinyl chloride, as described in Patent Document 1. However, such decorative sheets generate toxic gases when burned. For this reason, many decorative sheets have been proposed that use polyolefin resins instead of polyvinyl chloride, as described in Patent Documents 2 to 4.

[0005] Decorative sheets that use polyolefin resins instead of polyvinyl chloride do not emit chlorine-derived toxic gases when burned. However, because these decorative sheets use general polypropylene sheets or soft polypropylene sheets, they have far inferior scratch resistance compared to decorative sheets that use polyvinyl chloride.

[0006] The use of highly crystalline polypropylene, which has a high initial bending modulus, as the polyolefin resin can achieve excellent abrasion resistance. However, decorative sheets using such highly crystalline polypropylene can sometimes break or crack around the periphery when subjected to bending processes such as V-groove bending.

[0007] Furthermore, polypropylene resins are usually milky white because their spherulite size is larger than the wavelength of visible light (400 to 750 nm). In decorative sheets, the transparent resin layer is required to protect the underlying pattern layer and base sheet, while not interfering with the visibility of the patterns and designs printed thereon from the outermost surface of the decorative sheet.

[0008] To address these issues, Patent Document 5 describes the encapsulation of a nucleating agent in an outer membrane made of phospholipids by supercritical reverse-phase evaporation, and the addition of the resulting vesicles to a crystalline polypropylene resin. The vesicles obtained by supercritical reverse-phase evaporation are extremely small in size. Therefore, adding these vesicles to a crystalline polypropylene resin can significantly reduce the size of the spherulites and dramatically improve the crystallinity of the crystalline portion. As a result, high transparency can be achieved, as well as excellent scratch resistance and post-processing resistance.

[0009] The nano-processing of nucleating agents using the supercritical reverse-phase evaporation method described above involves injecting an aqueous phase into a mixture of supercritical carbon dioxide, an organic solvent, a phospholipid, and a nucleating agent, followed by vigorous stirring to generate an emulsion of supercritical carbon dioxide and an aqueous phase. The carbon dioxide then expands and evaporates under reduced pressure, resulting in phase inversion, producing vesicles consisting of nanocapsules in which the phospholipid covers the surface of the nucleating agent with a monolayer membrane. In this nano-processing, there is concern about vesicle size variation depending on the degree of stirring and mixing. Furthermore, from the perspective of production cost, it is desirable to reduce the number of steps and enable production using a simple manufacturing method. Furthermore, resin molded products generally suffer from the problem of bleed-out, in which incorporated additives and residual solvents rise to the surface over time. Therefore, it is preferable to reduce the types and amounts of these additives and organic solvents used. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2-128843 [Patent Document 2] Japanese Patent Application Publication No. 5-278137 [Patent Document 3] Japanese Patent Application Publication No. 6-198831 [Patent Document 4] Japanese Patent Application Publication No. 9-328562 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-168830 Summary of the Invention [Problem to be solved by the invention]

[0011] Various additives are used in various resin molded products, such as stabilizers to prevent deterioration due to heat, light, oxidation, etc. during or after molding processing, modifiers to impart strength, transparency, color tone, etc., and nucleating agents. If the functions of the various additives used in these resin molded products can be maximized, the functionality of the resin molded products can be significantly improved.

[0012] An object of the present invention is to provide a technique for improving the functionality of a resin molded product. [Means for solving the problem]

[0013] According to one aspect of the present invention, there is provided a method for producing an additive for a resin molded product, the method comprising: utilizing a supercritical fluid to obtain, from a raw material additive that is insoluble in the supercritical fluid, an additive having a smaller average particle size than the raw material additive.

[0014] According to another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to the above aspect, which comprises stirring a fluid containing the supercritical fluid and the raw material additive to obtain the additive having a smaller average particle size than the raw material additive.

[0015] According to yet another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to the above aspect, comprising mixing the supercritical fluid with a solution containing the raw material additive and a solvent capable of dissolving the raw material additive, thereby precipitating the additive having a smaller average particle size than the raw material additive.

[0016] According to yet another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to the above aspect, comprising melting the raw material additive in the supercritical fluid, and reducing the pressure of a fluid containing the melted raw material additive and the supercritical fluid, thereby precipitating the additive having a smaller average particle size than the raw material additive.

[0017] According to yet another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to any of the above aspects, in which the raw material additive has an average particle size of 4 μm or more, and the additive having a smaller average particle size than the raw material additive has an average particle size of 5000 nm or less. According to yet another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to any of the above aspects, in which the raw material additive has an average particle size of 5 μm or more, and the additive having a smaller average particle size than the raw material additive has an average particle size of 4,500 nm or less.

[0018] According to yet another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to any one of the above aspects, wherein the additive is a nucleating agent.

[0019] According to yet another aspect of the present invention, there is provided a method for producing an additive for a resin molded product according to any one of the above aspects, wherein the additive is a plastic decomposition inhibitor.

[0020] According to yet another aspect of the present invention, there is provided the method for producing an additive for a resin molded product according to any one of the above aspects, wherein the supercritical fluid comprises carbon dioxide.

[0021] According to yet another aspect of the present invention, there is provided a method for producing a masterbatch, the method including producing an additive for a resin molded product by the method for producing the additive according to any one of the above aspects, and kneading a raw material containing a first raw material resin and the additive.

[0022] According to yet another aspect of the present invention, there is provided a method for producing a masterbatch according to the above aspect, which comprises kneading the raw materials in the presence of a supercritical fluid.

[0023] According to yet another aspect of the present invention, there is provided a method for producing a masterbatch according to any of the above aspects, wherein the first raw material resin is a resin in which the proportion of polyolefin resin is in the range of 90 to 100 mass %.

[0024] According to yet another aspect of the present invention, there is provided a method for producing a resin, the method including producing a masterbatch by the method for producing a masterbatch according to any of the above aspects, and kneading a raw material including the masterbatch and a second raw material resin.

[0025] According to yet another aspect of the present invention, there is provided a method for producing a resin according to the above aspect, wherein the first raw resin and the second raw resin are each independently a resin having a polyolefin resin content in the range of 90 to 100 mass %.

[0026] According to yet another aspect of the present invention, there is provided a method for manufacturing a resin molded product, the method including manufacturing the resin by the resin manufacturing method according to the above aspect, and molding the resin to manufacture a resin molded product.

[0027] According to yet another aspect of the present invention, there is provided the method for producing a resin molded article according to the above aspect, wherein the concentration of the additive in the resin molded article is within a range of 0.005 to 1.0 mass %.

[0028] According to yet another aspect of the present invention, there is provided a method for producing a resin molded article according to any one of the above aspects, wherein the resin molded article is a resin layer.

[0029] According to yet another aspect of the present invention, a resin molded article is manufactured by forming the resin layer by the method for manufacturing a resin molded article according to any one of the above aspects, and laminating one or more other layers on the resin layer. A method for manufacturing a laminate comprising:

[0030] According to yet another aspect of the present invention, there is provided a method for producing a laminate according to the above aspect, wherein the laminate is a decorative sheet.

[0031] According to yet another aspect of the present invention, there is provided an additive for resin molding obtained by the method for producing an additive for resin molded products according to any one of the above aspects.

[0032] According to yet another aspect of the present invention, there is provided a masterbatch obtained by the method for producing a masterbatch according to any of the above aspects.

[0033] According to yet another aspect of the present invention, there is provided a resin molded product obtained by the method for producing a resin molded product according to any one of the above aspects.

[0034] According to yet another aspect of the present invention, there is provided a resin layer obtained by the method for producing a resin molded article according to any one of the above aspects.

[0035] According to yet another aspect of the present invention, there is provided a laminate obtained by the method for producing a laminate according to any of the above aspects.

[0036] According to yet another aspect of the present invention, there is provided a laminate according to the above aspect which is a decorative sheet. [Effects of the Invention]

[0037] The present invention provides a technique for improving the functionality of a resin molded product. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a cross-sectional view of a decorative material including a decorative sheet according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] The following describes embodiments of the present invention. The embodiments described below are more specific embodiments of any of the above aspects. The following features can be incorporated into each of the above aspects, either singly or in combination.

[0040] Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited by the materials, shapes, structures, etc. of the components described below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims.

[0041] It should be noted that the drawings referred to below are schematic, and the relationship between dimensions in one direction and dimensions in another direction, and the relationship between the dimensions of one component and the dimensions of another component, etc. may differ from the actual figures.

[0042] <1> Additives for resin moldings A method for producing an additive for a molded resin article includes utilizing a supercritical fluid to obtain, from a raw additive that is insoluble in the supercritical fluid, an additive having a smaller average particle size compared to the raw additive.

[0043] A wide variety of additives are used in resin molded products, including those that improve the physical properties of resins and those that impart properties that resins do not inherently possess. The above method can be applied to the microparticulation treatment of various additives added to resins. Examples of additives include nucleating agents, plastic degradation inhibitors, plasticizers, flame retardants, antistatic agents, colorants, lubricants, reinforcing agents, antifogging agents, and antibacterial agents.

[0044] Nucleating agents either promote the formation of crystal nuclei during resin crystallization or act as crystal nuclei themselves. Examples of nucleating agents include fatty acid metal salts, rosin metal salt-based nucleating agents, talc, sorbitol-based nucleating agents, nonitol-based nucleating agents, amide-based nucleating agents, phosphate ester metal salts, and aromatic carboxylic acid metal salts.

[0045] A plastic decomposition inhibitor is a stabilizer that prevents deterioration of a resin molded product due to heat, light, oxidation, etc. during or after molding processing. Examples of plastic decomposition inhibitors include antioxidants, light stabilizers, and heat stabilizers.

[0046] Examples of antioxidants include phenol-based antioxidants, thioether-based antioxidants, and phosphorus-based antioxidants. Examples of light stabilizers include hindered amine-based light stabilizers, benzotriazole-based light stabilizers, and triazine-based light stabilizers. Examples of heat stabilizers include metal soaps, organotin-based stabilizers, and lead-based stabilizers.

[0047] The raw material additive used in this method is a raw material additive that is insoluble in the supercritical fluid. The supercritical fluid can be, for example, carbon dioxide or nitrogen. The supercritical fluid is preferably carbon dioxide. Whether a raw material additive is a raw material additive that is insoluble in a supercritical fluid can be determined as follows: 50 mg of the raw material additive is preliminarily added to a pressure vessel with a capacity of 5 mL. A supercritical fluid is then injected into the vessel so that the temperature is 40°C and the pressure is 20 MPa, and the vessel is maintained at this temperature and pressure for 10 minutes. The pressure vessel is then opened, and the mass of the remaining raw material additive is measured. If the mass of the remaining raw material additive is greater than 40 mg, the raw material additive can be determined to be a "raw material additive that is insoluble in a supercritical fluid."

[0048] The average particle size of the raw additive is, for example, 0.5 μm or more, preferably 1 μm or more, more preferably 4 μm or more, and even more preferably 5 μm or more. The average particle size of the raw additive is preferably within the range of 0.5 to 20,000 μm, more preferably within the range of 1 to 10,000 μm, even more preferably within the range of 4 to 10,000 μm, and even more preferably within the range of 5 to 10,000 μm. The above method can produce additive fine particles with a smaller average particle size than the raw additive. The additive fine particles can have an average particle size of, for example, 5,000 nm or less, preferably 4,500 nm or less. The additive fine particles preferably have an average particle size within the range of 10 to 5,000 nm, and more preferably have an average particle size within the range of 10 to 4,500 nm. In this specification, "particle size" refers to the length of the long side of the smallest rectangle circumscribing a particle present in a particle image observed by an electron microscope, and "average particle size" refers to the average particle size of multiple particles.

[0049] Using the above method, one type of raw material additive may be treated with a supercritical fluid, or two or more (multiple types) raw material additives may be treated with a supercritical fluid. Treating two or more (multiple types) raw material additives with a supercritical fluid to obtain multiple types of additive microparticles and using the resulting multiple types of additive microparticles in a resin molded product can improve multiple performances in the resin molded product. When treating two or more (multiple types) raw material additives with a supercritical fluid, the two or more (multiple types) raw material additives may be treated as a mixture with the supercritical fluid simultaneously (i.e., in one pressure vessel), or the two or more (multiple types) raw material additives may be treated individually (i.e., in separate pressure vessels).

[0050] The above method will be described below based on an embodiment. In the following description, the "raw material additive insoluble in a supercritical fluid" is also referred to as the "raw material additive," and the "additive having a smaller average particle size than the raw material additive" obtained by this method is also referred to as the "additive" or "additive fine particles."

[0051] According to one embodiment, the additive fine particles can be obtained by utilizing the diffusivity of a supercritical fluid to reduce the particle size of a raw material additive in the form of an aggregate formed by the aggregation of a large number of primary particles. That is, according to a first embodiment, a method for producing an additive for a resin molded product includes stirring a fluid containing a supercritical fluid and a raw material additive to obtain an additive having a smaller average particle size than the raw material additive.

[0052] According to another embodiment, the additive fine particles can be obtained by precipitating the additive from a solution of the raw material additive using a supercritical fluid as a poor solvent. That is, according to a second embodiment, a method for producing an additive for a resin molded product includes mixing a supercritical fluid with a solution containing the raw material additive and a solvent that dissolves the raw material additive, and precipitating an additive having a smaller average particle size than the raw material additive.

[0053] According to yet another embodiment, the additive microparticles can be obtained by decompressing a fluid containing a melted raw material additive and a supercritical fluid to precipitate the additive microparticles. That is, according to a third embodiment, a method for producing an additive for a resin molded product includes melting a raw material additive in a supercritical fluid, and decompressing a fluid containing the melted raw material additive and a supercritical fluid to precipitate an additive having a smaller average particle size than the raw material additive.

[0054] The method according to the first embodiment, the method according to the second embodiment, and the method according to the third embodiment will be described below in order.

[0055] <1.1> First embodiment In the method according to the first embodiment, fatty acid metal salts, rosin metal salt-based nucleating agents, hindered amine-based light stabilizers, talc, sorbitol-based nucleating agents, phosphate ester metal salts, phenol-based antioxidants, and the like can be used as raw material additives.

[0056] The method according to the first embodiment can be carried out in a production apparatus including, for example, a pressure vessel and a stirring blade installed therein. The production apparatus may further include a temperature control device including at least one of a cooling device and a heating device.

[0057] The additive can be produced using this production apparatus by stirring a fluid containing a supercritical fluid and a raw material additive in a pressure vessel with a stirring blade.

[0058] In this method, the amount of supercritical fluid per 100 parts by weight of raw material additive can be, for example, in the range of 100 to 1,000,000 parts by weight, preferably 200 to 100,000 parts by weight.

[0059] The treatment using a supercritical fluid in a pressure vessel can be carried out under a pressure ranging from, for example, 7.2 to 100 MPa, preferably from 10 to 80 MPa, and at a temperature ranging from, for example, 32 to 250°C, preferably from 35 to 200°C.

[0060] The stirring time can be, for example, within a range of 5 minutes to 24 hours, preferably 10 minutes to 2 hours, and the stirring speed can be, for example, within a range of 100 to 10,000 rpm, preferably 200 to 1,000 rpm.

[0061] As mentioned above, the supercritical fluid is preferably carbon dioxide, which becomes a supercritical fluid under conditions of 31° C. or higher and 7.4 MPa or higher.

[0062] The raw material additive is in the form of an agglomerate formed by the aggregation of a large number of primary particles. A supercritical fluid has a density close to that of a liquid and a diffusion coefficient close to that of a gas. Therefore, in the method according to the first embodiment, the supercritical fluid penetrates into the gaps between the large number of primary particles constituting the agglomerate, separating at least some of the bonded primary particles from each other. As a result, the agglomerate can be broken down into smaller particles, for example, into primary particles.

[0063] In the method according to the first embodiment, an additive that has been reduced to small particles (for example, an additive that has been reduced to primary particles) may be obtained immediately after the treatment using the supercritical fluid. Alternatively, in the method according to the first embodiment, the raw material additive may change to a brittle aggregate state in which the bonds between primary particles are weakened immediately after the treatment using the supercritical fluid, and may change to small particles (for example, primary particles) when an external force is applied in a subsequent step (for example, a kneading step with a raw material resin).

[0064] The method according to the first embodiment can produce additive microparticles having an average particle size smaller than that of the raw additive. The method according to the first embodiment can produce additive microparticles having an average particle size, for example, in the range of 10 to 100,000 nm, preferably 10 to 10,000 nm, and more preferably 10 to 5,000 nm. Furthermore, the method according to the first embodiment can produce additive microparticles having an average particle size, for example, in the range of 1 to 99%, preferably 1 to 90%, of the average particle size of the raw additive.

[0065] <1.2> Second embodiment In the method according to the second embodiment, for example, a rosin metal salt-based nucleating agent, a hindered amine-based light stabilizer, a sorbitol-based nucleating agent, a phosphate ester metal salt, a phenol-based antioxidant, or the like can be used as a raw material additive.

[0066] The method according to the second embodiment can be carried out in a manufacturing apparatus including, for example, a pressure vessel and a supply device that introduces at least one of a supercritical fluid and a solution of a raw material additive into the pressure vessel. In one example, the supply device includes a supercritical fluid supply device that introduces the supercritical fluid into the pressure vessel, and a solution supply device that introduces the solution of the raw material additive into the pressure vessel. This manufacturing apparatus may further include a temperature control device including at least one of a cooling device and a heating device.

[0067] The additive can be produced using this production apparatus by mixing a supercritical fluid with a solution containing a raw material additive and a solvent that dissolves the raw material additive in a pressure vessel, thereby precipitating the additive.

[0068] In this method, first, a solution containing the raw material additive and a solvent for dissolving it (i.e., a raw material additive solution) is prepared. In this solution, it is preferable that all of the raw material additive is dissolved in the solvent. This solution may be prepared in a pressure vessel or in another vessel.

[0069] The solvent for dissolving the raw material additive is not particularly limited as long as it dissolves the raw material additive, and is preferably one that can form a homogeneous phase when mixed with the supercritical fluid. Examples of solvents that can be used for dissolving the raw material additive include hexane, methanol, and ethanol.

[0070] The amount of the solvent relative to 100 parts by mass of the raw material additive can be, for example, within the range of 1 to 100,000 parts by mass, preferably 50 to 10,000 parts by mass.

[0071] In this method, the additive is then produced by the anti-solvent method using the above solution. Specifically, the above solution is mixed with a supercritical fluid in a pressure vessel, and the supercritical fluid is used as an anti-solvent to precipitate the additive from the raw additive solution.

[0072] The supercritical fluid may be mixed with the raw material additive solution by introducing the supercritical fluid into a pressure vessel containing the raw material additive solution. This method is called the GAS method (Gas Anti-Solvent Recrystallization method).

[0073] In this method, the supercritical fluid can be supplied into the pressure vessel so that the pressure inside the pressure vessel increases at a rate of, for example, 0.005 to 15 MPa / sec, preferably 0.01 to 10 MPa / sec. The total amount of supercritical fluid supplied into the pressure vessel can be, for example, 100 to 1,000,000 parts by mass, preferably 200 to 100,000 parts by mass, per 100 parts by mass of raw material additives. The total amount of supercritical fluid supplied into the pressure vessel can be, for example, 0.1 to 1,000,000 parts by mass, preferably 10 to 100,000 parts by mass, per 100 parts by mass of solvent.

[0074] The supercritical fluid can be supplied into the pressure vessel at a temperature ranging from, for example, 32 to 250° C., preferably from 35 to 200° C. The supercritical fluid can be supplied into the pressure vessel for a period of time ranging from 1 to 600 minutes, preferably from 1 to 60 minutes.

[0075] Alternatively, the supercritical fluid and the solution of the raw material additive may be mixed by introducing the solution of the raw material additive into a pressure vessel containing the supercritical fluid, a method known as the SAS (Supercritical Antisolvent Recrystallization) method.

[0076] In this method, the raw material additive solution can be supplied into the pressure vessel at a rate of, for example, 0.01 to 10 mL / min, preferably 0.1 to 5 mL / min, per 500 g of supercritical fluid. Supplying the raw material additive solution into the pressure vessel can be achieved, for example, by spraying the raw material additive solution through a nozzle. The amount of supercritical fluid can be, for example, 100,000 to 10,000,000 parts by mass, preferably 500,000 to 5,000,000 parts by mass, per 100 parts by mass of the total amount of raw material additives. The amount of supercritical fluid can also be, for example, 50 to 1500 parts by mass, preferably 100 to 1000 parts by mass, per 100 parts by mass of the total amount of solvent.

[0077] The feed of the raw material additive solution into the pressure vessel can be carried out under a pressure of, for example, 7.2 to 100 MPa, preferably 10 to 80 MPa. The feed of the raw material additive solution into the pressure vessel can be carried out at a temperature of, for example, 32 to 250° C., preferably 35 to 200° C. The feed of the raw material additive solution into the pressure vessel can be carried out over a period of, for example, 0.1 to 600 minutes, preferably 0.1 to 60 minutes.

[0078] Alternatively, to obtain finer particles, the supercritical fluid and the solution of the raw material additive may be mixed by a method for rapidly mixing the supercritical fluid and the solution. Examples of such a method include the SAS-CTAR (Supercritical Precipitation in the Concentric Tube Antisolvent Reactor) method, in which a continuous operation of simultaneously introducing a supercritical fluid and a solution is performed in a concentric tube, the SAS-MD (SAS using Micro Device) method, in which a microdevice is used in the mixing section where the supercritical fluid and the solution are mixed, and the SEDS (Solution-Enhanced Dispersion of Solid) method, in which a coaxial nozzle is used to mix the supercritical fluid and the solution at the outlet of the coaxial nozzle.

[0079] Because supercritical fluids have a higher diffusion rate than liquids, the method according to the second embodiment allows the supercritical fluid to diffuse at a high diffusion rate, resulting in a phase transition in a short time. Therefore, the method according to the second embodiment makes it possible to produce fine particles with a small particle size. The method according to the second embodiment can produce fine additive particles with an average particle size in the range of, for example, 10 to 2500 nm, preferably 10 to 2000 nm. Furthermore, the method according to the second embodiment can produce fine additive particles with an average particle size in the range of, for example, 1 to 99%, preferably 1 to 80%, of the average particle size of the raw additive.

[0080] <1.3> Third embodiment In the method according to the third embodiment, examples of raw material additives that can be used include fatty acid metal salts, rosin metal salt-based nucleating agents, hindered amine-based light stabilizers, sorbitol-based nucleating agents, phosphate ester metal salts, and phenol-based antioxidants.

[0081] The method according to the third embodiment can be carried out, for example, in a manufacturing apparatus equipped with a pressure vessel and a temperature control device including at least one of a cooling device and a heating device.

[0082] The additive can be produced using this production apparatus by melting a raw material additive in a supercritical fluid in a pressure vessel, and reducing the pressure of a fluid containing the melted raw material additive and the supercritical fluid to precipitate the additive.

[0083] In this method, the raw additive is first melted in a supercritical fluid. The melting can be carried out by placing the raw additive in the supercritical fluid under pressure conditions of, for example, 7.2 to 100 MPa, preferably 10 to 80 MPa. The amount of supercritical fluid per 100 parts by mass of the raw additive can be, for example, 0.1 to 1,000,000 parts by mass, preferably 0.1 to 500,000 parts by mass. This melting step can be carried out at a temperature equal to or higher than the melting point of the raw additive under atmospheric pressure conditions, or at a temperature lower than the melting point of the raw additive under atmospheric pressure conditions. For example, when carbon dioxide is used as the supercritical fluid and Chimassorb® 2020 (manufactured by BASF) (melting point 150°C) is used as the raw additive, the temperature in the melting step can be, for example, 50 to 200°C, preferably 50 to 150°C. This results in a high-pressure fluid containing the melted raw additive and the supercritical fluid.

[0084] The high-pressure fluid containing the molten raw material additive and the supercritical fluid is then depressurized. The depressurization can be achieved, for example, by spraying the high-pressure fluid through a nozzle at atmospheric pressure. This method is called the Particles from Gas Saturated Solutions (PGSS) method. In the PGSS method, solid raw material additives are heated in a supercritical fluid to a temperature above their melting point. The molten raw material additives then become dispersed particles in the supercritical fluid or dissolve in the supercritical fluid. When such a high-pressure fluid is sprayed at atmospheric pressure and rapidly expanded to near atmospheric pressure, the supercritical fluid rapidly expands due to the sudden depressurization and temperature drop. The rapid expansion of the supercritical fluid generates very fine droplets due to a physical explosion effect, and these droplets rapidly dry to obtain fine particles.

[0085] Therefore, the method according to the third embodiment makes it possible to produce fine particles with a small particle size. The method according to the third embodiment makes it possible to obtain fine additive particles having an average particle size in the range of, for example, 10 to 2000 nm, preferably 10 to 1500 nm. Furthermore, the method according to the third embodiment makes it possible to obtain fine additive particles having an average particle size in the range of, for example, 1 to 99%, preferably 1 to 80%, of the average particle size of the raw additive.

[0086] The method according to the third embodiment can be used even if the raw material additive is insoluble in neither the supercritical fluid nor the solvent, as long as the raw material additive melts in the supercritical fluid. In this method, the supercritical fluid diffuses and impregnates the interior of the molecular chain of the raw material additive, thereby lowering the melting point of the raw material additive below that of the raw material additive present under atmospheric pressure conditions. Therefore, this method can also be carried out at a temperature lower than the melting point of the raw material additive present under atmospheric pressure conditions.

[0087] <1.4> Effects Conventionally, it has been difficult to microparticulate raw material additives that are insoluble in supercritical fluids compared to raw material additives that are soluble in supercritical fluids. However, the method described herein makes it possible to microparticulate such raw material additives, and can expand the types of raw material additives that can be microparticulated.

[0088] The additive fine particles obtained by the method described herein have small particle size variations and can be distributed in the resin with high dispersity, so that even a small amount added to the resin can achieve the significant effects required of the additive.

[0089] For example, by producing a microparticulated nucleating agent according to the method described herein and adding it to a transparent resin layer, it is possible to improve the transparency of the transparent resin layer and achieve both high levels of post-processing resistance and scratch resistance.Furthermore, by producing a microparticulated light stabilizer according to the method described herein and adding it to a transparent resin layer, it is possible to improve the weather resistance of the transparent resin layer.

[0090] Bleeding out due to additives in resin molded products is a phenomenon in which the additives aggregate and become coarse over time, eventually precipitating on the surface of the resin molded product. Therefore, by using this method to finely atomize the coarse particles, we can obtain fine particles of additives with small particle size variation, and use these as additives for resin molded products, thereby making it possible to suppress bleed-out.

[0091] Furthermore, as described above, the additive obtained by this method exerts a significant effect even in a small amount, so that the amount used can be reduced, and therefore bleeding out due to a high concentration of the additive can be prevented.

[0092] In particular, the method according to the first embodiment reduces the particle size of a raw material additive in the form of an aggregate formed by the aggregation of a large number of primary particles, and therefore can microparticulate the raw material additive without changing its crystal structure. In particular, the methods according to the second and third embodiments dissolve or melt the raw material additive and then precipitate the additive, making it possible to produce microparticles with a smaller particle size.

[0093] Furthermore, when multiple raw material additives are treated simultaneously (i.e., in a single pressure vessel) with a supercritical fluid as a mixture by the method described herein, the multiple raw material additives are mixed in the supercritical fluid. Therefore, in this case, multiple types of additive microparticles can be obtained in a more uniformly mixed state compared to when multiple raw material additives are treated individually (i.e., in separate pressure vessels) with a supercritical fluid. When the additive microparticles obtained in this manner are kneaded with a resin to produce a masterbatch or a resin molded product, the masterbatch or resin molded product can be produced with multiple types of additive microparticles more uniformly dispersed. When multiple products are produced using such masterbatches or resin molded products, the multiple types of additive microparticles are more uniformly dispersed, so the functions of each additive are more stably exhibited in all products, and product variation can be reduced. Furthermore, when a resin layer is produced as a resin molded product, the multiple types of additive microparticles are more uniformly dispersed in the in-plane direction of the resin layer, so the functions of each additive can be more uniformly exhibited in the in-plane direction of the resin layer.

[0094] Furthermore, when multiple types of raw material additives are treated simultaneously in the form of a mixture (i.e., in one pressure vessel) by the method described herein, even if each type of raw material additive is a material insoluble in supercritical fluid, the functional groups of one type of raw material additive may associate with the functional groups of another type of raw material additive through a chemical reaction or interaction, and the multiple types of raw material additives as a whole may behave as a material soluble in supercritical fluid. In this case, since the multiple types of raw material additives as a whole can behave as a material soluble in supercritical fluid, additive microparticles with smaller particle sizes can be obtained for each type of raw material additive compared to when the multiple types of raw material additives are treated individually with supercritical fluid (i.e., in separate pressure vessels).

[0095] <2> Masterbatch The masterbatch according to this embodiment is a masterbatch for use in resin molded products, and resin molded products such as resin layers are manufactured from a resin obtained by kneading this masterbatch with a second raw material resin described below.

[0096] The method for producing a masterbatch according to this embodiment includes obtaining additive particles by the method for producing an additive for a resin molded product described above, and kneading a raw material containing the additive particles and a first raw material resin. The masterbatch obtained by this method contains the additive particles and the first raw material resin.

[0097] Various resins can be used as the first raw material resin. Specific examples of the first raw material resin include polyolefin, polycarbonate, polystyrene, acrylic resins such as polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, polyamides such as nylon 6 and nylon 66, polyacetal, polyphenylene ether, polyesters such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, liquid crystal polymers, polyphenylene sulfide, polyimide, polyamideimide, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyarylate, polyetherimide, fluororesin, polybutylene succinate, and polylactic acid. These resins may be used alone, or blends or alloys of two or more of these may be used.

[0098] Among these resins, for example, polyolefin, polycarbonate and acrylic resin are preferred from the viewpoints of transparency and durability, and polyolefin is preferred from the viewpoints of chemical resistance, durability and moldability.

[0099] In one embodiment, the first raw material resin is a resin (transparent resin) in which the proportion of polyolefin resin is in the range of 90 to 100 mass %.

[0100] Examples of polyolefin resins include polypropylene; polyethylene; polybutene; α-olefins (e.g., propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 4-ethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hex ... and copolymers of ethylene or alpha-olefins with other monomers, such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer.

[0101] The polyolefin resin is preferably a crystalline resin. The polyolefin resin is, for example, a polypropylene resin. The polyolefin resin is preferably a crystalline polypropylene resin.

[0102] The crystalline polypropylene resin may be a homopolymer, a copolymer such as a random copolymer or a block copolymer, or a mixture thereof. The polypropylene contained in the crystalline polypropylene resin may be isotactic polypropylene, syndiotactic polypropylene, or a combination thereof. Furthermore, in the crystalline polypropylene resin, the polypropylenes may have the same pentad fraction or may be a combination of polypropylenes with different pentad fractions. The crystalline polypropylene resin is preferably a propylene homopolymer having an isotactic pentad fraction (mmmm fraction) of 95% or more, more preferably an isotactic pentad fraction (mmmm fraction) of 96% or more, i.e., a highly crystalline homopolypropylene resin that is a homopolymer.

[0103] Here, the isotactic pentad fraction (mmmm fraction) is calculated from the electromagnetic wave absorption rate (EMR) value obtained by resonating a crystalline polypropylene resin at a predetermined resonance frequency using 13C-NMR (nuclear magnetic resonance) measurements using carbon (C) with a mass number of 13. The pentad fraction is related to the atomic arrangement, electronic structure, and molecular microstructure of the resin. The isotactic pentad fraction of a polypropylene resin is the proportion of a specific arrangement consisting of five propylene units, i.e., an arrangement in which all propylene units have the same configuration, as determined by 13C-NMR measurements. It is used as a measure of crystallinity or stereoregularity. The isotactic pentad fraction is one of the important factors that primarily determine the scratch resistance of the surface. Basically, the higher the isotactic pentad fraction, the higher the crystallinity of the sheet, resulting in improved scratch resistance.

[0104] The first raw resin may contain other resins in addition to the polyolefin resin. The other resins may be any resins that are highly compatible with the polyolefin resin. However, the proportion of the polyolefin resin in the resins contained in the masterbatch is preferably in the range of 90 to 100% by mass, as described above, and more preferably in the range of 95 to 100% by mass.

[0105] The additive particles contained in the masterbatch may be one type or two or more types. The amount (total amount) of the additives is preferably in the range of 0.01 to 5 parts by mass, more preferably in the range of 0.05 to 1 part by mass, per 100 parts by mass of the first raw resin. Note that this masterbatch may contain additives other than the additive particles nano-processed by the above method.

[0106] The total proportion of the first raw material resin and the additive fine particles in the masterbatch is preferably in the range of 90 to 100% by mass, and more preferably in the range of 95 to 100% by mass.

[0107] In the production of the masterbatch, the raw material additive is nano-sized to obtain additive fine particles by the above-mentioned method for producing an additive for resin molded products, and these additive fine particles are kneaded with a raw material containing the above-mentioned first raw material resin. This method makes it possible to obtain a masterbatch in which additive fine particles with small particle size variation are highly dispersed in the first raw material resin.

[0108] The raw material containing the additive fine particles and the first raw material resin is preferably kneaded in the presence of a supercritical fluid, in which the amount of the supercritical fluid per 100 parts by mass of the raw material is preferably in the range of 5 to 20 parts by mass.

[0109] The supercritical fluid may be, for example, carbon dioxide or nitrogen. The supercritical fluid is preferably carbon dioxide. Carbon dioxide becomes a supercritical fluid under conditions of 31.1°C or higher and 7.38 MPa or higher.

[0110] A supercritical fluid has a density close to that of a liquid and a diffusion coefficient close to that of a gas. The supercritical fluid easily impregnates the first raw resin in a molten state. Therefore, the supercritical fluid increases the fluidity of the first raw resin in a molten state.

[0111] If the fluidity of the raw material is low, attempting to sufficiently heat the raw material in an area away from the heater may result in the raw material being heated to an excessively high temperature in an area near the heater. Furthermore, if the fluidity of the raw material is low, a large amount of frictional heat may be generated during kneading. This may result in discoloration of the resin, such as yellowing.

[0112] As described above, kneading in the presence of a supercritical fluid can increase the fluidity of the raw materials. This allows the raw materials to be heated uniformly and reduces the frictional heat generated during kneading. This prevents discoloration of the resin due to exposure to excessively high temperatures.

[0113] Furthermore, the supercritical fluid increases the fluidity of the first raw material resin in a molten state, and therefore the additive particles can be distributed in the first raw material resin with an even higher degree of dispersion.

[0114] The kneading may be carried out in a batch system or a continuous system, and for continuous kneading, for example, a kneading extruder can be used.

[0115] When a kneading extruder is used, for example, the raw materials are fed into the kneading extruder, and a supercritical fluid is supplied to the kneading extruder. Alternatively, the raw materials are fed into the kneading extruder, and a fluid is supplied to the kneading extruder, and a supercritical fluid is generated from the fluid within the kneading extruder. The pressure inside the kneading extruder is higher on the downstream side than on the upstream side. Therefore, a fluid such as a gas can be supplied to the kneading extruder, and the fluid can be converted into a supercritical fluid within the kneading extruder.

[0116] The kneading extruder used has, for example, an inlet for introducing the raw materials, an outlet for discharging a mixture obtained by kneading the raw materials, and a supply port provided between the inlet and the outlet. The supercritical fluid or gas is supplied to the kneading extruder from the supply port. As described above, the pressure inside the kneading extruder is higher on the downstream side than on the upstream side. When the supercritical fluid or gas is supplied to the kneading extruder from the supply port provided between the inlet and the outlet, a sufficient amount of supercritical fluid or gas can be supplied to the kneading extruder without interfering with the introduction of raw materials into the kneading extruder.

[0117] The above kneading is carried out by setting the heater temperature preferably in the range of 180 to 240°C, more preferably in the range of 190 to 230°C. If the heater temperature is set too low, an extremely high pressure may be required to generate or maintain a supercritical state within the device, or in the case of continuous kneading, the fluidity of the raw materials upstream may be insufficient. If the heater temperature is set too high, discoloration of the resin may occur.

[0118] <3> Resin and resin molded products The resin according to the embodiment of the present invention contains the masterbatch and a second raw material resin. This resin can be obtained by kneading the masterbatch obtained by the above-described method for producing a masterbatch with a raw material containing the second raw material resin. A resin molded product such as a resin layer, which will be described later, is manufactured from the resin obtained by this method.

[0119] Various resins can be used as the second raw material resin, and those described above for the first raw material resin used in the masterbatch can be used. The second raw material resin preferably has the same composition as the first raw material resin. For example, the first and second raw material resins may each be transparent resins in which the proportion of polyolefin resin is in the range of 90 to 100% by mass, and preferably are transparent resins of the same composition in which the proportion of polyolefin resin is in the range of 90 to 100% by mass.

[0120] The proportion of the masterbatch in the resin according to this embodiment is preferably in the range of 0.01 to 50% by mass, more preferably in the range of 0.1 to 20% by mass. Alternatively, the second raw material resin may be omitted from the resin according to this embodiment. That is, the resin according to another embodiment may be composed of the masterbatch and optional additives.

[0121] The resin according to this embodiment can be used to manufacture a resin molded product. That is, the resin molded product can be obtained by molding the resin according to this embodiment. The resin molded product may have any shape. According to one example, the resin molded product is a resin layer, and this resin layer may be a transparent resin layer.

[0122] The resin layer preferably has a tensile modulus of elasticity in the range of 700 to 2000 MPa, more preferably in the range of 800 to 2000 MPa. The resin layer also preferably has a tensile elongation at break of 200% or more. The tensile elongation at break is, for example, 550% or less.

[0123] Here, the tensile elongation at break is a value that represents the elongation when a sample is pulled at a predetermined speed and breaks, and is the length of the sample at break (L) minus the length of the sample before the test (L0), divided by the length of the sample before the test (L0), expressed as a percentage. A sheet or film with an excessively small value is difficult to elongate and is therefore prone to cracking and whitening during post-processing such as V-groove bending.

[0124] The tensile modulus is a value calculated from the slope of the elastic region in which stress and strain are proportional to each other in the stress-strain curve obtained by the above-mentioned test for tensile elongation at break. A sheet or film with an excessively small modulus is too soft and is likely to cause poor appearance due to wrinkles, for example, when attached to a support. A sheet or film with an excessively large modulus is insufficient in flexibility and is likely to cause poor appearance due to wrinkles, for example, due to reduced adhesion to the support.

[0125] According to one example, the resin layer has a thickness in the range of 20 to 250 μm, and according to another example, the resin layer has a thickness in the range of 30 to 150 μm.

[0126] The resin layer may be one that can be handled by itself, or may be one of the layers contained in a laminate described below. The resin layer or laminate can be used for various products such as packaging materials, electronic components, and decorative sheets.

[0127] The concentration of the additive microparticles in the resin or resin molded product according to this embodiment is, for example, in the range of 0.005 to 1.0% by mass, preferably 0.01 to 1.0% by mass. The additive microparticles can be distributed with high dispersion in the resin or resin molded product, and even a small amount can achieve the significant effects required of the additive. This allows the additive concentration in the resin or resin molded product to be kept low. In this case, it is also possible to prevent bleed-out due to a high additive concentration in the resin or resin molded product.

[0128] <4> Laminate The laminate includes the resin layer and one or more other layers. The laminate can be obtained by laminating one or more other layers onto the resin layer. The laminate may include the resin layer in any position. For example, a laminate including three or more layers may include the resin layer as one of the outermost layers or as an intermediate layer. The laminate may include only one or more of the resin layers. Below, a decorative sheet will be described as an example of a laminate.

[0129] FIG. 1 is a cross-sectional view of a decorative material including a decorative sheet according to one embodiment of the present invention.

[0130] The decorative material 11 shown in FIG. 1 includes a substrate B and a decorative sheet 1 attached thereto. Here, the decorative material 11 is a decorative board. The decorative board may be a flat plate, or may be curved or folded. The decorative material 11 may have a shape other than a plate.

[0131] Here, the substrate B is a plate material. The plate material is, for example, a wood board, an inorganic board, a metal plate, or a composite board made of multiple materials. The substrate B may have a shape other than a plate.

[0132] Decorative sheet 1 is an example of a laminate containing a transparent resin layer as the resin layer. Decorative sheet 1 contains base fabric layer 2, design layer 3, transparent resin layer 4, surface protective layer 5, adhesive layer 7, primer layer 6, and concealing layer 8. The design layer 3, adhesive layer 7, transparent resin layer 4, and surface protective layer 5 are provided in this order from the base fabric layer 2 side on the surface of base fabric layer 2 opposite the surface facing substrate B. The concealing layer 8 and primer layer 6 are provided in this order from the base fabric layer 2 side on the surface of base fabric layer 2 facing substrate B. One or more of the design layer 3, surface protective layer 5, primer layer 6, adhesive layer 7, and concealing layer 8 may be omitted. The elements contained in decorative sheet 1 will be described below in order.

[0133] <4.1> Raw fabric layer The raw fabric layer 2 or its material can be selected arbitrarily from, for example, paper, synthetic resin, synthetic resin foam, rubber, nonwoven fabric, synthetic paper, metal foil, and the like.

[0134] Examples of paper include tissue paper, titanium paper, and resin-impregnated paper. Examples of synthetic resins include polyethylene, polypropylene, polybutylene, polystyrene, polycarbonate, polyester, polyamide, ethylene-vinyl acetate copolymer, polyvinyl alcohol, and acrylic. Examples of rubber include ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-butadiene copolymer rubber, styrene-isoprene-styrene block copolymer rubber, styrene-butadiene-styrene block copolymer rubber, and polyurethane. Examples of nonwoven fabrics include organic and inorganic nonwoven fabrics. Examples of metals for the metal foil include aluminum, iron, gold, and silver.

[0135] When the raw fabric layer 2 contains a synthetic resin, it may further contain inorganic particles. Examples of inorganic particles include particles made of calcium carbonate, talc, or titanium oxide. When the raw fabric layer 2 contains inorganic particles, the non-flammability or flame retardancy of the decorative sheet 1 is improved.

[0136] <4.2> Primer layer When an olefin-based resin is used as the material of the raw fabric layer 2, the surface of the raw fabric layer 2 is often in an inactive state. Therefore, in this case, it is preferable to provide a primer layer 6 between the raw fabric layer 2 and the substrate B. When the raw fabric layer 2 is made of an olefin-based material, the primer layer 6 may be omitted, and the raw fabric layer 2 may be subjected to a surface modification treatment such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, or dichromate treatment in order to improve the adhesion between the raw fabric layer 2 and the substrate B.

[0137] Materials that can be used for the primer layer 6 include, for example, the materials described below for the design layer 3. Since the primer layer 6 is applied to the back surface of the decorative sheet 1, and considering that the decorative sheet 1 will be wound up in web form, an inorganic filler may be added to the primer layer 6 to avoid blocking and increase adhesion to the adhesive. Examples of inorganic fillers include silica, alumina, magnesia, titanium oxide, and barium sulfate.

[0138] <4.3> Hidden layer To impart the decorative sheet 1 with the ability to conceal the substrate B, for example, a colored sheet can be used as the base layer 2, or an opaque concealing layer 8 can be provided. The concealing layer 8 can be made of, for example, the same material as that used for the design layer 3, which will be described later. However, since the purpose of the concealing layer 8 is to provide concealment, it is preferable to use, for example, an opaque pigment, titanium oxide, iron oxide, or the like, as the pigment. Furthermore, to enhance the concealing ability, metals such as gold, silver, copper, and aluminum can also be added to the material of the concealing layer 8. Generally, flake-shaped aluminum pieces are often added.

[0139] <4.4> Picture layer The design layer 3 is a layer formed by printing a design onto the base layer 2 using ink. Examples of ink binders include soluble nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyesters, and modified products thereof, either alone or in combination. The binder may be aqueous, solvent-based, or emulsion-based, and may be either a one-component type or a two-component type that includes a curing agent. The design layer 3 may be formed by curing a layer formed with a curable ink by exposure to ultraviolet light, electron beams, or the like. The most common method is to use a urethane-based ink that is cured with an isocyanate. The ink used to form the design layer 3 may further contain, in addition to the binder, pigments, colorants such as dyes, extender pigments, solvents, and various additives, which are commonly found in inks. Examples of versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.

[0140] In addition to applying ink, it is also possible to apply a design to the pattern layer 3 by vapor deposition or sputtering of various metals. In particular, it is preferable that a light stabilizer be added to the ink. This can suppress deterioration of the decorative sheet 1 itself caused by light degradation of the ink, and extend the life of the decorative sheet 1.

[0141] <4.5>Adhesive layer The adhesive layer 7 is also called a heat-sensitive adhesive layer, an anchor coat layer, or a dry lamination adhesive layer.

[0142] The resin material for the adhesive layer 7 is not particularly limited, and may be appropriately selected from acrylic, polyester, polyurethane, epoxy, and other resin materials. Alternatively, an ethylene-vinyl acetate copolymer resin adhesive may be used as the resin material for the adhesive layer 7. The coating method may be appropriately selected depending on the viscosity of the adhesive. Generally, gravure coating is used, and the adhesive layer 7 is formed on the upper surface of the design layer 3 by gravure coating, followed by lamination of the transparent resin layer 4. The adhesive layer 7 may be omitted if sufficient adhesive strength is obtained between the transparent resin layer 4 and the design layer 3.

[0143] <4.6>Transparent resin layer The transparent resin layer 4 is the transparent resin layer described in detail above. Here, the transparent resin layer 4 has a flat upper surface. The upper surface of the transparent resin layer 4 may be provided with an uneven structure. Methods for providing an uneven structure on the upper surface of the transparent resin layer 4 include, for example, a method of applying heat and pressure while pressing an embossing plate against the upper surface of the transparent resin layer 4 that has been laminated to another layer by various methods, and a method of using a cooling roll having an uneven structure on its surface when forming the transparent resin layer 4 using an extruder. When an uneven structure is provided on the upper surface of the transparent resin layer 4, it is also possible to further improve the design by filling the recesses with ink.

[0144] <4.7>Surface protective layer The surface protective layer 5 is a colorless and transparent resin layer. Here, an uneven structure is provided on the upper surface of the surface protective layer 5. The upper surface of the surface protective layer 5 may also be flat.

[0145] The surface protection layer 5 contains a cured resin. This resin is, for example, a thermosetting resin, an ionizing radiation curable resin, or a combination thereof. The resin may be, for example, aqueous, emulsion, solvent-based, or solventless. Here, "ionizing radiation" refers to charged particle beams such as electron beams. Ionizing radiation curable resins are cured by irradiation with ionizing radiation. Ionizing radiation curable resins can also be cured by irradiation with ultraviolet light.

[0146] As the thermosetting resin, a two-component curing urethane-based thermosetting resin is preferably used. Urethane-based thermosetting resins are suitable from the viewpoints of workability, cost, and the cohesive strength of the resin itself. As the urethane-based resin, a resin obtained by reacting an acrylic polyol with an isocyanate may be used. The isocyanate may be appropriately selected from, for example, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (HXDI), and trimethylhexamethylene diisocyanate (TMDI); their derivatives such as adducts, biuret compounds, and isocyanurates; and prepolymers thereof. In consideration of weather resistance, it is preferable to use a material based on hexamethylene diisocyanate (HMDI) or isophorone diisocyanate (IPDI), which have a linear molecular structure.

[0147] As the ionizing radiation curable resin, known materials such as various monomers and commercially available oligomers can be used, for example, acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins can be used. The ionizing radiation curable resin may be either an aqueous resin or a non-aqueous (organic solvent-based) resin. The acrylic resin can be appropriately selected from, for example, polyester acrylate resins, epoxy acrylate resins, urethane acrylate resins, and acrylic acrylate resins. In particular, it is preferable to use urethane acrylate resins or acrylic acrylate resins, which have good weather (light) resistance. From the viewpoint of workability, it is preferable to cure the ionizing radiation curable resin with active energy rays such as ultraviolet rays or electron beams.

[0148] As the mixture of thermosetting resin and ionizing radiation curable resin, it is preferable to use a mixture of a urethane resin as a thermosetting resin obtained by reacting an acrylic polyol with an isocyanate, and a urethane acrylate resin as a photocurable resin, which is particularly advantageous in terms of improving surface hardness, suppressing cure shrinkage, and adhesion to inorganic fine particles.

[0149] The surface protective layer 5 may further include inorganic particles. Examples of the inorganic particles include particles made of alumina, silica, boehmite, iron oxide, magnesium oxide, or diamond. The average particle size of the inorganic particles is, for example, in the range of 1 to 100 μm, and in another example, in the range of 1 to 30 μm.

[0150] The inorganic particle content of the surface protective layer 5 is, for example, in the range of 0.1 to 30 parts by mass, and in another example, in the range of 1 to 20 parts by mass, per 100 parts by mass of the resin component. Inclusion of inorganic particles in the surface protective layer 5 improves its scratch resistance. However, excessively high inorganic particle content may reduce transparency due to the light scattering effect of the inorganic particles, or may result in increased costs. The surface protective layer 5 can be formed by known methods. A surface protective layer 5 having a concave-convex structure on its upper surface can be formed by forming a coating film made of an ionizing radiation-curable resin, followed by a first irradiation step in which the coating film is irradiated with light having a wavelength of 200 nm or less (first radiation), and a second irradiation step in which the coating film is irradiated with ionizing radiation such as electron beams or ultraviolet light having a longer wavelength than the first radiation as the second radiation, in that order. Alternatively, the surface protective layer 5 having a concave-convex structure on its upper surface can be formed by forming a coating film made of an ionizing radiation-curable resin or a thermosetting resin, pressing a plate against the coating film, curing the coating film in this state, and then removing the plate from the cured film. A leaf surface protective layer having a flat upper surface can be formed by forming a coating film made of an ionizing radiation-curable resin or a thermosetting resin and curing the coating film. The coating film can be formed by various printing methods such as gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, and ink jet printing, and various coating methods such as roll coating, knife coating, microgravure coating, and die coating. [Example]

[0151] The following describes examples of the present invention.

[0152] <Example 1> (Production of additive fine particles) Additive fine particles were produced according to the method of the first embodiment as follows.

[0153] First, lithium myristate was synthesized as a raw material additive according to the following procedure. A stir bar and 9.746 g of myristic acid were placed in a 500 mL beaker and stirred in an oil bath set to 65 °C to melt the myristic acid. After melting, 1.794 g of lithium hydroxide monohydrate was gradually added and stirring continued until a free-flowing powder was obtained. The resulting powder was then washed twice with 100 mL of pure water and four times with 100 mL of ethanol. Finally, 100 mL of ethanol was added and the mixture was stirred at 60 °C for 10 minutes. After cooling to room temperature, the solid was collected by suction filtration and vacuum dried to obtain 7.980 g of lithium myristate.

[0154] It was previously confirmed that the obtained lithium myristate was insoluble in supercritical carbon dioxide according to the procedure described in the detailed description.

[0155] A raw material additive (lithium myristate, average particle size: 8.9 μm) was placed in a 500 mL high-pressure stainless steel vessel equipped with a stirring blade, at 1% (w / v) of the vessel's volume, and the vessel was sealed. Carbon dioxide was then injected to a pressure of 30 MPa at 40°C, creating a supercritical state. The mixture was held at 30 MPa for 30 minutes while stirring at 300 rpm at 40°C. The carbon dioxide was then removed, and the pressure was reduced to atmospheric pressure. As a result, additive microparticles with an average particle size of 4.8 μm were obtained in the vessel.

[0156] (Masterbatch manufacturing) A masterbatch containing the above additive fine particles and a polyolefin resin was produced as follows.

[0157] The polyolefin resin used was a highly crystalline homopolypropylene resin with an isotactic pentad fraction of 97.8%, a melt flow rate (MFR) of 15 g / 10 min (230 °C), and a molecular weight distribution (MWD; Mw / Mn) of 2.3. To this polyolefin resin, 10,000 ppm of the additive particles was added. Other additives included 500 ppm of a hindered phenol antioxidant (Irganox® 1010, manufactured by BASF), 20,000 ppm of a benzotriazole ultraviolet absorber (Tinuvin® 328, manufactured by BASF), and 20,000 ppm of a hindered amine light stabilizer (Chimasorb® 944, manufactured by BASF). The amount in ppm is the mass ratio of each additive based on the total amount of the polyolefin resin and all additives.

[0158] The obtained raw materials were kneaded using a kneading extruder. Here, the heater temperature was set to 230°C. The strands extruded through the strand die were cooled and then cut to obtain a masterbatch (additive fine particle concentration: 1% by mass).

[0159] (Manufacturing transparent resin sheets) A transparent resin sheet was produced using the masterbatch. Specifically, 10 parts by mass of the masterbatch was added to 100 parts by mass of the same polyolefin resin as used in the production of the masterbatch, and 500 ppm of a hindered phenol-based antioxidant (Irganox (registered trademark) 1010: manufactured by BASF) was further added. The mixture was then extruded using a melt extruder to form a transparent resin layer in an 80 μm thick transparent resin sheet (additive fine particle concentration: 0.1% by mass). Next, both sides of the transparent resin sheet were subjected to a corona treatment to set the surface wetting tension to 40 dyn / cm or more.

[0160] (Decorative sheet manufacturing) A decorative sheet was manufactured using the above transparent resin sheet. Specifically, first, a base fabric layer having a thickness of 70 μm and having hiding properties was prepared. Next, a pattern was printed on one side of the base fabric layer using a two-component curing urethane ink (V180: manufactured by Toyo Ink Co., Ltd.) to form a design layer. A primer coat was applied to the other side of the base fabric layer to form a primer layer. Next, the base fabric layer and the above transparent resin sheet were bonded together by dry lamination so that the design layer faced the transparent resin layer. In this dry lamination, a dry lamination adhesive (Takelac (registered trademark) A540: manufactured by Mitsui Chemicals, Inc.) was applied at 2 g / m 2 Next, the upper surface of the transparent resin sheet was pressed using an embossing die roll to create a concave-convex structure. After that, a two-component curing urethane top coat (W184: manufactured by DIC Graphics Corporation) was applied to the transparent resin sheet at a coating amount of 3 g / m. 2 The coating was then cured to form a surface protective layer. In this way, a decorative sheet having a thickness of 154 μm was obtained.

[0161] <Example 2> In this example, additive fine particles, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1, except that in the manufacturing process of the additive fine particles, a rosin metal salt nucleating agent (Pine Crystal KR-50M, average particle size: 4.4 μm, Arakawa Chemical Industries Co., Ltd.) was used as the raw material additive instead of lithium myristate. The average particle size of the additive fine particles produced in this example was 3.5 μm.

[0162] It was previously confirmed that Pine Crystal KR-50M is insoluble in supercritical carbon dioxide according to the procedure described in the detailed description.

[0163] <Example 3> In this example, additive fine particles were produced according to the method of the second embodiment as follows. In this example, instead of using lithium myristate as a raw material additive, a rosin metal salt nucleating agent (trade name: Pine Crystal KR-50M, average particle size: 4.4 μm, Arakawa Chemical Industries Co., Ltd.) was used.

[0164] Carbon dioxide was pumped into an empty high-pressure cell and the pressure was increased to 30 MPa. The temperature inside the high-pressure cell was 40°C. Meanwhile, 50 mL of hexane and 500 mg of Pine Crystal KR-50M were added to a separate container, and the Pine Crystal KR-50M was dissolved in the hexane. This solution was sprayed into the high-pressure cell through a nozzle using a pump. Here, the amount of carbon dioxide per 100 parts by mass of raw material additive was 1,000 parts by mass. The solution was fed into the high-pressure cell at a rate of 1 mL / min per 500 g of carbon dioxide.

[0165] An outlet equipped with a filter was provided at the bottom of the high-pressure cell. The generated fine particles were collected on the filter. The average particle size of the obtained additive fine particles was 2.1 μm. The hexane was transferred from the outlet equipped with a filter and separated and removed.

[0166] Using the above additive fine particles, a master batch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1.

[0167] <Example 4> In this example, additive fine particles were produced according to the method of the third embodiment as follows. In this example, instead of using lithium myristate as a raw material additive, a rosin metal salt nucleating agent (trade name: Pine Crystal KR-50M, average particle size: 4.4 μm, Arakawa Chemical Industries Co., Ltd.) was used.

[0168] A raw material additive (trade name: Pine Crystal KR-50M, average particle size: 4.4 μm) was placed in a 500 mL high-pressure stainless steel vessel equipped with a stirring blade and sealed in an amount of 1% (w / v) of the vessel's volume. Carbon dioxide was injected to a pressure of 30 MPa at 130°C to create a supercritical state. The mixture was stirred at 300 rpm at 130°C and maintained at a pressure of 30 MPa for 30 minutes to melt the raw material additive in the supercritical carbon dioxide. This yielded a fluid containing the melted raw material additive and supercritical carbon dioxide. This fluid was then sprayed through a nozzle at atmospheric pressure to obtain additive microparticles.

[0169] The average particle size of the additive fine particles produced in this example was 2.9 μm. Using the additive fine particles described above, a master batch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1.

[0170] <Example 5> In this example, additive fine particles (average particle size: 3.5 μm) and a master batch (additive fine particle concentration: 1% by mass) were produced by the same method as in Example 2. Thereafter, a transparent resin sheet (additive fine particle concentration: 1% by mass) was produced by the same method as in Example 2, except that in the transparent resin sheet production process, resins other than the master batch (polyolefin resins) were omitted as raw resins, and only the master batch was used. A decorative sheet was produced by the same method as in Example 2 using the obtained transparent resin sheet.

[0171] <Example 6> In this example, additive fine particles (average particle size: 3.5 μm) and a master batch (additive fine particle concentration: 1 mass %) were produced by the same method as in Example 2. Thereafter, a transparent resin sheet (additive fine particle concentration: 0.3 mass %) was produced by the same method as in Example 2, except that in the transparent resin sheet production process, the raw material resin composition was changed to 70 parts by mass of polyolefin resin and 30 parts by mass of the master batch. A decorative sheet was produced by the same method as in Example 2 using the obtained transparent resin sheet.

[0172] <Example 7> In this example, additive fine particles (average particle size: 3.5 μm) and a masterbatch (additive fine particle concentration: 1% by mass) were produced by the same method as in Example 2. Thereafter, a transparent resin sheet (additive fine particle concentration: 0.05% by mass) was produced by the same method as in Example 2, except that in the transparent resin sheet production process, the raw material resin composition was changed to 95 parts by mass of polyolefin resin and 5 parts by mass of the masterbatch. A decorative sheet was produced by the same method as in Example 2 using the obtained transparent resin sheet.

[0173] <Example 8> In this example, additive fine particles (average particle size: 3.5 μm) and a master batch (additive fine particle concentration: 1% by mass) were produced by the same method as in Example 2. Thereafter, a transparent resin sheet (additive fine particle concentration: 0.01% by mass) was produced by the same method as in Example 2, except that in the transparent resin sheet production process, the raw material resin composition was changed to 99 parts by mass of polyolefin resin and 1 part by mass of master batch. A decorative sheet was produced by the same method as in Example 2 using the obtained transparent resin sheet.

[0174] <Comparative Example 1> In this example, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1, except that the process for producing additive fine particles was omitted and lithium myristate was used as a raw additive instead of additive fine particles in the process for producing the masterbatch.

[0175] <Comparative Example 2> In this example, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 2, except that the process for producing additive fine particles was omitted and Pine Crystal KR-50M was used as a raw material additive instead of the additive fine particles in the masterbatch production process.

[0176] <Example 9> In this example, instead of using lithium myristate as a raw additive in the additive microparticle manufacturing process, a hindered amine light stabilizer (Chimassorb (registered trademark) 2020, average particle size: 1000 μm or more (pellet form), manufactured by BASF) was used, and in the masterbatch manufacturing process, no hindered amine light stabilizer (Chimassorb (registered trademark) 944, manufactured by BASF) was added as another additive. The additive microparticles, masterbatch, transparent resin sheet, and decorative sheet were manufactured in the same manner as in Example 1, except that the average particle size of the additive microparticles manufactured in this example was 1000 μm or more. The additive microparticles manufactured in this example retained their pellet-like shape and had the same average particle size as the raw additive, but had changed into a brittle agglomerated state and could easily change into powder when external force was applied.

[0177] The insolubility of Chimassorb® 2020 in supercritical carbon dioxide was previously confirmed according to the procedure described in the detailed description.

[0178] <Comparative Example 3> In this example, the masterbatch, transparent resin sheet, and decorative sheet were produced in the same manner as in Example 9, except that the additive fine particle production process was omitted, and neither the additive fine particles nor Chimassorb (registered trademark) 2020 as a raw material additive was added to the raw material resin in the masterbatch production process.

[0179] <Comparative Example 4> In this example, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 9, except that the process for producing additive fine particles was omitted and Chimassorb (registered trademark) 2020 was used as a raw material additive instead of the additive fine particles in the masterbatch production process.

[0180] <Example 10> In this example, an additive, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1, except that talc (Microace (registered trademark) P-3, average particle size: 5.0 μm, manufactured by Nippon Talc Co., Ltd.) was used as the raw material additive instead of lithium myristate in the production process of the additive fine particles. The average particle size of the additive fine particles produced in this example was 4.5 μm.

[0181] It was previously confirmed that MicroAce (registered trademark) P-3 is insoluble in supercritical carbon dioxide according to the procedure described in the detailed description.

[0182] <Comparative Example 5> In this example, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 10, except that the process for producing additive fine particles was omitted and MicroAce (registered trademark) P-3 was used as a raw material additive instead of the additive fine particles in the masterbatch production process.

[0183] <Example 11> In this example, additive fine particles were produced according to the method of the first embodiment as follows. A raw material additive was prepared by mixing lithium myristate (average particle size: 8.9 μm) and a rosin metal salt-based nucleating agent (Pine Crystal KR-50M, average particle size: 4.4 μm, Arakawa Chemical Industries, Ltd.) in a 1:1 mass ratio. A 500 mL high-pressure stainless steel vessel equipped with a stirring blade was charged with 1% (w / v) of the raw material additive relative to the vessel's volume, sealed, and carbon dioxide was injected to a pressure of 30 MPa at 40°C to create a supercritical state. The mixture was maintained at 30 MPa for 30 minutes while stirring at 300 rpm at 40°C. The carbon dioxide was then removed and the pressure was reduced to atmospheric pressure. As a result, additive microparticles consisting of a mixture of lithium myristate microparticles with an average particle size of 4.8 μm and Pine Crystal KR-50M microparticles with an average particle size of 3.5 μm were obtained in the vessel.

[0184] Using the above additive fine particles, a master batch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1.

[0185] <Example 12> In this example, additive fine particles were produced according to the method of the second embodiment as follows. A raw material additive was prepared by mixing lithium myristate (average particle size: 8.9 μm) and a rosin metal salt-based nucleating agent (Pine Crystal KR-50M, average particle size: 4.4 μm, Arakawa Chemical Industries, Ltd.) in a 1:1 mass ratio. Carbon dioxide was pumped into an empty high-pressure cell and the pressure was increased to 30 MPa. The temperature inside the high-pressure cell was 40°C. Meanwhile, 50 mL of hexane and 500 mg of raw material additive were added to a separate container. Pine Crystal KR-50M dissolved in hexane, but lithium myristate did not. This liquid was sprayed into the high-pressure cell through a nozzle using a pump. Here, the amount of carbon dioxide per 100 mass parts of raw material additive was 1,000 mass parts. The solution was supplied to the high-pressure cell at a rate of 1 mL / min per 500 g of carbon dioxide.

[0186] An outlet equipped with a filter was provided at the bottom of the high-pressure cell. The generated fine particles were collected on the filter. The obtained additive fine particles were a mixture of lithium myristate fine particles with an average particle size of 4.5 μm and Pine Crystal KR-50M fine particles with an average particle size of 2.1 μm. The hexane was transferred from the outlet equipped with a filter and separated and removed.

[0187] Using the above additive fine particles, a master batch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 1.

[0188] <Comparative Example 6> In this example, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 11, except that the process for producing additive fine particles was omitted and a raw material additive (a mixture of lithium myristate and Pine Crystal KR-50M) was used instead of additive fine particles in the process for producing the masterbatch.

[0189] <Example 13> In this example, lithium myristate (average particle size: 8.9 μm) and a hindered amine light stabilizer (Chimasorb (registered trademark) 2020, average particle size: 1000 μm or more (pellet form), manufactured by BASF) were mixed in a mass ratio of 1:1 to prepare a raw material additive. Additive fine particles, a master batch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 11, except that this raw material additive was used instead in the additive fine particle production process.

[0190] The additive microparticles produced in this example were a mixture of lithium myristate microparticles with an average particle size of 4.8 μm and Chimassorb® 2020 microparticles. The Chimassorb® 2020 microparticles contained in the additive microparticles retained their pellet-like shape and had an average particle size similar to that contained in the raw additive, but had changed into a brittle agglomerated state and could easily change into powder when external force was applied.

[0191] <Example 14> In this example, lithium myristate (average particle size: 8.9 μm), a hindered amine light stabilizer (Chimasorb (registered trademark) 2020, average particle size: 1000 μm or more (pellet form), manufactured by BASF), and a hindered phenol antioxidant (Irganox (registered trademark) 1010, average particle size: 2.2 μm) were mixed in a mass ratio of 1:1:1 to prepare a raw material additive. Additive fine particles, master batches, transparent resin sheets, and decorative sheets were produced in the same manner as in Example 11, except that this raw material additive was used instead in the additive fine particle production process.

[0192] The additive microparticles produced in this example were a mixture of lithium myristate microparticles with an average particle size of 4.8 μm, Chimassorb® 2020 microparticles, and Irganox® 1010 microparticles with an average particle size of 1.5 μm. The Chimassorb® 2020 microparticles contained in the additive microparticles retained their pellet-like shape and had the same average particle size as those contained in the raw additive, but had changed into a brittle agglomerated state and could easily change into powder when external force was applied.

[0193] The insolubility of Irganox® 1010 in supercritical carbon dioxide was previously confirmed according to the procedure described in the detailed description.

[0194] <Comparative Example 7> In this example, a masterbatch, a transparent resin sheet, and a decorative sheet were produced in the same manner as in Example 13, except that the process for producing additive fine particles was omitted and a raw material additive (a mixture of lithium myristate and Chimassorb (registered trademark) 2020) was used instead of the additive fine particles in the process for producing the masterbatch.

[0195] <Comparative Example 8> In this example, the master batch, transparent resin sheet, and decorative sheet were produced in the same manner as in Example 14, except that the process for producing additive fine particles was omitted and raw material additives (a mixture of lithium myristate, Chimassorb (registered trademark) 2020, and Irganox (registered trademark) 1010) were used instead of additive fine particles in the master batch production process.

[0196] <Evaluation of additives> (Evaluation of particle size) The additives produced in Examples 1 to 8 and 10 to 14, and the raw material additives used to produce the masterbatches in Comparative Examples 1, 2 and 5 to 8 were observed using an electron microscope SU8020 (Hitachi High-Tech).

[0197] First, the additive or raw material additive was placed on a carbon support tape. Then, the additive or raw material additive was platinum coated. This prepared the sample for electron microscope observation. The prepared sample was placed in the observation chamber. Observation was carried out at a magnification of 5000 times, and the part of the observation screen where the additive fine particles or raw material additive accounted for 75% or more was saved as an image. Then, a 100 μm 2 The particle diameters of all particles within the range were measured and the average value was calculated. 2 When there are fewer than 30 particles within the range, the observation range is reduced to 100 μm. 2The particle size of 30 or more particles was measured by spreading the sample in an electron microscope.

[0198] <Evaluation of transparent resin sheets> (Evaluation of bleed-out properties) The transparent resin sheet was left at room temperature for one week after production. Two 5 cm x 5 cm pieces were then cut from the transparent resin sheet. One of the pieces was placed in an oven at 80°C ± 3°C and heated for one hour. The remaining piece was not heated. These sheets were immersed in 10 mL of methanol for 15 minutes to extract or disperse the additives that had bled out onto the surface of the sheet into the methanol. This methanol solution was quantitatively analyzed using high-performance liquid chromatography (HPLC). The amounts of additives or their decomposition products (hereinafter also referred to as bleed-out amounts) were analyzed for both the heated and unheated sheets. Based on the results of the HPLC analysis, a heated sheet with a bleed-out amount of 1.5 times or more that of the unheated sheet was evaluated as "bleed-out present," while a heated sheet with a bleed-out amount of less than 1.5 times was evaluated as "no bleed-out present."

[0199] Transparent resin sheets manufactured using talc as a raw material additive (Example 10, Comparative Example 5) were evaluated for bleed-out properties as follows. Two 5 cm x 5 cm pieces were cut from the transparent resin sheet, and one of the pieces was placed in an oven at 80°C ± 3°C and heated for 1 hour. The remaining piece was not heated. These sheets were not extracted into methanol, but Fourier transform infrared spectroscopy (FT-IR analysis) of the sheet surface was performed using an attenuated total reflectance (ATR) method (Ge prism). This analyzed the amount of talc on the sheet surface. When the amount of talc detected on the heated sheet surface was 1.2 times or more compared to the unheated sheet, it was evaluated as "bleed-out present," and when it was less than 1.2 times, it was evaluated as "bleed-out absent."

[0200] (Tensile test) Test pieces for tensile tests were cut from the transparent resin sheet using a Super Dumbbell Cutter (manufactured by Dumbbell Co., Ltd.) conforming to JIS K-7127 Type 4 test pieces. The obtained test pieces were set in a tensile testing machine (manufactured by Tensilon Co., Ltd.) and pulled at a pulling rate of 50 mm / min. The ratio of the length of the test piece just before it broke to the length before the test was calculated as the tensile breaking elongation. Furthermore, the tensile modulus was calculated from the slope of the stress-strain curve obtained in the test in the elastic region where stress and strain are proportional.

[0201] (Haze value measurement test) The haze value referred to here is a value obtained by subtracting the ratio of the amount of parallel transmitted light, which is the sum of the amount of linear components of the light rays emitted from one side of an object, to the amount of total incident light (parallel transmittance), from the ratio of the total transmitted light, which is the sum of the amount of all light rays emitted from the other side of the object, to the amount of total incident light (total transmittance), when light emitted from an incandescent light source is incident on one side of the object, and dividing the result (diffuse transmittance) by the total light transmittance, expressed as a percentage. The smaller the haze value of an object, the higher the transparency of the object.

[0202] The haze value of an object made of a transparent resin is determined by internal haze, which depends on the internal state of the object, such as the degree of crystallinity in the crystalline portion and the size of the spherulite, and external haze, which depends on the surface state of the object, such as the presence or absence of irregularities on the entrance and exit surfaces. In this specification, when simply referring to the haze value, it means a value determined by the internal haze and external haze.

[0203] Here, the haze value measurement test was performed on each transparent resin sheet using a haze value measurement tester (NDH2000: manufactured by Nippon Denshoku Industries Co., Ltd.). Specifically, first, a blank measurement was performed with nothing attached to the sample holder. Next, a sample transmittance measurement was performed with the transparent resin sheet attached to the sample holder as a sample. Then, the ratio of the value obtained by the sample transmittance measurement to the value obtained by the blank measurement was calculated as a percentage, and the haze value was calculated from these transmittances.

[0204] <Evaluation of decorative sheets> (Pencil hardness test) Pencils with lead hardnesses of 2B, B, HB, F, H, 2H, and 3H were prepared. The tip of the pencil lead was placed against the upper surface of the surface protection layer of the decorative sheet, and the angle formed by the pencil's longitudinal direction was fixed at 45±1°. A load of 1 kg was applied to the pencil, and it was then slid to determine whether scratches were formed on the decorative sheet (in accordance with the old JIS standard JISK5400). The test was performed in ascending order of hardness with the pencil, and the hardness at which a scratch was first formed was taken as the surface hardness of the decorative sheet.

[0205] (V-groove bending process suitability test) A medium-density fiberboard (MDF) was prepared as the substrate. Next, a decorative sheet was attached to one side of the substrate using a urethane adhesive to produce a decorative material. Next, a groove with a V-shaped cross section (V-groove) was formed on the other side of the substrate attached to the substrate. This V-groove was formed so that its bottom reached the boundary between the substrate and the decorative sheet and so as not to scratch the decorative sheet. Next, the decorative material was folded at a 90° angle along the V-groove so that the decorative sheet side formed a mountain fold. The mountain fold of the decorative sheet was then observed with an optical microscope to check for defects such as whitening or cracks at the mountain fold, and post-processability was evaluated according to the following criteria. A: No defects such as whitening or cracks were observed. B: Defects such as whitening and cracks were observed.

[0206] (weather resistance) For Example 9, Comparative Example 3, Comparative Example 4, Example 13, Example 14, Comparative Example 7, and Comparative Example 8, the weather resistance was evaluated. A carbon arc weather resistance test was conducted in accordance with JIS B 7753 using a weather resistance tester (Sunshine Weather Meter, manufactured by Suga Test Instruments Co., Ltd.). The test conditions were a weather resistance time of 4000 hours. The change in appearance of each transparent resin film before and after the weather resistance test was evaluated based on the following criteria. Evaluation B indicates that the film satisfies the weather resistance required for applications such as decorative sheets. A: No change at all B: No whitening or cracks, but some loss of gloss and slight fading C: Whitening, cracks, or partial destruction or breakage.

[0207] <Evaluation results> The results of the above evaluations are summarized in Tables 1 to 5.

[0208] [Table 1]

[0209] [Table 2]

[0210] [Table 3]

[0211] [Table 4]

[0212] [Table 5]

[0213] In Tables 1 to 5, "normal" in the "mixing method" column means that the masterbatch was produced by simply mixing the materials without any special mixing conditions such as in the presence of a supercritical fluid. In addition, for Comparative Examples 1, 2, and 5 to 8, the masterbatches were produced using raw material additives instead of additive microparticles, so in Tables 1 and 3 to 5, the "average particle size (μm)" column indicates the average particle size of the raw material additives.

[0214] As shown in Table 1, when additive microparticles were produced using a nucleating agent as a raw material additive and a transparent resin sheet was produced using the resulting additive microparticles, bleed-out of the additive microparticles was eliminated, the haze of the transparent resin sheet was reduced, and the tensile modulus and tensile elongation at break of the transparent resin sheet were increased (see Examples 1 to 8 and Comparative Examples 1 and 2). Furthermore, as shown in Table 1, when additive microparticles were produced using a nucleating agent as a raw material additive and a decorative sheet was produced using the resulting additive microparticles, the decorative sheet was able to achieve both excellent scratch resistance and excellent post-processability (see Examples 1 to 8 and Comparative Examples 1 and 2).

[0215] As shown in Table 2, when additive microparticles were produced using a light stabilizer as a raw material additive and a transparent resin sheet was produced using the resulting additive microparticles, there was no bleeding out of the additive microparticles (see Example 9, Comparative Examples 3 and 4). Also, as shown in Table 2, when additive microparticles were produced using a light stabilizer as a raw material additive and a decorative sheet was produced using the resulting additive microparticles, the decorative sheet showed excellent weather resistance (see Example 9, Comparative Examples 3 and 4).

[0216] Note that the additive microparticles produced in Example 9 and the raw additives used to produce the masterbatches in Comparative Examples 3 and 4 were all pellet-shaped, so their particle sizes were not evaluated using an electron microscope. The additive microparticles produced in Example 9 retained their pellet-like shape, but changed into a brittle aggregate state, and easily turned into powder when external force was applied. Therefore, it is thought that the additive microparticles produced in Example 9 easily turned into powder when mixed with the raw resin to produce the masterbatch, and as a result, contributed to improving the weather resistance of the decorative sheet.

[0217] As shown in Table 3, when additive microparticles were produced using talc, a nucleating agent, as a raw material additive, and a transparent resin sheet was produced using the resulting additive microparticles, bleeding out of the additive microparticles was eliminated, the haze of the transparent resin sheet was reduced, and the tensile modulus and tensile elongation at break of the transparent resin sheet were increased (see Example 10 and Comparative Example 5).

[0218] As shown in Tables 4 and 5, when two or more (multiple) raw material additives were treated simultaneously as a mixture with a supercritical fluid, similar results were obtained as when one raw material additive was treated with a supercritical fluid.

[0219] That is, as shown in Table 4, when a transparent resin sheet was produced using a mixture of two types of nucleating agents and treated simultaneously with a supercritical fluid, the resulting additive fine particles eliminated bleed-out of the additive fine particles, reduced the haze of the transparent resin sheet, and increased the tensile modulus and tensile elongation at break of the transparent resin sheet (see Examples 11 and 12, Comparative Example 6). Also, as shown in Table 4, when a decorative sheet was produced using a mixture of two types of nucleating agents and treated simultaneously with a supercritical fluid, the resulting additive fine particles provided a decorative sheet that could achieve both excellent scratch resistance and excellent post-processability (see Examples 11 and 12, Comparative Example 6).

[0220] Furthermore, as shown in Table 5, when a mixture of a nucleating agent and a light stabilizer was treated simultaneously with a supercritical fluid and the resulting additive fine particles were used to produce a transparent resin sheet, bleed-out of the additive fine particles was eliminated, the haze of the transparent resin sheet was reduced, and the tensile modulus and tensile elongation at break of the transparent resin sheet were increased (see Example 13 and Comparative Example 7). Also, as shown in Table 5, when a mixture of a nucleating agent and a light stabilizer as raw material additives was treated simultaneously with a supercritical fluid and the resulting additive fine particles were used to produce a decorative sheet, the decorative sheet exhibited excellent weather resistance in addition to excellent scratch resistance and excellent post-processability (see Example 13 and Comparative Example 7).

[0221] Furthermore, as shown in Table 5, when a mixture of a nucleating agent, a light stabilizer, and an antioxidant was treated simultaneously with a supercritical fluid and the resulting additive fine particles were used to produce a transparent resin sheet, bleed-out of the additive fine particles was eliminated, the haze of the transparent resin sheet was reduced, and the tensile modulus and tensile elongation at break of the transparent resin sheet were increased (see Example 14 and Comparative Example 8). Also, as shown in Table 5, when a mixture of a nucleating agent, a light stabilizer, and an antioxidant was treated simultaneously with a supercritical fluid and the resulting additive fine particles were used to produce a decorative sheet, the decorative sheet exhibited excellent weather resistance in addition to excellent scratch resistance and excellent post-processability (see Example 14 and Comparative Example 8). [Explanation of symbols]

[0222] 1...decorative sheet, 2...base layer, 3...pattern layer, 4...transparent resin layer, 5...surface protection layer, 6...primer layer, 7...adhesive layer, 8...hiding layer, 11...decorative material, B...base material.

Claims

1. A method for producing an additive for a resin molded product, comprising using a supercritical fluid to obtain an additive having a smaller average particle size than the raw additive from a raw additive that is insoluble in the supercritical fluid.

2. 2. The method for producing an additive for a resin molded product according to claim 1, wherein the additive has an average particle size smaller than that of the raw material additive, and the additive is obtained by stirring a fluid containing the supercritical fluid and the raw material additive.

3. 2. The method for producing an additive for a resin molded product according to claim 1, wherein the supercritical fluid is mixed with a solution containing the raw material additive and a solvent that dissolves the raw material additive, thereby precipitating the additive having a smaller average particle size than the raw material additive.

4. 2. The method for producing an additive for a resin molded product according to claim 1, wherein the raw material additive is melted in the supercritical fluid, and a fluid containing the melted raw material additive and the supercritical fluid is decompressed to precipitate the additive having a smaller average particle size than the raw material additive.

5. 2. The method for producing an additive for a resin molded product according to claim 1, wherein the raw material additive has an average particle size of 4 μm or more, and the additive having a smaller average particle size than the raw material additive has an average particle size of 5000 nm or less.

6. The method for producing an additive for a resin molded product according to claim 1, wherein the additive is a nucleating agent.

7. 2. The method for producing an additive for a resin molded product according to claim 1, wherein the additive is a plastic decomposition inhibitor.

8. 2. The method for producing an additive for a resin molded product according to claim 1, wherein the supercritical fluid comprises carbon dioxide.

9. Producing the additive by the method for producing an additive for a resin molded product according to any one of claims 1 to 8; kneading a raw material containing a first raw material resin and the additive; A method for producing a masterbatch comprising:

10. The method for producing a masterbatch according to claim 9, wherein the raw materials are kneaded in the presence of a supercritical fluid.

11. The method for producing a masterbatch according to claim 9, wherein the first raw material resin is a resin in which the proportion of polyolefin resin is in the range of 90 to 100 mass %.

12. Producing the masterbatch by the method for producing the masterbatch according to claim 9; kneading a raw material containing the masterbatch and a second raw material resin; A method for producing a resin comprising the steps of:

13. The method for producing a resin according to claim 12, wherein the first raw resin and the second raw resin are each independently a resin having a polyolefin resin content in the range of 90 to 100% by mass.

14. Producing the resin by the resin producing method according to claim 12; molding the resin to produce a resin molded product; A method for manufacturing a resin molded product comprising the steps of:

15. The method for producing a resin molded product according to claim 14, wherein the concentration of the additive in the resin molded product is set to be within a range of 0.005 to 1.0% by mass.

16. The method for producing a resin molded product according to claim 14, wherein the resin molded product is a resin layer.

17. forming the resin layer by the method for producing a resin molded product according to claim 16; laminating one or more other layers on the resin layer; A method for producing a laminate comprising the steps of:

18. The method for producing a laminate according to claim 17, wherein the laminate is a decorative sheet.

19. A resin molding additive obtained by the method for producing an additive for resin molding according to any one of claims 1 to 8.

20. A masterbatch obtained by the method for producing a masterbatch according to claim 9.

21. A resin molded product obtained by the method for producing a resin molded product according to claim 14.

22. A resin layer obtained by the method for producing a resin molded article according to claim 16.

23. A laminate obtained by the method for producing a laminate according to claim 17.

24. 24. The laminate according to claim 23, which is a decorative sheet.

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