A device for calculating molten physical properties, a method for calculating molten physical properties, a computer program, a method for improving molding defects in resin molded articles, and a resin molded article and a method for manufacturing resin molded articles using the same.

Abstract

The present invention provides a melt property calculation device that can simultaneously determine the melt properties necessary to improve various molding defects (dimensional defects, strength defects, shape defects, appearance defects, etc.) in resin molded articles made of at least one type of thermoplastic resin, under multiple conditions (temperature, resin type, etc.). [Solution] A melting property calculation device for calculating the melting properties of a resin molded article made of at least one type of thermoplastic resin, comprising: a receiving means for receiving at least one variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions; a recording means for which unique parameters for each type of thermoplastic resin are recorded; and a calculation means for calculating the melting properties based on the variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions received by the receiving means, and the unique parameters for each type of thermoplastic resin recorded in the recording means.

Description

[Technical Field]

[0001] More specifically, the present invention relates to a melting property calculation apparatus, a melting property calculation method, a computer program, a method for improving molding defects in a resin molded article, and a resin molded article and a method for manufacturing a resin molded article using the same. [Background technology]

[0002] Thermoplastic resins are lightweight and possess excellent mechanical properties and cost-effectiveness, making them widely used as raw materials for various packaging containers such as films, cups, and bottles, as well as for information and electronic materials, automotive parts, tools, toys, and other resin molded products. Furthermore, in applications where thermoplastic resins alone lack sufficient physical properties (strength, barrier properties, adhesiveness, etc.), they are used as raw materials for resin molded articles by blending at least one type of thermoplastic resin (see, for example, Patent Documents 1-3), or as multilayer structures (multilayer films, etc.) formed by laminating at least one type of thermoplastic resin (see, for example, Patent Document 4).

[0003] However, when conventional thermoplastic resins (see, for example, Patent Documents 1 to 3) are melt-molded into the aforementioned resin molded body, unstable flow such as melt fracture and draw resonance can occur depending on the conditions, resulting in various molding defects such as dimensional defects, strength defects, shape defects, and appearance defects. In particular, when melt-molding a multilayer structure (see, for example, Patent Document 4) made by laminating at least one type of thermoplastic resin, in addition to the molding defects caused by the unstable flow described above, there is a problem that molding defects can occur due to the compatibility between adjacent thermoplastic resin layers.

[0004] To address these challenges, Patent Document 5 discloses a technique for blending a fluorine-based elastomer with a thermoplastic resin. Furthermore, Patent Document 6 discloses a method for manufacturing laminated sheets by appropriately changing the type, number of layers, and thickness of the layers using an apparatus that employs a main passage with a shape that reduces the dimensions of each layered resin flow in a direction perpendicular to the interface between the resin flows in the layers forming the composite flow, and increases the dimensions of the layered resin flows in a direction transverse to the composite flow and parallel to the interface between the layered resin flows.

[0005] Furthermore, it is known that the melt-molding properties of thermoplastic resins depend greatly on the viscoelasticity of the molten thermoplastic resin, as well as the molding conditions (e.g., molding die shape, temperature, extrusion rate, etc.). As a method for simulating the flow behavior when melt-molding thermoplastic resins, constitutive equations for calculating the viscoelasticity of the molten thermoplastic resin (see, for example, Non-Patent Documents 1 and 2) and methods for simulating the flow behavior of the molten thermoplastic resin using the viscoelasticity values ​​calculated by these constitutive equations (see, for example, Patent Document 7) have been disclosed.

[0006] Furthermore, several commercially available software programs for simulating the flow behavior during melt molding of thermoplastic resins include POLYCAD2-D (Polydynamics, Inc.), 2D FEM (Compuplast), 3D FEM (Compuplast), SUNDYBASIC (CYBERNET SYSTEMS CO., LTD), SUNDYXTRUD (CYBERNET SYSTEMS CO., LTD), Polyflow (Fluent Inc.), FIDAP (Fluent Inc.), and Fluent (Fluent Inc.). Furthermore, thanks to the dramatic advancements in computer technology in recent years, it has become common practice to utilize commercially available software as described above to optimize molding equipment, molds, resin types, production volumes, operating conditions, molding conditions, etc., for the stable production of the resin molded articles and multilayer structures. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 10-168248 [Patent Document 2] Japanese Patent Publication No. 2007-100110 [Patent Document 3] Patent No. 6549862 [Patent Document 4] Japanese Patent Publication No. 2012-71491 [Patent Document 5] Japanese Patent Publication No. 2009-155357 [Patent Document 6] Patent Application No. 1977-57756 [Patent Document 7] Japanese Patent Publication No. 2019-089229 [Non-patent literature]

[0008] [Non-Patent Document 1] Graessley, WW, Adv. Polym. Sci., 16, 1, (1974) [Non-Patent Document 2] Baird, DG, J. Non-Newtonian Fluid Mech., 148, 13, (2008) [Overview of the project] [Problems that the invention aims to solve]

[0009] In recent years, market needs have become more diverse and sophisticated due to the spread of internet shopping, economic growth in developing countries, and growing environmental awareness. Furthermore, price competition has intensified due to technological innovation and rationalization of production technology. Consequently, the required quality for resin molded products using thermoplastic resins has become more diverse and sophisticated, and there is a growing demand for superior economic efficiency. However, with the aforementioned conventional technologies, it has been difficult to improve various molding defects with sufficient precision, and there have also been economic challenges such as increased raw material costs and the need for high-priced equipment investment, leaving much room for improvement.

[0010] Furthermore, with the aforementioned conventional technology, it is necessary to calculate various melt properties required to improve various molding defects (dimensional defects, strength defects, shape defects, appearance defects, etc.) of the thermoplastic resin molded articles multiple times for each molding condition (temperature, resin type, etc.), so there was still room for improvement in work efficiency.

[0011] Furthermore, since the thermoplastic resin molten material used in the aforementioned resin molded article typically exhibits viscoelasticity during melt molding, it is desirable to consider both the viscosity and elasticity of the thermoplastic resin molten material when simulating the flow behavior of the thermoplastic resin during melt molding. However, when simulating the flow behavior of the thermoplastic resin during melt molding while considering the viscoelasticity of the thermoplastic resin molten material using the aforementioned commercially available software, although the accuracy of the calculation results is relatively high, there is a problem in that the computational load is high and it takes a long time to obtain the calculation results. To address this problem, it is common practice to minimize the computational load and calculation time by assuming the thermoplastic resin molten material is a purely viscous non-Newtonian fluid (without considering the effect of elasticity) when simulating the flow behavior of the thermoplastic resin during melt molding using the aforementioned commercially available software, but there was room for improvement in the accuracy of the calculation results.

[0012] Furthermore, while the aforementioned conventional commercially available simulation software can simulate the flow behavior of thermoplastic resin during melt molding of the resin molded body, it cannot predict the occurrence of the various molding defects themselves. Therefore, there was a need to establish new methods for improving these various molding defects.

[0013] The present invention has been made in view of such circumstances, and it is possible to simultaneously obtain the melt physical properties necessary for improving various molding defects (dimension defects, strength defects, shape defects, appearance defects, etc.) of a resin molded body of at least one or more thermoplastic resins under a plurality of conditions (temperature, resin type, etc.). An object of the present invention is to provide a melt physical property calculation device, a melt physical property calculation method, a computer program, a method for improving molding defects of a resin molded body, a method for improving molding defects of a resin molded body using these, a resin molded body using these, and a method for manufacturing a resin molded body.

Means for Solving the Problems

[0014] The present inventor has intensively studied to solve the above problems. In the process of this study, the intrinsic parameters (shift factor a T , activation energy E a , relaxation time τ i of relaxation elastic modulus G i [Pa], constants R, a, b, etc.) of at least one or more thermoplastic resins used as materials for forming a resin molded body, and variables or arbitrary constants related to molding conditions (angular frequency [rad / s], shear strain rate γ-dot [1 / s] (a symbol with a dot (·) above γ; hereinafter simply referred to as "γ-dot"), elongation strain rate ε-dot [1 / s] (a symbol with a dot (·) above ε; hereinafter simply referred to as "ε-dot"), temperature T [°C], etc.). Based on these, the melt physical properties of the thermoplastic resin are: (A) storage elastic modulus G' [Pa], (B) loss elastic modulus G" [Pa], (C) complex viscosity |η * | [Pa s], (D) shear stress σ s [Pa], (E) shear viscosity η s [Pa s], (F) first normal stress difference N1 [Pa], (G) elongation stress σ e [Pa], (H) elongation viscosity η eWe considered using a melting property calculation device that can simultaneously calculate at least one melting property selected from [Pa s] under multiple conditions (temperature, resin type, etc.). We found that by using the intrinsic parameters of the thermoplastic resin and variables related to the molding conditions, it is possible to simultaneously calculate not only the melting properties (A) to (F) related to the extrusion molding process in which the thermoplastic resin is melted and extruded, but also the melting properties (G) and (H) related to processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping, under multiple conditions (temperature, resin type, etc.), and that molding defects in resin molded articles can be improved in a shorter time and with higher accuracy than before, leading to the present invention.

[0015] In other words, in order to achieve the above-mentioned objectives, the present invention is summarized in the following [1] to

[16] . [1] A melting property calculation device for calculating melting properties when forming a resin molded article containing at least one type of thermoplastic resin, comprising: a receiving means for receiving at least one variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions; a recording means for which specific parameters for each type of thermoplastic resin are recorded; and a calculation means for calculating at least one melting property selected from (A) to (H) below based on the variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions received by the receiving means and the specific parameters for each type of thermoplastic resin recorded in the recording means. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G” [Pa] (C) Complex viscosity |η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N1 [Pa] (G) Elongation stress σ e [Pa] (H) Extensional viscosity η e [Pa s] [2] The melt property calculation apparatus according to [1], wherein the resin molded article is a multilayer structure having two or more thermoplastic resin layers made of a resin composition containing at least one thermoplastic resin. [3] The melt property calculation apparatus according to [1] or [2], wherein the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin that does not contain polar groups, a polyolefin resin that contains polar groups, an ethylene-vinyl alcohol resin, and a polyamide resin. [4] A method for calculating melt properties when forming a resin molded article containing at least one type of thermoplastic resin, using a melt property calculation apparatus described in any of [1] to [3], the method comprising a step of calculating at least one type of melt property selected from (A) to (H) below, based on the type of thermoplastic resin, at least one variable or arbitrary constant relating to molding conditions, and specific parameters for each type of thermoplastic resin. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G” [Pa] (C) Complex viscosity |η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N1 [Pa] (G) Elongation stress σ e [Pa] (H) Extensional viscosity η e [Pa s] [5] The method for calculating melt properties according to [4], wherein the resin molded article is a multilayer structure having two or more thermoplastic resin layers made of at least one type of thermoplastic resin. [6] The method for calculating melt properties according to [4] or [5], wherein the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin that does not contain polar groups, a polyolefin resin that contains polar groups, an ethylene-vinyl alcohol resin, and a polyamide resin. [7] A computer program for calculating melt properties when forming a resin molded article containing at least one type of thermoplastic resin, using a melt property calculation device described in any of [1] to [3], wherein the computer program causes the melt property calculation device to perform the following steps: inputting at least one variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions into the melt property calculation device, thereby obtaining the intrinsic parameters of the input type of thermoplastic resin from the intrinsic parameters for each type of thermoplastic resin recorded in the melt property calculation device in advance; and causing the melt property calculation device to calculate at least one melt property selected from (A) to (H) below based on the obtained intrinsic parameters of at least one type of thermoplastic resin and the variables or arbitrary constant relating to molding conditions. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G” [Pa] (C) Complex viscosity |η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N1 [Pa] (G) Elongation stress σ e [Pa] (H) Extensional viscosity η e [Pa s] [8] The computer program according to [7], wherein the resin molded article is a multilayer structure having two or more thermoplastic resin layers containing at least one type of thermoplastic resin. [9] The computer program according to [7] or [8], wherein the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin that does not contain polar groups, a polyolefin resin that contains polar groups, an ethylene-vinyl alcohol resin, and a polyamide resin.

[10] A method for improving molding defects in a resin molded article, which uses a melt property calculation device described in any of [1] to [3] to improve molding defects in a resin molded article. A method for improving molding defects in a resin molded article, which improves molding defects in a resin molded article using the molten physical property calculation method described in any of

[11] [4] to [6]. A method for improving molding defects in a resin molded body, which involves using a computer program described in any of

[12] [7] to [9] to improve molding defects in a resin molded body.

[13] A method for improving molding defects in a resin molded article, according to any one of

[10] to

[12] , wherein the method for improving molding defects in a resin molded article satisfies all of the following conditions. [conditions] (D) Shear stress σ at the wall surface of the molded die lip of a molten thermoplastic resin s (E) Shear viscosity η s The pressure is 30-3,000,000 Pas, and the (F) first normal stress difference N1 is 100-2,000,000 Pa. (G) tensile stress σ in the sharp contraction section immediately before the molding die lip of the molten thermoplastic resin e (H) Extensional viscosity η e This ranges from 90 to 9,000,000 Pa s.

[14] The resin molded article is a multilayer structure in which a polyolefin resin layer (d) that does not contain polar groups is laminated on at least one side of an ethylene-vinyl alcohol resin layer (a) and / or a polyamide layer (c) via a polyolefin resin layer (b) that contains polar groups, The molding defect improvement method is such that the position of the lamination interface (A / B) between the ethylene-vinyl alcohol resin layer (A) closest to the molded die lip wall surface and the polyolefin resin layer (B) containing polar groups, and / or the position of the lamination interface (C / B) between the polyamide layer (C) and the polyolefin resin layer (B) containing polar groups, satisfies the following formula (22), and the shear strain rate is 1S at the molding temperature of the multilayer structure of the ethylene-vinyl alcohol resin layer (A) and / or the polyamide layer (C) and the polyolefin resin layer (D) that does not contain polar groups. -1 (E) Shear viscosity η s , and extensional strain rate 1S -1 (H) Extensional viscosity η eHowever, a molding defect improvement method described in any of

[10] to

[13] that satisfies the following formula (23). 0.2 ≤ {(distance from the molded die lip wall of the laminate interface (A / B) and / or the laminate interface (C / B)) / (thickness of the molded die lip)} ≤ 0.8 ···(22) 0.5 ≤ {(η e / η s )E / (η e / η s )A}≦4.5 and / or 0.5≦{(η e / η s )E / (η e / η s )U}≦4.5···(23) A resin molded article obtained using a molten physical property calculation apparatus, molten physical property calculation method, computer program, or method for improving molding defects of a resin molded article, as described in any of [1] to

[14] .

[16] A method for manufacturing a resin molded article of a thermoplastic resin, comprising using a melt property calculation apparatus, a melt property calculation method, a computer program, and a molding defect improvement method described in any of [1] to

[14] . [Effects of the Invention]

[0016] By using the melt property calculation apparatus, melt property calculation method, and computer program of the present invention, various melt properties necessary for improving molding defects (dimensional defects, strength defects, shape defects, appearance defects, etc.) of resin molded articles made of at least one type of thermoplastic resin can be simultaneously determined under multiple conditions (multiple molding conditions, multiple types of thermoplastic resins, etc.). As a result, it becomes possible to provide resin molded articles with superior dimensional accuracy, strength, appearance, etc., in a shorter time than conventional methods. [Brief explanation of the drawing]

[0017] [Figure 1] This figure shows an example of the structure of a resin molded product. [Figure 2] This figure shows an example of the structure of another resin molded product. [Figure 3] This is a block diagram that functionally illustrates the configuration of the molten physical property calculation device according to the embodiment. [Figure 4] This flowchart shows the process of calculating the dependence of at least one melt property selected from the melt properties (A) to (H) of a thermoplastic resin on angular frequency ω, shear strain rate γ-dot, and extensional strain rate ε-dot, using the melt property calculation apparatus according to the embodiment. [Figure 5] This flowchart shows the process of calculating the dependence of at least one melt property selected from the melt properties (A) to (H) of a thermoplastic resin and its temperature, using the melt property calculation apparatus according to the embodiment. [Figure 6] This graph shows the calculation results of the (A) storage modulus G' for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 7] This graph shows the calculation results of the (B) loss modulus G'' of ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 8] This graph shows the calculation results of the complex viscosity |η*| (C) of ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 9]This graph shows the calculation results of (D) shear stress σs for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 10] This graph shows the calculation results of the (E) shear viscosity ηs for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 11] This graph shows the calculation results of the (F) first normal stress difference N1 for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 12] This graph shows the calculation results of the (G) tensile stress σe for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Figure 13]This graph shows the calculation results of the (H) extensional viscosity ηe for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to the embodiment. [Modes for carrying out the invention]

[0018] In this specification, when "X~Y" (where X and Y are any numbers) is used, unless otherwise specified, it means "greater than or equal to X and less than or equal to Y," and also includes the meanings of "preferably greater than X" or "preferably less than Y." In this specification, when we use the expressions "X or greater" (where X is any number) or "Y or less" (where Y is any number), we also mean "preferably greater than X" or "preferably less than Y." In this specification, "x and / or y (where x, y are any configuration)" means at least one of x and y, and can mean x only, y only, or x and y. In this specification, the numerical ranges described in stages may be arbitrarily combined with the upper or lower limits of the numerical ranges in any stage. Furthermore, in the numerical ranges described herein, the upper or lower limits may be replaced with the values ​​shown in the examples. In this specification, "main component" means a component that has a significant effect on the properties of the object, and the content of the component is usually 50% by mass or more in the object, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and may be 100% by mass. In this specification, "film" includes "tape" and "sheet." The present invention will be described in detail below, but these are merely examples of preferred embodiments.

[0019] The resin molded articles covered by the present invention, which include at least one thermoplastic resin, are not particularly limited and include, for example, packaging materials, parts, tools, toys, pellets, etc. Furthermore, it is preferable that the resin molded articles have a thermoplastic resin as their main component.

[0020] The resin molded article may be, for example, a resin molded article 1 made only of a first thermoplastic resin 2 as shown in Figure 1, or a resin molded article 1 made of two or more thermoplastic resins, such as the first thermoplastic resin 2 and other thermoplastic resins (for example, a second thermoplastic resin 3, a third thermoplastic resin 4). Furthermore, the resin molded article may be a resin molded article 1 having at least two thermoplastic resin layers made of at least one type of thermoplastic resin, as shown in Figure 2. For example, the resin molded article 1 shown in Figure 2 is formed as a five-layer multilayer structure consisting of a first thermoplastic resin layer 5 which is the outermost layer, a second thermoplastic resin layer 6 adjacent to it, and a third thermoplastic resin layer 7 adjacent to it.

[0021] The thermoplastic resin is not particularly limited and includes, for example, polyolefin resins that do not contain polar groups, polyolefin resins containing polar groups, ionomers, polyvinyl alcohol resins, ethylene-vinyl alcohol resins (hereinafter referred to as "EVOH"), ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, polyester resins, polyamide resins (including copolymerized polyamides), polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, halogenated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, aromatic or aliphatic polyketones, etc. These may be used alone or in combination of two or more.

[0022] Of these, from the viewpoint of practicality and economy, acrylic resins, polystyrene resins, vinyl ester resins, polyolefin resins that do not contain polar groups, polyolefin resins that contain polar groups, EVOH, polyamide resins, acrylic resins, polystyrene resins, and vinyl ester resins are preferred, more preferably polyolefin resins that do not contain polar groups, polyolefin resins that contain polar groups, EVOH, and polyamide resins, particularly preferably polyolefin resins that do not contain polar groups, polyolefin resins that contain polar groups, and EVOH, and especially preferably EVOH. These may be used alone or in combination of two or more.

[0023] [Polyolefin resins that do not contain polar groups] Examples of polyolefin resins that do not contain the aforementioned polar groups include polyethylene resins such as linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene (block and random) copolymers, and ethylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers; polypropylene resins such as polypropylene and propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers; polybutene, polypentene, and polycyclic olefin resins (polymers having a cyclic olefin structure in at least one of the main chain and side chains).

[0024] Furthermore, the ethylene and α-olefins in the polyolefin resin may be plant-derived ethylene and α-olefins derived from bioethanol, or non-plant-derived ethylene and α-olefins, i.e., petroleum-derived ethylene and α-olefins, and both may be used in combination. Since a wide variety of petroleum-derived α-olefins are available, the physical properties of the polyolefin resin can be easily adjusted by using them in the manufacturing process. By using plant-derived ethylene and α-olefins, the biomass content of the final product can be further increased, and the environmental burden can be reduced.

[0025] As a method for producing the aforementioned plant-derived ethylene and α-olefins, conventional methods are used to produce bioethanol by fermenting sugar solutions or starches obtained from plants such as sugarcane, corn, and sweet potatoes with microorganisms such as yeast. This bioethanol is then heated in the presence of a catalyst, and plant-derived ethylene and α-olefins (1-butene, 1-hexene, etc.) can be obtained through intramolecular dehydration reactions. Furthermore, plant-derived polyethylene resins can be produced using the obtained plant-derived ethylene and α-olefins in a manner similar to that used for producing petroleum-derived polyethylene resins.

[0026] Methods for producing the aforementioned plant-derived ethylene, α-olefin, and plant-derived polyethylene resins are described in detail, for example, in Japanese Patent Publication No. 2011-506628. Examples of plant-derived polyethylene resins suitably used in the present invention include Green PE manufactured by Braskem SA.

[0027] The melt flow rate (MFR) (230°C, 2160g load) of the polyolefin resin that does not contain the aforementioned polar groups is typically 0.1 to 100 g / 10 min, preferably 0.5 to 50 g / 10 min.

[0028] [Polyolefin resins containing polar groups] Examples of polyolefin resins containing the aforementioned polar groups include modified polyolefin resins containing carboxyl groups or acid anhydride groups, obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to a polyolefin resin that does not contain the aforementioned polar groups through addition reactions, graft reactions, or the like.

[0029] Examples of the unsaturated carboxylic acid include unsaturated dicarboxylic acids and unsaturated carboxylic acid anhydrides. Examples of the unsaturated dicarboxylic acids include maleic acid, fumaric acid, chloromaleic acid, hymic acid, citraconic acid, and itaconic acid, while examples of the unsaturated monocarboxylic acids include acrylic acid, butanoic acid, crotonic acid, vinylacetic acid, methacrylic acid, pentenoic acid, dodecenoic acid, linoleic acid, angelic acid, and cinnamic acid. Examples of the unsaturated carboxylic acid anhydrides include the acid anhydrides of the unsaturated dicarboxylic acids or unsaturated monocarboxylic acids. Specifically, examples include maleic anhydride, hymic anhydride, itaconic anhydride, citraconic anhydride, and acrylic acid anhydride. Two or more of the unsaturated carboxylic acids may be used in combination. Of these, maleic anhydride is preferred from the viewpoint of recyclability and economic efficiency.

[0030] The content of the unsaturated carboxylic acid is typically 0.001 to 3% by mass, preferably 0.01 to 1% by mass, and particularly preferably 0.03 to 0.5% by mass, relative to the polyolefin resin containing polar groups. If the content (modification amount) of unsaturated carboxylic acid is low, adhesion tends to decrease, while if it is high, crosslinking reactions occur, and moldability tends to decrease.

[0031] The acid value of the polyolefin resin containing the polar group is typically 0.01 to 120 mgKOH / g, preferably 0.5 to 10 mgKOH / g, more preferably 0.5 to 7 mgKOH / g, even more preferably 0.5 to 5 mgKOH / g, and particularly preferably 0.5 to 3 mgKOH / g. If the acid value of the polyolefin resin containing the polar group is too low, the mechanical strength of the resulting molded article tends to decrease. Conversely, if the acid value of the polyolefin resin containing the polar group is too high, the fluidity of the resin composition deteriorates, and the layer thickness of the resulting resin molded article tends to become uneven. When the polyolefin resin containing the polar group is a mixture of multiple types of resins, the acid value of the polyolefin resin containing the polar group is determined by the weighted average of the acid values ​​of each resin according to the mixing mass ratio.

[0032] Furthermore, when using a polyolefin resin containing polar groups in combination with a polyolefin resin not containing polar groups, it is preferable that the polyolefin resin containing polar groups is an acid-modified version of the same type of polyolefin resin as the polyolefin resin not containing polar groups, from the viewpoint of excellent compatibility with the polyolefin resin not containing polar groups. For example, if the polyolefin resin not containing polar groups is polypropylene, it is preferable that the polyolefin resin containing polar groups is acid-modified polypropylene, and if the polyolefin resin not containing polar groups is polyethylene, it is preferable that the polyolefin resin containing polar groups is acid-modified polyethylene.

[0033] When a polyolefin resin containing the aforementioned polar group is used, the molding defects of the resin molded article tend to improve. The reason for this effect is not clear, but it is presumed that when manufacturing a resin molded article consisting of at least one thermoplastic resin, using a polyolefin resin containing a polar group refines the dispersion size of the mixture of thermoplastic resins other than the polyolefin resin containing the polar group and EVOH and / or polyamide resins, making the flow behavior during melt molding of the resin molded article more stable, and as a result the molding defects improve.

[0034] Furthermore, the MFR (melt flow rate, 190°C, under a 2.16 kg load) of polyolefin resins containing polar groups is typically 0.01 to 1000 g / 10 min, preferably 0.05 to 800 g / 10 min, particularly preferably 0.1 to 200 g / 10 min, and especially preferably 0.5 to 50 g / 10 min. Having the MFR of polyolefin resins containing polar groups within this range tends to further improve the mechanical strength of the molded resin article.

[0035] [EVOH] The aforementioned EVOH is a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is typically obtained by copolymerizing ethylene with a vinyl ester monomer. It is a water-insoluble thermoplastic resin known as an ethylene-vinyl alcohol copolymer or ethylene-vinyl ester copolymer saponified. Any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization, can be used, but generally, solution polymerization using methanol as the solvent is used. The saponification of the obtained ethylene-vinyl ester copolymer can also be carried out by known methods.

[0036] In other words, the EVOH mainly consists of ethylene structural units and vinyl alcohol structural units, and contains a small amount of vinyl ester structural units that remain unsaponified.

[0037] As the vinyl ester monomer, vinyl acetate is typically used due to its availability from the market and efficient impurity treatment during manufacturing. Other vinyl ester monomers include, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate, and aromatic vinyl esters such as vinyl benzoate. Among these, aliphatic vinyl esters having 3 to 20 carbon atoms are preferred, more preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. These are usually used individually, but multiple types may be used simultaneously as needed.

[0038] Furthermore, the EVOH may also contain structural units derived from the following comonomers, in addition to ethylene structural units and vinyl alcohol structural units (including unsaponified vinyl ester structural units). Examples of the aforementioned comonomers include α-olefins such as propylene, isobutene, α-octene, α-dodecene, and α-octadecene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 3-buten-1,2-diol, and hydroxyl group-containing α-olefin derivatives such as their esters and acylated products; hydroxymethylvinylidene diacetates such as 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyronyloxy-2-methylenepropane; unsaturated carboxylic acids or their salts, partially alkyl esters, fully alkyl esters, nitriles, amides, or anhydrides; unsaturated sulfonic acids or their salts; vinylsilane compounds; vinyl chloride; styrene, etc.

[0039] Furthermore, as the EVOH, "post-modified" EVOH such as urethane, acetal, cyanoethylated, or oxyalkyleneated can also be used.

[0040] Among the modified EVOHs described above, EVOHs in which primary hydroxyl groups have been introduced into the side chains by copolymerization are preferred because they have good secondary moldability in processes such as stretching and vacuum / pressure forming, and in particular, EVOH having a 1,2-diol structure in the side chains is preferred.

[0041] The ethylene structural unit content in the aforementioned EVOH is measured according to ISO 14663 and is typically 20 to 60 mol%, preferably 25 to 50 mol%, and particularly preferably 25 to 35 mol%. If the content is too low, the gas barrier properties and melt moldability at high humidity will decrease, while if it is too high, the gas barrier properties will decrease.

[0042] The degree of saponification of EVOH is measured according to JIS K6726 (where EVOH is a solution uniformly dissolved in water / methanol solvent) and is typically 90-100 mol%, preferably 95-100 mol%, and particularly preferably 99-100 mol%. If the degree of saponification is too low, gas barrier properties, thermal stability, moisture resistance, etc. tend to decrease.

[0043] Furthermore, the melt flow rate (MFR) of the EVOH (at 210°C and a load of 2160g) is typically 0.5 to 100g / 10min, preferably 1 to 50g / 10min, and particularly preferably 3 to 35g / 10min. If the MFR is too high, film formation tends to decrease. Conversely, if the MFR is too low, melt extrusion tends to become difficult.

[0044] Furthermore, the EVOH may be a mixture of other EVOHs, and examples of such other EVOHs include those with different ethylene content, different degrees of saponification, different melt flow rates (MFRs), different other copolymer components, and different modification levels (for example, those with different content of structural units containing primary hydroxyl groups in the side chains).

[0045] The EVOH content is 0.1 to 25% by mass, preferably 0.3 to 20% by mass, and more preferably 0.5 to 15% by mass, relative to the resin molded article, in order to obtain excellent mechanical strength. If the EVOH content is too low, the gas barrier properties of the resin molded article will be insufficient, and if the content is too high, the mechanical strength of the resin molded article will be insufficient.

[0046] [Polyamide resin] Known polyamide resins can be used as the aforementioned polyamide resins. For example, homopolymers such as polycapramid (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), and polylauryl lactam (nylon 12) can be used. Also, copolymer polyamide resins include polyethylenediamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sevacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), and caprolactam. / Lauryl lactam copolymer (Nylon 6 / 12), Caprolactam / ω-aminononanoic acid copolymer (Nylon 6 / 9), Caprolactam / hexamethylenediammonium adipate copolymer (Nylon 6 / 66), Lauryl lactam / hexamethylenediammonium adipate copolymer (Nylon 12 / 66), Ethylenediamine adipamide / hexamethylenediammonium adipate copolymer (Nylon 26 / 66), Examples include aliphatic polyamides such as caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon 66 / 610) and ethyleneammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon 6 / 66 / 610), aromatic polyamides such as polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, polymetaxylylene adipamide, hexamethylene isophthalamide / terephthalamide copolymer, poly-P-phenylene terephthalamide, and poly-P-phenylene·3-4'-diphenyl ether terephthalamide, amorphous polyamides, and these polyamide resins modified with aromatic amines such as methylenebenzylamine and metaxylylenediamine, or metaxylylenediammonium adipate. Alternatively, these may be end-modified polyamide resins, and end-modified polyamide resins are preferred.

[0047] Furthermore, the resin molded article may contain other additives commonly blended with thermoplastic resins, within a range that does not impair the effects of the present invention (for example, usually 30% by mass or less, preferably 10% by mass or less of the resin molded article), such as heat stabilizers, inorganic fillers (for example, hydrotalcite compounds, mica, talc, calcium carbonate, titanium dioxide, kaolin, clay, glass flakes, glass beads, vermiculite, smectite, etc.), antioxidants, antistatic agents, colorants, and UV absorbers. Lubricants (e.g., aliphatic carboxylic acids (e.g., acetic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, 12-hydroxystearic acid, arachidic acid, henicosyl acid, behenic acid, lignoceric acid, montanic acid, melissic acid, tartaric acid, glyceric acid, hydroxybutyric acid, malic acid, tartaric acid, gluconic acid, mevalonic acid, pantoin) Unsaturated aliphatic monocarboxylic acids such as acids, linoleic acid, linolenic acid, pinolenic acid, eleostearic acid, isostearic acid, isononanoic acid, 2-ethylhexanoic acid, 2-heptylundecanoic acid, 2-octyldodecanoic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, gadrenic acid, eicosenoic acid, erucic acid, nervonic acid, ricinoleic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, ce Saturated aliphatic dicarboxylic acids such as bacitic acid, unsaturated aliphatic dicarboxylic acids such as eicosadienoic acid and docosadienoic acid, saturated aliphatic tricarboxylic acids such as citric acid, isocitric acid and aconitic acid, etc., metal salts of the aliphatic carboxylic acids (metal species include, for example, alkali metals such as lithium, sodium and potassium, alkaline earth metals such as beryllium, magnesium, calcium and barium, and transition metals such as chromium, cobalt, nickel, copper, iron and zinc, etc.), higher fatty acid esters (methyl esters, isopropyl esters, butyl esters, octyl esters of higher fatty acids, etc.), higher fatty acid amides (Saturated aliphatic amides such as stearic acid amide and behenic acid amide, unsaturated fatty acid amides such as oleic acid amide and erucic acid amide, bis-fatty acid amides such as ethylenebis-stearic acid amide, ethylenebis-oleic acid amide, ethylene-bis-erucic acid amide, and ethylene-bis-lauric acid amide), low molecular weight polyolefins ( For example, it may contain known additives such as low molecular weight polyethylene or low molecular weight polypropylene (for example, with a molecular weight of about 500 to 10000), fluoroethylene resin, plasticizers (for example, ethylene glycol, glycerin, aliphatic polyhydric alcohols such as hexanediol), light stabilizers, surfactants, antibacterial agents, desiccants, antiblocking agents, flame retardants, crosslinking agents, foaming agents, nucleating agents, antifogging agents, biodegradable additives, silane coupling agents, oxygen absorbers, phosphoric acid and / or its salts, cinnamic acid and / or its salts, conjugated polyene compounds, enediol group-containing substances (for example, phenols such as propyl gallate), aldehyde compounds (for example, unsaturated aldehydes such as crotonaldehyde), etc. These can be used alone or in combination of two or more.

[0048] <Frozen Material Properties Calculation Device> The melt property calculation device for calculating the melt properties when molding a resin molded article containing at least one type of thermoplastic resin according to this embodiment comprises: a receiving means that receives at least one variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions; a recording means that records specific parameters for each type of thermoplastic resin; and a calculation means that calculates at least one melt property selected from (A) to (H) below based on the variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions received by the receiving means and the specific parameters for each type of thermoplastic resin recorded in the recording means. The following will be described in detail with reference to the drawings illustrating this embodiment. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G” [Pa] (C) Complex viscosity |η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N1 [Pa] (G) Elongation stress σ e [Pa] (H) Extensional viscosity η e [Pa s]

[0049] Figure 3 is a block diagram functionally showing the configuration of a melt property calculation device for calculating the melt properties of a resin molded article made of at least one thermoplastic resin according to this embodiment.

[0050] Figure 3(I) shows a melt property calculation device according to this embodiment using a general-purpose computer. The molten material property calculation device (I) includes a CPU (II) that controls the entire device, an auxiliary storage means (III) such as a CD-ROM drive that reads various information from a recording medium REC such as a CD-ROM that stores various information such as the computer program PG and data for the molten material property calculation device according to this embodiment, a recording means (IV) such as a hard disk that stores the computer program PG and various information such as data read by the auxiliary storage means (III), and RAM (V) that temporarily stores information used for various processes. Furthermore, the various information recorded in the recording means (IV) includes various formulas and constants used in the calculation of molten physical properties, which will be described later. In addition, the molten physical property calculation device (I) may be equipped with input means (VI) such as a sensor for detecting values ​​such as temperature, a mouse, and a keyboard, and output means (VII) such as a monitor and a printer.

[0051] The CPU(II) controls the molten material property calculation device(I), is composed of known components, and executes the molten material property calculation program described later.

[0052] The auxiliary storage means (III) can be a commonly available CD, DVD, BD, memory card, USB memory, online storage, etc.

[0053] The recording means (IV) can use an electromagnetic recording medium, specifically, a hard disk drive (HDD) or a solid-state drive (SSD). The recording means (IV) stores a database containing unique parameters for each type of thermoplastic resin, as well as various formulas and constants used to calculate melt properties. The database may also be stored in the auxiliary storage means (III) and read from there when executing the melt property calculation program (the computer program according to this embodiment).

[0054] The RAM(V) is the operating area of ​​the melt property calculation program, and can use commonly available DRAM, specifically, SDRAM or DDR SDRAM.

[0055] The input means (VI) can be any commonly available input device, specifically, for example, a keyboard, touchpad, mouse, sensor, microphone, etc.

[0056] The output means (VII) can be a commonly available information output device, specifically a monitor or a printer.

[0057] The melt property calculation device (I) includes a receiving means that receives at least one variable or arbitrary constant relating to one or more types of thermoplastic resins and molding conditions input by an input means (VI), a recording means in which unique parameters for each type of thermoplastic resin are recorded, and a CPU (II) that executes various procedures included in the computer program PG included in the computer program PG based on the information of the thermoplastic resin received by the receiving means, reads various information such as the computer program PG according to this embodiment and data such as unique parameters for each type of thermoplastic resin from the recording means (IV), stores it in RAM (V), and calculates the melt property when forming a resin molded article containing at least one type of thermoplastic resin.

[0058] The melt properties calculated by the computer program PG of the melt property calculation device (I) based on the type of thermoplastic resin, variables (numerical range) related to molding conditions, or arbitrary constants and intrinsic parameters include at least one of the following (A) to (H). (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G” [Pa] (C) Complex viscosity |η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N1 [Pa] (G) Elongation stress σ e [Pa] (H) Extensional viscosity η e [Pa s] Furthermore, the calculated molten material properties are obtained as a graph where, if one of the variables selected from angular frequency ω, shear strain rate γ-dot, and extensional strain rate ε-dot, or temperature T, is input as a variable related to the molding conditions, the X-axis (horizontal axis) is plotted with one of the variables selected from angular frequency ω, shear strain rate γ-dot, and extensional strain rate ε-dot, or temperature T, and the Y-axis (vertical axis) is plotted with one of the variables selected from (A) to (H) above [see, for example, (a) and (b) in Figures 6 to 13]. In addition, if one of the variables selected from angular frequency ω, shear strain rate γ-dot, and extensional strain rate ε-dot, or temperature T, is input as an arbitrary constant related to the molding conditions, the values ​​of (A) to (H) under specific conditions can be calculated [see, for example, (c) and (d) in Figures 6 to 13].

[0059] <Method for calculating molten physical properties, and computer program> Next, the molten physical properties calculation method and computer program according to this embodiment will be described.

[0060] Figure 4 is a flowchart illustrating a method for calculating melt properties using the melt property calculation apparatus (I) of the present invention, in which one of the angular frequency ω, shear strain rate γ-dot, and extensional strain rate ε-dot is assigned to the X axis, and the melt properties (A) to (H) of the thermoplastic resin are assigned to the Y axis. The operator of the melt property calculation device (I) inputs the type of thermoplastic resin and the molding temperature (if two or more types of thermoplastic resins are used, the type and molding temperature for each) to the melt property calculation device (I). Next, the operator specifies one of the following as a variable or arbitrary constant related to the molding conditions: angular frequency ω, shear strain rate γ-dot, and extensional strain rate ε-dot. After that, the operator inputs at least one melt property to be calculated from the melt properties (A) to (H) of the thermoplastic resin. The following explanation will follow this flowchart.

[0061] The melt property calculation device (I) receives input of the type of thermoplastic resin from the input means (VI) (S101) under the control of the CPU (II), which executes a computer program PG stored in RAM (V). The type of thermoplastic resin is entered by selecting from a pre-set list of options. Furthermore, if a thermoplastic resin other than those pre-set is to be used, the specific parameters of the thermoplastic resin can be determined according to the method described later, allowing the input of a thermoplastic resin other than those pre-set.

[0062] Next, the molding temperatures of the thermoplastic resins received above are received from the input means (VI) (S102).

[0063] If you want to calculate one of the following variables as a variable: angular frequency and / or shear strain rate and extensional strain rate, specify the angular frequency (e.g., 0.001 to 10000 rad / s) and shear strain rate (e.g., 0.001 to 10000 s) to be calculated from the input means (VI). -1 ), and extensional strain rate (e.g., 0.001~10000s) -1) accepts designation (S103). On the other hand, when calculating the angular frequency, shear strain rate, and extensional strain rate as arbitrary constants, the system accepts arbitrary constants for the angular frequency, shear strain rate, and extensional strain rate to be calculated from the input means (VI) (S104).

[0064] Next, the system accepts the specification of at least one molten physical property to be calculated from the molten physical properties (A) to (H) (S105).

[0065] Subsequently, under the control of the CPU (II) which executes the computer program PG stored in RAM (V), at least one melt property selected from melt properties (A) to (H) is calculated based on the various information received and the intrinsic parameters of the thermoplastic resin that have been recorded in advance (S106).

[0066] Furthermore, the melt property calculation device (I), under the control of the CPU (II) which executes a computer program PG stored in RAM (V), outputs the melt property calculated in (S106) as a value indicating the melt property of the thermoplastic resin from output means (VII) such as a monitor and printer (S107), and also records the calculation result in the recording means (IV) (S108).

[0067] Figure 5 is a flowchart showing the process of calculating the melt properties (A) to (H) of the thermoplastic resin using the melt property calculation apparatus (I) according to this embodiment, with the temperature T on the X axis and the melt properties (A) to (H) on the Y axis. The operator of the melt property calculation device (I) inputs at least one type of thermoplastic resin to the device (I). Next, the operator specifies the molding temperature (variable or arbitrary constant) of the thermoplastic resin input above. After that, the operator inputs at least one melt property selected from the melt properties (A) to (H) to be calculated for the thermoplastic resin. The following explanation will follow this flowchart.

[0068] In the melt property calculation device (I), the CPU (II), which executes a computer program PG stored in RAM (V), receives input of thermoplastic resin type from the input means (VI) (S201). The type of thermoplastic resin is entered by selecting from a pre-set list of options. Furthermore, if a thermoplastic resin other than those pre-set is to be used, the specific parameters of the thermoplastic resin can be determined according to the method described later, allowing the input of a thermoplastic resin other than those pre-set.

[0069] When calculating using the molding temperature of the thermoplastic resin received as described above as a variable, the input means (VI) accepts the specification of the molding temperature of the thermoplastic resin to be calculated (for example, 150 to 300°C) (S202). Furthermore, if the molding temperature of the thermoplastic resin received as described above is to be calculated as an arbitrary constant, the input means (VI) accepts an arbitrary constant for the molding temperature of the thermoplastic resin to be calculated (S203).

[0070] Next, the system accepts the specification of at least one molten physical property to be calculated, selected from (A) to (H) (S204).

[0071] Subsequently, the CPU (II), which executes the computer program PG stored in RAM (V), calculates at least one melt property selected from melt properties (A) to (H) based on the various information received and the pre-recorded intrinsic parameters of the thermoplastic resin (S205).

[0072] Furthermore, the melt property calculation device (I), under the control of the CPU (II) which executes a computer program PG stored in RAM (V), outputs the melt property calculated in (S205) as a value indicating the melt property of the thermoplastic resin from output means (VII) such as a monitor and printer (S206), and also records the calculation result in the recording means (IV) (S207).

[0073] The above embodiments mainly show a configuration in which the molten physical property calculation device (I) is used alone. However, the present invention is not limited to this, and may be used as a device attached to other equipment such as a modification facility via a sensor as an input means (VI) to support process control, or it may be used as a device connected to a communication network such as the Internet to provide a service for calculating physical properties to a personal computer connected to the communication network. The present invention can be applied to a variety of configurations.

[0074] <Method for calculating molten physical properties (A) to (H)> Next, a method for calculating the melt properties (A) to (H) of a resin molded article made of at least one type of thermoplastic resin using the melt property calculation apparatus (I) according to the embodiment will be described. This method for calculating the melt properties (A) to (H) is usually stored in the recording means (IV) as a computer program PG.

[0075] <Methods for measuring various types of viscoelasticity> To calculate the melt properties (A) to (H) of a thermoplastic resin, the intrinsic parameters of the thermoplastic resin (relaxation time τ) are required. i Relaxation modulus G i , shift factor a T , activation energy E a Constants a and b are required. These intrinsic parameters are determined from dynamic shear viscoelasticity, steady-state shear viscoelasticity, steady-state shear viscoelasticity in the high shear strain rate region, and extensional viscosity. The measurement methods for these various viscoelastic properties are described below.

[0076] [Dynamic shear viscoelasticity measurement] The dynamic shear viscoelasticity can be evaluated using a general rotational rheometer (e.g., Anton Paar MCR305). For example, by performing dynamic shear viscoelasticity measurements under the following evaluation conditions, the storage modulus G'(ω), loss modulus G''(ω), and complex viscosity |η of the thermoplastic resin molten state can be determined. *(ω)| and other parameters can be evaluated. Furthermore, evaluation samples can be prepared using a general-purpose heating press (for example, the "MIC-1867" manual hydraulic vacuum heating press manufactured by Imoto Seisakusho Co., Ltd.). Angular frequency: 10 -2 ~10 2 rad / s Measurement temperature: 180~260℃ Distortion: 5% Measuring jig: 25mm parallel-to-parallel plate Melting time: 10 min Atmosphere: Nitrogen

[0077] [Steady-state shear viscoelasticity measurement] The steady-state shear viscoelasticity can be evaluated using a general rotational rheometer (e.g., MCR305, manufactured by Anton Paar). For example, by performing steady-state shear viscoelasticity measurements under the following evaluation conditions, the shear stress σ of the molten thermoplastic resin can be determined. s (γ-dot), shear viscosity η s The gamma dot (γ-dot), the first normal stress difference N1(γ-dot), etc., can be evaluated. Furthermore, the evaluation samples can be prepared using a general heating press (for example, the manual hydraulic vacuum heating press "MIC-1867" manufactured by Imoto Seisakusho Co., Ltd.). Shear strain rate: 0.1~30S -1 Measurement temperature: 180~260℃ Measuring jig: 25mm cone-parallel plate Jig angle: 0.1 rad Melting time: 10 min Atmosphere: Nitrogen

[0078] [Steady-state shear viscoelasticity measurement in the high shear strain rate region] Furthermore, when evaluating steady-state shear viscoelasticity in a relatively high shear strain rate region compared to the steady-state shear viscoelasticity measurement described above, evaluation can be performed using a general-purpose capillary rheometer (e.g., Gottfert's "RHEOGRAPH 20"). For example, by performing steady-state shear viscoelasticity measurement under the following evaluation conditions, the shear stress σ of the molten thermoplastic resin can be determined.s (γ-dot), shear viscosity η s (γ-dots), etc., can be evaluated in a relatively higher shear strain rate region than described above. Shear strain rate: 10~3000 s -1 Measurement temperature: 180~260℃ Capillary die 1: Length 10mm, diameter 1mm, inlet angle 180° Capillary die 2: Length 0.2mm, diameter 1mm, inlet angle 180° Melting time: 10 min At this time, the true shear strain rate γ-dot can be determined by applying the Rabinowitsch correction (e.g., ISO 11443; Plastics - Determination of the fluidity of plastics using capillary and slit-die rheometers, see Eisenschitz R., Rabinowitsch, B., and Weissenberg, K.: Mitt. Dtsch. Mat.-Prf.-Anst. (Bulletin of German Materials-Testing Institution). Sonderheft. 9, 91, (1929)), and the true shear stress σ can be determined by applying the Baglay correction (e.g., ISO 11443; Plastics - Determination of the fluidity of plastics using capillary and slit-die rheometers, see Bagley EB, J. Appl. Phys. 28, 624, (1957)). s (γ-dot) is obtained by applying the two corrections mentioned above to obtain the true shear viscosity η s (γ-dot) can be determined.

[0079] [Elongational viscosity measurement] The extensional viscosity of the aforementioned thermoplastic resin molten material can be evaluated using a general-purpose capillary rheometer (e.g., Gottfert's "RHEOGRAPH 20"). For example, by measuring the extensional viscosity under the following evaluation conditions, the extensional stress σ of the thermoplastic resin molten material can be determined. e (ε-dot), extensional viscosity η e (ε-dot) and other parameters can be evaluated. Extension strain rate: 1-1000 s -1 Measurement temperature: 180~260℃ Capillary die 1: Length 10mm, diameter 1mm, inlet angle 180° Capillary die 2: Length 0.2mm, diameter 1mm, inlet angle 180° Melting time: 10 min At this time, the tensile stress σ e (ε-dot), extensional viscosity η e The tensile strain rate ε-dot can be calculated using the following equations (1) to (3), proposed by Cogswell (Polymer Engineering Science, Vol. 12, pp. 64-73 (1972)).

[0080]

number

[0081] Here, k is a constant, and the exponent n is the shear rate range in which melt fracture or wall slip does not occur (for example, 100 s). -1 ≤γ-dot ≤1000s -1 shear stress σ in (etc.) sIt can be determined by assuming that (γ-dot) and the shear strain rate γ-dot follow a power law and performing a quadratic function fitting. P0 is the pressure loss that occurs at the capillary die length 0 (zero), and the Baglay correction for measurement results using two or more capillary dies of different lengths (e.g., ISO 11443; Plastics - Determination of the fluidity of plastics using capillary and slit-die rheometers) is used. This can be determined by performing the following (see Bagley EB, J. Appl. Phys. 28, 624, (1957)).

[0082] [Method for determining the intrinsic parameters of thermoplastic resins] Below are the intrinsic parameters of the thermoplastic resin (relaxation time τ) necessary to calculate the melt properties (A) to (H) of the thermoplastic resin from the measured values ​​obtained from the viscoelasticity measurement described above. i Relaxation modulus G i , shift factor a T , activation energy E a We will now explain how to find the constants a and b.

[0083] [relaxation time τ i Relaxation modulus G i How to find it] The storage modulus G'(ω), loss modulus G''(ω), and complex viscosity |η obtained from the aforementioned dynamic shear viscoelasticity measurement. * (ω)|, and / or the shear stress σ obtained from the steady-state shear viscoelasticity measurement. s (γ-dot), shear viscosity η s (γ-dot), from the first normal stress difference N1(γ-dot), the relaxation time τ of the thermoplastic resin molten state. i Relaxation modulus G i It is possible to find this. For example, the storage modulus G'(ω), loss modulus G''(ω), and complex viscosity |η obtained from the dynamic shear viscoelasticity measurement are... *(ω) can be expressed by the following equations (4) to (6) using the Maxwell model (see, for example, Non-Patent Document 6 and Non-Patent Document 7).

[0084] [Number]

[0085] Here, ω is the angular frequency, and G i is the relaxation elastic modulus at the relaxation time τ i . By fitting the curves represented by the above equations (4) to (6) to the measured values of the storage elastic modulus G'(ω), loss elastic modulus G”(ω), and complex viscosity |η * (ω) of the melt of the thermoplastic resin obtained by the dynamic shear viscoelasticity measurement, the relaxation elastic modulus G i at the relaxation time τ i of the thermoplastic resin melt can be obtained.

[0086] [Method for obtaining the shift factor a T , activation energy E a In addition, the shift factor a T and activation energy E a of the thermoplastic resin melt can be obtained, for example, by the following method. The activation energy E a is a numerical value calculated from the shift factor a * when creating a master curve showing the angular frequency (unit: rad / sec) dependence of the complex viscosity |η T (ω) (unit: Pa sec) of the melt of the thermoplastic resin at the reference temperature Tr based on the temperature-time superposition principle, and is a value obtained by the method shown below. First, for a plurality of temperatures including the reference temperature Tr, the complex viscosity-angular frequency curves of the thermoplastic resin melt at each temperature T are obtained. Next, based on the temperature-time superposition principle, each complex viscosity-angular frequency curve is superimposed on the complex viscosity-angular frequency curve of the melt of the thermoplastic resin at the reference temperature Tr to obtain the shift factor a at each temperature TT We will find the following: the respective temperature T and the shift factor a at each temperature. T Therefore, by the least squares method, [lna T ] and [1 / T-1 / T r Next, calculate the linear approximation formula [Equation (7)] for ]. Then, calculate the slope (=E a / R) from activation energy E a We seek.

[0087]

number

[0088] Here, R is the gas constant (= 8.31 J / molK).

[0089] Note that shift factor a T This can also be determined from the amount of shift when the log-log curves of the complex viscosity-angular frequency curves at each temperature T are shifted along the log(Y)=-log(X) axis (where the Y axis is complex viscosity and the X axis is angular frequency) and superimposed on the complex viscosity-angular frequency curve at the reference temperature Tr. In this superposition, the log-log curves of the complex viscosity-angular frequency curves at each temperature T are obtained by shifting the angular frequency to a T Double the molten complex viscosity to 1 / a T Move it twice as far.

[0090] Furthermore, the shift factor a at multiple temperatures, including the reference temperature Tr. T And, [lna] obtained from the measured temperature T. T ] and [1 / T-1 / T r The slope (=E) of the first-order approximation with [Equation (7)] a When calculating the correlation coefficient ( / R) using the least squares method, ensure that the correlation coefficient is 0.99 or higher.

[0091] [How to find constants a and b] The shear stress σ of the molten thermoplastic resin obtained from the steady-state shear viscoelasticity measurement described above. s (γ-dot), shear viscosity η s(γ-dot), and / or the extensional stress σ of the molten thermoplastic resin obtained from the extensional viscosity measurement. e (ε-dot) Extensional viscosity η e The constants a and b of the molten thermoplastic resin can be determined from (ε-dot). For example, the shear viscosity η of a molten thermoplastic resin s Using (γ-dot), the extensional viscosity η of the molten thermoplastic resin obtained from the extensional viscosity measurement is e (ε-dot) is given by equation (8) below. In this case, the tensile strain rate ε-dot and the shear strain rate γ-dot can be considered equivalent.

[0092]

number

[0093] The extensional viscosity η of the molten thermoplastic resin obtained from the extensional viscosity measurement described above. e By selecting constants a and b such that the curve shown in equation (8) overlaps with the measured value of (ε-dot), the constants a and b of the molten thermoplastic resin can be determined.

[0094] The method for determining various intrinsic parameters of the thermoplastic resin can be applied to a single thermoplastic resin, as well as to composite materials made by blending two or more thermoplastic resins.

[0095] <(A) Method for calculating the storage modulus G' [Pa]> A method for calculating the (A) storage modulus G' of a molten thermoplastic resin from various intrinsic parameters of the thermoplastic resin obtained by the above method will be described. The storage modulus G' (A) is a physical property related to the elasticity of a molten thermoplastic resin when subjected to shear deformation, and is a physical property that is mainly involved in melting processes such as extrusion molding, which involves extruding a molten thermoplastic resin, and processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping. Using the aforementioned intrinsic parameters, the storage modulus G' of the thermoplastic resin molten material (A) is given by the following equation (9).

[0096]

number

[0097] By plotting the angular frequency ω or temperature T, which are variables related to the molding conditions, on the X-axis, and the storage modulus G' (A) calculated using equation (9) above, on the Y-axis, the storage modulus G' (A) can be calculated under various conditions (molding conditions, etc.). Furthermore, by selecting a specific angular frequency ω or temperature T, the storage modulus G' (A) under specific conditions (molding conditions, etc.) can be calculated arbitrarily.

[0098] Figure 6 illustrates the calculation results of (A) storage modulus G' for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (A) the storage modulus G' can be determined simultaneously under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), making it possible to provide resin molded articles with superior dimensional accuracy, strength, appearance, etc., in a shorter time than conventional methods.

[0099] <(B) Method for calculating the loss modulus of elasticity G” [Pa]> A method for calculating the (B) loss modulus G'' of a molten thermoplastic resin from various intrinsic parameters of the thermoplastic resin obtained by the above method will be described. (B) The loss modulus G'' is a physical property related to the viscosity of a molten thermoplastic resin when it undergoes shear deformation, and is a molten physical property mainly involved in extrusion molding processes that extrude molten thermoplastic resins, and processes that impart shape to the molten thermoplastic resin, such as film formation / stretching / shaping. Using the aforementioned intrinsic parameters, the (B) loss modulus G'' of the molten thermoplastic resin is given by the following equation (10).

[0100]

number

[0101] By plotting the angular frequency ω or temperature T, which are variables related to the molding conditions, on the X-axis, and the (B) loss modulus G'' calculated by equation (10) on the Y-axis, the (B) loss modulus G'' can be calculated under various conditions (molding conditions, etc.). Furthermore, by selecting a specific angular frequency ω or temperature T, the (B) loss modulus G'' under specific conditions (molding conditions, etc.) can be calculated arbitrarily.

[0102] Figure 7 illustrates the calculation results of the (B) loss modulus G'' for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (B) the loss modulus of elasticity G'' can be determined simultaneously under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), making it possible to provide resin molded articles with superior dimensional accuracy, strength, appearance, etc., in a shorter time than conventional methods.

[0103] <(C) Complex viscosity|η * How to calculate [Pa s] > From the various intrinsic parameters of the thermoplastic resin obtained by the above method, the complex viscosity (C) of the molten thermoplastic resin |η * This explains how to calculate |. (C) Complex viscosity |η * | is a physical property related to the viscosity of a molten thermoplastic resin when subjected to shear deformation, and is a molten physical property mainly involved in extrusion molding processes that extrude molten thermoplastic resins, and processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping. Using the aforementioned intrinsic parameters, the complex viscosity (C) of the molten thermoplastic resin, |η, is obtained. * | is represented as shown in equation (11) below.

[0104]

number

[0105] The X-axis represents the angular frequency ω or temperature T, which are variables related to the molding conditions, and the Y-axis represents the complex viscosity |η| (C) calculated using equation (11). * By plotting |, we can see the complex viscosity (C) |η under various conditions (molding conditions, etc.). * It is possible to calculate the complex viscosity |η under specific conditions (e.g., molding conditions) by selecting a specific angular frequency ω or temperature T. * | can be calculated arbitrarily.

[0106] Figure 8 illustrates the calculation results of (C) complex viscosity |η*| for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (C) complex viscosity |η*| can be determined simultaneously under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), making it possible to provide resin molded articles with superior dimensional accuracy, strength, appearance, etc., in a shorter time than conventional methods.

[0107] <(D) Shear stress σ s How to calculate [Pa] > From the various intrinsic parameters of the thermoplastic resin obtained by the above method, the (D) shear stress σ of the molten thermoplastic resin is obtained. s I will now explain how to calculate it. (D) Shear stress σ s This is a physical property related to the resistance force generated when a molten thermoplastic resin is subjected to shear deformation, and is a molten physical property mainly involved in extrusion molding processes that extrude molten thermoplastic resins, and processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping. Using the aforementioned intrinsic parameters, the (D) shear stress σ of the molten thermoplastic resin is s This is expressed by equation (12) below. In this case, the angular frequency ω and the shear strain rate γ-dot can be considered equivalent by the Cox-Merz law (see, for example, CW Macosko, Rheology: Principles, Measurements and Applications, VCH Publishers, (1994), WP Cox and EH Merz, Journal of Polymer Science, 28, 619 (1958)).

[0108]

number

[0109] The X-axis represents the shear strain rate γ-dot or temperature T, which are variables related to the molding conditions, and the Y-axis represents the shear stress σ (D) calculated using equation (12) above. s By plotting this, we can determine the (D) shear stress σ under various conditions (molding conditions, etc.).s It is possible to calculate (D) shear stress σ by selecting a specific shear strain rate γ-dot or temperature T. s This can be calculated arbitrarily.

[0110] Figure 9 shows the (D) shear stress σ of ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. s The calculation results are shown as an example. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (D) shear stress σ s Because it is possible to simultaneously determine these properties under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), it becomes possible to provide resin molded articles with superior dimensional accuracy, strength, and appearance in a shorter time than before.

[0111] <(E) Shear viscosity η s How to calculate [Pa s] > From the various intrinsic parameters of the thermoplastic resin obtained by the above method, the (E) shear viscosity η of the molten thermoplastic resin is determined. s I will now explain how to calculate it. (E) Shear viscosity η s This refers to a physical property related to the viscosity of a molten thermoplastic resin when subjected to shear deformation, and is a molten physical property mainly involved in extrusion molding processes that extrude molten thermoplastic resins, and processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping. Using the aforementioned intrinsic parameters, the (E) shear viscosity η of the molten thermoplastic resin is obtained. sThis is expressed by equation (13) below. In this case, the angular frequency and the shear strain rate γ-dot can be considered equivalent by the Cox-Merz law (see, for example, CW Macosko, Rheology: Principles, Measurements and Applications, VCH Publishers, (1994), WP Cox and EH Merz, Journal of Polymer Science, 28, 619 (1958)).

[0112]

number

[0113] The X-axis represents the shear strain rate γ-dot or temperature T, which are variables related to the molding conditions, and the Y-axis represents the shear viscosity η (E) calculated using equation (13). s By plotting this, we can determine the (E) shear viscosity η under various conditions (molding conditions, etc.). s It is possible to calculate (E) shear viscosity η by selecting a specific shear strain rate γ-dot or temperature T. s This can be calculated arbitrarily.

[0114] Figure 10 shows the (E) shear viscosity η of ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. s The calculation results are shown as an example. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (E) shear viscosity η s Because it is possible to simultaneously determine these properties under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), it becomes possible to provide resin molded articles with superior dimensional accuracy, strength, and appearance in a shorter time than before.

[0115] <(F) Method for calculating the first normal stress difference N1 [Pa]> A method for calculating the (F) first normal stress difference N1 of a molten thermoplastic resin from various intrinsic parameters of the thermoplastic resin obtained by the above method will be described. (F) The first normal stress difference N1 is a physical property related to the repulsive force generated perpendicular to the shear deformation direction when a molten thermoplastic resin undergoes shear deformation, and is a molten physical property mainly involved in extrusion molding processes that extrude molten thermoplastic resins, and processes that impart shape to the molten thermoplastic resin, such as film formation / stretching / shaping. Using the aforementioned intrinsic parameters, the (F) first normal stress difference N1 of the molten thermoplastic resin is given by the following equation (14). In this case, the angular frequency ω and the shear strain rate γ-dot can be considered equivalent by the Cox-Merz law (see, for example, CW Macosko, Rheology: Principles, Measurements and Applications, VCH Publishers, (1994), WP Cox and EH Merz, Journal of Polymer Science, 28, 619 (1958)).

[0116]

number

[0117] By plotting the shear strain rate γ-dot or temperature T, which are variables related to the molding conditions, on the X-axis, and the (F) first normal stress difference N1 calculated by equation (14) on the Y-axis, the (F) first normal stress difference N1 can be calculated under various conditions (molding conditions, etc.). Furthermore, by selecting a specific shear strain rate γ-dot or temperature T, the (F) first normal stress difference N1 under specific conditions (molding conditions, etc.) can be arbitrarily calculated.

[0118] Figure 11 illustrates the calculation results of (F) the first normal stress difference N1 for ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (F) the first normal stress difference N1 can be determined simultaneously under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), making it possible to provide resin molded articles with superior dimensional accuracy, strength, appearance, etc., in a shorter time than conventional methods.

[0119] <(G) Elongation stress σ e How to calculate [Pa] > From the various intrinsic parameters of the thermoplastic resin obtained by the above method, the (G) tensile stress σ of the molten thermoplastic resin was determined. e I will now explain how to calculate it. (G) Elongation stress σ e This is a physical property related to the resistance force generated when a molten thermoplastic resin undergoes tensile deformation, and is a molten physical property mainly involved in processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping. Using the aforementioned intrinsic parameters, the (G) tensile stress σ of the molten thermoplastic resin is obtained. e This is expressed by the following equation (15). In this case, the extensional strain rate ε-dot and the shear strain rate γ-dot can be considered equivalent.

[0120]

number

[0121] The X-axis represents the tensile strain rate ε-dot or temperature T, which are variables related to the molding conditions, and the Y-axis represents the tensile stress σ (G) calculated using equation (15) above. eBy plotting this, we can see the (G) tensile stress σ under various conditions (molding conditions, etc.). e It is possible to calculate (G) tensile stress σ by selecting a specific tensile strain rate ε-dot or temperature T. e This can be calculated arbitrarily.

[0122] Figure 12 shows the (G) tensile stress σ of ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramid (nylon 6, Ny6), obtained by the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment. e The calculation results are shown as an example. By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, (G) tensile stress σ e Because it is possible to simultaneously determine these properties under multiple conditions (multiple molding conditions, multiple thermoplastic resin types, etc.), it becomes possible to provide resin molded articles with superior dimensional accuracy, strength, and appearance in a shorter time than before.

[0123] <(H) Extensional viscosity η e How to calculate [Pa s] > From the various intrinsic parameters of the thermoplastic resin obtained by the above method, the (H) extensional viscosity η of the molten thermoplastic resin was determined. e I will now explain how to calculate it. (H) Extensional viscosity η e This refers to a physical property related to the viscosity of a molten thermoplastic resin when it undergoes tensile deformation, and is a molten physical property mainly involved in processes that impart shape to the molten thermoplastic resin, such as film formation, stretching, and shaping. Using the aforementioned intrinsic parameters, the (H) extensional viscosity η of the molten thermoplastic resin is obtained. e This is expressed by the following equation (16). In this case, the extensional strain rate ε-dot and the shear strain rate γ-dot can be considered equivalent.

[0124] [Number]

[0125] On the X-axis, the elongation strain rate ε-dot or temperature T, which are variables related to the molding conditions, and on the Y-axis, the (H) elongation viscosity η calculated by the above formula (16). e By plotting, the (H) elongation viscosity η in various condition (such as molding conditions) ranges can be calculated. e Also, by selecting a specific elongation strain rate ε-dot or temperature T, the (H) elongation viscosity η under specific conditions (such as molding conditions) can be arbitrarily calculated. e

[0126] In FIG. 13, the calculated results of the (H) elongation viscosity η of ethylene-vinyl alcohol resin (EVOH), maleic anhydride-modified linear low-density polyethylene (MAH-LLDPE), linear low-density polyethylene (LLDPE), polypropylene homopolymer (Homo-PP), and polycapramide (nylon 6, Ny6) obtained by the melt physical property calculation device, melt physical property calculation method, and computer program according to this embodiment are illustrated. e By using the melt physical property calculation device, melt physical property calculation method, and computer program according to this embodiment, the (H) elongation viscosity η can be simultaneously obtained under a plurality of conditions (such as a plurality of molding conditions, a plurality of thermoplastic resin types, etc.). Therefore, it is possible to provide a resin molded body with excellent dimensional accuracy, strength, appearance, etc. in a shorter time than before. e

[0127] The calculation method for at least one or more melt physical properties selected from the above (A) to (H) can be applied to one type of thermoplastic resin, and can also be applied to a composite obtained by blending two or more types of thermoplastic resins.

[0128] The melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment calculate at least one melt property selected from (A) to (H), but the number is not particularly limited, preferably two or more, more preferably three or more, even more preferably four or more, particularly preferably five or more, even more preferably six or more, most preferably seven or more, and especially preferably eight or more. When the number of melt properties to be calculated is within the above range, there is a tendency to be able to improve molding defects in resin molded articles more efficiently than in the conventional method.

[0129] <Resin molded article and method for manufacturing the same> The resin molded article according to this embodiment is obtained by melt-molding a thermoplastic resin based on the melt properties of the thermoplastic resin obtained using at least one of the melt property calculation device, melt property calculation method, and computer program according to this embodiment.

[0130] The aforementioned resin molded article can be made stronger or given other functions by blending two or more types of thermoplastic resins.

[0131] When producing a resin molded article by blending two or more thermoplastic resins, the manufacturing method can be carried out by known methods. For example, methods include dry blending by mixing two or more thermoplastic resins in predetermined proportions, melt kneading by mixing two or more thermoplastic resins in predetermined proportions, and adding and mixing the other thermoplastic resins to a solution containing a specific thermoplastic resin from among the two or more thermoplastic resins, and then removing the solvent from the solution. Among these, the melt kneading method is preferred from the viewpoint of cost and stability of physical properties.

[0132] Examples of the shapes of the resin molded articles include films, resin pellets, cups, trays, bottles, tanks, pipes, tubes, transport pallets, chairs, desks, stakes, and the like.

[0133] If the resin molded product is in the form of a film, (heat) stretching treatment is performed as needed. The stretching treatment may be uniaxial stretching or biaxial stretching, and in the case of biaxial stretching, it may be simultaneous stretching or sequential stretching. Furthermore, among the stretching methods, those with a high stretch ratio, such as roll stretching, tenter stretching, tubular stretching, stretch blowing, and vacuum pressure forming, can also be used.

[0134] The stretching temperature is usually selected from a range of 40 to 170°C, preferably 60 to 160°C. If the stretching temperature is too low, the stretchability tends to be poor, and if it is too high, it tends to be difficult to maintain a stable stretched state.

[0135] Furthermore, the film may be heat-set after stretching for the purpose of imparting dimensional stability. Heat-setting can be carried out by well-known means; for example, the stretched film or sheet is heat-treated at a temperature of typically 80 to 180°C, preferably 100 to 165°C, for typically 2 to 600 seconds while maintaining tension.

[0136] Furthermore, when using a single-layer stretched film as a shrink film, in order to impart heat shrinkability, the aforementioned heat fixing process can be omitted. Instead, for example, the stretched film can be cooled and fixed by applying cold air.

[0137] Furthermore, it is possible to obtain single-layer containers (resin molded products) such as cups, trays, bottles, and tanks from the aforementioned film. The method for producing single-layer containers typically employs deep drawing, specifically vacuum forming, pressure forming, vacuum pressure forming, and plug-assisted vacuum pressure forming. When obtaining tube- or bottle-shaped single-layer containers from a single-layer parison (a hollow tubular pre-molded product before blowing), blow molding is employed, specifically including extrusion blow molding (double-head type, mold-moving type, parison shift type, rotary type, accumulator type, horizontal parison type, etc.), cold parison blow molding, injection blow molding, and biaxial stretch blow molding (extrusion cold parison biaxial stretch blow molding, injection cold parison biaxial stretch blow molding, injection molding in-line biaxial stretch blow molding, etc.).

[0138] Furthermore, the film (resin molded body) can be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making, deep drawing, box making, tube making, splitting, etc., as needed.

[0139] The thickness of the resin molded article (including stretched articles) is set appropriately depending on the application, packaging form, required physical properties, etc., but is usually 10 to 500,000 μm, preferably 30 to 300,000 μm, and particularly preferably 50 to 200,000 μm. If the thickness of the resin molded article is too thin, the mechanical strength tends to decrease. If the thickness of the resin molded article is too thick, the mechanical strength becomes excessive, resulting in the use of unnecessary raw materials, which is economically undesirable.

[0140] Furthermore, if the shape of the resin molded body is a resin pellet, any shape can be used for the resin pellet, such as a sphere, oval, cylindrical, cubic, or rectangular prism. Typically, they are oval or cylindrical, and their size is determined from the viewpoint of convenience when used later as a molding material. In the case of an oval shape, the short axis is usually 1 to 6 mm, preferably 2 to 5 mm, and the long axis is usually 1 to 6 mm, preferably 2 to 5 mm. In the case of a cylindrical shape, the diameter of the base is usually 1 to 6 mm, preferably 2 to 5 mm, and the length is usually 1 to 6 mm, preferably 2 to 5 mm.

[0141] The method for producing the resin pellets is not particularly limited, but examples include the methods shown in (i) to (iv) below. Note that multiple methods shown in (i) to (iv) below may be used in combination. (i) A method of dry blending resin pellets containing at least one type of thermoplastic resin in a predetermined proportion (dry blending method). (ii) A method of immersing resin pellets containing at least one thermoplastic resin in a solution containing other thermoplastic resins, and then drying the resin pellets (immersion method). (iii) A method of preparing resin pellets by mixing at least one thermoplastic resin in a predetermined proportion and melt-kneading it. (iv) A method of producing resin pellets by adding other thermoplastic resins to a solution containing at least one type of thermoplastic resin, mixing them, and then removing the solvent from the solution (solution mixing method).

[0142] Among these, method (iii), which involves blending at least one thermoplastic resin in a predetermined proportion, melt-kneading it, and then producing resin pellets (melt-kneading method), is practical and industrially preferable in terms of productivity and economic efficiency. Furthermore, when blending the other additives, a thermoplastic resin containing the other additives can be obtained by following the methods (i) to (iv) described above.

[0143] As the means for dry blending in the method (i) above, for example, known mixing devices such as a rocking mixer, a ribbon blender, or a line mixer can be used.

[0144] In the dry blending in the method (i) above, it is preferable to adjust the moisture content of the resin pellets to 0.1 to 5% by mass (more preferably 0.5 to 4% by mass, particularly preferably 1 to 3% by mass). If the moisture content is too low, the resin pellets tend to be easily cracked. Conversely, if it is too high, the resin pellets foam during melt molding, and the quality of the resin molded body tends to deteriorate.

[0145] Note that the moisture content of the resin pellets is measured and calculated by the following method. [Method for Measuring Moisture Content] After weighing the resin pellets with an electronic balance (W1: unit g), they are placed in a hot air oven type dryer maintained at 150°C and dried for 5 hours, and then the mass after further cooling in a desiccator for 30 minutes is weighed in the same way (W2: unit g), and calculated from the following formula. Moisture content (%) = {(W1 - W2) / W1} × 100 <​​​​​​The means for melt-kneading in the method described in (iii) above can be known melt-kneading equipment such as a kneader, ruder, extruder, mixing roll, Banbury mixer, or plastmill, and it is preferable to melt-knead at 150 to 300°C (more preferably 180 to 280°C) for about 1 to 20 minutes. In particular, using a single-screw or twin-screw extruder is industrially advantageous in that pellets can be easily obtained, and it is also preferable to provide a vent suction device, gear pump device, screen device, etc. as needed. In particular, by providing one or more vent holes in the extruder and suctioning under reduced pressure to remove moisture and by-products (thermally decomposed low molecular weight products, etc.), or by continuously supplying an inert gas such as nitrogen into the hopper to prevent oxygen from entering the extruder, it is possible to obtain resin pellets of excellent quality with reduced thermal discoloration and thermal degradation.

[0148] Furthermore, the method of supplying to melting and kneading equipment such as extruders is not particularly limited. 1) A method of dry-blending at least one type of thermoplastic resin and supplying it to an extruder in one batch. 2) A method of supplying at least one type of thermoplastic resin to an extruder and melting it, and then supplying other thermoplastic resins to it (solid side feed method). 3) A method of supplying at least one type of thermoplastic resin to an extruder and melting it, then supplying other thermoplastic resins in a molten state (melt-side feed method). While several methods can be mentioned, method 1) is the most practical in terms of the simplicity of the equipment and the cost of the blended material.

[0149] Furthermore, from the perspective of reducing environmental impact, the following methods 4) to 6) are also preferable, which use scrap of resin molded products (e.g., resin pellets, films, sheets, cups, trays, bottles, tanks, pipes, tubes, transport pallets, chairs, desks, stakes, etc.) that have been molded and / or used by consumers at least once as raw materials. 4) A method of dry-blending the scrap and the virgin thermoplastic resin and supplying them together to an extruder. 5) A method of supplying either the scrap or the virgin thermoplastic resin to an extruder and melting it, and then supplying the other scrap or virgin thermoplastic resin to it (solid side feed method). 6) A method of supplying either the scrap or the virgin thermoplastic resin to an extruder and melting it, then supplying the other molten scrap or virgin thermoplastic resin (melt-side feed method).

[0150] The aforementioned scrap may be end pieces or defective products recovered during the manufacturing of resin molded articles, and furthermore, the scrap may be a resin molded article containing a recovered material layer that includes the scrap. That is, a resin molded article containing a recovered material layer made of thermoplastic resin obtained from end pieces or defective products generated during the manufacturing of resin molded articles may be manufactured, the scrap of the resin molded article may be recovered, and used as a raw material for the aforementioned resin molded article.

[0151] The aforementioned scrap is preferably crushed to an appropriate size, and the scrap may be obtained from one type of resin molded product, or a mixture of scraps obtained from two or more types of resin molded products may be used.

[0152] Furthermore, the scrap may consist of resin molded products such as multilayer structures discarded by general consumers as plastic waste. In other words, resin molded products such as multilayer structures discarded by general consumers as plastic waste may be collected, and the collected scrap may be used as raw material for resin molded products.

[0153] Furthermore, known methods can be used to produce resin pellets after melt-kneading, including the strand-cut method and the hot-cut method (air-cut method, underwater-cut method). In terms of industrial productivity, the strand-cut method is preferred.

[0154] The solvent used in the solution mixing method in method (iv) above may be any known good solvent, and heating and pressurization may be applied as needed during dissolution, and the concentration may also be arbitrary. At least one thermoplastic resin may be dissolved in a solution or paste, and other thermoplastic resins may be blended into it. In this case, the other thermoplastic resins may be blended in the form of a solid, solution, dispersion, etc. After compounding, the thermoplastic resin solution or paste, which has been uniformly stirred, is pelletized using the known method described above. The underwater cut method is preferred in terms of industrial productivity. The resulting pellets are dried using a known method.

[0155] In this way, a resin molded article according to this embodiment can be obtained.

[0156] <Multilayer structure> Furthermore, it is preferable that the resin molded article is a multilayer structure having at least two thermoplastic resin layers made of at least one type of thermoplastic resin. By having at least two thermoplastic resin layers, the multilayer structure can be made stronger or given other functions.

[0157] Examples of thermoplastic resin layers in the multilayer structure include layers made of polyolefin resin containing polar groups (hereinafter simply referred to as "polar group-containing PO layer"), layers made of polyamide resin (hereinafter simply referred to as "polyamide layer"), layers made of EVOH (hereinafter simply referred to as "EVOH layer"), and layers made of polyolefin resin that do not contain polar groups (hereinafter simply referred to as "PO layer").

[0158] The polar group-containing PO layer may also be blended with rubber / elastomer components such as polyisobutylene and ethylene-propylene rubber, as well as polyolefin resins that do not contain polar groups, EVOH, etc., to the extent that they do not impede the effects of the present invention.

[0159] Furthermore, the polar group-containing PO layer, polyamide layer, and PO layer may contain at least one of the other additives described above for thermoplastic resins, within a range that does not impede the spirit of the present invention (for example, 30% by mass or less, preferably 10% by mass or less).

[0160] The layer configuration of the multilayer structure is such that the EVOH layer is (A) [A1, A2, ...], the polar group-containing PO layer is (B) [B1, B2, ...], the polyamide layer is (C) [C1, C2, ...], and the PO layer is (D) [D1, D2, ...], then D / B / A, A1 / A2 / A3, D / A1 / B / A2, D1 / A / B / D2, A1 / B / A2 Any combination is possible, such as E1 / I1 / A / I2 / E2, E1 / I1 / A1 / A2 / A3 / I2 / E2, E1 / A1 / I / A2 / E2, E / I / A / U, E / U / A1 / I / A2, E1 / U / A / I / E2, U / A1 / I / A2, E1 / I1 / U / A / I2 / E2, E1 / U1 / A1 / I / A2 / U2 / E2, etc. Furthermore, when the recovered material layer containing scrap obtained by remelting ends, defective products, etc., generated during the manufacturing process of the resin molded body such as the multilayer structure is denoted as (R) [R1, R2, ...], then E / R / I / A, A1 / R / A2 / A3, E / R / A1 / I / A2, E1 / R / A / I / E2, R1 / A1 / I / A2 / R2, R1 / A1 / A2 / A3 / R2, E1 / R1 / I1 / I / I It is also possible to use configurations such as 2 / R2 / E2, E1 / R1 / I1 / A1 / A2 / A3 / I2 / R2 / E2, E1 / R1 / A1 / I / A2 / R2 / E2, E / R / I / A / U, E / R / U / A1 / I / A2, E1 / R / U / A / I / E2, R1 / U / A1 / I / A2 / R2, E1 / R1 / I1 / U / A / I2 / R2 / E2, E1 / R1 / U1 / A1 / I / A2 / U2 / R2 / E2, etc. Furthermore, with respect to any EVOH layer (A), the configuration of the layer stacked in one stacking direction and the configuration of the layer stacked in the other direction may be identical (symmetrical) or different (asymmetrical). Furthermore, with respect to any EVOH layer (A), the thickness of the layer stacked in one stacking direction and the thickness of the layer stacked in the other direction may be the same (symmetrical) or different (asymmetrical).

[0161] The lamination method for producing the aforementioned multilayer structure can be carried out by known methods. For example, methods include melt-extrude lamination of a film made of one thermoplastic resin onto a film made of another thermoplastic resin, co-extrusion molding of a thermoplastic resin and another thermoplastic resin, preparing a film (layer) made of one thermoplastic resin and another film (layer) made of another thermoplastic resin separately and dry-laminating them using known adhesives such as organic titanium compounds, isocyanate compounds, polyester compounds, and polyurethane compounds, and coating a thermoplastic resin solution onto another substrate and then removing the solvent. Among these, co-extrusion molding is preferred from the viewpoint of cost and environmental impact.

[0162] The multilayer structure is then subjected to (heat) stretching as necessary. The stretching process may be uniaxial or biaxial, and in the case of biaxial stretching, it may be simultaneous or sequential. Furthermore, as for the stretching method, methods with a high stretch ratio, such as roll stretching, tenter stretching, tubular stretching, stretch blowing, and vacuum pressure forming, can also be used. The stretching temperature is usually selected from a range of 40 to 170°C, preferably 60 to 160°C. If the stretching temperature is too low, the stretchability tends to be poor, and if it is too high, it tends to be difficult to maintain a stable stretched state.

[0163] Furthermore, heat setting may be performed after stretching to impart dimensional stability. Heat setting can be carried out by well-known means; for example, the stretched multilayer structure (stretched film) is heat-treated at a temperature of typically 80 to 180°C, preferably 100 to 165°C, for typically 2 to 600 seconds while maintaining tension.

[0164] Furthermore, when using a multilayer stretched film obtained using a thermoplastic resin as a shrinkable film, in order to impart heat shrinkability, the aforementioned heat fixing process can be omitted, and instead, a treatment such as applying cold air to the stretched film to cool and fix it can be performed.

[0165] Furthermore, in some cases, it is possible to obtain multilayer containers (resin molded products) such as cups, trays, bottles, and tanks from the multilayer structure. The method for manufacturing multilayer containers is typically deep drawing, specifically including vacuum forming, pressure forming, vacuum pressure forming, and plug-assisted vacuum pressure forming. When obtaining tube or bottle-shaped multilayer containers from multilayer parisons (hollow tubular pre-molded products before blowing), blow molding is employed, specifically including extrusion blow molding (double-head type, mold-moving type, parison shift type, rotary type, accumulator type, horizontal parison type, etc.), cold parison blow molding, injection blow molding, and biaxial stretch blow molding (extrusion cold parison biaxial stretch blow molding, injection cold parison biaxial stretch blow molding, injection molding in-line biaxial stretch blow molding, etc.).

[0166] The aforementioned multilayer structure (resin molded body) can be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or molten coating treatment, bag making, deep drawing, box making, tube making, splitting, etc., as needed.

[0167] The thickness of the multilayer structure (including stretched versions), and furthermore, the thickness of the EVOH layer, polyamide layer, polar group-containing PO layer, and PO layer constituting the multilayer structure, are set appropriately depending on the layer configuration, type of thermoplastic resin, application, packaging form, required physical properties, etc.

[0168] The total thickness of the multilayer structure (including stretched structures) is typically 10 to 5000 μm, preferably 30 to 3000 μm, and particularly preferably 50 to 2000 μm. If the total thickness of the multilayer structure is too thin, the gas barrier properties and mechanical strength may decrease. Conversely, if the total thickness of the multilayer structure is too thick, the gas barrier properties and mechanical strength will be excessive, leading to the use of unnecessary raw materials, which tends to be uneconomical.

[0169] The thickness of the EVOH layer (a) is typically 1 to 500 μm, preferably 3 to 300 μm, and particularly preferably 5 to 200 μm. The thickness of the polar group-containing PO layer (a) is usually 0.5 to 250 μm, preferably 1 to 150 μm, and particularly preferably 3 to 100 μm. The thickness of the polyamide layer (c) is usually 1 to 2000 μm, preferably 3 to 1000 μm, and particularly preferably 5 to 500 μm. The thickness of the aforementioned PO layer (E) is typically 5 to 3000 μm, preferably 10 to 2000 μm, and particularly preferably 20 to 1000 μm. The thickness of the recovered material layer (R) is typically 5 to 3000 μm, preferably 10 to 2000 μm, and particularly preferably 20 to 1000 μm. The above values ​​are the sum of the thicknesses of the same type of layer if at least one of the following layers is present in two or more layers: EVOH layer (a), polar group-containing PO layer (b), polyamide layer (c), and PO layer (d) recovered material layer (R).

[0170] Furthermore, the ratio of the thickness of the EVOH layer (A) to the recovered material layer (R) in the multilayer structure (EVOH layer (A) / recovered material layer (R)) is the ratio of the thickest layers when there are multiple layers, and is usually 1 / 99 to 50 / 50, preferably 2 / 98 to 45 / 55, particularly preferably 5 / 95 to 40 / 60, and especially preferably 10 / 90 to 35 / 65. When the value is within the above range, the effects of the present invention tend to be more pronounced; when it is smaller than the above range, the gas barrier properties and mechanical strength tend to be insufficient; and when it is larger than the above range, the multilayer structure tends to crack easily.

[0171] Furthermore, in a multilayer structure, the thickness ratio of the EVOH layer (A) to the polyamide layer (C) (EVOH layer (A) / polyamide layer (C)) is the ratio of the thickest layers when there are multiple layers, and is usually 10 / 90 to 99 / 1, preferably 20 / 80 to 80 / 20, and particularly preferably 40 / 60 to 60 / 40. When this value is within the above range, the effects of the present invention tend to be more pronounced; when it is smaller than the above range, the gas barrier properties tend to be insufficient; and when it is larger than the above range, the mechanical strength tends to be insufficient.

[0172] Furthermore, in a multilayer structure, the thickness ratio of the EVOH layer (A) to the polar group-containing PO layer (B) (EVOH layer (A) / polar group-containing PO layer (B)) is the ratio of the thickest layers when there are multiple layers, and is usually 10 / 90 to 99 / 1, preferably 20 / 80 to 95 / 5, and particularly preferably 50 / 50 to 90 / 10. When this value is within the above range, the effects of the present invention tend to be more pronounced; when it is smaller than the above range, the gas barrier properties tend to be insufficient; and when it is larger than the above range, the adhesive strength tends to be insufficient.

[0173] The aforementioned multilayer structure is useful as a raw material for various types of packaging, including general foods, condiments such as mayonnaise and salad dressings, fermented foods such as miso, oily foods such as salad oil, beverages, cosmetics, and pharmaceuticals.

[0174] <Method for improving molding defects in molded products> Next, a method for improving molding defects in resin molded articles according to this embodiment will be described. The method for improving molding defects in resin molded articles according to this embodiment is a method for highly improving various molding defects, such as dimensional defects, shape defects, and appearance defects, that occur when the resin molded article is manufactured using the manufacturing method described above. The molding defect improvement method described above is characterized by the following steps when manufacturing a resin molded article according to this embodiment using the manufacturing method described above: first, calculating the shear strain rate of the molten thermoplastic resin generated at the wall surface of the molding die lip and / or the extensional strain rate at the rapid contraction section immediately before the molding die lip; then, calculating the molten properties (D) to (H) of each thermoplastic resin molten material corresponding to the calculated shear strain rate and / or extensional strain rate at the temperature of each thermoplastic resin molten material; and finally, adjusting each thermoplastic resin (type, number, combination, etc.) and molding conditions (temperature, discharge rate, shape and size of manufacturing equipment, etc.) so that all values ​​of the molten properties (D) to (F) at the wall surface of the molding die lip and / or the molten properties (G) to (H) at the rapid contraction section immediately before the molding die lip fall within a specific range.

[0175] Apparent shear strain rate γ of the molten thermoplastic resin at the molded die lip. A - dot (γ A A symbol with a (·) above it; hereafter simply referred to as "γ A - The dot (referred to as "-dot") can be calculated using known methods, for example, the following method, depending on the discharge rate of the thermoplastic resin molten material and the flow path shape of the molding die lip.

[0176] The apparent shear strain rate γ generated at the wall surface when a molten thermoplastic resin flows through a capillary-shaped channel. A - The dot can be calculated from the following formula (17).

[0177]

number

[0178] In equation (17) above, Q is the discharge volume (cm³) of the molten thermoplastic resin. 3 γ is the apparent shear strain rate at the wall surface when a molten thermoplastic resin flows through a slit-shaped channel. A - The dot can be calculated from the following formula (18).

[0179]

number

[0180] In equation (18) above, Q is the discharge volume (cm³) of the molten thermoplastic resin. 3 ( / second), W represents the width of the slit-shaped channel (cm), and H represents the height of the slit-shaped channel (cm).

[0181] Furthermore, the apparent shear strain rate γ at the wall surface when a thermoplastic resin molten material flows through a cylindrical channel. A - The dot can be calculated from the following formula (19).

[0182]

number

[0183] In equation (19) above, Q is the discharge volume (cm³) of the molten thermoplastic resin. 3 R0 is the outer radius of the cylindrical channel (cm), R i This indicates the inner radius (cm) of the cylindrical channel.

[0184] Furthermore, if the molding die lip has a capillary-shaped flow channel, the tensile strain rate ε-dot when the molten thermoplastic resin undergoes tensile deformation in the sharp contraction section immediately before the molding die lip can be calculated from the following equation (20) and equation (17) proposed by Cogswell (Polymer Engineering Science, Vol. 12, pp. 64-73 (1972)).

[0185]

number

[0186] In equation (20) above, θ represents the inflow angle (°) of the sharply contracted section immediately before the molding die lip.

[0187] Furthermore, if the molding die lip has a slit-shaped flow channel, the tensile strain rate ε-dot when the molten thermoplastic resin undergoes tensile deformation in the sharp contraction section immediately before the molding die lip can be calculated from the following equation (21) and equation (18) proposed by Cogswell (Polymer Engineering Science, Vol. 12, pp. 64-73 (1972)).

[0188]

number

[0189] In equation (21) above, θ represents the inflow angle (°) of the sharply contracted section immediately before the molding die lip.

[0190] Furthermore, if the molding die lip has a cylindrical flow channel shape, the tensile strain rate ε-dot when the molten thermoplastic resin undergoes tensile deformation in the sharp contraction section immediately before the molding die lip can be approximately calculated from equations (21) and (19).

[0191] Subsequently, the shear strain rate γ-dot and / or extensional strain rate ε-dot at the wall surface, obtained using equations (17) to (20), and the shift factor a of the thermoplastic resin at temperature T are used. T And, the intrinsic parameter of thermoplastic resin (relaxation time τ) i Relaxation modulus G i By substituting ) into equations (12) to (16) above, the melt properties (D) to (F) of the molten thermoplastic resin at the wall surface of the molding die lip portion, and / or the melt properties (G) to (H) of the molten thermoplastic resin at the sharp contraction portion immediately before the molding die lip can be determined, respectively. At this time, the relaxation time τ i Therefore, the reciprocal of the shear strain rate, 1 / γ-dot, and / or the reciprocal of the extensional strain rate, 1 / ε-dot, can be considered equivalent. Furthermore, the shift factor a of the thermoplastic resin at the temperature T. T This refers to the temperature T of the thermoplastic resin and the intrinsic parameters of the thermoplastic resin (activation energy E). a The constants a and b, and the gas constant R can be obtained by substituting them into equation (7).

[0192] The method for improving molding defects in resin molded articles according to this embodiment is based on the (D) shear stress σ at the wall surface of the molded die lip portion of the thermoplastic resin molten material, regardless of the flow path shape of the molded die lip portion. s (E) Shear viscosity η s (F) First normal stress difference N1, (G) tensile stress σ in the sharp shrinkage section immediately before the molding die lip of the thermoplastic resin molten material. e , (H) extensional viscosity η e It is preferable that all of the following conditions are met. (D) Shear stress σ s The pressure is preferably 300 to 300,000 Pa, more preferably 400 to 250,000 Pa, and particularly preferably 500 to 200,000 Pa. (E) Shear viscosity η s The power is preferably 30 to 3,000,000 Pas, more preferably 100 to 2,500,000 Pas, and particularly preferably 150 to 2,000,000 Pas. (F) The first normal stress difference N1 is preferably 100 to 2,000,000 Pa, more preferably 350 to 1,500,000 Pa, and particularly preferably 500 to 1,000,000 Pa. (G) Elongation stress σ e The pressure is preferably 900 to 900,000 Pa, more preferably 1,500 to 600,000 Pa, and particularly preferably 2,000 to 500,000 Pa. (H) Extensional viscosity η e The power is preferably 90 to 9,000,000 Pas, more preferably 150 to 6,000,000 Pas, and particularly preferably 200 to 5,000,000 Pas. By adjusting each thermoplastic resin (type, quantity, combination, etc.) and molding conditions (temperature, discharge rate, shape and size of manufacturing equipment, etc.) to satisfy all of these conditions, various molding defects related to dimensional defects, shape defects, and appearance defects of resin molded products can be improved to a high degree.

[0193] In this case, the method for improving molding defects in resin molded articles can be applied to a single type of thermoplastic resin, and further, to blends of two or more types of thermoplastic resins. Similarly, with blends of two or more types of thermoplastic resins, by adjusting the melting properties (D) to (F) of the molten thermoplastic resin at the wall surface of the molding die lip, and the melting properties (G) and (H) at the sharp shrinkage section immediately before the molding die lip, to satisfy all of the above ranges, various molding defects related to dimensional defects, shape defects, and appearance defects of the molded article can be improved to a high degree. Although the reason is not clear, it is presumed that because all the values ​​of the aforementioned molten properties (D) to (H) satisfy the above range, the complex flow behavior of the thermoplastic resin molten material during the melt molding process becomes very stable, resulting in a significant improvement in various molding defects.

[0194] Furthermore, the molding defect improvement method for molded articles according to this embodiment can be applied as a method to highly improve various molding defects such as dimensional defects, shape defects, and appearance defects that occur when manufacturing the multilayer structure using the manufacturing method described above.

[0195] The following describes methods for improving molding defects when the resin molded product is a multilayer structure. The method for improving molding defects in the aforementioned multilayer structure is a method for highly improving various molding defects, such as dimensional defects, shape defects, and appearance defects, that occur when manufacturing the multilayer structure using the aforementioned manufacturing method.

[0196] As the multilayer structure, a multilayer structure is preferred in which a PO layer (d) is laminated on at least one surface of an EVOH layer (a) and / or a polyamide layer (c) via a polar group-containing PO layer (b). The method for improving molding defects in the multilayer structure is to ensure that the position of the lamination interface (A / B) between the EVOH layer (A) closest to the die lip wall surface in the molded die lip portion, and / or the position of the lamination interface (C / B) between the polyamide layer (C) and the polar group-containing PO layer (B), satisfies the following equation (22), and the shear strain rate of 1S at the molding temperature of the multilayer structure of the EVOH layer (A) and / or polyamide layer (C) and PO layer (D), as determined using the melt property calculation device, melt property calculation method, and computer program, is -1 (E) Shear viscosity η s , and extensional strain rate 1S -1 (H) Extensional viscosity η e However, it is characterized by satisfying the following equation (23). 0.2 ≤ {(distance from the molded die lip wall of the laminate interface (A / B) and / or the laminate interface (C / B)) / (thickness of the molded die lip)} ≤ 0.8 ···(22) 0.5 ≤ {(η e / η s )E / (η e / η s )A}≦4.5 and / or 0.5≦{(η e / η s )E / (ηe / η s )U}≦4.5···(23)

[0197] In formula (22) above, preferably 0.25 ≤ {(distance from the molded die lip wall surface of the laminated interface (A / B) and / or the laminated interface (C / B)) / (thickness of the molded die lip portion)} ≤ 0.7, and particularly preferably 0.3 ≤ {(distance from the molded die lip wall surface of the laminated interface (A / B) and / or the laminated interface (C / B)) / (thickness of the molded die lip portion)} ≤ 0.7. Furthermore, in formula (23), preferably 0.5 ≤ {(η e / η s )E / (η e / η s )A} ≤ 4.5, and more preferably 0.6 ≤ {(η e / η s )E / (η e / η s )A}≦4.3, particularly preferably 0.7≦{(η e / η s )E / (η e / η s )A} ≤ 4.0. By adjusting each thermoplastic resin (type, number, combination, etc.) and molding conditions (temperature, discharge rate, shape and size of manufacturing equipment, etc.) to satisfy equations (22) and (23), various molding defects related to dimensional defects, shape defects, and appearance defects of molded products can be greatly improved. Although the reason is not clear, it is presumed that by satisfying the ranges of equations (22) and (23), the complex multilayer flow behavior of the thermoplastic resin molten material during the multilayer melt extrusion molding process becomes very stable, resulting in a significant improvement in various molding defects.

[0198] The method for improving molding defects in the aforementioned multilayer structure can be applied to a single thermoplastic resin layer, and further, to a blended layer made by blending two or more thermoplastic resins.

[0199] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

[0200] <Example 1> [Manufacturing of resin molded products] A resin molded body was obtained by supplying linear low-density polyethylene 1 (LLDPE1) [UF240, manufactured by Nippon Polyethylene Co., Ltd., MFR 2.1g / 10 min (190℃, load 2160g)] as a thermoplastic resin to a capillary rheometer (RHEOGRAPH 20, manufactured by Gottfert) and extruding it under the following conditions. Shear strain rate on the wall surface of the molded die lip: 23s -1 Extension strain rate at the sharp contraction section immediately before the molding die lip: 2.3s -1 Molding temperature: 210℃ Capillary die: Length 10mm, Diameter 1mm Preheating time: 10 min

[0201] [Method for determining the shear strain rate on the wall surface of the molded die lip] The discharge volume Q (cm) of the molded body extruded from the capillary rheometer (Gottfert RHEOGRAPH 20) under the above conditions. 3 The shear strain rate γ is measured ( / second) and substituted into the following equation (17) to obtain the apparent shear strain rate γ A - I looked for a dot.

[0202]

number

[0203] [Method for determining the molten properties (D) to (F) of the wall surface of the molded die lip] The apparent shear strain rate γ obtained above A -The melt properties (D) to (F) at the wall surface of the molded die lip were determined by using the dots, the manufacturing conditions of the resin molded body, and the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment.

[0204] [How to determine the tensile strain rate in the sharp shrinkage section immediately before the molding die lip] The discharge volume Q (cm) of the molded body extruded from the capillary rheometer (Gottfert RHEOGRAPH 20) under the above conditions. 3 The tensile strain rate ε-dot was determined by measuring the value ( / second) and substituting it into the following equation (20).

[0205]

number

[0206] [Method for determining the melt properties (G) to (H) in the sharp shrinkage section just before the molding die lip lip] The fusion properties (G) to (H) in the rapid contraction section immediately before the molding die lip lip were determined by using the extensional strain rate ε-dot obtained above, the manufacturing conditions of the resin molded body, and the fusion property calculation device, fusion property calculation method, and computer program according to this embodiment.

[0207] The appearance of the resin molded articles obtained above was evaluated visually based on the evaluation criteria shown below. The evaluation results are shown in Table 1 below. [Evaluation Criteria] A; Very good B; Good C; bad D; Very bad

[0208] <Example 2> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that linear low-density polyethylene 2 (LLDPE2) [GS650, manufactured by ENEOS NUC, MFR 0.7 g / 10 min (190°C, load 2160 g)] was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0209] <Example 3> In Example 1, a molded article was prepared in the same manner as in Example 1, except that a polyolefin resin containing polar groups (PLEXAR PX3236, manufactured by LyondellBasell, MFR 2.0 g / 10 min [190°C, load 2160 g]) was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0210] <Example 4> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that polypropylene (Novatec PP EA7AD, manufactured by Nippon Polypropylene Co., Ltd., MFR 1.3g / 10 min [230°C, load 2160g]) was used as the thermoplastic resin and the molding temperature was 180°C. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0211] <Example 5> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that polypropylene (Novatec PP EA7AD, manufactured by Nippon Polypropylene Co., Ltd., MFR 1.3g / 10 min [230℃, load 2160g]) was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0212] <Example 6> In Example 1, a polyolefin resin containing polar groups (PLEXAR PX6002, manufactured by LyondellBasell, MFR 2.7 g / 10 min [230°C, load 2160 g]) was used as the thermoplastic resin, and a resin molded article was prepared in the same manner as in Example 1, except that the molding temperature was 180°C. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0213] <Example 7> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that a polyolefin resin containing polar groups (PLEXAR PX6002, manufactured by LyondellBasell, MFR 2.7 g / 10 min [230°C, load 2160 g]) was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0214] <Example 8> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that EVOH1 (ethylene structural unit content 29 mol%, degree of saponification 99.7 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g)) was used as the thermoplastic resin and the molding temperature was 190°C. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0215] <Example 9> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that EVOH1 (ethylene structural unit content 29 mol%, degree of saponification 99.7 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g)) was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0216] <Example 10> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that pellets of EVOH1 (ethylene structural unit content 29 mol%, degree of saponification 99.7 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g)) and pellets of EVOH2 (ethylene structural unit content 44 mol%, degree of saponification 99.7 mol%, MFR 3.5 g / 10 min (210°C, load 2160 g)) were dry-blended in a mass ratio of (EVOH1) / (EVOH2) = 75 / 25 as the thermoplastic resin. The appearance evaluation of the obtained resin molded article was carried out in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0217] <Example 11> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that EVOH3 (ethylene structural unit content 38 mol%, degree of saponification 99.7 mol%, MFR 50 g / 10 min (210°C, load 2160 g)) was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0218] <Example 12> In Example 11, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0219] <Example 13> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that pellets of EVOH1 (ethylene structural unit content 29 mol%, degree of saponification 99.7 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g)) and polyamide 6 (Novamid 1020, manufactured by DSM) were melt-kneaded in a twin-screw extruder at a mass ratio of (EVOH1) / (polyamide 6) = 90 / 10. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0220] <Example 14> In Example 1, a resin molded article was prepared in the same manner as in Example 1, except that polyamide 6 (Novamid 1020, manufactured by DSM) was used as the thermoplastic resin. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0221] <Comparative Example 1> In Example 1, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0222] <Comparative Example 2> In Example 2, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0223] <Comparative Example 3> In Example 3, the shear strain rate at the wall surface of the molded die lip was 2304 s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip is set to 226 s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0224] <Comparative Example 4> In Example 4, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0225] <Comparative Example 5> In Example 5, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0226] <Comparative Example 6> In Example 6, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0227] <Comparative Example 7> In Example 7, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0228] <Comparative Example 8> In Example 8, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0229] <Comparative Example 9> In Example 9, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1 Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0230] <Comparative Example 10> In Example 10, the shear strain rate at the wall surface of the molded die lip was set to 2304s. -1 Furthermore, the tensile strain rate at the sharp contraction section immediately before the molding die lip was set to 226s. -1Resin molded articles were prepared in the same manner as described above. The appearance of the obtained resin molded articles was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0231] <Comparative Example 11> In Example 11, a resin molded article was prepared in the same manner as in Example 1, except that the molding temperature was set to 270°C. The appearance of the obtained resin molded article was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0232] [Table 1]

[0233] From the results in Table 1, the resin molded articles of Examples 1 to 14 had excellent appearance. Therefore, the (D) shear stress σ at the wall surface of the molded die lip portion of the molten thermoplastic resin s (E) Shear viscosity η s (F) First normal stress difference N1, (G) tensile stress σ at the sharp contraction section immediately before the molding die lip of the molten thermoplastic resin. e , (H) extensional viscosity η e By adjusting the molding conditions so that the result falls within a specific range, molding defects in resin molded products can be improved.

[0234] <Example 15> [Manufacturing of multilayer structures 1] A 3-type, 5-layer multilayer co-extruded cast film manufacturing apparatus was used to produce a 3-type, 5-layer multilayer structure (film) consisting of EVOH1 (ethylene structural unit content 29 mol%, degree of saponification 99.7 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g)), linear low-density polyethylene 1 (LLDPE1) [UF240 manufactured by Nippon Polyethylene Co., Ltd., MFR 2.1 g / 10 min (190°C, load 2160 g)], and a polyolefin resin containing polar groups (PLEXAR PX3236 manufactured by LyondellBasell, MFR 2.0 g / 10 min [190°C, load 2160 g]). Multilayer co-extrusion molding was performed under the following conditions to obtain a 3-type, 5-layer multilayer structure (film) consisting of one LLDPE layer, one polar group-containing PO layer, one EVOH layer, one polar group-containing PO layer, and one LLDPE layer. The thickness (μm) of each layer in the multilayer structure was 37.5 / 5 / 15 / 5 / 37.5. The die temperature of the molding machine was set to 210°C for all layers. (Multilayer co-extrusion molding conditions 1) • Intermediate extruder (EVOH): 40mmφ single-screw extruder (barrel temperature: 210℃) • Upper and lower layer extruder (LLDPE): 40mmφ single-screw extruder (barrel temperature: 210℃) • Upper and lower layer extruder (polyolefin resin containing polar groups): 32mmφ single-screw extruder (barrel temperature: 210℃) • Die: 3 types, 5 layers, feed block type T die (Die temperature: 210℃, Die lip width: 450mm, Die lip thickness: 0.5mm, Inlet angle of the sharply narrowed section just before the die lip: 60°) • Pickup speed: 9.0m / min Roll temperature: 80℃

[0235] [Shear strain rate 1S] -1 Shear viscosity η s , and extensional strain rate 1S -1 Extensional viscosity η e How to find it] By using the melt property calculation apparatus, melt property calculation method, and computer program according to this embodiment, the shear strain rate 1S at the molding temperature of a multilayer structure can be calculated. -1 Shear viscosity η s , and extensional strain rate 1S -1 Extensional viscosity η eWe calculated each of them.

[0236] The multilayer structure obtained above was visually evaluated based on the evaluation criteria shown below. The evaluation results are shown in Table 2 below. [Evaluation Criteria] A; Very good B; Good C; Acceptable D; bad E; Very bad

[0237] <Example 16> In Example 15, a multilayer structure was fabricated in the same manner as in Example 15, except that linear low-density polyethylene 2 (LLDPE2) [GS650, manufactured by ENEOS NUC, MFR 0.7 g / 10 min (190°C, load 2160 g)] was used instead of LLDPE1. The appearance of the obtained multilayer structure was evaluated in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0238] <Example 17> In Example 15, a multilayer structure (film) was fabricated in the same manner as in Example 15, except that the thickness (μm) of each layer of a three-type, five-layer structure consisting of one LLDPE layer, one polar group-containing PO layer, one EVOH layer, one polar group-containing PO layer, and one LLDPE layer was set to 17 / 5 / 15 / 5 / 58. The appearance of the obtained multilayer structure was evaluated in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0239] <Example 18> In Example 17, a multilayer structure was fabricated in the same manner as in Example 17, except that linear low-density polyethylene 2 (LLDPE2) [GS650, manufactured by ENEOS NUC, MFR 0.7 g / 10 min (190°C, load 2160 g)] was used instead of LLDPE1. The appearance of the obtained multilayer structure was evaluated in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0240] <Example 19> In Example 15, a multilayer structure (film) was fabricated in the same manner as in Example 15, except that the thickness (μm) of each layer of a three-type, five-layer structure (film) consisting of one LLDPE layer, one polar group-containing PO layer, one EVOH layer, one polar group-containing PO layer, and one LLDPE layer was set to 8.5 / 5 / 15 / 5 / 66.5. The appearance of the obtained multilayer structure was evaluated in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0241] <Example 20> [Manufacturing of multilayer structures 2] A 3-type, 5-layer multilayer co-extrusion cast film manufacturing apparatus was used to produce a multilayer structure (film) consisting of EVOH4 (ethylene structural unit content 32 mol%, degree of saponification 99.7 mol%, MFR 12 g / 10 min (210°C, load 2160 g)), linear low-density polyethylene 1 (LLDPE1) [UF240, manufactured by Nippon Polyethylene Co., Ltd., MFR 2.1 g / 10 min (190°C, load 2160 g)], and a polyolefin resin containing polar groups (PLEXAR PX3236, manufactured by LyondellBasell, MFR 2.0 g / 10 min [190°C, load 2160 g]). Multilayer co-extrusion molding was performed under the following conditions to obtain a 3-type, 3-layer structure (film) consisting of an EVOH4 layer, a polar group-containing PO layer, and an LLDPE1 layer. The thickness (μm) of each layer of the multilayer structure was 15 / 5 / 80. The die temperature of the molding apparatus was set to 210°C for all layers. (Multilayer co-extrusion molding conditions 2) • Upper extruder (EVOH): 40mmφ single-screw extruder (barrel temperature: 210℃) • Mid-layer extruder (polyolefin resin containing polar groups): 32mmφ single-screw extruder (barrel temperature: 210℃) • Lower layer extruder (LLDPE): 40mmφ single-screw extruder (barrel temperature: 210℃) • Die: 3 types, 5 layers, feed block type T die (Die temperature: 210℃, Die lip width: 450mm, Die lip thickness: 0.5mm, Inlet angle of the sharply narrowed section just before the die lip: 60°) • Pickup speed: 9.0m / min Roll temperature: 80℃ The appearance evaluation of the multilayer structure obtained above was carried out in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0242] <Comparative Example 12> In Example 20, a multilayer structure was fabricated in the same manner as in Example 15, except that linear low-density polyethylene 2 (LLDPE2) [GS650, manufactured by ENEOS NUC, MFR 0.7 g / 10 min (190°C, load 2160 g)] was used instead of LLDPE1. The appearance of the obtained multilayer structure was evaluated in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0243] <Comparative Example 13> In Example 20, a multilayer structure was prepared in the same manner as in Example 15, except that EVOH1 (ethylene structural unit content 29 mol%, degree of saponification 99.7 mol%, MFR 3.8 g / 10 min (210°C, load 2160 g)) was used instead of EVOH4, and linear low-density polyethylene 2 (LLDPE2) [ENEOS NUC "GS650", MFR 0.7 g / 10 min (190°C, load 2160 g)] was used instead of LLDPE1. The appearance of the obtained multilayer structure was evaluated in the same manner as in Example 15. The evaluation results are shown in Table 2 below.

[0244] [Table 2]

[0245] From the results in Table 2, the multilayer structures of Examples 15-20 had excellent appearance. Therefore, the position of the lamination interface between the EVOH layer and the polar group-containing PO layer closest to the die lip wall surface in the molded die lip portion of the molten thermoplastic resin, and / or the position of the lamination interface between the polyamide layer and the polar group-containing PO layer, satisfies formula (22), and the shear strain rate of 1S at the molding temperature of the multilayer structure of the EVOH layer and / or polyamide layer and PO layer is excellent. -1 (E) Shear viscosity η s [Pa s] and extensional strain rate 1S -1 (H) Extensional viscosity η eBy adjusting the molding conditions so that [Pa s] satisfies equation (23), molding defects in the resin molded product can be improved. [Industrial applicability]

[0246] The physical property calculation method, physical property calculation apparatus, and computer program according to this embodiment can simultaneously determine the melt properties necessary to improve various molding defects (dimensional defects, strength defects, shape defects, appearance defects, etc.) of a resin molded article containing at least one type of thermoplastic resin, under multiple conditions (temperature, resin type, etc.). Therefore, it is possible to support the determination of design conditions for packaging materials that are free from various molding defects such as appearance defects. Furthermore, resin molded articles manufactured using the molding defect improvement method according to this embodiment are free from molding defects such as appearance defects. Therefore, these resin molded articles are useful as packaging materials and containers for various products, including general foods, condiments such as mayonnaise and dressings, fermented foods such as miso, oily foods such as salad oil, beverages, cosmetics, and pharmaceuticals. [Explanation of Symbols]

[0247] 1. Resin molded body 2. First thermoplastic resin 3. Second thermoplastic resin 4. Third thermoplastic resin 5. First thermoplastic resin layer 6. Second thermoplastic resin layer 7. Third thermoplastic resin layer

Claims

1. A melting property calculation device for calculating the melting properties when forming a resin molded article containing at least one type of thermoplastic resin, comprising: a receiving means for receiving at least one variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions; a recording means for which specific parameters for each type of thermoplastic resin are recorded; and a calculation means for calculating at least one melting property selected from (A) to (H) below, based on the variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions received by the receiving means and the specific parameters for each type of thermoplastic resin recorded in the recording means. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G'' [Pa] (C) Complex viscosity | η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N 1 [Pa] (G) Elongation stress σ e [Pa] (H) Elongation viscosity η e [Pa s]

2. The melt property calculation apparatus according to claim 1, wherein the resin molded body is a multilayer structure having two or more thermoplastic resin layers made of a resin composition containing at least one thermoplastic resin.

3. The melt property calculation apparatus according to claim 1 or 2, wherein the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin that does not contain polar groups, a polyolefin resin that contains polar groups, an ethylene-vinyl alcohol resin, and a polyamide resin.

4. A method for calculating melt properties when forming a resin molded article containing at least one type of thermoplastic resin, using the melt property calculation apparatus described in claim 1, the method comprising a step of calculating at least one type of melt property selected from (A) to (H) below, based on the type of thermoplastic resin, at least one variable or arbitrary constant relating to molding conditions, and intrinsic parameters for each type of thermoplastic resin. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G'' [Pa] (C) Complex viscosity | η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N 1 [Pa] (G) Elongation stress σ e [Pa] (H) Elongation viscosity η e [Pa s]

5. The method for calculating melt properties according to claim 4, wherein the resin molded article is a multilayer structure having two or more thermoplastic resin layers made of at least one type of thermoplastic resin.

6. The method for calculating melt properties according to claim 4 or 5, wherein the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin that does not contain polar groups, a polyolefin resin that contains polar groups, an ethylene-vinyl alcohol resin, and a polyamide resin.

7. A computer program for calculating melt properties when forming a resin molded article containing at least one type of thermoplastic resin, using the melt property calculation device described in claim 1, the computer program for executing the following steps: inputting at least one variable or arbitrary constant relating to the type of thermoplastic resin and molding conditions into the melt property calculation device to obtain the intrinsic parameters of the input type of thermoplastic resin from the intrinsic parameters for each type of thermoplastic resin recorded in the melt property calculation device in advance; and causing the melt property calculation device to calculate at least one melt property selected from (A) to (H) below based on the obtained intrinsic parameters of at least one type of thermoplastic resin and the variables or arbitrary constant relating to molding conditions. (A) Storage modulus G' [Pa] (B) Loss modulus of elasticity G'' [Pa] (C) Complex viscosity | η * | [Pa s] (D) Shear stress σ s [Pa] (E) Shear viscosity η s [Pa s] (F) First normal stress difference N 1 [Pa] (G) Elongation stress σ e [Pa] (H) Elongation viscosity η e [Pa s]

8. The computer program according to claim 7, wherein the resin molded article is a multilayer structure having two or more thermoplastic resin layers containing at least one type of thermoplastic resin.

9. The computer program according to claim 7 or 8, wherein the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin that does not contain polar groups, a polyolefin resin that contains polar groups, an ethylene-vinyl alcohol resin, and a polyamide resin.

10. A method for improving molding defects in a resin molded article, which uses the melt property calculation apparatus described in claim 1 to improve molding defects in the resin molded article.

11. A method for improving molding defects in a resin molded article, which improves molding defects in a resin molded article using the molten physical properties calculation method described in claim 4.

12. A method for improving molding defects in a resin molded article, which involves using the computer program described in claim 7 to improve molding defects in the resin molded article.

13. The method for improving molding defects in a resin molded article according to any one of claims 10 to 12, wherein the method for improving molding defects in a resin molded article satisfies all of the following conditions. [conditions] (D) Shear stress σ on the wall surface of the molded die lip of a molten thermoplastic resin s (E) Shear viscosity η s (F) First normal stress difference N 1 The pressure ranges from 100 to 2,000,000 Pa. (G) Elongation stress σ in the sharp contraction section immediately before the molding die lip of the molten thermoplastic resin e (H) Extensional viscosity η e The range is 90 to 9,000,000 Pa s.

14. The resin molded article is a multilayer structure in which a polyolefin resin layer (d) that does not contain polar groups is laminated on at least one side of an ethylene-vinyl alcohol resin layer (a) and / or a polyamide layer (c) via a polyolefin resin layer (b) that contains polar groups. The molding defect improvement method is such that the position of the lamination interface (A / B) between the ethylene-vinyl alcohol resin layer (A) closest to the molded die lip wall surface and the polyolefin resin layer (B) containing polar groups, and / or the position of the lamination interface (C / B) between the polyamide layer (C) and the polyolefin resin layer (B) containing polar groups, satisfies the following formula (22), and the shear strain rate of 1S at the molding temperature of the multilayer structure of the ethylene-vinyl alcohol resin layer (A) and / or the polyamide layer (C) and the polyolefin resin layer (D) that does not contain polar groups. -1 (E) Shear viscosity η s , and extensional strain rate 1S -1 (H) Extensional viscosity η e However, the molding defect improvement method according to any one of claims 10 to 12 satisfies the following formula (23). 0.2 ≤ {(distance from the molded die lip wall of the laminate interface (A / B) and / or laminate interface (C / B)) / (thickness of the molded die lip)} ≤ 0.8 ... (22) 0.5 ≤ {(η e / η s ) e / (η e / η s ) a} ≤ 4.5 and / or 0.5 ≤ { (η e / η s ) e / (η e / η s ) ≤ 4.5 ... (23)

15. A resin molded article obtained using a molten physical property calculation apparatus, a molten physical property calculation method, a computer program, and a method for improving molding defects of a resin molded article, as described in any one of claims 1, 4, 7, 10 to 12.

16. A method for manufacturing a resin molded article, comprising using a molten property calculation apparatus, a molten property calculation method, a computer program, and a molding defect improvement method according to any one of claims 1, 4, 7, 10 to 12.

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