Mold, method for manufacturing a plate-shaped molded article, method for manufacturing a test piece, and method for predicting properties of a molded article of a resin composition

Abstract

Provided is a mold capable of easily manufacturing a test piece in which the orientation direction of a filler material is highly uniform, a method for manufacturing a sheet-shaped molded article, and a method for manufacturing a test piece. Also provided is a method for predicting the properties of a molded article of a resin composition, in which the anisotropic property values of a resin composition can be measured using the test piece, and the property values are used in computer analysis to improve prediction accuracy. In more detail, a mold (1) for injection molding a sheet-shaped molded article using a melt of a thermoplastic resin, wherein the mold is provided with a runner portion (12) having a slit-shaped gate portion (13) disposed along the width direction of the sheet-shaped molded article, and configured to fill the melt injected through a straight gate portion (11) in a cavity through the slit-shaped gate portion. The runner portion branches the melt from the straight gate portion, and causes the branched melt to flow together at a portion along the slit-shaped gate portion, and guides the melt after flowing together toward the slit-shaped gate portion.

Description

Technical Field

[0001] This disclosure relates to a method for manufacturing a mold, a method for manufacturing a sheet-shaped molded article, a method for manufacturing a test piece, and a method for predicting the properties of molded articles of resin compositions. Background Technology

[0002] In recent years, resin materials, represented by engineering plastics, which have the characteristics of high productivity, excellent formability, lightweight and high heat resistance, have been widely used in motors, electronics, conveying equipment parts, building materials and other applications.

[0003] In such resin materials, fillers are often added to impart the necessary properties. Hereinafter, strength will be used as an example of a property, but properties are not limited to strength; rather, they refer to all properties imparted and reinforced by the filler, such as other mechanical and physical properties, electrical conductivity, and thermal conductivity. Most generally, rod-shaped micro-reinforcing materials are added to increase strength. Representative examples include glass fiber and carbon fiber. For resin materials containing such reinforcing materials, it is generally known that if the direction in which the property is measured differs from the orientation direction of the reinforcing material, the property value changes; this is called the "anisotropy" of strength. For example, tensile strength is greatest in the direction where the reinforcing material is fully oriented and lowest in the direction perpendicular to it.

[0004] In product design, computer-based analysis is used to predict the product's strength and durability. The material properties (physical properties) used in such calculations are determined to be a single value for homogeneous materials like metals. However, in products made of resin materials containing reinforcing materials, the orientation of the internal reinforcing materials is non-uniform, resulting in different properties depending on their location. In such cases, the orientation direction of the reinforcing materials is calculated in the analysis, and various properties corresponding to that direction are also calculated, thus taking into account the effects of anisotropy.

[0005] Therefore, data on the correlation between orientation and various properties are important. However, the typical shape of test pieces used for measurement is a rectangular shape that is longer in one direction, such as a dumbbell shape, making it almost impossible to freely change the orientation. Therefore, a plate is fabricated with the reinforcing material oriented in one direction, the angle relative to the orientation direction is changed, and test pieces are cut out to measure the properties of the test pieces.

[0006] However, in actual injection-molded flat sheets, orienting the reinforcing material in one direction is extremely difficult, making it impossible to obtain useful data. This is because the resin within the mold also flows laterally, a point also pointed out by Autodesk, the developer of the flow analysis software. (Reference: Autodesk, AUTODESK UNIVERSITY 2013 Modeling of Fiber Orientation and Fiber Length: Modeling in the Context of Computational Methods, https: / / download.autodesk.com / temp / pdf / simday2013_002.pdf)

[0007] Regarding the above, Patent Document 1 discloses a mold used in a resin forming method that improves the orientation of the filler material by using a barrier member.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2009-226841 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, in the method of Patent Document 1, an additional obstruction component is required, which raises the possibility that the required length of the test piece cannot be ensured in materials with poor flowability.

[0013] This disclosure was made in view of the above circumstances, and its object is to provide a mold for easily manufacturing test pieces with highly consistent orientation directions of filler materials, a method for manufacturing plate-shaped molded articles, and a method for manufacturing test pieces. Furthermore, another object of this disclosure is to provide a method for predicting the properties of molded articles of resin compositions, in which the test piece can be used to measure the anisotropic property values ​​of the resin composition, and these property values ​​can be used for computer analysis to improve prediction accuracy.

[0014] Solution for solving the problem

[0015] One embodiment of the mold disclosed herein is used for injection molding sheet-like articles using molten thermoplastic resin, wherein...

[0016] The mold includes a runner section having a slit-shaped gate section disposed along the width direction of the plate-shaped molded article, and is configured such that the molten material injected through the sprue section fills the cavity through the slit-shaped gate section.

[0017] The runner section branches the molten material from the sprue section and causes it to merge along a portion of the slit gate section, guiding the merged molten material toward the slit gate section.

[0018] A method for manufacturing a plate-shaped molded article according to one embodiment of the present disclosure includes,

[0019] The process of using the mold described above to fill the cavity with the fused molten material through the slit-shaped gate.

[0020] A method for manufacturing a test piece according to one embodiment of this disclosure includes,

[0021] The process of cutting out test pieces from a plate-shaped article manufactured using the above-described method along at least one angle in the range of 0° to 90° relative to the flow direction.

[0022] The method for predicting the properties of molded articles of resin compositions according to one embodiment of this disclosure includes,

[0023] A process for measuring the characteristics of a test piece manufactured using the above-described test piece manufacturing method.

[0024] Furthermore, one embodiment of the method for predicting the properties of molded articles of resin compositions disclosed herein includes,

[0025] The process of calculating the properties of molded articles of resin compositions different from those of the test piece based on the measured properties of the test piece.

[0026] The effects of the invention

[0027] According to this disclosure, a mold for easily manufacturing test pieces with highly consistent orientation directions of filler materials, a method for manufacturing plate-shaped molded articles, and a method for manufacturing test pieces can be provided. Furthermore, according to this disclosure, a method for predicting the properties of molded articles of resin compositions can be provided, in which the test piece can be used to measure the anisotropic property values ​​of the resin composition, and these property values ​​can be used for computer analysis to improve prediction accuracy. Attached Figure Description

[0028] Figure 1 This is a perspective view of a mold according to one embodiment of the present disclosure.

[0029] Figure 2 yes Figure 1 A cross-sectional view of the runner section of the mold.

[0030] Figure 3 This is a diagram used to illustrate the cut-out of the test piece.

[0031] Figure 4This is a diagram showing the flow of resin in an existing mold.

[0032] Figure 5 This is a diagram showing the flow of resin in an existing mold.

[0033] Figure 6 It is a schematic diagram illustrating the fracture surface of the test piece.

[0034] Figure 7 This is a microscope image of the fracture surface of the test piece obtained in Example 4.

[0035] Figure 8 These are microscope images of the fracture surface of the test piece obtained in Comparative Example 4. Detailed Implementation

[0036] (Mold)

[0037] Hereinafter, a mold 1 according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. In the drawings used in the following description, there are cases where the shapes and dimensional relationships of the elements shown differ from those in the actual mold 1.

[0038] Figure 1 This is a perspective view of the mold 1 in this embodiment. Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the runner section 12 of mold 1. Mold 1 is used to injection mold a sheet-like article 20 (see reference) from a melt of a resin composition consisting of a mixed thermoplastic resin and an anisotropic filler material. Figure 3 The resin composition is, for example, a polyarylene sulfide (PAS) resin composition. A PAS resin composition is a mixture of PAS resin and a fibrous filler material.

[0039] The mold 1 includes: a sprue section 11 for initial injection of molten resin composition (hereinafter referred to as "molten material"); a runner section 12 having a slit-shaped gate section 13; and a forming section 14 having an internal cavity 15 for forming a plate-shaped molded article 20. The sprue section 11 and the runner section 12 are flow paths for the molten resin composition to flow within them. In this disclosure, as... Figure 1 As shown, the flow direction (MD: Machine Direction) is defined as the direction in which the resin flows within the molding section 14. Furthermore, the flow direction is perpendicular to the length direction of the slit-shaped gate section 13. Here, the cavity 15 is a hollow portion for the molten material to fill.

[0040] In this embodiment, the sprue section 11 has a hollow pipe shape with a circular cross-section. However, the sprue section 11 is not limited to this shape. A portion of the hollow part of the sprue section 11 is connected to the hollow part of the runner section 12, and the molten material flowing through the sprue section 11 is injected into the runner section 12. In this embodiment, when viewed along the flow direction, the sprue section 11 and the runner section 12 intersect at right angles. However, the connection between the sprue section 11 and the runner section 12 is not limited to this.

[0041] like Figure 2 As shown, the runner section 12 has a slit-shaped gate section 13 provided along the width direction of the formed plate-shaped molded article 20. Here, the width direction of the plate-shaped molded article 20 is parallel to the direction perpendicular to the flow direction (TD: Transverse Direction). The runner section 12 is configured such that the molten material injected through the sprue section 11 fills the cavity 15 through the slit-shaped gate section 13.

[0042] In the runner section 12, the molten material from the sprue section 11 branches and merges along the slit gate section 13 (merging region 16), guiding the merged molten material towards the slit gate section 13. Figure 2 As shown, in the runner section 12, the molten material from the sprue section 11 is first branched in two directions. The branched molten material merges towards the center from both sides in a direction perpendicular to the flow direction in the merging region 16. The merged molten material is extruded into the slit-shaped gate section 13 and injected into the cavity 15 from the slit provided in the slit-shaped gate section 13.

[0043] In the runner section 12, the molten material branches and merges in the confluence region 16 along the slit-shaped gate section 13. With the aforementioned structure, the TD component of the flowing molten material guided towards the slit-shaped gate section 13 is offset or at least attenuated. That is, for the molten material filling the cavity 15, the TD component of the flowing material is attenuated while maintaining the MD component, and it passes through the slit-shaped gate section 13. Therefore, the molten material filling the cavity 15 becomes molten material with the orientation direction of the filler material along the flow direction. Particularly for the central portion of the slit-shaped gate section 13, the TD component of the molten material flowing from both ends of the slit-shaped gate section 13 is offset. Therefore, for the central portion in the width direction of the plate-shaped molded article 20, the orientation direction of the filler material is particularly along the flow direction.

[0044] Here, existing molds guide the molten material toward the gate without causing it to branch. A representative example is... Figure 4 , Figure 5 That kind of structure.

[0045] Figure 4It has a similar structure to confluence region 16, but produces flow from the central part to the left and right. Additionally, in Figure 5 In the process, radial flow is generated from the sprue section 11. Therefore, flow extending in the width direction is generated in the cavity 15, and the orientation direction of the filling material is inconsistent in the molded article.

[0046] In this embodiment, the runner section 12 is approximately quadrilateral in shape, and on the side where the slit-shaped gate section 13 is located ( Figure 2 The opposite side (below) Figure 2 The upper part of the runner 12 is connected to the central portion of the sprue 11. Here, the runner 12 is not limited to a quadrilateral shape; for example, it can be triangular. In this case, a slit-shaped gate 13 can be provided at the base of the triangle, and the sprue 11 can be connected to the apex. Here, in order to offset the TD component of the melt at the central portion of the slit-shaped gate 13, it is preferable that... Figure 2 In the cross-sectional view shown, the sprue section 11 is positioned on the vertical bisecting line of the slit-shaped gate section 13. However, the position of the sprue section 11 connected to the runner section 12 is not limited to this. In this embodiment, the slit-shaped gate section 13 is thinner than the portion of the runner section 12 other than the slit-shaped gate section 13, but other arrangements are also possible.

[0047] Alternatively, an venting channel can be provided in the runner section 12 at a position opposite to the slit-shaped gate section 13, separated from the confluence region 16. By providing an venting channel, the thermal degradation of the material caused by adiabatic compression due to air in the mold 1 and gases generated from the material can be suppressed.

[0048] In this embodiment, the slit-shaped gate portion 13 is constructed as a thin-film gate. The thin-film gate has a portion that is thinner than the cavity 15, but it can also be of other types. However, the thickness of the gate needs to be thinner than the thickness of the runner; if it is too thick, the molten material will flow into the cavity 15 before the confluence region 16 is filled, which will worsen the effect of consistent orientation.

[0049] The forming section 14 has a cavity 15 for filling with molten material to form the plate-shaped molded article 20. The size of the cavity 15 (i.e., the size of the plate-shaped molded article 20) can be, for example, TD and MD of 100 mm each. The size of the cavity 15 is not limited to this and can also be rectangular.

[0050] (Manufacturing method for plate-shaped molded articles)

[0051] The plate-shaped molded article 20 can be manufactured using the mold 1 described above and by injection molding. The method for manufacturing the plate-shaped molded article 20 includes a step of filling the cavity 15 with the fused molten material through the slit-shaped gate 13 using the mold 1. In addition to this, the method for manufacturing the plate-shaped molded article 20 may also include known steps performed in injection molding. As described above, for the plate-shaped molded article 20 manufactured by the method of this embodiment, the orientation direction of the filling material in the central portion in its width direction is particularly along the flow direction. In this embodiment, the plate-shaped molded article 20 serves as the material for the test piece 30, but its use is not limited to this purpose. The plate-shaped molded article 20 can be, for example, a plate-shaped product such as building material or packaging material.

[0052] The orientation tensor of the filler at the center of the wall thickness in the MD direction (flow direction) of the central portion of the plate-shaped molded article 20 in the width direction is preferably 0.60 or more and preferably 0.95 or less. The orientation tensor can be obtained by the following method: as in the embodiment, the center portion (wall thickness center) of the sample cut from the center of the plate-shaped molded article in the thickness direction is photographed using a three-dimensional measuring X-ray CT device, and the angle between the MD direction and the filler is measured based on the photographed image.

[0053] (Manufacturing method of the experimental piece)

[0054] Test pieces 30 can be manufactured by cutting them out from the plate-shaped molded article 20. The method for manufacturing test pieces 30 includes the step of cutting test pieces 30 from the plate-shaped molded article 20 at at least one angle in the range of 0° to 90° relative to the flow direction. Figure 3 This is a diagram illustrating the cutout of the test piece 30. As described above, for the central portion in the width direction of the plate-shaped molded article 20, the orientation direction of the filler material is particularly along the flow direction. Figure 3 As shown, the test piece 30 is cut out in a manner that includes the center portion of the plate-shaped molded article 20. The test piece 30 is, for example, dumbbell-shaped, but is not limited to that shape. Figure 3 As shown, in this embodiment, the angle between the test piece 30 and the flow direction is the angle formed by the flow direction and the length direction of the test piece 30. From Figure 3 Starting from the left side, cut out test pieces 30 at angles of 0°, 45°, and 90° relative to the flow direction.

[0055] The cut test piece 30 has a central portion with a particularly consistent orientation of the filler material. Properties such as strength are obtained by measuring the central portion of the test piece. Therefore, this characteristic is particularly useful. Evaluating such a test piece 30 and applying the measured characteristic data of the test piece 30 to CAE (Computer-Aided Engineering) analysis of injection-molded articles allows for the prediction of product characteristics with greater accuracy than currently possible.

[0056] (Methods for predicting the properties of molded articles from resin compositions)

[0057] The properties of the molded article of the resin composition can be predicted using the measured properties of the aforementioned test piece 30. Here, properties may refer to mechanical properties such as strength and modulus of elasticity, but are not limited to these; they may also be material properties or physical properties such as electrical conductivity and thermal conductivity. Furthermore, in this disclosure, prediction means that at least a portion is calculated rather than measured. The method for predicting the properties of the molded article of the resin composition includes: a step of measuring the properties of the aforementioned test piece 30; and a step of calculating the properties of the molded article of the resin composition, which differs from those of the test piece 30, based on the measured properties of the test piece 30. In addition to this, the method for predicting the properties of the molded article of the resin composition may also include known steps performed in the property prediction.

[0058] The method for predicting the properties of molded articles of resin compositions is divided into: product property prediction processing, which predicts the properties of the product as a molded article of the resin composition, and benchmark data acquisition processing, which obtains the benchmark data used in the product property prediction processing. The benchmark data acquisition processing is performed before the product property prediction processing. The step of measuring the properties of the test piece 30 is performed as one step of the benchmark data acquisition processing. The step of calculating the properties of the molded article of the resin composition is performed as one step of the product property prediction processing.

[0059] (Benchmark data acquisition and processing)

[0060] The reference data includes data for any angle between 0° and 90°. To improve the accuracy of product characteristic prediction processing, it is preferable to include data on the characteristics of the test piece 30 at angles between 0° and 90°, such as 45°, in the reference data. As a process for measuring the characteristics of the test piece 30, the characteristics are measured. The measurement results are incorporated as reference data into a computer simulation for CAE analysis.

[0061] In this embodiment, computer simulation can analyze not only the properties of the molded article (such as strength), but also deformation caused by shrinkage or warping of the molded article, residual stress of the molded article, and orientation of the fibrous filler material. As described above, compared to the prior art, test pieces 30 are cut from the plate-shaped molded article 20 along the flow direction from the orientation direction of the filler material. Therefore, by using the data of the characteristics of the test piece 30 as reference data, the predicted characteristics of the product based on the analysis results of computer simulation are more accurate than before.

[0062] In the aforementioned computer simulation, known supplementary techniques can be used to calculate characteristics of angles not present in the baseline data. Alternatively, a predictive model can be used in the computer simulation, with the generation of the predictive model incorporating at least the characteristic data of the test piece 30 at the angle required by the implementer. The angle required by the implementer may, for example, include 0° and 90°. The predictive model can be generated through machine learning using the characteristic data of the test piece 30 as training data.

[0063] (Product Feature Prediction Processing)

[0064] Computer simulation acquires structural information of the product as a molded article of the resin composition after baseline data acquisition and processing. This structural information can be obtained, for example, by reading a 3D model from a CAD (Computer-Aided Design) application. Then, a finite element model can be generated, for example, by performing mesh generation based on the finite element method. Furthermore, flow analysis and orientation analysis of the melt during injection molding of the product can be performed. Following such analysis, characteristics are calculated using the baseline data in conjunction with the product's orientation. In other words, the process of calculating the characteristics of the molded article of the resin composition is performed.

[0065] In product characteristic prediction processing, the strength of various parts of the product can be calculated based on the calculated product characteristics, and the extent to which it can withstand loads in which directions can be predicted. The calculated characteristic values ​​and the prediction results based on the characteristics can be displayed to the computer-simulated executor.

[0066] In addition to computer simulation, product characteristic prediction processing can also utilize materials informatics (MI) that analyzes data using machine learning, artificial intelligence (AI), and other methods. In this case, the baseline data obtained through the aforementioned methods can be used as learning data (teaching data).

[0067] (Resin Composition)

[0068] The aforementioned sheet-shaped molded article 20 is formed from a resin composition obtained by mixing a thermoplastic resin and a filler material. In this embodiment, there are no particular limitations on the thermoplastic resin; examples include: polyolefin resins such as polyethylene, polypropylene, poly(4-methyl-1-pentene), and poly(1-butene); polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamide resins such as polyamide-6 (nylon-6), polyamide-66 (nylon-66), and poly(m-phenylene adipamide); ethylene / unsaturated ester copolymers such as ethylene / vinyl ester copolymers and ethylene / unsaturated carboxylic acid ester copolymers; and ethylene / unsaturated carboxylic acid ester copolymers. Acid-based copolymers or their ionomers; poly(meth)acrylate resins such as poly(meth)acrylate resins; chlorine-based resins such as polyvinyl chloride and polyvinylidene chloride; fluorine-based resins such as polytetrafluoroethylene, ethylene tetrafluoroethylene copolymers, polyvinylidene fluoride, and polyvinylidene fluoride; polystyrene resins; polyether ether ketone resins and polyether ketone resins; polycarbonate resins; polyaryl sulfide resins, represented by polyphenylene sulfide resins, and polyphenylene ether resins; polyvinyl acetate resins; polyacrylonitrile resins; thermoplastic elastomers; liquid crystal polymers (LCPs), etc. Furthermore, one of the above-mentioned thermoplastic resins can be used alone, or in combination of two or more.

[0069] In this embodiment, there are no particular limitations on the filler material having a shape that allows it to be oriented when the thermoplastic resin softens and flows within the mold. Examples of fillers with aspect ratios include fibrous or needle-like fillers, granular or plate-like non-fibrous fillers, and organic or inorganic fillers. Fibrous fillers are preferred. Specifically, examples include fibrous fillers such as glass fiber, carbon fiber, aramid fiber, potassium titanate, calcium silicate, wollastonite, natural fiber, and abrasive fiber. Non-fibrous fillers include barium sulfate, clay, pyrophyllite, bentonite, sericite, mica, talc, palygorskite, ferrite, calcium silicate, calcium carbonate, magnesium carbonate, zeolite, and calcium sulfate. The fillers have aspect ratios in the range of approximately 2 to 100. Here, the aspect ratio (the ratio of the longest length (major axis) to the shortest length (minor axis) when made into a two-dimensional image) is not particularly limited, but is preferably 2 or more, more preferably 2 or more, and no upper limit is set, but is preferably 100 or less, more preferably 50 or less. The mixing ratio of the filler material relative to 100 parts by weight of thermoplastic resin is preferably in the range of 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, and no upper limit is set, but is preferably in the range of 600 parts by weight or less, more preferably 250 parts by weight or less.

[0070] Although the resin composition is formed by mixing thermoplastic resin and filler as essential components, other commonly known additives such as colorants, antistatic agents, antioxidants, heat stabilizers, UV stabilizers, UV absorbers, foaming agents, flame retardants, flame retardant additives, rust inhibitors, and coupling agents may also be mixed as optional components as needed. These additives are not essential components; for example, they may be used in appropriate amounts according to purpose and application, preferably in the range of 0.01 parts by weight or more and preferably less than 100 parts by weight relative to 100 parts by weight of thermoplastic resin, without impairing the effects of this disclosure.

[0071] The method for manufacturing the resin composition includes the following steps: mixing a thermoplastic resin and a filler as necessary components, and performing melt mixing in a temperature range above the temperature at which the thermoplastic resin softens and flows upon heating (which may be the melting point in the case of crystalline resin, or the glass transition temperature in the case of amorphous resin; hereinafter referred to as "softening flow temperature").

[0072] The resin composition is formed by mixing the necessary components and, as needed, any other arbitrary components. There are no particular limitations on the method of manufacturing the resin composition; examples include mixing the necessary components and, as needed, mixing any other components and then performing melt mixing. More specifically, examples include dry mixing using a roller or Henschel mixer, and then feeding the mixture into a twin-screw extruder for melt mixing.

[0073] Melt mixing can be performed by heating the resin to a temperature range above the softening flow temperature of the thermoplastic resin, preferably above the softening flow temperature +10°C, more preferably above the softening flow temperature +20°C, preferably below the softening flow temperature +100°C, and more preferably below the softening flow temperature +50°C. For example, the temperature range can be determined based on the ease of softening flow of the thermoplastic resin as the base resin, from preferably above 100°C, more preferably above 120°C, more preferably above 150°C, and preferably below 400°C, more preferably below 380°C, and more preferably below 350°C.

[0074] Preferably, for the resin composition, after the melt mixing, it is processed into pellets, flakes, granules, powders, etc. by a known method, such as extruding the molten resin composition in strands, and then pre-drying is performed as needed.

[0075] The resin composition thus obtained can be used to manufacture the aforementioned sheet-shaped molded articles and test pieces. For example, in an injection molding machine, the resin composition is softened and molten by heating it at a temperature range above the flow temperature of the thermoplastic resin, preferably above the softening flow temperature +10°C, more preferably above the softening flow temperature +20°C, preferably below the softening flow temperature +100°C, more preferably below the softening flow temperature +50°C, for example, within a range preferably above 100°C, more preferably above 120°C, more preferably above 150°C, and preferably below 400°C, more preferably below 380°C, more preferably below 350°C, depending on the ease of softening and flowing of the thermoplastic resin as the base resin. The molten material is injected into the aforementioned mold 1.

[0076] The above describes the use of a melt of a resin composition to manufacture plate-shaped molded article 20 and test piece 30.

[0077] In this embodiment, the results obtained by the characteristic prediction method can also be applied to the commercialization of molded articles (so-called mass production). For example, at least a portion of the materials and manufacturing process can be designed using computer simulations capable of performing the characteristic prediction method, so that the product (shape) has the desired characteristics. Material design can include adding filler materials to compensate for insufficient strength, controlling the composition of each material in the resin composition, etc. Manufacturing process design can include the design of the mold used when melt-molding the resin composition to manufacture the molded article, but is not limited to this. In particular, mold design can include changes to the mold shape to control the fiber orientation favorable to load-bearing by changing the position of the resin inlet (gate) towards the product portion, and changes to the product shape to increase strength by increasing the product wall thickness.

[0078] By utilizing it in this way, the number of prototypes required during productization can be significantly reduced, thereby further improving productivity.

[0079] Here, the product, typically a molded article of a resin composition, is not particularly limited and can be any injection-molded article. However, examples include pipes, liners, cap nuts, pipe fittings (elbows, manifolds, reducers, connectors, etc.), various valves, flow meters, gaskets (sealants, washers), and other piping and components associated with piping used for transporting fluids. Therefore, examples include automotive parts and other components associated with internal combustion engines, such as various pipes related to fuel / exhaust / intake systems, intake nozzles, vent pipes, intake manifolds, fuel pumps, engine coolant connectors, and water inlet / outlet channels, and these can also be applied to various other uses.

[0080] Example

[0081] The following description uses examples and comparative examples, but this disclosure is not limited to these examples.

[0082] (raw materials)

[0083] The raw materials used in the examples and comparative examples are as follows.

[0084] <<PAS Resin Composition>>

[0085] • DIC Corporation manufactures "Z-650-SW" (a mixture of PPS resin elastomer and 50 wt% glass fiber as a fibrous filler and filler).

[0086] <<PA Resin Composition>>

[0087] ·BASF Japan Co., Ltd.'s "ULTRAMID A3HG5" (PA resin mixed with 25wt% glass fiber)

[0088] <<PE Resin Composition>>

[0089] • A PE resin composition made by mixing 10 wt% glass fiber with "NovatecHD HJ560W" manufactured by Japan Polyethylene Co., Ltd.

[0090] (evaluate)

[0091] Dumbbell-shaped test pieces were manufactured from flat plates obtained by molding using the mold of this disclosure, and the properties of the test pieces were measured or calculated. Injection molding was performed using a Sumitomo Heavy Industries SE-75DU injection molding machine. The following mechanical properties were measured as characteristics. A small test piece conforming to ISO 1BA was used for the dumbbell shape.

[0092] Orientation parameters: The core of the dumbbell-shaped test piece was imaged using an X-ray CT scanner (Yamato Scientific Corporation, "TDM1000H-II(2K)") (image area 3mm × 3mm), obtaining a three-dimensional image of the interior of the test piece. This image was analyzed using image analysis software (Volume Graphics Corporation, "VGStudio MAX"). After separating the filler and resin phases within the image through binarization, the angle of the filler relative to the flow direction was measured, and the orientation tensor was calculated. Furthermore, an orientation tensor of 1 indicates a state where the orientation is completely aligned with the flow direction.

[0093] • Orientation Tensor: The wall thickness-average orientation tensor in the flow direction of the core at the center of the test piece is an indicator of the alignment of the fiber angle with the cutting direction, and is calculated using computer simulation of resin flow analysis (CAE). 1 indicates a state of perfect alignment. In this evaluation, the wall thickness-average orientation tensor was calculated using Moldflow Insight 2019 from Autodesk.

[0094] • Young's modulus, tensile strength, and tensile strain ISO 527-1,2 (For Type 1BA test specimens: tensile speed is 2 mm / min; for Type A test specimens: tensile speed is 5 mm / min)

[0095] (Comparison using PPS (polyphenylene sulfide) resin)

[0096] [Examples 1-2]

[0097] In Examples 1 and 2, a plate-shaped article was injection molded using the mold of this disclosure (a mold having a flow channel portion that allows the melt to converge after branching), and dumbbell-shaped test pieces were cut from the plate-shaped article. The cutting angle (the angle of the length direction of the cut test piece relative to the flow direction) in Example 1 was 0°. The cutting angle in Example 2 was 90°.

[0098] [Comparative Examples 1-2]

[0099] In Comparative Examples 1 and 2, a plate-shaped mold (equipped with a runner section that guides the molten material toward a slit-shaped gate without branching) was used to injection mold a plate-shaped article, and dumbbell-shaped test pieces were cut from the plate-shaped article. The cutting angle of Comparative Example 1 was 0°. The cutting angle of Comparative Example 2 was 90°.

[0100] [Comparative Example 3]

[0101] In Comparative Example 3, the test piece was injection molded using a mold for forming dumbbell-shaped test pieces. A dumbbell-shaped test piece is a molded article with a shape that is longer in one direction, and is generally considered to be a test piece in which the glass fibers are highly oriented almost entirely along the length direction, particularly in the narrower central portion. The fiber orientation is 0°.

[0102] [Comparative Example 4]

[0103] To clarify the situation where no weld was generated in Example 2, the following experiment was conducted as a comparative test. That is, in Comparative Example 4, a mold for forming dumbbell-shaped test pieces was used to injection mold the test pieces by allowing molten material to flow from both ends of the dumbbell shape, thereby creating a weld in the center.

[0104] The manufacturing conditions and performance evaluation results of Examples 1-2 and Comparative Examples 1-4 are shown in Table 1 below.

[0105] [Table 1]

[0106]

[0107] (Comparison using PA (polyamide) resin)

[0108] [Examples 3-4]

[0109] In Examples 3 and 4, dumbbell-shaped test pieces were cut from a plate-shaped article obtained by injection molding using the mold of this disclosure. The cutting angle in Example 3 was 0°. The cutting angle in Example 4 was 90°.

[0110] [Comparative Examples 5-6]

[0111] In Comparative Examples 5 and 6, dumbbell-shaped test pieces were cut from a plate-shaped molded article based on a prior art mold. The cutting angle in Comparative Example 5 was 0°. The cutting angle in Comparative Example 6 was 90°.

[0112] [Comparative Example 7]

[0113] In Comparative Example 7, the test piece was injection molded using a mold for forming dumbbell-shaped test pieces. The fiber orientation was 0°.

[0114] [Comparative Example 8]

[0115] In Comparative Example 8, a mold for forming dumbbell-shaped test pieces was used to injection mold the test pieces by allowing molten material to flow from both ends of the dumbbell shape to create a weld in the center.

[0116] The manufacturing conditions and performance evaluation results of Examples 3-4 and Comparative Examples 5-8 are shown in Table 2 below.

[0117] [Table 2]

[0118]

[0119] (Comparison using PE (polyethylene) resin)

[0120] [Examples 5-6]

[0121] In Examples 5 and 6, dumbbell-shaped test pieces were cut from a plate-shaped article obtained by injection molding using the mold of this disclosure. The cutting angle in Example 5 was 0°. The cutting angle in Example 6 was 90°.

[0122] [Comparative Examples 9-10]

[0123] In Comparative Examples 9 and 10, dumbbell-shaped test pieces were cut from a plate-shaped molded article based on a prior art mold. The cutting angle of Comparative Example 9 was 0°. The cutting angle of Comparative Example 10 was 90°.

[0124] [Comparative Example 11]

[0125] In Comparative Example 11, the test piece was injection molded using a mold for forming dumbbell-shaped test pieces. The fiber orientation was 0°.

[0126] [Comparative Example 12]

[0127] In Comparative Example 12, a mold for forming dumbbell-shaped test pieces was used to injection mold the test pieces by allowing molten material to flow from both ends of the dumbbell shape to create a weld in the center.

[0128] The manufacturing conditions and performance evaluation results of Examples 5-6 and Comparative Examples 9-12 are shown in Table 3 below.

[0129] [Table 3]

[0130]

[0131] Orientation photograph of (measurement) profile

[0132] The fracture surfaces of the test pieces obtained in Example 4 and Comparative Example 6 were photographed using a KEYENCE VHX-2000 digital microscope. The fracture surface was obtained by cutting the test piece along its thickness direction from its central portion (see reference XX). Figure 6 ).

[0133] The results are shown in Figure 7 , Figure 8The glass fibers (average fiber length approximately 200 micrometers, fiber diameter approximately 10 micrometers) in the test specimen were observed using a microscope. In both Example 4 and Comparative Example 6, when the flow direction of the PPS resin and the orientation direction of the glass fibers were aligned, the glass fibers were observed to be long rods (white). On the other hand, when the flow direction and the orientation direction of the glass fibers were different, the glass fibers were observed to be round (white dots), or holes (black dots) formed due to the breakage of the test specimen caused by the glass fibers detaching from the surface.

[0134] Regarding the comparative results, in Example 4, it was observed that most of the glass fibers were relatively long rods, and very few circular black spots were observed. In contrast, in Comparative Example 6, based on a mold using prior art, a few glass fibers were observed to be relatively long rods, but multiple circular black spots were observed.

[0135] In other words, it was confirmed that in Example 4, compared with Comparative Example 6, the flow direction of the filler material toward the PPS resin was more consistent.

[0136] From the comparison between Example 1 and Comparative Example 1, and further from the comparison between Example 3 and Comparative Example 5, and further from the comparison between Example 5 and Comparative Example 9, it can be seen that the test piece manufactured using the mold of this embodiment has a higher Young's modulus in the 0° direction than the test piece manufactured by the prior art, and also has higher tensile strength and smaller tensile strain.

[0137] Furthermore, a comparison between Example 3 and Comparative Example 5, and a comparison between Example 5 and Comparative Example 9, shows that the test piece manufactured using the mold of this embodiment has a higher orientation tensor in the 0° direction than the test piece manufactured by the prior art, and a larger orientation parameter. This indicates that the flow direction of the filler material phase toward the resin is more consistent.

[0138] On the other hand, in the comparison between Example 2 and Comparative Example 2, in the comparison between Example 4 and Comparative Example 6, and in the comparison between Example 6 and Comparative Example 10, the test piece manufactured using the mold of this embodiment has a lower tensile strength in the 90° direction than the test piece manufactured by the prior art.

[0139] Furthermore, regarding tensile strength and tensile strain, for Examples 1 and 2, the orientation direction of the filler material was more consistent compared to Comparative Examples 1 and 2, therefore, the difference in strength was more pronounced relative to 0°. Similarly, for Examples 3 and 4, the difference in strength was more pronounced compared to Comparative Examples 5 and 6. Likewise, for Examples 5 and 6, the difference in strength was more pronounced compared to Comparative Examples 9 and 10.

[0140] Here, based on the comparison between Example 2 and Comparative Example 4, the values ​​of tensile strain are quite different, indicating that no welding occurred in Example 2, where no significant reduction in the characteristic tensile strain value in welding was observed.

[0141] As can be clearly seen from the above comparison, the mold, plate-shaped molded article manufacturing method, and test piece manufacturing method of this embodiment can produce test pieces with highly consistent orientation directions of the filler material. Furthermore, by using test pieces with highly consistent orientation directions of the filler material, data representing the relationship between orientation angles and various properties can be measured. This acquired data can be input as the basis for predicting molded articles based on CAE. The properties of molded articles of resin compositions can be predicted with high precision using these test pieces.

[0142] Explanation of reference numerals in the attached figures

[0143] 1. Mold; 11. Sprue section; 12. Runner section; 13. Slit gate section; 14. Molding section; 15. Cavity; 16. Merging area; 20. Plate-shaped molded product; 30. Test piece.

Claims

1. A mold for injection molding a sheet-like article using a melt of a thermoplastic resin containing a filler, wherein, The mold includes a runner section having a slit-shaped gate section disposed along the width direction of the plate-shaped molded article, and is configured such that the molten material injected via the sprue section directly fills the cavity through the slit-shaped gate section. The runner section branches the molten material from the sprue section and causes it to merge at a portion along the slit-shaped gate section, guiding the merged molten material directly towards the slit-shaped gate section. After branching, the entire molten material converges from both sides toward the center in the confluence region along the slit-shaped gate, in a direction perpendicular to the flow direction, which is the direction in which the molten material flows within the cavity. The melt maintains the flow component in the flow direction while attenuating the flow component in the direction perpendicular to the flow direction, and passes through the slit-shaped gate.

2. The mold according to claim 1, wherein, The slit-shaped gate section is thinner than the runner section.

3. A method for manufacturing a plate-shaped molded article, wherein, The method for manufacturing the plate-shaped molded article includes a step of using the mold as described in claim 1 or 2 to fill the cavity with the fused molten material through the slit-shaped gate.

4. The method for manufacturing a plate-shaped molded article according to claim 3, wherein, The orientation tensor in the MD direction at the center of the wall thickness of the obtained plate-shaped molded article is in the range of 0.60 to 0.

95.

5. A method for manufacturing a test piece, wherein, The method for manufacturing the test piece includes a step of cutting the test piece from a plate-shaped article manufactured using the method for manufacturing a plate-shaped article according to claim 3 or 4 at at least one angle in the range of 0° to 90° relative to the flow direction.

6. The method for manufacturing the test piece according to claim 5, wherein, The orientation tensor in the MD direction at the center of the wall thickness of the obtained test piece is in the range of 0.60 to 0.

95.

7. A method for predicting the properties of a molded article of a resin composition, wherein, The method for predicting the properties of the molded article of the resin composition includes: A step of measuring the characteristics of a test piece manufactured using the test piece manufacturing method according to claim 5 or 6; and The process of calculating the properties of molded articles of resin compositions different from those of the test piece based on the measured properties of the test piece.

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