Thermoplastic elastomer resin composition for additive manufacturing, molded article, and method for producing same

Abstract

Provided is a molding material that exhibits an excellent balance between moldability and flexibility of a molded article, and allows hardness differences within the molded article to be increased. In one embodiment, a molded article that is an additive-manufactured article of a thermoplastic elastomer resin composition is provided, wherein the minimum value of the hardness of the molded article is 65% or less of the hardness of the thermoplastic elastomer resin composition, and the hardness is measured using a hardness tester in accordance with ISO 7619. In one embodiment, the thermoplastic elastomer resin composition contains a styrene-based elastomer and cellulose fibers.

Description

Thermoplastic elastomer resin composition for additive manufacturing, and molded objects and methods for manufacturing the same.

[0001] The present invention relates to a thermoplastic elastomer resin composition for additive manufacturing, as well as molded objects and methods for producing the same.

[0002] One additive manufacturing technology using 3D printers is the extrusion method, which involves extruding heated filament or other molding material into layers. This extrusion method has advantages such as not requiring molds for molding and offering a high degree of freedom in the shape of the molded object. For these reasons, further research and development on materials and processes have been underway in recent years.

[0003] As thermoplastic elastomer materials used in material extrusion methods, those with modified Shore A hardness (for example, Patent Document 1) and those with modified composition (for example, Patent Document 2) have been proposed.

[0004] International Publication No. 2004 / 106178, Japanese Patent Publication No. 2022-000348

[0005] However, conventional fabrication materials all have room for improvement in that they do not have a sufficient balance between fabricability and the flexibility of the fabricated object, and they cannot create large differences in hardness within the fabricated object.

[0006] In view of the level of prior art, the problem that the present invention aims to solve is to provide a molding material that offers an excellent balance between moldability and flexibility of the molded object, and that can create a large difference in hardness within the molded object.

[0007] The gist of the present invention is as follows: [1] A molded product which is an add-on of a thermoplastic elastomer resin composition, wherein the minimum hardness of the molded product is 65% or less of the hardness of the thermoplastic elastomer resin composition, and the hardness is measured by a hardness tester in accordance with ISO 7619. [2] The molded product according to item 1, wherein the thermoplastic elastomer resin composition comprises a styrene elastomer and cellulose fibers. [3] The molded product according to item 1 or 2, wherein the thermoplastic elastomer resin composition comprises an acid-modified elastomer. [4] The molded product according to any one of items 1 to 3, wherein the Shore A hardness of the thermoplastic elastomer resin composition is 35A to 75A. [5] The molded product according to any one of items 1 to 4, wherein the elastic modulus at 10% elongation of the thermoplastic elastomer resin composition is 10 MPa or more. [6] The molded object according to any one of items 1 to 5, wherein the molded object has a surface layer and an infill layer, and the infill layer is exposed to the surface in one or more places. [7] The molded object according to any one of items 1 to 6, wherein the minimum value of the Shore A hardness of the molded object is 30A or less. [8] The molded object according to any one of items 1 to 7, wherein the Shore A hardness ratio, calculated by the following formula: (Shore A hardness ratio) = (minimum value of Shore A hardness in the molded object) / (maximum value of Shore A hardness in the molded object), is 65% or less. [9] A method for manufacturing the molded object according to any one of items 1 to 8, comprising molding a thermoplastic elastomer resin composition with a 3D printer.

[10] The method according to item 9, wherein the thermoplastic elastomer resin composition is supplied to the 3D printer as a filament-like 3D printing material, and the molten 3D printing material is extruded from the extrusion port of the 3D printer.

[11] The method according to item 10, wherein the filament is melted in the heating section of the 3D printer, the molten fluid is discharged from the discharge port of the heating section, the ratio F / N of the buckling load F of the filament to the pressure loss load N applied to the filament due to the pressure loss of the fluid in the heating section is 1 to 20, and the Young's modulus of the filament is 50 MPa or less.

[12] The method according to any one of items 9 to 11, wherein the thermoplastic elastomer resin composition is extruded from the nozzle of the 3D printer and additively manufactured, and the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D of the nozzle (Pmax / D) is 0.05 or more and less than 0.5.

[13] A thermoplastic elastomer resin composition for additive manufacturing, wherein the flexibility index of the thermoplastic elastomer resin composition is 65% or less, and the flexibility index is the value obtained by dividing the hardness of the upper center of the dome shape of a test molded object, which is made by molding the thermoplastic elastomer resin composition to have a dome-shaped outer wall with a width of 63 mm x depth of 82 mm x height of 15 mm, a gyroid shape with a filling rate of 10%, two bottom layers in the 45° and 135° directions, and eight solid layers arranged concentrically, by the hardness of the thermoplastic elastomer resin composition, and the hardness is measured by a hardness tester in accordance with ISO 7619.

[14] The thermoplastic elastomer resin composition according to item 13, wherein when the thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and additively manufactured, the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D of the nozzle (Pmax / D) is 0.05 or more and less than 0.5.

[0008] According to the present invention, it is possible to provide a molding material that offers an excellent balance between moldability and the flexibility of the molded object, and that allows for a large difference in hardness within the molded object.

[0009] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). It should be noted that the present invention is not limited to the following embodiments, and can be implemented in various modifications within the scope of its gist.

[0010] ≪Thermoplastic Elastomer Resin Composition≫ One aspect of the present invention provides a molded product which is an addendum of a thermoplastic elastomer resin composition. The thermoplastic elastomer resin composition comprises a thermoplastic elastomer. In one aspect, the minimum hardness of the molded product is 65% or less of the hardness of the thermoplastic elastomer resin composition. These hardnesses are measured using a hardness tester in accordance with ISO 7619, and more specifically, they are Shore A hardness. The hardness of the thermoplastic elastomer resin composition is measured using a test piece in accordance with ISO 37 type 3. More detailed measurement methods are described in the [Examples] section of this disclosure. In one aspect, the minimum hardness of the molded product is measured over an area of ​​10 mm² on the surface of the molded product. 2 This is the minimum value obtained when measuring Shore hardness for each individual.

[0011] In one embodiment, the ratio of the minimum hardness of the molded object to the hardness of the thermoplastic elastomer resin composition, with the hardness of the thermoplastic elastomer resin composition set to 100%, is 65% or less, preferably 60% or less, more preferably 55% or less, or 50% or less, or 45% or less, even more preferably 35% or less, or 30% or less, and particularly preferably 20% or less. The fact that the above ratio is within the above range indicates that the thermoplastic elastomer resin composition has excellent moldability, making it possible to form molded objects with extremely high flexibility. Molded objects obtained using such a thermoplastic elastomer resin composition can exhibit the unique property of being able to have an extremely large difference in hardness within the molded object. Furthermore, because the molded object of this embodiment has excellent moldability, it can be molded even with a low filler ratio of the thermoplastic elastomer resin composition, and in one embodiment, it can be extremely lightweight. While a lower ratio is advantageous, from the viewpoint of the mechanical strength of the molded object, in one embodiment, it may be 0.1% or more, or 1% or more, or 3% or more, or 5% or more.

[0012] The above ratio can be adjusted by appropriately setting the balance between the hardness and elastic modulus of the thermoplastic elastomer resin composition, and by appropriately setting the type and amount of additives such as cellulose fibers.

[0013] In one embodiment of the thermoplastic elastomer resin composition, the flexibility index determined by the following method is 65% or less. (Method for determining the flexibility index) The flexibility index is the value obtained by dividing the hardness of the upper center of the dome shape of a test molded object, which is made by molding the thermoplastic elastomer resin composition to have a dome-shaped outer wall with a width of 63 mm x depth of 82 mm x height of 15 mm, a gyroid-shaped infill with a filling rate of 10%, two bottom layers in the 45° direction and 135° direction, and eight solid layers arranged concentrically, by the hardness of the thermoplastic elastomer resin composition. The hardness is a value measured by a hardness tester in accordance with ISO 7619, and more specifically, it is the Shore A hardness. The hardness of the thermoplastic elastomer resin composition is measured with a test specimen in accordance with ISO 37 type 3. A more detailed measurement method is described in the [Examples] section of this disclosure.

[0014] The molded object of this embodiment is not limited to the shape of the test molded object described above and may have various shapes. However, the fact that the test molded object exhibits a flexibility index within the above range indicates that the molded object of this embodiment may exhibit the unique properties of this disclosure.

[0015] The shape of the printed object can be designed by loading the desired model shape into the additive manufacturing equipment (more specifically, the 3D printer) and directly inputting various parameters. The shape of the test object can be set in the 3D printer as follows: The dome shape is specifically a rectangular shape with rounded corners (i.e., R-shaped) on each side of 20 mm, and in side view, the bottom surface is horizontal, with both side walls having a curved shape with a radius of R15 mm. The gyroid shape and its infill density are set according to the 3D printer's slicer. The number of bottom layers is set to two, with angles of 45° and 135°. The solid layers are set concentrically according to the 3D printer's slicer.

[0016] The flexibility index is preferably 60% or less, more preferably 55% or less, or 50% or less, or 45% or less, or 40% or less, even more preferably 35% or less, or 30% or less, and particularly preferably 20% or less. The fact that the flexibility index of the thermoplastic elastomer resin composition constituting the molded object is within this range indicates that the thermoplastic elastomer resin composition has excellent moldability, enabling the formation of molded objects with extremely high flexibility. Molded objects obtained using such a thermoplastic elastomer resin composition may exhibit the unique property of having extremely large differences in hardness within the molded object. Furthermore, because the molded object of this embodiment has excellent moldability, it can be molded even with a low filler density of the thermoplastic elastomer resin composition, and in one embodiment, it can be extremely lightweight. While a lower flexibility index is advantageous, from the viewpoint of the mechanical strength of the molded object, in one embodiment, it may be 0.1% or more, or 1% or more, or 3% or more, or 5% or more.

[0017] The flexibility index mentioned above can be adjusted by appropriately setting the balance between the Shore A hardness and elastic modulus of the thermoplastic elastomer resin composition, and by appropriately setting the type and amount of additives such as cellulose fibers.

[0018] (Forming pitch coefficient of thermoplastic elastomer resin composition) In one embodiment, when a thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and additively manufactured, the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D (Pmax / D), that is, the forming pitch coefficient calculated by the following formula, is preferably less than 0.50 and 0.05 or more. (Forming pitch coefficient (Pmax / D)) = (Maximum layer pitch that can be manufactured by a 3D printer (Pmax)) / (Nozzle diameter (D)) In one embodiment, in the method for manufacturing a molded object, a thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and additively manufactured, and the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D (Pmax / D) is preferably 0.05 or more and less than 0.5. The above forming pitch coefficient is more preferably 0.10 to 0.40, and even more preferably 0.15 to 0.38. When the above molding pitch coefficient is within the above range, the molding process is less prone to distortion when creating objects with a low infill density or objects with a large height dimension. Furthermore, because there is an excellent balance between the adhesion between layers and the rigidity of the internal structure of the object, it is possible to create remarkably flexible objects.

[0019] With respect to the build pitch, "buildable" means that the actual dimensions of the buildable object (specifically, the width and thickness dimensions of the strip-shaped test piece) are within ±10% of the 3D printer's set dimensions. The set dimensions are those set by loading the desired model shape into the 3D printer, directly inputting each parameter, etc. In this disclosure, the maximum buildable buildable layer pitch Pmax means the maximum value among the 3D printer's set layer pitch values ​​that was "buildable" as described above. If layers are built with a layer pitch exceeding the maximum buildable buildable layer pitch Pmax, insufficient pressure may be applied to the layered surface during build, or the layered layers may not have sufficient bonding area, which can lead to build defects or layering failures. The build pitch coefficient can be adjusted by setting the viscosity and elastic modulus (in one embodiment, the elastic modulus at 10% elongation) of the thermoplastic elastomer resin composition to an appropriate range. Methods for increasing the molding pitch coefficient include adjusting the viscosity and modulus of the thermoplastic elastomer resin composition so that good adhesion is possible even with low pressure and contact area, and in one embodiment, setting the ratio of the modulus to the viscosity to a specific range. Specific examples include setting the product of the viscosity of the thermoplastic elastomer resin composition (specifically, the melt flow rate measured at a temperature of 280°C and a load of 2.16 kg, g / 10 min) and the modulus of elasticity (stress at a tensile strain of 15%, MPa) to 50 or more. Lower viscosity tends to result in better lamination adhesion as the thermoplastic elastomer resin composition is extruded from the nozzle, and the thermoplastic elastomer resin composition is extruded more stably, resulting in better lamination adhesion. Higher modulus tends to result in better lamination adhesion as the thermoplastic elastomer resin composition is extruded more stably. The viscosity and modulus of the thermoplastic elastomer resin composition can be controlled by adjusting the properties of the thermoplastic elastomer (viscosity, modulus of elasticity), the type and / or amount of additives such as cellulose fibers, etc. The molding pitch coefficient can be determined by the method described in the [Examples] section of this disclosure. It is preferable to thoroughly dry the thermoplastic elastomer resin composition before molding.

[0020] The molding pitch coefficient when a thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and additively manufactured (i.e., as a property of the thermoplastic elastomer resin composition itself) is a value obtained when the ambient temperature is room temperature (specifically 23°C), the nozzle diameter is 0.8 mm, the nozzle temperature is 300°C, and the bed temperature is 60°C. On the other hand, the molding pitch coefficient related to the manufacturing method of the molded object is a value obtained under the process conditions used in that method. In one embodiment, the molding pitch coefficient related to the manufacturing method of the molded object is a value obtained when the ambient temperature is room temperature (specifically 23°C), the nozzle diameter is 0.8 mm, the nozzle temperature is 300°C if the elastomer is styrene-based elastomer, 240°C if the elastomer is urethane-based elastomer, 230°C if the elastomer is ester-based elastomer, and 280°C if the elastomer is other elastomers, and the bed temperature is 60°C if the elastomer is styrene-based elastomer and 23°C if the elastomer is other elastomers.

[0021] The thermoplastic elastomer resin composition of this embodiment preferably contains cellulose fibers. Such a thermoplastic elastomer resin composition is preferable from the viewpoint of mold stability, adhesion to the build plate, reduction of shrinkage rate of the molded object, and reduction of warping of the molded object.

[0022] (10% average fiber length of cellulose fibers contained in thermoplastic elastomer resin composition) In one embodiment, the 10% average fiber length of cellulose fibers contained in the thermoplastic elastomer resin composition is preferably 20 μm or more, 30 μm or more, or 40 μm or more, and preferably 100 μm or less, 80 μm or less, or 70 μm or less. Having the above range for the 10% average fiber length of cellulose fibers is preferable from the viewpoint of adhesion to the build plate during molding, suppression of shrinkage of the molded object, and suppression of warping of the molded object.

[0023] The 10% average fiber length of cellulose fibers contained in the thermoplastic elastomer resin composition can be adjusted, for example, by setting the cellulose fiber length of the raw materials for the thermoplastic elastomer resin composition to an appropriate range, and by appropriately setting the temperature, residence time, and amount of thermoplastic elastomer (preferably the amount of acid-modified elastomer) during the production of the thermoplastic elastomer resin composition.

[0024] In one embodiment, the 10% average fiber length of the cellulose fibers in this disclosure is a value measured using a microscope by the following procedure: The thermoplastic elastomer of the thermoplastic elastomer resin composition is dissolved in a solvent (for example, toluene if the thermoplastic elastomer is a styrene-based elastomer), the obtained solution is dropped onto a slide, a glass cover is placed over it and sandwiched, and observed with a microscope. The obtained image is processed using ImageJ according to the following procedure, and the average value of the fiber lengths of the fibers that fall in the top 10% of the obtained fibers is taken as the 10% average fiber length of the cellulose fibers contained in the thermoplastic elastomer resin composition. The fiber length measured by this measurement method is a value measured for fibers with a fiber diameter of 1 μm or more. However, according to the inventors' studies, fibers with a fiber diameter of less than 1 μm can be considered to have substantially the same fiber length as fibers with a fiber diameter of 1 μm or more. Therefore, in this disclosure, the value obtained by the above procedure is treated as the 10% average fiber length of the cellulose fibers.

[0025] (Processing with ImageJ) In one embodiment, processing with ImageJ can be performed as follows: 1. After loading the image, convert it to 8-bit (Image > Type > 8bit) 2. Filtering (Plugins > Bilateral Filter > Bilateral Fiji; spatial radius: 1, range radius: 10) 3. Background removal (Process > Subtract Background; Rolling ball radius: 10 pixels) 4. Binarization (Image > Adjust > Threhold (Triangle)) 5. 1. Noise Reduction (Analyze > Analyze particles; Size: 15-Infinity, Circularity: 0.00-0.40) 6. Thinning (Process > Binary > Skeltonize) 7. Fiber Length Evaluation (Plugins > RidgeDetection; Line width: 25, High Contrast: 230, Low Contrast: 87, Sigma: 7.72, Lower Trehold: 0.00, Upper Trehold: 0.17, Minimum Line Length: 20, Maximum Line Length: 0.00)

[0026] In one embodiment, the fiber diameter of the cellulose fiber may be 2 to 5000 nm from the viewpoint of obtaining a good effect of improving physical properties. The number-average fiber diameter of the cellulose fiber is more preferably 4 nm or more, or 5 nm or more, or 10 nm or more, or 15 nm or more, or 20 nm or more, and more preferably 3000 nm or less, or 1000 nm or less, or 900 nm or less, or 800 nm or less, or 700 nm or less, or 600 nm or less, or 500 nm or less, or 400 nm or less, or 300 nm or less, or 200 nm or less.

[0027] In one embodiment, the cellulose fibers may include fibers of different diameters, and it is preferable to include cellulose fibers having a fiber diameter of less than 500 nm, or 400 nm or less, or 300 nm or less, or 200 nm or less, preferably 100 nm or less, or 50 nm or less, and cellulose fibers with a diameter of 2000 nm to 5000 nm, in terms of reducing the warping of the molded object, improving the strength of the molded object, reducing voids in the molded object, and improving the adhesion between pass lines of the molded object.

[0028] The fiber diameter of the cellulose fibers contained in the thermoplastic elastomer resin composition can be adjusted, for example, by appropriately setting the beating and micronization processes during the preparation of the cellulose fiber raw material.

[0029] The number-average fiber length (L) / number-average fiber diameter (D) ratio of cellulose fibers is preferably 30 or more, or 50 or more, or 80 or more, or 100 or more, or 120 or more, or 150 or more, from the viewpoint of effectively improving the mechanical properties of the thermoplastic elastomer resin composition with a small amount of cellulose fibers. The upper limit is not particularly limited, but from the viewpoint of ease of handling, it is preferably 5000 or less, or 3000 or less, or 2000 or less, or 1000 or less.

[0030] In one embodiment, the number-average fiber diameter (D), number-average fiber length (L), and L / D ratio of the cellulose fibers of this disclosure are values ​​measured using a scanning electron microscope (SEM) by the following procedure. A thermoplastic elastomer is dissolved in a solvent (for example, toluene if the thermoplastic elastomer is a styrene-based elastomer), cast onto an osmium-deposited silicon substrate, and air-dried to form a measurement sample, which is then measured using a high-resolution scanning electron microscope (SEM). Specifically, the length (L) and diameter (D) of 100 randomly selected fibrous materials are measured in an observation field adjusted to the magnification so that at least 100 fibrous materials can be observed, and the ratio (L / D) is calculated. For the cellulose fibers, the number-average values ​​of length (L), diameter (D), and ratio (L / D) are calculated.

[0031] The Young's modulus of the thermoplastic elastomer resin composition may, in one embodiment, be 50 MPa or less, 40 MPa or less, or 30 MPa or less, and in another embodiment, it may be 10 MPa or more, 20 MPa or more, or 25 MPa or more. The Young's modulus is a value measured in accordance with ISO 527-1. The Young's modulus of the thermoplastic elastomer resin composition can be adjusted, for example, by adjusting the Young's modulus of the thermoplastic elastomer, or by appropriately setting the type and amount of additives, including cellulose fibers. In one embodiment, the Young's modulus of the thermoplastic polymer may be within the above range.

[0032] (Hardness of Thermoplastic Elastomer Resin Composition) In one embodiment, the hardness of the thermoplastic elastomer resin composition is preferably 90A or less, or 85A or less, more preferably 80A or less, or 75A or less, and even more preferably 70A or less, from the viewpoint of good flexibility and tensile elongation of the molded product, in terms of Shore A hardness. Furthermore, from the viewpoint of moldability, it is preferable to have a hardness of 5A or more, or 10A or more, or 20A or more, or 30A or more, or 35A or more, or 40A or more, or 50A or more, or 55A or more. The hardness of the thermoplastic elastomer resin composition is a value measured by a hardness tester in accordance with ISO 7619. The hardness of the thermoplastic elastomer resin composition can be adjusted, for example, by adjusting the hardness of the thermoplastic elastomer, or by appropriately setting the type and amount of additives, including cellulose fibers. In one embodiment, the Shore A hardness of the thermoplastic polymer may be within the above range.

[0033] (Modular modulus of thermoplastic elastomer resin composition at 10% elongation) In one embodiment, the modulus of thermoplastic elastomer resin composition at 10% elongation is preferably 10 MPa or more, 20 MPa or more, or 30 MPa or more, from the viewpoint of mold stability and reduction of shrinkage during molding. Also, from the viewpoint of flexibility of the molded product, it is 1000 MPa or less, 500 MPa or less, 300 MPa or less, 200 MPa or less, 100 MPa or less, or 50 MPa or less. The modulus of thermoplastic elastomer resin composition at 10% elongation can be determined by injection molding the thermoplastic elastomer resin composition into a dumbbell-shaped test piece conforming to JIS K6251 No. 3 dumbbell, performing a tensile test, and multiplying the stress at 10% elongation by 10. The 10% elongation modulus of a thermoplastic elastomer resin composition can be adjusted, for example, by adjusting the 10% elongation modulus of the thermoplastic elastomer, or by appropriately setting the type and amount of additives, including cellulose fibers.

[0034] (Viscosity of thermoplastic elastomer resin composition and thermoplastic elastomer) The viscosity (melt flow rate) of the thermoplastic elastomer resin composition or thermoplastic elastomer is preferably within a predetermined range in terms of balancing moldability and flexibility of the molded product. In one embodiment, the viscosity of the thermoplastic elastomer resin composition and the thermoplastic elastomer at 280°C is preferably 10 g / 10 min or more, or 15 g / 10 min or more, or 20 g / 10 min or more in terms of good interlayer adhesion in additive manufacturing, and preferably 200 g / 10 min or less, or 150 g / min or less, or 100 g / 10 min or less, or 70 g / 10 min or less in terms of preventing the generation of whiskers in the molded product due to resin dripping from the nozzle and a decrease in dimensional accuracy.

[0035] The viscosity (melt flow rate) of the thermoplastic elastomer resin composition and the thermoplastic elastomer is measured using a semi-automatic melt indexer with a load of 2.16 kg and an orifice diameter of 2.5 mmΦ.

[0036] (Water absorption rate of thermoplastic elastomer resin composition) In one embodiment, the water absorption rate of the thermoplastic elastomer resin composition is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, or 0.3% by mass or less, and even more preferably 0.2% by mass or less, from the standpoint of achieving good surface roughness of the molded product (more specifically, achieving a desired surface roughness), improving the physical properties of the molded product, and improving the dimensional accuracy of the molded product. The water absorption rate of the thermoplastic elastomer resin composition is a value measured using a Karl Fischer moisture meter in accordance with ISO 15512. The water absorption rate of the thermoplastic elastomer resin composition can be adjusted, for example, by drying it under appropriate conditions in a vacuum dryer or a hot air circulation dryer, or by sealing and storing it in an aluminum bag immediately after the polymer composition is manufactured.

[0037] The water absorption rate of thermoplastic elastomer resin compositions is measured using a Karl Fischer moisture meter in accordance with ISO 15512.

[0038] The water absorption rate of the thermoplastic elastomer resin composition can be adjusted, for example, by drying it under appropriate conditions in a vacuum dryer or a hot air circulation dryer, or by sealing and storing it in an aluminum bag immediately after manufacturing.

[0039] (Porosity of Thermoplastic Elastomer Resin Composition) In one embodiment, the porosity of the thermoplastic elastomer resin composition is preferably 2% or less, and more preferably 1% or less, or 0.5% or less, or 0.2% or less, or 0.1% or less, from the viewpoint of improving the dimensional accuracy of the molded object, reducing ejection defects during molding, reducing the voids in the molded object, and improving the physical properties of the molded object.

[0040] The porosity of a thermoplastic elastomer resin composition can be measured by cutting the composition with a microtome, observing the cross-section with a scanning electron microscope (SEM), and performing image analysis. The porosity of a thermoplastic elastomer resin composition can be adjusted, for example, by appropriately setting the fiber length and diameter of the cellulose fibers contained in the composition, and the temperature conditions during the manufacturing of the thermoplastic elastomer resin composition. The porosity can be measured by cutting the composition with a microtome, observing the cross-section with a scanning electron microscope (SEM), and performing image analysis. The porosity of a thermoplastic elastomer resin composition can be adjusted, for example, by appropriately setting the fiber length and diameter of the cellulose fibers contained in the composition, and the temperature conditions during the manufacturing of the polymer composition.

[0041] (Agglutins contained in thermoplastic elastomer resin composition) In one embodiment, the amount of aggregates with a major axis (i.e., maximum cross-section diameter) of 0.3 mm or more contained in the thermoplastic elastomer resin composition is preferably 2 particles / g or less, more preferably 1 particle / g or less, or 0.5 particles / g or less, and even more preferably 0.1 particles / g or less, from the viewpoint of nozzle clogging during molding and the appearance of the molded product. The amount of aggregates is a value measured by the method described in the [Examples] section of this disclosure. The amount of aggregates can be adjusted, for example, by appropriately setting the amount and type of dispersant contained in the thermoplastic elastomer resin composition, the fiber length and fiber diameter of the cellulose fibers, and the temperature conditions during the production of the thermoplastic elastomer resin composition.

[0042] The amount of aggregates in a thermoplastic elastomer resin composition can be adjusted, for example, by appropriately setting the amount and type of dispersant contained in the thermoplastic elastomer resin composition, the fiber length and fiber diameter of the cellulose fibers, and the temperature conditions during the production of the thermoplastic elastomer resin composition. In this disclosure, "additive manufacturing" means a process of constructing a three-dimensional object by progressively adding (laminating) material, in contrast to removal manufacturing represented by cutting. Generally, materials for additive manufacturing can have a versatile form that can form various three-dimensional objects by melting or other means. In one embodiment, the thermoplastic elastomer resin composition may have at least one form selected from pellets, powders, filaments, plates, or molten products thereof. These forms may be suitable for additive manufacturing. Examples of 3D printing methods as additive manufacturing include material extrusion deposition (MEX) (e.g., pellet melt deposition, fused deposition), stereolithography, material jetting, powder bonding, powder bed fusion, etc. The thermoplastic elastomer resin composition of this embodiment is, in one embodiment, a thermoplastic elastomer resin composition for 3D printing, and in another embodiment, a thermoplastic elastomer resin composition for material extrusion lamination (MEX). Below, the thermoplastic elastomer resin composition of this embodiment will be described in more detail, with appropriate reference to the exemplary embodiments in the case of material extrusion lamination (MEX).

[0043] <Thermoplastic Elastomer> In this disclosure, thermoplastic elastomer means a thermoplastic substance (specifically, a natural or synthetic polymer) that is elastic at room temperature (23°C). In one embodiment, being elastic means that the storage modulus of elasticity measured by dynamic viscoelasticity measurement at 23°C and 10 Hz is 1 MPa or more and 100 MPa or less.

[0044] The number-average molecular weight (Mn) of the thermoplastic elastomer is preferably 10,000 to 500,000 or 40,000 to 250,000, from the viewpoint of achieving both impact strength and fluidity.

[0045] In one embodiment, examples of thermoplastic elastomers include styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, ester-based elastomers, polyamide-based elastomers, and vinyl chloride-based elastomers. From the viewpoint of easy adjustment of the flexibility of the molded product and moldability in additive manufacturing, styrene-based elastomers are preferred. The thermoplastic elastomer may also be a crosslinked product.

[0046] In one embodiment, the styrene-based elastomer is a copolymer of a conjugated diene monomer and an aromatic vinyl monomer. Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, which may be used individually or in combination of two or more. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with the conjugated diene monomer, and examples include styrene, m or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene, which may be used individually or in combination of two or more. From the viewpoint of moldability of the thermoplastic elastomer resin composition and impact resistance of the molded product, styrene is preferred.

[0047] Examples of random copolymers include butadiene-styrene random copolymers, isoprene-styrene random copolymers, and butadiene-isoprene-styrene random copolymers. Regarding the compositional distribution of each monomer in the copolymer chain, examples include perfectly random copolymers with a composition close to statistically random, and tapered random copolymers with a gradient in the compositional distribution. The bonding mode of the conjugated diene polymer, i.e., the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or different between molecules.

[0048] A block copolymer may be a copolymer consisting of two or more blocks. For example, a block copolymer may have a structure such as A-B, A-B-A, A-B-A-B, etc., where block A is an aromatic vinyl monomer and block B is a block of conjugated diene monomer and / or a copolymer of aromatic vinyl monomer and conjugated diene monomer. The boundaries of each block do not necessarily need to be clearly distinguishable; for example, if block B is a copolymer of aromatic vinyl monomer and conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or in a tapered manner. Furthermore, block B may have multiple portions where the aromatic vinyl monomer is uniformly distributed and / or distributed in a tapered manner. In addition, block B may have multiple segments with different aromatic vinyl monomer content. When multiple blocks A and block B exist in the copolymer, their molecular weights and compositions may be the same or different.

[0049] The styrene-based elastomer may be an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated version thereof. The block copolymer may be a mixture of two or more types in which one or more of the following are different: bond type, molecular weight, aromatic vinyl compound species, conjugated diene compound species, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc.

[0050] The styrene-based elastomer may be partially hydrogenated or fully hydrogenated. From the viewpoint of suppressing thermal degradation during processing, the hydrogenation rate of the hydrogenated material is preferably 50% or more, 80% or more, or 98% or more, and from the viewpoint of low-temperature toughness, it is preferably 50% or less, 20% or less, or 0% (i.e., unhydrogenated). Examples of hydrogenated conjugated diene polymers include the hydrogenated conjugated diene polymers exemplified above, and may be, for example, hydrogenated styrene-butadiene copolymers.

[0051] In one embodiment, the styrene elastomer may be unmodified, modified, for example, acid-modified, or a mixture thereof.

[0052] Acid-modified styrene elastomers may be acid-modified products of the styrene elastomers exemplified above. In this disclosure, an acid-modified styrene elastomer means that an acidic functional group is added to the molecular skeleton of a styrene elastomer via a chemical bond as an acid-modifying group. In this disclosure, an acidic functional group means a functional group that can react with basic functional groups, etc. Specific examples include hydroxyl groups, carboxyl groups, carboxylate groups, sulfo groups, acid anhydride groups, etc.

[0053] The acid modification rate, which is the mass ratio of acid-modified groups in 100% by mass of acid-modified styrene-based elastomer, is preferably 0.2% by mass or more, or 0.3% by mass or more, or 0.5% by mass or more, or 1% by mass or more, or 1.5% by mass or more, based on 100% by mass of acid-modified styrene-based elastomer, from the viewpoint of void reduction effect due to good affinity with cellulose fibers. From the viewpoint of affinity with components other than acid-modified styrene-based elastomer when the thermoplastic elastomer contains such components, it is preferably 2.5% by mass or less, or 2.3% by mass or less, or 2% by mass or less. The acid modification rate is obtained by measuring a calibration curve prepared by measuring a calibration curve sample that has been pre-mixed with an acidic substance using an infrared absorption spectrum analyzer, and then measuring the sample based on the calibration curve prepared using the characteristic absorption band of the acid.

[0054] In one preferred embodiment, the acid-modified styrene elastomer is an acid-modified styrene elastomer that is an aromatic vinyl compound-conjugated diene compound copolymer (preferably an aromatic vinyl compound-conjugated diene compound block copolymer) or a hydrogenated thereof. Examples of such acid-modified styrene elastomers include elastomers that are modified products obtained by grafting an α,β-unsaturated dicarboxylic acid or its derivative onto an aromatic compound-conjugated diene copolymer (preferably a block copolymer) or its hydrogenated thereof in the presence or absence of a peroxide. Specific examples of α,β-unsaturated dicarboxylic acids and their derivatives include maleic acid, fumaric acid, maleic anhydride, and fumaric anhydride, with maleic anhydride being particularly preferred among these. In a preferred embodiment, the acid-modified styrene elastomer is a styrene elastomer modified with an acid anhydride.

[0055] From the viewpoint of flexibility, moldability, and compatibility with acid-modified styrene-based elastomers, the styrene-based elastomer is preferably at least one selected from the group consisting of styrene-ethylene-butadiene-styrene block copolymer, styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-butadiene-butylene block copolymer, hydrogenated styrene-isoprene block copolymer, and styrene homopolymer (polystyrene). More preferably, the styrene-based elastomer is at least one selected from the group consisting of styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, and polystyrene. From the viewpoint of compatibility with the styrene elastomer, the acid-modified styrene elastomer is more preferably one or more of the acid-modified products exemplified above.

[0056] The styrene unit ratio of a styrene-based elastomer (e.g., acid-modified styrene-based elastomer) is preferably 10% by mass or more, or 19% by mass or more, or 29% by mass or more, from the viewpoint of exhibiting the advantageous properties inherent in the styrene-based elastomer and from the viewpoint of mutual affinity when two or more types of styrene-based elastomers are present, and preferably 45% by mass or less, or 40% by mass or less, or 35% by mass or less, from the viewpoint of hardness. The styrene unit ratio is a value that can be determined by the following method. Specifically, a predetermined amount of elastomer is dissolved in chloroform and measured using an ultraviolet spectrophotometer (e.g., Shimadzu Corporation, UV-2450), and the content of aromatic vinyl monomer units (styrene) is calculated using a calibration curve from the peak intensity of the absorption wavelength (262 nm) caused by the aromatic vinyl compound component (styrene).

[0057] When an acid-modified styrene elastomer is used in combination with a styrene elastomer other than the acid-modified styrene elastomer, the ratio of the styrene unit ratio of the styrene elastomer to the styrene unit ratio of the acid-modified styrene elastomer (styrene ratio of styrene elastomer / styrene ratio of acid-modified styrene elastomer) is preferably 0.3 or higher, 0.6 or higher, or 0.9 or higher, from the viewpoint of affinity between the acid-modified styrene elastomer and the styrene elastomer other than the acid-modified styrene elastomer, and preferably 2.5 or lower, 2 or lower, or 1.5 or lower, from the same viewpoint.

[0058] When an acid-modified styrene elastomer is used in combination with a styrene elastomer other than the acid-modified styrene elastomer, the ratio of the styrene unit ratio to the acid modification rate (styrene unit ratio / acid modification rate) of the acid-modified styrene elastomer is preferably 5 or more, or 10 or more, or 20 or more, from the viewpoint of affinity with the styrene elastomer other than the acid-modified styrene elastomer, and preferably 90 or less, or 85 or less, or 80 or less, from the viewpoint of affinity with cellulose fibers.

[0059] With respect to styrene-based elastomers (e.g., acid-modified styrene-based elastomers), the amount of vinyl bonds in the conjugated diene bond units in the conjugated diene polymer (e.g., 1,2- or 3,4- bonds of butadiene) is preferably 5 mol% or more, or 10 mol% or more, or 13 mol% or more, or 15 mol% or more, and preferably 80 mol% or less, or 75 mol% or less, or 65 mol% or less, or 50 mol% or less, or 40 mol% or less. The amount of vinyl bonds in the conjugated diene bond units (e.g., the amount of 1,2- bonds of butadiene) is 13 It can be determined by the 13C-NMR method (quantitative mode). That is, 13 In 1C-NMR, integrating the peak areas shown below yields values ​​proportional to the carbon content of each structural unit, which can then be converted to mass percentages of each structural unit. Styrene: 145–147 ppm; Vinyl: 110–116 ppm; Diene (cis): 24–28 ppm; Diene (trans): 29–33 ppm

[0060] In a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of aromatic vinyl monomer bonded to the conjugated diene monomer (hereinafter also referred to as the aromatic vinyl bond amount) may preferably be 5.0% by mass or more and 70% by mass or 10% by mass or more and 50% by mass or less, based on the total mass of the styrene-based elastomer. The aromatic vinyl bond amount can be determined by the ultraviolet absorbance of the phenyl group, and the conjugated diene bond amount can also be determined based on this.

[0061] The number average molecular weight (Mn) of the acid-modified styrene elastomer is preferably 10,000 or more, 30,000 or more, or 50,000 or more, from the viewpoint of elongation of the molded product and affinity with components other than the acid-modified styrene elastomer when the thermoplastic elastomer contains such components, and preferably 500,000 or less, 250,000 or less, or 200,000 or less, from the viewpoint of affinity with cellulose fibers.

[0062] The number-average molecular weight (Mn) of the styrene-based elastomer is preferably 10,000 to 500,000 or 40,000 to 250,000, from the viewpoint of achieving both impact strength and fluidity.

[0063] In one embodiment, the amount of thermoplastic elastomer in 100% by mass of the thermoplastic elastomer resin composition is 60% by mass or more, 65% by mass or more, 70% by mass or more, or 75% by mass or more. Such a resin composition can exhibit good flexibility, moldability, rubber elasticity, weather resistance, chemical resistance, etc. From the viewpoint of including a desired amount of other components, particularly cellulose fibers, the above amount is 90% by mass or less, 85% by mass or less, or 80% by mass or less in one embodiment.

[0064] When acid-modified styrene elastomers and styrene elastomers other than acid-modified styrene elastomers are used in combination, the amount of acid-modified styrene elastomer per 100 parts by mass of styrene elastomers other than acid-modified styrene elastomers is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 3 parts by mass or more, from the viewpoint of pass line adhesion of the molded product, warping suppression, extrusion stability during molding with filaments, and resistance to whitening during tensile stress of the molded product (void generation suppression). From the viewpoint of suppressing discoloration caused by a large amount of acid-modified styrene elastomers, pass line adhesion of the molded product, warping suppression of the molded product, extrusion stability during molding with filaments, shrinkage suppression during molding, and / or reduction in hardness of the molded product, it is preferably 50 parts by mass or less, or 40 parts by mass or less, or 30 parts by mass or less, or 20% by mass or less, more preferably 15 parts by mass or less, or 10 parts by mass or less.

[0065] The amount of acid-modified styrene elastomer per 1 part by mass of cellulose fiber is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 5 parts by mass or more, from the viewpoint of improving the surface smoothness of the molded product and the resistance to whitening during tension of the molded product (suppression of void generation). From the viewpoint of suppressing discoloration caused by a large amount of acid-modified styrene elastomer, improving the adhesion of the pass line of the molded product, suppressing warping of the molded product, improving the extrusion stability when using filament molding, suppressing shrinkage during molding, and / or suppressing the reduction in hardness of the molded product, it is preferably 45 parts by mass or less, or 40 parts by mass or less, or 35 parts by mass or less, or 30 parts by mass or less, or 20% by mass or less, more preferably 15 parts by mass or less, or 10 parts by mass or less.

[0066] In one embodiment of the thermoplastic elastomer resin composition, the number of acid-modified styrene-based elastomers can be kept below the number of hydroxyl groups on the surface of the cellulose fibers (specifically, the part that gives surface area in the specific surface area measurement of the cellulose fibers). The number of hydroxyl groups on the surface of the cellulose fibers in the resin composition can be calculated from the amount of cellulose fibers in the resin composition, the fiber diameter, and the specific surface area. For example, when using an acid-modified substance for the purpose of chemically modifying cellulose fibers, an excess amount of the acid-modified substance may be added to the cellulose fibers. However, in this embodiment, it may be advantageous to keep the amount of acid-modified styrene-based elastomer present in the resin composition to the minimum necessary while maintaining the desired affinity with the cellulose fibers. From this viewpoint, it is preferable that the amount of acid-modified styrene-based elastomer be adjusted so as not to be excessive relative to the number of hydroxyl groups of the cellulose fibers, and the upper limit of the above example is preferable from this viewpoint.

[0067] The amount of acid-modified groups in the acid-modified styrene elastomer relative to 100% by mass of cellulose fibers is preferably 0.2% by mass or more, or 0.5% by mass or more, or 0.8% by mass or more, or 1.0% by mass or more, or 1.2% by mass or more, or 1.5% by mass or more, based on 100% by mass of the acid-modified styrene elastomer, from the viewpoint of affinity with cellulose fibers, and preferably 5.0% by mass or less, or 3.0% by mass or less, or 2.5% by mass or less, or 2.0% by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or decrease in hardness caused by the acid-modified styrene elastomer.

[0068] The amount of acid-modified styrene-based elastomer in 100% by mass of the thermoplastic elastomer resin composition is preferably 0.5% by mass or more, or 1% by mass or more, or 5% by mass or more, from the viewpoint of improving the surface smoothness of the molded product and the resistance to whitening during tensile stress (suppression of void formation) of the molded product. From the viewpoint of suppressing discoloration, shrinkage during molding, and / or reduction in hardness caused by a large amount of acid-modified styrene-based elastomer, it is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less. Note that acid-modified styrene-based elastomers are generally relatively expensive, so reducing the amount used is advantageous from a cost perspective.

[0069] In one embodiment, the behavior of the stress-strain curve (e.g., yield behavior) in a tensile test of a thermoplastic elastomer resin composition may be controlled according to the desired application of the resin composition by selecting the type and / or amount of acid-modified styrene elastomer.

[0070] The amount of styrene-based elastomer per 1 part by mass of cellulose fiber is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 5 parts by mass or more, from the viewpoint of obtaining the good rubber elasticity, weather resistance and chemical resistance inherent in styrene-based elastomer, and preferably 250 parts by mass or less, or 200 parts by mass or less, or 150 parts by mass or less, from the viewpoint of improving the surface smoothness and hardness of the molded product.

[0071] The amount of styrene-based elastomer in 100% by mass of the thermoplastic elastomer resin composition is preferably 10% by mass or more, 20% by mass or more, or 30% by mass or more, from the viewpoint of allowing the advantageous properties inherent in the styrene-based elastomer to be exhibited well, and preferably 98.8% by mass or less, 90% by mass or less, or 80% by mass or less, from the viewpoint of including other components in desired amounts.

[0072] The melt mass flow rate (MFR) of the styrene-based elastomer at 230°C and 2.16 kg is preferably 20 g / 10 min or less, or 15 g / 10 min or less, or 10 g / 10 min or less, from the viewpoint of obtaining good mechanical properties of the thermoplastic elastomer resin composition, and preferably 0.1 g / 10 min or more, or 0.5 g / 10 min or more, or 1.0 g / 10 min or more, from the viewpoint of facilitating melt processing.

[0073] <Cellulose Fibers> The thermoplastic elastomer resin composition of this embodiment preferably contains cellulose fibers from the viewpoint of moldability, suppression of shrinkage of molded objects, suppression of warping, and interlayer adhesion.

[0074] Cellulose fibers may be obtained from various cellulose fiber raw materials selected from natural cellulose and regenerated cellulose. As natural cellulose, wood pulp obtained from wood species (hardwood or softwood), non-wood pulp obtained from non-wood species (cotton, bamboo, hemp, bagasse, kenaf, cotton linter, sisal, straw, etc.), and cellulose fiber aggregates produced by animals (e.g., sea squirts), algae, or microorganisms (e.g., acetic acid bacteria) can be used. As regenerated cellulose, regenerated cellulose fibers (viscose, cupro, Tencel, etc.), cellulose derivative fibers, and ultrafine threads of regenerated cellulose or cellulose derivatives obtained by electrospinning can be used. Cellulose fibers from linter pulp are preferred from the viewpoint of having higher heat resistance compared to those using other cellulose raw materials. These raw materials can be processed as needed by mechanical methods such as beating, fibrillation, and micronization using grinders, refiners, etc., to adjust the fiber diameter, fiber length, degree of fibrillation, etc., or by bleaching and purifying them with chemicals to adjust the content of components other than cellulose (such as acid-insoluble components like lignin, alkali-soluble polysaccharides like hemicellulose, etc.). As a specific method for obtaining cellulose fibers from cellulose raw materials, for example, a method described in Japanese Patent Application Publication No. 2024-031890 may be used.

[0075] [Number-average fiber length, number-average fiber diameter, and L / D of cellulose fiber raw material] In one embodiment, the number-average fiber length of the cellulose fiber raw material is preferably 10 μm or more, or 20 μm or more, or 40 μm or more, or 50 μm or more, or 70 μm or more, and more preferably 90 μm or more, or 100 μm or more, or 110 μm or more. In one embodiment, the number-average fiber diameter of the cellulose fiber raw material is preferably 2 to 5000 nm from the viewpoint of obtaining a good effect of improving physical properties by cellulose fibers. The number-average fiber diameter of the cellulose fiber raw material is more preferably 4 nm or more, or 5 nm or more, or 10 nm or more, or 15 nm or more, or 20 nm or more, and more preferably 3000 nm or less, or 1000 nm or less, or 900 nm or less, or 800 nm or less, or 700 nm or less, or 600 nm or less, or 500 nm or less, or 400 nm or less, or 300 nm or less, or 200 nm or less.

[0076] The number average fiber length (L) / number average fiber diameter (D) ratio of the cellulose fiber raw material is preferably 30 or more, or 50 or more, or 80 or more, or 100 or more, or 120 or more, or 150 or more from the viewpoint of improving the mechanical properties of the resin composition well with a small amount of cellulose fiber. The upper limit is not particularly limited, but is preferably 5000 or less, or 3000 or less, or 2000 or less, or 1000 or less from the viewpoint of handleability.

[0077] In one aspect, the number average fiber diameter (D), number average fiber length (L), and L / D ratio of the cellulose fiber raw material of the present disclosure are values measured by the following procedure using a scanning electron microscope (SEM). The aqueous dispersion of the cellulose fiber raw material is replaced with tert-butanol, diluted to 0.001 to 0.1% by mass, and using a high-shear homogenizer (for example, manufactured by IKA, trade name "Ultra Turrax T18"), treatment conditions: rotate at 15,000 rpm for 3 minutes for dispersion, cast on an osmium-evaporated silicon substrate, and air-dried to obtain a measurement sample, which is measured with a high-resolution scanning electron microscope (SEM). Specifically, in an observation field with the magnification adjusted so that at least 100 fibrous substances are observed, the lengths (L) and diameters (D) of 100 randomly selected fibrous substances are measured, and the ratio (L / D) is calculated. For the cellulose fiber raw material, the number average value of the length (L), the number average value of the diameter (D), and the number average value of the ratio (L / D) are calculated.

[0078] [BET specific surface area] In one aspect, the BET specific surface area of the cellulose fiber is preferably 2 m 2 / g or more, preferably 3 m 2 / g or more, preferably 5 m 2 / g or more, preferably 7 m 2 / g or more, preferably 10 m 2 / g or more, preferably 12 m 2 / g or more, preferably 15 m 2 / g or more, preferably 17 m 2 / g or more, preferably 20 m 2 / g or more, preferably 22m 2 / g or more, preferably 25m 2 / g or more, preferably 27m 2 It is 1 / g or more. Furthermore, the BET specific surface area is preferably 400 m² from the viewpoint of good dispersion of cellulose fibers in the resin composition and ease of manufacturing the dried cellulose fiber product. 2 / g or less, preferably 350m 2 / g or less, preferably 300m 2 Less than or equal to 250mg / g, preferably 250mg 2 / g or less, preferably 200m 2 / g or less, preferably 170m 2 / g or less, preferably 150m 2 / g or less, preferably 120m 2 / g or less, preferably 100m 2 The specific surface area is less than or equal to 1 / g. The specific surface area is measured using nitrogen gas with a specific surface area and pore distribution analyzer (e.g., Nova-4200e, manufactured by Quantachrome Instruments) for porous cellulose fiber sheets. Specifically, after drying approximately 0.2 g of the porous sheet under vacuum at 120°C for 5 hours, the amount of nitrogen gas adsorbed at the boiling point of liquid nitrogen is measured at 5 points (multi-point method) within the range of relative vapor pressure (P / P0) of 0.05 to 0.2, and then the BET specific surface area (m²) is calculated using the instrument's program. 2 Calculate the amount per g. The procedure for preparing the porous sheet will be described later in the [Porous Sheet] section.

[0079] The specific surface area of ​​a cellulose fiber can be converted to its equivalent fiber diameter using the following formula, by assuming the cellulose fiber is cylindrical.

[0080] The density of cellulose is 1.5 (g / cm³). 3 Therefore, the volume per gram of cellulose is 6.7 × 10 -7 (m 3 The ratio is ( / g). If the equivalent fiber diameter of the cellulose fiber is r (m), then the average outer circumference of the cellulose fiber = πr and the average cross-sectional area of ​​the cellulose fiber = 0.25πr 2 Therefore, per gram of cellulose fiber, the total fiber length = 6.7 × 10 -7 (m 3 / g) / average cross-sectional area (=0.25πr 2 ) Total surface area = Specific surface area (m 2 ( / g) = 6.7 × 10 -7 (m 3 / g) / average cross-sectional area (=0.25πr 2 )×average outer circumference length (=πr)=6.7×10 -7 (m 3 / g) / 0.25r = 26.68 × 10 -7 (m 3 ( / g) / r Therefore, the equivalent fiber diameter r (m) = 26.68 × 10 -7 (m 3 / g) / specific surface area (m 2 ( / g) For example, if the BET specific surface area of ​​a porous sheet is 40 m² 2 The equivalent fiber diameter r of the cellulose fiber is calculated to be 66.7 nm.

[0081] In one embodiment, the equivalent fiber diameter of the cellulose fiber is preferably 2 to 5000 nm from the viewpoint of obtaining a good effect of improving physical properties by the cellulose fiber. More preferably, the equivalent fiber diameter of the cellulose fiber is 4 nm or more, or 5 nm or more, or 10 nm or more, or 15 nm or more, or 20 nm or more, and more preferably 3000 nm or less, or 1000 nm or less, or 900 nm or less, or 800 nm or less, or 700 nm or less, or 600 nm or less, or 500 nm or less, or 400 nm or less, or 300 nm or less, or 200 nm or less.

[0082] [Crystallization] The crystallinity of the cellulose fibers is preferably 55% or higher. When the crystallinity is within this range, the mechanical properties (strength, dimensional stability) of the cellulose itself are high, so when the cellulose fibers are dispersed in the resin, the strength and dimensional stability of the resin composition tend to be high. A more preferable lower limit for the crystallinity is 60%, even more preferably 70%, and most preferably 80%. There is no particular upper limit for the crystallinity of the cellulose fibers, and a higher value is preferable, but from a production standpoint, a preferable upper limit is 99%. On the other hand, if the crystallinity is low, the retention of the dispersant by the cellulose fibers becomes good, and the dispersant may not bleed out of the resin composition easily. From this viewpoint, in one embodiment, the crystallinity can be 99% or less, 95% or less, or 90% or less.

[0083] The degree of crystallinity referred to here, when the cellulose is a type I cellulose crystal (derived from natural cellulose), is determined by the Segal method from the diffraction pattern (2θ / deg. is 10 to 30) obtained by wide-angle X-ray diffraction of the sample, using the following formula: Degree of crystallinity (%) = [I(200) - I(amorphous)] / I(200) × 100 I(200): Diffraction peak intensity at the 200 plane (2θ = 22.5°) in the type I cellulose crystal I(amorphous): Halo peak intensity due to amorphous material in the type I cellulose crystal, at a peak angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°)

[0084] Furthermore, if the cellulose is a type II cellulose crystal (derived from regenerated cellulose), the degree of crystallinity can be determined by the following formula using wide-angle X-ray diffraction, based on the absolute peak intensity h0 at 2θ = 12.6°, which is attributed to the (110) plane peak of the type II cellulose crystal, and the peak intensity h1 from the baseline at this interplanar spacing: Degree of crystallinity (%) = h1 / h0 × 100

[0085] [Crystalline Polymorphism] As for the crystalline polymorphisms of cellulose, types I, II, III, and IV are known, and among them, types I and II are particularly widely used, while types III and IV are obtained on a laboratory scale but are not widely used on an industrial scale. As for the cellulose fibers of this disclosure, cellulose fibers containing cellulose type I crystals or cellulose type II crystals are preferred, and cellulose fibers containing cellulose type I crystals and having a degree of crystallinity of 55% or more are more preferred, as they have relatively high structural mobility and, by dispersing these cellulose fibers in a resin, a resin composition with a lower coefficient of linear expansion and superior strength and elongation during tensile and bending deformation can be obtained.

[0086] [Degree of Polymerization] The degree of polymerization of the cellulose fibers is preferably 100 or more, more preferably 150 or more, more preferably 200 or more, more preferably 300 or more, more preferably 400 or more, more preferably 450 or more, preferably 3500 or less, more preferably 3300 or less, more preferably 3200 or less, more preferably 3100 or less, and more preferably 3000 or less.

[0087] From the viewpoint of processability and mechanical property development, it is desirable to keep the degree of polymerization of the cellulose fibers within the above-mentioned range. From the viewpoint of processability, it is preferable that the degree of polymerization is not too high, and from the viewpoint of mechanical property development, it is desirable that it is not too low.

[0088] The degree of polymerization of cellulose fibers refers to the average degree of polymerization measured according to the reduction ratio viscosity method using copper ethylenediamine solution, as described in the confirmation test (3) of the "Fifteenth Revised Japanese Pharmacopoeia Commentary (published by Hirokawa Shoten)".

[0089] [Mw, Mn, Mw / Mn] In one embodiment, the weight-average molecular weight (Mw) of the cellulose fiber is 100,000 or more, or 200,000 or more. In one embodiment, the ratio of the weight-average molecular weight to the number-average molecular weight (Mn) (Mw / Mn) is 6 or less, or 5.4 or less. A larger weight-average molecular weight means fewer end groups in the cellulose molecule. Also, since the ratio of the weight-average molecular weight to the number-average molecular weight (Mw / Mn) represents the width of the molecular weight distribution, a smaller Mw / Mn means fewer end groups in the cellulose molecule. Since the end groups of the cellulose molecule are the starting points for thermal decomposition, a particularly heat-resistant cellulose fiber can be obtained when the weight-average molecular weight of the cellulose molecule in the cellulose fiber is large, and at the same time the width of the molecular weight distribution is narrow. From the viewpoint of the availability of cellulose fiber raw materials, the weight-average molecular weight (Mw) of the cellulose fiber may be, for example, 600,000 or less, or 500,000 or less. The ratio of weight-average molecular weight to number-average molecular weight (Mn) (Mw / Mn) may be, for example, 1.5 or more, or 2 or more, from the viewpoint of ease of manufacturing cellulose fibers. Mw can be controlled to the above range by selecting a cellulose fiber raw material having an Mw appropriate for the purpose, and by appropriately performing physical and / or chemical treatments on the cellulose fiber raw material within an appropriate range. Mw / Mn can also be controlled to the above range by selecting a cellulose fiber raw material having an Mw / Mn appropriate for the purpose, and by appropriately performing physical and / or chemical treatments on the cellulose fiber raw material within an appropriate range. In one embodiment, each of the Mw and Mw / Mn of the cellulose fiber raw material may be within the above range. In both the control of Mw and the control of Mw / Mn, examples of the above physical treatments include dry or wet grinding using microfluidizers, ball mills, disc mills, etc., and physical treatments that apply mechanical force such as impact, shear, shear, and friction using pulverizers, homomixers, high-pressure homogenizers, ultrasonic devices, etc. Examples of the above chemical treatments include pulverization, bleaching, acid treatment, enzymatic treatment, and regenerative cellulose formation.

[0090] The weight-average molecular weight and number-average molecular weight of cellulose fibers referred to herein are values ​​obtained by dissolving cellulose fibers in N,N-dimethylacetamide to which lithium chloride has been added, and then determining them by gel permeation chromatography using N,N-dimethylacetamide as the solvent.

[0091] [Control of Degree of Polymerization and Molecular Weight] Methods for controlling the degree of polymerization (i.e., average degree of polymerization) or molecular weight of cellulose fibers include hydrolysis. Hydrolysis promotes the depolymerization of amorphous cellulose inside the cellulose fibers, reducing the average degree of polymerization. At the same time, hydrolysis removes impurities such as hemicellulose and lignin in addition to the amorphous cellulose mentioned above, making the inside of the fibers porous. More specifically, a procedure similar to that described in Japanese Patent Application Publication No. 2024-031890 may be used.

[0092] [Alkali-soluble polysaccharides and acid-insoluble components] Alkali-soluble polysaccharides such as hemicellulose and acid-insoluble components such as lignin are present between the microfibrils of cellulose fibers and between the bundles of microfibrils. Hemicellulose is a polysaccharide composed of sugars such as mannan and xylan, and plays a role in linking microfibrils together by hydrogen bonding with cellulose. Lignin is a compound with an aromatic ring and is known to be covalently bonded with hemicellulose in the cell walls of plants.

[0093] The alkali-soluble polysaccharides that cellulose fibers may contain include not only hemicellulose but also β-cellulose and γ-cellulose. Alkali-soluble polysaccharides are understood by those skilled in the art to be components obtained as the alkali-soluble portion of holocellulose obtained by solvent extraction and chlorine treatment of plants (e.g., wood) (i.e., components obtained by removing α-cellulose from holocellulose). Since alkali-soluble polysaccharides are polysaccharides containing hydroxyl groups and have poor heat resistance, they can cause problems such as decomposition when heated, yellowing during thermal aging, and a decrease in the strength of cellulose fibers. Therefore, it is preferable to have a low alkali-soluble polysaccharide content in cellulose fibers.

[0094] In one embodiment, the average content of alkali-soluble polysaccharides in cellulose fibers is preferably 20% by mass or less, 18% by mass or less, 15% by mass or less, or 12% by mass or less, based on 100% by mass of cellulose fibers, from the viewpoint of maintaining the mechanical strength of the cellulose fibers during melt kneading and suppressing yellowing. The above content may be 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, from the viewpoint of ease of manufacturing the cellulose fibers.

[0095] The average alkali-soluble polysaccharide content can be determined using the method described in non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000), by subtracting the α-cellulose content from the holocellulose content (Wise method). This method is understood in this industry as a method for measuring hemicellulose content. The alkali-soluble polysaccharide content is calculated three times for each sample, and the number average of the calculated alkali-soluble polysaccharide content is taken as the average alkali-soluble polysaccharide content.

[0096] Acid-insoluble components that cellulose fibers may contain are understood by those skilled in the art as insoluble components remaining after sulfuric acid treatment of a degreased sample obtained by solvent extraction of plants (e.g., wood). Specifically, these acid-insoluble components are, but are not limited to, aromatic lignin. Acid-insoluble components are often colored themselves, which can impair the appearance of 3D printing materials and cause yellowing during thermal aging. Therefore, it is preferable to have a low average content of acid-insoluble components in cellulose fibers.

[0097] In one embodiment, the average content of acid-insoluble components in cellulose fibers is preferably 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on 100% by mass of cellulose fibers, from the viewpoint of avoiding a decrease in the heat resistance of cellulose fibers and the resulting discoloration. From the viewpoint of ease of manufacturing cellulose fibers, the above content may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more.

[0098] The average acid-insoluble component content is determined using the Claesson method described in the non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000). This method is understood in this industry as a method for measuring lignin content. After stirring the sample in sulfuric acid solution to dissolve cellulose and hemicellulose, etc., the sample is filtered through glass fiber filter paper, and the resulting residue contains the acid-insoluble components. The acid-insoluble component content is calculated from the weight of these acid-insoluble components, and the average of the number of acid-insoluble component content calculated for three samples is taken as the average acid-insoluble component content.

[0099] [Thermal decomposition start temperature (T D )] The thermal decomposition onset temperature of cellulose fibers (T D From the viewpoint of avoiding thermal degradation during melt-kneading and being able to exhibit mechanical strength, the temperature is preferably 250°C or higher, or 260°C or higher, or 270°C or higher, or 275°C or higher, or 280°C or higher, or 285°C or higher in one embodiment. A higher thermal decomposition onset temperature is preferable, but from the viewpoint of ease of manufacturing cellulose fibers, it may be, for example, 320°C or lower, or 310°C or lower, or 300°C or lower.

[0100] [Temperature at 1% weight loss (T 1% ), 250℃ weight loss rate (T 250℃ )] Temperature (T) when cellulose fiber loses 1 wt% of its weight 1% In one embodiment, the temperature is preferably 260°C or higher, or 270°C or higher, or 275°C or higher, or 280°C or higher, or 285°C or higher, or 290°C or higher, from the viewpoint of avoiding thermal degradation during melting and kneading and being able to exhibit mechanical strength. 1% Higher temperatures are preferable, but from the viewpoint of ease of manufacturing cellulose fibers, temperatures of, for example, 330°C or lower, 320°C or lower, or 310°C or lower may also be acceptable.

[0101] Weight loss rate of cellulose fibers at 250°C (T 250℃ From the viewpoint of avoiding thermal degradation during melting and kneading and being able to exhibit mechanical strength, in one embodiment, it is preferably 15% or less, or 12% or less, or 10% or less, or 8% or less, or 6% or less, or 5% or less, or 4% or less, or 3% or less. 250℃While a lower value is preferable, from the viewpoint of ease of manufacturing cellulose fibers, it may be, for example, 0.1% or more, or 0.5% or more, or 0.7% or more, or 1.0% or more.

[0102] In this disclosure, T D This value is obtained from a graph in thermogravimetric (TG) analysis under nitrogen flow, where the x-axis is temperature and the y-axis is weight retention percentage. Cellulose fibers are heated from room temperature to 150°C at a rate of 10°C / min in a nitrogen flow of 100 ml / min, held at 150°C for 1 hour, and then heated to 450°C at a rate of 10°C / min. The weight at 150°C (when moisture is almost completely removed) (weight loss of 0 wt%) is used as the starting point, and the temperature (T) at which a 1 wt% weight loss occurs is used. 1% ) and temperature (T) when weight decreases by 2 wt% 2% Obtain a straight line passing through ( ). The temperature at the point where this straight line intersects with the horizontal line (baseline) passing through the starting point of the weight loss of 0 wt% is T. D This is how it is defined.

[0103] 1% weight loss temperature (T 1% ) is the above T D This is the temperature at which the weight decreases by 1% by weight, starting from the weight at 150°C, when the temperature is continuously increased using this method.

[0104] Weight loss rate of cellulose fibers at 250°C (T 250℃ The weight change rate (%) at 250°C is the percentage of weight loss when cellulose fibers are held at 250°C under a nitrogen flow for 2 hours, as determined by TG analysis. Cellulose fibers are heated from room temperature to 150°C at a rate of 10°C / min in a nitrogen flow of 100 ml / min, held at 150°C for 1 hour, then heated from 150°C to 250°C at a rate of 10°C / min, and held at 250°C for 2 hours. The weight W0 at the time of reaching 250°C is taken as the starting point, and the weight after holding at 250°C for 2 hours is taken as W1. The weight change rate (%) at 250°C is calculated using the following formula: (W1 - W0) / W0 × 100

[0105] [Porous Sheet] Various properties of cellulose fibers (specific surface area, degree of crystallinity, polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, average content of alkali-soluble polysaccharides, average content of acid-insoluble components, T D , T 1% , T250℃ Measurements of (etc.) can vary significantly depending on the form of the sample being measured. To ensure stable and reproducible measurements, a distortion-free porous sheet should be used as the measurement sample. The method for preparing the porous sheet is as follows.

[0106] First, a concentrated cellulose fiber cake with a solid content of 10% by mass or more, where water is the liquid medium, is added to tert-butanol. Further dispersion is performed using a mixer or similar device (for example, a high-shear homogenizer (e.g., IKA product, product name "Ultra-Turrax T18", processing conditions: rotation speed 15,000 rpm x 3 minutes)) until no aggregates remain. The concentration is adjusted to 0.5% by mass for every 0.5 g of cellulose fiber solid content. 100 g of the resulting tert-butanol dispersion is filtered on filter paper. Without removing the filtrate from the filter paper, it is sandwiched between two larger sheets of filter paper, and the edges of the larger sheets are pressed down with weights, and dried in a 150°C oven for 5 minutes. After that, the filter paper is peeled off to obtain a porous sheet with minimal distortion. The air permeability resistance R of this sheet is 10 g / m² of sheet basis weight. 2 Materials with a density of 100 sec / 100 ml or less are treated as porous sheets and used as measurement samples.

[0107] The air permeability resistance R was measured by the basis weight W (g / m²) of a porous sheet sample that had been left standing for one day in an environment of 23°C and 50% RH. 2 After measuring the air permeability resistance (R) (sec / 100ml), the air permeability resistance is measured using a Wangyan-type air permeability resistance tester (for example, Asahi Seiko Co., Ltd., model EG01). At this time, 10 g / m³ is used according to the following formula. 2 Calculate the value per unit weight. 10 g / m² 2 Air permeability resistance (sec / 100ml) = R / W × 10

[0108] [Physical properties of cellulose fibers in thermoplastic elastomer resin compositions] Various physical properties of cellulose fibers in thermoplastic elastomer resin compositions (number average fiber length, number average fiber diameter, L / D ratio, degree of crystallinity, crystalline polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, average content of alkali-soluble polysaccharides, average content of acid-insoluble components, T D , T 1% , T 250℃The properties of the cellulose fibers in the thermoplastic elastomer resin composition (including DS, DSs, DS heterogeneity ratio, coefficient of variation of the DS heterogeneity ratio, etc., as described later) are analyzed by the following method. The thermoplastic elastomer is dissolved in an organic or inorganic solvent capable of dissolving the thermoplastic elastomer component of the thermoplastic elastomer resin composition, the cellulose fibers are separated, and after thorough washing with the solvent, the solvent is replaced with tert-butanol. Subsequently, the cellulose fiber tert-butanol slurry is analyzed using the same measurement method as described above, and various physical properties of the cellulose fibers in the thermoplastic elastomer resin composition are calculated.

[0109] The amount of cellulose fibers per 100 parts by mass of thermoplastic elastomer is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 3 parts by mass or more, or 5 parts by mass or more, or 7 parts by mass or more, or 10 parts by mass or more, from the viewpoint of improving physical properties by cellulose fibers, and preferably 150 parts by mass or less, or 100 parts by mass or less, or 80 parts by mass or less, or 50 parts by mass or less, or 30 parts by mass or less, or 20 parts by mass or less, from the viewpoint of moldability and flexibility.

[0110] <Other Components> In addition to the thermoplastic elastomer and cellulose fibers described above, the thermoplastic elastomer resin composition of this embodiment may contain other components such as additives as needed. Examples of such additives include colorants, anti-aging agents, antioxidants, weathering agents, metal deactivators, light stabilizers, heat stabilizers, ultraviolet absorbers, antibacterial and antifungal agents, deodorants, conductivity imparters, dispersants, softeners, plasticizers, crosslinking agents, co-crosslinking agents, vulcanizing agents, vulcanizing aids, foaming agents, foaming aids, flame retardants, vibration damping agents, nucleating agents, neutralizing agents, lubricants, anti-blocking agents, dispersants, fluidity improvers, and mold release agents.

[0111] [Colorants] Examples of the above colorants include carbon black, nigrosine, aluminum pigment, titanium dioxide, ultramarine, cyanine blue, cyanine green, quinacridone, diatomaceous earth, monoazo salts, perylene, disazo, condensed azo, isoindoline, red iron oxide, nickel titanium yellow, diketone pyrrolopyrrole, metal salts, perylene red, metal oxides, bismuth vanadate, cobalt green, cobalt blue, anthraquinone, phthalocyanine green, phthalocyanine blue, etc.

[0112] When a thermoplastic elastomer resin composition contains carbon black, it is possible to further improve the wire diameter stability and molding stability of the thermoplastic elastomer resin composition, as well as further improve properties such as heat resistance, UV resistance, vacuum resistance, and radiation resistance. Therefore, the thermoplastic elastomer resin composition of this embodiment, which further contains carbon black, and the molded objects obtained using it can be suitably used, for example, in the manufacture of space equipment such as artificial satellites.

[0113] When the thermoplastic elastomer resin composition contains carbon black, the carbon black content is preferably 0.2% by mass or more relative to the total mass of the thermoplastic elastomer resin composition. In this case, it is possible to obtain a good effect of further improving the wire diameter stability and molding stability of the thermoplastic elastomer resin composition, as well as further improving properties such as heat resistance, ultraviolet resistance, vacuum resistance, and radiation resistance. Furthermore, when the thermoplastic elastomer resin composition of this embodiment contains carbon black, the carbon black content is preferably 5.0% by mass or less relative to the total mass of the thermoplastic elastomer resin composition. In this case, for example, when the thermoplastic elastomer resin composition of this embodiment is used in the manufacture of space equipment such as artificial satellites, it is possible to suppress overheating due to the effects of infrared radiation in outer space. From a similar viewpoint, the carbon black content is more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, even more preferably 4.5% by mass or less, and even more preferably 4.0% by mass or less, relative to the total mass of the thermoplastic elastomer resin composition.

[0114] If the thermoplastic elastomer resin composition of this embodiment contains additives other than carbon black, the content of such additives may be, for example, 3% by mass or less, preferably 1.5% by mass or less, based on the total mass (100% by mass) of the thermoplastic elastomer resin composition.

[0115] [Liquid Polymer] In one embodiment, the thermoplastic elastomer resin composition may contain a liquid polymer. A liquid polymer means a polymer that is fluid at 23°C. In one embodiment, the liquid polymer has a glass transition temperature (Tg). In one embodiment, the liquid polymer may be a conjugated diene polymer or a non-conjugated diene polymer. In one embodiment, the liquid polymer is liquid rubber. In this disclosure, liquid rubber means a substance that is fluid at 23°C and forms a rubber elastic body by crosslinking (more specifically vulcanization) and / or chain extension. That is, in one embodiment, the liquid rubber is an uncured product.

[0116] Furthermore, having fluidity means, in one embodiment, that a liquid polymer dissolved in cyclohexane is placed in a vial measuring 21 mm in diameter and 50 mm in length at 23°C and then dried, so that the vial is filled to a height of 1 mm with the liquid polymer and sealed, and when the vial is left standing upside down for 24 hours, a movement of 0.1 mm or more of the substance in the height direction can be observed.

[0117] The liquid polymer may have the monomer composition of a general polymer, and is preferably relatively low in molecular weight from the viewpoint of ease of handling and good dispersibility of cellulose fibers. In one embodiment, the liquid polymer exhibits liquid form by having a number-average molecular weight (Mn) of 80,000 or less. Unless otherwise specified, the number-average molecular weight and weight-average molecular weight of the various polymers in this disclosure are values ​​obtained in terms of standard polystyrene using gel permeation chromatography with chloroform as the solvent and a measurement temperature of 40°C.

[0118] In one embodiment, a liquid polymer may be combined with cellulose fibers to form a masterbatch, and such a masterbatch may be combined with a thermoplastic elastomer to form the thermoplastic elastomer resin composition of the present disclosure.

[0119] The number-average molecular weight (Mn) of the liquid polymer is preferably 1,000 or more, or 1,500 or more, or 2,000 or more, from the viewpoint of thermal stability and the effect of improving the dispersibility of cellulose fibers in thermoplastic elastomers. It is preferably 80,000 or less, or 50,000 or less, or 40,000 or less, or 30,000 or less, or 10,000 or less, in terms of having high fluidity suitable for good dispersion when dispersing cellulose fibers in the liquid polymer.

[0120] The weight-average molecular weight (Mw) of the liquid polymer is preferably 1,000 or more, 2,000 or more, or 4,000 or more, from the viewpoint of thermal stability and the effect of improving the dispersibility of cellulose fibers in thermoplastic elastomers, and preferably 240,000 or less, 150,000 or less, or 30,000 or less, in terms of having high fluidity suitable for good dispersion when dispersing cellulose fibers in liquid polymers.

[0121] The ratio (Mw / Mn) of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) of the liquid polymer is preferably 1.5 or higher, or 1.8 or higher, or 2 or higher, in that the degree of variation in molecular weight allows for a high degree of compatibility of multiple properties (in one embodiment, a high degree of compatibility between good dispersion of cellulose fibers in the thermoplastic elastomer and a good flexural modulus of the thermoplastic elastomer resin composition). In that the variation in molecular weight is not excessively large and the desired physical properties of the thermoplastic elastomer resin composition can be obtained stably, for example, in terms of compatibility between fluidity and impact resistance, it is preferably 10 or lower, or 8 or lower, or 5 or lower, or 3 or lower, or 2.7 or lower.

[0122] Liquid polymers can have good thermal stability. The thermal decomposition onset temperature of liquid polymers (T D In terms of good thermal stability, the temperature is, in one embodiment, above 200°C, or 210°C or above, or 230°C or above, or 250°C or above, or 300°C or above. A higher thermal decomposition onset temperature is preferable, but from the viewpoint of the availability of the liquid polymer, in one embodiment it may be 500°C or below, or 450°C or below, or 400°C or below.

[0123] The glass transition temperature of the liquid polymer is preferably -150°C or higher, or -120°C or higher, or -100°C or higher, in terms of good thermal stability, and preferably 25°C or lower, or 10°C or lower, or 0°C or lower, in terms of good fluidity.

[0124] In one embodiment, the liquid polymer comprises a diene polymer, and in another embodiment, a conjugated diene polymer or a non-conjugated diene polymer or hydrogenated thereof. The above polymer or its hydrogenated counterpart may be an oligomer. The monomers constituting the liquid polymer may be unmodified or modified (e.g., acid-modified, hydroxyl-modified, etc.). In one embodiment, the liquid polymer may have reactive groups at both ends (e.g., one or more selected from the group consisting of hydroxyl groups, carboxyl groups, isocyanate groups, thio groups, amino groups, and halo groups), and therefore may be bifunctional. These reactive groups contribute to crosslinking and / or chain extension of the liquid polymer.

[0125] (Conjugated diene polymers) Conjugated diene polymers may be homopolymers, or copolymers of two or more conjugated diene monomers, or copolymers of a conjugated diene monomer with another monomer. The copolymer may be random or block.

[0126] Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, which may be used individually or in combination of two or more.

[0127] In one embodiment, the conjugated diene polymer is a copolymer of the above-mentioned conjugated diene monomer and an aromatic vinyl monomer. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with the conjugated diene monomer, and examples include styrene, m or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinyl xylene, vinyl naphthalene, diphenylethylene, and divinylbenzene, which may be used individually or in combination of two or more. From the viewpoint of moldability of the thermoplastic elastomer resin composition and impact resistance of the molded article, styrene is preferred.

[0128] Examples of random copolymers include butadiene-isoprene random copolymers, butadiene-styrene random copolymers, isoprene-styrene random copolymers, and butadiene-isoprene-styrene random copolymers. Examples of the compositional distribution of each monomer in the copolymer chain include perfectly random copolymers with a composition close to statistically random, and tapered random copolymers with a gradient in the compositional distribution. The bonding mode of the conjugated diene polymer, i.e., the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or different between molecules.

[0129] A block copolymer may be a copolymer consisting of two or more blocks. For example, a block copolymer may have a structure such as A-B, A-B-A, A-B-A-B, etc., where block A is an aromatic vinyl monomer and block B is a block of conjugated diene monomer and / or a copolymer of aromatic vinyl monomer and conjugated diene monomer. The boundaries of each block do not necessarily need to be clearly distinguishable; for example, if block B is a copolymer of aromatic vinyl monomer and conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or in a tapered manner. Furthermore, block B may have multiple portions where the aromatic vinyl monomer is uniformly distributed and / or distributed in a tapered manner. In addition, block B may have multiple segments with different aromatic vinyl monomer content. When multiple blocks A and block B exist in the copolymer, their molecular weights and compositions may be the same or different.

[0130] The block copolymer may be a mixture of two or more types in which one or more of the following are different: bond type, molecular weight, aromatic vinyl compound species, conjugated diene compound species, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc.

[0131] The amount of vinyl bonds in the conjugated diene bond units of a conjugated diene polymer (e.g., 1,2- or 3,4-bonds in butadiene) is preferably 10 mol% to 75 mol%, or 13 mol% to 65 mol%. The amount of vinyl bonds in the conjugated diene bond units (e.g., the amount of 1,2-bonds in butadiene) can be determined by 13C-NMR (quantitative mode). That is, by integrating the peak areas that appear below in 13C-NMR, a value proportional to the carbon content of each structural unit can be obtained, and as a result, it can be converted to the mass percentage of each structural unit. Styrene 145-147 ppm Vinyl 110-116 ppm Diene (cis) 24-28 ppm Diene (trans) 29-33 ppm

[0132] In a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of aromatic vinyl monomer bonded to the conjugated diene monomer (hereinafter also referred to as the amount of aromatic vinyl bonded) may preferably be 5 mol% to 70 mol%, or 10 mol% to 50 mol%, based on 100% of the total moles of the conjugated diene polymer.

[0133] Examples of hydrogenated conjugated diene polymers include those exemplified above, such as hydrogenated butadiene homopolymers, isoprene homopolymers, styrene-butadiene copolymers, and acrylonitrile-butadiene copolymers.

[0134] In a preferred embodiment, the liquid polymer is one or more selected from the group consisting of polybutadiene, butadiene-styrene copolymer, polyisoprene, and polychloroprene. These may be derivatives (e.g., maleic anhydride modified, methacrylic acid modified, terminal hydroxyl group modified, hydrogenated, and combinations thereof).

[0135] (Non-conjugated diene polymers) Non-conjugated diene polymers may be homopolymers, or copolymers of two or more non-conjugated diene monomers, or copolymers of a non-conjugated diene monomer with another monomer. The copolymer may be random or block. Examples of non-conjugated diene polymers include olefin polymers (e.g., liquid paraffin), silicone polymers, acrylic polymers, etc. For example, when the liquid polymer is liquid rubber, examples of non-conjugated diene polymers include olefin polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, and ethylene-α-olefin copolymers, as well as butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, etc.

[0136] In ethylene-α-olefin copolymers, monomers that can copolymerize with ethylene units include propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, or eicosene-1, aliphatic substituted vinyl monomers such as isobutylene, and styrene. Examples include aromatic vinyl monomers such as substituted styrene, vinyl acetate, acrylic acid esters, methacrylic acid esters, glycidyl acrylic acid esters, glycidyl methacrylic acid esters, hydroxyethyl methacrylic acid esters, nitrogen-containing vinyl monomers such as acrylamide, allylamine, vinyl-p-aminobenzene, and acrylonitrile, and dienes such as butadiene, cyclopentadiene, 1,4-hexadiene, and isoprene.

[0137] The ethylene-α-olefin copolymer is preferably a copolymer of ethylene and one or more α-olefins having 3 to 20 carbon atoms, more preferably a copolymer of ethylene and one or more α-olefins having 3 to 16 carbon atoms, and most preferably a copolymer of ethylene and one or more α-olefins having 3 to 12 carbon atoms.

[0138] From the viewpoint of exhibiting impact resistance, the molecular weight of the ethylene-α-olefin copolymer is preferably 10,000 or more, more preferably 10,000 to 100,000, more preferably 10,000 to 80,000, and even more preferably 20,000 to 60,000, as measured by gel permeation chromatography using 1,2,4-trichlorobenzene as a solvent at 140°C with a polystyrene standard.

[0139] Furthermore, from the viewpoint of ease of handling during processing, the ethylene unit content of the ethylene-α-olefin copolymer is preferably 30 to 95% by mass relative to the total amount of the ethylene-α-olefin copolymer.

[0140] Ethylene-α-olefin copolymers can be produced by conventionally known manufacturing methods, such as those described in Japanese Patent Publication No. 4-12283, Japanese Unexamined Patent Publication No. 60-35006, Japanese Unexamined Patent Publication No. 60-35007, Japanese Unexamined Patent Publication No. 60-35008, Japanese Unexamined Patent Publication No. 5-155930, Japanese Unexamined Patent Publication No. 3-163088, and U.S. Patent No. 5,272,236.

[0141] In one embodiment, the liquid polymer comprises one or more selected from the group consisting of diene rubber, silicone rubber, urethane rubber, and polysulfide rubber, and hydrogenated versions thereof, and preferably comprises diene rubber.

[0142] The viscosity of the liquid polymer at 25°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 200,000 mPa·s or less, from the viewpoint of good dispersion of cellulose fibers in the liquid polymer, and preferably 100 mPa·s or more, or 300 mPa·s or more, or 500 mPa·s or more, from the viewpoint of thermal stability, effect of improving the dispersibility of cellulose fibers in the thermoplastic elastomer, and mechanical properties of the thermoplastic elastomer resin composition.

[0143] The viscosity of the liquid polymer at 50°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 200,000 mPa·s or less, or 100,000 mPa·s or less, from the viewpoint of good dispersion of cellulose fibers in the liquid polymer and good dispersion of cellulose fibers in the thermoplastic elastomer by heating and kneading. From the viewpoint of thermal stability, effect on improving the dispersibility of cellulose fibers in the thermoplastic elastomer, and mechanical properties of the thermoplastic elastomer resin composition, it is preferably 50 mPa·s or more, or 100 mPa·s or more, or 500 mPa·s or more.

[0144] The viscosity of the liquid polymer at 80°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 250,000 mPa·s or less, or 100,000 mPa·s or less, from the viewpoint of good dispersion of cellulose fibers in the liquid polymer and good dispersion of cellulose fibers in the thermoplastic elastomer by heating and kneading. From the viewpoint of thermal stability, effect on improving the dispersibility of cellulose fibers in the thermoplastic elastomer, and mechanical properties of the thermoplastic elastomer resin composition, it is preferably 50 mPa·s or more, or 100 mPa·s or more, or 300 mPa·s or more.

[0145] The viscosity of the liquid polymer at 0°C is preferably 2,000,000 mPa·s or less, or 1,000,000 mPa·s or less, or 400,000 mPa·s or less, from the viewpoint of good dispersion of cellulose fibers in the liquid polymer, and preferably 200 mPa·s or more, or 600 mPa·s or more, or 1,000 mPa·s or more, from the viewpoint of thermal stability, effect of improving the dispersibility of cellulose fibers in the thermoplastic elastomer, and mechanical properties of the thermoplastic elastomer resin composition.

[0146] It is preferable that the viscosity of the liquid polymer at 80°C, 50°C, 25°C, and 0°C is all within the above range, as this allows for good dispersion of cellulose fibers in the liquid polymer over a wide mixing temperature range.

[0147] The viscosity of a liquid polymer is measured using a B-type viscometer at a rotation speed of 10 rpm.

[0148] In a thermoplastic elastomer resin composition, the amount of liquid polymer relative to 100 parts by mass of thermoplastic elastomer (in one embodiment, 100 parts by mass of styrene-based elastomer) is preferably 0.1 parts by mass or more, or 0.3 parts by mass or more, or 0.5 parts by mass or more, from the viewpoint of obtaining the advantages of the liquid polymer well, and preferably 15 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less, from the viewpoint of obtaining the advantages of acid-modified styrene-based elastomer well.

[0149] In a thermoplastic elastomer resin composition, the amount of liquid polymer per 100 parts by mass of cellulose fiber is preferably 5 parts by mass or more, or 10 parts by mass or more, or 20 parts by mass or more, or 30 parts by mass or more, or 40 parts by mass or more, from the viewpoint of obtaining good advantages of the liquid polymer, and preferably 400 parts by mass or less, or 200 parts by mass or less, or 100 parts by mass or less, from the viewpoint of obtaining good physical properties of the thermoplastic elastomer resin composition and the molded product.

[0150] From the viewpoint of obtaining the advantages of liquid polymers well, the liquid polymer content in the thermoplastic elastomer resin composition is preferably 0.1% by mass or more, or 0.3% by mass or more, or 1.0% by mass or more. From the viewpoint of obtaining good physical properties of the thermoplastic elastomer resin composition and the molded product, it is preferably 20% by mass or less, or 10% by mass or less, or 7% by mass or less, or 5% by mass or less.

[0151] [Dispersant] In one embodiment, the thermoplastic elastomer resin composition includes a dispersant. In one embodiment, it is even more preferable that the dispersant has a hydrophilic segment and a hydrophobic segment within the same molecule (i.e., is an amphiphilic molecule) in terms of more uniformly dispersing cellulose fibers in the thermoplastic elastomer resin composition. In a preferred embodiment, the thermoplastic elastomer resin composition includes a polyoxyethylene unit-containing polymer.

[0152] (Amphiphilic Molecules) In amphiphilic molecules, the hydrophilic segment is the part that exhibits good affinity with cellulose fibers by containing a hydrophilic structure. Specifically, hydrophilic structures include hydroxyl groups, thiol groups, carboxyl groups, sulfonic acid groups, sulfate ester groups, phosphate groups, boronic acid groups, silanol groups, groups derived from sugars such as sorbitan and sucrose, groups derived from glycerin, groups represented by -OM, -COOM, -SO3M, -OSO3M, -HMPO4, and -M2PO4 (where M represents an alkali metal or alkaline earth metal), as well as primary to tertiary amines and quaternary ammonium salts. Examples of counteranions for the above-mentioned quaternary ammonium salt include one or more hydrophilic groups selected from the group consisting of halogen ions such as hydroxide ions, fluoride ions, chloride ions, bromide ions, and iodide ions, as well as nitrate ions, formate ions, acetate ions, trifluoroacetate ions, p-toluenesulfonate ions, hexafluorophosphates, and tetrafluoroborates.

[0153] Examples of hydrophilic segments include polyethylene glycol segments, segments containing repeating units with quaternary ammonium salt structures, polyvinyl alcohol segments, polyvinylpyrrolidone segments, polyacrylic acid segments, carboxyvinyl polymer segments, cationized guar gum segments, hydroxyethylcellulose segments, methylcellulose segments, carboxymethylcellulose segments, and polyurethane soft segments (specifically diol segments). Nonionic polyoxyethylene derivatives are particularly preferred, and the polyoxyethylene chain length of the polyoxyethylene derivative may be 3 or more, or 5 or more, or 10 or more, or 15 or more. The longer the chain length, the higher the affinity with cellulose fibers, but from the viewpoint of balancing with the desired properties (e.g., mechanical properties) of the resin molded article, the polyoxyethylene chain length may be 60 or less, or 50 or less, or 40 or less, or 30 or less, or 20 or less.

[0154] Examples of hydrophobic segments include segments containing hydrocarbons, segments containing carbon fluoride, segments containing alkylene oxide units with 3 or more carbon atoms (e.g., PPG blocks), and segments containing polymer structures. Preferred hydrocarbon segments include alkyl types, alkenyl types, alkyl ether types, alkenyl ether types, alkylphenyl ether types, alkenylphenyl ether types, rosin ester types, bisphenol A types, β-naphthyl types, styrene-phenyl types, and hydrogenated castor oil types. The number of carbon atoms in the alkyl chain or alkenyl chain of the hydrophobic group (in the case of alkylphenyl or alkenylphenyl, the number of carbon atoms excluding the phenyl group) is preferably 2 or more, or 5 or more, or 10 or more, or 12 or more, or 16 or more. Preferred segments containing carbon fluoride include linear or branched alkyl types with 1 to 20 carbon atoms. Preferred polymer segments include acrylic polymers, styrene resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, amino acid lactams including ring-opening polymers of lactams, polymers composed of diamines and dicarboxylic acids, polyacetal resins, polycarbonate resins, polyester resins, polyphenylene sulfide resins, polysulfone resins, polyetherketone resins, polyimide resins, fluorine resins, hydrophobic silicone resins, melamine resins, epoxy resins, and phenolic resins. These hydrophobic segments may have either a linear or branched structure. Furthermore, the hydrophobic segments may have a single-chain structure or a structure of two or more chains, and if they have a structure of two or more chains, they may have multiple types of hydrophobic groups.

[0155] The structure of amphiphilic molecules is not particularly limited, but when the hydrophilic segment is A and the hydrophobic segment is B, examples include linear copolymers such as AB-type block copolymers, ABA-type block copolymers, and BAB-type block copolymers; tribranched copolymers containing A and B; tetrabranched copolymers containing A and B; star copolymers containing A and B; monocyclic copolymers containing A and B; polycyclic copolymers containing A and B; cage copolymers containing A and B; and graft copolymers containing A and B. When multiple hydrophilic segments are present in a molecule, the molecular structure of the hydrophilic segment may be a single type or a combination of two or more types. Similarly, when multiple hydrophobic segments are present in a molecule, the molecular structure may be a single type or a combination of two or more types.

[0156] (Surfactants) Any of the following can be used as amphiphilic molecules: anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. The dispersant may be a polymer surfactant, a reactive surfactant, etc.

[0157] Examples of nonionic surfactants include fatty acid dialkanolamides (e.g., lauric acid diethanolamide), polyoxyalkylene fatty acid amides (e.g., polyoxyethylene stearic acid amide), polyoxyalkylene aryl ethers (e.g., polyoxyethylene phenyl ether), polyoxyalkylene alkylaryl ethers (e.g., polyoxyethylene octylphenyl ether), polyoxyalkylene alkyl or alkenyl ethers (e.g., polyoxyethylene lauryl ether, polyoxyethylene stearyl ether), fatty acid esters of polyhydric alcohols (e.g., polyethylene glycol mono or distearate ester, polyethylene glycol mono or dilaurate ester, polyoxyethylene hydrogenated castor oil), glycerin fatty acid esters (e.g., glyceryl monostearate, glyceryl monooleate), sorbitan fatty acid esters (e.g., sorbitan monolaurylate, sorbitan monostearate), and polyoxyethylene-polyoxypropylene block polymers.

[0158] Anionic surfactants (emulsifiers) may be carboxylates, sulfonates, sulfate esters, phosphate esters, etc. Examples of carboxylates include aliphatic monocarboxylic acids and alkyl ether carboxylates; examples of sulfonates include dialkyl sulfosuccinates, alkanesulfonates, alkylbenzenesulfonates, and alkylnaphthalenesulfonates; examples of sulfate esters include alkyl sulfates and oil sulfates; and examples of phosphate esters include alkyl phosphates and polyoxyethylene alkyl ether phosphates.

[0159] Cationic surfactants include amine salts, amidoamine salts, quaternary ammonium salts, and imidazolinium salts. Specific examples, though not limited to them, include alkylamine salts, polyoxyethylene alkylamine salts, alkylamidoamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt-type surfactants such as imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, alkylisoquinolinium salts, and quaternary ammonium salt-type surfactants such as benzethonium chloride.

[0160] Examples of amphoteric surfactants include alkylamine oxides, alanines, imidazolinium betaines, amide betaines, and acetate betaine. Specifically, examples include long-chain amine oxides, lauryl betaine, stearyl betaine, laurylcarboxymethylhydroxyethylimidazolinium betaine, lauryldimethylaminoacetic acid betaine, and fatty acid amidopropyldimethylaminoacetic acid betaine.

[0161] (Hydrophilic Polymer) In one embodiment, the dispersant is preferably a hydrophilic polymer. In one embodiment, the hydrophilic polymer is a polymer having a hydrophilic group selected from the group consisting of hydroxyl groups, carboxyl groups, amino groups, ammonium groups, sulfonic acid groups, phosphate groups, etc. As the hydrophilic polymer, one or more selected from the group consisting of cellulose derivatives (hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, etc.), polyalkylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, carboxyvinyl polymer, cationized guar gum, water-soluble polyurethane, polymers containing quaternary ammonium salt structures, amides, amines, etc. can be used. Among these, cellulose derivatives and polyalkylene glycol are more preferred, and polyalkylene glycol is particularly preferred.

[0162] The amount of dispersant in the thermoplastic elastomer resin composition is preferably 1 part by mass or more, or 3 parts by mass or more, or 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more, per 100 parts by mass of cellulose fibers, and preferably 200 parts by mass or less, or 150 parts by mass or less, or 100 parts by mass or less, or 90 parts by mass or less, or 80 parts by mass or less, or 70 parts by mass or less, or 60 parts by mass or less, or 50 parts by mass or less.

[0163] The dispersant content in the thermoplastic elastomer resin composition components may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more in one embodiment, and may be 40% by mass or less, 35% by mass or less, or 30% by mass or less in one embodiment.

[0164] For example, when a preliminary composition containing cellulose fibers and an acid-modified styrene elastomer is used in the production of a thermoplastic elastomer resin composition, the mass ratio of the preliminary composition to a thermoplastic elastomer other than the acid-modified styrene elastomer (in one embodiment, a styrene elastomer) in the thermoplastic elastomer resin composition components (preliminary composition / thermoplastic elastomer (in one embodiment, styrene elastomer)) may, in one embodiment, be 1 / 99 to 99 / 1, or 5 / 95 to 95 / 5, or 10 / 90 to 90 / 10, or 20 / 80 to 80 / 20, or 30 / 70 to 70 / 30.

[0165] <Shape of Thermoplastic Elastomer Resin Composition> The thermoplastic elastomer resin composition of this embodiment can be provided in various shapes. Specifically, examples include filament shape, powder shape, pellet shape, plate shape, etc., but filament shape and pellet shape are preferred due to their ease of manufacture.

[0166] The filament diameter (longest diameter) of the filamentous material is preferably 0.5 to 5.0 mm, more preferably 1.0 to 3.5 mm, and most preferably 1.5 to 3.0 mm. The minimum value d1, average value d2, and maximum value d3 of the filament diameter preferably satisfy the following relationships: -9 ≤ (d1 - d2) / d2 × 100 ≤ 0 and 0 ≤ (d3 - d2) / d2 × 100 ≤ 9. From the viewpoint of molding stability, dimensional stability of the molded object, and voids in the molded object, the value of [(d1 - d2) / d2 × 100] is preferably -9 or greater, or -6 or greater, or -3 or greater, and the value of [(d3 - d2) / d2 × 100] is preferably 9 or less, or 6 or less, or 3 or less. The filament diameter is a value measured by the method described in the [Examples] section of this disclosure. The values ​​of (d1-d2) / d2×100 and (d3-d2) / d2×100 can be adjusted, for example, by appropriately setting the room temperature during filament manufacturing, the extruder temperature, and / or the winding speed.

[0167] The length of the filament material is preferably more than 1 m, more preferably more than 10 m, even more preferably more than 100 m, and most preferably more than 300 m. By controlling the shape of the filament material within this range, the degree of freedom in selecting conditions when using a 3D printer can be increased. Specifically, it becomes possible to appropriately design the printing time, the size of the printed object, and the precision. In one embodiment, the length of the filament material may be 20,000 m or less.

[0168] The arithmetic mean roughness Ra of the filamentous material is preferably 10 or more, or 20 or more, or 30 or more, or 40 or more. When the surface roughness of the filamentous material is within this range, it is easier to pull the filament out of the reel. From the viewpoint of dimensional accuracy of the molded object, the arithmetic mean roughness Ra may be 200 or less, or 150 or less. The arithmetic mean roughness Ra is a value measured in accordance with JIS B0601:2013, over an evaluation length of 4 mm in the longitudinal direction of the filamentous material.

[0169] In one embodiment, the filamentous material can be manufactured by heating and melting a thermoplastic elastomer raw material, then passing it through a pore such as a nozzle, cooling it, and winding it up. The diameter of the pore can be appropriately selected according to the diameter of the filament and the winding speed, but from the viewpoint of manufacturing efficiency and reducing the frequency of thread breakage defects, it is preferably 0.3 to 10.0 mm, more preferably 0.8 to 5.0 mm, and most preferably 1.0 to 3.0 mm. As for the cooling method, known methods such as air cooling and water cooling can be appropriately selected, but from the viewpoint of preventing water absorption (especially water absorption due to the hydrophilicity of cellulose fibers when using cellulose fibers), air cooling is preferred. From the viewpoint of manufacturing efficiency and reducing the frequency of thread breakage defects, the winding speed of the filament is preferably 0.1 to 10 m / sec, more preferably 0.15 to 5 m / sec, and most preferably 0.2 to 1 m / sec. The manufacturing apparatus for the filamentous material and the manufacturing apparatus for the thermoplastic elastomer resin composition may be the same or different.

[0170] Pellet-shaped materials can take various shapes, including round, elliptical, and cylindrical, and the shape may vary depending on the cutting method used during extrusion. For example, pellets cut using a method called underwater cutting are often round, pellets cut using a method called hot cutting are often round or elliptical, and pellets cut using a method called strand cutting are often cylindrical. The preferred diameter for round pellets is 1 mm to 3 mm. The preferred diameter for cylindrical pellets is 1 mm to 3 mm, the preferred length is 1 mm to 10 mm, and the more preferred length is 2 mm to 5 mm. From the viewpoint of operational stability during molding, it is desirable that the diameter and length be above the lower limit, and from the viewpoint of proper engagement with the molding apparatus during molding, it is desirable that they be below the upper limit.

[0171] The particle size, particle shape, and aspect ratio of the powdered material can be appropriately selected according to the usage conditions of the thermoplastic elastomer resin composition (for example, the 3D printer used). In one embodiment, the particle size (specifically the major axis) is preferably 1 to 1000 μm, more preferably 10 to 500 μm, and most preferably 30 to 200 μm, from the viewpoint of handling as a molding material and surface smoothness of the molded object. The particle shape may be spherical or irregular, but an irregular shape is preferred from the viewpoint of suppressing voids during molding. The aspect ratio is preferably 1.001 to 3.0, more preferably 1.01 to 2.0, and most preferably 1.1 to 1.8, from the viewpoint of suppressing voids by reducing interparticle gaps. The particle size and aspect ratio can be measured using a Morphology 4 manufactured by Malvern Panalogical.

[0172] In one embodiment, the powdered material can be produced by grinding or reprecipitating a thermoplastic elastomer resin composition. The method of grinding the thermoplastic elastomer resin composition is not particularly limited, but may include wet grinding, dry grinding, low-temperature grinding, freeze grinding, and heat grinding. A grinding medium (e.g., stainless steel balls, ceramic balls, plastic balls, glass beads, gravel) may be used to control the shape of the powdered material.

[0173] <Manufacturing of Thermoplastic Elastomer Resin Composition> A thermoplastic elastomer resin composition may be manufactured by heating and kneading a mixture containing thermoplastic elastomer raw materials and optionally other components such as cellulose fibers. The raw materials for the thermoplastic elastomer resin composition can be provided in various shapes. Specifically, these include resin pellets, sheets, fibers, plates, rods, etc. However, when the shape of the thermoplastic elastomer resin composition is a filament, the resin pellet shape is preferred due to the ease of post-processing and transportation. Preferred resin pellet shapes include round, elliptical, and cylindrical shapes, and the shape may vary depending on the cutting method used during extrusion. For example, pellets cut using a method called underwater cutting are often round, pellets cut using a method called hot cutting are often round or elliptical, and pellets cut using a method called strand cutting are often cylindrical. The preferred pellet diameter for round pellets is 1 mm to 3 mm. The preferred diameter for cylindrical pellets is 1 mm to 3 mm, and the preferred length is 2 mm to 10 mm. The diameter and length mentioned above should preferably be above the lower limit from the viewpoint of operational stability during extrusion, and below the upper limit from the viewpoint of ease of engagement with the molding machine during post-processing.

[0174] Known methods can be used to mold the raw materials of a thermoplastic elastomer resin composition into a filament, powder, or other thermoplastic elastomer resin composition. The filamentous molding material may be monofilament or multifilament, but monofilament is preferred due to its ease of molding.

[0175] <<Formed Products>> One aspect of the present invention also provides formed products obtained using the thermoplastic elastomer resin composition of the present disclosure. In one aspect, the formed product is an additive product of the thermoplastic elastomer resin composition. In one aspect, a three-dimensional object, the formed product, can be manufactured by processing (specifically forming) the thermoplastic elastomer resin composition using an additive manufacturing apparatus, such as a 3D printer. For example, the thermoplastic elastomer resin composition may be supplied to a 3D printer as a filament-like 3D printing material, and the molten 3D printing material may be extruded from the nozzle of the 3D printer.

[0176] In one embodiment, the amount of warpage of a molded object obtained using a thermoplastic elastomer resin composition is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.5 mm or less, from the viewpoint of improving dimensional accuracy, assembly with other materials, surface properties, physical properties, and moldability. The amount of warpage of the molded object is measured as the amount of lift at the other end in the long side direction when a 200 mm × 10 mm × 2 mm test piece is cut from the molded object and 10 mm is pressed down from one end in the long side direction. In one embodiment, the amount of warpage measured by the above method for a test piece made by molding a thermoplastic elastomer resin composition to a length of 200 mm × width of 10 mm × thickness of 2 mm using the procedure described in the [Examples] section may be within the above range.

[0177] In one embodiment, the surface roughness ratio of a molded object obtained using a thermoplastic elastomer resin composition is preferably 1.25 to 2.25, more preferably 1.5 to 2.0, and even more preferably 1.7 to 1.8, from the viewpoint of improving assembly with other materials, improving sliding properties, ease of post-processing, and the physical properties of the molded object. If the surface roughness ratio of the molded object is excessively high, large bumps or bulges may be observed on the surface of the molded object. If the surface roughness ratio of the molded object is excessively low, large gaps may be observed between the molded pass lines on the surface of the molded object.

[0178] The surface roughness of the molded object can be adjusted, for example, by appropriately setting the water absorption rate and porosity of the thermoplastic elastomer resin composition, and the fiber length and fiber diameter of the cellulose fibers contained in the thermoplastic elastomer resin composition.

[0179] The surface roughness ratio in this disclosure is the numerical average of 10 points obtained by measuring 10 times with an evaluation length of 4 mm in accordance with JIS B0601:2013, and dividing the number of peaks in which R was less than -10 by 4. In one embodiment, the surface roughness ratio measured by the above method on a test piece formed by molding a thermoplastic elastomer resin composition to a length of 200 mm × width of 10 mm × thickness of 2 mm in the procedure described in the [Examples] section may be within the above range.

[0180] In one embodiment, the shrinkage rate of a molded object obtained using a thermoplastic elastomer resin composition is preferably 20% or less, 15% or less, or 10% or less, and more preferably 5% or less, from the viewpoint of improving dimensional accuracy, assembly with other materials, and productivity. The shrinkage rate of the molded object can be adjusted by appropriately setting the type of thermoplastic elastomer, the amount and length of cellulose fibers, and the type and amount of dispersant contained in the thermoplastic elastomer resin composition. In one embodiment, for a test piece molded using the thermoplastic elastomer resin composition in the procedure described in the [Examples] section to form a frame shape of 200 mm in length x 200 mm in width x 20 mm in height and 1 mm in wall thickness, the shrinkage rate obtained using the following formula with respect to the length L (mm) of the obtained test piece may be within the above range. (Shrinkage rate) = (1 - L / 200) × 100

[0181] (Exposure of the infill portion of the molded object) In one embodiment, a molded object obtained using the thermoplastic elastomer resin composition of this embodiment has a surface portion and an infill portion. From the viewpoint of design, it is preferable that the infill portion is exposed at one or more locations on the molded object. It is preferable that the exposed portion accounts for 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 50% or more, 70% or more, or 90% or more of the total surface area of ​​the molded object.

[0182] In this disclosure, the term "infill portion" refers to a portion located inside the surface layer of an object formed by additive manufacturing, which is partially or entirely filled with a thermoplastic elastomer resin composition. In one embodiment, the infill portion has a pattern structure formed by the thermoplastic elastomer resin composition. Examples of infill portion patterns include gyroidal, lattice, triangular, hexagonal (honeycomb), wavy, and zigzag patterns.

[0183] In this embodiment, the filling rate of the infill portion can be arbitrarily changed between 0 and 100%. In this disclosure, the filling rate of the infill portion means the volume occupied by the thermoplastic elastomer resin composition out of the total volume of the infill portion. From the viewpoint of imparting flexibility to the molded object, the filling rate of the infill portion is preferably 99% or less, more preferably 80% or less, or 60% or less, preferably 50% or less, or 40% or less, or 30% or less, or 20% or less, or 10% or less, and from the viewpoint of the shape stability of the molded object, it is preferably 5% or more.

[0184] (Shore A hardness of the molded object) In one embodiment, the minimum Shore A hardness of the molded object obtained using the thermoplastic elastomer resin composition of this embodiment is preferably 80 A or less, more preferably 70 A or less, or 60 A or less, even more preferably 50 A or less, 40 A or less, and still more preferably 30 A or less. In one embodiment, the minimum Shore A hardness of the molded object may be 5 A or more. In the molded object, the area where the Shore A hardness is minimum is the surface area of ​​the molded object, which is 10 mm². 2 This can be defined as the location that showed the minimum value when measuring the Shore hardness for each step. Similarly, in a printed object, the location where the Shore A hardness is at its maximum value is the area of ​​the surface of the object, which is 10 mm². 2 This can be defined as the location that showed the highest value when the Shore hardness was measured for each section.

[0185] (Shore A hardness ratio of the molded object) In one embodiment, the Shore A hardness ratio of a molded object obtained using the thermoplastic elastomer resin composition of this embodiment is preferably 65% ​​or less, as determined by the following formula: (Shore A hardness ratio) = (Minimum Shore A hardness of the molded object) / (Maximum Shore A hardness of the molded object) × 100 The above Shore A hardness ratio is preferably 60% or less, more preferably 55% or less, or 50% or less, or 45% or less, or 40% or less, more preferably 35% or less, or 30% or less, and even more preferably 20% or less. In molded objects with a Shore A hardness ratio within this range, multiple parts can be molded integrally. Examples of multiple parts include the sole and upper band of a sandal. Such integral molding offers excellent productivity and design flexibility. When a molded object has a Shore A hardness ratio within the above range, the moldability of the thermoplastic elastomer resin composition and the flexibility of the molded object are excellent, the difference in hardness within the molded object can be large, and the weight of the molded object can be reduced. A lower Shore A hardness ratio is advantageous, but from the viewpoint of the mechanical strength of the molded object, in one embodiment it may be 0.1% or more, or 1% or more, or 3% or more, or 5% or more. The Shore A hardness ratio of the molded object can be adjusted by appropriately setting the balance between the Shore A hardness and elastic modulus of the thermoplastic elastomer, and appropriately setting the type and amount of additives such as cellulose fibers.

[0186] (Young's modulus) In one embodiment, the Young's modulus of the molded object may be 1 MPa or more, 5 MPa or more, or 10 MPa or more, and in one embodiment, it may be 40 MPa or less, 30 MPa or less, or 20 MPa or less. The Young's modulus of the molded object may be equal to or lower than the Young's modulus of the molding material (e.g., filament, pellets), which is a thermoplastic elastomer resin composition used in the manufacture of the molded object.

[0187] In one embodiment of the method for manufacturing a molded object, a filament is melted in a heating section of an additive manufacturing apparatus (e.g., a 3D printer), and the molten fluid is discharged from the discharge port of the heating section. The ratio F / N of the buckling load F of the filament to the pressure loss load N applied to the filament due to the pressure loss of the fluid in the heating section is 1 to 20. In this embodiment, the Young's modulus of the filament is 50 MPa or less.

[0188] For the manufacture of high-quality molded objects, it is preferable that the molding material passes smoothly through the heating section and is stably supplied to the discharge port before, during, and after melting. In particular, when the molding material is a filament, it is desirable that the filament conveyed from the extrusion mechanism (e.g., gears) of the additive manufacturing apparatus toward the heating section be smoothly supplied into the heating section from the material inlet of the heating section. In one embodiment, the relationship between the buckling load F of the filament (hereinafter also simply referred to as buckling load F) and the pressure loss-derived load N (hereinafter also simply referred to as pressure loss-derived load N) applied to the filament due to the pressure loss of the fluid in the heating section may be controlled. In a typical embodiment, the heating section of the additive manufacturing apparatus comprises a material holding section that receives and heats the molding material conveyed from the extrusion mechanism, and a discharge section (having a discharge port) that extends continuously from the material holding section for discharging the molding material. In one embodiment, the material holding section is tubular with a substantially constant inner diameter, and in one embodiment, the discharge section has a shape in which the inner diameter gradually decreases from the material holding section side toward the discharge port side. When the printing material is a soft filament (more specifically, one with a low Shore A hardness), the entire amount of filament transported from the extrusion mechanism to the heating section cannot be introduced into the heating section, making it prone to bending (i.e., buckling) between the extrusion mechanism and the heating section. When buckling occurs, the fluid is not supplied to the discharge port as set, which can degrade the quality of the printed object. In particular, if buckling occurs in a gap between the extrusion mechanism and the heating section, causing the filament to protrude into the gap, additional operations such as interrupting filament transport and cleaning the equipment may be required to resolve the issue. Therefore, it is preferable to evaluate the buckling load of the filament and control the printing material and printing conditions so that the buckling load does not fall below the load on the filament due to pressure loss during additive manufacturing.

[0189] Factors contributing to pressure loss in additive manufacturing equipment include friction between the inner walls of the material holding section (typically tubular) and the discharge section (typically involving a gradual decrease in inner diameter from the material holding section to the discharge port) and the fabricated material (hereinafter referred to as internal pipe friction), and the aforementioned change in inner diameter in the discharge section (hereinafter referred to as diameter change). To reduce buckling, it is useful for the filament to exhibit physical properties that can withstand the load resulting from the pressure loss. According to the inventors' studies, the pressure loss due to the diameter change is minor, so particular attention should be paid to the pressure loss due to internal pipe friction. Therefore, in one embodiment, the pressure loss due to internal pipe friction is considered among the internal pipe friction and diameter change described above.

[0190] The buckling load F is a value indicating the extent to which a filament can withstand a load in the longitudinal direction (opposite to the filament transport direction) without buckling. The pressure loss load N is a value indicating the extent to which a load in the opposite direction to the filament transport direction is applied to the filament during additive manufacturing. If the ratio of buckling load F to pressure loss load N is less than 1, buckling can be predicted to occur, and if the ratio is 1 or greater, buckling can be predicted not to occur. From the viewpoint of obtaining a good buckling reduction effect, the above ratio is, in one embodiment, 1 or more, or 1.5 or more, or 2 or more, and from the viewpoint of ease of manufacturing the filament and flexibility of the molded product, in one embodiment, 20 or less, or 10 or less, or 5 or less. The calculation procedure for the buckling load F and pressure loss load N in this disclosure will be further explained below.

[0191] The buckling load F (in Newtons) is, in one aspect, expressed by the following equation (I): F = n × π 2 ×E×I / R 2 (I) n: coefficient E: Young's modulus of the filament (MPa) I: second moment of area of ​​the filament (mm 4) R: Distance from the extrusion mechanism to the material inlet (mm) n is a value determined by whether or not both ends of the filament are fixed. During filament transport, one end of the filament is fixed and the other end is not, so n is 1 / 4. If both ends of the filament are rotatable, n is 1, and if both ends are fixed, n is 4. I is I = π × (filament diameter (mm)) 4 It is calculated by ( / 64). In this disclosure, the filament diameter means the maximum cross-section of the filament in the radial direction, and more specifically, the average value d2 described below.

[0192] The pressure loss-derived load N (unit: N) is, in one embodiment, expressed by the following formula (II): N = {(8π × μ1 × L1 × v1) + (8π × μ2 × L2 × v2)} × 10 -6 (II) μ1: Shear viscosity of the material holding section of the 3D printer (Pa·s) μ2: Shear viscosity of the material dispensing section of the 3D printer (Pa·s) L1: Length of the material holding section (mm) L2: Length of the dispensing section (mm) v1: Fluid velocity of the material passing through the material holding section (mm / s) v2: Fluid velocity of the material passing through the dispensing section (mm / s)

[0193] Equation (II) above is derived more specifically according to the following steps 1 to 7: 1. Derivation of the shear viscosity of the molding material 2. Confirmation that it is a laminar flow 3. Calculation of the friction coefficient of the material holding section 4. Calculation of the pressure drop of the material holding section 5. Calculation of the load due to the pressure drop of the material holding section 6. Calculation of the load due to the pressure drop of the discharge section 7. Calculation of the load due to the pressure drop of both the material holding section and the discharge section as the pressure drop-derived load N The following explains this in detail.

[0194] 1. Derivation of shear viscosity of the molding material. Shear rate γ(s) during additive manufacturing of the molding material, which is a molten filament. -1 The shear rate γ and the shear viscosity μ1 at the assumed molding temperature are calculated according to the following formula (1), and the shear rate γ and the shear viscosity μ1 at the assumed molding temperature are determined by actual measurement. γ = 4 × (πd 2 / 4)×(S / 60)×(8 / (πD1 3)) (1) d: filament diameter (mm) S: filament feed rate by extrusion mechanism (mm / min) D1: inner diameter of material holding part (mm) A known rheometer (for example, TA Instruments, model number ARES-G2) can be used to measure the shear viscosity μ1. In one embodiment, the assumed molding temperature is the highest temperature among the values ​​shown by the thermoplastic polymer in the molding material, which is 50°C higher than the melting point of the thermoplastic polymer (for polymers having a melting point) and / or 340°C higher than the glass transition point of the thermoplastic polymer (for polymers having a glass transition point).

[0195] 2. Confirmation of laminar flow Based on the shear viscosity μ1 obtained in 1. above, the flow of the molding material during additive manufacturing is confirmed to be laminar by the Reynolds number Re according to the following equation (2): Re = (ρv1D1) / μ (2) ρ: density of the molding material (g / cm³) 3 ) v1: Fluid velocity of the material being molded passing through the material holder (mm / s) D1: Inner diameter of the material holder (mm) μ1: Shear viscosity of the material being molded in the material holder (Pa·s) Based on the Reynolds number Re, the following criteria are used to determine whether it is laminar flow or not: Re ≤ 2100 Laminar flow 2100 < Re ≤ 4000 Laminar flow + turbulent flow 4000 < Re Turbulent flow

[0196] If the Reynolds number Re is calculated to be greater than 2100 using the above procedure, it is determined that the flow is not laminar. In this case, the conditions are changed so that one or more of the elements of equation (1) and / or (2) are changed so that the Reynolds number Re becomes 2100 or less, and the above determination is performed again. This operation is repeated until the Reynolds number Re becomes 2100 or less. The condition changes may be one or more of the following, for example, changing the filament feed rate, changing the fluid velocity of the molding material passing through the material holding section, or changing the shear viscosity by adjusting the molding temperature.

[0197] 3. Calculation of the friction coefficient of the material holding part Based on the Reynolds number Re obtained in 2. above, the friction coefficient λ1 of the material holding part is calculated according to the following formula (3). As mentioned above, the Reynolds number Re is set to 2100 or less. λ1 = 64 / Re (3)

[0198] 4. Calculation of pressure loss in the material holding section Based on the friction coefficient λ1 of the material holding section obtained in 3. above, the pressure loss Δh1 (N / mm) of the material holding section is calculated according to the following formula (4). 2 Calculate Δh1 = λ1 × (L1 / D1) × (ρv1 2 / 2) (4) λ1: Coefficient of friction of the material holding part L1: Length of the material holding part (mm) D1: Inner diameter of the material holding part (mm) ρ: Density of the molding material (g / cm³) 3 ) v1: Fluid velocity of the molding material passing through the material holding section (mm / s)

[0199] 5. Calculation of load due to pressure loss in the material holding section Based on the pressure loss Δh1 obtained in 4. above, the load N1 (N) due to the pressure loss in the material holding section is calculated according to the following formula (5). N1 = Δh1 × A1 (5) Δh1: pressure loss (N / mm 2 ) A1: Cross-sectional area of ​​the material holding part (mm 2 ) (=π × (D1 / 2) 2 )

[0200] 6. Calculation of the load due to pressure loss at the discharge section The load N2 (N) due to pressure loss at the discharge section is calculated using the same procedure as in 1 to 5 above, except that "material holding section" is replaced with "discharge section" (for example, "length of material holding section" is replaced with "length of discharge section"). For convenience, the arithmetic mean of the inner diameter of the boundary between the material holding section and the discharge section and the inner diameter of the discharge port is treated as the inner diameter of the discharge section.

[0201] 7. The load originating from the pressure loss in both the material holding section and the discharge section is calculated as the pressure loss-derived load N. The load N1 calculated in 5. above and the load N2 calculated in 6. above are added together to obtain the pressure loss-derived load N, which is the load originating from the pressure loss in both the material holding section and the discharge section.

[0202] Combining steps 1 through 7 above, we derive equation (II) above.

[0203] The ratio of buckling load F to pressure loss-derived load N can, in one embodiment, be controlled by adjusting the elements in each of the aforementioned equations. The elements that can be adjusted include the following: Molding material: coefficient (material type), density, viscosity, Young's modulus, filament diameter Additive manufacturing apparatus: distance from the extrusion mechanism to the material inlet, fluid velocity of the molding material passing through the material holding section and / or discharge section, inner diameter of the material holding section and / or discharge section, length of the material holding section and / or discharge section, friction coefficient of the material holding section and / or discharge section By controlling the ratio of buckling load F to pressure loss-derived load N, a stable supply of molding material to the additive manufacturing apparatus is possible, even when using soft molding material.

[0204] ≪Applications of Thermoplastic Elastomer Resin Composition and Molded Products≫ The thermoplastic elastomer resin composition of this embodiment and molded products obtained using the thermoplastic elastomer resin composition can be suitably used for: space equipment such as rockets and artificial satellites; aircraft; drones; wearable components and devices such as orthotics, assist suits, VR goggles, wearable devices, pads, headphones, earphones, and mouthpieces; sports equipment such as soles, rackets, fishing gear, bicycles, and saddles; infrastructure such as utility poles, power lines, and underground trenches; cars; construction materials; robots and robot hands; electrical and electronic components; switches; hanging devices; various containers; daily necessities; household goods; hygiene products; tools; jigs; cases; connectors; prosthetics and orthotics; shoe components such as shoe bodies, insoles, and outsoles; housings for prosthetics and orthotics, welfare equipment, medical equipment, analytical instruments, etc.; grips for sports equipment, game equipment, camera equipment, etc.; packing; bedding such as pillows; cushions; protective materials; shock-absorbing materials; dampers; factory equipment such as shock-absorbing materials for air conditioning outlets, bonding shock-absorbing materials, and heat-insulating protective components; multifunction printer parts; smartphone accessories, etc.

[0205] In automotive applications, it can be used in, but is not limited to, the chassis / frame, suspension, drivetrain components, interior components, exterior components, functional components, and other parts.

[0206] Specifically, steering shaft, mount, sunroof, step, soffit trim, door trim, trunk, boot lid, bonnet, seat frame, seat back, retractor, retractor support bracket, clutch, gear, pulley, cam, AG, elastic beam, baffling, lamp, reflector, glazing, front end module, back door inner, brake pedal, steering wheel, electrical materials, sound-absorbing materials, door exterior, interior panel, instrument panel, rear gate, ceiling beam, seat, seat frame, wiper support, EPS (Electric Power Steering), small motor, heat sink, ECU (Engine Control Unit) box, ECU housing, steering gearbox housing, plastic housing, EV (Electric Vehicle) Motor housing, wire harness, on-board meter, combination switch, small motor, spring, damper, wheel, wheel cover, frame, subframe, side frame, two-wheel frame, fuel tank, oil pan, intake manifold, propeller shaft, drive motor, monocoque, hydrogen tank, fuel cell electrodes,

[0207] Panels, floor panels, exterior panels, doors, cabin, roof, hood, valves, EGR (Exhaust Gas) Recirculation valves, variable valve timing unit, connecting rods, cylinder bores, members (engine mounting, front floor cloth, footwell cloth, seat cloth, inner side, rear cloth, suspension, pillar reinforcement, front side, front panel, upper, dash panel cloth, steering), tunnel, fastening inserts, crash boxes, crash rails, corrugated, roof rails, upper body, side rails, braiding, door surround assembly, airbag components, body pillars, dash-to-pillar gussets, suspension towers, bumpers, lower body pillars, front body pillars, reinforcements (instrument panel, rails, roof, front body pillars, roof rails, roof side rails, rockers, door beltlines, front floor under, upper front body pillars, lower front body pillars, center pillars, center pillar hinges, door outside panels), side outer panels, front door window frames,

[0208] MICS (Minimum Intrusion Cabin System) bulkhead, torque box, radiator support, radiator fan, water pump, fuel pump, electronic throttle body, engine control ECU, starter, alternator, manifold, transmission, clutch, dash panel, dash panel insulator pad, door side impact protection beam, bumper beam, door beam, bulkhead, outer pad, inner pad, rear seat rod, door panel, door trim body sub-assembly, energy absorber (bumper, impact absorber), impact absorber, impact absorbing garnish, pillar garnish, roof side inner garnish, resin rib, side rail front spacer, side rail rear spacer, seat belt pretensioner, airbag sensor It can be suitably used as a component such as arms (suspension, lower, hood hinge), armrests, suspension links, impact absorption brackets, fender brackets, inverter brackets, inverter modules, hood inner panels, hood panels, cowl louvers, cowl top outer front panels, cowl top outer panels, floor silencers, dump sheets, hood insulators, fender side panel protectors, cowl insulators, cowl top ventilator louvers, cylinder head covers, tire deflectors, fender supports, strut tower bars, transmission center tunnels, floor tunnels, radiator core supports, luggage panels, luggage floors, accelerator pedals, accelerator pedal bases, etc.

[0209] Examples of space equipment include rockets and satellites, as well as space environment sensors and their housings, spacecraft attitude control systems, spacecraft communication equipment, rovers, space telescopes, experimental equipment for the space environment, and space debris tracking devices.

[0210] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples and can be implemented with various modifications within the scope of the gist of the present invention.

[0211] The following measurements and evaluations were performed on the thermoplastic elastomer resin compositions obtained in each example, the fabrication processes using the thermoplastic elastomer resin compositions, and the fabricated objects obtained through these processes.

[0212] ≪Evaluation Method≫ <Thermoplastic Elastomer> [MFR at 230°C, 2.16 kg] The value from the product catalog is shown.

[0213] [Hardness] Two test specimens (ISO 37 type 3) made using a dedicated desktop injection molding machine (DSM Corporation) at a mold temperature of 80°C were stacked to create a specimen with a thickness of 8 mm. The hardness of this specimen was measured in accordance with ISO 7619 using a hardness tester (DM-204A; Muratec KDS Corporation).

[0214] <Cellulose Fibers> [Average Fiber Length of CNF-A] The concentrated cake was diluted with tert-butanol to 0.01% by mass, dispersed using a high-shear homogenizer (IKA, product name "Ultra-Turrax T18") under the following conditions: rotation speed 15,000 rpm x 3 minutes, cast onto an osmium-deposited silicon substrate, air-dried, and measured with a high-resolution scanning electron microscope (Hitachi High-Tech Corporation, Regulus 8220). The measurement was performed by adjusting the magnification so that at least 100 cellulose fibers could be observed, the major axis of 100 randomly selected cellulose fibers was measured, and the average length of the 100 cellulose fibers was calculated.

[0215] <Cellulose Fibers Contained in Thermoplastic Elastomer Resin Composition> [10% Average Fiber Length] The thermoplastic elastomer of the thermoplastic elastomer resin composition was dissolved in a solvent (toluene if the thermoplastic elastomer is a styrene-based elastomer or TPE, acetone if it is a polyurethane-based elastomer, and hexafluoro-2-propanol (HFIP) if the resin is a polyamide) to a concentration of 0.5 mg / mL of cellulose fibers. The resulting CNF dispersion solution was treated in an ultrasonic cleaner for 1 hour, and 1.7 μL of it was dropped onto a slide. A glass cover was placed over the slide, and it was observed at 20x magnification using a microscope (digital microscope VHX-5000, manufactured by Keyence Corporation). The obtained images were processed using ImageJ according to the following procedure, and the average fiber length of the fibers that were in the top 10% of the obtained fibers was taken as the 10% average fiber length of the cellulose fibers contained in the thermoplastic elastomer resin composition. Although the fiber length measured using this method is limited to fibers with a diameter of 1 μm or more due to the limitations of microscope measurement, fibers with a diameter of less than 1 μm can be considered to have substantially similar fiber lengths. Therefore, the fiber lengths obtained using this method were treated as the fiber lengths of cellulose fibers.

[0216] (Processing with ImageJ) The following processing was performed using ImageJ: 1. After loading the image, convert it to 8-bit (Image > Type > 8bit) 2. Filtering (Plugins > Bilateral Filter > Bilateral Fiji; spatial radius: 1, range radius: 10) 3. Background removal (Process > Subtract Background; Rolling ball radius: 10 pixels) 4. Binarization (Image > Adjust > Threhold (Triangle)) 5. 1. Noise Reduction (Analyze > Analyze particles; Size: 15-Infinity, Circularity: 0.00-0.40) 6. Thinning (Process > Binary > Skeltonize) 7. Fiber Length Evaluation (Plugins > RidgeDetection; Line width: 25, High Contrast: 230, Low Contrast: 87, Sigma: 7.72, Lower Trehold: 0.00, Upper Trehold: 0.17, Minimum Line Length: 20, Maximum Line Length: 0.00)

[0217] [Number-average fiber diameter] A concentrated cellulose fiber cake was diluted to 0.01% by mass with tert-butanol, dispersed using a high-shear homogenizer (IKA, product name "Ultra-Turrax T18") under the following conditions: rotation speed 15,000 rpm for 3 minutes, cast onto an osmium-deposited silicon substrate, and air-dried. The sample was then measured using a high-resolution scanning electron microscope (Hitachi High-Tech Corporation, Regulus 8220). The measurement was performed by adjusting the magnification so that at least 100 cellulose fibers could be observed. The diameter (D) of 100 randomly selected cellulose fibers was measured, and the number-average fiber diameter was calculated by adding up the diameters of the 100 cellulose fibers.

[0218] [Thermal decomposition start temperature (T D)) (Production of porous sheet) First, the concentrated cake was added to tert-butanol, and further dispersed with a mixer or the like until there were no aggregates. It was adjusted so that the concentration would be 0.5 mass% with respect to 0.5 g of the cellulose fiber solid content weight. 100 g of the obtained tert-butanol dispersion was filtered on filter paper. The filtrate was sandwiched between two larger filter papers without peeling it from the filter paper, and while pressing the edges of the larger filter paper with weights, it was dried in an oven at 150 °C for 5 minutes. Then, the filter paper was peeled off to obtain a porous sheet with little distortion. The porous sheet having an air permeability resistance of 100 sec / 100 ml or less per 10 g / m 2 was used as the porous sheet and used as the measurement sample. After measuring the basis weight W (g / m 2 ) of the sample left standing for 1 day in an environment of 23 °C and 50% RH, the air permeability resistance R (sec / 100 ml) was measured using a Wang Research type air permeability resistance tester (manufactured by Asahi Seiko Co., Ltd., model EG01). At this time, according to the following formula, the value per 10 g / m 2 basis weight was calculated. Air permeability resistance per 10 g / m 2 (sec / 100 ml) = R / W × 10

[0219] (Thermal analysis) The thermal analysis of the porous sheet was performed by the following measurement method. Apparatus: Thermo plus EVO2 manufactured by Rigaku Corporation Sample: A circularly cut-out piece from the porous sheet was placed in an aluminum sample pan in a stack of 10 mg. Sample amount: 10 mg Measurement conditions: In a nitrogen flow of 100 ml / min, the temperature was raised from room temperature to 150 °C at a heating rate of 10 °C / min, held at 150 °C for 1 hour, and then the temperature was raised to 450 °C as it was at a heating rate of 10 °C / min. T D Calculation method: Obtained from a graph with the temperature on the horizontal axis and the weight residual rate % on the vertical axis. Starting from the weight (weight reduction amount 0 wt%) of the porous sheet at 150 °C (state where moisture was almost removed), heating was continued, and a straight line passing through the temperature at 1 wt% weight reduction and the temperature at 2 wt% weight reduction was obtained. The temperature of the point where this straight line intersects the horizontal line (baseline) passing through the starting point of 0 wt% weight reduction was taken as the thermal decomposition start temperature (T D ).

[0220] <Thermoplastic Elastomer Resin Composition> The following measurements were performed on filaments or pellets of thermoplastic elastomer resin composition. For filaments, granular material obtained by cutting the filament to a length of 3 mm with wire cutters was used as a sample.

[0221] [Young's Modulus] Multipurpose test specimens conforming to ISO 294-3 were obtained by molding at a mold temperature of 80°C using a dedicated desktop injection molding machine (manufactured by DSM). The Young's modulus of the test specimens was measured in accordance with ISO 527-1 and calculated within the strain range of 0.25 to 0.5%. Granular material was sampled at 10 locations every 500 mm over a length of 15 mm (per location) of the filament. The minimum value among the measurement results at the 10 locations was taken as the Young's modulus.

[0222] [Shore A Hardness] Four test specimens (ISO 37 type 3) made using a dedicated desktop injection molding machine (DSM Corporation) at a mold temperature of 80°C were stacked to create a test specimen with a thickness of 8 mm. The hardness of this specimen was measured in accordance with ISO 7619 using a hardness tester (DM-204A; Muratec KDS Corporation).

[0223] [Flexibility Index] Using a 3D printer (Raise3D pro3, manufactured by Raise3D), an object with a dome-shaped outer wall measuring 63 mm wide x 82 mm deep x 15 mm high, a gyroid shape with a 10% infill rate, two bottom layers in the 45° and 135° directions, and eight concentric solid layers was fabricated under the conditions described in each example, with an ambient temperature of 23°C, a nozzle diameter of 0.8 mm, and nozzle and bed temperatures. The flexibility index was calculated by dividing the hardness of the upper center of the dome shape of the fabricated object by the hardness of the thermoplastic elastomer resin composition of each example. Hardness was measured in accordance with ISO 7619 using a hardness tester (DM-204A; manufactured by Muratec KDS Co., Ltd.).

[0224] [Printing Pitch Coefficient] Using a 3D printer (Raise3D pro3, manufactured by Raise3D), strip-shaped test specimens with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm were fabricated under the conditions described in each example: ambient temperature of 23°C, nozzle diameter of 0.8 mm, nozzle temperature, and bed temperature. The layering pitch direction was the thickness direction of the strip-shaped test specimen. The top and bottom surfaces of the strip-shaped test specimen were 80 mm long × 10 mm wide. The entire outer circumference was laminated in the thickness direction of the strip-shaped test specimen while moving the nozzle so that the direction along the outer circumference of 80 mm long × 10 mm wide was the longitudinal direction of each layer. The first two layers from the top and the first two layers from the bottom were laminated at 45° and 135° angles to the longitudinal direction of the test specimen, respectively, while the remaining layers were laminated parallel to the longitudinal direction of the test specimen (i.e., the width direction of the test specimen corresponded to the longitudinal direction of each layer). The objects were fabricated with layer thicknesses of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm. Fabrication was considered successful if the resulting object had a length of 70-90 mm, a width of 9-11 mm (i.e., within ±10% of the design dimension in the width direction), and a thickness of 3.6-4.4 mm (i.e., within ±10% of the design dimension in the thickness direction). If it was outside this range, it was considered a failure. The fabrication pitch coefficient was calculated by dividing the maximum layer thickness at which fabrication was successful by the nozzle diameter of 0.8 mm.

[0225] [Modulus of elasticity at 10% elongation] A dumbbell-shaped test specimen (No. 3) of JIS K6251 was prepared using an injection molding machine (EC5P, manufactured by Shibaura Machine Co., Ltd.), and a tensile test was performed with an air chuck pressure of 0.25 MPa and a tensile speed of 50 mm / min. The stress when the gauge length was elongated by 10% was multiplied by 10 to determine the modulus of elasticity at 10% elongation of the thermoplastic elastomer resin composition.

[0226] [Viscosity of thermoplastic polymers at 280°C] Viscosity was measured using a benchtop melt indexer (L260, Tateyama Chemical High Technologies Co., Ltd.) in accordance with ISO 1133, under conditions of 280°C and a load of 2.16 kg.

[0227] [Water Absorption Rate] Using the thermoplastic elastomer resin compositions produced in the examples and comparative examples described later, the moisture content (ppm) in the pellets was measured using a Karl Fischer moisture meter (Coleometric titration type trace moisture analyzer CA-200, manufactured by Mitsubishi Chemical Analytec Co., Ltd.) in accordance with ISO 15512.

[0228] [Porrosion] The porosity of the thermoplastic elastomer resin composition was calculated by cutting the thermoplastic elastomer resin composition using a microtome, observing the cross-section with a scanning electron microscope (SEM), and determining the ratio of the area occupied by voids to the cross-sectional area of ​​the thermoplastic elastomer resin composition from the obtained image. The area occupied by voids was determined using ImageJ by the following procedure: 1. Select a range along the outer shape of the filament or pellet, and use Analyze → Measure to obtain the area of ​​the cross-section of the filament or pellet. 2. Use Edit → Clear Outside to erase parts other than the cross-section of the filament or pellet. 3. Use Image → Adjust → Color Balance to adjust the hue. 1. Move the Brightness bar all the way to the right, and move the Maximum bar to the left of the tail of the histogram peak, so that it is exactly at the tail of the Minimum histogram peak. 4. In Image → Color → Split Channels, separate into three RGB colors and close all windows except Red. 5. In Process → Binary → Make Binary, define it as black and white. 6. In Analyze Particles, find the area of ​​the black dots as the area of ​​the voids. 7. Divide the area of ​​the voids found in step 6 by the area of ​​the filament or pellet cross-section found in step 1 to find the void ratio.

[0229] [Average value and variation of filament diameter] The wire diameter was measured by passing 10 m of filament wound on a spool through a wire diameter measuring instrument (LS-9006MR, LS-9006MT, KEYENCE Co., Ltd.) at a speed of 1 m / min. The sampling interval was 5 points / second. The maximum, minimum, and average values ​​of the obtained wire diameters were calculated. The variation of the filament diameter was calculated by subtracting the average value D2 from the minimum value D1, dividing the result by the average value D2, and multiplying by 100 ((D1-D2) / D2×100), and then subtracting the average value D2 from the maximum value D3, dividing the result by the average value D2, and multiplying by 100 ((D3-D2) / D2×100).

[0230] [Amount of Aggregates] The amount of aggregates in the thermoplastic elastomer resin composition was evaluated by holding the thermoplastic elastomer resin composition up to the light and counting the number of aggregates with a diameter of 0.3 mm or more that could be visually confirmed. Whether or not an aggregate had a diameter of 0.3 mm or more was determined by measuring it with a ruler.

[0231] [Melt Mass Flow Rate (MFR)] The MFR of the thermoplastic elastomer resin composition of each example was measured in accordance with ISO 1133, by applying a load of 2.16 kg at the same nozzle temperature as described in each example.

[0232] <Formability during fabrication> [Adhesion to build plate] Using the thermoplastic elastomer resin compositions prepared in each example, a rectangular prism with a length of 50 mm, a width of 50 mm, and a height of 5 mm was fabricated using a 3D printer. If no peeling from the build plate was observed during fabrication, it was evaluated as "good" indicating excellent adhesion to the build plate; if peeling was observed, it was evaluated as "poor".

[0233] [Holes in the fabricated object] Using the thermoplastic elastomer resin compositions prepared in each example, cylindrical objects with a diameter of 20 mm and a height of 150 mm were fabricated using a 3D printer. The number of holes formed on the side surface of the fabricated object was counted, and it was evaluated that the fewer the holes, the better the fabrication performance.

[0234] [Printing Stability] Using the thermoplastic elastomer resin compositions prepared in each example, cubes with a length of 50 mm, a width of 50 mm, and a height of 50 mm were printed using a 3D printer. The cubes consisted of a total of 250 layers. During this process, the number of times the filament or pellets clogged the nozzle was measured. A lower number of clogs indicated superior printing stability.

[0235] <Printed Object> [Printing Method] (Filament Printing Conditions) Printing was performed using a 3D printer (Raise3D pro3, manufactured by Raise3D) at an ambient temperature of 23°C, a nozzle diameter of 0.8 mm, and a layer thickness of 0.3 mm. The nozzle temperature, bed temperature, and printing speed were set to the conditions described in each example.

[0236] (Pellet Forming Conditions) Using pellets of the thermoplastic elastomer resin composition obtained in each example, 3D printing was performed using a 3D printer (EXT 1070 Titan Pellet, manufactured by 3D SYSTEMS) at an ambient temperature of 80°C, a nozzle temperature of 265°C, a bed temperature of 65°C, and a nozzle diameter of 1 mm. If specific forming conditions were designated in each evaluation, those instructions were followed.

[0237] [Young's Modulus] Using filament, a multi-purpose test specimen conforming to ISO 294-3 was fabricated as an object using a 3D printer. During fabrication, the layering direction was such that the two outermost layers were fabricated along the outer circumference, and the remaining layers were fabricated parallel to the longitudinal direction of the test specimen. Young's modulus was measured in accordance with ISO 527-1 and calculated within the strain range of 0.25 to 0.5%.

[0238] [Shrinkage Rate] A thermoplastic elastomer resin composition described in each example was fabricated using a frame shape of 200 mm in length, 200 mm in width, and 20 mm in height, with a wall thickness of 1 mm, to obtain a test specimen as a fabricated object. The layering pitch direction is the height direction. The layering direction during fabrication (i.e., the longitudinal direction of each layer) was along the outer circumference of all layers. The shrinkage rate was calculated using the following formula with the length L (mm) of the obtained test specimen: (Shrinkage Rate) = (1 - L / 200) × 100

[0239] [Tensile Elongation] A dumbbell shape, as specified in JIS K6251, was fabricated. The layering direction during fabrication was parallel to the longitudinal direction of the entire test specimen. A tensile test was performed with an air chuck pressure of 0.25 MPa, a tensile speed of 50 mm / min, and a gauge length of 20 mm. The tensile elongation of the thermoplastic elastomer resin composition was defined as the elongation between the gauges at fracture divided by the gauge length.

[0240] [Warpage Amount] Using the thermoplastic elastomer resin compositions prepared in each example, test specimens measuring 200 mm in length, 10 mm in width, and 2 mm in thickness were fabricated using a 3D printer. The layering pitch direction was the thickness direction of the strip-shaped test specimen. During fabrication, the layering direction was such that the two outermost layers were fabricated along the outer circumference, the top two layers and the bottom two layers were fabricated at 45° and 135° angles to the longitudinal direction of the test specimen, respectively, and the remaining layers were fabricated parallel to the longitudinal direction of the test specimen. Holding down 10 mm from one end in the longitudinal direction, the amount of lift at the other end in the longitudinal direction was photographed with a digital camera (Panasonic DMA-SZ10) while applying a ruler, and the amount of lift was calculated as the warpage amount by comparing it with the ruler markings in ImageJ.

[0241] [Shore A Hardness Ratio] Using the thermoplastic elastomer resin compositions prepared in each example, test specimens measuring 100 mm in length, 30 mm in width, and 20 mm in thickness were fabricated using a 3D printer. Half of the longitudinal half of the fabricated object was fabricated with a gyroid-shaped infill with a 100% filling rate, and the other half was fabricated with a gyroid-shaped infill with a 10% filling rate. No outer wall was provided. The hardness was measured in accordance with ISO 7619 using a hardness tester (DM-204A; manufactured by Muratec KDS Co., Ltd.) at two points: 25 mm from each end in the longitudinal direction toward the center in the longitudinal direction, and at the center in the width direction of the test specimen (i.e., 15 mm from the end in the width direction). (Therefore, one point was the area with 100% filling rate, and the other point was the area with 10% filling rate.) Of the two hardness values, the lower value was designated as A (corresponding to the minimum Shore A hardness of the printed object), and the higher value as B (corresponding to the maximum Shore A hardness of the printed object). The Shore A hardness ratio was then calculated using the following formula: (Shore A hardness ratio) = A / B × 100

[0242] <<Materials Used>> Next, the materials used in the examples and comparative examples are as follows.

[0243] <Fibers> (Cellulose Fibers) CNF-A: 3 parts by mass of cotton linter pulp was immersed in 27 parts by mass of water and dispersed with a pulper. 30 parts by mass of the cotton linter pulp slurry processed by the pulper (including 3 parts by mass of cotton linter pulp) was mixed with 170 parts by mass of water and dispersed in water (solid content rate: 1.5% by mass). Using an SDR14 type laboratory refiner (pressure type DISK type) manufactured by Aikawa Iron Works Co., Ltd. as a disk refiner, with the clearance between disks set to 1 mm, the aqueous dispersion was refined for 30 minutes. Subsequently, refining was thoroughly performed under conditions where the clearance was reduced to a level close to almost zero, and a refined aqueous dispersion (solid content concentration: 1.5% by mass) was obtained. The obtained refined aqueous dispersion was directly processed 10 times under an operating pressure of 100 MPa using a high-pressure homogenizer (NSO15H manufactured by Niro Soavi, Italy) to obtain a slurry (solid content concentration: 1.5% by mass). Then, it was concentrated to a solid content rate of 20% by mass using a dehydrator, and 15 parts by mass of a CNF-A concentrated cake was obtained. The average fiber length of the obtained CNF-A was 130 μm, the number average fiber diameter was 65 nm, and the thermal decomposition start temperature was 290 °C.

[0244] (Carbon Fibers) CF-A HTC413 (manufactured by Toray Tenax Co., Ltd.)

[0245] <Thermoplastic Elastomer> Thermoplastic Elastomer 1: SEBS (Tuftec H1052 manufactured by Asahi Kasei Corporation), MFR: 14 g / 10 min (230 °C, 2.16 kg), Shore A hardness: 60A, density: 0.89 g / cm 3 Thermoplastic Elastomer 2: Maleic acid-modified SEBS, Tuftec M1943 manufactured by Asahi Kasei Corporation, MFR: 6.5 g / 10 min (230 °C, 2.16 kg), Shore A hardness: 65A, density 0.91 g / cm 3 (As a value specific to SEBS, a value obtained based on the water substitution method) Thermoplastic Elastomer 3: Thermoplastic polyurethane (Estane ET680 manufactured by N-T-W Co., Ltd.), Shore A hardness: 80A, density: 1.2 g / cm 3Young's modulus: 75 MPa, viscosity at 280°C: 270 g / 10 min. Thermoplastic elastomer 4: TPE filament (TPE60A, manufactured by Hotty Polymer Co., Ltd.), Shore A hardness: 60A, density: 1.3 g / cm³. 3 Young's modulus: 70 MPa, viscosity at 280°C: 120 g / min. Thermoplastic elastomer 5: SEBS (Asahi Kasei Corporation ToughTec H1221), Shore A hardness: 36A, density: 0.89 g / cm³. 3 Thermoplastic elastomer 6: SEBS (Asahi Kasei Corporation ToughTec H1521), Shore A hardness: 39A, Density: 0.89 g / cm³ 3 Thermoplastic elastomer 7: SEBS (Asahi Kasei Corporation ToughTec S1613), Shore A hardness: 45A, Density: 0.91 g / cm³ 3 Thermoplastic elastomer 8: SEBS (Kraton G1648), Shore A hardness: 52A, Density: 0.90 g / cm³ 3

[0246] <Thermoplastic Resin> Thermoplastic Resin 1: Polyamide Filament (BASF PA-4501a075 (Natural))

[0247] <Dispersant> Polyethylene glycol: PEG6000, manufactured by Sanyo Chemical Industries, Ltd.

[0248] <Liquid Polymer> Liquid polybutadiene: RICON 184, manufactured by Clay Valley Corporation; viscosity at 25°C: 75,000 mPa·s

[0249] <Antioxidant> Antioxidant: BASF Irganox 245

[0250] <Filaments> [Examples 1-1 to 1-6, 1-8 to 1-11, 1-13] CNF concentrated cake (the mass in the table is based on solid content, the same applies hereafter), a dispersant, and a liquid polymer were mixed using a planetary mixer in the proportions shown in the table, and then dried under reduced pressure to obtain a cellulose dry product.

[0251] The above-mentioned dried cellulose, thermoplastic elastomer, and antioxidant were blended in the proportions shown in the table and kneaded in a twin-screw extruder to obtain cellulose-containing elastomer pellets.

[0252] The obtained pellets were extruded using a single-screw extruder at room temperature (23°C) and wound into filaments to obtain a thermoplastic elastomer resin composition. The filament production conditions are shown in Tables 1 and 2. In Tables 1 and 2, C1 to C4 are the zones in the extruder, and are C1, C2, C3, and C4 in order from closest to the hopper. Filaments were obtained (minimum filament diameter d1: 1.72 mm, average value d2: 1.75 mm, and maximum value d3: 1.78 mm, arithmetic mean roughness Ra: 10 μm). Using the obtained filaments, objects for evaluation were manufactured according to the procedure described in the "Evaluation Method" section. The measurement and evaluation results of the filaments and objects are shown in Tables 1 and 2. Before each molding process, the filaments were dried in a vacuum dryer at 80°C for 24 hours.

[0253] [Example 1-7] The same procedure as in Example 1-1 was followed, except that the filament was not dried before printing. The measurement and evaluation results of the filament and the printed object are shown in Tables 1 and 2.

[0254] [Example 1-12] Using the filament obtained in Example 1-10, a test piece measuring 100 mm in length, 30 mm in width, and 20 mm in thickness was fabricated using a 3D printer (Raise3D pro3, manufactured by Raise3D) under the following conditions: ambient temperature 23°C, nozzle diameter 0.8 mm, layer thickness 0.3 mm, nozzle temperature 300°C, bed temperature 60°C, and printing speed 15 mm / s. The infill of the fabricated object was set to a gyroid shape with a filling density of 10%, and the longitudinal half of the fabricated object was covered with two layers of walls, while the other half was fabricated without walls. The resulting fabricated object was as designed, with half covered by walls and the other half without walls, and had an excellent appearance.

[0255] [Example 1-13] The 3D printer used was a K1C manufactured by Crearity, and the evaluation was carried out in the same manner as in Example 1-1 using the filaments listed in Table 2.

[0256] [Comparative Examples 1-1 to 1-3] Evaluations were performed in the same manner as in Example 1-1 using the filaments described in Tables 1 and 2. The measurement and evaluation results of the filaments and printed objects are shown in Tables 1 and 2. When printing using the filament of Comparative Example 1-2, masking tape was applied to the bed before printing.

[0257] ≪Calculation of buckling load F and pressure loss-derived load N, and manufacturing of molded objects≫ The buckling load F and pressure loss-derived load N were calculated using the filament of Example 1-1 and the following molding conditions. Molding conditions and equipment: 3D printer (Raise3D, model number Raise3D pro3HS) S: Filament feed rate by extrusion mechanism 251 mm / min L1: Length of material holding section 13 mm D1: Inner diameter of material holding section 2 mm v1: Fluid velocity of molding material passing through material holding section 3.2 mm / s λ1: Friction coefficient of material holding section 2.86 × 10 6 Heating section temperature: 300°C Bed temperature: 60°C Nozzle diameter: 0.8 mm Layer height: 0.3 mm

[0258] Measurement conditions for shear viscosity μ1 and μ2: Equipment: Rheometer (TA Instruments, model ARES-G2) Measurement temperature: 300°C

[0259] (Buckling load F) The buckling load F is given by the following formula (I): F = n × π 2 ×E×I / R 2 (I) n: coefficient 1 / 4 E: Young's modulus of the filament 32 MPa I: second moment of area of ​​the filament 0.460 mm 4 R: From the distance of 10 mm from the extrusion mechanism to the material inlet, F was calculated to be 0.363 N.

[0260] (Pressure loss-derived load N) The pressure loss-derived load N (unit: N) is given by the following formula (II): N = {(8π × μ1 × L1 × v1) + (8π × μ2 × L2 × v2)} × 10 -6 (II) μ1: Shear viscosity of the molding material at the material holding section (Pa·s) μ2: Shear viscosity of the molding material at the extrusion section (Pa·s) L1: Length of the material holding section (mm) L2: Length of the extrusion section (mm) v1: Fluid velocity of the molding material passing through the material holding section (mm / s) v2: Fluid velocity of the molding material passing through the extrusion section (mm / s) From these, N = 0.316 N was calculated. A more specific procedure for calculating the pressure loss-derived load N is shown below.

[0261] 1. Derivation of the shear viscosity of the molding material The following formula (1) γ = 4 × (πd 2 / 4)×(S / 60)×(8 / (πD13 (1) d: filament diameter 1.75 mm S: filament feed rate by extrusion mechanism 251 mm / min D1: inner diameter of material holding part 2 mm Therefore, shear rate γ = 12.8 s -1 This was calculated. Furthermore, the measured value of shear viscosity μ1 at the shear rate γ was 260 Pa·s.

[0262] 2. Confirmation of laminar flow The following equation (2) Re = (ρv1D1) / μ (2) ρ: Density of the molding material 0.91 g / cm³ 3 (Values ​​specific to SEBS, obtained based on the water displacement method) v1: Fluid velocity of the molding material passing through the material holding section 3.2 mm / s D1: Inner diameter of the material holding section 2 mm μ1: Shear viscosity 260 Pa·s Therefore, Reynolds number Re = 2.24 × 10 -5 This was calculated. Since the Reynolds number Re was 2100 or less, the fluid flow in Example 1-1 was determined to be laminar flow.

[0263] 3. Calculation of the friction coefficient of the material holding part From the following formula (3) λ = 64 / Re (3), the friction coefficient λ of the material holding part is 2.86 × 10 6 This was the calculated result.

[0264] 4. Calculation of pressure loss in the material holding section The following formula (4) Δh1 = λ1 × (L1 / D1) × (ρv1 2 / 2) (4) λ1: Friction coefficient of the material holding part 2.86 × 10 6 L1: Length of material holding section 13 mm D1: Inner diameter of material holding section 2 mm v1: Fluid velocity of the material passing through the material holding section 3.2 mm / s ρ: Density of the material 0.91 g / cm³ 3 (A value specific to SEBS, obtained based on the underwater displacement method) Therefore, pressure loss Δh1 = 8.65 × 10 4 It was calculated as (Pa).

[0265] 5. Calculation of load due to pressure loss in the material holding section The following formula (5) N1 = Δh1 × A1 (5) Δh1: pressure loss 8.65 × 10 4 (Pa) A1: Cross-sectional area of ​​the material holding part 1π × 10 -6 I understand 2Therefore, the load N1 originating from the pressure loss in the material holding section is: N1 = 8.65 × 10 4 (Pa) × 1π × 10 -6 (m 2 The calculated value was 0.272 N.

[0266] 6. Calculation of Load Due to Pressure Loss at the Discharge Section The load N2 (N) due to pressure loss at the discharge section was calculated using the same procedure as in 1 to 5 above, except that "material holding section" was replaced with "discharge section". The conditions for the discharge section are as follows: λ2: coefficient of friction of the discharge section 1.40 × 10 6 L2: Length of the extrusion section 1.5 mm D2: Inner diameter of the extrusion section 1.4 mm v2: Fluid velocity of the molding material passing through the extrusion section 6.5 mm / s A2: Cross-sectional area of ​​the extrusion section (0.7) 2 ×π×10 -6 I understand 2 (The arithmetic mean of the inner diameter of the boundary between the material holding section and the dispensing section and the inner diameter of the dispensing port)

[0267] Based on the above, the pressure loss Δh2 at the discharge section is 2.88 × 10⁻⁶. 4 (Pa) is obtained, and the load N2 derived from the pressure loss Δh2 is N2 = 2.88 × 10 4 (Pa) × (0.7) 2 ×π×10 -6 (m 2 The calculated value was 0.044 N.

[0268] 7. The load originating from the pressure loss in both the material holding section and the discharge section is calculated as the pressure loss-derived load N. The load N1 calculated in 5. above and the load N2 calculated in 6. above are added together to calculate the pressure loss-derived load N, which is the load originating from the pressure loss in both the material holding section and the discharge section, to be 0.316 N.

[0269] In Example 1-1, the ratio of buckling load F (0.363 N) to pressure loss-derived load N (0.316 N) was 1 or greater. That is, it can be predicted that buckling will not occur with the combination of molding material and molding conditions described in Example 1-1.

[0270] Furthermore, when a printed object was manufactured using the filament of Example 1-1 under the above printing conditions, no filament buckling occurred.

[0271] The same evaluation was performed for Examples 1-2 to 1-11, 1-13, and Comparative Examples 1-1 to 1-3. The results are shown in Tables 1 and 2. In the above examples, the load N due to pressure loss is calculated using the following formula (II) based on the factors shown in Tables 3 and 4: N = {(8π × μ1 × L1 × v1) + (8π × μ2 × L2 × v2)} × 10 -6 (II) μ1: Shear viscosity of the molding material at the material holding section (Pa·s) μ2: Shear viscosity of the molding material at the extrusion section (Pa·s) L1: Length of the material holding section (mm) L2: Length of the extrusion section (mm) v1: Fluid velocity of the molding material passing through the material holding section (mm / s) v2: Fluid velocity of the molding material passing through the extrusion section (mm / s) These values ​​were used for calculation.

[0272] <Pellets> [Examples 2-1 to 2-11] The pellets obtained in each of Examples 1-1 to 1-11 were used as thermoplastic elastomer resin compositions. The molded objects were manufactured using the same procedure as in Example 1-1, except that the molding conditions were the same as those described in the section on molding conditions for pellets.

[0273] [Example 2-12] Using the pellets obtained in Example 1-10, a test specimen measuring 300 mm in length, 100 mm in width, and 80 mm in thickness was fabricated using a 3D printer (EXT 1070 Titan Pellet, 3D SYSTEMS) at an ambient temperature of 80°C, a nozzle temperature of 265°C, a bed temperature of 65°C, and a nozzle diameter of 1 mm. The infill of the fabricated object was set to a gyroid shape with a filling density of 10%, and half of the longitudinal side of the fabricated object was covered with two layers of walls, while the other half was fabricated without walls. The resulting fabricated object was as designed, with half covered by walls and the other half without walls, and had an excellent appearance.

[0274] Tables 5 and 6 show the measurement and evaluation results of the pellets and the molded objects produced using those pellets. In Examples 2-1 to 2-6 and 2-8 to 2-11, the pellets were dried in a vacuum dryer at 80°C for 24 hours before each molding process. The pellets in Example 2-7 were not dried before molding.

[0275] [Comparative Examples 2-1 to 2-3] Evaluations were performed in the same manner as in Example 2-1 using the pellets described in Tables 5 and 6. The measurement and evaluation results for the pellets and molded objects are shown in Tables 5 and 6. When molding using the pellets of Comparative Example 2-2, masking tape was applied to the bed before molding.

[0276]

[0277]

[0278]

[0279]

[0280]

[0281]

[0282] Tables 1 to 6 show that the thermoplastic elastomer resin compositions of the embodiments according to the present invention have an excellent balance between moldability and flexibility of the molded object, and can create molded objects with a large difference in hardness.

[0283] In contrast, the thermoplastic elastomer resin composition of Comparative Example 1-1 has a ratio of the minimum hardness of the molded object to the hardness of the thermoplastic elastomer resin composition, and its flexibility index is greater than 65%, resulting in poor moldability, insufficient flexibility, and a small difference in hardness within the molded object. Furthermore, the thermoplastic elastomer resin composition of Comparative Example 1-2 is unsuitable for molding due to its material composition, and therefore cannot be molded. Finally, the resin composition of Comparative Example 1-3 does not use a thermoplastic elastomer, resulting in low flexibility.

[0284] Furthermore, as can be seen from Tables 1 to 6, the embodiments according to the present invention have less aggregate than the comparative examples and exhibit superior tensile elongation, warping suppression, and shrinkage suppression. In addition, since the infill structure can be exposed during fabrication, it is possible to provide fabricated objects with excellent design.

[0285] According to the present invention, a thermoplastic elastomer resin composition with good moldability and flexibility can be provided, and such a thermoplastic elastomer resin composition can be used in a wide range of applications, including automotive applications, space equipment such as rockets and artificial satellites, drones, prosthetics and orthotics, grips, cases, and more.

Claims

1. A molded product which is an additive product of a thermoplastic elastomer resin composition, wherein the minimum hardness of the molded product is 65% or less of the hardness of the thermoplastic elastomer resin composition, and the hardness is measured by a hardness tester in accordance with ISO 7619.

2. The molded product according to claim 1, wherein the thermoplastic elastomer resin composition comprises a styrene-based elastomer and cellulose fibers.

3. The molded product according to claim 1, wherein the thermoplastic elastomer resin composition includes an acid-modified elastomer.

4. The molded product according to claim 1, wherein the Shore A hardness of the thermoplastic elastomer resin composition is 35A to 75A.

5. The molded product according to claim 1, wherein the elastic modulus of the thermoplastic elastomer resin composition at 10% elongation is 10 MPa or more.

6. The molded object according to claim 1, wherein the molded object has a surface layer and an infill layer, and the infill layer is exposed on the surface at one or more locations.

7. The molded object according to claim 1, wherein the minimum value of the Shore A hardness of the molded object is 30A or less.

8. The molded object according to claim 1, wherein the Shore A hardness ratio, calculated using the following formula: (Shore A hardness ratio) = (Minimum Shore A hardness in the molded object) / (Maximum Shore A hardness in the molded object), is 65% or less.

9. A method for manufacturing a molded object according to any one of claims 1 to 8, comprising molding a thermoplastic elastomer resin composition using a 3D printer.

10. The method according to claim 9, wherein the thermoplastic elastomer resin composition is supplied to the 3D printer as a filament-like 3D printing material, and the molten 3D printing material is extruded from the extrusion port of the 3D printer.

11. The method according to claim 10, wherein the filament is melted in the heating section of the 3D printer, the molten fluid is discharged from the discharge port of the heating section, the ratio F / N of the buckling load F of the filament to the pressure loss load N applied to the filament due to the pressure loss of the fluid in the heating section is 1 to 20, and the Young's modulus of the filament is 50 MPa or less.

12. The method according to claim 9, wherein the thermoplastic elastomer resin composition is extruded from the nozzle of the 3D printer and additively manufactured, and the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D of the nozzle (Pmax / D) is 0.05 or more and less than 0.

5.

13. A thermoplastic elastomer resin composition for additive manufacturing, wherein the flexibility index of the thermoplastic elastomer resin composition is 65% or less, and the flexibility index is the value obtained by dividing the hardness of the upper center of the dome shape of a test mold obtained by molding the thermoplastic elastomer resin composition to have a dome-shaped outer wall with a width of 63 mm x depth of 82 mm x height of 15 mm, a gyroid-shaped infill with a filling rate of 10%, two bottom layers in the 45° and 135° directions, and eight solid layers arranged concentrically by the hardness of the thermoplastic elastomer resin composition, and the hardness is measured by a hardness tester in accordance with ISO 7619.

14. The thermoplastic elastomer resin composition according to claim 13, wherein when the thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and additively manufactured, the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D (Pmax / D) is 0.05 or more and less than 0.5.

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