Thermoplastic elastomer resin composition for additive manufacturing, and method for manufacturing molded objects

Abstract

To provide a thermoplastic elastomer resin composition that can prevent deformation and achieve desired flexibility even when creating molded objects with low filling density or large height dimensions, and a method for manufacturing molded objects using the thermoplastic elastomer resin composition. [Solution] A method for manufacturing a molded object which is an additive product of a thermoplastic elastomer resin composition, wherein the method includes extruding the thermoplastic elastomer resin composition from the nozzle of a 3D printer and performing additive manufacturing, wherein the ratio of the layer pitch P to the nozzle diameter D of the nozzle (P / D) is 0.05 or more and less than 0.5, and the actual dimensions of the molded object in the width direction or thickness direction are within ±10% of the set dimensions of the 3D printer.

Description

Technical Field

[0001] The present invention relates to a thermoplastic elastomer resin composition for additive manufacturing, a method for manufacturing a shaped object using the thermoplastic elastomer resin composition, and the like.

Background Art

[0002] As an additive manufacturing technology using a 3D printer or the like, there is a method (material extrusion method) of extruding and laminating a shaping material such as a heated filament. In recent years, further improvement research and development have been carried out on materials, processes, etc. because this material extrusion method has advantages such as not requiring a mold for shaping and having a high degree of freedom in the shape of the shaped object.

[0003] As thermoplastic elastomer materials used in the material extrusion method, those that devise the Shore A hardness of the thermoplastic elastomer (for example, Patent Document 1) and those that devise the composition of the thermoplastic elastomer (for example, Patent Document 2) have been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when any of the conventional shaping materials is used for shaping a shaped object with a low filling rate or a large height dimension, the shaping may be disturbed or the desired flexibility of the shaped object may not be obtained.

[0006] In view of the state of prior art, the problem that the present invention aims to solve is to provide a thermoplastic elastomer resin composition that can prevent deformation and achieve desired flexibility even when creating molded objects with a low filling rate or large height dimension, and a method for manufacturing molded objects using the thermoplastic elastomer resin composition. [Means for solving the problem]

[0007] The gist of this invention is as follows: [Item 1] A method for manufacturing a molded product which is an additive product of a thermoplastic elastomer resin composition, The method includes extruding a thermoplastic elastomer resin composition from the nozzle of a 3D printer and performing additive manufacturing. The ratio of the stacking pitch P to the nozzle diameter D of the nozzle (P / D) is 0.05 or more and less than 0.5. A method wherein the actual dimensions of the molded object in the width direction or thickness direction are within ±10% of the set dimensions in the 3D printer. [Item 2] The method according to item 1, wherein the actual dimensions of the molded object in the width direction and thickness direction are within ±10% of the set dimensions in the 3D printer. [Item 3] The method according to item 1 or 2, wherein the thermoplastic elastomer resin composition comprises a styrene-based elastomer and cellulose fibers. [Item 4] The method according to any one of items 1 to 3, wherein the thermoplastic elastomer resin composition includes an acid-modified elastomer. [Item 5] The method according to any one of items 1 to 4, wherein the thermoplastic elastomer resin composition is in the form of filaments. [Item 6] The method according to any one of items 1 to 5, wherein the Shore A hardness of the thermoplastic elastomer resin composition is 40A to 75A. [Item 7] A thermoplastic elastomer resin composition for additive manufacturing, A thermoplastic elastomer resin composition in which, when the thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and layer-built, 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. [Item 8] The thermoplastic elastomer resin composition according to item 7, wherein the ratio of the minimum buildable layer thickness Pmin to the nozzle diameter D of the nozzle (Pmin / D) is 0.01 or more and 0.04 or less. [Item 9] A thermoplastic elastomer resin composition according to item 7 or 8, comprising a styrene-based elastomer and cellulose fibers. [Item 10] A thermoplastic elastomer resin composition according to any one of items 7 to 9, comprising an acid-modified elastomer. [Item 11] The thermoplastic elastomer resin composition according to any one of items 7 to 10, which is in the form of a filament. [Item 12] A thermoplastic elastomer resin composition according to any of items 7 to 11, wherein the Shore A hardness is 40A to 75A. [Effects of the Invention]

[0008] According to the present invention, a thermoplastic elastomer resin composition is provided that can prevent deformation and achieve desired flexibility even when creating molded objects with a low filling density or large height dimensions, and a method for manufacturing molded objects using the thermoplastic elastomer resin composition is also provided. [Modes for carrying out the invention]

[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 thermoplastic elastomer resin composition, and more particularly, a thermoplastic elastomer resin composition for additive manufacturing. Another aspect of the present invention also provides a method for manufacturing a molded product which is an additive product of the thermoplastic elastomer resin composition. The thermoplastic elastomer resin composition is a composition comprising a thermoplastic elastomer. In one embodiment, the thermoplastic elastomer resin composition comprises a styrene-based elastomer and cellulose fibers. In one embodiment, the thermoplastic elastomer resin composition comprises an acid-modified elastomer.

[0011] In this disclosure, “additive manufacturing” refers to a process of constructing a three-dimensional object by progressively adding (layering) materials, in contrast to subtractive manufacturing, such as machining. 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 of this embodiment 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. In one embodiment, the thermoplastic elastomer resin composition of this embodiment is a thermoplastic elastomer resin composition for 3D printing, and in another embodiment, it is a thermoplastic elastomer resin composition for material extrusion deposition (MEX). In the following, the thermoplastic elastomer resin composition of this embodiment will be described in more detail, with appropriate reference to the exemplary configuration in the case of material extrusion lamination (MEX).

[0012] The use of thermoplastic elastomer resin compositions makes it possible to form flexible objects. However, due to their viscoelastic properties, thermoplastic elastomer resin compositions are prone to causing deformation. This deformation is particularly likely to occur when forming objects with low fill density or large height dimensions. In order to suppress deformation and achieve the desired flexibility of the object, it is desirable that the thermoplastic elastomer resin composition forms the internal structure of the object with appropriate rigidity and is laminated with good adhesion. The inventors have found that thermoplastic elastomer resin compositions that exhibit specific properties when extruded from a 3D printer nozzle and subjected to additive manufacturing are useful.

[0013] (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 for additive manufacturing, the ratio of the maximum buildable layer pitch Pmax to the nozzle diameter D (Pmax / D) (also referred to as the maximum buildable layer pitch coefficient in this disclosure) is 0.05 or more and less than 0.5. With respect to the layer pitch, "buildable" means that the actual dimensions of the manufactured object (specifically, the dimensions in the width direction and thickness direction of a strip-shaped test piece) are within ±10% of the 3D printer set dimensions. The set dimensions are the dimensions set by loading the desired model shape into the 3D printer, directly inputting each parameter, etc. In this disclosure, the maximum buildable layer pitch Pmax means the maximum value among the 3D printer set values ​​for layer pitch that was "buildable" as described above, and the minimum buildable layer pitch Pmin means the minimum value among the 3D printer set values ​​for layer pitch that was "buildable" as described above.

[0014] When layers are stacked at a stacking pitch exceeding the maximum buildable stacking pitch Pmax, insufficient pressure may be applied to the stacked surfaces during printing, or the stacked layers may not have sufficient bonding area, potentially leading to build defects or stacking failures. Methods to increase the maximum buildable stacking pitch coefficient include adjusting the viscosity and modulus of the thermoplastic elastomer resin composition so that good adhesion is possible even with less pressure and contact area. More specifically, 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) should be 50 or more. For example, the lower the viscosity, the easier it is for the thermoplastic elastomer resin composition to spread on the build surface after being extruded from the nozzle, resulting in better stacking adhesion. Conversely, the higher the modulus of elasticity, the more stably the thermoplastic elastomer resin composition is extruded, resulting in better stacking adhesion. However, if the maximum build pitch coefficient is too large, although the build pitch can be increased and productivity is good, with soft materials such as elastomers, the following disadvantages may occur: (1) poor build accuracy when the build pitch is small, (2) the tackiness of the built object becomes strong due to excessively low viscosity and / or excessively high elastic modulus, and (3) the built object becomes hard. From the above viewpoint, the maximum build pitch coefficient is less than 0.5 in one embodiment, preferably 0.40 or less, or 0.38 or less. In particular, it has been thought that a larger maximum build pitch coefficient is advantageous from the viewpoint of the degree of freedom of build conditions. Contrary to this conventional technical common sense, in this embodiment, it has been found that if the maximum build pitch coefficient is too large, the dimensional accuracy of the built object is good but the above disadvantages occur, and attention is paid to setting the maximum build pitch coefficient to a predetermined level or less. On the other hand, if the maximum build pitch coefficient is too small, the number of layers required to obtain a built object of the desired size increases, resulting in low build efficiency. From the above viewpoint, the maximum molding pitch coefficient is 0.05 or more in one embodiment, preferably 0.10 or more, or 0.15 or more.

[0015] The ratio of the minimum buildable layer thickness Pmin to the nozzle diameter D (Pmin / D) (also referred to as the minimum build pitch coefficient in this disclosure) is small, as it enables the manufacture of highly detailed molded objects. From this viewpoint, the minimum build pitch coefficient is preferably 0.04 or less, or 0.03 or less. From the viewpoint of the availability of thermoplastic elastomer resin compositions, the minimum build pitch coefficient may, in one embodiment, be 0.01 or more, or 0.02 or more.

[0016] The buildable layer thickness is a value determined by the method described in the [Examples] section of this disclosure.

[0017] The maximum or minimum molding pitch coefficient can be adjusted by setting the viscosity and modulus (in one embodiment, modulus at 10% elongation) of the thermoplastic elastomer resin composition to an appropriate range. In one embodiment, the ratio of modulus to viscosity is set to a specific range. The viscosity and modulus of the thermoplastic elastomer resin composition can be controlled by adjusting the properties of the thermoplastic elastomer (viscosity, modulus), the type and / or amount of additives such as cellulose fibers, etc.

[0018] Whether a certain layer thickness can be fabricated depends on process conditions such as nozzle diameter, nozzle temperature, bed temperature, and fabrication speed. The maximum and minimum fabrication pitch coefficients for the manufacturing method of the fabricated object in this embodiment are the values ​​when the process conditions are those used during the actual fabrication of the fabricated object. On the other hand, the maximum and minimum fabrication pitch coefficients for the thermoplastic elastomer resin composition of this embodiment or the fabricated object obtained using it are intended to be the values ​​under process conditions that are expected to be typical for the fabrication of the thermoplastic elastomer resin composition. Specifically, the values ​​are obtained when the ambient temperature is room temperature (23°C), the nozzle diameter is 0.8 mmΦ, the nozzle temperature is 300°C for styrene-based elastomers, 240°C for urethane-based elastomers, 230°C for ester-based elastomers, and 280°C for other elastomers, the bed temperature is 60°C for styrene-based elastomers and 23°C for other elastomers, the printing speed is 20 mm / second, and the thermoplastic elastomer resin composition is sufficiently dried before printing.

[0019] (Thermoplastic elastomer resin composition, flexibility index of molded object) In one embodiment of a thermoplastic elastomer resin composition or molded object, the flexibility index determined by the following method is 65% or less. 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 formed from a thermoplastic elastomer resin composition having a dome-shaped outer wall measuring 63 mm wide x 82 mm deep x 15 mm high, a gyroid-shaped infill with a filling rate of 10%, two bottom layers in the 45° and 135° directions, and eight concentric solid layers, 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 using a test specimen in accordance with ISO 37 type 3. More detailed measurement methods are described in the [Examples] section of this disclosure.

[0020] 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.

[0021] The design of the shape of a fabricated object can be carried out by loading the desired model shape into an additive manufacturing device (more specifically, a 3D printer), directly inputting various parameters, etc. The shape of the test object can be set in the 3D printer as follows: The dome shape is specifically a rectangular base with rounded corners (i.e., R-shaped) with sides of 20 mm. In side view, the base is horizontal, and both side walls have a curved shape with a radius of R15 mm. The gyroid shape and its infill ratio 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.

[0022] 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, and even more preferably 35% or less, or 30% or less. In this case, there is an excellent balance between the formability of the thermoplastic elastomer resin composition and the flexibility of the molded object. A lower flexibility index 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.

[0023] 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.

[0024] 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.

[0025] (Average fiber length of 10% of cellulose fibers contained in thermoplastic elastomer resin composition) In one embodiment, the 10% average fiber length of the 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 10% average fiber length of the cellulose fibers within the above range 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.

[0026] 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 within 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.

[0027] 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.

[0028] (Processing by ImageJ) In one aspect, processing using 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 > Threshold (Triangle)) 5. 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 Treshold:0.00, Upper Treshold:0.17, Minimum Line Length:20, Maximum Line Length:0.00)

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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. There is no particular upper limit, 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.

[0033] 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.

[0034] (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. Furthermore, from the viewpoint of mold stability, 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 is preferred. The hardness of a thermoplastic elastomer resin composition is a value measured using a hardness tester in accordance with ISO 7619. The hardness of a 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 elastomer may be within the above range.

[0035] (Modular modulus of thermoplastic elastomer resin composition at 10% elongation) In one embodiment, the elastic modulus of the thermoplastic elastomer resin composition at 10% elongation is preferably 10 MPa or higher, and more preferably 20 MPa or higher, from the viewpoint of mold stability and reduction of shrinkage during molding. Furthermore, from the viewpoint of flexibility of the molded product, it is preferably 100 MPa or lower, and more preferably 50 MPa or lower. The modulus of elasticity at 10% elongation of a thermoplastic elastomer resin composition 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.

[0036] (Thermoplastic elastomer resin composition, viscosity of thermoplastic elastomer) The viscosity (melt flow rate) of the thermoplastic elastomer resin composition and the thermoplastic elastomer is preferably within a predetermined range in terms of balancing moldability and the flexibility of the molded object. 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 manufactured product due to resin dripping from the nozzle and a decrease in dimensional accuracy.

[0037] 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.

[0038] (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 object (more specifically, achieving a desired surface roughness), improving the physical properties of the molded object, and improving the dimensional accuracy of the molded object.

[0039] The water absorption rate of thermoplastic elastomer resin compositions is measured using a Karl Fischer moisture meter in accordance with ISO 15512.

[0040] 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.

[0041] (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 standpoint of improving the dimensional accuracy of the molded object, reducing extrusion defects during molding, reducing the voids in the molded object, and improving the physical properties of the molded object.

[0042] 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 fiber diameter of the cellulose fibers contained in the thermoplastic elastomer resin composition, and the temperature conditions during the manufacturing of the thermoplastic elastomer resin composition.

[0043] (Agglomerates contained in thermoplastic elastomer resin compositions) 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 in the 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.

[0044] <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 between 1 MPa and 100 MPa.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] A block copolymer may be a copolymer consisting of two or more blocks. For example, a block copolymer may have a structure such as AB, ABA, or ABAB, 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 between 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 tapered. Furthermore, block B may have multiple portions where the aromatic vinyl monomer is uniformly distributed and / or tapered. 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.

[0050] 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.

[0051] 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.

[0052] In one embodiment, the styrene elastomer may be unmodified, modified, for example, acid-modified, or a mixture thereof.

[0053] 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.

[0054] 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 created using the characteristic absorption band of the acid, after measuring a calibration curve sample that has been pre-mixed with an acidic substance using an infrared absorption spectrum analyzer.

[0055] 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 counterpart with or without 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 an acid anhydride-modified styrene elastomer.

[0056] 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 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.

[0057] 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).

[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 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.

[0059] When an acid-modified styrene elastomer is used in combination with a styrene elastomer other than the acid-modified styrene elastomer, the ratio of styrene units 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.

[0060] 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 a conjugated diene bond unit (e.g., the amount of 1,2-bonds in butadiene) is, 13 This can be determined by 13C-NMR (quantitative mode). That is, 13 In 1C-NMR, integrating the peak areas shown below yields a value proportional to the carbon content of each structural unit, which can then 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

[0061] 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 be preferably 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.

[0062] 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.

[0063] 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.

[0064] In one embodiment, the amount of thermoplastic elastomer in 100% by mass of the thermoplastic elastomer resin composition is 60% by mass or more, or 65% by mass or more, or 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, or 85% by mass or less, or 80% by mass or less, in one embodiment.

[0065] 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 filament printing, 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 filament printing, shrinkage suppression during printing, 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.

[0066] 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 tensile stress (suppression of void formation) of the molded product. 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 extrusion stability during molding using filaments, suppressing shrinkage during molding, and / or suppressing a decrease in the 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.

[0067] 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 portion of the cellulose fibers (specifically, the portion that provides surface area in the specific surface area measurement of the cellulose fibers). The number of hydroxyl groups on the surface portion 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.

[0068] 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 hardness reduction caused by the acid-modified styrene elastomer.

[0069] The amount of acid-modified styrene 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 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 elastomer is generally relatively expensive, so reducing the amount used is advantageous from a cost perspective.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] <Cellulose fiber> In this embodiment, the thermoplastic elastomer resin composition preferably contains cellulose fibers from the viewpoint of moldability, suppression of shrinkage of molded objects, suppression of warping, and interlayer adhesion.

[0075] 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 mechanically crushing, fibrillating, or refining them 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.).

[0076] Cellulose fibers are obtained by mechanically micronizing cellulose raw materials using a dry or wet process. This micronization process may be performed using a single device one or more times, or by using multiple devices, each one or more times.

[0077] The equipment used for micronization is not particularly limited, but examples include high-speed rotary, colloidal mill, high-pressure, roll mill, and ultrasonic types of equipment. High-pressure or ultra-high-pressure homogenizers, refiners, beaters, PFI mills, kneaders, dispersers, high-speed defibrators, grinders (stone mill type grinders), ball mills, vibratory mills, bead mills, conical refiners, disc refiners, single-screw, twin-screw or multi-screw kneaders / extruders, homomixers under high-speed rotation, refiners, defibrators, beaters, friction grinders, high-shear fibrilators (e.g., Cavitron rotor / starter devices), dispersers, homogenizers (e.g., microfluidizers), etc., which use metal or blades to act on pulp fibers around a rotating shaft, or those that use friction between pulp fibers.

[0078] In one embodiment, cellulose fibers can be obtained as a slurry. The slurry can be prepared by dispersing and micronizing the cellulose fiber raw material in water and / or other media (e.g., organic solvents, inorganic acids, bases and / or ionic liquids).

[0079] The organic solvent used in the aforementioned micronization process is not particularly limited, but examples include: alcohols with 1 to 20 carbon atoms, preferably 1 to 4 carbon atoms, such as methanol, ethanol, and propanol; glycol ethers with 2 to 20 carbon atoms, preferably 2 to 6 carbon atoms, such as methyl cellosolve and propylene glycol monomethyl ether; ethers with 2 to 20 carbon atoms, preferably 2 to 8 carbon atoms, such as propylene glycol monomethyl ether, 1,2-dimethoxyethane, diisopropyl ether, tetrahydrofuran, and 1,4-dioxane; acetone; methyl ethyl ketone; and Examples include ketones with 3 to 20 carbon atoms, preferably 3 to 6 carbon atoms, such as ethyl isobutyl ketone; linear or branched saturated or unsaturated hydrocarbons with 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms; aromatic hydrocarbons such as benzene and toluene; halogenated hydrocarbons such as methylene chloride and chloroform; carboxylic acids with 1 to 20 carbon atoms, such as formic acid, acetic acid, and lactic acid; esters with 2 to 20 carbon atoms, preferably 2 to 6 carbon atoms, such as ethyl acetate and vinyl acetate; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; and sulfur-containing solvents such as dimethyl sulfoxide. These can be used individually or in combination of two or more, but from the viewpoint of ease of operation in the micronization process, alcohols with 1 to 6 carbon atoms, glycol ethers with 2 to 6 carbon atoms, ethers with 2 to 8 carbon atoms, ketones with 3 to 6 carbon atoms, lower alkyl ethers with 2 to 5 carbon atoms, carboxylic acids with 1 to 8 carbon atoms, esters with 2 to 6 carbon atoms, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide are preferred.

[0080] Examples of inorganic acids include hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and boric acid. However, from the viewpoint of efficiency of defibrillation and ease of handling, it is preferable to use one or more selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0081] Examples of bases include hydroxides such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; carbonates such as sodium carbonate, potassium carbonate, and calcium carbonate; and organic amines such as ammonia, triethylamine, and triethanolamine. However, from the viewpoint of efficiency of defibrillation and ease of handling, it is preferable to use one or more selected from the group consisting of hydroxides, carbonates, and organic amines.

[0082] In this disclosure, an ionic liquid refers to a salt of a liquid containing an organic ion in at least one of its cation and anion portions, with a melting point of ions only of 100°C or lower. Preferably, the ionic liquid has at least one cation selected from the group consisting of imidazolium cation, pyrrolidinium cation, piperidinium cation, morpholinium cation, pyridinium cation, quaternary ammonium cation, and phosphonium cation in its cation portion.

[0083] In particular, ionic liquids having an imidazolium skeleton, for example, the following formula (1):

[0084] [ka]

[0085] (In the formula, R1 and R2 each independently represent an alkyl group or allyl group having 1 to 8 carbon atoms, and X represents an anion.) The imidazolium-based ionic liquid shown is more preferable than other ionic liquids because it has a relatively low melting point, a wide temperature range in which it exists as a liquid, maintains fluidity even at low temperatures, and has excellent thermal stability. From the viewpoint of defibrillability, the number of carbon atoms in R1 and R2 is more preferably 4 or less, even more preferably 3 or less, and most preferably 2 or less.

[0086] The anionic component is a halide ion (Cl - , Br - , I - (etc.), carboxylic acid anions (for example, carboxylic acid anions with a total of 1 to 3 carbon atoms, e.g., C2H5CO) 2- CH3CO2- , HCO2 - etc.), pseudo-halide ions (i.e., ions that are monovalent and have properties similar to halide ions, for example, CN - , SCN - , OCN - , ONC - , N 3- etc.), sulfonic acid anions, organic sulfonic acid anions (such as methanesulfonic acid anion), phosphate anions (such as ethyl phosphate anion, methyl phosphate anion, hexafluorophosphate anion), borate anions (such as tetrafluoroborate anion), perchlorate anions, etc. From the viewpoint of fibrillation property, halide ions and carboxylic acid anions are preferred.

[0087] Examples of imidazolium-based ionic liquids include 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium formate, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium dimethyl phosphate, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium diethyl phosphate, 1,3-dimethylimidazolium acetate, 1-ethyl-3-methylimidazolium propionate, 1-propyl-3-methylimidazolium chloride, 1-propyl-3-methylimidazolium bromide, etc.

[0088] While it is possible to defibrillate cellulose fiber raw materials using only ionic liquids, if the solubility of the ionic liquid is too high and there is a risk of dissolving the cellulose fibers, it is preferable to add water and / or an organic solvent to the ionic liquid. The type of organic solvent to be added should be appropriately selected considering its compatibility with the ionic liquid, affinity for cellulose, solubility of the mixed solvent in the cellulose fiber raw materials, viscosity, etc., but it is preferable to select one or more from the group consisting of N,N-dimethylacetamide, N,N-dimethylformamide, 1-methyl-2-pyrrolidone, dimethyl sulfoxide, acetonitrile, methanol, and ethanol.

[0089] The total amount of water and / or other media used in the micronization process is not particularly limited, as long as it is an effective amount that can disperse the cellulose fiber raw material. However, it is preferably 1 mass or more, more preferably 10 mass or more, even more preferably 50 mass or more, preferably 10,000 mass or less, more preferably 5,000 mass or less, even more preferably 2,000 mass or less, and particularly preferably 1,000 mass or less, relative to the cellulose fiber raw material.

[0090] Since cellulose fiber raw materials contain alkali-soluble components and sulfuric acid-insoluble components (such as lignin), these components may be reduced through purification processes such as deligninization by pulping and bleaching. On the other hand, purification processes such as deligninization by pulping and bleaching cleave the molecular chains of cellulose, changing the weight-average molecular weight and number-average molecular weight. Therefore, it is desirable that the purification and bleaching processes of cellulose fiber raw materials be controlled so that the weight-average molecular weight of the cellulose fiber and the ratio of weight-average molecular weight to number-average molecular weight are within an appropriate range.

[0091] Furthermore, there are concerns that the cellulose fibers will become lower in molecular weight due to purification processes such as lignin removal through pulping, and that the cellulose fiber raw material will be altered, increasing the proportion of alkali-soluble components. Since alkali-soluble components have poor heat resistance, it is desirable that the purification and bleaching processes of the cellulose fiber raw material be controlled so that the amount of alkali-soluble components contained in the cellulose fiber raw material remains below a certain value.

[0092] In one embodiment, the cellulose fiber raw material may be chemically modified, and inorganic esters such as nitrate esters, sulfate esters, phosphate esters, silicate esters, and borate esters, organic esters such as acetylated and propionylated compounds, ethers such as methyl ethers, hydroxyethyl ethers, hydroxypropyl ethers, hydroxybutyl ethers, carboxymethyl ethers, and cyanoethyl ethers, and TEMPO oxides obtained by oxidizing the primary hydroxyl groups of cellulose can be used as the cellulose fiber raw material.

[0093] [Number-average fiber length, number-average fiber diameter, and L / D ratio of cellulose fiber raw materials] 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. More preferably, the number-average fiber diameter of the cellulose fiber raw material 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.

[0094] 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 with a small amount of cellulose fiber. There is no particular upper limit, 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.

[0095] In one embodiment, the number-average fiber diameter (D), number-average fiber length (L), and L / D ratio of the cellulose fiber raw material of this disclosure are values ​​measured using a scanning electron microscope (SEM) by the following procedure. The aqueous dispersion of the cellulose fiber raw material is replaced with tert-butanol, diluted to 0.001-0.1% by mass, dispersed using a high-shear homogenizer (e.g., IKA product, trade name "Ultra-Turrax T18") under processing conditions: rotation speed 15,000 rpm × 3 minutes, cast onto an osmium-deposited silicon substrate, air-dried, and used as 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 fiber raw material, the number-average values ​​of length (L), diameter (D), and ratio (L / D) are calculated.

[0096] [BET specific surface area] In one embodiment, the BET specific surface area of ​​the cellulose fiber is preferably 2m, from the viewpoint of obtaining a good effect of improving physical properties by the cellulose fiber and from the viewpoint of improving the dispersibility of the cellulose fiber in the resin composition or the 3D printing material. 2 / g or more, preferably 3m 2 / g or more, preferably 5m 2 / g or more, preferably 7m 2 / g or more, preferably 10m 2 / g or more, preferably 12m 2 / g or more, preferably 15m 2 / g or more, preferably 17m 2 / g or more, preferably 20m2 / g or more, preferably 22m 2 / g or more, preferably 25m 2 / g or more, preferably 27m 2 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 Less than or equal to / g, preferably 350m 2 Less than or equal to / g, preferably 300m 2 Less than or equal to / g, preferably 250m 2 Less than or equal to / g, preferably 200m 2 Less than or equal to / g, preferably 170m 2 Less than or equal to / g, preferably 150m 2 Less than or equal to / g, preferably 120m 2 Less than or equal to / g, preferably 100m 2 The specific surface area is less than or equal to / g. The specific surface area is measured for porous cellulose fiber sheets using a specific surface area and pore distribution analyzer (e.g., Nova-4200e, manufactured by Quantachrome Instruments) with nitrogen gas. Specifically, approximately 0.2g of the porous sheet is dried under vacuum at 120°C for 5 hours, and then 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. The BET specific surface area (m²) is then 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.

[0097] 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.

[0098] The density of cellulose is 1.5 g / cm³. 3 Therefore, the volume per gram of cellulose is 6.7 × 10 -7 (m 3 It is / g). If the equivalent fiber diameter of a cellulose fiber is r (m), then the average outer circumference of the cellulose fiber is πr, and the average cross-sectional area of ​​the cellulose fiber is 0.25πr. 2Therefore, 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 (m²) 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, Equivalent fiber diameter r(m) = 26.68 × 10 -7 (m 3 / g) / specific surface area (m 2 / g) For example, 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.

[0099] 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.

[0100] [Crystallization] The degree of crystallinity of the cellulose fibers is preferably 55% or higher. When the degree of crystallinity is within this range, the mechanical properties (strength, dimensional stability) of the cellulose itself are high, and therefore, when 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 degree of crystallinity is 60%, even more preferably 70%, and most preferably 80%. There is no particular upper limit for the degree of crystallinity of the cellulose fibers, and a higher degree is preferable, but from a production standpoint, a preferable upper limit is 99%. On the other hand, if the degree of 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 degree of crystallinity can be 99% or less, 95% or less, or 90% or less.

[0101] The degree of crystallinity referred to here, when the cellulose is type I cellulose crystal (derived from natural cellulose), can be determined by the Segal method from the diffraction pattern (2θ / deg. of 10 to 30) obtained by measuring the sample by wide-angle X-ray diffraction, using the following formula. Crystallinity (%)=[I(200)-I(amorphous)] / I(200)×100 I(200): Diffraction peak intensity due to the 200 plane (2θ=22.5°) in cellulose type I crystals. I (amorphous): The halo peak intensity due to amorphous cellulose in type I crystals, specifically the peak intensity at an angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°).

[0102] 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, from 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. Crystallinity (%) =h1 / h0 ×100

[0103] [Crystal polymorphism] Known crystalline polymorphs of cellulose include type I, type II, type III, and type IV. Among these, types I and II are particularly widely used, while types III and IV, although obtained on a laboratory scale, are not widely used on an industrial scale. The cellulose fibers of this disclosure have relatively high structural mobility, and by dispersing these cellulose fibers in a resin, a resin composition with a lower coefficient of thermal expansion and superior strength and elongation during tensile and bending deformation can be obtained. Therefore, 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 crystallinity of 55% or higher are more preferred.

[0104] [Degree of polymerization] Furthermore, 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.

[0105] 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.

[0106] 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)".

[0107] Furthermore, the degree of polymerization of chemically modified cellulose fibers may not be accurately calculated due to the presence of chemical modification groups. In such cases, the degree of polymerization of the cellulose fiber immediately before chemical modification, or the cellulose fiber raw material immediately before chemical modification, may be considered as the degree of polymerization of the chemically modified cellulose fiber.

[0108] [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 another embodiment, the ratio of weight-average molecular weight to 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 weight-average molecular weight to 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 cellulose molecules 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 molecules in the cellulose fiber is not only large, but also when 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 higher, or 2 or higher, 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.

[0109] In addition, accurate calculation of Mw, Mn, and Mw / Mn for chemically modified cellulose fibers may not be possible due to the presence of chemical modification groups. In such cases, the Mw, Mn, and Mw / Mn of the cellulose fiber immediately before chemical modification, or the raw material for the cellulose fiber immediately before chemical modification, may be considered as the Mw, Mn, and Mw / Mn of the chemically modified cellulose fiber.

[0110] The weight-average molecular weight and number-average molecular weight of cellulose fibers referred to here 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.

[0111] [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, resulting in a porous structure inside the fibrous material.

[0112] The hydrolysis method is not particularly limited, but examples include acid hydrolysis, alkaline hydrolysis, hydrothermal decomposition, steam explosion, and microwave decomposition. These methods may be used individually or in combination of two or more. In the acid hydrolysis method, for example, α-cellulose obtained as pulp from fibrous plants is used as the cellulose fiber raw material, and while dispersed in an aqueous medium, an appropriate amount of protic acid, carboxylic acid, Lewis acid, heteropoly acid, etc. is added, and the average degree of polymerization can be easily controlled by heating while stirring. The reaction conditions such as temperature, pressure, and time vary depending on the cellulose species, cellulose concentration, acid species, acid concentration, etc., but are adjusted appropriately to achieve the desired average degree of polymerization. For example, one condition is to use an aqueous solution of mineral acid with a concentration of 2% by mass or less and treat the cellulose fibers at 100°C or higher under pressure for 10 minutes or more. Under these conditions, the catalytic component such as the acid penetrates into the cellulose fiber, promoting hydrolysis, reducing the amount of catalytic component used, and making subsequent purification easier. Furthermore, the dispersion of cellulose fiber raw materials during hydrolysis may contain a small amount of organic solvent in addition to water, as long as it does not impair the effects of the present invention.

[0113] [Alkali-soluble polysaccharides and acid-insoluble components] Between the microfibrils of cellulose fibers and between the bundles of microfibrils, there are alkali-soluble polysaccharides such as hemicellulose and acid-insoluble components such as lignin. Hemicellulose is a polysaccharide composed of sugars such as mannan and xylan, and it plays a role in linking microfibrils together by hydrogen bonding with cellulose. Lignin is a compound with an aromatic ring, and it is known to be covalently bonded with hemicellulose in the cell walls of plants.

[0114] 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 part 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.

[0115] 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.

[0116] 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 the 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. However, the alkali-soluble polysaccharide content of chemically modified cellulose fibers may not be accurately calculated due to the presence of chemical modification groups. In this case, the average alkali-soluble polysaccharide content of the cellulose fiber immediately before chemical modification, or the raw material for the cellulose fiber immediately before chemical modification, may be considered as the average alkali-soluble polysaccharide content of the chemically modified cellulose fiber.

[0117] 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.

[0118] 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.

[0119] 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 number average of the acid-insoluble component content calculated for three samples is taken as the average acid-insoluble component content. In the case of chemically modified cellulose fibers, it may not be possible to accurately calculate the average acid-insoluble component content due to the presence of chemical modification groups. In this case, the average alkali-soluble polysaccharide content of the cellulose fiber immediately before chemical modification, or the raw material for the cellulose fiber immediately before chemical modification, may be considered as the average alkali-soluble polysaccharide content of the chemically modified cellulose fiber.

[0120] [Thermal decomposition onset temperature (T D )] The thermal decomposition onset temperature of cellulose fibers (T D In one embodiment, the thermal decomposition start 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, from the viewpoint of avoiding thermal degradation during melt kneading and being able to exhibit mechanical strength. A higher thermal decomposition start 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.

[0121] [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.

[0122] 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 concentration 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.

[0123] In this disclosure, T DThis 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 heating 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 heating 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 at which a 1 wt% weight loss occurs (T 1% ) and temperature (T) when weight decreases by 2 wt% 2% Obtain a straight line passing through ( ). The temperature at the point where this 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.

[0124] 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.

[0125] Weight loss rate of cellulose fibers at 250°C (T 250℃ ) is the weight loss rate when cellulose fibers are held at 250°C under a nitrogen flow for 2 hours in 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 being held at 250°C for 2 hours is taken as W1, which is calculated using the following formula. Weight change rate at 250℃ (%): (W1-W0) / W0×100

[0126] [Porous Sheet] The 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% , T 250℃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.

[0127] 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 (e.g., a high-shear homogenizer (e.g., IKA, 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. 2 Materials with a density of 100 sec / 100 ml or less are treated as porous sheets and used as measurement samples.

[0128] The air permeability resistance R was measured by measuring 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 area. Weight: 10g / m 2 Air permeability resistance (sec / 100ml) = R / W × 10

[0129] [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, TD , 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.

[0130] [Chemical modification] Cellulose fibers may be chemically modified cellulose fibers (also called chemically modified cellulose fibers). Cellulose fibers may be chemically modified beforehand, for example, at the stage of cellulose fiber raw material, during defibration treatment, or after defibration treatment, or they may be chemically modified during or after the preparation of slurry as a dispersion, or during or after the drying and granulation process. Chemically modified cellulose fibers can, in one embodiment, have excellent heat resistance. High heat resistance can be advantageous when kneading with polyamides (e.g., polyamide 66, polyamide 9T, etc.) which have relatively high processing temperatures.

[0131] As a modifying agent for cellulose fibers, compounds that react with the hydroxyl groups of cellulose can be used, such as esterifying agents, etherifying agents, and silylating agents. In a preferred embodiment, the chemical modification is acylation using an esterifying agent, and particularly preferably acetylation. As esterifying agents, acid halides, acid anhydrides, vinyl carboxylates, and carboxylic acids are preferred.

[0132] The acid halide may be at least one compound selected from the group consisting of compounds represented by the following formula.

[0133] R 1 -C(=O)-X (In the formula, R 1(where X represents an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, a cycloalkyl group having 3 to 24 carbon atoms, or an aryl group having 6 to 24 carbon atoms, and X is Cl, Br, or I.) Specific examples of acid halides include, but are not limited to, acetyl chloride, acetyl bromide, acetyl iodide, propionyl chloride, propionyl bromide, propionyl iodide, butyryl chloride, butyryl bromide, butyryl iodide, benzoyl chloride, benzoyl bromide, and benzoyl iodide. Among these, acid chlorides are particularly suitable due to their reactivity and ease of handling. In the reaction of acid halides, one or more alkaline compounds may be added to act as a catalyst and to neutralize the acidic by-products. Specific examples of alkaline compounds include, but are not limited to, tertiary amine compounds such as triethylamine and trimethylamine; and nitrogen-containing aromatic compounds such as pyridine and dimethylaminopyridine.

[0134] Any suitable acid anhydride can be used as the acid anhydride. For example, Saturated aliphatic monocarboxylic acid anhydrides such as acetic acid, propionic acid, (iso)butyric acid, and valeric acid; unsaturated aliphatic monocarboxylic acid anhydrides such as (meth)acrylic acid and oleic acid; Alicyclic monocarboxylic acid anhydrides such as cyclohexanecarboxylic acid and tetrahydrobenzoic acid; Aromatic monocarboxylic anhydrides such as benzoic acid and 4-methylbenzoic acid; Examples of dibasic carboxylic acid anhydrides include saturated aliphatic dicarboxylic anhydrides such as succinic anhydride and adipic acid, unsaturated aliphatic dicarboxylic anhydrides such as maleic anhydride and itaconic anhydride, alicyclic dicarboxylic anhydrides such as 1-cyclohexene-1,2-dicarboxylic anhydride, hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride, and aromatic dicarboxylic anhydrides such as phthalic anhydride and naphthalic anhydride; Examples of polybasic carboxylic acid anhydrides with three or more bases include (anhydride) polycarboxylic acids such as trimellitic anhydride and pyromellitic anhydride.

[0135] Furthermore, in the reaction of acid anhydrides, one or more acidic compounds such as sulfuric acid, hydrochloric acid, or phosphoric acid, or Lewis acids (for example, Lewis acid compounds represented as MYn, where M represents a metalloid element such as B, As, or Ge, or a base metal element such as Al, Bi, or In, or a transition metal element such as Ti, Zn, or Cu, or a lanthanide element; n is an integer corresponding to the valence of M, representing 2 or 3; and Y represents a halogen atom, OAc, OCOCF3, ClO4, SbF6, PF6, or OSO2CF3(OTf)), or alkaline compounds such as triethylamine or pyridine may be added as catalysts.

[0136] Examples of vinyl carboxylates include those with the following formula: R-COO-CH=CH2 A vinyl carboxylate ester represented by the formula {wherein R is any of an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, a cycloalkyl group having 3 to 16 carbon atoms, or an aryl group having 6 to 24 carbon atoms} is preferred. The vinyl carboxylate ester is more preferably at least one selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl cyclohexanecarboxylate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl pivalate, vinyl octoate, divinyl adipate, vinyl methacrylate, vinyl crotate, vinyl octoate, vinyl benzoate, and vinyl cinnamate. In esterification reactions with vinyl carboxylates, one or more catalysts selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal bicarbonates, primary to tertiary amines, quaternary ammonium salts, imidazoles and their derivatives, pyridines and their derivatives, and alkoxides may be added.

[0137] Examples of alkali metal hydroxides and alkaline earth metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and barium hydroxide. Examples of alkali metal carbonates, alkaline earth metal carbonates, and alkali metal bicarbonates include lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, and cesium bicarbonate.

[0138] Primary, secondary, and tertiary amines refer to primary, secondary, and tertiary amines, and specific examples include ethylenediamine, diethylamine, proline, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,3-propanediamine, N,N,N',N'-tetramethyl-1,6-hexanediamine, tris(3-dimethylaminopropyl)amine, N,N-dimethylcyclohexylamine, and triethylamine.

[0139] Examples of imidazoles and their derivatives include 1-methylimidazole, 3-aminopropylimidazole, and carbonyldiimidazole.

[0140] Examples of pyridine and its derivatives include N,N-dimethyl-4-aminopyridine and picoline.

[0141] Examples of alkoxides include sodium methoxide, sodium ethoxide, and potassium t-butoxide.

[0142] The carboxylic acid is selected from the group consisting of compounds represented by the following formula.

[0143] R-COOH (In the formula, R represents an alkyl group having 1 to 16 carbon atoms, an alkenyl group having 2 to 16 carbon atoms, a cycloalkyl group having 3 to 16 carbon atoms, or an aryl group having 6 to 16 carbon atoms.)

[0144] Specific examples of carboxylic acids include at least one selected from the group consisting of acetic acid, propionic acid, butyric acid, caproic acid, cyclohexanecarboxylic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, pivalic acid, methacrylic acid, crotonic acid, octic acid, benzoic acid, and cinnamic acid.

[0145] Among these carboxylic acids, at least one selected from the group consisting of acetic acid, propionic acid, and butyric acid, particularly acetic acid, is preferred from the viewpoint of reaction efficiency.

[0146] Furthermore, in the reaction of carboxylic acids, one or more acidic compounds such as sulfuric acid, hydrochloric acid, or phosphoric acid, or Lewis acids (for example, Lewis acid compounds represented as MYn, where M represents a metalloid element such as B, As, or Ge, or a base metal element such as Al, Bi, or In, or a transition metal element such as Ti, Zn, or Cu, or a lanthanide element; n is an integer corresponding to the valence of M, representing 2 or 3; and Y represents a halogen atom, OAc, OCOCF3, ClO4, SbF6, PF6, or OSO2CF3(OTf)), or alkaline compounds such as triethylamine or pyridine may be added as catalysts.

[0147] Among these esterification reagents, at least one selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, vinyl acetate, vinyl propionate, vinyl butyrate, and acetic acid, with acetic anhydride and vinyl acetate being particularly preferred from the viewpoint of reaction efficiency.

[0148] [Degree of acyl substitution (DS)] When cellulose fibers are chemically modified (e.g., by hydrophobization such as acylation), they tend to disperse well in elastomers. However, the cellulose fibers of this disclosure, when combined with a dispersant, can exhibit good dispersibility in elastomers even if they are unsubstituted or have a low degree of substitution. When the cellulose fibers are esterified cellulose fibers, the degree of acyl substitution (DS) is preferably 0.1 or higher, or 0.2 or higher, or 0.25 or higher, or 0.3 or higher, or 0.5 or higher, in order to obtain esterified cellulose fibers with a high thermal decomposition onset temperature. Furthermore, since an unmodified cellulose skeleton remains in the esterified cellulose fibers, the degree of acyl substitution (DS) is preferably 2.0 or lower, or 1.8 or lower, or 1.5 or lower, or 1.2 or lower, or 1.0 or lower, or 0.8 or lower, or 0.7 or lower, or 0.6 or lower, or 0.5 or lower, in order to obtain esterified cellulose fibers that combine high tensile strength and dimensional stability derived from cellulose with a high thermal decomposition onset temperature derived from chemical modification.

[0149] The degree of acyl substitution (DS) of chemically modified cellulose fibers, when the modifying group is an acyl group, can be calculated from the reflectance infrared absorption spectrum of the esterified cellulose fiber based on the peak intensity ratio between the peak derived from the acyl group and the peak derived from the cellulose skeleton. The peak of the C=O absorption band based on the acyl group is at 1730 cm⁻¹. -1 The peak of the CO absorption band based on the cellulose backbone chain appears at 1030 cm⁻¹. -1 It appears in [location]. The DS of esterified cellulose fibers is obtained by creating a correlation graph between the DS obtained from solid-state NMR measurements of esterified cellulose fibers (described later) and the modification rate (IR index 1030), which is defined as the ratio of the peak intensity of the absorption band of C=O based on the acyl group to the peak intensity of the absorption band of CO in the cellulose backbone chain, and a calibration curve calculated from the correlation graph. Degree of substitution DS = 4.13 × IR index (1030) This can be obtained by using [this method].

[0150] The method for calculating the DS of esterified cellulose fibers using solid-state NMR is as follows: For freeze-pulverized esterified cellulose fibers...13 The following formula can be used to determine the signal intensity (Inf) from a single carbon atom derived from the modifying group, based on the total area intensity (Inp) of the signals attributed to carbon atoms C1-C6 derived from the pyranose ring of cellulose, which appear in the range of 50 ppm to 110 ppm. DS = (Inf) × 6 / (Inp) For example, if the modifying group is an acetyl group, you can use the 23 ppm signal assigned to -CH3.

[0151] Use 13 The conditions for 13C solid-state NMR measurement are as follows, for example: Equipment:Bruker Biospin Avance500WB Frequency: 125.77MHz Measurement method: DD / MAS method Waiting time: 75 seconds NMR sample tube: 4mmφ Total number of times: 640 (approximately 14 hours) MAS: 14,500Hz Chemical shift reference: Glycine (External reference: 176.03 ppm)

[0152] The DS non-uniformity ratio (DSs / DSt), defined as the ratio of the degree of modification of the fiber surface (DSs) to the degree of modification of the entire fiber (DSt) (which is synonymous with the degree of acyl substitution (DS) above) of chemically modified cellulose fibers, is preferably 1.05 or higher. The larger the value of the DS non-uniformity ratio, the more pronounced the sheath-core-like non-uniform structure (i.e., a structure in which the fiber surface is highly chemically modified while the fiber core retains a structure close to the original unmodified cellulose), which allows for improved affinity with elastomers when compounded with elastomers, and improved dimensional stability of thermoplastic elastomer resin compositions, while maintaining high tensile strength and dimensional stability derived from cellulose. The DS non-uniformity ratio is more preferably 1.1 or higher, or 1.2 or higher, or 1.3 or higher, or 1.5 or higher, or 2 or higher, and from the viewpoint of ease of manufacturing chemically modified cellulose fibers, it is preferably 30 or lower, or 20 or lower, or 10 or lower, or 6 or lower, or 4 or lower, or 3 or lower.

[0153] The value of DSs varies depending on the degree of modification of the esterified cellulose fiber, but as an example, it is preferably 0.1 or higher, more preferably 0.2 or higher, even more preferably 0.3 or higher, even more preferably 0.5 or higher, preferably 3.0 or lower, more preferably 2.5 or lower, particularly preferably 2.0 or lower, even more preferably 1.5 or lower, particularly preferably 1.2 or lower, and most preferably 1.0 or lower. The preferred range for DSt is as described above for acyl substituents (DS).

[0154] A smaller coefficient of variation (CV) of the DS heterogeneity ratio of chemically modified cellulose fibers is preferable because it reduces the variation in various physical properties of the 3D printing material. Preferably, the coefficient of variation is 50% or less, or 40% or less, or 30% or less, or 20% or less. The coefficient of variation can be further reduced in a method in which chemical modification is performed after defibrillation of the cellulose fiber raw material (i.e., sequential method), while it can be increased in a method in which defibrillation and chemical modification of the cellulose fiber raw material are performed simultaneously (i.e., simultaneous method). Although the mechanism of action is not clear, it is thought that in the simultaneous method, chemical modification proceeds more easily in the thin fibers generated in the initial stages of defibrillation, and as the hydrogen bonds between cellulose microfibrils decrease due to chemical modification, defibrillation proceeds further, resulting in an increase in the coefficient of variation of the DS heterogeneity ratio.

[0155] The coefficient of variation (CV) of the DS heterogeneity ratio can be calculated using the following formula: 100g of an aqueous dispersion of chemically modified cellulose fibers (solid content of 10% by mass or more) is taken, frozen and ground into 10g portions, and the DS heterogeneity ratio is calculated from the DSt and DSs of 10 samples. Then, the standard deviation (σ) and arithmetic mean (μ) of the DS heterogeneity ratios among the 10 samples are used.

[0156] DS heterogeneity ratio = DSs / DSt Coefficient of variation (%) = Standard deviation σ / Arithmetic mean μ × 100

[0157] The method for calculating DSs is as follows: Esterified cellulose fibers, powdered by freeze-grinding, are placed on a 2.5 mmφ dish-shaped sample stage, the surface is pressed down to flatten it, and measurement is performed by X-ray photoelectron spectroscopy (XPS). The XPS spectrum reflects the constituent elements and chemical bonding state of only the surface layer of the sample (typically a few nm). Peak separation is performed on the obtained C1s spectrum, and the area intensity (Ixp) of the peak attributed to a single carbon atom derived from the modifying group is used to determine the DSs using the following formula, compared to the area intensity (Ixf) of the peak attributed to a single carbon atom derived from the pyranose ring of cellulose (289 eV, CC bond). DSs = (Ixf) × 5 / (Ixp) For example, if the modifying group is an acetyl group, after separating the C1s spectrum at 285eV, 286eV, 288eV, and 289eV, the 289eV peak can be used for Ixp and the peak derived from the OC=O bond of the acetyl group (286eV) can be used for Ixf.

[0158] The conditions used for XPS measurement are as follows, for example: Equipment used: ULVAC-FI VersaProbeII Excitation source: mono.AlKα 15kV × 3.33mA Analysis size: Approximately 200 μmφ Photoelectron extraction angle: 45° Capture area Narrow scan: C 1s, O 1s Pass Energy: 23.5 eV

[0159] 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.

[0160] <Other ingredients> The thermoplastic elastomer resin composition of this embodiment may contain, in addition to the thermoplastic elastomer and cellulose fibers described above, 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, flow improvers, and mold release agents.

[0161] [Coloring agent] Examples of the above-mentioned 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, and phthalocyanine blue.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] [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.

[0166] 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. When the vial is filled to a height of 1 mm with the liquid polymer and sealed, and the vial is left upside down for 24 hours, a movement of 0.1 mm or more of the substance in the vertical direction can be observed.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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. It is 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 the liquid polymer.

[0171] 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 stably obtained, 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] (Conjugated diene polymers) The conjugated diene polymer may be a homopolymer, or a copolymer of two or more conjugated diene monomers, or a copolymer of a conjugated diene monomer and another monomer. The copolymer may be random or block-shaped.

[0176] 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.

[0177] 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 a conjugated diene monomer. 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 article, styrene is preferred.

[0178] Examples of random copolymers include butadiene-isoprene random copolymers, 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.

[0179] A block copolymer may be a copolymer consisting of two or more blocks. For example, a block copolymer may have a structure such as AB, ABA, or ABAB, 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 between 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 tapered. Furthermore, block B may have multiple portions where the aromatic vinyl monomer is uniformly distributed and / or tapered. 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.

[0180] 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.

[0181] In conjugated diene polymers, the amount of vinyl bonds in the conjugated diene bond units (e.g., 1,2- or 3,4- bonds of butadiene) is preferably 10 mol% or more and 75 mol% or less, or 13 mol% or more and 65 mol% or less. The amount of vinyl bonds in a conjugated diene bond unit (e.g., the amount of 1,2-bonds in butadiene) can be determined by 13C-NMR (quantitative mode). Specifically, by integrating the peak areas that appear 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

[0182] 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 be preferably 5 mol% to 70 mol%, or 10 mol% to 50 mol%, based on 100% of the total moles of the conjugated diene polymer.

[0183] Examples of hydrogenated conjugated diene polymers include those exemplified above, such as hydrogenated butadiene homopolymers, isoprene homopolymers, styrene-butadiene copolymers, and acrylonitrile-butadiene copolymers.

[0184] 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).

[0185] (Non-conjugated diene polymers) The non-conjugated diene polymer may be a homopolymer, or a copolymer of two or more non-conjugated diene monomers, or a copolymer of a non-conjugated diene monomer and another monomer. The copolymer may be random or block. Examples of non-conjugated diene polymers include olefin polymers (e.g., liquid paraffin), silicone polymers, and acrylic polymers. For example, when the liquid polymer is liquid rubber, the non-conjugated diene polymer may be: Olefin polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, and ethylene-α-olefin copolymers. Examples include 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, and polysulfide rubber.

[0186] 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.

[0187] 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.

[0188] 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 a gel permeation chromatography analyzer using 1,2,4-trichlorobenzene as a solvent at 140°C with a polystyrene standard.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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, and preferably 50 mPa·s or more, or 100 mPa·s or more, or 300 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.

[0195] 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.

[0196] 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.

[0197] The viscosity of the liquid polymer is measured using a Type B viscometer at a rotation speed of 10 rpm.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] [Dispersant] In one embodiment, the thermoplastic elastomer resin composition includes a dispersant. In one embodiment, it is even more preferable, from the viewpoint of more uniformly dispersing cellulose fibers in the thermoplastic elastomer resin composition, that the dispersant has a hydrophilic segment and a hydrophobic segment within the same molecule (i.e., is an amphiphilic molecule). In a preferred embodiment, the thermoplastic elastomer resin composition includes a polyoxyethylene unit-containing polymer.

[0202] (Amphipathic component) 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), and primary to tertiary amines and quaternary ammonium salts. The counteranions of the above quaternary ammonium salts 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, hexafluorophosphate, and tetrafluoroborate.

[0203] 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. While longer chain lengths increase affinity with cellulose fibers, from the viewpoint of balancing this with 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.

[0204] Examples of hydrophobic segments include segments containing hydrocarbons, segments containing fluorinated carbon, 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 type, alkenyl type, alkyl ether type, alkenyl ether type, alkylphenyl ether type, alkenylphenyl ether type, rosin ester type, bisphenol A type, β-naphthyl type, styrene-phenyl type, and hydrogenated castor oil type. 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. As for the segment having fluorinated carbon, linear or branched alkyl types with 1 to 20 carbon atoms are preferred. Preferred polymer structures 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, phenolic resins, and the like. 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.

[0205] 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-shaped 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, their molecular structure may be a single type or a combination of two or more types. Similarly, when multiple hydrophobic segments are present in a molecule, their molecular structure may be a single type or a combination of two or more types.

[0206] (Surfactants) Any of the following can be used as the amphiphilic molecule: anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. The dispersant may be a polymeric surfactant, a reactive surfactant, or the like.

[0207] 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 monolaurate, sorbitan monostearate), and polyoxyethylene-polyoxypropylene block polymers.

[0208] 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.

[0209] Cationic surfactants include amine salts, amidoamine salts, quaternary ammonium salts, and imidazolinium salts. Specific examples, though not particularly limited, 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.

[0210] 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.

[0211] (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 can be 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. Among these, cellulose derivatives and polyalkylene glycols are more preferred, and polyalkylene glycols are particularly preferred.

[0212] The amount of the 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 the cellulose fiber, and is 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.

[0213] In one aspect, the content of the dispersant in the thermoplastic elastomer resin composition component may be 0.1% by mass or more, or 0.5% by mass or more, or 1% by mass or more, and in one aspect, may be 40% by mass or less, or 35% by mass or less, or 30% by mass or less.

[0214] For example, when a preliminary composition containing cellulose fiber and an acid-modified styrene-based elastomer is used in the production of the thermoplastic elastomer resin composition, the mass ratio (preliminary composition / thermoplastic elastomer (styrene-based elastomer in one aspect)) between the preliminary composition and the thermoplastic elastomer other than the acid-modified styrene-based elastomer in the thermoplastic elastomer resin composition component may 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 in one aspect.

[0215] [Vulcanizing agent, vulcanization accelerator] When the thermoplastic elastomer resin composition component contains a liquid rubber, the thermoplastic elastomer resin composition component typically contains a vulcanizing agent and may optionally contain a vulcanization accelerator. As the vulcanizing agent and the vulcanization accelerator, conventionally known ones may be appropriately selected according to the type of the liquid rubber in the thermoplastic elastomer resin composition component. As the vulcanizing agent, organic peroxides, azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, sulfur compounds, etc. can be used. Examples of the sulfur compound include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular polysulfur compounds, etc.

[0216] The amount of the vulcanizing agent in the thermoplastic elastomer resin composition component is preferably 0.01 to 20 parts by mass, or 0.1 to 15 parts by mass, based on 100 parts by mass of the liquid rubber in the thermoplastic elastomer resin composition component.

[0217] Examples of the vulcanization accelerator include vulcanization accelerators such as sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based. Zinc oxide, stearic acid, etc. may be used as the vulcanization aid. The amount of the vulcanization accelerator is preferably 0.01 to 20 parts by mass, or 0.1 to 15 parts by mass, based on 100 parts by mass of the liquid rubber in the thermoplastic elastomer resin composition component.

[0218] [Additives for rubber] The thermoplastic elastomer resin composition component may contain various conventionally known additives for rubber (stabilizers, softeners, anti-aging agents, etc.). As the rubber stabilizer, one or more antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol may be used. Also, as the rubber softener, one or more of process oil, extender oil, etc. may be used. However, the thermoplastic elastomer resin composition of the present embodiment can form a flexible molded body in one aspect, and thus the thermoplastic elastomer resin composition component can contain no rubber softener in one aspect.

[0219] Note that the vulcanizing agent, vulcanization accelerator, and additives for rubber are typically added during the production of the thermoplastic elastomer resin composition, but the mode of addition is not limited thereto.

[0220] [Shape of thermoplastic elastomer resin composition] The thermoplastic elastomer resin composition of this embodiment can be provided in various shapes. Specifically, these include filament shape, powder shape, pellet shape, plate shape, etc., but filament shape and pellet shape are preferred due to their ease of manufacturing.

[0221] 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 have the following relationship: -9 ≤ (D1 - D2) / D2 × 100 ≤ 0 0 ≤ (D3 - D2) / D2 × 100 ≤ 9 The following conditions are satisfied. 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.

[0222] 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 level of detail. In one embodiment, the length of the filament material may be 20,000 m or less.

[0223] The arithmetic mean roughness Ra of the filamentous material is preferably 10 or higher, or 20 or higher, or 30 or higher, or 40 or higher. When the surface roughness of the filamentous material is within this range, it is easier to pull the filament from the reel. From the viewpoint of dimensional accuracy of the molded object, the arithmetic mean roughness Ra may be 200 or lower, or 150 or lower. 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.

[0224] 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. 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.

[0225] Pellet-shaped materials can take various forms, including 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 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.

[0226] 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 (e.g., 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, 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 MalvernPanalytical.

[0227] In one embodiment, the powdered material can be produced by pulverizing or reprecipitating a thermoplastic elastomer resin composition. The method of pulverizing the thermoplastic elastomer resin composition is not particularly limited, but may include wet pulverization, dry pulverization, low-temperature pulverization, freeze pulverization, and heat pulverization. A pulverizing medium (e.g., stainless steel balls, ceramic balls, plastic balls, glass beads, gravel) may be used to control the shape of the powdered material.

[0228] <Manufacturing of thermoplastic elastomer resin compositions> Thermoplastic elastomer resin compositions may be produced by heating and kneading a mixture containing thermoplastic elastomer raw materials and optionally other components such as cellulose fibers. The raw materials for thermoplastic elastomer resin compositions 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.

[0229] 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.

[0230] <<Shaped objects and methods for manufacturing them>> One aspect of the present invention also provides a molded object obtained using the thermoplastic elastomer resin composition of the present disclosure, and a method for manufacturing the same. In one aspect, the molded object is an additive product of the thermoplastic elastomer resin composition. In one aspect, a molded object, which is a three-dimensional object, can be manufactured by processing (specifically molding) the thermoplastic elastomer resin composition using a 3D printer. A method for manufacturing a molded object according to one aspect includes extruding the thermoplastic elastomer resin composition from the nozzle of a 3D printer and performing additive manufacturing. 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.

[0231] In a method for manufacturing a molded object according to one embodiment, the molding pitch coefficient, which is the ratio of the layer pitch P to the nozzle diameter D of the nozzle (P / D), is 0.05 or more and less than 0.5. In one embodiment, the molding pitch coefficient may be less than 0.5, or 0.40 or less, or 0.38 or less, and in one embodiment, it may be 0.05 or more, or 0.10 or more, or 0.15 or more.

[0232] In one embodiment, the actual dimensions of the molded object in the width or thickness direction are within ±10% of the set dimensions in the 3D printer. In this case, the molded object can be said to be constructed with a layering pitch of at least Pmin, the minimum buildable layering pitch in this disclosure, and at least Pmax, the maximum buildable layering pitch in this disclosure. From the viewpoint of excellent moldability, in the method for manufacturing a molded object according to one embodiment, it is preferable that the actual dimensions of the molded object in the width or thickness direction are within ±10% of the set dimensions in the 3D printer, and more preferably within ±8%, ±5%, or ±3%. In this disclosure, the width direction of the molded object is the direction perpendicular to the layering pitch in the molded object itself, and the thickness direction of the molded object is the layering pitch direction in the molded object itself. In one embodiment, the width direction is the direction in which the largest amount of molding material is formed by volume, among the longitudinal directions of each layer in the laminate. While a smaller difference between the actual dimensions and the set dimensions is advantageous, from the viewpoint of ease of manufacturing the molded object, in one embodiment, the actual dimensions may be ±0.05% or more of the set dimensions. In one embodiment, in the thickness direction of the molded object, the actual dimensions may be within ±10%, ±8%, ±5%, or ±3% of the set dimensions, and may be ±0.05% or more. In one embodiment, in both the width direction and the thickness direction of the molded object, the actual dimensions may be within ±10%, ±8%, ±5%, or ±3% of the set dimensions, and may be ±0.05% or more.

[0233] 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 by cutting a 200 mm × 10 mm × 2 mm test piece from the molded object and pressing down on one end in the long side direction for 10 mm, and measuring the amount of lift at the other end in the long side direction. In one aspect, the amount of warpage measured by the above method for a test piece formed from the thermoplastic elastomer resin composition in accordance with the procedure described in the [Examples] section to a length of 200 mm × width of 10 mm × thickness of 2 mm may be within the above range.

[0234] In one aspect, the surface roughness ratio of a shaped article obtained using the 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 viewpoints of improving the assembly property with other materials, improving the sliding property, facilitating subsequent processes, and the physical properties of the shaped article. When the surface roughness ratio of the shaped article becomes excessively large, large bumps or swellings are observed on the surface of the shaped article. When the surface roughness ratio of the shaped article becomes excessively small, large gaps are observed between the shaping pass lines on the surface of the shaped article.

[0235] The surface roughness ratio of the shaped article 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.

[0236] The surface roughness ratio of the present disclosure is the number average value of 10 points when calculated based on JIS B0601:2013, with the evaluation length being 4 mm, measuring 10 times, and dividing the number of peaks where R is less than -10 by 4. In one aspect, the surface roughness ratio measured by the above method for a test piece formed from the thermoplastic elastomer resin composition in accordance with the procedure described in the [Examples] section to a length of 200 mm × width of 10 mm × thickness of 2 mm may be within the above range.

[0237] In one aspect, the shrinkage rate of a shaped article obtained using the thermoplastic elastomer resin composition is preferably 20% or less, or 15% or less, or 10% or less, and more preferably 5% or less, from the viewpoints of improving dimensional accuracy, improving the assembly property with other materials, and improving 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 specimen prepared by molding a thermoplastic elastomer resin composition in the [Examples] section using the procedure described therein, with dimensions of 200 mm in length, 200 mm in width, 20 mm in height, and 1 mm in wall thickness, the shrinkage rate calculated using the following formula with respect to the length L (mm) of the obtained test specimen may be within the above range. (Shrinkage rate) = (1 - L / 200) × 100

[0238] (Applications of thermoplastic elastomer resin compositions and molded objects) The thermoplastic elastomer resin composition of this embodiment and the 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; 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; dampers; factory equipment such as cushioning materials for air conditioning outlets, bonding cushioning materials, and heat insulating protective members; parts for multifunction printers; smartphone accessories, etc.

[0239] 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.

[0240] Specifically, this includes the steering shaft, mounts, sunroof, steps, 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, onboard 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.

[0241] Panels, floor panels, exterior panels, doors, cabin, roof, hood, valves, EGR (Exhaust Gas Recirculation) valves, variable valve timing units, 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), tunnels, fastening inserts, crash boxes, crash rails, corrugated panels, roof rails, upper body, side rails, braiding, door surround assemblies, 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,

[0242] 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 an arm (suspension, lower, hood hinge), armrest, suspension link, impact absorption bracket, fender bracket, inverter bracket, inverter module, hood inner panel, hood panel, cowl louvers, cowl top outer front panel, cowl top outer panel, floor silencer, dump sheet, hood insulator, fender side panel protector, cowl insulator, cowl top ventilator louver, cylinder head cover, tire deflector, fender support, strut tower bar, transmission center tunnel, floor tunnel, radiator core support, luggage panel, luggage floor, accelerator pedal, accelerator pedal base, etc.

[0243] 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. [Examples]

[0244] 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.

[0245] 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.

[0246] ≪Evaluation Method≫ <Thermoplastic elastomer> [MFR at 230℃, 2.16kg] The values ​​shown are from the product catalog.

[0247] [hardness] Two test specimens (ISO 37 type 3), manufactured 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 using a hardness tester (DM-204A; Muratec KDS Corporation) in accordance with ISO 7619.

[0248] [Viscosity at 280°C] Measurements were taken using a tabletop 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.

[0249] <Cellulose fiber> [Average fiber length of CNF-A] The concentrated 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 major axis of 100 randomly selected cellulose fibers was measured, and the average of the 100 cellulose fibers was calculated.

[0250] <Cellulose fibers included 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. The average fiber length of the fibers in the top 10% of the obtained fibers was defined 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.

[0251] (Processing by 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 > Threshold (Triangle)) 5. 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 Treshold:0.00, Upper Treshold:0.17, Minimum Line Length:20, Maximum Line Length:0.00)

[0252] <Thermoplastic elastomer resin composition> [Shore A hardness] Two test specimens (ISO 37 type 3), manufactured 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 using a hardness tester (DM-204A; Muratec KDS Corporation) in accordance with ISO 7619.

[0253] [Maximum build pitch coefficient] Using a 3D printer (Raise3D pro3, manufactured by Raise3D), strip-shaped test specimens measuring 80 mm in length, 10 mm in width, and 4 mm in thickness were fabricated under the conditions described in each example: ambient temperature of 23°C, nozzle diameter of 0.8 mm, and nozzle and bed temperatures. 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 and 10 mm wide. All layers were layered in the thickness direction of the strip-shaped test specimen, with the nozzle moved so that the direction along the 80 mm long x 10 mm outer circumference was the longitudinal direction of each layer. The first two layers from the top and the first two layers from the bottom were layered at 45° and 135° angles to the longitudinal direction of the test specimen, respectively, while the remaining layers were layered 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). Printing was performed with layer thicknesses of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm. Printing was considered successful if the resulting object had a width of 9 to 11 mm (i.e., within ±10% of the design dimension in the width direction) and a thickness of 3.6 to 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 maximum successful layer thickness was divided by the nozzle diameter of 0.8 mm to determine the maximum printing pitch coefficient.

[0254] [Minimum build pitch coefficient] Using a 3D printer (Raise3D pro3, manufactured by Raise3D), strip-shaped test specimens measuring 80 mm in length, 10 mm in width, and 4 mm in thickness were fabricated under the conditions described for each example: ambient temperature of 23°C, nozzle diameter of 0.8 mm, and nozzle and bed temperatures. The layer thickness direction was the same as the thickness direction of the strip-shaped test specimen. The outer two layers of all layers were fabricated in a direction 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. Fabrication was performed by increasing the layer thickness from 0.01 mm in increments of 0.01 mm. If the fabricated object was within the range of width 9-11 mm and thickness 3.6-4.4 mm, it was considered a successful fabrication; if it was outside this range, it was considered a failure. The minimum fabrication pitch coefficient was calculated by dividing the minimum successful layer thickness by the nozzle diameter of 0.8 mm.

[0255] [Modulus of elasticity at 15% elongation] A dumbbell-shaped test specimen (No. 3) conforming to JIS K6251 was prepared using an injection molding machine (EC5P, manufactured by Shibaura Machine Co., Ltd.). A tensile test was performed with an air chuck pressure of 0.25 MPa and a tensile speed of 50 mm / min. The stress at which the gauge length was elongated by 15% was defined as the 15% elongation modulus of the thermoplastic elastomer resin composition.

[0256] [Viscosity at 280°C] Measurements were taken using a tabletop 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.

[0257] [Water absorption rate] Using the thermoplastic elastomer resin compositions prepared in the examples and comparative examples described later, the moisture content (ppm) in the pellets was measured using a Karl Fischer moisture meter (Mitsubishi Chemical Analytec Coulometric Titration Type Trace Moisture Analyzer CA-200) in accordance with ISO 15512.

[0258] [Porosity] 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 then determining the ratio of the void area to the cross-sectional area of ​​the thermoplastic elastomer resin composition from the obtained image. The void area was determined using ImageJ following the procedure below. 1. Select an area along the outline of the filament, then use Analyze → Measure to find the area of ​​the filament cross-section. 2. Use Edit → Clear Outside to erase everything except the filament cross-section. 3. Adjust the hue using Image → Adjust → Color Balance. At this time, move the Brightness bar all the way to the right, move the Maximum bar to the left of the tail of the histogram peak, and align it exactly with the tail of the histogram peak. 4. Go to Image → Color → Split Channels to separate the image into RGB channels, and close all windows except for Red. 5. Define it in black and white using Process → Binary → Make Binary. 6. Use Analyze Particles to find the area of ​​the black dots as the area of ​​the void. The void ratio is calculated by dividing the area of ​​the void obtained in 7.6 by the area of ​​the filament cross-section obtained in 1.

[0259] [Variation in filament diameter] The wire diameter was measured by passing a 10m length of filament wound on a spool through a wire diameter measuring instrument (LS-9006MR, LS-9006MT, KEYENCE Corporation) at a speed of 1m / min. The sampling interval was 5 points / second. The maximum, minimum, and average values ​​of the obtained wire diameters were determined. Additionally, the variation in 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).

[0260] [Amount of aggregated material] 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.

[0261] [Meltmass Flow Rate (MFR)] The MFR of the thermoplastic elastomer resin composition in each example was measured in accordance with ISO 1133, at the same nozzle temperature as described in each example, under a load of 2.16 kg.

[0262] <Formability during molding> [Adhesion to build plate] Using the thermoplastic elastomer resin compositions prepared in each example, rectangular parallelepipeds with a length of 50 mm, a width of 50 mm, and a height of 5 mm were fabricated using a 3D printer. The layer thickness direction was the height direction. A circle (○) was used to indicate excellent adhesion to the build plate if no peeling was observed during fabrication, and a circle (×) was used if peeling was observed.

[0263] [Holes in the structure] 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 layer thickness direction was the height direction. The number of holes formed on the side surface of the fabricated object was counted, and objects with fewer holes were evaluated as having better fabricability.

[0264] [Building 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 fabricated using a 3D printer. The layer thickness direction was the height direction. The cube consisted of a total of 250 layers. During this process, the number of times the filament clogged the nozzle was measured. A lower number of clogs indicated superior fabrication stability.

[0265] <Sculpture> [Modeling method] (Filament printing conditions) 3D printing was performed using a Raise3D Pro3 printer (manufactured by Raise3D Corporation) 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.

[0266] (Forming conditions using pellets) Using the thermoplastic elastomer resin composition pellets obtained in each example, 3D printing was performed using an 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. In each evaluation, if specific printing conditions were designated, those instructions were followed.

[0267] [Flexibility index] The hardness of the upper center of the dome shape of a fabricated 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 measured using a hardness tester (DM-204A; Muratec KDS Corporation) in accordance with ISO 7619. The hardness was then divided by the hardness of the thermoplastic elastomer resin composition.

[0268] [Shrinkage rate] Test specimens were obtained by fabricating the thermoplastic elastomer resin compositions described in each example using a frame shape with dimensions of 200 mm in length, 200 mm in width, and 20 mm in height, and a wall thickness of 1 mm. The layering pitch direction was the height direction. The longitudinal direction of each layer during fabrication was aligned with the outer circumference of all layers. The shrinkage rate was calculated using the following formula based on the length L (mm) of the obtained test specimens. (Shrinkage rate) = (1 - L / 200) × 100

[0269] [Tensile elongation] A dumbbell-shaped specimen conforming to JIS K6251, type 3, was fabricated. The layering pitch direction was the same as the thickness direction of the dumbbell specimen. Layers were stacked parallel to the longitudinal direction of the entire 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.

[0270] [Dimensional accuracy] Using the thermoplastic elastomer resin compositions prepared in each example, strip-shaped test specimens measuring 80 mm in length, 10 mm in width, and 4 mm in thickness were fabricated using a 3D printer. The layering pitch direction was the thickness direction of the strip-shaped test specimen. The outer two perimeters of all layers were fabricated in a direction along the outer perimeter, the top two layers and the bottom two layers were laid at 45° and 135° angles to the longitudinal direction of the test specimen, respectively, and the remaining layers were laid parallel to the longitudinal direction of the test specimen. The dimensional accuracy of the obtained test specimens was determined using the width W (mm) and thickness T according to the following formula. (Dimensional accuracy_width) = (1 - W / 10) × 100 (Dimensional accuracy_thickness) = (1 - T / 4) × 100

[0271] [Amount of curvature] Using the thermoplastic elastomer resin compositions prepared in each example, strip-shaped 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. The outer two perimeters of all layers were fabricated in a direction along the outer perimeter, the top two layers and the bottom two layers were laid at 45° and 135° angles to the longitudinal direction of the test specimen, respectively, and the remaining layers were laid parallel to the longitudinal direction of the test specimen. A 10 mm margin was held down from one end in the longitudinal direction, and the amount of lift at the other end in the longitudinal direction was photographed with a digital camera (Panasonic DMA-SZ10) while a ruler was applied. The amount of lift was then compared with the ruler markings in ImageJ and calculated as the amount of warping.

[0272] ≪Materials Used≫ Next, the materials used in the examples and comparative examples are as follows.

[0273] <Textiles> (Cellulose fiber) CNF-A: Three parts by mass of cotton linter pulp were immersed in 27 parts by mass of water and dispersed using a pulper. Thirty parts by mass of the pulper-treated cotton linter pulp slurry (of which three parts by mass were cotton linter pulp) were dispersed in water with 170 parts by mass of water (solid content 1.5% by mass). An SDR14 type laboratory refiner (pressure-type disk type) manufactured by Aikawa Iron Works Co., Ltd. was used as a disc refiner, and the aqueous dispersion was beaten for 30 minutes with a clearance of 1 mm between the disks. Subsequently, thorough beating was performed under conditions where the clearance was reduced to a level close to zero to obtain a beaten aqueous dispersion (solid content concentration: 1.5% by mass). The obtained beaten aqueous dispersion was then subjected to 10 micronization treatments using a high-pressure homogenizer (NSO15H manufactured by Nilo Soavi (Italy)) at an operating pressure of 100 MPa to obtain a slurry (solid content concentration: 1.5% by mass). The mixture was then concentrated to a solid content of 20% by mass using a dehydrator, yielding 15 parts by mass of concentrated CNF-A cake. The average fiber length of the obtained CNF-A was 130 μm.

[0274] (Carbon fiber) CF-A HTC413 (manufactured by Toho Tenax Co., Ltd.)

[0275] <Thermoplastic elastomer> Thermoplastic elastomer 1: SEBS (ToughTec H1052, manufactured by Asahi Kasei Corporation), MFR: 14g / 10min (230℃, 2.16kg), Shore A hardness: 60A, Viscosity at 280℃: 80g / 10min Thermoplastic elastomer 2: Maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, ToughTec M1943, MFR: 6.5g / 10min (230℃, 2.16kg), Shore A hardness: 65A, Viscosity at 280℃: 37g / 10min Thermoplastic elastomer 3: Thermoplastic polyurethane (Estrane ET680, manufactured by NTW Corporation), Shore A hardness: 80A, Viscosity at 280°C: 30g / 10min Thermoplastic elastomer 4: TPE filament (TPE60A, manufactured by Hotty Polymer Co., Ltd.), Shore A hardness: 60A, viscosity at 280°C: 120 g / min

[0276] <Thermoplastic resin> Thermoplastic resin 1: Polyamide filament (BASF PA-4501a075 (Natural))

[0277] <Dispersant> Polyethylene glycol: PEG6000, manufactured by Sanyo Chemical Industries, Ltd.

[0278] <Liquid polymer> Liquid polybutadiene: Clay Valley RICON 184, viscosity at 25°C: 75,000 mPa·s

[0279] <Antioxidant> Antioxidant: BASF Irganox 245

[0280] <filament> [Examples 1-1 to 1-6, 1-8] The CNF concentrate cake, dispersant, and liquid polymer were mixed using a planetary mixer according to the formulations shown in the table, and then dried under reduced pressure to obtain a cellulose dry product.

[0281] 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.

[0282] 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 Table 1. In Table 1, C1 to C4 are the respective zones in the extruder, and are C1, C2, C3, and C4 in order from closest to the hopper. Using the obtained filament, evaluation objects were manufactured according to the procedure described in the "Evaluation Method" section. The measurement and evaluation results for the filament and the printed objects are shown in Table 1. The filament was dried in a vacuum dryer at 80°C for 24 hours before each print.

[0283] [Examples 1-7] The procedure was the same as in Example 1-1, except that the filament was not dried before printing. The measurement and evaluation results for the filament and the printed object are shown in Table 1.

[0284] [Comparative Examples 1-1 to 1-3] The filaments listed in Table 1 were used for evaluation in the same manner as in Example 1-1. The measurement and evaluation results for the filaments and printed objects are shown in Table 1. When printing using the filament of Comparative Example 1-2, masking tape was applied to the bed before printing.

[0285] <Pellets> [Examples 2-1 to 2-8] The pellets obtained in each of Examples 1-1 to 1-8 were used as thermoplastic elastomer resin compositions. The molded objects were produced 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 with pellets.

[0286] Table 2 shows the measurement and evaluation results for the pellets and the molded objects produced using those pellets. In Examples 2-1 to 2-6 and 2-8, 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.

[0287] [Comparative Examples 2-1~2-3] The pellets listed in Table 2 were used for evaluation in the same manner as in Example 2-1. The measurement and evaluation results for the pellets and molded objects are shown in Table 2. When using the pellets of Comparative Example 2-2 for molding, masking tape was applied to the bed before molding.

[0288] [Table 1]

[0289] [Table 2]

[0290] Tables 1 and 2 show that the thermoplastic elastomer resin compositions of the embodiments according to the present invention exhibit excellent moldability when creating molded objects with low filler density or large height dimensions, and also exhibit small shrinkage of the molded objects, enabling the creation of the desired flexibility of the molded objects.

[0291] In contrast, the thermoplastic elastomer resin composition of Comparative Example 1-1 had a large maximum molding pitch coefficient of 0.5 or more. Comparative Example 1-1 had poor moldability and low flexibility. Furthermore, the molded object of Comparative Example 1-1 experienced significant shrinkage. On the other hand, the thermoplastic elastomer resin composition of Comparative Example 1-2 had a small ratio of elastic modulus to viscosity, resulting in a small maximum molding pitch coefficient and making molding impossible. In addition, the resin composition of Comparative Example 1-3 did not use a thermoplastic elastomer, resulting in low flexibility of the molded object.

[0292] Furthermore, as can be seen from Tables 1 and 2, the embodiments according to the present invention are superior to the comparative examples in terms of reducing aggregate volume, tensile elongation, and suppressing warping. [Industrial applicability]

[0293] 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 method for manufacturing a molded product which is an additive product of a thermoplastic elastomer resin composition, The method includes extruding a thermoplastic elastomer resin composition from a nozzle of a 3D printer and performing additive manufacturing. The ratio of the stacking pitch P to the nozzle diameter D of the nozzle (P / D) is 0.05 or more and less than 0.

5. A method wherein the actual dimensions of the molded object in the width or thickness direction are within ±10% of the set dimensions in the 3D printer.

2. The method according to claim 1, wherein the actual dimensions of the molded object in the width direction and thickness direction are within ±10% of the set dimensions in the 3D printer.

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

4. The method according to claim 1, wherein the thermoplastic elastomer resin composition includes an acid-modified elastomer.

5. The method according to claim 1, wherein the thermoplastic elastomer resin composition is in the form of filaments.

6. The method according to claim 1, wherein the Shore A hardness of the thermoplastic elastomer resin composition is 40A to 75A.

7. A thermoplastic elastomer resin composition for additive manufacturing, A thermoplastic elastomer resin composition in which, when the thermoplastic elastomer resin composition is extruded from the nozzle of a 3D printer and layer-formed, 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.

8. The thermoplastic elastomer resin composition according to claim 7, wherein the ratio of the minimum buildable layer thickness Pmin to the nozzle diameter D of the nozzle (Pmin / D) is 0.01 or more and 0.04 or less.

9. A thermoplastic elastomer resin composition according to claim 7, comprising a styrene-based elastomer and cellulose fibers.

10. A thermoplastic elastomer resin composition according to claim 7, comprising an acid-modified elastomer.

11. The thermoplastic elastomer resin composition according to claim 7, wherein the composition is in the form of a filament.

12. The thermoplastic elastomer resin composition according to claim 7, wherein the Shore A hardness is 40A to 75A.

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