Lignin-containing polyamide resin composition, and molded body of the same

Abstract

To provide a polyamide resin composition which enables formation of a molded body that reduces environmental load and is excellent in elastic modulus, and a molded body of the same.SOLUTION: A lignin-containing polyamide resin composition contains 10 mass% or more and 55 mass% or less of (A) glycol lignin, 40 mass% or more and 85 mass% or less of (B) a polyamide resin, and 5 mass% or more and 40 mass% or less of (C) a tabular or fibrous filler, wherein at least a part of (B) the polyamide resin contains an aliphatic skeleton.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a lignin-containing polyamide resin composition and a molded article thereof.

Background Art

[0002] In recent years, as members for automobiles, electric and electronic devices, the usage rate of lightweight plastics and those formed of composite materials containing the same has been increasing. However, the increase in the usage amount of petroleum-derived plastics not only leads to the depletion of petroleum resources, but also poses a problem of causing environmental pollution due to improper disposal of waste.

[0003] Accordingly, research on lightweight members using biomass raw materials such as lignin instead of petroleum-derived plastics has begun (see Patent Documents 1 to 3). Lignin is a component that accounts for 20 to 30% of wood, and can be obtained in large quantities from thinned wood, papermaking processes, and the like.

[0004] Patent Document 1 describes a thermoplastic resin composition comprising (A) 99 to 50% by mass of a thermoplastic resin and (B) 50 to 1% by mass of lignin acetate. The lignin acetate described in Patent Document 1 is acetylated lignin, and it is stated that by forming a composition in which this is contained in a thermoplastic resin, a composition and a molded article thereof that have reduced environmental load, high flame retardancy, and excellent appearance, heat aging resistance, and weather resistance of the molded article can be obtained.

[0005] Patent Document 2 describes a resin composition containing partially hydrolyzed fine cellulose fibers (A) and a thermoplastic resin (B) , hemicellulose (C), and lignin (D). The resin composition described in Patent Document 2 is said to provide a resin composite excellent in wear resistance and durability by making the fine cellulose fibers, which are lightweight and have a high elastic modulus and a low linear expansion coefficient, have good interfacial adhesion with the resin.

[0006] Patent Document 3 describes a composite material containing 50 to 80 parts by weight of lignin and 20 to 50 parts by weight of polyamide having a specific structure. The composite material described in Patent Document 3 is said to have high environmental protection performance due to its high lignin content.

[0007] Non-patent document 1 describes that a molded article of a resin composition containing polypropylene grafted with maleic anhydride, glycol lignin, and carbon fibers exhibits excellent mechanical properties and thermal stability. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2016 / 104634 [Patent Document 2] Japanese Patent Publication No. 2019-203108 [Patent Document 3] Special Publication No. 2022-551770 [Non-patent literature]

[0009] [Non-Patent Document 1] Jonathon Tanks et al, “Glycol lignin / MAH-g-PP blends and composites with exceptional mechanical properties for automotive applications”, Composites Science and Technology, 238(2023), 110030 [Overview of the project] [Problems that the invention aims to solve]

[0010] As described in Patent Document 2, fibrous fillers are sometimes mixed into resin compositions to increase the tensile modulus (Young's modulus) and strength. Similarly, it is also known that plate-shaped fillers are mixed into resin compositions for the same purpose. While improvements in tensile modulus and / or strength are observed when plate-shaped or fibrous fillers are mixed into commonly used polyamides, further improvements in modulus are desired.

[0011] This invention has been made in view of the above circumstances, and aims to provide a polyamide resin composition that reduces the burden on the environment and can form a molded article with excellent elastic modulus, and a molded article thereof. [Means for solving the problem]

[0012] The inventors diligently conducted research to solve the above problems. As a result, they used a glycol such as polyethylene glycol as lignin for polyamide. at least one selected from the group consisting of glycerin and polyglycerin. We discovered that a molded article with a high elastic modulus can be obtained by mixing modified lignin, obtained by acid solubilization of wood raw materials using a solvent, with fibrous fillers, thus completing the present invention.

[0013] In other words, the present invention includes the following embodiments. [1] (A) Glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. (B) Contains 10% to 55% by mass of lignin, (C) contains 40% to 85% by mass of polyamide resin, and (D) contains 5% to 40% by mass of plate-like or fibrous filler. A lignin-containing polyamide resin composition wherein at least a portion of the (B) polyamide resin contains an aliphatic skeleton. [2] before Record Ricoh Ru is ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and Polyethylene polypropylene glyco Lu at least one type of glyco selected from the following groups InA lignin-containing polyamide resin composition according to one embodiment [1]. [3] The lignin-containing polyamide resin composition according to embodiment [2], wherein the glycol is polyethylene glycol having a weight-average molecular weight of 100 or more and 2000 or less. [4] The (B) polyamide resin is polyamide 4T, polyamide 5T, polyamide 6, polyamide 10, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 611, polyamide 612, polyamide 6 / 6I, polyamide 66 / 6I, polyamide 6I, polyamide 6T, polyamide 6T / 11, polyamide 6C, polyamide 810, polyamide 812, polyamide M8T, polyamide M8N, polyamide 9T, polyamide 9T / M8T, poly A lignin-containing polyamide resin composition according to any one of embodiments [1] to [3], wherein the composition is at least one selected from the group consisting of amide 9N, polyamide 9N / M8N, polyamide 10T, polyamide 10T / 11, polyamide 1010, polyamide 1012, polyamide 11 / 1010, polyamide 12 / 1010, polyamide 6I / 6T, polyamide 6T / 10T, polyamide 66 / 6I / 6T, polyamide 2M5T, polyamide 2M5C, and polyamide MXD6. [5] The lignin-containing polyamide resin composition according to any one of embodiments [1] to [4], wherein the (C) plate-like or fibrous filler is at least one selected from the group consisting of glass fiber, glass flake, carbon fiber, graphite, carbon nanotube, graphene, molybdenum disulfide, wollastonite, mica, talc, pyrophyllite, smectite, imogolite, potassium titanate fiber, layered titanate, calcium silicate, aramid fiber, cellulose fiber, cellulose nanofiber, and zirconium phosphate. [6] A molded article of a lignin-containing polyamide resin composition according to any one of embodiments [1] to [5]. [Effects of the Invention]

[0014] According to the above embodiment of the present invention, it is possible to obtain a polyamide resin composition capable of forming a molded article with reduced environmental load and excellent elastic modulus, and the molded article thereof. [Mode for Carrying Out the Invention]

[0015] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. Further, among the constituent elements in the following embodiments, constituent elements not described in the claims indicating the highest concept are described as optional constituent elements.

[0016] [Lignin-Containing Polyamide Resin Composition] The lignin-containing polyamide resin composition according to the first embodiment of the present invention (hereinafter sometimes simply referred to as "the lignin-containing polyamide resin composition according to the first embodiment") comprises (A) glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. lignin in an amount of 10% by mass or more and 55% by mass or less, (B) a polyamide resin in an amount of 40% by mass or more and 85% by mass or less, and (C) a plate-like or fibrous filler in an amount of 5% by mass or more and 40% by mass or less, wherein at least a part of the (B) polyamide resin contains an aliphatic polyamide resin.

[0017] The lignin-containing polyamide resin composition according to the first embodiment can be produced by mixing the raw materials constituting the composition through a general mixing process using a twin-screw extruder or the like.

[0018] <(A) Glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. Lignin> (A) Glycol, which is an essential component of the lignin-containing polyamide resin composition according to the first embodiment Modified with at least one selected from the group consisting of glycerin and polyglycerin. lignin is a modified lignin obtained by subjecting lignocellulose, which is a wood raw material, to solvolysis (acid solvolysis) in the presence of an acid catalyst using glycol at least one selected from the group consisting of glycerin and polyglycerin. as a solvent. Lignocellulose is the main component of woody or herbaceous biomass, and is composed of polysaccharide polymers such as cellulose and hemicellulose, and lignin which is a phenolic polymer.

[0019] (A) glycol from lignocellulose Modified with at least one selected from the group consisting of glycerin and polyglycerin. The method for producing lignin is not particularly limited, and known methods can be applied. For example, it can be produced by the method disclosed in Japanese Patent Publication No. 2017-197517.

[0020] Specifically, for example, cedar wood powder, which is lignocellulose, is used with glycol as a solvent. The solution is subjected to acid solubilization by heating in the presence of an acid catalyst, and after making the solution alkaline, the pulp residue fraction, whose main components are cellulose and hemicellulose, is separated to obtain a soluble fraction. Next, the obtained soluble fraction is returned to an acidic state, and the resulting precipitate is separated, washed, and dried by conventional methods to obtain (A) glycol. Modified with at least one selected from the group consisting of glycerin and polyglycerin. Lignin can be obtained. (A) Glycol of the present disclosure Modified with at least one selected from the group consisting of glycerin and polyglycerin. Lignin is glycol, which was used as a solvent in the acid solvolysis treatment. at least one selected from the group consisting of glycerin and polyglycerin. However, it is modified lignin, which is lignin that has been chemically modified.

[0021] The glycol used as a solvent in the acid solubilization treatment is not particularly limited, but examples include ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and Polyethylene polypropylene glyco Lu It may be at least one species selected from the group.

[0022] If the glycol used as the solvent in the acid solubilization treatment is polyethylene glycol, at least one ethyleneoxy group may be replaced with a propyleneoxy group, and if it is polypropylene glycol, at least one propyleneoxy group may be replaced with an ethyleneoxy group.

[0023] Glycol used as a solvent in acid solubilization treatment at least one selected from the group consisting of glycerin and polyglycerin.However, in the case of polymers such as polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol, and polyglycerin, the (A) glycol to be obtained is Modified with at least one selected from the group consisting of glycerin and polyglycerin. The molecular weight of these polymers can be appropriately selected depending on the thermal meltability of lignin, etc. For example, in the case of polyethylene glycol, the weight-average molecular weight may be 100 to 2000, and more preferably 200 to 600.

[0024] Glycol used as a solvent in acid solubilization treatment at least one selected from the group consisting of glycerin and polyglycerin. The amount used is not particularly limited, but for example, it is preferably 2 to 10 parts by mass, and more preferably 3 to 6 parts by mass, per 1 part by mass of lignocellulose.

[0025] (A) glycol in the lignin-containing polyamide resin composition according to the first embodiment Modified with at least one selected from the group consisting of glycerin and polyglycerin. The lignin content is between 10% by mass and 55% by mass. (A) Glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. By including 10% by mass or more of lignin, the resin composition will reduce its environmental impact. (A) Glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. The interaction between lignin and (B) polyamide resin and (C) plate-like or fibrous filler, described later, results in a molded article with excellent elastic modulus. On the other hand, (A) Glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. By including 55% by mass or less of lignin, the resin composition becomes capable of being sufficiently mixed using a general-purpose kneader.

[0026] (A) glycol in the lignin-containing polyamide resin composition according to the first embodiment Modified with at least one selected from the group consisting of glycerin and polyglycerin. The lignin content may be 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more, and may be 50% by mass or less, 45% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less.

[0027] (B) Polyamide resin The (B) polyamide resin, which is an essential component of the lignin-containing polyamide resin composition according to the first embodiment, contains at least a portion of an aliphatic skeleton. Polyamide resins containing an aliphatic skeleton include aliphatic polyamide resins in which the skeleton is formed of chain-linked carbon atoms, and semi-aromatic polyamide resins in which the skeleton is formed of chain-linked carbon atoms and aromatic rings. The aliphatic polyamide resin may be a polycondensate of a single monomer or a copolymer of multiple monomers. The (B) polyamide resin may consist of a polyamide resin containing an aliphatic skeleton, or it may also contain an aromatic polyamide resin (aramid).

[0028] Polyamide resins containing an aliphatic backbone include polyamide 4T, polyamide 5T, polyamide 6, polyamide 10, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 611, polyamide 612, polyamide 6 / 6I, polyamide 66 / 6I, polyamide 6I, polyamide 6T, polyamide 6T / 11, polyamide 6C, polyamide 810, polyamide 812, polyamide M8T, and polyamide 6. Examples include amide M8N, polyamide 9T, polyamide 9T / M8T, polyamide 9N, polyamide 9N / M8N, polyamide 10T, polyamide 10T / 11, polyamide 1010, polyamide 1012, polyamide 11 / 1010, polyamide 12 / 1010, polyamide 6I / 6T, polyamide 6T / 10T, polyamide 66 / 6I / 6T, polyamide 2M5T, polyamide 2M5C, and polyamide MXD6. The polyamide resins may be used individually or in combination of two or more types. Alternatively, one or more of the polyamide resins selected from the above may be used in combination with other polyamide resins.

[0029] Of the polyamide resins mentioned above, the glycol (A) used in combination. Modified with at least one selected from the group consisting of glycerin and polyglycerin.From the standpoint of increasing the lignin content, it is preferable to use one or more selected from polyamide 6, polyamide 66, polyamide 11, and polyamide 12, as this can further increase the elastic modulus of the molded article. Furthermore, from the standpoint of increasing the strength of the molded article, it is preferable to use one or more selected from polyamide 66 and polyamide 11. In addition, from the standpoint of increasing the proportion of biomass-derived components in the resin composition, it is preferable to use one or more selected from polyamide 11, polyamide 610, polyamide 810, and polyamide 1010.

[0030] In the lignin-containing polyamide resin composition according to the first embodiment, the content of (B) polyamide resin is 40% by mass or more and 85% by mass or less. Including 40% by mass or more of polyamide resin makes the resin composition easily mixable by a general-purpose kneader. On the other hand, including 85% by mass or less of polyamide resin makes it possible to mix the other essential component, (A) glycol. Modified with at least one selected from the group consisting of glycerin and polyglycerin. The content of lignin and (C) plate-like or fibrous filler is ensured, and the resulting molded article has excellent elastic modulus.

[0031] The content of (B) polyamide resin in the lignin-containing polyamide resin composition according to the first embodiment may be 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, or 65% by mass or more, and may be 80% by mass or less, 75% by mass or less, 70% by mass or less, 65% by mass or less, or 60% by mass or less.

[0032] <(C) Plate-shaped or fibrous filler> (C) A plate-like or fibrous filler, which is an essential component of the lignin-containing polyamide resin composition according to the first embodiment, is (A) glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin.The interaction between lignin and (B) polyamide resin significantly improves the elastic modulus of the molded article of the resin composition. In this disclosure, "plate-like" means a shape in which the ratio (L / T) of the maximum dimension (length) L to the minimum dimension (thickness) T in a direction perpendicular to the maximum dimension is 10 or more, and "fibrous" means a shape in which the ratio (L / D) of the maximum dimension (length) L to the maximum dimension (diameter) D in a direction perpendicular to the maximum dimension is 10 or more. When the filler is an aggregate of multiple fibers, the value of each ratio means the average value for each plate or fiber. When the lignin-containing polyamide resin composition according to the first embodiment contains a fibrous filler as (C) plate-like or fibrous filler, (A) glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. Increasing the contact area with lignin and (B) polyamide resin increases the interaction with these components, further improving the elastic modulus of the molded article of the resin composition.

[0033] (C) Examples of plate-shaped or fibrous fillers include glass fibers, glass flakes, carbon fibers, graphite, carbon nanotubes, graphene, molybdenum disulfide, wollastonite, mica, talc, pyrophyllite, smectite, imogolite, potassium titanate fibers, layered titanates, calcium silicate, aramid fibers, cellulose fibers, cellulose nanofibers, and zirconium phosphate. The plate-shaped or fibrous fillers may be used alone or in combination of two or more types. The use of two or more plate-shaped or fibrous fillers in combination includes the use of multiple types of plate-shaped or fibrous fillers made of the same material but with different L / T or L / D values.

[0034] In the lignin-containing polyamide resin composition according to the first embodiment, the content of (C) plate-like or fibrous filler is 5% by mass or more and 40% by mass or less. Including 5% by mass or more of plate-like or fibrous filler results in a molded article with excellent elastic modulus. On the other hand, including 40% by mass or less of plate-like or fibrous filler allows for sufficient mixing with a general-purpose kneader, and the resulting molded article has excellent strength.

[0035] The content of (C) plate-like or fibrous filler in the lignin-containing polyamide resin composition according to the first embodiment may be 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, and may be 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass or less.

[0036] <Other ingredients> The lignin-containing polyamide resin composition according to the first embodiment may contain other components to impart various properties to the resulting composition, to the extent that the effects of the present invention are not impaired. Examples of other components include (B) resins other than polyamide resin, elastomers, and various additives.

[0037] Examples of additives include inorganic fillers such as talc, calcium carbonate, metal powder, titanium dioxide, and zinc oxide (excluding those that fall under (C) plate-shaped or fibrous fillers), colorants such as pigments and dyes, antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, antistatic agents, nucleating agents, dispersants, flame retardants, flame retardant aids, and plasticizers. The content of additives in the lignin-containing polyamide resin composition is not particularly limited, but for example, it can be 0.01% by mass or more and 30% by mass or less of the total lignin-containing polyamide resin composition.

[0038] [Molded body] A molded article according to a second embodiment of the present invention (hereinafter sometimes simply referred to as "a molded article according to a second embodiment") is a molded article obtained by molding the lignin-containing polyamide resin composition according to the first embodiment described above.

[0039] The molding method for obtaining the molded article is not particularly limited, and known methods for molding polyamide resins can be employed. Examples include extrusion molding, injection molding, blow molding, extrusion blow molding, injection blow molding, press molding, and vacuum molding.

[0040] The molded article may be a molded article formed from the lignin-containing polyamide resin composition according to the first embodiment, or it may be a molded article having a portion, such as a surface layer or a core, formed from the lignin-containing polyamide resin composition according to the first embodiment.

[0041] The applications of the molded products are not particularly limited. For example, they can be used in a wide range of fields, including home appliance materials and parts, communication equipment parts, electrical components, electronic components, automobile parts, other vehicle parts, ship and aircraft materials, mechanical components, building materials, civil engineering components, agricultural materials, power tool parts, food containers, films, sheets, and fibers. [Examples]

[0042] The present invention will be described in detail below with reference to examples, etc., but the present invention is not limited to these.

[0043] [material] The materials used for the lignin-containing polyamide resin compositions in the examples and comparative examples are as follows:

[0044] (A) Glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. Lignin: Derived from lignin. GL400: Lignin modified with polyethylene glycol with a weight-average molecular weight of 400. GL600: Lignin modified with polyethylene glycol with a weight-average molecular weight of 600.

[0045] (B) Polyamide resin PA6: Polyamide 6 (manufactured by Toray Industries, Inc., Amilan® CM1007) PA66: Polyamide 66 (manufactured by Toray Industries, Inc., Amilan® CM3001-N) PA11: Polyamide 11 (manufactured by Arkema Corporation, RILSAN® BML OTLD) PA12: Polyamide 12 (manufactured by Ube Industries, Ltd., UBE Nylon® 3024U) PA6I / 6T: Polyamide 6I / 6T (Isophthalic acid content in total dicarboxylic acid units: 70 mol%) (Manufactured by MS Chemie Japan Co., Ltd., Grivory® G21)

[0046] (C) Plate-like or fibrous filler CF: Chopped carbon fiber with a fiber diameter of 7 μm and a fiber length of 6 mm (aspect ratio (L / W) ≈ 850) (manufactured by Mitsubishi Chemical Corporation, Pyrofil® TR06NL) GF: Chopped glass fiber with a fiber diameter of 13 μm and a fiber length of 3 mm (aspect ratio (L / W) ≈ 230) (manufactured by Nitto Boseki Co., Ltd., CS3PE944)

[0047] [Comparative Examples 1 to 7, and Examples 1 to 6] <Preparation of lignin-containing polyamide resin composition and molded article> In Comparative Examples 1 to 7 and Examples 1 to 6, PA6 was used as the (B) polyamide resin. Materials containing each component shown in Table 1 were melt-kneaded in a twin-screw kneader (S1KRC, manufactured by Kurimoto Iron Works Co., Ltd.) at a cylinder temperature of 230-250°C to produce pellets. Dumbbell test specimens (ISO 527-2) were molded from the dried pellets using a small injection molding machine (Mini JET II, ​​manufactured by Thermo Fisher Scientific Inc.) at a cylinder temperature of 220-250°C and a mold temperature of 80°C.

[0048] <Measurement of molded product properties> Tensile tests were performed on the dumbbell specimens for each comparative example and example in accordance with ASTM D638, and the tensile modulus and tensile strength were calculated. The tensile tests were performed using an electromechanical testing machine (Shimadzu Corporation, EZ-LX) at a crosshead speed of 5 mm / min. The strain necessary for calculating the tensile modulus was measured using a video non-contact elongation meter (video extensometer). Tensile tests were performed on N=3 dumbbell specimens for each example and comparative example, and the tensile modulus and tensile strength were taken as the average of the values ​​calculated for each specimen. The obtained tensile modulus and tensile strength are shown in Table 1.

[0049] [Table 1]

[0050] [Comparative Examples 8 to 14, and Examples 7 to 15] In Comparative Examples 8 to 14 and Examples 7 to 15, PA11 was used as the (B) polyamide resin, and the composition of each component was changed as shown in Table 2. Except for these changes, dumbbell specimens were prepared in the same manner as in Comparative Example 1, and tensile tests were performed to calculate the tensile modulus and tensile strength. The obtained tensile modulus and tensile strength are shown in Table 2.

[0051] [Table 2]

[0052] [Examples 16 to 19] In Examples 16 to 19, PA12 was used as the (B) polyamide resin, and the composition of each component was changed as shown in Table 3. Except for these changes, dumbbell specimens were prepared in the same manner as in Comparative Example 1, and tensile tests were performed to calculate the tensile modulus and tensile strength. The obtained tensile modulus and tensile strength are shown in Table 3.

[0053] [Table 3]

[0054] [Comparative Examples 15 to 18, and Examples 20 to 21] In Comparative Examples 15 to 18 and Examples 20 to 21, dumbbell specimens were prepared in the same manner as in Comparative Example 1, except that PA66 was used as the (B) polyamide resin and the composition of each component was changed as shown in Table 4. Tensile tests were then performed, and the tensile modulus and tensile strength were calculated. The obtained tensile modulus and tensile strength are shown in Table 4.

[0055] [Table 4]

[0056] [Comparative Examples 19 to 21, and Example 22] In Comparative Examples 19 to 21 and Example 22, dumbbell specimens were prepared in the same manner as in Comparative Example 1, except that PA6T / 6I was used as the (B) polyamide resin and the composition of each component was changed as shown in Table 5. Tensile tests were then performed, and the tensile modulus and tensile strength were calculated. The obtained tensile modulus and tensile strength are shown in Table 5.

[0057] [Table 5]

[0058] As shown in Tables 1 to 5, (A) glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. The molded articles obtained from the lignin-containing polyamide resin compositions according to each example, which contained lignin, (B) polyamide resin, and (C) plate-like or fibrous filler in specific proportions, had a higher tensile modulus of elasticity compared to the molded articles obtained from the lignin-containing polyamide resin composition according to the comparative example, which did not contain (C) plate-like or fibrous filler. Furthermore, the molded articles obtained from the lignin-containing polyamide resin compositions according to each example contained the same amount of the same type of (C) plate-like or fibrous filler and (A) glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. The tensile modulus was higher than that obtained from the polyamide resin composition of the comparative example which did not contain lignin. The molded article obtained from the lignin-containing polyamide resin composition of the example contained the same amount of (C) plate-like or fibrous filler and (A) glycol. Modified with at least one selected from the group consisting of glycerin and polyglycerin. The fact that it has a higher tensile modulus than the molded article obtained from the polyamide resin composition of the comparative example that does not contain lignin is due to (A) glycol Modified with at least one selected from the group consisting of glycerin and polyglycerin. This suggests that the interaction between lignin, (B) polyamide resin, and (C) plate-like or fibrous filler contributes to the improvement of the tensile modulus.

[0059] Furthermore, when (B) the polyamide resin is PA11 or PA66, as can be seen from the comparison between Comparative Example 12 and Examples 7, 10, or 13, Comparative Example 13 and Examples 8, 11, or 14, Comparative Example 14 and Examples 9, 12, or 15, Comparative Example 16 and Example 20, and Comparative Example 17 and Example 21, the molded article obtained from the lignin-containing polyamide resin composition according to the example contains the same amount of (C) plate-like or fibrous filler and (A) glycol. Modified with at least one selected from the group consisting of glycerin and polyglycerin. The molded article had higher tensile strength than the molded article obtained from the polyamide resin composition of the comparative example that did not contain lignin. [Industrial applicability]

[0060] According to the present invention, a polyamide resin composition capable of forming molded articles with reduced environmental impact and excellent elastic modulus can be obtained, as well as molded articles thereof. Therefore, the lignin-containing polyamide resin composition of the present invention can be widely used in polyamide application fields, including automotive components.

Claims

1. (A) 10% to 55% by mass of modified lignin chemically modified with at least one selected from the group consisting of glycol, glycerin, and polyglycerin, (B) 40% to 85% by mass of polyamide resin, and (C) 5% to 40% by mass of plate-like or fibrous filler. A lignin-containing polyamide resin composition wherein at least a portion of the polyamide resin (B) contains an aliphatic skeleton.

2. The lignin-containing polyamide resin composition according to claim 1, wherein the glycol is at least one selected from the group consisting of ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and polyethylene-polypropylene glycol.

3. The lignin-containing polyamide resin composition according to claim 2, wherein the glycol is polyethylene glycol having a weight-average molecular weight of 100 or more and 2000 or less.

4. The (B) polyamide resin is polyamide 4T, polyamide 5T, polyamide 6, polyamide 10, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 611, polyamide 612, polyamide 6 / 6I, polyamide 66 / 6I, polyamide 6I, polyamide 6T, polyamide 6T / 11, polyamide 6C, polyamide 810, polyamide 812, polyamide M8T, polyamide M8N, polyamide 9T, polyamide 9T / The lignin-containing polyamide resin composition according to claim 1, wherein the lignin-containing polyamide resin composition is at least one selected from the group consisting of M8T, polyamide 9N, polyamide 9N / M8N, polyamide 10T, polyamide 10T / 11, polyamide 1010, polyamide 1012, polyamide 11 / 1010, polyamide 12 / 1010, polyamide 6I / 6T, polyamide 6T / 10T, polyamide 66 / 6I / 6T, polyamide 2M5T, polyamide 2M5C, and polyamide MXD6.

5. The lignin-containing polyamide resin composition according to claim 1, wherein the (C) plate-like or fibrous filler is at least one selected from the group consisting of glass fiber, glass flake, carbon fiber, graphite, carbon nanotube, graphene, molybdenum disulfide, wollastonite, mica, talc, pyrophyllite, smectite, imogolite, potassium titanate fiber, layered titanate, calcium silicate, aramid fiber, cellulose fiber, cellulose nanofiber, and zirconium phosphate.

6. A molded article of a lignin-containing polyamide resin composition according to any one of claims 1 to 5.

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