Polyamide resin composition, method for producing the same, and molded article containing the same

Abstract

This invention relates to a polyamide resin composition, a method for producing the same, and a molded article containing the same. According to the present invention, a polyamide resin composition, a method for producing the same, and a molded article containing the same are provided, which have excellent tensile strength and flexural modulus, as well as excellent heat aging resistance, minimizing the effects of heat and other factors due to exposure to the external environment.

Description

Technical Field

[0001] [Cross-reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0058654 filed on May 2, 2024, and all the contents disclosed in the literature of the Korean patent application are incorporated herein by reference as part of this specification.

[0002] The present invention relates to a polyamide resin composition, a method for producing the same, and a molded article containing the same. More specifically, the present invention relates to a polyamide resin composition, a method for producing the same, and a molded article containing the same, which are excellent in tensile strength and flexural modulus, and have excellent heat aging resistance, so that the influence of heat and the like due to exposure to the external environment is minimized, and thus are useful for applications in automobiles or electric and electronic products where the use environment exceeds 150°C, particularly where heat resistance of 200°C or higher is required.

Background Art

[0003] In recent years, many studies have been made to resinize automotive parts in order to improve the fuel efficiency of automobiles, and polyamide resins having excellent heat resistance and solvent resistance are widely used as materials for automotive parts.

[0004] However, the polyamide resin has a problem that it is difficult to apply to automotive parts or electric and electronic parts that require heat resistance of 200°C or higher due to insufficient heat resistance.

[0005] On the other hand, typical heat stabilizers that can provide heat resistance to the polyamide resin include polyhydric alcohols such as pentaerythritol, dipentaerythritol, and tripentaerythritol.

[0006] However, these components have a drawback in that while providing high heat stability, they cause a whitening phenomenon in which they migrate under high temperature and high humidity environments and white the surface of the product.

[0007] Therefore, there is an urgent need to develop polyamide resin compositions that are excellent in tensile strength and flexural modulus, have excellent heat aging resistance, and do not exhibit whitening, making them applicable to automotive parts or electrical and electronic components. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2014-148560 [Overview of the project] [Problems that the invention aims to solve]

[0009] To solve the problems of the conventional technology described above, the present invention aims to provide a polyamide resin composition, a method for producing the same, and a molded article containing the same, which is particularly suitable for use as a substitute part for metal parts in automobiles or electrical and electronic products that operate in high-temperature environments, due to its excellent tensile strength and flexural modulus, and excellent heat aging resistance, thereby minimizing the effects of heat and other factors due to exposure to the external environment.

[0010] The above-mentioned and other objectives of the present invention can all be achieved by the present invention as described below. [Means for solving the problem]

[0011] To achieve the above objective, the present invention provides a polyamide resin composition comprising I) (A) a polyamide resin, (B) glass fibers, and (C) an ether compound, wherein the (C) ether compound comprises (C-1) an ether compound having an OH value in the range of 35 to 40 mgKOH / g, and (C-2) an ether compound having an OH value in the range of 1190 to 1320 mgKOH / g.

[0012] Furthermore, the present invention provides a polyamide resin composition characterized by comprising: II) (A) 39 to 95% by weight of polyamide resin; (B) 4.4 to 40% by weight of glass fiber; (C-1) 0.5 to 10% by weight of an ether compound having an OH value in the range of 35 to 40 mgKOH / g; (C-2) 0.1 to 10% by weight of an ether compound having an OH value in the range of 1190 to 1320 mgKOH / g; and (D) 5% by weight or less of an additive.

[0013] III) In I) to II) above, the (C-1) ether compound may have a number average molecular weight of 20,000 g / mol or less.

[0014] IV) In I) to III) above, the (C-2) ether compound may have a number average molecular weight of 2,000 g / mol or less.

[0015] V) In I) to IV) above, the (C-1) ether compound and the (C-2) ether compound may be present in a weight ratio of 1:0.5 to 1:5 (C-1:C-2).

[0016] VI) In I) to V) above, the glass fiber may contain 52-56% by weight of silica, 12-16% by weight of alumina, 21-25% by weight of calcium oxide and magnesia (where magnesia is 1.5% by weight or less), 1% by weight or less of titanium dioxide, 5-8% by weight of boron oxide, and a remainder of less than 2.0% by weight including sodium oxide, potassium oxide and iron oxide.

[0017] VII) In I) to VI) above, the additive may be one or more selected from heat stabilizers, light stabilizers, lubricants, and antioxidants.

[0018] VIII) In the above I) to VII), the polyamide resin composition may exhibit a tensile strength of 170 MPa or more, measured in accordance with ISO 527 under conditions of a gauge length of 50 mm, a test speed of 5.0 mm / min, and 23°C.

[0019] IX) In the above I) - VIII), the polyamide resin composition may exhibit a flexural modulus of elasticity of 8,000 MPa or more measured in accordance with ISO 178 at a span of 64 mm and a test speed of 2.0 mm / min.

[0020] Further, the present invention provides a method for producing a polyamide resin composition, comprising the steps of kneading and extruding (X) (A) a polyamide resin, (B) glass fibers, and (C) an ether compound, wherein the (C) ether compound includes (C - 1) an ether compound having an OH value within the range of 35 to 40 mgKOH / g; and (C - 2) an ether compound having an OH value within the range of 1190 to 1320 mgKOH / g.

[0021] Also, the present invention provides a method for producing a polyamide resin composition, comprising the steps of kneading and extruding (XI) 39 - 89.4% by weight of (A) a polyamide resin, 4.4 - 40% by weight of (B) glass fibers, 0.5 - 10% by weight of (C - 1) an ether compound having an OH value within the range of 35 to 40 mgKOH / g, 0.1 - 10% by weight of (C - 2) an ether compound having an OH value within the range of 1190 to 1320 mgKOH / g, and 0 - 5% by weight of an additive.

[0022] XII) In the above X) - XI), the extrusion conditions may be a temperature condition of 280 - 310°C.

[0023] The present invention also provides a molded article comprising the above - described polyamide resin composition.

[0024] XIV) In the above XIII), the molded article may be an automotive part or an electric and electronic part.

Advantages of the Invention

[0025] According to the present invention, there is provided a polyamide resin composition, a method for producing the same, and a molded article containing the same, which are excellent in tensile strength and flexural modulus, and have excellent heat aging resistance, so that the effects of heat and the like due to exposure to the external environment are minimized. As a result, the polyamide resin composition is useful for applications in automobiles or electric and electronic products where the use environment exceeds 150°C, particularly where heat resistance of 200°C or higher is required.

Embodiments for Carrying Out the Invention

[0026] Hereinafter, the polyamide resin composition, the method for producing the same, and the molded article containing the same described herein will be described in detail.

[0027] When the inventors of the present invention produce a polyamide resin composition by mixing a polyamide resin, glass fiber, and an ether compound satisfying a specific OH value at a predetermined composition ratio, it has been confirmed that a molded article containing such a polyamide resin composition is excellent in tensile strength and flexural modulus, has excellent heat aging resistance, and is hardly affected by heat and the like due to exposure to the external environment. Based on this, the inventors further advanced their research and completed the present invention.

[0028] The polyamide resin composition described herein is characterized by containing a polyamide resin, glass fiber, and two kinds of ether compounds having different OH values. In such a case, it is excellent in tensile strength and flexural modulus, and due to its excellent heat aging resistance, the effects of heat and the like due to exposure to the external environment are minimized. As a result, it has the advantage of being useful for applications in automobiles or electric and electronic products where the use environment exceeds 150°C, particularly where heat resistance of 200°C or higher is required.

[0029] As another example, the polyamide resin composition described herein comprises (A) a polyamide resin, (B) glass fibers, and (C) an ether compound, wherein the (C) ether compound is characterized by comprising (C-1) an ether compound having an OH value in the range of 35 to 40 mgKOH / g, and (C-2) an ether compound having an OH value in the range of 1190 to 1320 mgKOH / g. In such a case, the tensile strength and flexural modulus are excellent, and the excellent heat aging resistance minimizes the effects of heat from exposure to the external environment. This has the advantage of being useful in applications such as automobiles or electrical and electronic products where the operating environment exceeds 150°C, and especially where heat resistance of 200°C or higher is required.

[0030] As another example, the polyamide resin composition described herein is characterized by containing (A) 39 to 89.4% by weight of polyamide resin, (B) 4.4 to 40% by weight of glass fiber, (C-1) 0.5 to 10% by weight of an ether compound having an OH value in the range of 35 to 40 mgKOH / g, (C-2) 0.1 to 10% by weight of an ether compound having an OH value in the range of 1190 to 1320 mgKOH / g, and (D) 5% by weight or less of additives. In such a case, it has excellent tensile strength and flexural modulus, and excellent heat aging resistance minimizes the effects of heat and other factors due to exposure to the external environment. This has the advantage of being useful in applications such as automobiles or electrical and electronic products where the operating environment exceeds 150°C, and especially where heat resistance of 200°C or higher is required.

[0031] The components constituting the polyamide resin composition described herein are explained in detail below.

[0032] (A) Polyamide resin The polyamides described herein include, as examples, polyamide 6, polyamide 66, polyamide 46, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 6 / 66, polyamide 6 / 612, polyamide MXD6, polyamide 6 / MXD6, polyamide 66 / MXD6, polyamide 6T, polyamide 6I, polyamide 6 / 6T, polyamide 6 / 6I, polyamide 66 / 6T, polyamide 66 / 6I, polyamide 6 / 6T / 6I, polyamide 66 / 6T / 6I, polyamide 9T, polyamide 9I, polyamide 6 / 9T, and It may be one or more selected from the group consisting of polyamide 6 / 9I, polyamide 66 / 9T, polyamide 6 / 12 / 9T, polyamide 66 / 12 / 9T, polyamide 6 / 12 / 9I, and polyamide 66 / 12 / 6I, and more preferably a homopolymer or copolymer containing one or more selected from polyamide 6, polyamide 66, polyamide 46, polyamide 11, and polyamide 12, most preferably containing polyamide 66, in which case it has the effect of excellent heat resistance, moldability, and chemical resistance.

[0033] The polyamide may preferably be present in an amount of 59% by weight or more of the total 100% by weight of the polyamide resin composition, more preferably 39 to 89.4% by weight, and even more preferably 59 to 63% by weight. Within this range, there is an effect of having excellent mechanical properties, including tensile strength and impact strength, as well as excellent heat resistance.

[0034] The polyamide may be manufactured by methods commonly used in the art to which the present invention pertains, or is commercially available, and is not particularly limited, as long as it conforms to the definition of the present invention.

[0035] (B) Glass fiber This description includes glass fibers to enhance the mechanical properties, heat resistance, and dimensional stability of the polyamide resin composition.

[0036] When the aforementioned glass fibers are included in the polyamide resin composition, the mechanical properties such as tensile strength, impact strength, and elongation, as well as the heat resistance properties of the molded article formed from the resin composition, can be improved.

[0037] In order to ensure the fluidity of the resin composition required in the field of parts molding using the aforementioned polyamide resin composition, a specific glass material from among the glass fibers is introduced. For example, when the glass fiber described later is introduced in the field of replacing metal materials in automotive system modules, it has the effect of maintaining sufficient heat resistance and mechanical properties of the base resin, while ensuring sufficient processability and moldability.

[0038] The aforementioned glass fibers can be selected from one or more types, consisting of a first glass fiber with a tensile modulus of 83-87 GPa measured in accordance with ASTM D2343 for a 17 μm-2400 tex roving strand, and a second glass fiber with a tensile modulus of 88-92 GPa. When using such high-rigidity glass fibers, it is possible to reduce the deterioration of surface appearance due to glass fiber protrusion and gas flow mark defects during injection molding. Furthermore, it is possible to attempt product development considering the deviation of physical properties due to the orientation of glass fibers in different parts of the component, and it is advantageous in terms of flatness and deformation.

[0039] The glass fiber may, for example, have a circular or non-circular cross-section, or it may be a flat type with a non-circular cross-section, such as an elliptical or irregular shape.

[0040] In this description, the circular, elliptical, and irregular shapes of the cross-section are not particularly limited, as long as they are circular, elliptical, and irregular shapes of cross-section that are commonly recognized in the art to which the present invention pertains.

[0041] In this description, "circular" refers to a cross-section that is circular in shape and where the dimensional ratio of the principal cross-sectional axis to the secondary cross-sectional axis is close to 1, or 1, but is not limited to this.

[0042] In this description, "elliptical" refers to, but is not limited to, a cross-section that is elliptical in shape and has a dimensional ratio of 2:6, 3:6, or 3.5:5.0 between the principal and secondary cross-sectional axes.

[0043] In this description, "non-standard" refers, for example, to cases where the cross-section is not circular or elliptical, but is not limited to this.

[0044] In this description, the glass fiber may be used together with other inorganic fibers, the inorganic fibers being one or more selected from natural fibers such as carbon fiber, basalt fiber, kenaf, or hemp.

[0045] The glass fibers described herein may be circular or non-circular cross-section glass fibers with a silica content of 52% by weight or more, or 52-66% by weight. In this case, when product design and design changes are considered simultaneously, it is possible to ensure high rigidity, lightweight construction, and appearance quality to a degree that can replace existing metals.

[0046] For example, when the aspect ratio of the glass fiber, expressed as the ratio of length (L) to diameter (D) (L / D), is 1:1 to 1:4, specifically 1:1 to 1:3, and more specifically 1:1, it can provide high strength, high toughness, and improved elongation and surface appearance quality in the polyamide resin composition described herein. When the aspect ratio is 1:3 to 1:4, and more specifically 1:4, it can provide high strength, high toughness, and suitable products in terms of flatness, deformation, and orientation.

[0047] In this description, diameter and length can be measured using a scanning electron microscope (SEM). Specifically, 20 inorganic fillers are selected using a scanning electron microscope, and their respective diameters and lengths are measured using an icon bar (bar) capable of measuring diameter. The arithmetic mean is then calculated to determine the average diameter and average length.

[0048] The aforementioned D may, for example, have an average diameter of 6 to 16 μm, preferably 7 to 11 μm, and more preferably 10 to 11 μm. When the above range is satisfied, it has the effect of improving processability and improving the tensile strength of molded articles produced by molding the polyamide resin composition described herein.

[0049] In this description, the glass fiber comprises 58-62% by weight of silica, 14-18% by weight of alumina, 17-24% by weight of calcium oxide and magnesia (where calcium oxide is 10% or more by weight and magnesia is 10% or less by weight), 0.5-2% by weight of titanium dioxide, and a remainder of 1.3% or less by weight including sodium oxide, potassium oxide, and iron oxide. In this case, a polyamide resin composition with an excellent balance of physical properties such as processability, specific gravity, and mechanical properties can be secured, and molded articles with high rigidity and high toughness at a level that can replace metal can be provided.

[0050] The glass fiber comprises 52-56% by weight of silica, 12-16% by weight of alumina, 21-25% by weight of calcium oxide and magnesia (where magnesia is 1.5% by weight or less), 1% by weight or less of titanium dioxide, 5-8% by weight of boron oxide, and a remainder of less than 2.0% by weight including sodium oxide, potassium oxide, and iron oxide. In this case, a polyamide resin composition with an excellent balance of physical properties such as processability, specific gravity, and mechanical properties can be secured, and molded articles with high rigidity and high toughness at a level that can replace metal can be provided.

[0051] The glass fibers may be circular glass fibers having a circular cross-section, with a total amount of calcium oxide and magnesium of 17-24% by weight. In this case, a polyamide resin composition with an excellent balance of physical properties such as processability, specific gravity, and mechanical properties can be secured, and molded articles with high rigidity and high toughness at a level that can replace metal can be provided.

[0052] The glass fibers may be flat glass fibers with a non-circular cross-section, where the total amount of calcium oxide and magnesium is 21-25% by weight. In this case, a polyamide resin composition with an excellent balance of processability, specific gravity, and mechanical properties can be secured, and molded articles with high rigidity and toughness at a level that can replace metal can be provided.

[0053] As a specific example, glass fibers may be represented by the general formula AaBbCcDd.

[0054] In the case of the ultra-high rigidity grade, it exhibits the characteristic of 0.5 ≤ c ≤ 5, while in the case of other general-purpose grades, it exhibits the characteristics of 20 ≤ c ≤ 24, 2 ≤ d ≤ 5, and 22 ≤ c + d ≤ 29 in the general formula, confirming that the composition is different.

[0055] Contrary to what is publicly known in the industry, it has been confirmed through the examples described later that, for the polyamide resin composition described herein, it is preferable to use a high-rigidity grade with a circular cross-section or a high-strength flat grade with a non-circular (flat) cross-section, rather than an ultra-high-rigidity grade, in order to improve tensile strength and injection moldability.

[0056] In this description, the glass fibers may be treated with glass fiber sizing compositions during the manufacturing or post-processing of the fibers, and the glass fiber sizing compositions include lubricants, coupling agents, and surfactants.

[0057] The lubricant is mainly used to form good strands during the manufacture of glass fibers, and the coupling agent enables good adhesion between the glass fibers and the polyamide resin. When used appropriately, taking into account the types of polyamide resin and glass fibers, it is possible to impart excellent physical properties to the glass fiber-reinforced polyamide resin composition.

[0058] Methods for using the coupling agent include direct treatment of glass fibers and addition to an organic matrix. In order to fully utilize the performance of the coupling agent, its content must be appropriately selected.

[0059] Examples of the coupling agents include amine-based coupling agents, acrylic-based coupling agents, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)γ-aminopropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

[0060] As a specific example, the glass fiber can be a circular, high-rigidity glass fiber containing 58-62% by weight of silica, 14-18% by weight of alumina, 17-24% by weight of calcium oxide and magnesia (where calcium oxide is 10% or more by weight and magnesia is 10% or less by weight), 0.5-2% by weight of titanium dioxide, and a remainder of 1.3% or less by weight including sodium oxide, potassium oxide, and iron oxide, having an aspect ratio (L / D) of 1:1 as shown by the ratio of length (L) to diameter (D) (L / D), and a diameter of 6-16 μm.

[0061] As a specific example, the glass fiber can be a non-circular, high-strength flat glass fiber containing 52-56% by weight of silica, 12-16% by weight of alumina, 21-25% by weight of calcium oxide and magnesia (where magnesia is 1.5% by weight or less), 1% by weight or less of titanium dioxide, 5-8% by weight of boron oxide, and less than 2.0% by weight of the remainder including sodium oxide, potassium oxide, and iron oxide, with an aspect ratio (L / D) of greater than 1:1 and 1:4 or less, and a diameter of 6-16 μm.

[0062] Preferably, the glass fibers may be present in an amount of 30% by weight or more of the total 100% by weight of the polyamide resin composition, more preferably 4.4 to 40% by weight, and even more preferably 33 to 38% by weight. Within this range, when product design and design changes are considered simultaneously, it is possible to ensure high rigidity and appearance quality that can replace existing metals.

[0063] The aforementioned glass fibers may be manufactured by methods commonly used in the art to which the present invention pertains, or commercially available, and are not particularly limited, as long as they conform to the definition of the present invention.

[0064] (C) ether compounds The ether compounds described herein are added to polyamide resins to provide so-called heat stability, achieving heat resistance at high temperatures of 200°C or higher while eliminating the whitening phenomenon.

[0065] The ether compounds described herein may include ether compounds having a (C-1)OH value in the range of 35 to 40 mgKOH / g, and ether compounds having a (C-2)OH value in the range of 1190 to 1320 mgKOH / g.

[0066] The ether compounds having a (C-1)OH value in the range of 35 to 40 mgKOH / g, and the ether compounds having a (C-2)OH value in the range of 1190 to 1320 mgKOH / g, can, for example, be included in a weight ratio of 1:0.5 to 1:3 (C-1:C-2), preferably in a weight ratio of 1:0.7 to 1:2.5 (C-1:C-2), and more preferably in a weight ratio of 1:1 to 1:2 (C-1:C-2). In this case, there is an effect of having excellent mechanical properties, including tensile strength and impact strength, and heat resistance.

[0067] (C-1) ether compounds Ether compounds with an OH value in the range of 35-40 mgKOH / g may be included as components to impart an improved surface appearance by providing the aforementioned heat resistance stability.

[0068] The aforementioned OH value can be measured through standard methods such as ASTM D4274, ASTM D1899, ASTM D1957, and ASTM D6321.

[0069] If the ether compound has more than 40 mg KOH / g of hydroxyl groups, the ether compound may not be able to sufficiently permeate to the surface, and the whitening phenomenon may not be improved with small amounts. Therefore, the hydroxyl groups may be included in a range of 40 mg KOH / g or less, for example, 35 to 40 mg KOH / g. In this case, it is even more preferable because the thermal bonding strength between the components constituting the polyamide resin composition can be improved.

[0070] Such ether compounds may preferably be present in an amount of 0.5 to 10% by weight, more preferably 0.4 to 2.44% by weight, even more preferably 0.5 to 2.4% by weight, and even more preferably 0.8 to 2.2% by weight, per 100% by weight of the total polyamide resin composition. In this case, even a small amount of addition not only facilitates kneading and molding, but also has the advantage of not degrading the inherent mechanical properties of the polyamide resin, while significantly improving tensile strength, flexural modulus, and heat resistance.

[0071] Ether compounds with an OH value in the range of 35-40 mgKOH / g may include, for example, poly(tetramethylene ether) glycol.

[0072] Ether compounds having an OH value in the range of 35-40 mgKOH / g can be those produced by methods commonly used in the art to which the present invention belongs, or commercially available products, within limits that conform to the definition of the present invention, and are not particularly limited. For example, PTMG3000, PTMG2000, PTMG2000 products, etc., can be used.

[0073] (C-2) ether compounds Ether compounds having an OH value in the range of 1190 to 1320 mgKOH / g may be included together with the aforementioned (C-1) ether compound as a component to impart heat aging resistance and improved surface appearance to the polyamide resin composition. In this case, the thermal bonding strength between the components constituting the polyamide resin composition can be sufficiently improved.

[0074] The ether compound having an OH value in the range of 1190 to 1320 mgKOH / g may preferably be present in an amount of 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, even more preferably 1 to 5% by weight, and even more preferably 1 to 3% by weight, in the total 100% by weight of the polyamide resin composition. In this case, even a small amount of addition not only facilitates kneading and molding, but also has the advantage of not reducing the inherent mechanical properties of the polyamide resin, while greatly improving tensile strength, flexural modulus, and heat resistance.

[0075] The ether compounds having an OH value in the range of 1190 to 1320 mgKOH / g may be those produced by methods commonly used in the art to which the present invention belongs, or commercially available products, within limits that conform to the definition of the present invention, and are not particularly limited.

[0076] The ether compound having an OH value in the range of 1190 to 1320 mgKOH / g may, for example, be dipentaerythritol.

[0077] (D) Additives The additives described herein may be one or more selected from lubricants, antioxidants, heat stabilizers, and light stabilizers. In this case, the desired physical properties are achieved without degrading the inherent physical properties of the polyamide resin composition described herein.

[0078] The lubricant may, for example, be one or more selected from the group consisting of alkyl acrylate polymers, styrene-acrylonitrile copolymers having a weight-average molecular weight of 30,000 to 70,000 g / mol, ethylene copolymers, olefin waxes, and aliphatic amide compounds. Preferably, it may be one or more selected from the group consisting of alkyl acrylate polymers, styrene-acrylonitrile copolymers having a weight-average molecular weight of 30,000 to 70,000 g / mol, and olefin waxes. More preferably, it may be an alkyl acrylate polymer, in which case it has excellent balance of physical properties and excellent scratch resistance, resulting in excellent appearance quality.

[0079] As an example, the lubricant may be present in an amount of 5% by weight or less, preferably 0.1 to 5% by weight, of the total 100% by weight of the polyamide resin composition, and within this range, the effect of having excellent release properties and fluidity is obtained.

[0080] The alkyl acrylate polymer may preferably be one or more selected from the group consisting of poly(methyl acrylate), poly(ethyl acrylate), and poly(butyl acrylate). In this case, the formation of mold deposits is suppressed, resulting in a beautiful appearance and high gloss of the molded product.

[0081] The alkyl acrylate polymer is not particularly limited as long as it conforms to the definition of the present invention, and can be manufactured directly or a commercially available product can be used.

[0082] The styrene-acrylonitrile copolymer having a weight-average molecular weight of 30,000 to 70,000 g / mol is preferably 40,000 to 67,000 g / mol, more preferably 50,000 to 65,000 g / mol, and even more preferably 55,000 to 65,000 g / mol. Within this range, there is an effect of improving fluidity, excellent processability, and improved appearance quality.

[0083] The aforementioned styrene-acrylonitrile copolymer, having a weight-average molecular weight of 30,000 to 70,000 g / mol, may, for example, have a flow index (190°C, 5 kg) measured in accordance with ISO 1133 of 20 to 60 g / 10 min, preferably 25 to 55 g / 10 min. Within this range, it exhibits excellent impact strength and flowability, as well as superior appearance quality.

[0084] The aforementioned styrene-acrylonitrile copolymer, having a weight-average molecular weight of 30,000 to 70,000 g / mol, may, for example, have a heat distortion temperature of 82 to 90°C, preferably 84 to 88°C, as measured in accordance with ASTM D648. Within this range, it exhibits excellent impact strength and fluidity, as well as superior appearance quality.

[0085] The ethylene copolymer may be, for example, one or more selected from the group consisting of ethylene / 1-butene copolymer and ethylene / n-butyl acrylate / carbon monoxide ternary copolymer. In this case, it has the effect of having excellent heat resistance and fluidity, as well as excellent appearance quality.

[0086] The olefin-based wax may, for example, be one or more selected from the group consisting of polyethylene wax and polypropylene wax, and preferably polyethylene wax. In this case, it has the effect of having excellent heat resistance and fluidity, and excellent appearance quality.

[0087] The aliphatic amide compound may be one or more selected from the group consisting of, for example, stearamide, behenamide, ethylene bis(stearamide), N,N'-ethylene bis(12-hydroxystearamide), erucamide, oleamide, and ethylene bis oleamide. Preferably, it may be ethylene bis(stearamide), in which case it has the effect of having excellent impact strength and fluidity, and excellent appearance quality.

[0088] The aforementioned antioxidant may be selected, for example, from one or more copper-based compounds and potassium-based compounds. In this case, it has the effect of having excellent heat resistance retention and discoloration resistance.

[0089] The copper-based compound may, for example, be CuI, and the potassium-based compound may, for example, be one or more selected from the group consisting of KI, KBr, etc.

[0090] As an example, the antioxidant may be present in an amount of 5% by weight or less, preferably 0.1 to 5% by weight, of the total 100% by weight of the polyamide resin composition. Within this range, by reducing the thermal history that the polymer material experiences during thermoforming processes such as extrusion and injection, it is possible to improve the retention of physical properties while also providing excellent colorfastness.

[0091] The heat stabilizer may be, for example, one or more selected from the group consisting of phenolic heat stabilizers, phosphite heat stabilizers, and thioether heat stabilizers, and is preferably a phenolic heat stabilizer and a phosphite heat stabilizer.

[0092] The heat stabilizer may, for example, be present in an amount of 0.1 to 2.5% by weight, preferably 0.3 to 1.5% by weight, and more preferably 0.3 to 1% by weight, of 100% by weight of the total polyamide resin composition. In this case, the heat resistance is improved.

[0093] The phenolic heat stabilizer may be one or more selected from the group consisting of, for example, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, 1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, and 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione.

[0094] The phosphite-based heat stabilizer may, for example, be trisnonylphenyl phosphite, tris-(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, or a mixture thereof.

[0095] The thioether-based heat stabilizer may, for example, be one or more selected from the group consisting of dilauryl thiodipropionate, dimyristyl thiodipropionate, lauryl stearyl thiodipropionate, distearyl thiodipropionate, dimethyl thiodipropionate, 2-mercaptobenzimidazole, phenothiazine, octadecyl thioglycolate, butyl thioglycolate, octyl thioglycolate, and thiocresol.

[0096] The light stabilizer may, for example, be present in an amount of 0.1 to 2.5% by weight, preferably 0.3 to 1.5% by weight, and more preferably 0.3 to 1% by weight, of the total 100% by weight of the polyamide resin composition. In this case, the weather resistance is improved.

[0097] The aforementioned light stabilizer may, for example, be a hindered amine light stabilizer (HALS), preferably 1,1-bis(2,2,6,6-tetramethyl-4-piperidyl) succinate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, or bis(1,2,2,6,6-pentamethyl-4-piperidyl)-N-butyl-3,5-di-tert-butyl-4-hydroxyben Dilmalonate, condensation product of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensation product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-di-chloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-buta Ntetracarboxylate, 1,1'-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, linear or cyclic condensation product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3, One or more selected from the group consisting of the reaction product of 8-diaza-4-oxospiro-[4,5]decane and epichlorohydrin, and poly[[6-(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino], more preferably bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (Bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, poly[[6-(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino], or these It may be a mixture, more preferably bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly[[6-(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino], or a mixture thereof, which has the advantage of not impairing impact resistance and fluidity, and greatly improving weather resistance.

[0098] When the aforementioned heat stabilizer and light stabilizer are included, there is the advantage that the synergistic effect of their combination further improves heat aging resistance.

[0099] The polyamide resin composition may optionally further contain one or more substances selected from the group consisting of flame retardants, hydrolysis stabilizers, dyes, pigments, colorants, antistatic agents, crosslinking agents, antimicrobial agents, processing aids, and carbon black masterbatches, in an amount of 0.1 to 2.5% by weight, preferably 0.3 to 1.5% by weight, and more preferably 0.3 to 1% by weight, per 100% by weight of the total polyamide resin composition. Within this range, the desired physical properties are achieved without degrading the inherent physical properties of the polyamide resin composition described herein.

[0100] Polyamide resin composition The polyamide resin composition described herein is characterized by exhibiting whitening-free properties on the surface of an ISO bending test specimen, which was manufactured under temperature conditions of 280 to 310°C and then aged for 4 weeks under high temperature and high humidity conditions of 70°C and 62RH%.

[0101] Here, "whitening" refers to the phenomenon where, when a product is left for a long period of time in a high-temperature, high-humidity environment of 70°C and 62RH, a migration phenomenon occurs on the surface of the product, resulting in the observation of white spots on the surface. According to this description, such a whitening phenomenon is not observed, and the product has an excellent balance of all physical properties and superior heat resistance stability, resulting in improved surface quality and expected lifespan.

[0102] The aforementioned polyamide resin composition may have a tensile strength of, for example, 170 MPa or higher, more preferably 180 MPa or higher, and even more preferably 190-220 MPa, measured in accordance with ISO 527 under conditions of a gauge length of 50 mm, a test speed of 5.0 mm / min, and a test speed of 23°C. Within this range, it has the advantage of having an excellent balance of physical properties, as well as excellent heat resistance, rigidity, and impact resistance.

[0103] The aforementioned polyamide resin composition, when measured in accordance with ISO 178 with a span of 64 mm and a test speed of 2.0 mm / min, may have a flexural modulus of 8,000 MPa or higher, more preferably 8,500 MPa or higher, and even more preferably 8,900 to 9,500 MPa. Within this range, it has the advantage of having an excellent balance of physical properties, as well as excellent heat resistance, rigidity, and impact resistance.

[0104] Method for producing polyamide resin composition A method for producing the polyamide resin composition described herein includes, as an example, the steps of kneading and extruding (A) a polyamide resin, (B) glass fibers, and (C) an ether compound, wherein the (C) ether compound includes an ether compound having an (C-1)OH value in the range of 35 to 40 mgKOH / g, and an ether compound having an (C-2)OH value in the range of 1190 to 1320 mgKOH / g.

[0105] As another example, the method for producing the polyamide resin composition described herein is characterized by comprising the steps of kneading and extruding (B) glass fiber 39 to 89.4% by weight, (C) glass fiber 4.4 to 40% by weight, (C) ether compound 0.5 to 10% by weight having an OH value in the range of 35 to 40 mgKOH / g, (C) ether compound 0.1 to 10% by weight having an OH value in the range of 1190 to 1320 mgKOH / g, and (D) additive 5% by weight or less.

[0106] The aforementioned kneading and extrusion may be carried out using, for example, a single-screw extruder, a twin-screw extruder, or a Banbury mixer, in which case the composition is uniformly dispersed and has excellent compatibility.

[0107] The aforementioned kneading and extrusion may, for example, be carried out within a barrel temperature range of 200 to 300°C, preferably 210 to 290°C, and more preferably 210 to 280°C. In this case, the processing rate per unit time is appropriate, sufficient melt kneading is possible, and problems such as thermal decomposition of resin components are not caused.

[0108] The aforementioned kneading and extrusion may, for example, be carried out under conditions where the screw rotation speed is 200 to 300 rpm, preferably 220 to 280 rpm, and more preferably 230 to 270 rpm. In this case, the processing amount per unit time is appropriate, resulting in excellent process efficiency while suppressing excessive cutting.

[0109] The polyamide resin composition obtained through the kneading and extrusion process may preferably be provided in pellet form.

[0110] The type of extruder is not particularly limited and can be appropriately selected as long as it is commonly used in the industry. For example, a single-screw extruder with one screw or a multi-screw extruder with multiple screws can be used. However, considering the uniform mixing of the material, ease of processing, and economic efficiency, it is preferable to use a twin-screw extruder with two screws.

[0111] The extruder comprises a feeder for supplying material into a barrel, a screw for transporting and kneading the material supplied into the barrel, and a die for extruding the kneaded material. The screw is composed of multiple screw elements to provide various functions.

[0112] The raw material feeder may consist of one or more, and may be selectively provided with two or more as needed. For example, it may be provided with a main inlet and optionally an auxiliary inlet, and may have two or more auxiliary inlets as needed.

[0113] The kneading block of the present invention is an example of the screw element, and specifically consists of a plurality of disks, preferably 3 to 7, 5 to 7, 3 to 5, or 4 to 5 disks, which usually have a polygonal or elliptical cross-section and are arranged continuously in the direction of material transport. Furthermore, the phase angle of the disks in the kneading block (meaning the angle of movement between disks) is preferably 45 to 90°.

[0114] Furthermore, kneading blocks include forward kneading blocks that have the ability to transport, distribute, and mix materials; neutral kneading blocks that have the ability to distribute and mix materials but not the ability to transport them; and backward kneading blocks that transport materials in the opposite direction to the transport direction.

[0115] molded product The molded article described herein is characterized, for example, by containing the polyamide resin composition described herein, and in this case, has the advantage of having superior heat aging resistance compared to conventional polyamide resin compositions.

[0116] The method for manufacturing a molded article described herein is characterized by including a step of injecting an extruded product manufactured by the method for manufacturing the polyamide resin composition, and in such a case, there is the advantage that a molded article having rigidity, impact resistance and heat resistance simultaneously can be easily manufactured.

[0117] The injection temperature (cylinder temperature) during injection is preferably 250 to 300°C, more preferably 260 to 290°C, and within this range, there is the advantage that injection-molded products requiring complex designs can be easily manufactured.

[0118] The injection pressure is preferably 20 to 90 bar, more preferably 40 to 80 bar, and within this range, there is the advantage that injection molded products requiring complex designs can be easily manufactured.

[0119] The holding pressure during injection may preferably be 20 to 80 bar, and more preferably 30 to 60 bar. Within this range, there is the advantage that injection molded products with complex designs can be easily manufactured.

[0120] The molded product may be a product for applications requiring rigidity, impact resistance, and heat resistance.

[0121] The molded product may be an automotive part or an electrical / electronic component.

[0122] The aforementioned molded product may, for example, be an engine cover, under cover, intercooler, AIM, manifold, etc., and in this case, the polyamide resin composition described herein has the advantage of being able to provide a product of a quality exceeding the quality required by the market.

[0123] In describing the polyamide resin compositions, their manufacturing methods, and molded articles described herein, it is explicitly stated that other conditions and equipment not explicitly mentioned may be selected as appropriate within the range of practices commonly used in the industry, and are not particularly limited.

[0124] The following are preferred embodiments to aid in understanding the present invention. However, these embodiments are merely illustrative of the present invention, and it will be obvious to those skilled in the art that various changes and modifications are possible within the scope of the present invention and the technical concept, and that such changes and modifications fall within the scope of the appended claims.

[0125] [Examples] The components used in the following examples and comparative examples are as follows: *A1) Polyamide: Amorphous 50-60% by weight, melting point (Tm) 259-261°C, relative viscosity (RV) 2.4 *A2) Polyamide: Amorphous 50-60% by weight, melting point (Tm) 220°C, relative viscosity (RV) 2.5 *(B) Glass fiber: Contains 52-56 wt% silica, 12-16 wt% alumina, 21-25 wt% calcium oxide and magnesia (where magnesia is 1.5 wt% or less), 1 wt% or less titanium dioxide, 5-8 wt% boron oxide, and less than 2.0 wt% of the remainder including sodium oxide, potassium oxide and iron oxide, and has a tensile modulus of 83-87 GPa measured in accordance with ASTM D2343 for a 17 μm, 2400 tex roving strand, aspect ratio 1:4 (L / D, D: 7 μm), non-circular, flat type, high rigidity glass fiber. *(C-1) Ether compound: PTMG 3000, which has 37 mg KOH / g of hydroxyl groups. *(C-2) Ether compound: Dipentaerythritol (DPE) with an OH value of 1190-1320 mgKOH / g *(D) Additive - Additive 1: Lubricant (Clariant's LICOWAX-OP product was used.) - Additive 2: Antioxidant (KI and CuI products were used.)

[0126] Examples 1-2 and Comparative Examples 1-5 The components and content listed in Table 1 below were melt-mixed and extruded into pellets using a twin-screw extruder [SM T40] with a temperature of 250°C, a rotation speed of 250 rpm, and an F / R of 60 kg / h. These pellets were then used to produce evaluation test specimens using an injection molding machine [Engel, 80 tons].

[0127] The twin-screw extruder had a total of two or more inlets. All components were fed into the main inlet, and additives 1 and 2 were added at a total of 0.6% by weight (0.3% by weight and 0.3% by weight, respectively).

[0128] [Example Test] The properties of the test specimens produced in Examples 1-2 and Comparative Examples 1-5 were measured by the following method, and the results are shown in Table 1 below. *Specific gravity (g / cm 3 ): Measured in accordance with ISO 1183. *Tensile strength (MPa): Measured in accordance with ISO 527, under conditions of a gauge length of 50 mm, a test speed of 5.0 mm / min, and 23°C. * Flexural modulus (MPa): Measured in accordance with ISO 178, with a span of 64 mm and a test speed of 2.0 mm / min. *Tensile strength retention rate against heat aging (%): Tensile strength was measured in accordance with ISO 527 for test specimens before and after aging at 200°C for 1000 hours, and calculated using Formula 1 below.

[0129] [Formula 1] Heat aging tensile strength retention rate (%) = [Tensile strength after aging / Tensile strength before aging] × 100

[0130] *Color L value: The color L value of test specimens was measured in accordance with ISO 7724 / 1 after aging at 70°C and 62RH for 4 weeks.

[0131] [Table 1]

[0132] As shown in Table 1 above, the polyamide resin compositions according to the present invention (Examples 1 and 2) were found to be far superior in all measured items, including tensile strength, flexural modulus, heat aging tensile strength retention rate, and appearance evaluation of test specimens based on heat stability, compared to polyamide resin compositions outside the scope of the present invention (Comparative Examples 1 to 5), in all examples.

[0133] On the other hand, in Comparative Example 1, where the (C-1) ether compound was not used, it was confirmed that the appearance of the test specimen was significantly worse compared to Example 1 due to a deterioration in heat resistance stability.

[0134] Furthermore, in Comparative Example 2, which used a small amount of (C-1) ether compound, it was confirmed that the appearance of the test specimen was significantly worse compared to Example 1, due to a deterioration in the retention rate of tensile strength against heat aging and the thermal stability.

[0135] Furthermore, in Comparative Example 3, where an excess of the (C-1) ether compound was used, it was confirmed that the flexural modulus, heat-resistant tensile strength retention rate, and appearance of the test specimens due to heat stability were significantly worse compared to Example 1.

[0136] Furthermore, in Comparative Example 4, which used a small amount of (C-2) ether compound, it was confirmed that the tensile strength, heat aging tensile strength retention rate, and appearance of the test specimens due to heat stability were significantly worse compared to Example 1.

[0137] Furthermore, in Comparative Example 5, where an excess of the (C-2) ether compound was used, it was confirmed that the specific gravity and tensile strength of the test specimens were significantly worse compared to Example 1.

[0138] In conclusion, when a polyamide resin composition is produced by mixing polyamide resin, glass fibers, and an ether compound satisfying a specific OH value in a predetermined composition ratio, it was confirmed that molded articles containing such a polyamide resin composition exhibit excellent tensile strength and flexural modulus, as well as excellent heat aging resistance, and are virtually unaffected by heat and other influences from exposure to the external environment, making them suitable for automotive parts or electrical and electronic components.

Claims

1. (A) Polyamide resin, (B) Glass fiber, and (C) Ether compound are included. The polyamide resin composition is characterized in that the (C) ether compound comprises an ether compound having a (C-1)OH value in the range of 35 to 40 mgKOH / g, and an ether compound having a (C-2)OH value in the range of 1190 to 1320 mgKOH / g.

2. A polyamide resin composition characterized by comprising: (A) 39 to 89.4% by weight of polyamide resin; (B) 4.4 to 40% by weight of glass fiber; (C-1) 0.5 to 10% by weight of an ether compound having an OH value in the range of 35 to 40 mgKOH / g; (C-2) 0.1 to 10% by weight of an ether compound having an OH value in the range of 1190 to 1320 mgKOH / g; and (D) 5% by weight or less of an additive.

3. The polyamide resin composition according to claim 1 or 2, characterized in that the (C-1) ether compound has a number average molecular weight in the range of 2600 to 3200 g / mol, and the (C-2) ether compound has a number average molecular weight in the range of 100 to 400 g / mol.

4. The polyamide resin composition according to claim 1 or 2, characterized in that the (C-1) ether compound and the (C-2) ether compound are contained in a weight ratio of 1:0.5 to 1:5 (C-1:C-2).

5. The polyamide resin composition according to claim 1 or 2, characterized in that the glass fibers contain 52 to 56% by weight of silica, 12 to 16% by weight of alumina, 21 to 25% by weight of calcium oxide and magnesia (where magnesia is 1.5% by weight or less), 1% by weight or less of titanium dioxide, 5 to 8% by weight of boron oxide, and a remainder of less than 2.0% by weight of sodium oxide, potassium oxide and iron oxide.

6. The polyamide resin composition according to claim 2, characterized in that the additive is one or more selected from lubricants, antioxidants, heat stabilizers, and light stabilizers.

7. The polyamide resin composition according to claim 1 or 2, characterized in that the tensile strength measured in accordance with ISO 527 under conditions of a gauge length of 50 mm, a test speed of 5.0 mm / min, and 23°C is 170 MPa or more, and the flexural modulus measured in accordance with ISO 178 under conditions of a span of 64 mm and a test speed of 2.0 mm / min is 8,800 MPa or more.

8. A method for producing a polyamide resin composition, comprising the steps of kneading and extruding (A) a polyamide resin, (B) glass fibers, and (C) an ether compound, wherein the (C) ether compound includes an ether compound having a (C-1)OH value in the range of 35 to 40 mgKOH / g and an ether compound having a (C-2)OH value in the range of 1190 to 1320 mgKOH / g.

9. A method for producing a polyamide resin composition, characterized by kneading and extruding the following: (A) 39 to 89.4% by weight of polyamide resin, (B) 4.4 to 40% by weight of glass fiber, (C-1) 0.5 to 10% by weight of an ether compound having an OH value in the range of 35 to 40 mgKOH / g, (C-2) 0.1 to 10% by weight of an ether compound having an OH value in the range of 1190 to 1320 mgKOH / g, and 0 to 5% by weight of an additive.

10. A molded article characterized by comprising the polyamide resin composition described in claim 1.

11. The molded article according to claim 10, characterized in that the molded article is an automobile part or an electrical / electronic component.

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