JP7387248B2 - polyamide resin composition - Google Patents

Description

The present invention relates to polyamide resin compositions.

Polyamide resin can achieve high rigidity etc. by blending it with glass fiber. However, since glass fibers have a property of being oriented in the flow direction of the resin, anisotropy in strength occurs, which may cause warping. As a technique for achieving low warpage, a technique of blending glass fibers with a flat cross section has been proposed (see, for example, Patent Documents 1 and 2). In addition, as a technology to achieve high vibration resistance, a glass fiber-reinforced polyamide resin composition has been proposed in which glass fibers with a specific cross-sectional area are combined with aliphatic polyamide and polymethaxylene adipamide (for example, a patented (See Reference 3).

Japanese Patent Application Publication No. 10-219026 International Publication No. 2008/120703 International Publication No. 2014/171363

However, with the conventional techniques, it is sometimes difficult to maintain high rigidity and low warpage while achieving a good surface appearance when forming a molded product.
An object of the present invention is to provide a polyamide resin composition that can achieve high rigidity, low warpage, and good surface appearance in a molded article.

Specific means for solving the above problem are as follows.
Contains a polyamide resin (A) and glass fiber (B), the polyamide resin (A) includes one type of crystalline polyamide resin (A-1) and an amorphous polyamide resin (A-2), The glass fiber (B) is a polyamide resin composition containing glass fibers (B-1) with a non-circular cross section, and the total content of the glass fibers (B) is 40% by mass or more and 80% by mass or less.

According to the present invention, it is possible to provide a polyamide resin composition that can realize high rigidity, low warpage, and good surface appearance in a molded article.

In this specification, when there are multiple substances corresponding to each component in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition. means.

[Polyamide resin composition]
The polyamide resin composition of the present embodiment includes a polyamide resin (A) and a glass fiber (B), and the polyamide resin (A) is composed of a crystalline polyamide resin (A-1) and a temperature of 275° C. based on ISO1133. an amorphous polyamide resin (A-2) whose MVR measured at a load of 5 kg is 50 ml/10 minutes or more, and the glass fiber (B) includes a glass fiber (B-1) with a non-circular cross section, The total content of the glass fibers (B) is 40% by mass or more and 80% by mass or less. A molded product is formed by blending a non-circular cross-section glass fiber (B-1) with a crystalline polyamide resin (A-1) and a specific amorphous polyamide resin (A-2) at a specific content. In this case, a good surface appearance can be achieved while maintaining high rigidity and low warpage.

Polyamide resin (A)
The polyamide resin composition includes at least one type of crystalline polyamide resin (A-1) as the polyamide resin, and an amorphous polyamide having an MVR of 50 ml/10 minutes or more when measured at a temperature of 275°C and a load of 5 kg based on ISO1133. and at least one type of resin (A-2). By combining the crystalline polyamide resin (A-1) and the amorphous polyamide resin (A-2) having a specific MVR value, molded products can be produced in good condition while maintaining high rigidity and low warpage. A unique surface appearance can be achieved.

Crystalline polyamide resin (A-1)
In this specification, the crystalline polyamide resin (A-1) refers to a polyamide resin that exhibits a clear endothermic peak due to melting in differential scanning calorimeter (DSC) analysis under heating conditions of 10°C/min. Specifically, it means a polyamide resin having a heat of crystal fusion of more than 1 cal/g.

Examples of the crystalline polyamide resin (A-1) include aliphatic polyamide resins made of aliphatic diamines and aliphatic dicarboxylic acids, aliphatic polyamide resins made of lactams or aminocarboxylic acids, and the like. The crystalline polyamide resin (A-1) is preferably an aliphatic polyamide resin.

The monomer components constituting the aliphatic polyamide resin include an aliphatic diamine having 2 to 20 carbon atoms, preferably 4 to 12 carbon atoms, and an aliphatic dicarboxylic acid having 2 to 20 carbon atoms, preferably 6 to 12 carbon atoms. combinations, lactams having 6 to 12 carbon atoms, aminocarboxylic acids, and the like.

Examples of aliphatic diamines include ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, peptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, Examples include tetradecane diamine, pentadecane diamine, hexadecane diamine, heptadecane diamine, octadecane diamine, nonadecane diamine, eicosane diamine, and the like. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, and tetradecanedione. acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosandioic acid, and the like.

Examples of the combination of aliphatic diamine and aliphatic dicarboxylic acid include a combination of hexamethylene diamine and adipic acid, a combination of hexamethylene diamine and sebacic acid, a combination of hexamethylene diamine and dodecanedioic acid, etc. Salt is preferably used.

Examples of the lactam include ε-caprolactam, enantholactam, undecanelactam, dodecanelactam, α-pyrrolidone, α-piperidone, and the like. Further, examples of aminocarboxylic acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Among these, from the viewpoint of polymerization production, at least one selected from the group consisting of ε-caprolactam, undecanelactam, and dodecanelactam is preferred.

The monomer components constituting the aliphatic polyamide resin may be used alone or in combination of two or more. Here, the combination of an aliphatic diamine and an aliphatic dicarboxylic acid is considered to be a combination of one type of aliphatic diamine and one type of aliphatic dicarboxylic acid as one type of monomer component.

From the viewpoint of productivity, the crystalline polyamide resin (A-1) is polyamide 6, polyamide 66, polyamide 6/66, polyamide 6/12, polyamide 610, polyamide 612, polyamide 6/66/12, polyamide 11, and polyamide. 12, more preferably polyamide 6 and/or polyamide 66.
The crystalline polyamide resin (A-1) may contain one type alone or a combination of two or more types. When two or more types of crystalline polyamide resins are included, the total content of other crystalline polyamide resins relative to the crystalline polyamide resin having the largest content is, for example, 25% by mass or less, preferably 5% by mass or less.

The relative viscosity of the crystalline polyamide resin (A-1) is not particularly limited, but the relative viscosity measured at 25°C for the crystalline polyamide resin (A-1) at a concentration of 1% in 98% sulfuric acid according to JIS K 6810 It is preferable that the viscosity is 1.8 or more and 5.0 or less.

From the viewpoint of mechanical properties and surface appearance, the content of the crystalline polyamide resin (A-1) in the total amount of the polyamide resin composition is preferably, for example, 20% by mass or more and less than 60% by mass, and 30% by mass or more and less than 50% by mass. The following are more preferable.

Amorphous polyamide resin (A-2)
In this specification, the amorphous polyamide resin (A-2) means a polyamide resin in which almost no crystallization occurs or the crystallization rate is very low. Specifically, it means a polyamide resin that does not show a clear endothermic peak due to melting in a differential scanning calorimeter (DSC) analysis under a temperature increase condition of 10°C/min, and has a crystal fusion heat of 1 cal/g or less. It means something.
Further, the amorphous polyamide resin (A-2) has an MVR of 50 ml/10 minutes or more, preferably 60 ml/10 minutes or more, as measured in accordance with ISO 1133 at a temperature of 275° C. and a load of 5 kg. If the MVR is less than 50 ml/10 minutes, it may be difficult to achieve a good surface appearance in the molded article. The upper limit of MVR is, for example, 200 ml/min, preferably 100 ml/min.
In addition, when two or more types of amorphous polyamide resin are included, the MVR of the amorphous polyamide resin as a whole is measured by mixing them, and the MVR measured at a temperature of 275°C and a load of 5 kg based on ISO1133 is 50 ml/10 minutes. In the above case, the entire amorphous polyamide resin can be made into the amorphous polyamide resin (A-2). It is preferable to measure MVR according to the above contents, but if the MVR of each amorphous polyamide resin and its mixing ratio are known, the values obtained by multiplying each MVR by the mixing ratio are summed. The average value calculated can be taken as the MVR of the entire amorphous polyamide resin.

The amorphous polyamide resin (A-2) is preferably a polyamide resin having a structure that inhibits crystallization. Alternatively, polyamides having side chains can be mentioned. Further, from the viewpoint of inhibiting crystallization, a copolymer is more preferable. The amorphous polyamide resin (A-2) is preferably a copolyamide resin containing at least two aromatic monomer components, for example, and the peak temperature of the loss modulus during bone drying obtained by measuring dynamic viscoelasticity. It is more preferable that the glass transition temperature determined by is 100° C. or higher. The method of polymerizing the amorphous polyamide may be any known method and is not particularly limited.

Examples of dicarboxylic acids constituting the amorphous polyamide resin (A-2) include terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, dibenzoic acid, 4,4'-oxydibenzoic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4' -dicarboxylic acid, aromatic dicarboxylic acids such as 4,4'-biphenyldicarboxylic acid; and alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid.

Examples of the diamine constituting the amorphous polyamide resin (A-2) include alicyclic diamines such as cyclohexane diamine, methylcyclohexane diamine, and isophorone diamine; p-phenylene diamine, m-phenylene diamine, p-xylene diamine, Examples include aromatic diamines such as m-xylene diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 4,4'-diaminodiphenyl ether.

Specifically, the amorphous polyamide resin (A-2) is a polycondensate of isophthalic acid/terephthalic acid/hexamethylenediamine/bis(3-methyl-4-aminocyclohexyl)methane, terephthalic acid/2,2, Polycondensate of 4-trimethylhexamethylenediamine/2,4,4-trimethylhexamethylenediamine, isophthalic acid/bis(3-methyl-4-aminocyclohexyl)methane/polycondensate of ω-laurolactam, isophthalic acid/ Terephthalic acid/hexamethylenediamine polycondensate (polyamide 6T/6I), isophthalic acid/2,2,4-trimethylhexamethylenediamine/2,4,4-trimethylhexamethylenediamine polycondensate, isophthalic acid/terephthalic acid Acid/polycondensate of 2,2,4-trimethylhexamethylenediamine/2,4,4-trimethylhexamethylenediamine, polycondensate of isophthalic acid/bis(3-methyl-4-aminocyclohexyl)methane/ω-laurolactam Examples include condensates. Among these, the amorphous polyamide resin (A-2) is preferable because a copolymer having an aromatic ring, such as polyamide 6T/6I, inhibits crystallization of the crystalline polyamide resin.

Specifically, the amorphous polyamide resin (A-2) is preferably one consisting of 40 to 95 mol% of terephthalic acid component units, 5 to 60 mol% of isophthalic acid component units, and an aliphatic diamine. Preferred combinations of monomer components constituting the amorphous polyamide resin (A-2) include equimolar salts of hexamethylene diamine and terephthalic acid and equimolar salts of hexamethylene diamine and isophthalic acid.
In addition, the amorphous polyamide resin (A-2) contains units derived from a monomer component consisting of aliphatic diamine, isophthalic acid, and terephthalic acid in an amount of 60% by mass or more and 99% by mass or less, and contains units of an aliphatic polyamide component. A copolymer containing 1% by mass or more and 40% by mass or less is preferred.

The relative viscosity of the amorphous polyamide resin (A-2) is not particularly limited, but according to JIS K 6810, the relative viscosity of the amorphous polyamide resin (A-2) at a concentration of 1% in 98% sulfuric acid at 25°C. The measured relative viscosity is preferably from 1.5 to 4.0, more preferably from 1.8 to 3.0.

From the viewpoint of mechanical properties and surface appearance, the content of the amorphous polyamide resin (A-2) in the total amount of the polyamide resin composition is preferably 0.5% by mass or more and 30% by mass or less, and 0.5% by mass. It is more preferably 20% by mass or less, more preferably 3% by mass or more and 25% by mass or less, more preferably 3% by mass or more and 20% by mass or less, even more preferably 3% by mass or more and 8% by mass or less. The polyamide resin composition may contain one type of amorphous polyamide resin or a combination of two or more types.

Glass fiber (B)
The polyamide resin composition includes at least glass fibers (B-1) having a non-circular cross section as the glass fibers (B), and the total content of the glass fibers (B) is 40% by mass or more and 80% by mass or less. As a result, a molded product can have a good surface appearance while maintaining high rigidity and low warpage.

Glass fiber with non-circular cross section (B-1)
The glass fiber (B-1) having a non-circular cross section is not particularly limited as long as it has a non-circular cross section. A non-circular cross section means that in a cross section perpendicular to the length direction of the glass fiber, the major axis connecting the two points on the outer periphery of the cross section with the maximum distance, and the outer periphery of the cross section in a straight line perpendicular to the major axis. It means a shape in which there is a short axis connecting the two points where the distance between the two points intersecting is the maximum, and the length of the long axis and the short axis are different. The ratio of the long axis of the glass fiber to the short axis may be greater than 1, and from the viewpoint of mechanical properties, for example, 1.2 or more and 10 or less, preferably 1.5 or more and 6 or less, and 1.7 or more and 4.5 or less. is more preferable.

The cross-sectional shape of the glass fiber (B-1) having a non-circular cross section is usually a cocoon shape, an ellipse, a semicircle, an arc, a rectangle, a parallelogram, or similar shapes thereof. Practically, from the viewpoint of fluidity, mechanical properties, and low warpage, a cocoon-shaped, oval, or rectangular shape is preferable. For a specific example of the cross-sectional shape of the glass fiber (B-1) having a non-circular cross-section, reference can be made to, for example, the description in JP-A-62-268612.

The thickness of the glass fiber (B-1) having a non-circular cross section is not particularly limited. The short axis of the glass fiber (B-1) with a non-circular cross section is usually 0.5 μm or more and 25 μm or less, and the long axis is usually 1.25 μm or more and 300 μm or less.
The glass fiber (B-1) with a non-circular cross section has a fiber length of usually 1 mm or more and 15 mm or less, preferably 1.5 mm or more and 12 mm or less, and more preferably 2 mm or more and 6 mm or less.
The aspect ratio obtained by dividing the fiber length by the average value of the major axis and minor axis of the glass fiber (B-1) with a non-circular cross section is usually 10 or more, and from the viewpoint of rigidity, mechanical strength, and fluidity, It is preferably 15 or more and 100 or less.

Examples of the glass constituting the glass fiber (B-1) with a non-circular cross section include those having compositions such as A glass, C glass, and E glass, and E glass is preferable from the viewpoint of thermal stability of the polyamide resin. . Further, the glass fiber (B-1) having a non-circular cross section may be surface-treated with a silane coupling agent, a titanium coupling agent, or other polymeric or low-molecular surface treatment agent. The surface treatment improves dispersibility and adhesion into the polyamide resin. Furthermore, the glass fibers (B-1) having a non-circular cross section are preferably bound with a binding material from the viewpoint of improving adhesiveness with the resin. The binding material is not particularly limited, and from the viewpoint of compatibility with the polyamide resin, it is preferably a urethane resin and/or an acrylic resin.

The content of the glass fiber (B-1) with a non-circular cross section in the total amount of the polyamide resin composition is preferably 15% by mass or more and 70% by mass or less from the viewpoint of high rigidity, low warpage, and good surface appearance. More preferably 20% by mass or more and 65% by mass or less.

Glass fiber with circular cross section (B-2)
The polyamide resin composition may further contain, as glass fibers, glass fibers (B-2) with a circular cross section in addition to the glass fibers (B-1) with a non-circular cross section. The circular cross-section glass fiber (B-2) is a glass fiber whose cross section perpendicular to the length direction of the glass fiber is circular. The average fiber diameter of the glass fiber (B-2) having a circular cross section is, for example, 4 μm or more and 15 μm or less, and more preferably 6 μm or more and 13 μm or less. When the average fiber diameter is within the above range, the mechanical properties and dimensional stability of the molded article tend to be further improved. Note that the average fiber diameter of the glass fiber (B-2) having a circular cross section can be measured according to JIS R3420.

The glass fiber (B-2) having a circular cross section has a fiber length of usually 1 mm or more and 15 mm or less, preferably 1.5 mm or more and 12 mm or less, and more preferably 2 mm or more and 6 mm or less.
The aspect ratio obtained by dividing the fiber length by the average fiber diameter of glass fibers having a circular cross section is usually 10 or more, and preferably 15 or more and 100 or less from the viewpoints of rigidity, mechanical strength, and fluidity.

Examples of the glass constituting the glass fiber having a circular cross section include those having compositions such as A glass, C glass, and E glass, and E glass is preferable from the viewpoint of thermal stability of the polyamide resin. Further, the glass fiber having a circular cross section may be surface-treated with a silane coupling agent, a titanium coupling agent, or other polymeric or low-molecular surface treatment agent. The surface treatment improves dispersibility and adhesion into the polyamide resin. Further, the glass fibers having a circular cross section are preferably bound together with a binding material from the viewpoint of improving adhesiveness with the resin. The binding material is not particularly limited, and is preferably urethane resin and/or acrylic resin from the viewpoint of compatibility with polyamide resin.

When the polyamide resin composition includes glass fibers (B-2) with a circular cross section, the content of the glass fibers (B-2) with a circular cross section in the total amount of the polyamide resin composition is 5% by mass or more and 40% by mass. From the viewpoint of high rigidity, low warpage, and good surface appearance, it is more preferably 10% by mass or more and 35% by mass or less.
In addition, the content ratio (B-2/B-1) of glass fibers with a circular cross section (B-2) and glass fibers with a non-circular cross section (B-1) provides high rigidity, low warpage, and good surface appearance. From the viewpoint, it is preferably 0.1 or more and 1.2 or less, and more preferably 0.3 or more and 1.0 or less.

The polyamide resin composition may contain other components as long as they do not impair the effects of the present invention, such as plasticizers, impact-resistant materials, heat-resistant materials, foaming agents, weathering agents, crystal nucleating agents, crystallization promoters, and mold release agents. , a lubricant, an antistatic agent, a flame retardant, a flame retardant aid, a pigment, a dye, and other functional agents may be appropriately blended.

The polyamide resin composition is prepared by mixing a crystalline polyamide resin (A-1), an amorphous polyamide resin (A-2), and a predetermined amount of glass fibers with a non-circular cross section (B-1) in a uniaxial or twin-screw extruder, Manufactured by melt-kneading using a Banbury mixer or the like.
A desired molded article can be obtained by molding the resulting polyamide resin composition. As a molding method, an extrusion molding method, a blow molding method, an injection molding method, etc. can be adopted.

The molded article containing the polyamide resin composition of the present embodiment exhibits a good surface appearance and is therefore suitably used for various purposes such as automobile parts, items requiring good design, and housings. Furthermore, the glossiness (gloss value) of a molded article obtained by injection molding a polyamide resin composition measured according to ASTM D-523 is preferably 65% or more, more preferably 70% or more.

The polyamide resin composition of this embodiment provides high rigidity, low warpage, and good surface appearance in a molded article.
(mechanical properties)
In the molded article containing the polyamide resin composition of the present embodiment, the tensile strength measured at 23° C. according to ISO527-1, 2 is preferably 265 MPa or more.
In the molded article containing the polyamide resin composition of the present embodiment, the tensile modulus measured at 23° C. according to ISO527-1, 2 is preferably 20 GPa or more.
In the molded article containing the polyamide resin composition of the present embodiment, the Charpy impact strength measured at 23° C. according to ISO 179-1 is preferably 20 kJ/m ² .
Note that the tensile strength and tensile modulus can be measured by the following method. ISO standard TYPE-A test pieces are produced by injection molding and used to obtain data on mechanical properties. The tensile strength and tensile modulus are measured at 23° C. using an Instron tensile tester model 5567 in accordance with ISO527-1,2.
Note that Charpy impact strength can be measured by the following method. In accordance with ISO179-1, Yasuda Seiki Charpy impact tester No. Using 258-PC, an edgewise impact test is performed at 23° C. using an A-notched test piece with a thickness of 4 mm. (n=10)

(Liquidity)
In the molded article containing the polyamide resin composition of this embodiment, the flow length measured under the following conditions is preferably 85 mm or more.
Using PS-40E manufactured by Nissei Jushi Kogyo Co., Ltd. (screw diameter 26 mm, mold clamping force 40 tons), a spiral flow fluidity evaluation mold with a cavity size of width w = 15 mm and thickness t = 1 mm was used. The flow length is measured from the obtained molded product. The molding conditions are a molding temperature of 290° C., a mold temperature of 80° C., and an injection pressure of 100 MPa.

(Surface appearance (gloss) (gloss))
In the molded article containing the polyamide resin composition of this embodiment, the glossiness (gloss value) measured under the following conditions is preferably 65% or more, more preferably 70% or more.
A flat plate of 100 mm x 70 mm x 2 mm thickness is prepared using SE100D-C160S manufactured by Sumitomo Heavy Industries, Ltd. (screw diameter 28 mm, mold clamping force 100 tons). The molding conditions are a molding temperature of 290° C., a mold temperature of 80° C., an injection speed of 80 mm/sec, and a cooling time of 15 seconds. The glossiness (gloss value) of the obtained test piece was measured according to ASTM D-523 using a color computer SM-5-IS-2B manufactured by Suga Test Instruments Co., Ltd. at an incident angle of 60°.

(Warp deformation)
In the molded article containing the polyamide resin composition of this embodiment, low warpage can be evaluated by the following method.
An ISO294-3 D-1 type mold of 60 mm x 60 mm x thickness of 1 ton is created using SE100D-C160S manufactured by Sumitomo Heavy Industries, Ltd. (screw diameter 28 mm, mold clamping force 100 tons). The molding conditions are a molding temperature of 290° C., a mold temperature of 80° C., an injection speed of 97 mm/sec, an injection pressure of 60 MPa, and a cooling time of 15 seconds. Immediately after molding, the gate is cut, and after being left in a moisture-proof container for 48 hours, a weight is placed on a specified corner on a surface plate, and the maximum gap with the surface plate is defined as the amount of warp deformation. If the obtained deformation amount is 3 mm or more, it is determined that there is warp deformation, and if it is less than 3 mm, it is determined that there is no warp deformation.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The methods for evaluating the physical properties of the resins and molded articles used in the Examples and Comparative Examples are shown below.

[Mechanical properties]
ISO standard TYPE-A test pieces were produced by injection molding and used to obtain data on mechanical properties. The tensile strength and tensile modulus were measured at 23° C. using an Instron tensile tester model 5567 in accordance with ISO527-1,2.

[Charpy impact strength]
In accordance with ISO179-1, Yasuda Seiki Charpy impact tester No. An edgewise impact test was conducted using 258-PC at 23° C. using an A-notched test piece with a thickness of 4 mm. (n=10)

[Liquidity]
Using PS-40E manufactured by Nissei Jushi Kogyo Co., Ltd. (screw diameter 26 mm, mold clamping force 40 tons), a spiral flow fluidity evaluation mold with a cavity size of width w = 15 mm and thickness t = 1 mm was used. The flow length of the obtained molded article was measured. The molding conditions were a molding temperature of 290°C, a mold temperature of 80°C, and an injection pressure of 100 MPa.

[Gloss]
A flat plate measuring 100 mm x 70 mm x 2 mm thick was prepared using SE100D-C160S manufactured by Sumitomo Heavy Industries, Ltd. (screw diameter 28 mm, mold clamping force 100 tons). The molding conditions were a molding temperature of 290° C., a mold temperature of 80° C., an injection speed of 80 mm/sec, and a cooling time of 15 seconds. The glossiness (gloss value) of the obtained test piece was measured according to ASTM D-523 using a color computer SM-5-IS-2B manufactured by Suga Test Instruments Co., Ltd. at an incident angle of 60°.

[Warp deformation]
An ISO 294-3 D-1 type mold 60 mm x 60 mm x thickness 1 ton was created using SE100D-C160S manufactured by Sumitomo Heavy Industries, Ltd. (screw diameter 28 mm, mold clamping force 100 tons). The molding conditions were a molding temperature of 290° C., a mold temperature of 80° C., an injection speed of 97 mm/sec, an injection pressure of 60 MPa, and a cooling time of 15 seconds. Immediately after molding, the gate was cut, and after being left in a moisture-proof container for 48 hours, a weight was placed on a specified corner on a surface plate, and the maximum gap with the surface plate was defined as the amount of warp deformation. When the obtained deformation amount was 3 mm or more, it was determined that there was warp deformation, and when it was less than 3 mm, it was determined that there was no warp deformation.

・Polyamide resin (A)
・Crystalline polyamide resin (A-1)
PA6-1: According to JIS K 6810, the relative viscosity measured at 25°C for a crystalline polyamide resin at a concentration of 1% in 96% sulfuric acid. polyamide 6
PA6-2: According to JIS K 6810, the relative viscosity measured at 25°C for a crystalline polyamide resin at a concentration of 1% in 96% sulfuric acid. polyamide 6
・Amorphous polyamide resin ・Amorphous polyamide resin (A-2) with an MVR of 50 ml/10 minutes or more when measured at a temperature of 275°C and a load of 5 kg based on ISO1133
PA6T/6I-1: Grivory G16 (manufactured by EMS-CHEMIE (Japan)) whose MVR was 100 ml/10 minutes when measured at a temperature of 275°C and a load of 5 kg based on ISO1133.
PA6T/6I-2: Grivory G21 (manufactured by EMS-CHEMIE (Japan)) whose MVR was 25 ml/10 minutes when measured at a temperature of 275°C and a load of 5 kg based on ISO1133.

・Glass fiber GF1: Glass fiber with a non-circular cross section (CSG3PA-820S manufactured by Nittobo Co., Ltd.)
Long axis to short axis ratio 4, fiber diameter 7 x 28 μm
GF2: Glass fiber with circular cross section (CS 3DE-456S manufactured by Nittobo Co., Ltd.)
Average fiber diameter 6μm
GF3: Glass fiber with circular cross section (ECS 03T-249 manufactured by Nippon Electric Glass Co., Ltd.)
Average fiber diameter 13μm

・PA6 black MB
Black masterbatch containing dye and pigment components in polyamide 6 base (UBE NYLON 1013MBC manufactured by Ube Industries, Ltd.)

・Molding aid-2
Pentalit (manufactured by Koei Chemical Industry Co., Ltd.)
・Molding aid-2
LICOWAX OP POWDER (manufactured by Clariant Japan Co., Ltd.)

・Heat resistant agent CuI, KI mixture (weight ratio 1:6)
CuI cuprous iodide F (manufactured by Ise Chemical Industry Co., Ltd.)
KI powder potassium iodide (Mitsui Fine Co., Ltd.)

Examples 1 to 9, Comparative Examples 1 to 8
The polyamide resins and glass fibers listed in Table 1 were melt-kneaded using a TEX44HCT twin-screw kneader to produce desired polyamide resin composition pellets.
Next, various test pieces were manufactured using the obtained pellets, and various physical properties were evaluated. The results obtained are shown in Table 1. In Table 1, "-" means not added.

As is clear from the results in Table 1, it can be seen that when a molded article is formed using the polyamide resin composition of the present invention, high rigidity, low warpage, and good surface appearance can be achieved.

The disclosure of Japanese Patent Application No. 2016-018653 (filing date: February 3, 2016) is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference. Incorporated herein by reference.

Claims (6)

Contains polyamide resin (A) and glass fiber (B),
The polyamide resin (A) includes a crystalline polyamide resin (A-1) and an amorphous polyamide resin having an MVR of 100 ml/10 minutes or more and 200 ml/min or less, measured at a temperature of 275° C. and a load of 5 kg based on ISO1133. (A-2),
The glass fiber (B) includes a glass fiber (B-1) with a non-circular cross section,
The total content of the glass fibers (B) is 40% by mass or more and 80% by mass or less based on the total amount of the polyamide resin composition,
The content of the amorphous polyamide resin (A-2) is 0.5% by mass or more and 8% by mass or less based on the total amount of the polyamide resin composition,
A polyamide resin composition , wherein the amorphous polyamide resin (A-2) contains polyamide 6T/6I . The polyamide resin composition according to claim 1, wherein the glass fiber (B-1) having a non-circular cross section has a ratio of the major axis to the minor axis in a cross section perpendicular to the longitudinal direction of 1.2 or more and 10 or less. The glass fiber (B) further includes:
The polyamide resin composition according to claim 1 or 2, comprising glass fibers (B-2) having a circular cross section with an average fiber diameter of 4 μm or more and 15 μm or less. The crystalline polyamide resin (A-1) is selected from the group consisting of polyamide 6, polyamide 66, polyamide 6/66, polyamide 6/12, polyamide 610, polyamide 612, polyamide 6/66/12, polyamide 11, and polyamide 12. The polyamide resin composition according to any one of claims 1 to 3 , which is selected. The polyamide resin composition according to any one of claims 1 to 4 , wherein the content of the glass fiber (B-1) having a non-circular cross section is 5% by mass or more and 70% by mass or less based on the total amount of the polyamide resin composition. A molded article comprising the polyamide resin composition according to any one of claims 1 to 5 .