JP2018070830A - Polyamide resin composition and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition that prevents its surface appearance from being changed when mold conditions are changed, while having excellent mechanical physical properties.SOLUTION: A polyamide resin composition contains (B) a glass fiber of 5-200 pts.mass relative to (A) a polyamide resin 100 pts.mass, where in (B) glass fiber 100 mass%, an Si element content is 25-28.2 mass%, and an Na element content is 0.4-2 mass%.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide resin composition and a molded body thereof.

  Polyamide resins are widely used in parts such as automobiles and electrical / electronic products because they are excellent in mechanical and thermal properties and oil resistance. Further, it is widely known that mechanical properties, heat resistance, chemical resistance and the like are greatly improved by blending glass fiber with polyamide. For this reason, it has become possible to replace conventional metal parts from the viewpoint of weight reduction and process rationalization, for example, for various electric / electronic parts, mechanical parts and automobile parts mainly for injection molding. Widely used. In recent years, the mechanical strength and heat resistance required for polyamide resin compositions have been reduced due to the downsizing of electrical and electronic parts, the complexity of shapes, the modularization of large automotive parts, and the reduction in thickness of molded products for weight reduction. Of course, it is required for polyamide resin materials that products having a constant appearance can be stably obtained even if the molding conditions are changed, in other words, molded products having an excellent appearance can be obtained under a wide range of molding conditions.

As glass fiber used for resin reinforcement etc. currently marketed, E glass of the following composition occupies most from a viewpoint of productivity, economical efficiency, and physical property balance. However, in recent years, higher mechanical strength, surface appearance and productivity than the mechanical strength, surface appearance and productivity of thermoplastic resin compositions using such E glass have been required.
SiO _2: 52~56 mass%
B ₂ O _3: 5~10 wt%
Al ₂ O ₃ : 12 to 16% by mass
CaO: 16 to 25% by mass
MgO: 0 to 6% by mass
Na ₂ O + K ₂ O: 0 to 2% by mass
TiO _2: 0 to 1.5 mass%
Fe ₂ O _3: 0~0.8 wt%
F _2: 0~1 mass%.

A glass composition (S glass) having a basic composition composed of SiO ₂ , Al ₂ O _3, and MgO is known as a glass for glass fibers that is superior in strength and elastic modulus to the E glass. About S glass, for example, the content of SiO ₂ is 57.0 to 63.0 mass%, the content of Al ₂ O ₃ is 19.0 to 23.0 mass%, and the content of MgO, based on the total mass There 10.0 to 15.0 wt%, a 4.0 to 11.0% by weight content of CaO, and _the total content of _{SiO 2, Al 2 O 3,} MgO and CaO is 99.5 A glass fiber having a composition of at least% is proposed (for example, see Patent Documents 1 and 2).

Further, as a composition excellent in fluidity and heat resistance mechanical strength by compounding with a thermoplastic resin, such as polyamide or polyester, SiO ₂ content of 57-63 wt% as S-glass, Al ₂ O ₃ content 19 to 23% by mass, CaO content is 5.5 to 11% by mass, MgO content is 10 to 15% by mass, the total of these is 99.5% by mass or more, and SiO ₂ content / a 2.7 to 3.2 at an al ₂ O ₃ content mass ratio, MgO content / CaO content is 0.9 to 2.0 in mass ratio, from 5 to 200 parts by mass of glass fibers A glass fiber reinforced thermoplastic resin composition (see, for example, Patent Document 3) has been proposed.

Special table 2009-514773 gazette International Publication No. 2011/155362 JP2015-105359A

  However, although the materials disclosed in the above-mentioned patent documents are effective in improving fluidity and strength, they have a great influence on appearance (molding condition dependency) due to changes in molding conditions, and the appearance is stable under a wide range of molding conditions. It was insufficient to obtain a molded product. An object of the present invention is to provide a polyamide resin composition that has excellent mechanical properties, has a molded article having an excellent appearance under a wide range of molding conditions, and is excellent in productivity (workability). is there.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be specifically solved by a polyamide resin composition comprising a polyamide resin and a glass fiber having a specific composition. It was.
That is, in the polyamide resin composition of the present invention, (B) glass fiber is 5 to 200 parts by mass with respect to (A) 100 parts by mass of polyamide resin, and (B) Si element content in 100% by mass of glass fiber. Is 25 to 28.2% by mass and the Na element content is 0.4 to 2% by mass.

(B) When glass fiber further contains Al, Mg, and Ca, (B) Si / Mg mass ratio in 100 mass% of glass fiber is 3 to 5.5, and Al / Ca mass ratio is 0. It is preferable that it is 5-1.5.
(B) Al element content in glass fiber 100 mass% is 6-12 mass%, Ca element content is 7-11 mass%, Mg element content is 3-8 mass%, Si, Al, Ca The total content of Mg and Na elements is preferably 48 to 52% by mass.

(A) The glass fiber is more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the polyamide resin.
(E) The lubricant may contain at least one selected from higher fatty acid metal salts, higher fatty acid ester waxes and higher fatty acid amides.
(B) It is preferable that the glass fiber is subjected to a coupling treatment with a silane coupling agent.

  The molded body of the present invention is formed by molding the above-described polyamide resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, the molded article with few surface appearance changes by a molding condition change can be obtained while having the outstanding mechanical property, and the polyamide resin composition excellent in productivity can be provided.

Hereinafter, the present invention will be described in detail.
In the polyamide resin composition of the present invention, (A) the polyamide resin is 5 to 200 parts by mass with respect to 100 parts by mass of the polyamide resin, and (B) the Si element content in 100% by mass of the glass fiber is It is 25-28.2 mass%, and Na element content is 0.4-2 mass%.

<(A) Polyamide resin>
The (A) polyamide resin used in the present invention is a polymer or copolymer mainly composed of amino acids, lactams or diamines and dicarboxylic acids. Representative examples of the raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, tetramethylenediamine, penta Methylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5 -Aliphatic diamines such as methylnonamethylenediamine, aromatic diamines such as metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1- Ami No-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane , Alicyclic diamines such as bis (aminopropyl) piperazine and aminoethylpiperazine, aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid Acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and other aromatic dicarboxylic acids, 1,4-cyclohexane Dicarboxylic acid, 1,3-cyclohexa Dicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-like alicyclic dicarboxylic acids such as cyclopentane dicarboxylic acid. In the present invention, two or more polyamide homopolymers or copolymers derived from these raw materials may be blended.

  (A) Specific examples of the polyamide resin include polyamide 6, polyamide 66, polyamide 46, polyamide 410, polyamide 56, polyamide 510, polyamide 610, polyamide 612, polyamide 106, polyamide 1010, polyamide 1012, polyamide 11 and polyamide. 12, Polyamide 4T, Polyamide 5T, Polyamide 6I, Polyamide 6T, Polyamide 9T, Polyamide 10I, Polyamide 10T, MXD6, MXD10, PXD6, PXD10 and a polyamide copolymer containing at least two different polyamide components among them or these A mixture etc. are mentioned.

The polyamide resin (A) in the present invention is preferably a polyamide resin having a melting point of 200 ° C to 330 ° C. By using a polyamide resin having a melting point of 200 ° C. or higher, heat resistance (deflection temperature under load) can be further improved. On the other hand, by using a polyamide resin having a melting point of 330 ° C. or lower, it is possible to suppress the decomposition of the polyamide during the production of the resin composition, and the heat resistance, high-temperature rigidity, mechanical strength of the molded product obtained from the resin composition, and Impact resistance can be further improved.
Here, the melting point of the polyamide resin (A) is 20 ° C. after the polyamide resin is cooled from the molten state to 30 ° C. at a temperature decreasing rate of 20 ° C./min in an inert gas atmosphere using a differential scanning calorimeter. It is defined as the temperature of the endothermic peak that appears when the temperature is raised to the melting point + 40 ° C. at a rate of temperature rise of / min. However, when two or more endothermic peaks are detected, the temperature of the endothermic peak having the highest peak intensity is defined as the melting point.

(A) It is preferable that the glass transition temperature of a polyamide resin is 30 to 150 degreeC. When the glass transition temperature is 30 ° C. or higher, the high-temperature rigidity, mechanical strength, and impact resistance of the molded product can be further improved. On the other hand, when the glass transition temperature is 150 ° C. or lower, a resin composition suitable for molding can be obtained by moderately suppressing the crystallization rate during molding.
Here, the glass transition temperature of (A) the polyamide resin is increased at a rate of temperature increase of 20 ° C./min after the polyamide resin is quenched with liquid nitrogen in an inert gas atmosphere using a differential scanning calorimeter. It is defined as the temperature at the midpoint of the stepped endothermic peak that appears when heated.

  Examples of the polyamide resin having a melting point of 200 ° C. to 330 ° C. and a glass transition temperature of 30 ° C. to 150 ° C. include polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 46, polyamide 410, polyamide 56, MXD6, MXD10, PXD6, PXD10 and a polyamide copolymer containing at least two different polyamide components from these groups, and at least one polyamide component selected from these groups, and polyamide 4T, polyamide 5T, polyamide 6I, Examples thereof include polyamide 6T, polyamide 9T, polyamide 10I, polyamide 10T, and a polyamide copolymer obtained by copolymerizing at least one polyamide component selected from these groups.

  (A) The relative viscosity of the polyamide resin is measured at 25 ° C. according to JIS K6920 by adjusting a 1% concentration solution (a ratio of {polyamide resin 1 g / 98% sulfuric acid 100 mL}) using 98% sulfuric acid. The measured value is preferably 1.5 to 3.5, more preferably 1.8 to 3.0. When ηr is higher than 1.5, embrittlement of the resin composition can be suppressed, and it is possible to make it difficult for drooling from the tip of the cylinder nozzle during molding. Moreover, since ηr is lower than 3.5, the melt viscosity of the resin does not become too high and the fluidity is excellent, so that the moldability is excellent.

  (A) As a method for producing a polyamide resin, for example, in the case of a polyamide having diamine and dicarboxylic acid as main raw materials, a low-order condensate is obtained by heating diamine and dicarboxylic acid or a salt thereof as raw materials, and further solidified. Examples thereof include a method of increasing the degree of polymerization by phase polymerization and / or melt polymerization. Two-stage polymerization in which the low-order condensate is once taken out and solid-phase polymerization and / or melt polymerization is performed. Following the production process of the low-order condensate, solid-phase polymerization and / or melt polymerization is performed in the same reaction vessel. Either of these may be used. Solid phase polymerization refers to a step of heating in a temperature range of 100 ° C. or higher and lower than the melting point under reduced pressure or in an inert gas, and melt polymerization refers to a step of heating to a melting point or higher under normal pressure or reduced pressure. Point to.

<(B) Glass fiber>
The polyamide resin composition of the present invention is formed by blending 5 to 200 parts by mass of (B) glass fiber with respect to 100 parts by mass of the (A) polyamide resin. Here, (B) glass fiber refers to the glass fiber with which the element content rate of Si and Na among the elements which comprise glass fiber satisfy | fills the following. In addition, the element content rate of following (1) and (2) is based on 100 mass% of glass fiber.
(1) Si element content: 25 to 28.2 mass%
(2) Na element content: 0.4-2 mass%

Moreover, it is preferable from the viewpoint of improving both the mechanical strength and the appearance that the element content other than the above in the elements constituting the glass fiber is in the following range. The element content described in the following (3) to (6) is also based on 100% by mass of the glass fiber.
(3) Al element content: 6 to 12% by mass
(4) Ca element content: 7 to 11% by mass
(5) Mg element content: 3 to 8% by mass
(6) Total of Si, Al, Ca, Mg, Na element ratio: 48 to 52% by mass or more

Further, (1) to (5) are more preferably in the following ranges.
(1) Si element content: 25 to 27.0 mass%
(2) Na element content: 0.8 to 2.0 mass%
(3) Al element content: 6 to 12% by mass
(4) Ca element content: 7 to 11% by mass
(5) Mg element content: 3 to 8% by mass

Further, (1) to (5) are more preferably in the following ranges.
(1) Si element content: 25.0 to 26.5 mass%
(2) Na element content: 0.8 to 1.5 mass%
(3) Al element content: 7.5 to 11% by mass
(4) Ca element content: 7 to 10% by mass
(5) Mg element content: 4 to 7.5% by mass

Alternatively, among the above elements, the Si / Mg mass ratio is preferably 3 to 5.5, more preferably 3 to 5, and still more preferably 3.5 to 5.
The Al / Ca mass ratio is preferably 0.5 to 1.5, and more preferably 0.6 to 1.4.

The Si / Al mass ratio is preferably 2 to 5, more preferably 2 to 4, and still more preferably 2 to 3.5.
The Mg / Ca mass ratio is preferably 0.3 to 1.5, and more preferably 0.5 to 1.2.
The Al / Mg mass ratio is preferably 0.5 to 4, and more preferably 0.5 to 2.5.

  In the (B) glass fiber used in the present invention, the above elements are present not as simple substances but as oxides thereof. Therefore, (B) glass fiber contains oxygen in addition to the above elements. In addition to the above, the (B) glass fiber used in the present invention may contain elements such as B, K, Fe, Ti, Zr, Zn, Mo, Mn, and Cr. (B) In glass fiber, elements other than Si, Na, Al, Mg, Ca, and O may be contained in 0.2% by mass or less in 100% by mass of (B) glass fiber. Among them, the content of B element is preferably 0.1% by mass or less, and more preferably 0.01% by mass or less.

  In the polyamide resin composition of the present invention, the blending amount of (B) glass fiber is 5 to 200 parts by mass with respect to 100 parts by mass of (A) polyamide resin. (B) When the compounding quantity of glass fiber is 5 mass parts or more, the mechanical strength and heat resistance of the molded article obtained from a resin composition can be improved. Preferably it is 10 mass parts or more, More preferably, it is 25 mass parts or more, More preferably, it is 50 mass parts or more. On the other hand, when the blending amount of (B) glass fiber is 200 parts by mass or less, the fluidity can be maintained and the surface appearance of the molded product can be improved. Preferably it is 190 mass parts or less, More preferably, it is 180 mass parts or less.

  As (B) glass fiber mix | blended with the polyamide resin composition of this invention, if the above-mentioned element content rate is satisfy | filled, there will be no restriction | limiting in particular in a fiber diameter or length, For example, an average fiber diameter is 5-5. Any of 30 μm chopped strands, rovings, and milled fibers may be used. In the case of using chopped strands, the cut length may be appropriately selected within the range of 0.1 to 6 mm.

  The glass fiber (B) used in the present invention is preferably treated with an epoxy-based, urethane-based, acrylic-based coating agent or sizing agent, and its surface is coupled with a coupling agent. May be. Examples of the coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, and γ-anilinopropyl. Silane coupling agents such as trimethoxysilane, hydroxypropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, vinylacetoxysilane, isopropyltrisisostearoyl titanate, isopropyltris (dioctylpyrophosphate) titanate, tetraoctylbis (ditridecyl) Phosphite) titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyl tridecylbenzenesulfonyl titanate, isopropyl tri (dioctyl Examples thereof include titanium coupling agents such as (tylphosphate) titanate and aluminum coupling agents such as acetoalkoxyaluminum diisopropylate. Two or more of these may be used. Of these, silane coupling agents are preferably used. (B) The glass fiber used in the present invention has a higher Si ratio compared to the conventional E glass, so that it is possible to further increase the affinity with the polyamide resin due to the synergistic effect with the silane coupling agent, The characteristics of the molded product can be further improved.

  In the polyamide resin composition of the present invention, a lubricant, a heat stabilizer, a colorant, etc., depending on the purpose, in addition to the specific (A) polyamide resin and (B) glass fiber, as long as the effects of the present invention are not impaired. It is possible to further blend these various additives and other resins.

<Lubricant>
Examples of the lubricant include, but are not limited to, higher fatty acid metal salts, higher fatty acid ester waxes, higher fatty acid amides, and the like.
A higher fatty acid metal salt is a metal salt of a higher fatty acid. As the metal element of the metal salt, from the viewpoint of higher fatty acid metal salt stability, Group 1, 2, 3 elements of the periodic table of elements, zinc, aluminum, etc. are preferable, such as calcium, sodium, potassium, magnesium, etc. , Group 1 and 2 elements, and aluminum are more preferred.
Examples of the higher fatty acid metal salt include, but are not limited to, calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, and calcium palmitate. .
Among these, from the viewpoint of releasability, a metal salt of montanic acid and a metal salt of stearic acid are preferable.

  The higher fatty acid ester wax is an esterified product of higher fatty acid and alcohol. The higher fatty acid ester wax is preferably an ester of an aliphatic carboxylic acid having 14 or more carbon atoms and an aliphatic alcohol having 14 carbon atoms from the viewpoint of releasability. Examples of the aliphatic alcohol include, but are not limited to, stearyl alcohol, behenyl alcohol, and lauryl alcohol. Examples of the higher fatty acid ester include, but are not limited to, stearyl stearate and behenyl behenate.

A higher fatty acid amide is an amide compound of a higher fatty acid.
Examples of higher fatty acid amides include, but are not limited to, stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearyl amide, ethylene bisoleyl amide, N-stearyl stearic acid amide, N-stearyl. Examples include erucic acid amide.
The higher fatty acid amide is preferably stearic acid amide, erucic acid amide, ethylene bisstearyl amide, and N-stearyl erucic acid amide, more preferably ethylene bisstearyl amide and N-stearyl from the viewpoint of releasability. Erucic acid amide.

  These higher fatty acid metal salts, higher fatty acid ester waxes, and higher fatty acid amides may be used alone or in combination of two or more.

<Heat stabilizer>
In the polyamide resin composition of the present invention, the heat described later may be added to the polyamide resin composition of the present invention for the purpose of thermal deterioration, prevention of discoloration during heat, heat aging resistance, and weather resistance, as long as the purpose of the present invention is not impaired. Stabilizers may be added.
Examples of the heat stabilizer include, but are not limited to, copper compounds such as copper acetate and copper iodide; phenol-based stabilizers such as hindered phenol compounds; phosphite-based stabilizers; hindered amine-based stabilizers. A triazine stabilizer; and a sulfur stabilizer.
One of these heat stabilizers may be used alone, or two or more thereof may be used in combination.

<Colorant>
You may add a coloring agent to the polyamide resin composition of this invention in the range which does not impair the objective of this invention as needed.
Examples of the colorant include, but are not limited to, dyes such as nigrosine, pigments such as titanium oxide and carbon black; aluminum, colored aluminum, nickel, tin, copper, gold, silver, platinum, iron oxide Metal particles such as stainless steel and titanium; pearl pigments made of mica; metallic pigments such as color graphite, color glass fiber, and color glass flakes.

<Other resins>
If necessary, the polyamide resin composition of the present invention may be blended with other resins as long as the object of the present invention is not impaired.
Such other resin is not particularly limited, and examples thereof include a thermoplastic resin described later.

Examples of the thermoplastic resin include, but are not limited to, polystyrene systems such as atactic polystyrene, isotactic polystyrene, syndiotactic polystyrene, AS (acrylonitrile styrene) resin, and ABS (acrylonitrile butadiene styrene) resin. Resins; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polyether resins such as polycarbonate, polyphenylene ether, polysulfone and polyethersulfone; Condensation resins such as polyphenylene sulfide and polyoxymethylene; Polyacrylic acid and polyacrylic acid Acrylic resins such as esters and polymethyl methacrylate; Polyolefin resins such as polyethylene, polypropylene, polybutene, and ethylene-propylene copolymers; Polyvinyl chloride And halogen-containing vinyl compound resins such as polyvinylidene chloride; phenol resins; epoxy resins and the like.
One type of these thermoplastic resins may be used alone, or two or more types may be used in combination.

The method for producing the polyamide resin composition of the present invention is not particularly limited, and the above (A) polyamide resin, (B) glass fiber and various additives used as necessary may be mixed and kneaded. Good. In that case, there is no restriction | limiting in particular in a mixing | blending, kneading | mixing method, and order, Mixing is performed with a normally used mixer, for example, a Henschel mixer, a tumbler, a ribbon blender, etc. As the kneader, a single-screw or twin-screw extruder is generally used. The raw material supply method to the melt kneader is not particularly limited, but the glass fiber is preferably blended using a side feeder or the like after the resin component is melted from the viewpoint of preventing breakage. Usually, a pellet made of the polyamide resin composition of the present invention is first produced by such an extruder, and the pellet is molded into an arbitrary shape by compression molding, injection molding, extrusion molding, or the like, to obtain a desired molded body. (Resin product).
The injection molding conditions are not particularly limited, and examples thereof include a molding method in which the molding temperature is in the range of 250 ° C. to 310 ° C. and the mold temperature is in the range of 40 ° C. to 120 ° C.

  The polyamide resin composition and molded product thereof of the present invention are utilized for various applications such as automobile parts, electrical / electronic parts, building materials, sports equipment, various containers, daily necessities, daily life goods and hygiene goods, taking advantage of their excellent characteristics. be able to.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.
(1) The evaluation method is as follows.

[Surface gloss]
Made by TOSHIBA MACHINE Co., Ltd .; using a PS40E injection molding machine at a cylinder temperature of 300 ° C. and a mold temperature of 100 ° C., so that the filling time is about 0.5 seconds or 1.5 seconds, respectively. The speed was appropriately adjusted to obtain a 60 × 60 × 3 mm injection molded plate. Using this flat plate, 60 degree gloss was measured according to JIS-K7150 using a gloss meter (manufactured by HORIBA; IG320).

[Surface appearance change rate (depending on molding conditions)]
The gloss of the flat plate with a filling time of 0.5 seconds and 1.5 seconds produced during the surface gloss measurement was substituted into the following formula to calculate the surface appearance change rate. It was judged that the smaller the numerical value, the less the influence on the appearance caused by changing the molding conditions.
Surface appearance change rate (%) = [{(surface gloss of molded product with filling time of 0.5 seconds) − (surface gloss of molded product with filling time of 1.5 seconds)} / (molding with filling time of 0.5 seconds) Product surface gloss)] × 100

[Chip generation (workability)]
The amount of chips dropped by sieving 1 kg of the polyamide resin pellets obtained in Examples and Comparative Examples described later using a 40 mesh sieve (aperture: 0.425 mm) for 1 minute was measured by the following method. Asked.
Chip generation amount (% by mass) = {Amount of chip (kg) / Polyamide resin pellet 1 kg} × 100 The smaller the amount of the chip, the better the workability.

[Molding cycle]
(Measuring method)
Molding was performed under the following molding conditions, and the limit total molding cycle time at which there was no mold release defect when 50 shots were continuously molded while shortening only the cooling time was determined. The smaller the number, the shorter the molding cycle and the better.
(Molding condition)
Injection molding machine: PS40E manufactured by Nissei Plastic Industry Co., Ltd.
Molded product to be obtained: 60 × 60 × 3 mm flat plate cylinder temperature: 300 ° C.
Mold temperature: 80 ℃
Plasticization stroke: 12mm
Screw rotation speed: 250rpm
Back pressure: 10%
Injection speed: 40%
Injection pressure: 30%
Molding cycle time: Injection starts 2 seconds, pause 0.3 seconds, cooling time 13 seconds

[Tensile fracture strength]
Made by Toshiba Machine Co., Ltd .; using an IS-50EP injection molding machine, the resin temperature was set to 290 ° C., the mold temperature was set to 100 ° C., and the molding conditions were injection + holding time: 25 seconds, cooling time: 15 seconds. An ISO type A multi-purpose test piece was molded. Using the obtained multipurpose test piece, the tensile strength at break was measured according to ISO 527 under the condition of a tensile speed of 5 mm / min. The obtained breaking strength was defined as the tensile breaking strength.

(2) The raw materials used in Examples and Comparative Examples are shown below.
(A) Polyamide resin: Polyamide (A-1) obtained in Production Example 1 below
Production Example 1: Polyamide 66 (A-1)
1500 g of equimolar salt of adipic acid and hexamethylenediamine and 0.5 mol% excess of adipic acid with respect to all equimolar salt components were dissolved in 1500 g of distilled water to obtain a 50% by mass aqueous solution of raw material monomers. The obtained aqueous solution was charged into an autoclave having an internal volume of 5.4 L, and the inside of the autoclave was replaced with nitrogen. While stirring this aqueous solution at a temperature of 110 to 150 ° C., water vapor was gradually removed to a solution concentration of 70% by mass and the solution was concentrated. Thereafter, the internal temperature was raised to 220 ° C. At this time, the autoclave was pressurized to 1.8 MPa. The reaction was continued for 1 hour while gradually removing water vapor and maintaining the pressure at 1.8 MPa until the internal temperature reached 270 ° C.

  Thereafter, the pressure is reduced to atmospheric pressure over about 1 hour, and after reaching atmospheric pressure, the pellets are discharged in a strand form from the lower nozzle, water-cooled and cut to obtain polyamide (A-1) pellets. It was. The obtained pellets were dried in a nitrogen stream at 90 ° C. for 4 hours. The polyamide (A-1) had a 98% sulfuric acid relative viscosity [ηr: 25 ° C., 1 g / 100 ml] of 2.71 and a C / N ratio = 6.

(B) Glass fiber B-1: Element content rate Si: 25.8, Al: 9.0, Ca: 7.7, Mg: 6.0, Na: 1.0 Total: 49.5 mass%
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand B-2: element content Si: 27.7, Al: 9.0, Ca: 6.5, Mg: 7.6, Na: 1.0 Total: 51.8% by mass
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand B-3: element content Si: 25.8, Al: 8.0, Ca: 10.4, Mg: 8.5, Na: 1.0 Total: 53.7% by mass
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand B-4: element content Si: 27.1, Al: 12.5, Ca: 9.1, Mg: 6.0, Na: 1.0 Total: 55.7% by mass
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand

B-5: Element content rate Si: 28.1, Al: 10.6, Ca: 6.8, Mg: 6.1, Na: 0.1 Total: 51.7% by mass
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand This glass fiber is a glass fiber used in Example 1 of the prior art document JP-A-2015-105359.
B-6: Element content rate Si: 29.1, Al: 9.1, Ca: 8.3, Mg: 4.8, Na: 0.5 Total: 51.8 mass% Fe: 0.1 mass%
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand This glass fiber is a glass fiber described in Example 7 of JP 2009-514773 A.
B-7: Element content rate Si: 25.5, Al: 7.6, Ca: 15.9, Mg: 0.5, Na: 0.3 Total: 49.8 mass% B: 2.0 mass% , Zr: 0.2 mass%, Fe: 0.1 mass%, K: 0.2 mass%
Surface treatment agent: silane coupling agent, cut length: 3 mm glass fiber chopped strand This glass fiber is a glass fiber used in Comparative Example 1 of Japanese Patent Application Laid-Open No. 2015-105359.

Table 1 shows the element contents of the glass fibers B-1 to B-7.

(C) Lubricant C-1: Aluminum stearate C-2: Calcium montanate

Example 1
The polyamide resin (A-1) and the lubricant (C-1) of Production Example 1 described above were manufactured by Coperion, ZSK 40 mm twin screw extruder (set temperature: polyamide resin (A-1) obtained according to the above melting point measurement method) The temperature was about 30 ° C. higher than the melting point, and the screw rotation speed was 300 rpm. Furthermore, the glass fiber (B-1) was supplied by the mass part shown in following Table 2 from the side feed port. The melt-kneaded product extruded from the die outlet was cooled in a strand shape and pelletized to obtain polyamide resin pellets.
By the above method, the above-described surface gloss and surface appearance change rate, chip generation amount, molding cycle, and tensile fracture strength were measured.
The evaluation results are shown in Table 2 below.

(Examples 2-6, Comparative Examples 1-5)
Pellets were obtained in the same manner as in Example 1 except that the glass fibers and the lubricant were blended in the proportions shown in Table 2.
Table 2 shows the compositions and evaluation results of the examples and comparative examples.

As shown in Table 2, in Examples 1-6, the gloss at a filling time of 1.5 seconds, the surface appearance change rate, and the amount of chips generated were Comparative Examples 3, 4 using B-7 which is E glass. It can be seen that this is an improvement over Comparative Examples 1 and 2 using B-5 and B-6 called S glass described in the prior art document.
It is known that the gloss and tensile strength are improved by using S glass compared with the case of using E glass, but when glass fiber in the range of the present invention is used, a comparative example using S glass. In addition to showing gloss and tensile fracture strength at a filling time of 0.5 seconds equivalent to 1 and 2, the appearance improvement when the filling time was not seen in Comparative Examples 1 and 2 and the reduction in the amount of chips generated An unexpected effect was obtained.

  The polyamide resin composition of the present invention has excellent mechanical properties and excellent molding condition dependency with little change in surface appearance even when the molding conditions are changed. Molded products using the same are used in the automotive field. There is industrial applicability in the electrical / electronic field, machine industry field, office equipment field, aerospace field, etc.

Claims (7)

  (A) The polyamide fiber is 5 to 200 parts by mass with respect to 100 parts by mass of the polyamide resin, and the Si element content in 100% by mass of the (B) glass fiber is 25 to 28.2% by mass. And the polyamide resin composition whose Na element content rate is 0.4-2 mass%.   The (B) glass fiber further contains Al, Mg and Ca, the Si / Mg mass ratio in 100% by mass of the (B) glass fiber is 3 to 5.5, and the Al / Ca mass ratio is The polyamide resin composition according to claim 1, which is 0.5 to 1.5.   In (B) 100% by mass of the glass fiber, the Al element content is 6 to 12% by mass, the Ca element content is 7 to 11% by mass, the Mg element content is 3 to 8% by mass, Si, Al, The polyamide resin composition according to claim 1 or 2, wherein the total content of Ca, Mg and Na elements is 48 to 52 mass%.   The polyamide resin composition according to any one of claims 1 to 3, wherein the (B) glass fiber is 50 to 200 parts by mass with respect to 100 parts by mass of the (A) polyamide resin.   (E) The polyamide resin composition according to any one of claims 1 to 4, which contains at least one selected from a higher fatty acid metal salt, a higher fatty acid ester wax, and a higher fatty acid amide as a lubricant.   The polyamide resin composition according to any one of claims 1 to 5, wherein the (B) glass fiber is subjected to a coupling treatment with a silane coupling agent.   The molded object formed by shape | molding the polyamide resin composition of any one of Claims 1-6.