JP2010248403A - Polyamide resin composition and molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition and a molding excellent in shock resistance as well as rigidity and dimensional stability when absorbing water, and excellent in molding property. <P>SOLUTION: The polyamide resin composition contains (A) a copolyamide resin comprising 70 to 85 mass% of a hexamethylene adipamide unit (N66) and 15 to 30 mass% of a hexamethylene isophthalamide unit (N6I) and a caproamide unit (N6) in a compounding mass ratio (N6I/M6) of 1.0 or more; (B) an aliphatic polyamide resin obtained from an aminocarboxylic acid and/or a combination of diamine and a dicarboxylic acid, in which a ratio (C/N) of the number of carbon atoms to nitrogen atoms ranges from 7 to 12 and relative viscosity in accordance with JIS K6810 ranges from 2.0 to 2.5; and (C) a glass fiber. The weight ratio (A/B) ranges from 40/60 to 60/40; and the component (C) is included by 20 to 250 parts by mass with respect to total 100 parts by mass of the component (A) and component (B). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyamide resin composition and a molded body comprising the same.

  Portable electronic devices typified by mobile phones and digital cameras often drop because they are carried around, and in particular, exterior parts such as housings and internal reinforcements are required to have sufficient strength. It is done. The materials that have been used for these parts have been magnesium alloys and aluminum die casts, but they have been replaced by resin materials because they are required to reduce the weight of equipment, have insulation properties for parts, and are difficult to process. ing.

Among them, a polyamide resin composition in which an inorganic filler is blended at a high concentration has been devised and used for parts that have become thinner with the recent miniaturization of portable electronic devices. For example, Patent Document 1 discloses a polyamide resin composition composed of a terpolymer polyamide resin and an inorganic filler.
Patent Document 2 discloses a polyamide resin composition comprising a terpolymer polyamide resin, polyamide 6 or polyamide 610, and an inorganic filler.
Patent Document 3 discloses a polyamide resin composition comprising a specific semi-aromatic polyamide resin, a fibrous filler and a plate-like filler.

JP 2000-219808 A JP 2006-193727 A JP 2008-007753 A

  However, the techniques described in Patent Documents 1 and 2 have a problem that burrs are likely to occur when molding a thin molded product. The technique described in Patent Document 3 has a problem that it is inferior in impact resistance and cannot obtain sufficient strength, although the generation of burrs during molding can be suppressed.

  Moreover, when a polyamide resin is formed into a molded body, there is a problem that rigidity and dimensional stability at the time of water absorption are lowered. Development of a technology that can solve this problem is also desired.

  The present invention has been made in view of the above circumstances, and provides a polyamide resin composition having excellent impact resistance, excellent rigidity and dimensional stability at the time of water absorption, and excellent moldability, and a molded body thereof. For the purpose.

  As a result of intensive studies to solve the above problems, the present inventor includes a polyamide resin having a specific composition ratio, a specific long-chain polyamide resin, and a high-concentration fiber length inorganic filler. The present inventors have found that a polyamide resin composition having excellent impact resistance, excellent rigidity and dimensional stability during water absorption, and excellent moldability can be obtained, and the present invention has been completed.

That is, the present invention
(1) (A) 70 to 85% by mass of hexamethylene adipamide units (N66) obtained from hexamethylenediamine and adipic acid, hexamethyleneisophthalamide units (N6I) and caproamide obtained from hexamethylenediamine and isophthalic acid A ternary copolymer comprising 15 to 30% by mass of repeating structural units of the unit (N6), and a blending mass ratio (N61 / N6) of the hexamethylene isophthalamide unit to the caproamide unit is 1.0 or more. A copolymerized polyamide resin,
(B) The ratio (C / N) of the number of carbon atoms to the number of nitrogen atoms contained is 7 or more and 12 or less, obtained from a combination of aminocarboxylic acid and / or diamine and dicarboxylic acid, and according to JIS K 6810 An aliphatic polyamide resin having a relative viscosity (ηr) measured at 25 ° C. of 2.0 to 2.5, and a 98% sulfuric acid concentration of 1%,
(C) glass fiber,
The mass ratio (A / B) of the component (A) and the component (B) is 40/60 to 60/40,
A polyamide resin composition comprising 20 to 250 parts by mass of the component (C) with respect to a total of 100 parts by mass of the component (A) and the component (B),
(2) The polyamide resin composition of (1), wherein the component (B) is polyamide 612,
(3) (D) The polyamide resin composition according to (1) or (2), further comprising a quaternary copolymer comprising the structural unit of component (A) and the structural unit of component (B). ,
(4) The polyamide resin composition of (3), wherein the component (B) is polyamide 612, and the component (D) is a quaternary copolymer composed of N66, N61, N6 and polyamide 612 units.
(5) The polyamide resin composition according to any one of (1) to (4), further comprising zinc sulfide,
(6) A molded body comprising the polyamide resin composition according to any one of (1) to (5),
It is.

  The polyamide resin composition of the present invention has excellent impact resistance when formed into a molded body, and has an effect of excellent balance between moldability, rigidity at the time of water absorption and dimensional stability.

FIG. 3 is a simplified diagram of a molded product used for burr measurement in an example.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist thereof.

  The polyamide resin composition of this embodiment comprises (A) 70 to 85% by mass of hexamethylene adipamide units (N66) obtained from hexamethylene diamine and adipic acid, and hexamethylene isophthalic acid obtained from hexamethylene diamine and isophthalic acid. It is a ternary copolymer composed of 15 to 30% by mass of repeating structural units of an amide unit (N6I) and a caproamide unit (N6), and a blending mass ratio of the hexamethyleneisophthalamide unit and the caproamide unit (N61 / N6) Is a copolymerized polyamide resin having a ratio of 1.0 or more and (B) the ratio of the number of carbon atoms to the number of nitrogen atoms (C / N) is 7 or more and 12 or less, and an aminocarboxylic acid and / or diamine and dicarboxylic acid Obtained from a combination of acids and 98% sulfuric acid concentration 1% according to JIS K 6810, An aliphatic polyamide resin having a relative viscosity (ηr) measured at 5 ° C. of 2.0 to 2.5, and (C) a glass fiber, the component (A) and the component (B) The mass ratio (A / B) is 40/60 to 60/40, and 20 to 250 parts by mass of the component (C) are added to 100 parts by mass of the total of the component (A) and the component (B). Is included. By containing the component (A), the component (B), and the component (C) in the above proportions, a molded body having excellent impact resistance and excellent balance between moldability, rigidity at the time of water absorption and dimensional stability is obtained. be able to.

  The (A) copolymerized polyamide resin of this embodiment is a hexamethylene adipamide unit (hereinafter referred to as “N66”) obtained from adipic acid and hexamethylenediamine, and hexamethylene obtained from isophthalic acid and hexamethylenediamine. It consists of an isophthalamide unit (hereinafter referred to as “N6I”) and a capramide unit composed of caprolactam (hereinafter referred to as “N6”). As for the composition ratio of each component, N66 is 70 to 85 mass%, and the total of N6I and N6 is 15 to 30 mass%. The blending ratio of N6I units to N6 units (N6I / N6) is 1 or more. From the viewpoint of the crystallinity of the copolymerized polyamide resin and the rigidity at the time of water absorption, N66 is preferably 72 to 83 mass%, the total of N6I and N6 is 17 to 28 mass%, and the blending ratio of N6I and N6 is 3 That's it

  (A) The degree of polymerization of the copolymerized polyamide resin is a relative viscosity ηr measured at a concentration of 1% in 98% sulfuric acid according to JIS K 6810 at 25 ° C., preferably 1.5 to 2.8, more preferably It is 1.6 to 2.7, more preferably 1.7 to 2.6. By using a copolymerized polyamide in such a range, the gloss of the surface of the resin molded product can be further improved.

  In the (B) aliphatic polyamide resin of the present embodiment, the ratio of carbon atoms to the number of nitrogen atoms contained (C / N) is 7 or more and 12 or less, and a combination of aminocarboxylic acid and / or diamine and dicarboxylic acid. It is an aliphatic polyamide resin obtained and having a relative viscosity (ηr) of 2.0 to 2.5 measured at 25 ° C. with a concentration of 1% in 98% sulfuric acid according to JIS K 6810.

  Component (B) is a polymer having an amide bond (—NHCO—) in the main chain, the ratio of the number of carbon atoms to the number of nitrogen atoms (C / N) of 7 or more and 12 or less. Further, it is composed of an aliphatic monomer. For example, polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecalactam (polyamide 11), polydodecalactam (polyamide). 12) and polyamide copolymers containing at least two different polyamide-forming components among them, and mixtures thereof. Among these, preferred (B) aliphatic polyamide resins include polyamide 612 and polyamide 12 from the viewpoint of rigidity during water absorption. More preferred is polyamide 612.

  The degree of polymerization of the aliphatic polyamide as the component (B) in this embodiment is 2.0 to 2.5 in terms of a relative viscosity ηr measured at 25 ° C. in a 98% sulfuric acid concentration of 1% according to JIS K6810. Preferably, it is 2.1-2.4. By using an aliphatic polyamide in such a range, the gloss of the surface of the resin molded product can be improved.

  (C) The glass fiber of this embodiment can use what is normally used for a thermoplastic resin, There is no restriction | limiting in particular in a fiber diameter and length, For example, an average fiber diameter is 5-30 micrometers chopped strand. , Roving or milled fiber. When using chopped strands, the length may be appropriately selected within the range of 0.1 to 6 mm.

  For these glass fibers, it is also possible to preferably use a glass fiber with a generally known sizing agent or silane coupling agent attached to its surface. For example, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, etc. Available.

  In this embodiment, it is preferable that the component (D) further includes a quaternary copolymer component composed of the structural unit of the component (A) and the structural unit of the component (B). The (D) component quaternary copolymer component has the same component as the component used as the component (A) and the same component as the component used as the component (B). For example, when a polyamide resin composed of N66, N6, and N6I is used as the component (A) and a polyamide 612 is used as the component (B), a quaternary copolymer containing polyamide 612 units in addition to N66, N6, and N6I (D ) As a component. By adding the component (D), it is possible to further increase the mixed state of the component (A) and the component (B), thereby contributing to improvement in impact strength and fluidity. In particular, by making the aliphatic polyamide used in the quaternary copolymer of the component (D) the same as the component (B), it is possible to further increase the mixed state of the component (A) and the component (B). (However, the action is not limited to this.) In this embodiment, it is particularly preferable that the component (B) is polyamide 612 and the component (D) is a quaternary copolymer composed of N66 units, N6I units, N6I and polyamide 612 units. By setting it as such a polyamide resin composition, the mixed state of (A) component and (B) component can be improved further.

  The content of the quaternary copolymer component of the component (A) and the component (B) in the component (D) is not particularly limited, but from the viewpoint of rigidity and crystallinity during water absorption, the mass ratio (A / B) Is preferably 30/70 to 70/30.

  When obtaining the polyamide resin composition of this embodiment, the mass ratio (A / B) of (A) copolymer polyamide resin and (B) aliphatic polyamide resin is 40 / 60-60 / 40, From the viewpoint of rigidity, the mass ratio (A / B) is preferably 45/55 to 60/40.

  The blending amount of the (C) glass fiber in the polyamide resin composition of the present embodiment is (C) a glass fiber 20 to a total of 100 parts by mass of the (A) copolymer polyamide resin and the (B) aliphatic polyamide resin. From the viewpoint of the balance between rigidity and fluidity, it is preferably 250 parts by mass, and preferably 60 to 180 parts by mass of (C) component, more preferably (C) with respect to 100 parts by mass of component (A) and component (B). It is 80-150 mass parts.

  The blending amount of the (D) quaternary copolymer in the polyamide resin composition of the present embodiment is 100 parts by mass in total of (A) the copolymerized polyamide resin and (B) the aliphatic polyamide resin from the viewpoint of heat resistance and rigidity. The (D) quaternary copolymer is preferably 2 to 20 parts by mass, more preferably 3 to 10 parts by mass.

  The polyamide resin composition of the present embodiment includes other polyamide resins and other polymers, fillers, crystal nucleating agents, heat stabilizers, ultraviolet absorbers and the like as long as the purpose of the present embodiment is not impaired as necessary. Stabilizers, flame retardants, antistatic agents, plasticizers, lubricants, colorants, coupling agents and the like can be added.

  Examples of other polyamide resins include polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide 9T, polyamide 12T, polyamide MXD6, and polyamide copolymers containing at least two different polyamide-forming components. .

  Other polymers include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-octene copolymer, styrene-ethylene copolymer, styrene-isoprene copolymer, styrene-ethylenebutylene-styrene block copolymer. Styrene-ethylenepropylene-styrene block copolymer, liquid crystal resin, unsaturated aliphatic carboxylic acid anhydride-modified polyphenylene ether resin, polyphenylene sulfide and the like.

  As fillers, inorganic fibers such as glass fiber and carbon fiber, mica, talc, clay mineral, alumina, silica, apatite, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc stannate, zinc hydroxystannate, cellulose Etc.

  Examples of the crystal nucleating agent include kaolin, boron nitride, and phosphoric acid-2,2'-methylenebis (4,6-di-t-butylphenyl) sodium.

  Examples of the stabilizer include metal phosphites such as sodium hypophosphite, hindered phenols, organic phosphorus compounds and hindered amines.

  Examples of the antistatic agent include sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester and higher alcohol fatty acid ester.

  Examples of the flame retardant include ammonium polyphosphate, melamine cyanurate, succinoguanamine, melamine polyphosphate, melamine sulfate, melamine phthalate, and aluminum phosphate.

  Examples of lubricants and plasticizers include higher fatty acid metal salts, higher fatty acid amides, and higher fatty acid esters.

  Examples of the colorant include zinc sulfide, titanium white, carbon black, azine dyes, and phthalocyanine derivatives. Among these, zinc sulfide is preferable from the viewpoint of rigidity and impact resistance. The blending amount of zinc sulfide in the polyamide resin composition of the present embodiment is preferably 0.1 to 5 parts by mass in 100 parts by mass of the polyamide resin composition of the present embodiment from the viewpoint of heat resistance and rigidity. More preferably, it is 0.5-3 mass parts.

  As a method for obtaining the polyamide resin composition of the present embodiment, it can be produced by melt kneading. As a device for performing melt kneading, a kneading machine generally used can be applied. For example, a single-screw or multi-screw kneading extruder, a Banbury mixer, a roll, or the like may be used. There is no particular restriction on the order of melt-kneading, and a method of kneading all the components simultaneously, or a method of kneading any two components in advance and kneading the obtained one with the remaining one component, further in the middle of the extruder Alternatively, a method may be used in which each component is sequentially fed and kneaded. The kneading temperature is preferably 1 to 100 degrees higher than the highest melting point or softening point of the copolymerized polyamide resin and aliphatic polyamide resin, more preferably 10 to 60 ° C, and still more preferably 20 to 50 ° C. That is, it is preferable that the resin used as a raw material in the present embodiment is melted and mixed during the production method. The melting point or softening point can be determined by differential scanning calorimetry (DSC) measurement according to JIS K7121. When the temperature is out of the temperature range, the effects of the present embodiment tend to be hardly exhibited, and at the same time, the productivity tends to be lowered.

  The molded body obtained from the polyamide resin composition of the present embodiment is excellent in impact resistance, and has excellent balance of rigidity and dimensional stability upon water absorption and moldability. Can be suitably used.

  Hereinafter, the present embodiment will be described in more detail with reference to examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist. In addition, the physical property evaluation described in the following examples and comparative examples was performed as follows.

(1) Flexural modulus (dry state)
Using an injection molding machine (PS-40E manufactured by Nissei Resin Co., Ltd.), the cylinder temperature was set to 280 ° C. and the mold temperature was set to 100 ° C. After obtaining a test piece for evaluation with a thickness of 4 mm, bending according to ISO 178 The elastic modulus was measured.

(2) Flexural modulus (wet condition)
The test piece obtained by injection molding in the same manner as in (1) was left in an environment of 23 ° C. × 50% relative humidity, and left to stand until the mass became constant, and a water absorption treatment was performed. The test piece after the water absorption treatment was subjected to a bending test in the same manner as (1).

(3) Change in water absorption dimension, water absorption rate Using an injection molding machine (FN3000 manufactured by Nissei Resin Co., Ltd.), a cylinder temperature of 280 ° C. and a mold temperature of 100 ° C. are set, and a flat plate of thickness 3 mm × width 60 mm × length 90 mm After getting
The length dimension (L1) was measured. The measurement position at this time was the center of the width and the center of the end. Using this test piece, it was left in an environment of 23 ° C. × 50% relative humidity, left to stand until the mass became constant, and subjected to water absorption treatment, and then the dimension (L2) was measured in the same manner. The water absorption dimensional change (ΔL) was calculated as follows.
ΔL = (L2−L1) / L1 × 100
The water absorption (W3) was calculated as follows by measuring the test piece weight (W1) immediately after molding of the same flat plate test piece and the test piece weight (W2) after water absorption treatment.
W3 = (W2-W1) / W1 × 100

(4) Impact resistance The test piece obtained in (1) was cut, and a Charpy impact test was carried out by a method based on ISO 179 with a notched test piece to determine the impact resistance.

(5) Fluidity (Burr)
Using an injection molding machine (FE120 manufactured by Nissei Resin Co., Ltd.), the cylinder temperature was set to 280 ° C. and the mold temperature was set to 100 ° C., and the molded product shown in FIG. 1 was injection molded. When molding was performed at a pressure filled with the injection molded product, the length of the burr that appeared at the gas vent portion (thickness: 100 μm) provided for burr evaluation was measured.
Next, the raw materials used in the examples of this embodiment will be described. The polyamide copolymer as component (A), the polyamide polymer as component (B), and the 43-component copolymer as component (D) were prepared based on the production examples described below. Moreover, the raw material used for the manufacture example, (C) component, and (E) other raw materials used the commercially available thing.

[raw materials]
Hexamethylenediamine (made by Wako Pure Chemical Industries, trade name: hexamethylenediamine)
Adipic acid (made by Wako Pure Chemical Industries, trade name: adipic acid)
Isophthalic acid (made by Wako Pure Chemical Industries, trade name: isophthalic acid)
Dodecanedioic acid (made by Wako Pure Chemical Industries, trade name: dodecanedioic acid)
Caprolactam (made by Wako Pure Chemical Industries, trade name: Caprolactam)
(C) Glass fiber manufactured by Nippon Electric Glass Co., Ltd., trade name ECS03T-275 / H
(E) Other raw materials Zinc sulfide: manufactured by Sachtleben Chemie GmbH, trade name: SachtolithHD

(Production Example 1)
An aqueous solution 2 containing 12 kg of an equimolar salt of hexamethylenediamine and adipic acid as a polymerization component in an amount equivalent to 50% by mass as a polyamide resin and an aqueous solution 2 containing 50% by mass in an equimolar salt of hexamethylenediamine and isophthalic acid as a polyamide resin. 0.75 kg of an aqueous solution containing .25 kg and ε-caprolactam corresponding to 50% by mass as a polyamide resin was prepared. Next, the aqueous solution was charged into a 40 liter autoclave having a stirring device and having a discharge nozzle at the bottom, and the aqueous solution was sufficiently stirred at a temperature of 50 ° C. Next, after the inside of the autoclave was sufficiently substituted with nitrogen, the temperature inside the autoclave was increased from 50 ° C. to about 270 ° C. while stirring the aqueous solution. At this time, the pressure in the autoclave was about 1.8 MPa in terms of gauge pressure, but water was discharged from the system as needed so that the pressure did not exceed 1.8 MPa. Further, the polymerization time was adjusted so that the relative viscosity of the polyamide resin became the target relative viscosity. After the polymerization in the autoclave is completed, the polyamide resin is sent out in a strand form from the lower nozzle, and after water cooling and cutting, a pellet-like polyhexamethylene adipamide, polyhexamethylene isophthalamide copolymer and polycoupleramide (polyamide 66). / 6I / 6). This polyamide copolymer was vacuum dried at 80 ° C. for 24 hours. When the relative viscosity (ηr) of the polyamide copolymer was measured as described above, it was 2.10.

(Production Example 2)
15 kg of an aqueous solution containing an equimolar salt of hexamethylenediamine and dodecanedioic acid as a polymerization component in an amount corresponding to 50% by mass as a polyamide resin was prepared. Next, the aqueous solution was charged into a 40 liter autoclave having a stirring device and having a discharge nozzle at the bottom, and the aqueous solution was sufficiently stirred at a temperature of 50 ° C. Next, after the inside of the autoclave was sufficiently substituted with nitrogen, the temperature inside the autoclave was increased from 50 ° C. to about 270 ° C. while stirring the aqueous solution. At this time, the pressure in the autoclave was about 1.8 MPa in terms of gauge pressure, but water was discharged from the system as needed so that the pressure did not exceed 1.8 MPa. The polymerization time was adjusted so that the relative viscosity of the polyamide polymer was the target relative viscosity. After the polymerization in the autoclave was completed, the polyamide polymer was sent out in a strand form from the lower nozzle, and after water cooling and cutting, pelletized polyhexamethylene dodecamide (polyamide 612) was obtained. This polyamide 612 was vacuum dried at 80 ° C. for 24 hours. It was 2.10 when the relative viscosity ((eta) r) of the polyamide 612 was measured as mentioned above.

(Production Example 3)
15 kg of an aqueous solution containing an equimolar salt of hexamethylenediamine and adipic acid as a polymerization component in an amount corresponding to 50% by mass as a polyamide resin was prepared. Next, the aqueous solution was charged into a 40 liter autoclave having a stirring device and having a discharge nozzle at the bottom, and the aqueous solution was sufficiently stirred at a temperature of 50 ° C. Next, after the inside of the autoclave was sufficiently substituted with nitrogen, the temperature inside the autoclave was increased from 50 ° C. to about 270 ° C. while stirring the aqueous solution. At this time, the pressure in the autoclave was about 1.8 MPa in terms of gauge pressure, but water was discharged from the system as needed so that the pressure did not exceed 1.8 MPa. The polymerization time was adjusted so that the relative viscosity of the polyamide polymer was the target relative viscosity. After the polymerization in the autoclave was completed, the polyamide polymer was sent out in a strand form from the lower nozzle, and water-cooling and cutting were performed to obtain pellet-shaped polyhexamethylene adipamide (polyamide 66). This polyamide 66 was vacuum dried at 80 ° C. for 24 hours. When the relative viscosity (ηr) of the polyamide 66 was measured as described above, it was 2.60.

(Production Example 4)
An aqueous solution containing 6 kg of an equimolar salt of hexamethylenediamine and adipic acid as a polymerization component in an amount equivalent to 50% by mass as a polyamide resin and an aqueous solution containing 50% by mass in an equimolar salt of hexamethylenediamine and isophthalic acid as a polyamide resin. 1.12 kg and 0.38 kg of an aqueous solution containing 50% by mass of ε-caprolactam as a polyamide resin, and 7.5 kg of an aqueous solution containing 50% by mass of an equimolar salt of hexamethylenediamine and dodecanedioic acid as a polyamide resin were prepared. did. Next, the aqueous solution was charged into a 40 liter autoclave having a stirring device and having a discharge nozzle at the bottom, and the aqueous solution was sufficiently stirred at a temperature of 50 ° C. Next, after the inside of the autoclave was sufficiently substituted with nitrogen, the temperature inside the autoclave was increased from 50 ° C. to about 270 ° C. while stirring the aqueous solution. At this time, the pressure in the autoclave was about 1.8 MPa in terms of gauge pressure, but water was discharged from the system as needed so that the pressure did not exceed 1.8 MPa. Further, the polymerization time was adjusted so that the relative viscosity of the polyamide resin became the target relative viscosity. After the polymerization in the autoclave is completed, the polyamide resin is sent in a strand form from the lower nozzle, and after water cooling and cutting, pelletized polyhexamethylene adipamide, polyhexamethylene isophthalamide, polycoupleramide and polyhexamethylene sebacamide The copolymer (polyamide 66 / 6I / 6/612) was obtained. This polyamide copolymer was vacuum dried at 80 ° C. for 24 hours. The relative viscosity (ηr) of the polyamide copolymer was measured as described above and found to be 2.05.

[Example 1]
A mixture of 50 parts by mass of polyamide 66 / 6I / 6 copolymer of Production Example 1 and 50 parts by mass of polyamide 612 polymer of Production Example 2 was mixed with a twin screw extruder (TEM 35 manufactured by Toshiba Machine Co., Ltd. Using a directional screw rotation type, L / D = 47.6 (D = 37 mmφ), when the polyamide mixture is sufficiently melted, side feed is performed so that the glass fiber becomes 100 parts by mass with respect to 100 parts by mass of the polyamide mixture. Melting and kneading were performed. Extrusion was performed while reducing the pressure at a screw speed of 300 rpm, a cylinder temperature of 280 ° C. (the polymer temperature in the vicinity of the tip nozzle was 290 ° C.), and a rate of 50 kg / hr. The polymer was discharged in a strand form from the tip nozzle, water-cooled and cut to form pellets. Table 1 shows the evaluation results of the moldings obtained.

[Example 2]
A mixture of 50 parts by mass of polyamide 66 / 6I / 6 copolymer of Production Example 1 and 50 parts by mass of polyamide 612 polymer of Production Example 2 was mixed with a twin screw extruder (TEM 35 manufactured by Toshiba Machine Co., Ltd. Using a directional screw rotation type, L / D = 47.6 (D = 37 mmφ), when the polyamide mixture is sufficiently melted, side feed is performed so that the glass fiber becomes 150 parts by mass with respect to 100 parts by mass of the polyamide mixture. Melting and kneading were performed. Extrusion was performed while reducing the pressure at a screw speed of 300 rpm, a cylinder temperature of 280 ° C. (the polymer temperature in the vicinity of the tip nozzle was 290 ° C.), and a rate of 50 kg / hr. The polymer was discharged in a strand form from the tip nozzle, water-cooled and cut to form pellets. Table 1 shows the evaluation results of the moldings obtained.

[Comparative Example 1]
100 parts by mass of polyamide 66 / 6I / 6 copolymer of Production Example 1 was added to a twin-screw extruder (TEM35, manufactured by Toshiba Machine Co., Ltd., twin-screw rotation type, L / D = 47.6 (D = 37 mmφ)) ) Was used to carry out melt-kneading by side-feeding from a place where the polyamide mixture was sufficiently melted to 100 parts by mass of the polyamide copolymer to 150 parts by mass of glass fibers. Extrusion was performed while reducing the pressure at a screw speed of 300 rpm, a cylinder temperature of 280 ° C. (the polymer temperature in the vicinity of the tip nozzle was 290 ° C.), and a rate of 50 kg / hr. The polymer was discharged in a strand form from the tip nozzle, water-cooled and cut to form pellets. Table 1 shows the evaluation results of the moldings obtained.

[Comparative Example 2]
A mixture of 50 parts by mass of polyamide 66 / 6I / 6 copolymer of Production Example 1 and 50 parts by mass of polyamide 66 polymer of Production Example 3 was mixed with a twin-screw extruder (TEM35, manufactured by Toshiba Machine Co., Ltd., biaxially in the same direction). Using a screw rotation type, L / D = 47.6 (D = 37 mmφ)), when the polyamide mixture is sufficiently melted, side feed is performed so that the glass fiber becomes 150 parts by mass with respect to 100 parts by mass of the polyamide mixture. Melt kneading was performed. Extrusion was performed while reducing the pressure at a screw speed of 300 rpm, a cylinder temperature of 280 ° C. (the polymer temperature in the vicinity of the tip nozzle was 290 ° C.), and a rate of 50 kg / hr. The polymer was discharged in a strand form from the tip nozzle, water-cooled and cut to form pellets. Table 1 shows the evaluation results of the moldings obtained.

[Example 3]
From 45 parts by mass of polyamide 66 / 6I / 6 copolymer of Production Example 1, 45 parts by mass of polyamide 612 polymer of Production Example 2, and 10 parts by mass of polyamide 66 / 6I / 6/612 copolymer of Production Example 4 From the place where the polyamide mixture was sufficiently melted using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd., twin screw co-rotating screw type, L / D = 47.6 (D = 37 mmφ)) It melt-kneaded by carrying out the side feed so that it might become 150 mass parts of glass fibers with respect to 100 mass parts of polyamide mixtures. Extrusion was performed while reducing the pressure at a screw speed of 300 rpm, a cylinder temperature of 280 ° C. (the polymer temperature in the vicinity of the tip nozzle was 290 ° C.), and a rate of 50 kg / hr. The polymer was discharged in a strand form from the tip nozzle, water-cooled and cut to form pellets. Table 1 shows the evaluation results of the moldings obtained.

[Example 4]
A mixture comprising 48.8 parts by mass of polyamide 66 / 6I / 6 copolymer of Production Example 1, 48.8 parts by mass of polyamide 612 polymer of Production Example 2, and 2.4 parts by mass of zinc sulfide was biaxially extruded. When the polyamide mixture is sufficiently melted using a machine (TEM35, manufactured by Toshiba Machine Co., Ltd., TEM35, 2-axis concentric screw rotation type, L / D = 47.6 (D = 37 mmφ)), a mixture of polyamide and zinc sulfide 100 is obtained. Side feed was performed so that the glass fiber was 150 parts by mass with respect to the mass part, and melt kneading was performed. Extrusion was performed while reducing the pressure at a screw speed of 300 rpm, a cylinder temperature of 280 ° C. (the polymer temperature in the vicinity of the tip nozzle was 290 ° C.), and a rate of 50 kg / hr. The polymer was discharged in a strand form from the tip nozzle, water-cooled and cut to form pellets. Table 1 shows the evaluation results of the moldings obtained.

The molded bodies of Examples 1 to 4 had a small change in flexural modulus in the dry state and the wet state, a small dimensional change rate due to water absorption, a small water absorption rate, and excellent impact resistance. Furthermore, the burr of the molded product was short. That is, the molded bodies of Examples 1 to 4 were excellent in all of rigidity and dimensional stability at the time of water absorption, impact resistance, and moldability. On the other hand, the molded bodies of Comparative Examples 1 and 2 were inferior in any of rigidity and dimensional stability at the time of water absorption, impact resistance, and moldability.
From the above, it was shown that the polyamide resin composition of the present embodiment is excellent in impact resistance when formed into a molded body, is excellent in rigidity and dimensional stability at the time of water absorption, and is excellent in moldability. .

  The polyamide resin composition and molded body of the present invention are excellent in impact resistance, excellent in rigidity and dimensional stability at the time of water absorption, and excellent in moldability, so that various portable electronic devices, electrical and electronic parts, etc. It is useful as an industrial material.

Claims (6)

(A) Hexamethylene adipamide unit (N66) obtained from hexamethylenediamine and adipic acid (N66) 70 to 85% by mass, hexamethyleneisophthalamide unit (N6I) and caproamide unit (N6) obtained from hexamethylenediamine and isophthalic acid ) And 15-30% by mass of repeating structural units, and the blending mass ratio (N61 / N6) of the hexamethyleneisophthalamide units and the caproamide units is 1.0 or more. A copolymerized polyamide resin;
(B) The ratio (C / N) of the number of carbon atoms to the number of nitrogen atoms contained is 7 or more and 12 or less, obtained from a combination of aminocarboxylic acid and / or diamine and dicarboxylic acid, and according to JIS K 6810 An aliphatic polyamide resin having a relative viscosity (ηr) measured at 25 ° C. of 2.0 to 2.5, and a 98% sulfuric acid concentration of 1%,
(C) glass fiber,
The mass ratio (A / B) of the component (A) and the component (B) is 40/60 to 60/40,
A polyamide resin composition comprising 20 to 250 parts by mass of the component (C) with respect to 100 parts by mass in total of the component (A) and the component (B).   The polyamide resin composition according to claim 1, wherein the component (B) is polyamide 612.   The polyamide resin composition according to claim 1 or 2, further comprising a quaternary copolymer comprising (D) the structural unit of the component (A) and the structural unit of the component (B). The component (B) is polyamide 612,
The polyamide resin composition according to claim 3, wherein the component (D) is a quaternary copolymer composed of N66, N61, N6, and polyamide 612 units.   The polyamide resin composition according to any one of claims 1 to 4, further comprising zinc sulfide.   The molded object which consists of a polyamide resin composition as described in any one of Claims 1-5.

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