JP2019178231A - Method for producing polyamide resin composition and method for producing molding - Google Patents

Abstract

To provide a method for producing polyamide resin composition, enabling a molding having high mechanical strength (rigidity) to be imparted.SOLUTION: There is provided the method for producing a polyamide resin composition using an extruder having a main feed opening, a first side feed opening and a second side feed opening in this order, the method comprises the steps of: supplying a polyamide resin (A) from the main feed opening and melting the resin (A); supplying a part of a carbon fiber (B) from a first side feeding opening and melting and mixing a part of the carbon fiber (B); and supplying at least a part of the remainder of the carbon fiber (B) from the second side feed opening and melting and mixing a part of the remainder of the carbon fiber (B). The method satisfies the formula X/Y=45/55-80/20(mass ratio) where X denotes a part of the supply of the carbon fiber (B) and Y denotes at least a part of the supply of the remainder.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a polyamide resin composition and a method for producing a molded body.

  Polyamide resin compositions containing fibrous fillers such as glass fibers are excellent in mechanical properties and thermal properties, and are therefore considered as materials that contribute to weight reduction by substituting metal parts such as automobile parts. The polyamide resin composition containing glass fibers is generally obtained by melt-kneading a polyamide resin and glass fiber chopped strands in an extruder.

  In such a polyamide resin composition, it is possible to improve the strength of the molded body by increasing the filling rate of the glass fiber, but in reality, the strength is lower than that of aluminum and its use is limited.

  As a method for improving the strength of a molded article of a polyamide resin composition, for example, Patent Document 1 includes a polyamide resin, a polyolefin resin, and long fibers having an average fiber length of 2 mm or more, and is manufactured by a pultrusion method. A long fiber reinforced polyamide resin composition is disclosed. Patent Document 2 discloses a carbon fiber reinforced resin composition containing a polyamide resin (A) and a carbon fiber (B) having a tensile strength of 5.1 GPa or more.

JP 2002-234998 A JP 2012-255063 A

  However, since the polyamide resin composition containing long fibers as disclosed in Patent Document 1 is produced by the pultrusion method, special equipment is required, and the production cost tends to be high. Moreover, although the carbon fiber reinforced resin composition of patent document 2 can provide the molded object which has favorable mechanical strength (rigidity), mechanical strength is still not enough.

  This invention is made | formed in view of the said subject, and it aims at providing the manufacturing method of the polyamide resin composition which can provide the molded object which has high mechanical strength (rigidity).

1st of this invention is related with the manufacturing method of the polyamide resin composition which has the following structures.
[1] A method for producing a polyamide resin composition using an extruder having a main feed port, a first side feed port, and a second side feed port in this order from the upstream side in the extrusion direction. A step of supplying and melting the polyamide resin (A) from the feed port, a part of the carbon fiber (B) from the first side feed port, and the molten polyamide resin (A) and the carbon fiber ( A step of melt-kneading a part of B), and further supplying at least a part of the remaining carbon fiber (B) from the second side feed port, and the polyamide resin (A) and the carbon fiber (B) And a step of melt-kneading at least a part of the remaining carbon fiber (B), wherein a supply amount of the carbon fiber (B) is X, and the carbon fiber (B) The manufacturing method of the polyamide resin composition which is X / Y = 45 / 55-80 / 20 (mass ratio) when the supply amount of at least one part of the remainder is set to Y.
[2] The method for producing a polyamide resin composition according to [1], wherein at least a part of the remaining carbon fiber (B) is the entire remaining carbon fiber (B).
[3] When the length of the screw of the extruder is L, an interval between the main feed port and the first side feed port is 0.34L to 0.75L, and the first side feed port The method for producing a polyamide resin composition according to [1] or [2], wherein an interval from the second side feed port is 0.24 L to 0.55 L.
[4] The polyamide resin composition has 40 to 90 parts by mass of the polyamide resin (A) when the total of the polyamide resin (A) and the carbon fiber (B) is 100 parts by mass.
The manufacturing method of the polyamide resin composition in any one of [1]-[3] containing the said carbon fiber (B) 10-60 mass parts.
[5] Production of the polyamide resin composition according to any one of [1] to [4], wherein the polyamide resin (A) has a melting point (Tm) measured by a differential scanning calorimeter of 290 to 340 ° C. Method.
[6] The polyamide resin (A) includes a component unit (a1) derived from dicarboxylic acid and a component unit (a2) derived from diamine, and the component unit (a1) derived from the dicarboxylic acid is Component unit 20-100 mol% derived from terephthalic acid and component unit 0-80 mol derived from aromatic dicarboxylic acid other than terephthalic acid with respect to 100 mol% in total of component units (a1) derived from dicarboxylic acid % And component units derived from aliphatic dicarboxylic acid having 4 to 20 carbon atoms and at least one of 0 to 40 mol% of component units, and component unit (a2) derived from diamine is a component unit derived from diamine ( Based on a component unit derived from a linear aliphatic diamine having 4 to 8 carbon atoms and an alicyclic diamine having 4 to 20 carbon atoms with respect to a total of 100 mol% of a2) The method for producing a polyamide resin composition according to any one of [1] to [5], comprising a total of 50 to 100 mol% of at least one of the coming component units.
[7] The component unit (a2) derived from the diamine is derived from the linear aliphatic diamine having 4 to 8 carbon atoms with respect to 100 mol% in total of the component unit (a2) derived from the diamine. The manufacturing method of the polyamide resin composition as described in [6] which contains the component unit to perform 50-100 mol%.
[8] The production of the polyamide resin composition according to [7], wherein the component unit derived from the linear aliphatic diamine having 4 to 8 carbon atoms is a component unit derived from 1,6-hexanediamine. Method.
[9] The method for producing a polyamide resin composition according to any one of [1] to [8], wherein the carbon fiber (B) is a PAN-based carbon fiber.
[10] The method for producing a polyamide resin composition according to any one of [1] to [9], wherein an average fiber length of the supplied carbon fiber (B) is 2 to 20 mm.
[11] Any one of [1] to [10], further including a step of cooling and solidifying the melt-kneaded product to which at least a part of the remaining carbon fiber (B) is further supplied and then cutting to obtain pellets. A process for producing a polyamide resin composition according to claim 1.

2nd of this invention is related with the manufacturing method of the molded object which has the following structures.
[12] A method for producing a molded body, comprising a step of producing a polyamide resin composition by the production method according to any one of [1] to [11] and a step of shaping the obtained polyamide resin composition. .
[13] The method for producing a molded body according to [12], wherein the molded body has a bending strength of 470 MPa or more.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the polyamide resin composition which can provide the molded object which has high mechanical strength (rigidity) can be provided.

FIG. 1 is a schematic diagram showing a configuration of a polyamide resin composition manufacturing apparatus 100 according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1. Manufacturing method of polyamide resin composition The manufacturing method of the polyamide resin composition according to the present embodiment includes 1) a step of melting the polyamide resin (A), and 2) carbon fiber (B) in the molten polyamide resin (A). A part of the carbon fiber (B) is added to the melt kneaded product of the polyamide resin (A) and the carbon fiber (B). Supplying and melt-kneading.

  Steps 1) to 3) can be performed using any kneader. Among these, it is preferable to use an extruder. An extruder is not specifically limited, For example, a single screw extruder, a twin screw extruder, etc. can be used. Among these, a twin screw extruder is preferable from the viewpoint of high kneadability and high dispersion of the carbon fiber (B).

  First, the structure of the manufacturing apparatus used for the manufacturing method of a polyamide resin composition is demonstrated.

(Manufacturing equipment)
FIG. 1 is a schematic diagram showing a configuration of a polyamide resin composition manufacturing apparatus 100 according to the present embodiment.

  The manufacturing apparatus 100 includes an extruder 10, a strand conveyor 30, and a strand cutter 50.

  As shown in FIG. 1, the extruder 10 includes a cylinder 11 and a screw (not shown) housed therein. Moreover, the extruder 10 has the main feeder 13, the 1st side feeder 15, the 2nd side feeder 17, and the die | dye 19 which were arrange | positioned at the cylinder 11 in this order. Then, the polyamide resin (A) and the carbon fiber (B) are respectively supplied into the cylinder 11 from a predetermined feed port and melt-kneaded in the cylinder 11 to produce a polyamide resin composition. .

  The main feeder 13 is a supply unit for supplying the polyamide resin (A) into the cylinder 11, and has a main feed port 13A disposed in the cylinder 11 and a feeder 13B connected thereto.

  The main feed port 13 </ b> A is a supply port for supplying the polyamide resin (A) disposed on the upstream side in the pushing direction of the cylinder 11.

  The feeder 13B can be a constant mass or constant volume supply device for conveying the polyamide resin (A) to the main feed port 13A. The fixed amount supply device may be any of a belt type, a screw type, a vibration type and the like.

  The first side feeder 15 is a supply unit for supplying a part of the carbon fiber (B) into the cylinder 11. The first side feeder 15 has a first side feed port 15A disposed in the cylinder 11 and a feeder 15B connected thereto.

  The first side feed port 15A is a supply port for supplying a part of the carbon fiber (B) disposed on the downstream side of the cylinder 11 in the extrusion direction of the main feed port 13A. The interval between the first side feed port 15A and the main feed port 13A (interval in the extrusion direction) depends on the screw rotation speed and the like, but when the screw length is L, it is about 0.34L to 0.75L ( For example, it is preferable that it is 700-1500 mm. The interval between the first side feed port 15A and the main feed port 13A refers to the interval between the center line of the first side feed port 15A and the center line of the main feed port 13A in the extrusion direction.

  The feeder 15B is a constant mass or constant volume supply device similar to that described above for conveying the carbon fiber (B) to the first side feed port 15A.

  The second side feeder 17 is a supply part for supplying at least a part (preferably all the remaining) of the carbon fiber (B) into the cylinder 11, and the second side feed port 17 </ b> A disposed in the cylinder 11. And a feeder 17B connected thereto.

  The second side feed port 17A is a supply port for supplying at least a part of the remaining carbon fiber (B), which is arranged on the downstream side of the cylinder 11 in the extrusion direction of the first side feed port 15A. The interval (interval in the extrusion direction) between the second side feed port 17A and the first side feed port 15A is about 0.24L to 0.55L (for example, about 500 to 1100mm), although it depends on the screw speed and the like. It is preferable. The interval between the second side feed port 17A and the first side feed port 15A refers to the interval between the center line of the second side feed port 17A and the center line of the first side feed port 15A in the extrusion direction.

  The feeder 17B is a constant mass or constant volume supply device similar to that described above for conveying the carbon fiber (B) to the second side feed port 17A.

  The number of side feeders (or side feed ports) may be two or more, and is not particularly limited. The number of side feeders (or side feed ports) is as in the present embodiment from the viewpoint that the carbon fiber (B) can be divided and supplied without increasing the manufacturing cost and the mass average fiber length can be easily controlled. Two are preferable.

  The die 19 discharges a polyamide resin composition obtained by melt-kneading in the cylinder 11. The type of the die 19 can be appropriately selected according to the discharge shape.

  The extruder 10 preferably has kneading zones (kneading sections) before and after the supply of the carbon fibers (B) from the first side feed port 15A and the second side feed port 17A. That is, the polyamide resin (A) can be sufficiently melted in the kneading zone before the carbon fiber (B) is supplied. Moreover, the kneading of the molten polyamide resin (A) and the carbon fiber (B) in the kneading zone after the supply of the carbon fiber (B) suppresses breakage of the carbon fiber (B), and the mass average The fiber length can be controlled. Thereby, the polyamide resin composition which is excellent in dispersibility and distribution can be obtained while maintaining the average fiber length of the carbon fiber (B).

  That is, as shown in FIG. 1, the extruder 10 includes a plasticizing portion 21 (kneading zone) disposed between the main feed port 13A and the first side feed port 15A, and the first side feed port 15A. First kneading part 23 (kneading zone) disposed between the second side feed port 17A and the second kneading part 25 (kneading) disposed between the second side feed port 17A and the die 19. Zone).

  The shape of the screw is not particularly limited. As a screw element which determines the shape of a screw, there are usually a conveying element such as a forward flight and a kneading element. The shape of the screw in the first kneading section 23 and the second kneading section 25 of the extruder 10 may be configured by a known kneading section element, and may be appropriately selected according to the nature of the resin and the type of filler. For example, when the extruder 10 is a twin-screw extruder, the screw shapes in the first kneading unit 23 and the second kneading unit 25 are screw elements such as reverse flight, seal ring, forward kneading disk, and reverse kneading disk. One or more of them can be combined.

  Further, the extruder 10 may further include a vent port 27 and a decompression device 29 that are disposed in the cylinder 11 as necessary (see FIG. 1).

  When performing vacuum exhaust through the vent port 27, it is preferable that the screw further has a seal portion (not shown) for completely filling the molten resin composition in the cylinder 11. In the case of a twin-screw extruder, the shape of the screw constituting the seal portion is suitably used in addition to reverse flight, such as a seal ring, reverse kneading, or the like that has a pressure increasing capability with respect to screw rotation. Further, elements such as a kneading disk may be combined as necessary.

  The position of the vent port 27 is not particularly limited, but can be disposed downstream of the first side feed port 15A, specifically, between the first side feed port 15A and the second side feed port 17A (see FIG. 1). ). That is, in the case where vacuum exhaust is performed between the first side feed port 15A and the second side feed 17A, the seal portion is preferably disposed between the vent port 27 and the second side feed port 17A.

  The screw diameter (D), screw length / screw diameter ratio (L / D), screw shape, screw rotation speed, driving force and heating / cooling capacity of the extruder 10 are not particularly limited, and the melt kneading is favorably performed. What can be implemented may be selected.

  Although screw diameter D should just be able to implement melt-kneading satisfactorily, it can be 20-70 mm, for example.

  L / D (screw length L / screw diameter D) of the extruder 10 is preferably 20 or more, more preferably 20 to 80, and still more preferably 25 to 65.

  Among these, L / D of the 1st kneading part 23 and the 2nd kneading part 25 depends on the shape of the screw and the operating conditions, but is preferably 2 to 25 respectively. When the L / D of the first kneading unit 23 and the second kneading unit 25 is 2 or more, the carbon fiber (B) is appropriately bent, and the fluidity is not easily lowered. If the L / D of the first kneading unit 23 and the second kneading unit 25 is 25 or less, the heat generation does not become too large, and it is easy to suppress problems such as resin decomposition, carbonization, and gas generation. The L / D of the first kneading unit 23 and the second kneading unit 25 is more preferably 5 to 15 from the above viewpoint.

  The strand conveyor 30 is an apparatus that cools the molten polyamide resin composition discharged from the die 19 of the extruder 10 while taking it into a strand shape.

  The strand cutter 50 is a device that cuts a strand-like polyamide resin composition obtained by cooling and solidifying with a strand conveyor 30 into a predetermined size.

  Next, the manufacturing method of the polyamide resin composition using the manufacturing apparatus 100 is demonstrated.

(Manufacturing method of polyamide resin composition)
As described above, the method for producing the polyamide resin composition according to the present embodiment includes: 1) supplying the polyamide resin (A) from the main feed port 13A of the extruder 10 and melting the polyamide resin (A); 2) A step of supplying a part of the carbon fiber (B) from the first side feed port 15A and melt-kneading the molten polyamide resin (A), and 3) a carbon fiber (B) from the second side feed port 15A. And a step of melt-kneading the molten kneaded product obtained in 2).

Step 1) The polyamide resin (A) is supplied from the main feed port 13A of the extruder 10. Since the polyamide resin (A) is basically the same as the polyamide resin (A) contained in the polyamide resin composition described later, the details will be described later. Supply of the polyamide resin (A) to the main feed port 13A can be performed by a feeder 13B.

  Next, the plasticizing part 21 is kneaded while melting the polyamide resin (A).

  The melt kneading temperature may be set to a temperature not lower than the melting point (Tm) of the polyamide resin (A) and not higher than the thermal decomposition temperature of the polyamide resin (A), and may be, for example, (Tm + 10) ° C. or higher. Specifically, the temperature is preferably 200 to 350 ° C. When the melt-kneading temperature is 200 ° C. or higher, the shear stress applied to the carbon fiber (B) can be easily reduced, and excessive breakage of the carbon fiber (B) can be suppressed. Further, when the melt kneading temperature is 350 ° C. or lower, the thermal decomposition of the polyamide resin (A) can be highly suppressed. The melt kneading temperature can be adjusted as the temperature of the cylinder 11 (cylinder temperature).

Step 2) Part of the carbon fiber (B) is supplied into the cylinder 11 from the first side feed port 15 </ b> A of the extruder 10. Supply of the carbon fiber (B) to the first side feed port 15A can be performed by the feeder 15B. Thereby, a part of carbon fiber (B) is supplied to the melted polyamide resin (A) obtained in the step 1).

(Carbon fiber (B))
Although carbon fiber (B) to be supplied is not particularly limited, PAN-based carbon fiber (B-1) using polyacrylonitrile-based resin as a raw material, or pitch-based carbon fiber (B-2) using mesophase pitch as a raw material. It can be.

  As described above, the PAN-based carbon fiber (B-1) is a PAN-based carbon fiber (B-1) made of substantially only carbon, which is produced by infusibilizing and carbonizing a fiber made of polyacrylonitrile resin. (Monofilament). The PAN-based carbon fiber (B-1) can impart high mechanical strength to the obtained molded body while reducing the specific gravity of the obtained polyamide resin composition (for example, pellets) and the molded body.

  The average fiber diameter (diameter of the fiber cross section) of the PAN-based carbon fiber (B-1) is preferably 1 to 20 μm, more preferably 4 to 15 μm, and further preferably 5 to 8 μm. When the fiber diameter of the PAN-based carbon fiber (B-1) is 1 μm or more, the specific surface area of the PAN-based carbon fiber (B-1) can be reduced, and the moldability is excellent. Moreover, when the fiber diameter of the PAN-based carbon fiber (B-1) is 20 μm or less, the handleability is excellent, the aspect ratio of the PAN-based carbon fiber (B-1) can be increased, and the mechanical properties of the molded body. Excellent.

  The average fiber diameter of the PAN-based carbon fibers (B-1) can be obtained as an average value by measuring the fiber diameters of 10 arbitrarily selected PAN-based carbon fibers (B-1) with an electron microscope. . The fiber diameter of the PAN-based carbon fiber (B-1) is the maximum ferret diameter of the cross section of the single fiber.

  As described above, the pitch-based carbon fiber (B-2) is a mesophase pitch (a resin partially showing a liquid crystal structure produced by processing petroleum tar, coal tar, or the like, or an artificially synthesized mesophase pitch). This is a pitch-based carbon fiber (B-2) (single fiber) formed by spinning, infusibilizing, and further carbonizing and having a graphite crystal structure that is highly developed in the fiber axis direction and consisting essentially of carbon. The pitch-based carbon fiber (B-2) can impart high thermal conductivity to the molded body while suppressing thermal expansion of the obtained polyamide resin composition (for example, pellets) and the molded body.

  The fiber diameter of the pitch-based carbon fiber (B-2) is preferably 4 to 15 μm, and more preferably 7 to 11 μm. When the fiber diameter of the pitch-based carbon fiber (B-2) is 4 μm or more, the pitch-based carbon fiber (B-2) is easily manufactured, and the fiber diameter of the pitch-based carbon fiber (B-2) is 15 μm or less. When it is, it is excellent in handleability. The fiber diameter of the pitch-based carbon fiber (B-2) can be measured by the same method as described above.

  Carbon fiber (B) may be used by 1 type and may use 2 or more types together. For example, from the viewpoint of obtaining a molded body having both excellent thermal conductivity and excellent mechanical properties, the PAN-based carbon fiber (B-1) and the pitch-based carbon fiber (B-2) may be used in combination. . In this invention, it is preferable that a carbon fiber (B) contains a PAN type carbon fiber (B-1) at least from a viewpoint of obtaining a molded object with high mechanical strength easily.

  The form of the carbon fiber (B) to be supplied is not particularly limited, but is usually supplied as a bundle (strand) of a plurality of carbon fibers (B) from the viewpoint of dispersibility and handling properties. The number of carbon fibers (B) may be, for example, 1000 to 100,000, preferably 3000 to 80000. The form of the converging body is not particularly limited, and may be a long fiber, a chopped strand, or the like. Of these, chopped strands are preferred because of good moldability.

  The length of the chopped strand (mass average fiber length) is usually preferably 1 to 20 mm, more preferably 2 to 20 mm, and still more preferably 5 to 10 mm. When the mass average fiber length is not less than a certain value, it is easy to impart high mechanical strength to the obtained molded product, and when it is not more than a certain value, excessive breakage of the carbon fiber (B) during melt-kneading can be easily suppressed.

The mass average fiber length of the chopped strand can be measured by the following method. That is, the fiber length of 10 arbitrarily selected chopped strands is measured with an electron microscope. And when the measured fiber length is set to L, it applies to following formula (1) and can calculate and obtain | require mass average fiber length.
Mass average fiber length = (ΣL ² ) / (ΣL) (1)

  As described above, the bundle of carbon fibers (B) is obtained by bundling a plurality of carbon fibers (B) with a sizing agent. The sizing agent can be a urethane-based emulsion, an epoxy-based emulsion, a nylon-based emulsion or the like from the viewpoint of increasing mechanical strength. The adhesion amount of the sizing agent is preferably 0.3 to 5% by mass and more preferably 1.0 to 3.0% by mass with respect to the carbon fiber (B).

  The strand strength of the bundle of carbon fibers (B) is not particularly limited, and may be 3.0 to 7.0 GPa. However, the toughness of the obtained molded body is hardly impaired, and the aspect in which the present invention is more effective. Then, it is preferable that it is 3.5-5GPa. The strand strength of the bundle of carbon fibers (B) can be measured by a tensile test in accordance with JIS R7601.

  The amount of carbon fiber (B) supplied from the first side feed port 15A in the step 2) is X, and the amount of carbon fiber (B) supplied from the second side feed port 17A in the step 3) is Y. X / Y = 45/55 to 80/20 (mass ratio) is preferable. Thereby, if the supply amount of the carbon fiber (B) from the first side feed port 15A and the second side feed port 17A is within the above range, it will not be bent excessively or insufficiently folded. The carbon fiber (B) can be adjusted to a predetermined mass average fiber length and further to a predetermined fiber length distribution. From the above viewpoint, X / Y = 50/50 to 80/20 (mass ratio) is preferable, and 60/40 to 80/20 (mass ratio) is more preferable. In addition, the sum total of the supply amount of carbon fiber (B) is adjusted so that content of carbon fiber (B) in the obtained polyamide resin composition may become the range mentioned later.

  Next, in the first kneading unit 23, the melted polyamide resin (A) and a part of the carbon fiber (B) are melt-kneaded. The melt kneading temperature can be the same as described above.

Step 3) At least a part (preferably the remaining part) of the carbon fiber (B) is supplied from the second side feed port 17A. The carbon fiber (B) can be supplied to the second side feed port 17A by the feeder 17B. Thereby, at least a part of the remaining carbon fiber (B) is supplied to the melt-kneaded product (polyamide resin (A) and a part of the carbon fiber (B)) obtained in the step 2). To do.

  The supply amount of the carbon fiber (B) from the second side feed port 17A is adjusted so that X / Y falls within the above range.

  Next, in the second kneading unit 25, the polyamide resin (A) to which a part of the carbon fiber (B) is added and at least a part (preferably the remaining part) of the carbon fiber (B) are melt-kneaded. The melt kneading temperature can be the same as described above.

  Through the steps 1) to 3), the number of rotations of the screw is not particularly limited as long as it can sufficiently perform melt-kneading. For example, in the case of a co-directional twin-screw extruder, it may be 100 to 300 rpm. preferable. When the screw rotation speed of the extruder 10 is 100 rpm or more, the dispersibility of the carbon fiber (B) can be highly enhanced. Moreover, the excessive breakage of carbon fiber (B) can be suppressed highly as the screw rotation speed of the extruder 10 is 300 rpm or less.

  The melt-kneaded material thus obtained is discharged from the die 19. Then, the discharged polyamide resin composition in a molten state can be cooled and solidified to obtain a polyamide resin composition.

  The form of the polyamide resin composition to be obtained is not particularly limited, and may be in the form of pellets or powder (powder).

  That is, in the present embodiment, 4) a step of cooling and solidifying the obtained molten resin composition and then cutting to obtain pellets can be further performed.

Step 4) Specifically, the melt-kneaded material discharged from the die 19 is cooled and solidified while being taken up in a strand shape, for example, in a strand conveyor 30 (see FIG. 1). Then, the obtained strand-like polyamide resin composition can be cut into a predetermined size with a strand cutter 50 to obtain a pellet-like polyamide resin composition.

(effect)
Thus, in the present embodiment, the carbon fibers (B) are separately supplied at a predetermined ratio from at least two locations of the first side feed port 15A and the second side feed port 17A. And after melt-kneading the polyamide resin (A) and a part of the carbon fibers (B) between the first side feed port 15A and the second side feed port 17A (first kneading part 23); The remaining carbon fiber (B) is further added to the melt-kneaded product of the polyamide resin (A) and a part of the carbon fibers (B) between the two-side feed port 17A and the die 19 (second kneading part 25). Melt and knead. Thereby, the average fiber length can be adjusted to an appropriate range without causing the carbon fiber (B) to be broken or insufficiently broken during melt kneading. Specifically, it is considered that by dividing and supplying the carbon fiber (B), the dispersibility of the carbon fiber (B) in the polyamide resin (A) is increased, and the adhesion interface between the two is increased. Thereby, it is considered that the adhesion strength between the polyamide resin (A) and the carbon fiber (B) is increased, and a molded product having high strength can be provided.

  In addition, in this Embodiment, although the example which each supplies carbon fiber (B) from two side feed ports was shown, it is not limited to this, Carbon fiber (B) is each transmitted from three or more side feed ports You may supply. For example, when the extruder 10 further has a third side feed port (not shown) arranged on the downstream side in the extrusion direction of the second side feed port 17A, the carbon fiber (B) from the first side feed port 15A It is only necessary that the supply amount X and the supply amount Y of the carbon fiber (B) from the second side feed port 17A satisfy the aforementioned X / Y mass ratio.

  Moreover, although the example which manufactures a pellet-like polyamide resin composition was shown in this Embodiment, it is not limited to this, You may manufacture the polyamide resin composition of a powder form (pulverized material).

  Next, the polyamide resin composition obtained by the method for producing a polyamide resin composition according to the present embodiment will be described.

2. Polyamide resin composition The polyamide resin composition according to the present embodiment includes a polyamide resin (A) and carbon fibers (B).

2-1. Polyamide resin (A)
The melting point (Tm) of the polyamide resin (A) is preferably 290 to 340 ° C. When the melting point of the polyamide resin (A) is 290 ° C. or higher, high heat resistance is easily imparted to the molded body of the polyamide resin composition. Further, when the melting point of the polyamide resin (A) is 340 ° C. or lower, it is not necessary to excessively increase the molding temperature, and therefore, thermal decomposition of the resin and other components during melt polymerization or melt molding can be suppressed. The melting point of the polyamide resin (A) is more preferably 300 to 330 ° C.

  The glass transition temperature (Tg) of the polyamide resin (A) measured by a differential scanning calorimeter (DSC) is preferably 80 to 150 ° C, and more preferably 90 to 135 ° C.

  The melting point (Tm) and glass transition temperature (Tg) of the polyamide resin (A) can be measured with a differential scanning calorimeter (for example, DSC220C type, manufactured by Seiko Instruments Inc.). Specific measurement conditions may be the same as in the examples described later.

  The melting point (Tm) and the glass transition temperature (Tg) of the polyamide resin (A) can be adjusted by, for example, the composition of the component unit (a1) derived from dicarboxylic acid described later. In order to increase the melting point of the polyamide resin (A), for example, the content ratio of the component units derived from terephthalic acid may be increased.

  The polyamide resin (A) includes a component unit (a1) derived from dicarboxylic acid and a component unit (a2) derived from diamine.

[Component unit derived from dicarboxylic acid (a1)]
The component unit (a1) derived from dicarboxylic acid preferably includes at least a component unit derived from terephthalic acid. The polyamide resin (A) containing a component unit derived from terephthalic acid has high crystallinity and can impart good heat resistance and mechanical strength (tensile strength, rigidity) to the molded body.

  Specifically, the component unit (a1) derived from dicarboxylic acid is composed of 20 to 100 mol% of component units derived from terephthalic acid, 0 to 80 mol% of component units derived from aromatic dicarboxylic acid other than terephthalic acid, and More preferably, it contains at least one of 0 to 40 mol% of component units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, 55 to 100 mol% of component units derived from terephthalic acid, and other than terephthalic acid More preferably, it contains 0 to 45 mol% of component units derived from aromatic dicarboxylic acid. However, the total amount of the component units (a1) derived from dicarboxylic acid is 100 mol%.

  Examples of terephthalic acid include terephthalic acid and terephthalic acid esters (terephthalic acid alkyl esters having 1 to 4 carbon atoms).

  Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methyl terephthalic acid, naphthalene dicarboxylic acid and esters thereof, and preferably isophthalic acid.

  The aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably an aliphatic dicarboxylic acid having 6 to 12 carbon atoms. Examples thereof include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, and adipic acid. 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid, suberic acid and the like, preferably adipic acid .

  In the component unit (a1) derived from dicarboxylic acid, the molar ratio between the component unit derived from terephthalic acid and the component unit derived from an aromatic dicarboxylic acid other than terephthalic acid (preferably isophthalic acid) is derived from terephthalic acid. Component unit / component unit derived from aromatic dicarboxylic acid other than terephthalic acid (preferably isophthalic acid) = 55/45 to 80/20 is preferable, and 60/40 to 85/15 is more preferable. When the amount of the component unit derived from terephthalic acid is a certain level or more, the heat resistance and mechanical strength of the obtained molded body are easily increased. If the amount of the component unit derived from terephthalic acid is below a certain level, the toughness of the molded body is difficult to be impaired.

  The component unit (a1) derived from dicarboxylic acid may further include a component unit derived from alicyclic dicarboxylic acid as long as the effects of the present invention are not impaired. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and the like.

[Component unit derived from diamine (a2)]
The component unit (a2) derived from a diamine includes at least one of a component unit derived from an aliphatic diamine having 4 to 15 carbon atoms and a component unit derived from an alicyclic diamine having 4 to 20 carbon atoms.

  The component unit derived from an aliphatic diamine having 4 to 15 carbon atoms preferably includes a component unit derived from a linear aliphatic diamine having 4 to 8 carbon atoms.

  The linear aliphatic diamine having 4 to 8 carbon atoms is more preferably a linear aliphatic diamine having 6 to 8 carbon atoms. Examples of the linear aliphatic diamine having 4 to 8 carbon atoms include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-octanediamine and the like. 4-8 linear alkylenediamines are included. Among these, 1,6-diaminohexane is preferable. One type of component unit derived from a linear aliphatic diamine having 4 to 8 carbon atoms may be included, or two or more types may be included.

  The component unit derived from an aliphatic diamine having 4 to 15 carbon atoms may further include a component unit derived from a branched aliphatic diamine having 4 to 15 carbon atoms. Examples of the branched aliphatic diamine having 4 to 15 carbon atoms include 2-methyl-1,8-octanediamine and 2-methyl-1,5-pentanediamine. Such a branched aliphatic diamine can moderately lower the crystallinity of the polyamide resin (A).

  Examples of alicyclic diamines having 4 to 20 carbon atoms include 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) Cyclohexane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis (4-aminocyclohexyl) methane, bis (4-aminocyclohexyl) propane, 4,4′-diamino-3,3′-dimethyldicyclohexylpropane, 4, 4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl -5,5'-dimethyldicyclohexylpropane, α, α'-bis (4-aminocyclohexyl) -p-diiso Propylbenzene, α, α'-bis (4-aminocyclohexyl) -m-diisopropylbenzene, α, α'-bis (4-aminocyclohexyl) -1,4-cyclohexane, α, α'-bis (4-aminocyclohexyl) ) -1,3-cyclohexane and the like. Among these, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl) methane, and 4,4′-diamino-3,3′-dimethyldicyclohexylmethane are preferable; 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 1,3-bis (aminocyclohexyl) methane, and 1,3-bis (aminomethyl) cyclohexane are more preferable.

  The total content of component units derived from an aliphatic diamine having 4 to 15 carbon atoms and component units derived from an alicyclic diamine having 4 to 20 carbon atoms (preferably an aliphatic diamine having 4 to 15 carbon atoms) The content of the derived component unit) is preferably 50 mol% or more based on the total amount of the component unit (a2) derived from diamine. When the total content is 50 mol% or more, the water resistance of the obtained molded product is likely to increase. Total content of component units derived from aliphatic diamine having 4 to 15 carbon atoms and component units derived from alicyclic diamine having 4 to 20 carbon atoms (preferably linear fat having 4 to 8 carbon atoms) The content of the group diamine component unit) is more preferably 70 mol% or more, further preferably 90 mol% or more, and may be 100 mol%. However, the total amount of the component unit (a2) derived from diamine is 100 mol%.

  The component unit (a2) derived from diamine may further include a component unit derived from another diamine as long as the effects of the present invention are not impaired. Examples of other diamines include aromatic diamines. Examples of the aromatic diamine include metaxylylenediamine. Content of the component unit derived from other diamine is 50 mol% or less with respect to the total amount of the component unit (a2) derived from diamine, Preferably it can be 40 mol% or less.

  In a specific example of the polyamide resin (A), the component unit (a2) derived from dicarboxylic acid is a component unit derived from terephthalic acid and a component unit derived from isophthalic acid, and is derived from a linear aliphatic diamine. Resin in which the component unit is 1,6-diaminohexane; the component unit (a2) derived from dicarboxylic acid is a component unit derived from terephthalic acid and a component unit derived from adipic acid, and a linear aliphatic diamine A resin in which the component unit derived from is 1,6-diaminohexane is included. Only one type of polyamide resin (A) may be included, or two or more types may be included.

  The intrinsic viscosity [η] of the polyamide resin (A) measured in a 96.5% sulfuric acid at a temperature of 25 ° C. is preferably 0.7 to 1.6 dl / g, and preferably 0.8 to 1.2 dl. / G is more preferable. When the intrinsic viscosity [η] of the polyamide resin (A) is a certain level or more, the strength of the molded body is likely to be sufficiently increased. When the intrinsic viscosity [η] is below a certain level, the fluidity during molding of the resin composition is unlikely to be impaired. The intrinsic viscosity [η] is adjusted by the molecular weight of the polyamide resin (A).

For the intrinsic viscosity of the polyamide resin (A), 0.5 g of the polyamide resin (A) is dissolved in 50 ml of a 96.5% sulfuric acid solution to prepare a sample solution. The flow down time of the sample liquid can be measured using an Ubbelohde viscometer under the condition of 25 ± 0.05 ° C., and the obtained value can be calculated by applying the following equation.
[Η] = ηSP / [C (1 + 0.205ηSP)]
In the above formula, each algebra or variable represents the following.
[Η]: Intrinsic viscosity (dl / g)
ηSP: specific viscosity C: sample concentration (g / dl)

ηSP is obtained by the following equation.
ηSP = (t−t0) / t0
t: Number of seconds that the sample solution flows (seconds)
t0: The number of seconds (seconds) when blank sulfuric acid flows

  In the polyamide resin (A), from the viewpoint of thermal stability at the time of compounding or molding, at least a part of molecular end groups may be sealed with a terminal sealing agent. The terminal amino group amount of the polyamide resin (A) is preferably 0.1 to 300 mmol / kg, more preferably 20 to 300 mmol / kg, and more preferably 35 to 200 mmol / kg.

The amount of terminal amino groups can be measured by the following method. 1 g of polyamide resin is dissolved in 35 mL of phenol, and 2 mL of methanol is mixed to obtain a sample solution. Then, using thymol blue as an indicator, the sample solution was titrated using a 0.01 N aqueous HCl solution until the color changed from blue to yellow, and the terminal amino group amount ([NH ₂ ], unit: mmol / kg).

  The polyamide resin (A) can be produced by the same method as known polyamide resins, and can be produced, for example, by polycondensation of dicarboxylic acid and diamine in a uniform solution. Specifically, a low-order condensate is obtained by heating a dicarboxylic acid and a diamine in the presence of a catalyst as described in WO 03/085029. It can be produced by applying a shear stress to the melt to cause polycondensation.

  When adjusting the intrinsic viscosity of the polyamide resin (A), it is preferable to add a terminal blocking agent (molecular weight adjusting agent) to the reaction system. The end-capping agent can be, for example, a monocarboxylic acid or a monoamine. Examples of the monocarboxylic acid include aliphatic monocarboxylic acids having 2 to 30 carbon atoms, aromatic monocarboxylic acids, and alicyclic monocarboxylic acids. These terminal blocking agents can adjust the amount of terminal amino groups of the polyamide resin (A) while adjusting the molecular weight of the polyamide resin (A). The aromatic monocarboxylic acid and the alicyclic monocarboxylic acid may have a substituent in the cyclic structure portion.

  Examples of aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid It is. Examples of the aromatic monocarboxylic acid include benzoic acid, toluic acid, naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid and phenylacetic acid. Examples of the alicyclic monocarboxylic acid include cyclohexanecarboxylic acid.

  The terminal blocking agent is added to the reaction system of dicarboxylic acid and diamine. The addition amount is preferably 0.07 mol or less, more preferably 0.05 mol or less, with respect to 1 mol of the total amount of dicarboxylic acid. By using the molecular weight adjusting agent in such an amount, at least a part of the molecular weight adjusting agent is taken into the polyamide, whereby the intrinsic viscosity [η] of the polyamide resin (A) is easily adjusted within a desired range.

  The content of the polyamide resin (A) is preferably 40 to 90 parts by mass when the total of the polyamide resin (A) and the carbon fiber (B) is 100 parts by mass. When the content of the polyamide resin (A) is 90 parts by mass or less, high strength (rigidity) can be imparted to the resin composition. When the content of the polyamide resin (A) is 40 parts by mass or more, the resin composition hardly undergoes a significant decrease in injection moldability and compound productivity. The content of the polyamide resin (A) is more preferably 50 to 70 parts by mass and 50 to 60 parts by mass when the total of the polyamide resin (A) and the carbon fiber (B) is 100 parts by mass. More preferably.

2-2. Carbon fiber (B)
The carbon fiber (B) is the carbon fiber (B) described above.

  The mass average fiber length of the carbon fibers (B) in the polyamide resin composition is preferably 0.1 to 0.9 mm. When the mass average fiber length of the carbon fibers (B) in the polyamide resin composition is 0.1 mm or more, the molded article is excellent in thermal conductivity and mechanical properties. Further, when the mass average fiber length of the carbon fibers (B) in the polyamide resin composition is 0.9 mm or less, the carbon fibers (B) are easily filled up to the details of the molded body. Thus, for example, when the carbon fiber (B) is supplied in the form of a bundle, the bundle of the carbon fiber (B) is opened at the time of production (compound) of the polyamide resin composition and appropriately broken. Thus, the carbon fiber (B) having the mass average fiber length as described above can be dispersed in the polyamide resin (A). From the above viewpoint, the mass average fiber length of the carbon fibers (B) in the polyamide resin composition is preferably 0.11 to 0.3 mm, and more preferably 0.12 to 0.25 mm.

The mass average fiber length of the carbon fibers (B) in the polyamide resin composition can be measured by the following method.
1) First, a polyamide resin composition (for example, pellets) is heated at 600 ° C. for 3 hours in an air atmosphere to remove the polyamide resin (A) and the like by thermal decomposition, and recover the remaining carbon fiber (B).
2) The fiber lengths of 100 recovered carbon fibers (B) are each measured with an optical microscope. When the measured fiber length is L, the mass average fiber length is calculated by applying to the following formula (1).
Mass average fiber length = (ΣL ² ) / (ΣL) (1)

  The mass average fiber length of the carbon fiber (B) in the polyamide resin composition is the mass average fiber length of the carbon fiber (B) as a raw material or the supply of the carbon fiber (B) in the manufacturing process of the polyamide resin composition described above. It can be adjusted by melt kneading conditions such as the method, screw speed of the extruder, and the discharge amount from the die.

  The content of the carbon fiber (B) is preferably 10 to 60 parts by mass when the total of the polyamide resin (A) and the carbon fiber (B) is 100 parts by mass. When the content of the carbon fiber (B) is 10 parts by mass or more, sufficient strength can be imparted to the molded article of the polyamide resin composition, and when it is 60 parts by mass or less, injection molding of the polyamide resin composition is performed. It is difficult to cause a significant decrease in performance and compound productivity. The content of the carbon fiber (B) is more preferably 30 to 50 parts by mass and 40 to 50 parts by mass when the total of the polyamide resin (A) and the carbon fiber (B) is 100 parts by mass. More preferably.

2-3. Other ingredients (C)
The polyamide resin composition of the present invention may further contain a component (C) other than the polyamide resin (A) and the carbon fiber (B) as necessary.

  Examples of other components (C) include colorants, fluidity improvers, antioxidants, metal deactivators, carbon black, nucleating agents, mold release agents, lubricants, antistatic agents, light stabilizers, UV absorbers Agents, fibrous fillers (such as glass fibers) other than carbon fibers (B), inorganic fillers, impact modifiers, melt tension improvers, flame retardants, and plasticizers. These components may be used individually by 1 type, and may use 2 or more types together. Of these, colorants, fluidity improvers, nucleating agents and the like are preferable. The total content of other components (C) is preferably 10% by mass or less, more preferably 5% by mass or less, based on the polyamide resin composition.

2-3-1. Colorant The polyamide resin composition of the present invention may contain a colorant from the viewpoint of coloring the molded article.

  The colorant is not particularly limited, but may be a pigment. Examples of pigments include inorganic pigments such as carbon black, alumina, titanium oxide, chromium oxide, iron oxide, zinc oxide, and barium sulfate; azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, anthraquinone pigments Organic pigments such as thioindigo pigments and indanthrene pigments.

  It is preferable that content of a coloring agent is 0.01-5 mass parts with respect to a total of 100 mass parts of a polyamide resin (A) and a carbon fiber (B), and is 0.1-2 mass parts. Is more preferable. When the pigment content is 0.01 parts by mass or more, the polyamide resin composition is easily colored sufficiently, and when it is 5 parts by mass or less, the moldability and the surface appearance of the molded body are hardly impaired.

2-3-2. Fluidity improver The polyamide resin composition of the present invention may further contain a fatty acid metal salt as a fluidity improver that improves the fluidity of the resin during injection molding.

  The fatty acid metal salt is effective for molding that requires high fluidity, such as molding of thin-walled small electric and electronic parts. The fatty acid metal salt may be a known compound. Examples of fatty acids constituting the fatty acid metal salt include montanic acid, behenic acid, stearic acid and the like. Examples of the metal salt constituting the fatty acid metal salt include lithium salt, calcium salt, barium salt, zinc salt, aluminum salt and the like. Preferred examples of the fatty acid metal salt include lithium salt, calcium salt, barium salt, zinc salt, and aluminum salt of montanic acid or behenic acid from the viewpoint of increasing fluidity during molding, and more preferred examples include montanic acid. Acid calcium is included.

  The content of the fluidity improver is preferably 0.1 to 5 parts by mass, and 0.1 to 3 parts by mass with respect to 100 parts by mass in total of the polyamide resin (A) and the carbon fiber (B). More preferably. When the content of the fluidity improver is within the above range, the fluidity at the time of molding the polyamide resin composition can be sufficiently enhanced.

2-3-3. Nucleating agent The polyamide resin composition of the present invention may further contain a nucleating agent from the viewpoint of promoting crystallization of the polyamide resin (A).

  Examples of the nucleating agent include metal salt compounds such as sodium 2,2-methylenebis (4,6 di-t-butylphenyl) phosphate, aluminum tris (pt-butylbenzoate), stearate; sorbitol compounds such as p-methylbenzylidene) sorbitol and bis (4-ethylbenzylidene) sorbitol; inorganic substances such as talc, calcium carbonate and hydrotalcite are included. Among these, talc is preferable from the viewpoint of easily increasing the crystallinity of the molded product. These nucleating agents may be used alone or in combination of two or more.

  The average particle diameter of the nucleating agent is preferably 0.1 to 30 μm. When the average particle diameter of the nucleating agent is 0.1 μm or more, the spherulites of the obtained molded body can be easily refined, and when the average particle diameter is 30 μm or less, the appearance of the surface of the molded body is hardly lowered. The average particle size of the nucleating agent is more preferably 0.5 to 25 μm, and further preferably 1.0 to 23 μm. The average particle diameter of the nucleating agent is an arithmetic average diameter obtained by measurement by a laser diffraction / scattering method, and is a volume average particle diameter (MV).

  The content of the nucleating agent is preferably 0.01 to 5 parts by mass, and 0.1 to 2 parts by mass with respect to 100 parts by mass in total of the polyamide resin (A) and the carbon fiber (B). Is more preferable. When the content of the nucleating agent is 0.01 parts by mass or more, the crystallization of the polyamide resin (A) can be sufficiently promoted, so that the spherulites of the obtained molded body are easily refined and are 5 parts by mass or less. And formability and surface appearance are hard to be impaired.

2-4. As described above, in the method for producing a polyamide resin composition of the present invention, the polyamide resin (A) is supplied from the main feed port 13A, and carbon is supplied from at least two locations of the first side feed port 15A and the second side feed port 17A. The fiber (B) is divided and supplied. Thereby, in the obtained polyamide resin composition, since the mass mean fiber length of carbon fiber (B) is adjusted appropriately, the molded object can have high mechanical strength (rigidity).

  Specifically, the bending strength of the molded article of the polyamide resin composition of the present invention is preferably 470 MPa or more, and more preferably 475 to 700 MPa. The bending strength can be measured by a bending test. Specific measurement conditions are the same as in the examples described later.

  The bending strength of the molded body of the polyamide resin composition can be adjusted by, for example, the strand strength / elastic modulus of the aggregate of carbon fibers (B) and the content of the carbon fibers (B).

  The form in particular of a polyamide resin composition is not restrict | limited, A pellet form may be sufficient and a powder form (powder form) may be sufficient. The polyamide resin composition is further molded by a known method and used as a molded body.

3. Manufacturing method of molded article and use thereof The molded article of the present invention can be obtained through a step of molding a polyamide resin composition obtained by the above-described manufacturing method. The molding method is not particularly limited, and may be a known molding method such as a compression molding method, an injection molding method, or an extrusion molding method.

  The obtained molded body can be used for various applications. Examples of the molded body of the polyamide resin composition of the present invention include a radiator grill, a rear spoiler, a wheel cover, a wheel cap, a cowl vent grill, an air outlet louver, an air scoop, a hood bulge, a sun roof, a sun roof rail, a fender, and the like. Automotive exterior parts such as back doors; cylinder head covers, engine mounts, air intake manifolds, throttle bodies, air intake pipes, radiator tanks, radiator supports, water pumps, water pump inlets, water pump outlets, thermostats Housing, cooling fan, fan shroud, oil pan, oil filter housing, oil filler cap, oil level gauge, oil Automotive engine compartment components such as motors, timing belts, timing belt covers and engine covers; fuel caps, fuel filler tubes, automotive fuel tanks, fuel sender modules, fuel cut-off valves, quick connectors, Automotive fuel components such as canisters, fuel delivery pipes and fuel filler necks; automotive drive components such as shift lever housings and propeller shafts; automotive chassis components such as stabilizer bars, linkage rods and engine mount brackets; Door regulator, door lock, door handle, outside door mirror stay, wiper and its parts, accelerator pedal, pedal module, Automotive functional parts such as hands, plastic screws, nuts, bushes, seal rings, bearings, bearing retainers, gears and actuators; wire harnesses / connectors, relay blocks, sensor housings, fuse parts, encapsulation, ignition coils and distribution Automotive electronics parts such as automotive caps; Fuel system parts for general equipment such as fuel tanks for general equipment (mowers, lawn mowers and chainsaws); Electrical and electronic parts such as connectors and LED reflectors; Building material parts; Industry Equipment parts: Various housings or exterior parts such as small housings (including housings such as personal computers and mobile phones) and exterior molded products are included.

  Since the molded article of the polyamide resin composition of the present invention has high strength (rigidity), it is a fuel tank for automobiles, quick connectors, bearing retainers, fuel tanks for general-purpose equipment, fuel caps, fuel filler necks, fuel sender modules. It is particularly suitable for automotive parts such as wheel caps, fenders or back doors.

  In the following, the present invention will be described with reference to examples. By way of example, the scope of the invention is not construed as limiting.

1. Material preparation (1) Polyamide resin (A)
The polyamide resin (PA6T6I) prepared in Synthesis Example 1 below was used.

(Synthesis Example 1)
1,6-diaminohexane 2800 g (24.1 mol), terephthalic acid 2774 g (16.7 mol), isophthalic acid 1196 g (7.2 mol), benzoic acid 36.6 g (0.30 mol), hypophosphorous acid Sodium monohydrate (5.7 g) and distilled water (545 g) were placed in an autoclave having an internal volume of 13.6 L and purged with nitrogen. Stirring was started from 190 ° C., and the internal temperature was raised to 250 ° C. over 3 hours. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. The reaction was continued for 1 hour as it was, and then the low-order condensate was extracted from the spray nozzle installed at the bottom of the autoclave. Then, after cooling to room temperature, the low-order condensate was pulverized to a particle size of 1.5 mm or less with a pulverizer and dried at 110 ° C. for 24 hours. The obtained low-order condensate had a water content of 4100 ppm and an intrinsic viscosity [η] of 0.15 dl / g.
Next, this low-order condensate was placed in a shelf-type solid phase polymerization apparatus, and after nitrogen substitution, the temperature was raised to 180 ° C. over about 1 hour and 30 minutes. Thereafter, the reaction was performed for 1 hour 30 minutes, and the temperature was lowered to room temperature. The intrinsic viscosity [η] of the obtained compound was 0.20 dl / g.
Thereafter, this compound was melt polymerized with a twin screw extruder having a screw diameter of 30 mm and L / D = 36 at a barrel set temperature of 330 ° C., a screw rotation speed of 200 rpm, and a resin feed rate of 6 kg / h to obtain a polyamide resin. (A-1) was obtained.
The intrinsic viscosity of the obtained polyamide resin (A-1) was 1.0 dl / g, the melting point (Tm) was 330 ° C., the glass transition temperature (Tg) was 125 ° C., and the amount of terminal amino groups was 30 mmol / kg. .

  The intrinsic viscosity [η], melting point (Tm), glass transition temperature (Tg) and terminal amino group content of the obtained polyamide resin (A) were measured by the following methods.

[Intrinsic viscosity [η]]
In accordance with JIS K6810-1977, 0.5 g of polyamide resin was dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The number of seconds of flowing of the obtained sample solution was measured under the condition of 25 ± 0.05 ° C. using an Ubbelohde viscometer. The intrinsic viscosity [η] of the polyamide resin was calculated by applying the measurement result to the following formula.
[Η] = ηSP / [C (1 + 0.205ηSP)]
ηSP = (t−t0) / t0
[Η]: Intrinsic viscosity (dl / g)
ηSP: specific viscosity C: sample concentration (g / dl)
t: Number of seconds that the sample solution flows (seconds)
t0: number of seconds (seconds) that the blank sulfuric acid flows down

[Melting point (Tm), glass transition temperature (Tg)]
The melting point (Tm) and glass transition temperature (Tg) of the polyamide resin were measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.). Specifically, about 5 mg of polyamide resin was sealed in an aluminum pan for measurement, and heated from room temperature to 350 ° C. at 10 ° C./min. In order to completely melt the resin, the resin was held at 350 ° C. for 5 minutes and then cooled to 30 ° C. at 10 ° C./min. After 5 minutes at 30 ° C., the second heating was performed to 350 ° C. at 10 ° C./min. The temperature (° C.) of the endothermic peak in the second heating was defined as the melting point (Tm) of the polyamide resin, and the displacement point corresponding to the glass transition was defined as the glass transition temperature (Tg).

[Terminal amino group content]
1 g of polyamide resin was dissolved in 35 mL of phenol, and 2 mL of methanol was mixed to prepare a sample solution. Then, using thymol blue as an indicator, the sample solution was titrated using a 0.01 N aqueous HCl solution until the color changed from blue to yellow, and the terminal amino group amount ([NH ₂ ], unit: mmol / kg).

(2) Carbon fiber (B)
TCTR06ULB6R (bundle of PAN-based carbon fiber) manufactured by Mitsubishi Chemical Corporation: average fiber diameter of PAN-based carbon fiber (single fiber): 6 μm, number of bundles: 60000, sizing agent adhesion amount: 2.5 mass%, strand strength: 4.8 GPa, PAN-based carbon fiber bundling chopped strand cut to an average fiber length of 6 mm

(3) Other components (C)
Calcium montanate (CS-8CP manufactured by Nitto Kasei Kogyo Co., Ltd.) (fatty acid metal salt)
Talc (average particle size 1.6μm) (nucleating agent)
Carbon black (pigment)

2. Preparation of polyamide resin composition [Example 1]
First, the manufacturing apparatus which has an extruder, a strand conveyor, and a strand cutter was prepared.

As an extruder, the same direction twin screw extruder (TEX30α, manufactured by Nippon Steel Works) was used. As shown in FIG. 1, the extruder 10 includes a main feeder 13 (main feed port 13A and feeder 13B) and a first side feeder 15 (first side feed port 15A and feeder 15B) from the upstream side in the extrusion direction. And the second side feeder 17 (second side feed port 17A and feeder 17B).
Further, this extruder has one location between the main feed port 13A and the first side feed port 15A, one location between the first side feed port 15A and the second side feed port 17A, and the second side feed port. A total of three kneading zones (kneading sections) are provided between 17 A and the die 19. The specific configuration of the extruder is as follows.
(Extruder configuration)
Extruder: manufactured by Nippon Steel Works Co., Ltd., co-directional twin screw extruder “TEX30α”, screw diameter D: 32 mm, L / D: 63.0, L / D of first kneading part 23: 5, 2 L / D of kneading part 25: 5)
Feeder 13B: Kubota biaxial screw feeder Feeder 15B: Kubota biaxial vibration feeder Feeder 17B: Kubota biaxial screw feeder Interval between main feed port 13A and first side feed port 15A: 730 mm (0.362 L) )
Distance between first side feed port 15A and second side feed port 17A: 500 mm (0.248 L)

  Using this extruder 10, polyamide resin (A) 57.3 mass% and other component (C) 2.7 mass% (calcium montanate: 0.4 mass%, talc: 0.6 mass%, carbon Black: 1.7% by mass) is supplied from the main feed port 13A, and 20% by mass of the carbon fiber (B) (a bundle of carbon fibers (B)) is supplied from the first side feed port 15A to the carbon fiber (B). 20% by mass was supplied from the second side feed port 17A, and melt kneading was performed under the conditions of a screw rotation speed of 150 rpm, a discharge rate of 25 kg / hour, and a cylinder temperature of 350 ° C.

  The obtained melt-kneaded product was extruded in a strand form from a die and naturally cooled while being taken out by the strand conveyor 30. Then, the strand was cut with the strand cutter 50, and the pellet-like polyamide resin composition was obtained.

[Example 2]
Example 1 except that the supply amount of the carbon fiber (B) from the first side feed port 15A and the supply amount of the carbon fiber (B) from the second side feed port 17A were changed as shown in Table 1. Similarly, a pellet-like polyamide resin composition was obtained.

[Comparative Example 1]
A pellet-like polyamide resin composition was obtained in the same manner as in Example 1 except that the screw rotation speed was changed to 150 rpm and 40% by mass of carbon fiber (B) was supplied all at once from the second side feed port 17A.

[Comparative Example 2]
A pellet-like polyamide resin composition was obtained in the same manner as in Example 1 except that 40% by mass of carbon fiber (B) was supplied all at once from the first side feed port 15A.

  The bending strength and bending elastic modulus of the obtained polyamide resin composition were evaluated by the following methods.

(Bending strength / flexural modulus)
The obtained polyamide resin composition was injection molded under the following conditions to obtain a 1/8 inch thick strip.
Molding machine: Sodick Plastic, Tupal TR40S3A
Molding machine cylinder temperature: melting point of polyamide resin (A) + 10 ° C.
Mold temperature: Tg of polyamide resin (A) + 20 ° C
The obtained test piece was allowed to stand for 24 hours in a nitrogen atmosphere at a temperature of 23 ° C. Next, a bending test was performed at a temperature of 25 ° C., 100 ° C., and a relative humidity of 50% at a bending tester: AB5 manufactured by NTSCO, span 51 mm, bending speed 12.7 mm / min. It was measured.

  Table 1 shows the production conditions and evaluation results of the polyamide resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2.

  As shown in Table 1, the polyamide resins of Examples 1 and 2 obtained by supplying a part of the carbon fiber (B) from the first side feed port 15A and supplying the remaining part from the second side feed port 17A. The composition includes the polyamide resin composition of Comparative Example 1 obtained by supplying all of the carbon fibers (B) in a lump from the second side feed port 17A, and all of the carbon fibers (B) in the first side feed port. It turns out that it has higher bending strength and elasticity modulus than the polyamide resin composition of the comparative example 2 obtained by supplying collectively from 15A.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the polyamide resin composition which can provide the molded object which has high mechanical strength (rigidity) can be provided.

DESCRIPTION OF SYMBOLS 10 Extruder 11 Cylinder 13 Main feeder 13A Main feed port 13B Feeder 15 1st side feeder 15A 1st side feed port 15B Feeder 17 2nd side feeder 17A 2nd side feed port 17B Feeder 19 Die 21 Plasticization part 23 1st kneading | mixing Unit 25 second kneading unit 27 vent port 29 pressure reducing device 30 strand conveyor 50 strand cutter 100 manufacturing device

Claims (13)

A method for producing a polyamide resin composition from an upstream side in the extrusion direction using an extruder having a main feed port, a first side feed port, and a second side feed port in this order,
Supplying the polyamide resin (A) from the main feed port and melting it;
Supplying a part of the carbon fiber (B) from the first side feed port, and melt-kneading the molten polyamide resin (A) and a part of the carbon fiber (B);
Further supplying at least a part of the remaining carbon fiber (B) from the second side feed port, a melt-kneaded product of the polyamide resin (A) and a part of the carbon fiber (B), and the carbon fiber Melting and kneading at least part of the remaining part of (B),
When the supply amount of a part of the carbon fiber (B) is X and the supply amount of at least a part of the carbon fiber (B) is Y, X / Y = 45/55 to 80/20 (mass ratio) )
A method for producing a polyamide resin composition. At least a part of the remaining carbon fiber (B) is the entire remaining carbon fiber (B).
The manufacturing method of the polyamide resin composition of Claim 1. When the length of the screw of the extruder is L,
The interval between the main feed port and the first side feed port is 0.34L to 0.75L,
An interval between the first side feed port and the second side feed port is 0.24L to 0.55L.
The manufacturing method of the polyamide resin composition of Claim 1 or 2. When the polyamide resin composition is 100 parts by mass of the total of the polyamide resin (A) and the carbon fiber (B),
40 to 90 parts by mass of the polyamide resin (A),
Including 10 to 60 parts by mass of the carbon fiber (B),
The manufacturing method of the polyamide resin composition as described in any one of Claims 1-3. The melting point (Tm) measured with a differential scanning calorimeter of the polyamide resin (A) is 290 to 340 ° C.,
The manufacturing method of the polyamide resin composition as described in any one of Claims 1-4. The polyamide resin (A) includes a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a diamine,
The component unit (a1) derived from the dicarboxylic acid is a component unit of 20 to 100 mol% derived from terephthalic acid with respect to a total of 100 mol% of the component unit (a1) derived from the dicarboxylic acid, and other than terephthalic acid At least one of 0 to 80 mol% of component units derived from aromatic dicarboxylic acid and 0 to 40 mol% of component units derived from aliphatic dicarboxylic acid having 4 to 20 carbon atoms,
The component unit (a2) derived from the diamine is a component unit derived from a linear aliphatic diamine having 4 to 8 carbon atoms and a total of 100 mol% of the component unit (a2) derived from the diamine, and A total of 50 to 100 mol% of at least one of component units derived from an alicyclic diamine having 4 to 20 carbon atoms,
The manufacturing method of the polyamide resin composition as described in any one of Claims 1-5. The component unit (a2) derived from the diamine is a component unit derived from the linear aliphatic diamine having 4 to 8 carbon atoms with respect to 100 mol% in total of the component unit (a2) derived from the diamine. Containing 50 to 100 mol%,
The manufacturing method of the polyamide resin composition of Claim 6. The component unit derived from the linear aliphatic diamine having 4 to 8 carbon atoms is a component unit derived from 1,6-hexanediamine.
The manufacturing method of the polyamide resin composition of Claim 7. The carbon fiber (B) is a PAN-based carbon fiber.
The manufacturing method of the polyamide resin composition as described in any one of Claims 1-8. The average fiber length of the supplied carbon fiber (B) is 2 to 20 mm.
The manufacturing method of the polyamide resin composition as described in any one of Claims 1-9. The method further includes a step of cooling and solidifying the melt-kneaded product to which at least a part of the remaining carbon fiber (B) is further supplied, and then cutting to obtain pellets.
The manufacturing method of the polyamide resin composition as described in any one of Claims 1-10. A step of producing a polyamide resin composition by the production method according to any one of claims 1 to 11,
Including a step of molding the obtained polyamide resin composition,
Manufacturing method of a molded object. The bending strength of the molded body is 470 MPa or more,
The manufacturing method of the molded object of Claim 12.

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