JP2011245755A - Method for producing resin-impregnated carbon fiber strand and carbon fiber pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strand formed by impregnating a carbon fiber with a semi-aromatic polyamide resin including a 1,9-nonane diamine unit as a diamine component, and to provide a long fiber pellet of a carbon fiber.SOLUTION: A method for producing a resin-impregnated carbon fiber strand formed by impregnating a carbon fiber with a semi-aromatic polyamide resin including a 1,9-nonane diamine unit as a diamine component, includes:filling a molten resin into an impregnation bath having a plurality of opening rollers arranged alternately obliquely with respect to the direction of a fiber bundle, and impregnating the carbon fiber with the resin while allowing the carbon fiber bundle to pass through in contact with the opening rollers in the impregnation bath for spread.

Description

  The present invention relates to a strand in which carbon fiber is impregnated with a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component, and a method for producing long fiber pellets.

Patent Documents 1 and 2 are related to a method for producing a fiber-reinforced pellet structure and a fiber-reinforced composite material. Patent Document 1 describes that a structure is obtained from a thermoplastic polymer having a melt viscosity of less than 30 Ns / m ² and a reinforcing filament, but there is no particular restriction on impregnation conditions.

  Patent Document 2 describes the viscosity of the melt and the tension when entering the surface of the first spreader, particularly in the method for producing a glass fiber composite material, and has a medium or considerably higher viscosity (higher than that of Patent Document 1). A method for producing fiber reinforced composites using plastic resins describes that the required filament pretension must be increased as the viscosity of the melt increases.

  However, for resin-impregnated strands using semi-aromatic polyamide resins containing 1,9-nonanediamine units as diamine components, and carbon fiber long fiber pellets, since the resin has high viscosity, a technique for improving the impregnation property is required. It was.

Japanese Patent Laid-Open No. 57-181852 JP-A-6-155593

  An object of the present invention is to provide a strand in which a carbon fiber is impregnated with a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component, and a carbon fiber long fiber pellet.

  The present invention is a method for producing a strand in which a carbon fiber is impregnated with a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component, and a plurality of fiber opening rollers are alternately inclined with respect to the fiber bundle traveling. This is a method for producing an impregnated strand of carbon fiber by filling a resin in a molten state in an impregnation bath disposed, and impregnating the resin while allowing the carbon fiber bundle to pass through a fiber opening roller in the impregnation bath and opening the fiber. Moreover, it is a manufacturing method of the semi-aromatic polyamide resin and carbon fiber long fiber pellet which contain a 1,9- nonanediamine unit as a diamine component from there.

  According to the present invention, a strand obtained by impregnating a carbon fiber with a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component, and a long fiber pellet of carbon fiber are preferably obtained with good stability. Moreover, the obtained strand and long fiber pellet are excellent in resin impregnation property, and there are few dry fibers in a strand or a pellet.

Examples of arrangement of spreader rollers Schematic diagram of opening device to pellet manufacturing device using the opening roller of FIG. Examples of arrangement of spreader rollers Schematic diagram of opening device to pellet manufacturing device using the opening roller of FIG.

[Carbon fiber]
The carbon fiber in the present invention is preferably composed of 1000 to 48000 monofilaments of carbon fiber having an average diameter of 5 to 10 μm. The average diameter of the carbon fiber is more preferably 6 to 8 μm. The tensile strength of the carbon fiber is preferably 3000 to 6000 MPa. The strength of the carbon fiber (MPa) = (single fiber strength (gf) / 1000) / single fiber cross-sectional area (mm ² ).

[resin]
The resin constituting the present invention is a semi-aromatic polyamide resin containing 1,9-nonanediamine units. The acid component is an aromatic dicarboxylic acid component and is preferably at least one selected from the group consisting of terephthalic acid and isophthalic acid. The diamine component contains a 1,9-nonanediamine unit, and preferably contains a 1,9-nonanediamine unit in an amount of 50 mol% or more of the repeating unit.
The semi-aromatic polyamide resin containing 1,9-nonanediamine unit is preferably kept in the resin bath container under the necessary heating conditions with a viscosity of 100 to 3000 Pa · s (Ns / m ² ). It is a thing.

[Preliminary tension]
The tension per 24,000 single filaments of carbon fibers when drawn into a semi-aromatic polyamide-based resin melt containing a 1,9-nonanediamine unit as a diamine component is preferably 3 to 20N. Furthermore, it is preferable that it is 5-10N. If the tension is less than 3N, the impregnation of the resin may be insufficient, and if it exceeds 20N, carbon fluff may be generated. The preliminary tension can be adjusted by applying a contact type or non-contact type brake to the rotating body.
Even when the preliminary tension is set low when an attempt is made to obtain a semi-aromatic polyamide-based resin-impregnated strand containing a 1,9-nonanediamine unit as a diamine component, it is sufficient to carry it by the method of the present invention. It is a great feature of the present invention to enable easy resin impregnation. (Preliminary tension of carbon fiber / viscosity η of thermoplastic resin) is preferably 0.02 or less.

[Take-up tension]
The take-up tension of the impregnated strand measured at a point before the take-up machine is preferably 50 to 500 N per 24,000 single filaments. When the take-up tension per 24,000 single filaments exceeds 500 N, the fluff may stand up or break. If the take-up tension is less than 250N, sufficient impregnation may not be realized. More preferably, the take-up tension is 100 to 400 N per 24,000 pieces.
The take-up tension can be appropriately adjusted according to the setting condition of the preliminary tension and the conveyance speed. The take-up tension can be increased by increasing the conveying speed. The take-up tension can be appropriately adjusted depending on the shape of the roller and the arrangement of the rollers.

[Conveying speed]
It is preferable that the conveying speed of the impregnated strand at the time of pultrusion molding is 1 m / min or more and 40 m / min or less. If the conveying speed is less than 1 m / min, it is not preferable from the productivity of the impregnated strand. If it exceeds 40 m / min, sufficient resin impregnation may not be achieved, and fluff of carbon fibers may occur. A preferable conveying speed of the impregnated strand is 3 m / min or more and 20 m / min or less.

[Slanting, Roller angle]
It is a feature of the method of the present invention that a plurality of opening rollers are alternately arranged obliquely in a zigzag direction. As an alternately oblique arrangement, preferably (1) a configuration in which a plurality of opening rollers are on the same plane parallel to the fiber bundle and are arranged obliquely to each other, and (2) a plurality of opening rollers in the fiber bundle Examples thereof include configurations that are respectively arranged on a vertical plane and arranged obliquely to each other, and combinations thereof.

  FIG. 1 shows an example of the arrangement of the opening rollers when the plurality of opening rollers (1) are on the same plane parallel to the traveling direction of the fiber bundle and are arranged obliquely to each other. FIG. 2 shows a schematic diagram of a fiber opening device using. In addition, in order to show an example of an oblique roller arrangement in an easy-to-understand manner, FIG. 2 is a schematic front view, but the opening roller (3) in the impregnation bath (4) is expressed in a perspective view.

  The arrangement example of the opening roller in the case where the plurality of opening rollers of (2) are respectively on the plane perpendicular to the traveling direction of the fiber bundle and are arranged obliquely to each other is shown in FIG. A schematic diagram of the used opening device is shown in FIG. In addition, in order to show an example of an oblique roller arrangement in an easy-to-understand manner, FIG. 4 is a schematic front view, but the opening roller (3) in FIG.

  The procedure for producing the spread pellets is as shown in FIG. 2 or FIG. The carbon fiber bundle 1 is introduced from the feed roller into the impregnation bath 4 through the yarn path guide 2. A semi-aromatic polyamide resin containing 1,9-nonanediamine units is introduced from the extruder 5 into the impregnation bath 4 and the impregnation bath is filled with a semi-aromatic polyamide resin containing 1,9-nonanediamine units in the molten state. . A plurality of opening rollers 3 are installed in the impregnation bath. A strand of carbon fiber impregnated with a thermoplastic resin in the take-up direction is conveyed and taken up by a take-up machine 7 through a cooling tank 6. Further, a pelletizer 8 is installed, and the impregnated strand can be cut to obtain carbon fiber reinforced thermoplastic resin pellets.

  In the case of (1), on the same plane parallel to the fiber bundle, the first roller is obliquely arranged at an angle of θ1 with respect to the fiber bundle running and the vertical direction with respect to the running direction of the fiber bundle, and the next roller is Specifically, a configuration in which the arrangement is repeatedly arranged at an angle of θ2 in the opposite direction so as to cancel the inclination angle θ1 is specifically mentioned. At this time, the absolute values of θ1 and θ2 may be the same or different, but for the purpose of suppressing meandering of the fiber bundle, the difference between the absolute values of θ1 and θ2 is 5 ° to 20 °. It is preferable that the absolute values coincide with each other. It is preferable that the inclination angle θ of the roller with respect to the direction perpendicular to the fiber bundle travel is 5 to 20 °, more preferably 10 to 15 ° in both the plus direction and the minus direction.

  In the case of (2), on the surface perpendicular to the traveling direction of the fiber bundle, the first roller is disposed obliquely at an angle of θ1 with respect to the traveling direction of the fiber bundle, and the next roller is disposed as described above. Specifically, a configuration in which the arrangement is repeatedly arranged so as to be obliquely arranged on a surface perpendicular to the traveling direction of the fiber bundle at an angle of θ2 in the opposite direction so as to cancel the inclination angle θ1 can be given. At this time, the absolute values of θ1 and θ2 may be the same or different, but for the purpose of suppressing meandering of the fiber bundle, the difference between the absolute values of θ1 and θ2 is 5 ° to 20 °. It is preferable that the absolute values coincide with each other. It is preferable that the inclination angle θ of the roller with respect to the direction perpendicular to the fiber bundle travel is 5 to 20 °, more preferably 10 to 15 ° in both the plus direction and the minus direction.

The total number of the opening rollers to be used is plural, but preferably 4 to 8, and may be an even number or an odd number.
Also, depending on the inclination angle and the like, the two rollers may approach each other and the rollers may not be arranged side by side, so they are appropriately arranged based on the diameter and length of the rollers.
The distance R between the rollers is the distance between the centers of the two rollers. The distance R between the rollers is preferably D / 10 <R <2 × D with respect to the width D of the fiber bundle before impregnation. When using a plurality of rollers, the distance between the rollers may be equal or different.

  It is preferable that the fiber bundles are passed through in zigzag form along rollers alternately arranged obliquely. By being conveyed in contact with the zigzag, the thermoplastic resin conveyed into the head is caught in the gap between the fiber bundle and the roller when the fiber bundle contacts the roller. Since the take-up tension acting on the fiber bundle is generated in the vertical component direction with respect to the roller, the entrained resin is impregnated into the fiber bundle by the tension in the vertical component direction of the take-up tension. As a result, a thermoplastic resin-impregnated strand of carbon fiber having a sufficiently opened fiber bundle and excellent resin impregnation property can be obtained.

[Long fiber pellet]
By cutting the impregnated strand obtained by the production method of the present invention, a long fiber pellet of a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component and carbon fiber can be obtained. Since it is possible to obtain an impregnated strand having a high resin content (low carbon fiber content) by the production method of the present invention, a long fiber pellet having a higher resin content (low carbon fiber content) is obtained. be able to. The carbon fiber content is preferably 10 to 50% by weight, more preferably 20 to 40% by weight.

Examples are shown below, but the present invention is not limited thereto. The physical properties of the pellet were determined as follows: (1) Fiber weight content: The pellet was dissolved in sulfuric acid and the resin component was removed to determine the change in weight.
(2) Impregnation rate: The obtained pellets were divided, and the carbon fibers not impregnated with the resin were further divided to determine the weight of the dry fibers, and the following formula (4) was obtained.
Impregnation rate (wt%) = 100-Wdf / (Wp x Wf) (4)
In this formula, Wdf is the dry fiber weight in the long fiber pellet, Wp is the long fiber pellet weight, and Wf is the fiber weight content.

[Example 1]
Carbon fiber filaments (STS40 manufactured by Toho Tenax Co., Ltd., average diameter 7 μm, number of filaments 24,000, tensile strength 4000 MPa, fiber bundle width 9 mm. Average diameter, number of filaments, and tensile strength are catalog values. 1) and 2), an impregnated strand was produced using an apparatus in which a plurality of opening rollers as shown in FIGS. 1 and 2 are arranged obliquely to each other on the same plane parallel to the traveling direction of the fiber bundle. As shown in FIG. 1, the roller angle is an inclination based on the direction perpendicular to the fiber bundle traveling, the first roller inclination being 15 °, the second roller inclination −15 °, and the third roller inclination 15 °. Four rollers were arranged obliquely so that the fourth roller inclination was −15 °, and all four rollers were equally spaced. The diameters of the opening rollers are all 6 mm.
Nylon 9T resin (manufactured by Kuraray Co., Ltd.) which is a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component having a shear viscosity of 500 Pa · s at a shear rate of 100 (1 / s) under the conditions described in Table 1. Pultruded together with a registered trademark Genesta N1000A M42 NATURAL) to obtain impregnated strands, which were cut into pellets. The impregnation rate of the obtained pellets was 95%.

[Examples 2 to 6]
In the same manner as in Example 1, impregnated strands were obtained under the conditions described in Table 1, and were cut to obtain pellets. Table 1 shows the impregnation rate of the obtained pellets. The roller angle of 10 ° means the first roller tilt of 10 °, the second roller tilt of −10 °, the third roller tilt of 10 °, and the fourth roller tilt of −10 °. .

[Example 7]
Except that the inclination angle of the roller was 25 °, an impregnated strand was obtained in the same manner as in Example 1. As a result, the fiber bundle meandering was large and stable production was difficult. Was written.

[Example 8]
Carbon fiber filaments (STS40 manufactured by Toho Tenax Co., Ltd., average diameter 7 μm, number of filaments 24,000, tensile strength 4000 MPa, fiber bundle width 9 mm. Average diameter, number of filaments, and tensile strength are catalog values. 3) and 4), an impregnated strand was produced using an apparatus in which a plurality of opening rollers as shown in FIGS. 3 and 4 are arranged obliquely on a plane perpendicular to the traveling direction of the fiber bundle. As shown in FIG. 3, the roller angle is an inclination based on the direction perpendicular to the fiber bundle traveling, the first roller inclination is 15 °, the second roller inclination is −15 °, and the third roller inclination is 15 °. Four rollers were arranged obliquely so that the fourth roller inclination was −15 °, and all four rollers were equally spaced. The diameters of the opening rollers are all 6 mm.
Under the conditions shown in Table 1, it was drawn together with nylon 9T resin (Kuraray Co., Ltd., registered trademark Genesta N1000A M42 NATURAL) having a shear viscosity of 500 Pa · s at a shear rate of 100 (1 / s) to obtain an impregnated strand. Then, it was cut to obtain a pellet. The impregnation rate of the pellets obtained in Example 8 was 99%.

[Examples 9 to 14]
In the same manner as in Example 8, impregnated strands were obtained under the conditions described in Table 1, and were cut to obtain pellets. Table 1 shows the impregnation rate of the obtained pellets. The roller angle of 10 ° means the first roller tilt of 10 °, the second roller tilt of −10 °, the third roller tilt of 10 °, and the fourth roller tilt of −10 °. . In Example 14, since the meandering of the fiber bundle was large and stable production was difficult, the values measured for some samples were shown.

[Comparative Example 1]
An impregnated strand was obtained in the same manner as in Example 1 except that the tilt angle of the roller was 0 °, that is, the rollers were arranged in a straight line, and was cut to obtain pellets. The production conditions and the obtained impregnation rate are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Carbon fiber bundle 2 Thread guide 3 Opening roller 4 Impregnation bath 5 Extruder 6 Cooling tank 7 Take-out machine 8 Pelletizer

Claims (8)

  A method for producing a strand in which a carbon fiber is impregnated with a semi-aromatic polyamide resin containing a 1,9-nonanediamine unit as a diamine component, wherein a plurality of opening rollers are alternately arranged obliquely with respect to the fiber bundle traveling A method for producing an impregnated strand of carbon fiber by filling a molten resin in a bath and impregnating the resin while allowing the carbon fiber bundle to pass through a fiber opening roller in the impregnation bath to open the fiber.   The method for producing an impregnated strand according to claim 1, wherein the plurality of opening rollers are arranged obliquely on the same plane parallel to the traveling direction of the fiber bundle.   The method for producing an impregnated strand according to claim 2, wherein the inclination angle θ of the opening roller with respect to the direction perpendicular to the fiber bundle traveling is 5 to 20 ° in both the plus direction and the minus direction.   The method for producing an impregnated strand according to claim 1, wherein the plurality of spread rollers are respectively provided on a plane perpendicular to the traveling direction of the fiber bundle and are arranged obliquely to each other.   The method for producing an impregnated strand according to claim 4, wherein an inclination angle θ of the opening roller with respect to the fiber bundle is 5 to 20 ° in both the plus direction and the minus direction.   The method for producing an impregnated strand according to any one of claims 1 to 5, wherein the distance R between the opening rollers is D / 10 <R <2xD with respect to the width D of the fiber bundle before impregnation.   The manufacturing method of the impregnation strand in any one of Claims 1-6 which run up and down so that a fiber bundle may follow the circular arc of a fiber opening roller.   Carbon fiber reinforced pellets comprising a semi-aromatic polyamide resin containing 1,9-nonanediamine units as a diamine component and carbon fibers, obtained by cutting the impregnated strand obtained by the method according to claim 1.

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