JP4467326B2 - Production method - Google Patents

Description

  The present invention relates to a method for producing a fiber-reinforced thermoplastic resin composition obtained by melt-kneading continuous reinforcing fibers with a twin-screw extruder. More specifically, the present invention relates to a method for producing a fiber-reinforced thermoplastic resin composition excellent in productivity and excellent in strength / rigidity and impact strength at high temperatures and the composition.

Fiber reinforced thermoplastic resins are used in various industrial fields by taking advantage of their excellent mechanical properties. In general, a fiber-reinforced thermoplastic resin is produced by kneading a thermoplastic resin and short fibers such as chopped strands with an extruder. However, this method has a problem that it is impossible to meet demands for high mechanical properties because fiber breakage cannot be avoided during kneading in an extruder.
On the other hand, in recent years, it has been studied to lengthen the reinforcing fibers as a method for fully extracting the performance inherent in the fibrous reinforcing material to be blended. As such a long fiber reinforced thermoplastic resin, for example, it is obtained by a pultrusion method in which a resin is impregnated while drawing a strand from a continuous roving of reinforcing fibers, compared with the short fiber reinforced thermoplastic resin. It has excellent strength / rigidity and impact strength at high temperatures (for example, see Patent Document 1).

However, in such a pultrusion method, a continuous reinforcing fiber strand is drawn and pelletized while impregnating the resin, so the fiber length in the pellet is long, but the productivity is poor and the resin is not low viscosity. In addition to the disadvantage that the reinforcing fibers cannot be sufficiently impregnated, there is a problem that the fibers are not uniformly dispersed in the molded product.
In addition, by controlling the degree of opening and uniformly dispersing reinforcing fibers, while maintaining a long weight average fiber length, a specific fiber length distribution is obtained by kneading action, thereby improving productivity, fluidity, and mechanical properties. It has been proposed to improve the surface smoothness and the like. However, this method has a problem that it is difficult to manufacture with an ordinary extruder because special processing is required for a part of the inner wall of the screw and / or cylinder of the extruder (see, for example, Patent Document 2). ).
Japanese Patent Publication No.52-3985 Japanese Patent Application Laid-Open No. 07-80834

  An object of this invention is to provide the manufacturing method of the fiber reinforced thermoplastic resin composition which was excellent in productivity, and was excellent in the intensity | strength and rigidity at high temperature, and impact strength.

  As a result of intensive studies in order to solve the above problems, the present inventor is a method for producing a thermoplastic resin composition produced by melt-kneading a reinforcing fiber continuous with a thermoplastic resin with a twin-screw extruder. By controlling the reinforcing fiber length in the composition, it is possible to obtain a fiber-reinforced thermoplastic resin composition excellent in strength, rigidity and impact strength at high temperatures with excellent productivity. The headline and the present invention have been completed.

That is, the present invention
1 . A method for producing a fiber-reinforced thermoplastic resin composition produced by melt-kneading a thermoplastic resin and continuous reinforcing fibers with a twin-screw extruder, which is continuous downstream of the reinforcing fiber supply position Using a twin-screw extruder having a part (A) for cutting the reinforcing fiber and controlling the reinforcing fiber length and a part (B) for dispersing the reinforcing fiber cut downstream of the part (A) When the reinforcing fiber is supplied from the position where the thermoplastic resin in the machine is in a molten state, and the continuous reinforcing fiber is defined as 0 for the most upstream barrel length of the twin screw extruder and 1 for the most downstream barrel, A method for producing a fiber-reinforced thermoplastic resin composition, characterized by cutting at (A) part provided at a position of 0.75 to 0.98, and dispersing the cut reinforcing fiber at (B) part,

2 . The reinforcing fiber supply position is set to 0 . The method for producing a fiber-reinforced thermoplastic resin composition according to the above 1, wherein the fiber-reinforced thermoplastic resin composition is provided at a position of 50 or more,
3 . (A) The part is composed of parts having a shape having a blade for cutting the reinforcing fiber in the same direction as the screw axial direction, and the (B) part is a screw part having a shape having a notch on the screw flight. A method for producing a fiber-reinforced thermoplastic resin composition as described in 1 or 2 above,

4. (A) The ratio (La / Da) of the block length La of the parts constituting the part to the screw diameter Da of the extruder is 0.3 to 1.5, and the block length Lb of the screw parts constituting the part (B) and the extrusion. The ratio of screw diameter Db of the machine (Lb / Db) is 0.3 to 4.0, the method for producing a fiber-reinforced thermoplastic resin composition according to any one of the above 3 ,
5 . The method for producing a fiber-reinforced thermoplastic resin composition according to any one of the above 1 to 4 , wherein 10 to 170 parts by weight of continuous reinforcing fibers are added to 100 parts by weight of the thermoplastic resin,
6 . The method for producing a fiber-reinforced thermoplastic resin composition according to any one of the above 1 to 5 , wherein the thermoplastic resin is a polyamide resin, and the reinforcing fibers are glass fibers,
It is.

  According to the present invention, a fiber reinforced thermoplastic resin composition with a controlled reinforcing fiber length can be obtained by melt-kneading a strand or roving composed of reinforcing fibers continuous with a thermoplastic resin by a twin screw extruder. . Therefore, it is suitably used for automobile parts and the like that require strength / rigidity and impact strength at high temperatures.

The present invention is described in detail below.
In the twin-screw extruder used in the present invention, the ratio of the total barrel length L to the barrel diameter D is (L / D) 30 or more and 120 or less, from the viewpoint that the thermoplastic resin is in a molten state and supplies reinforcing fibers. A screw extruder is preferable, and a twin screw extruder of 30 to 70 is more preferable.
There are no particular restrictions on the method that can achieve the molten state of the thermoplastic resin, but within the range that does not affect the deterioration of the thermoplastic resin, a method of increasing the heater temperature upstream of the reinforcing fiber supply position, or a kneading block A method of increasing the melting temperature by generating shear heat can be exemplified.
The continuous reinforcing fiber used in the present invention is not particularly limited as long as it is a strand or roving obtained by bundling continuous single fibers, but a coupling agent or the like is used to improve the adhesion between the reinforcing fiber and the resin interface. It is preferable that surface treatment is performed. The reinforcing fiber is not particularly limited as long as it is usually used for reinforcing a resin, and glass fiber, carbon fiber, metal fiber, organic fiber, etc. can be used. Used most widely.

  The glass fiber for polyamide resin preferably used in the present invention has a surface with a sizing agent for polyamide resin (this includes a sizing component for the purpose of sizing and a surface treatment component for the purpose of adhesion between the polyamide resin). What is being processed can be used. The constituents of the sizing agent are not particularly limited, but those containing a copolymer of maleic anhydride and an unsaturated monomer and an amino group-containing silane coupling agent as the main constituents can improve the mechanical properties. Most preferable from the viewpoint.

  Specific examples of the copolymer of maleic anhydride and unsaturated monomer constituting the sizing agent include styrene, α-methylstyrene, butadiene, isoprene, chloroprene, 2,3-dichlorobutadiene, and 1,3-pentadiene. And a copolymer of an unsaturated monomer such as cyclooctadiene and maleic anhydride. Among them, a copolymer of butadiene, styrene and maleic anhydride is particularly preferable. Further, these monomers may be used in combination of two or more, for example, by using a blend such as a mixture of maleic anhydride and a butadiene copolymer and a maleic anhydride and a styrene copolymer. It doesn't matter. The copolymer of maleic anhydride and unsaturated monomer preferably has an average molecular weight of 2,000 or more. Further, the ratio of maleic anhydride and unsaturated monomer is not particularly limited. Furthermore, in addition to the maleic anhydride copolymer, an acrylic acid copolymer or a urethane polymer may be used in combination.

  As the silane coupling agent which is another component constituting the sizing agent, any silane coupling agent which is usually used for the surface treatment of glass fibers can be used. Specifically, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) aminopropyltrimethoxysilane, N -Aminosilane coupling agents such as β (aminoethyl) aminopropyltriethoxysilane; γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, etc. Epoxy silane coupling agents; methacryloxy silanes such as γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane Mosquito Coupling agent; vinyltrimethoxysilane, vinyltriethoxysilane, and the like vinyltris (beta-methoxyethoxy) vinylsilane coupling agents such as silane. Two or more of these coupling agents can be used in combination.

Of these, aminosilane coupling agents are most preferred because of their affinity for polyamide resin, and among them, γ-aminopropyltriethoxysilane and N-β (aminoethyl) γ-aminopropyltriethoxysilane are most preferred. The proportion of the maleic anhydride copolymer and the silane coupling agent used is preferably the proportion of 0.01 to 20 parts by weight of the latter with respect to 100 parts by weight of the former that gives a relatively good balance of physical properties. Normally, maleic anhydride copolymer and silane coupling agent are mixed in an aqueous solvent and used as a sizing agent. If necessary, surfactants, lubricants, softeners, antistatic agents, etc. may be added. Also good.
Further, the average fiber diameter of the reinforcing fibers is not particularly limited, and is preferably 5 μm or more from the viewpoint of convergence, preferably 20 μm or less from the viewpoint of improvement of mechanical properties, and further the average fiber diameter of 8 to 17 μm is the composition. It is preferable from the viewpoint of improving mechanical properties. The number of reinforcing fibers bundled is not particularly limited, but a strand or roving obtained by bundling 1,000 to 10,000 fiber monofilaments is preferable from the viewpoint of handling.

The continuous reinforcing fiber supply position of the present invention needs to be supplied from a supply port provided at a position where the thermoplastic resin is in a molten state from the viewpoint of preventing breakage of the reinforcing fiber and obtaining good mechanical properties. Yes, if the thermoplastic resin is in a molten state, the supply position is not limited, but it is preferable to supply from a downstream position including 0.50 of the total length of the barrel (the most upstream is defined as 0 and the most downstream is defined as 1). .)
The method of supplying continuous reinforcing fibers according to the present invention is specifically a method in which continuous reinforcing fiber strands or rovings are wound into an extruder by rotating an extruder screw, and are stably supplied into the extruder for a long time. From the viewpoint of achieving this, it is preferable to supply the extruder through a reinforcing fiber supply pipe. The reinforcing fiber supply pipe is intended to prevent the roving of a plurality of reinforcing fibers from being entangled before supplying the reinforcing fibers into the extruder, and the material of the pipe is not particularly limited.

In the screw configuration of the extruder of the present invention, from the viewpoint of controlling the fiber length of continuous reinforcing fibers and uniformly dispersing in the resin composition to obtain good mechanical properties, the downstream side from the reinforcing fiber supply position. (A) a continuous reinforcing fiber is cut and the reinforcing fiber length is controlled (A) part, and (B) the (B) part is dispersed in the downstream of the (A) part. It is necessary to provide it.
Here, part (A) is made up of parts with a shape that has a blade for cutting reinforcing fibers in the same direction as the axial direction of the screw. Specifically, the part (A) is wound in an extruder and moves forward while being wound around the screw. The continuous reinforcing fibers are cut by reinforcing the parts constituting the part (A) so that the reinforcing fibers are cut and the fiber length in the composition is controlled. Here, the fiber length of the reinforcing fiber cut by the part (A) is determined by the number of blades of the part (A), the distance between the blades, the number of parts, etc., but the weight average fiber length is 10 mm to 300 mm. It is preferable to configure the part (A) so that

  Further, the screw parts constituting the part (B) are specifically characterized by a shape having a notch on the screw flight, and the reinforcing fibers cut at the part (A) are dispersed in the resin. The screw element may be a forward screw type, a reverse screw type, or a combination thereof depending on the type and concentration of the reinforcing fiber. In addition, the parts which comprise this (A) and (B) part can use a commercially available part. Examples of commercially available parts in part (A) include MIXING SCREW ELEMENT HME manufactured by WERNER & PFLIDELER, and examples of commercially available parts in part (B) include SCREW ELEMENT ZME and SCREW ELEMENT SME manufactured by WERNER & PFLIDELER.

The ratio (La / Da) of the block length La of the part constituting the part (A) to the screw diameter Da of the extruder and the ratio of the block length Lb of the screw part constituting the part (B) to the screw diameter Db of the extruder ( Lb / Db) controls the fiber length of continuous reinforcing fibers and uniformly disperses them in the resin composition, and at the same time, prevents (La / Da) from being 0 0.3 to 1.5, (Lb / Db) is preferably 0.3 to 4.0, (La / Da) is 0.3 to 1.0, and (Lb / Db) is 0.3 to 2.0. Is more preferable. Here, the block length means the total part length.
The (A) part is 0.75 of the total length of the extruder from the viewpoint that the cut reinforcing fiber minimizes breakage downstream from the (A) part and the (B) part is arranged downstream from the (A) part. It is preferable to arrange at ˜0.98, more preferably at 0.80 to 0.98. Here, the breakage of the reinforcing fiber downstream from the part (A) is, for example, a breakage caused by rubbing between insufficiently dispersed reinforcing fibers between the screw of the extruder and the inner wall of the cylinder of the extruder, Possible cause is breakage due to contact.

When the parts (A) and (B) are composed of a plurality of parts, the parts may be provided continuously or intermittently as long as the above conditions are satisfied.
The screw configuration other than the parts (A) and (B) on the downstream side of the reinforcing fiber supply position is not particularly limited. However, the thermoplastic resin, the water vapor vaporized by the supply of the reinforcing fiber, the entrained air In order to prevent deterioration in quality due to volatile components of residual monomers and additives, it is preferable to provide a vent port downstream from the reinforcing fiber supply position and remove the generated gas component under reduced pressure. When removing under reduced pressure, it is preferable to provide a kneading disk or the like between the reinforcing fiber supply position and the part A) and seal it. However, an excessive shearing force is applied to the reinforcing fiber, which causes breakage of the reinforcing fiber. It is necessary to take care not to become excessive. The screw structure upstream of the reinforcing fiber supply position is not particularly limited as long as a sufficient shearing force is applied to plasticize the thermoplastic resin, but usually one or more upstream from the reinforcing fiber supply position. A method of providing a reverse screw screw is preferable.

  Examples of the thermoplastic resin according to the present invention include polyamide resin, polyolefin resin, polyester resin, polycarbonate resin, acrylic resin, polysulfone resin, polyphenylene ether resin, polyurethane resin, polyether resin, polyacetal resin, and the like. A combination of the above thermoplastic resins may also be used. In addition, an antioxidant, an ultraviolet absorber, a heat stabilizer, a photodegradation inhibitor, a plasticizer, a lubricant, a mold release agent, which are added to a normal thermoplastic resin as necessary within the range not impairing the object of the present invention. Agents, nucleating agents, flame retardants, color pigments, dyes, and the like can also be added.

  As the thermoplastic resin, polyamide resin is most widely used from the viewpoint of excellent strength and rigidity at high temperatures. Specific examples of the polyamide resin include, for example, nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 11, nylon 12, nylon MXD6, nylon obtained by polymerizing hexamethylenediamine and isophthalic acid (nylon 6I). , Homopolymers such as nylon (nylon PACMI) obtained by polymerizing isophthalic acid and bis (3-methyl-4-aminocyclohexyl) methane, nylons obtained by polymerizing adipic acid, isophthalic acid and hexamethylenediamine (nylon 66) Nylon (Nylon 66 / 6I / 6 copolymer) obtained by polymerizing adipic acid, isophthalic acid, hexamethylenediamine, and ε-caprolactam, polymerizing adipic acid, terephthalic acid, and hexamethylenediamine. Nylon (Nairo 66 / 6T copolymer).

  Further, nylon (nylon 6I / 6T copolymer) obtained by polymerizing isophthalic acid, terephthalic acid and hexamethylenediamine, terephthalic acid, 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylene Nylon obtained by polymerizing diamine (nylon TMDT copolymer), copolymer nylon obtained by polymerizing isophthalic acid, terephthalic acid, hexamethylenediamine and bis (3-methyl-4-aminocyclohexyl) methane, and isophthalic acid Examples include a mixture of copolymerized nylon and nylon 6 obtained by polymerizing terephthalic acid, hexamethylenediamine and bis (3-methyl-4-aminocyclohexyl) methane, and a mixture of MXD6 nylon and nylon 66.

The compounding amount of the reinforcing fiber in the fiber reinforced thermoplastic resin composition of the present invention is 10 parts by weight or more from the viewpoint of mechanical properties and 170 weights from the viewpoint of fiber breakage, etc. with respect to 100 parts by weight of the thermoplastic resin. Part or less is preferable, and 20 to 150 parts by weight is more preferable.
The glass fiber reinforced polyamide resin composition of the present invention can be used in known molding processes such as injection molding, extrusion molding, blow molding, and press molding. In a screw type molding machine usually used for injection molding or extrusion molding, it is preferable from the viewpoint of mechanical properties that a nozzle or gate shape is enlarged and a deep groove molding machine screw is used in order to suppress breakage of reinforcing fibers.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the raw material and the measuring method which were used for the Example and the comparative example are shown below.
<Raw materials>
[1] Polyamide resin PA-1: Polyamide 66, Leona 1300-001 manufactured by Asahi Kasei Chemicals Corporation
[2] Glass fiber ・ GF-1: manufactured by Nippon Electric Glass Co., Ltd., glass fiber bundle (roving), glass fiber average diameter 13 μm, number of fiber monofilaments per roving 4000, main component of sizing agent [styrene-anhydrous malein Acid copolymer, γ-aminopropyltriethoxysilane]
GF-2: manufactured by Nippon Electric Glass Co., Ltd., glass fiber bundle (roving), glass fiber average diameter 17 μm, 4000 fiber monofilaments per roving, main component of sizing agent [styrene-maleic anhydride copolymer, γ-aminopropyltriethoxysilane]
GF-3: manufactured by Nippon Electric Glass Co., Ltd., chopped strand, glass fiber average diameter 13 μm, glass fiber average length 3 mm, sizing agent main component [styrene-maleic anhydride copolymer, γ-aminopropyltriethoxysilane ]
<Creation of specimen>
Using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd .: FN3000), a multi-purpose test piece A type conforming to ISO 3167 was molded at a mold temperature of 80 ° C., and a test piece for bending test, Charpy impact strength test The test piece was cut.

[Measuring method]
(1) Flexural modulus, flexural strength According to ISO 178, the test piece was an autograph (manufactured by Shimadzu Corporation: AG-5000D type), crosshead speed 5 mm / min, span 64 mm, ambient temperature 23 ° C. The measurement was performed at 150 ° C.
(2) Charpy impact strength According to ISO 179, the test piece with a notch was subjected to an ambient temperature of 23 ° C. using a Charpy impact strength test device (Toyo Seiki Seisakusho: DG-C (A, B) Charpy method). The measurement was performed under the condition of -30 ° C.
(3) Weight average length of glass fiber 1 g or more of a glass fiber reinforced polyamide resin composition was burned only in a 650 ° C. electric furnace, then observed under an optical microscope, and randomly using an image analyzer. The weight average length of the glass fibers was determined from the value obtained by measuring the length of 400 glass fibers selected in the above.

[Example 1]
As the extruder, a twin screw extruder ZSK40MC (manufactured by WERNER & PFLIDEERER) (L / D = 48) was used. Polyamide resin PA-1 is supplied at 40 kg / hr using a constant-weight feeder from the most upstream supply port, and continuous glass fiber GF-1 having a roving number of 5 is fed through the glass fiber supply pipe to a total length of 0. From the position 82 (when the most upstream is 0 and the most downstream is 1), it is fed into a polyamide resin melted at 20 kg / hr, and the strand extruded from the nozzle is cooled, and then has a length of 8 mm and a diameter of 4 mm. The glass fiber-reinforced polyamide resin composition having a glass fiber concentration of 33% by weight was obtained by cutting into pellets and drying. The barrel temperature of the extruder is 285 ° C., the screw rotation speed is 500 rpm, and the discharge rate of the glass fiber reinforced polyamide resin composition is 60 kg / hr. In addition, the screw configuration is as follows: (A) part at 0.93 position of the total length of the extruder, MIXING SCREW ELEMENT HME as (B) section at 0.96 position of the total length of the extruder, and SCREW ELEMENT ZME and SCREW ELEMENT A combination of SMEs was used. At this time, La / Da = 0.45, and Lb / Db = 1.13. The obtained resin composition was molded by the above-described method at a cylinder temperature of 290 ° C., and various properties were evaluated. The results are shown in Table 1. Compared to Comparative Example 1, it is excellent in strength, rigidity and impact strength at high temperatures.

[Example 2]
The glass fiber concentration was 33% by weight in the same manner as in Example 1 except that the supply amount of the polyamide resin PA-1 was 66 kg / hr, the continuous glass fiber was GF-2, and the supply amount was 33 kg / hr. A glass fiber reinforced polyamide resin composition was obtained at a discharge rate of 99 kg / hr, and various properties were evaluated. The results are shown in Table 1. Compared to Comparative Example 1, it is excellent in strength, rigidity and impact strength at high temperatures.

[Example 3]
The glass fiber concentration was adjusted in the same manner as in Example 1 except that the supply amount of the polyamide resin PA-1 was 46 kg / hr, the roving number of continuous glass fibers GF-2 was 7 and the supply amount was 46 kg / hr. A 50% by weight glass fiber reinforced polyamide resin composition was obtained at a discharge rate of 60 kg / hr, and various properties were evaluated. The results are shown in Table 2. Compared to Comparative Example 3, it is excellent in strength, rigidity and impact strength at high temperatures.

[Comparative Example 1]
As the extruder, a twin screw extruder TEM35BS (manufactured by Toshiba Machine Co., Ltd.) (L / D = 47) was used. Polyamide resin PA-1 is supplied at 34 kg / hr from the most upstream supply port using a constant-weight feeder, and the glass fiber GF-3 is 0.60 in the length of the extruder (the most upstream is 0 and the most downstream is 1). Then, side feed was carried out into a polyamide resin melted at 17 kg / hr using a constant-weight feeder. The strand extruded from the spinneret was cooled, then cut into pellets having a length of 3 mm and a diameter of 2 mm and dried to obtain a glass fiber reinforced polyamide resin composition having a glass fiber concentration of 33% by weight. The barrel temperature of the extruder is 285 ° C., the screw rotation speed is 300 rpm, and the discharge amount of the glass fiber reinforced polyamide resin composition is 51 kg / hr. Further, the screw configuration is provided with a reverse screw of L / D = 0.80 upstream from the glass fiber supply position for plasticizing the polyamide resin, and L / D downstream from the glass fiber supply position for glass fiber dispersion. Except for providing one reverse screw with D = 0.80, it was composed of only forward screws. The obtained resin composition was molded under the conditions of a cylinder temperature of 290 ° C. by the method described above and evaluated. The results are shown in Table 1. Compared to Example 1, since the weight average length of the glass fiber in the obtained resin composition is short, the strength / rigidity and impact strength at high temperature are inferior.

[Comparative Example 2]
By using a polyamide resin PA-1 and continuous glass fiber GF-1 having two rovings and passing through a polyamide resin coating die at 295 ° C., a pultrusion method is used to form a pellet having a length of 8 mm and a diameter of 3 mm. A glass fiber reinforced polyamide resin composition having a glass fiber concentration of 60% by weight was obtained. The production amount was 10 kg / hr. The obtained resin composition was diluted with polyamide resin pellets PA-1 so as to have the composition shown in Table 1, and then molded under the conditions of a cylinder temperature of 290 ° C. by the above-described method, and various properties were evaluated. The results are shown in Table 1. Compared with Examples 1 and 2, the mechanical properties are comparable, but the productivity by this production method is remarkably low.

[Comparative Example 3]
As in Example 1, as the extruder, a twin-screw extruder ZSK40MC (manufactured by WERNER & PFLEIDERER) (L / D = 48) was used. Polyamide resin PA-1 is supplied at 40 kg / hr from the most upstream supply port using a constant-weight feeder, and continuous glass fiber GF-2 having 20 rovings is fed through the glass fiber supply pipe to a total length of 0. From the position of 60 (when the most upstream is 0 and the most downstream is 1), it is fed into a polyamide resin melted at 40 kg / hr, and the strand extruded from the spout is cooled, and then has a length of 8 mm and a diameter of 4 mm. It was cut into pellets and dried to obtain a glass fiber reinforced polyamide resin composition having a glass fiber concentration of 50% by weight. The barrel temperature of the extruder is 285 ° C., the screw rotation speed is 150 rpm, and the discharge rate of the glass fiber reinforced polyamide resin composition is 80 kg / hr. Moreover, the screw structure provided the MIXING SCREW ELEMENT HME part which is La / Da = 0.45 as a (A) part in the position of 0.75 of the extruder full length. The obtained resin composition was molded by the above-described method at a cylinder temperature of 290 ° C., and various properties were evaluated. The results are shown in Table 2. Compared to Example 3, since the dispersibility of the glass fiber in the resin is inferior, the fiber length due to breakage caused by rubbing between insufficiently dispersed reinforcing fibers between the screw of the extruder and the inner wall of the cylinder of the extruder Becomes short and inferior in strength, rigidity and impact strength at high temperature.

[Comparative Example 4]
Compared to Example 3, a glass fiber reinforced polyamide resin composition having a glass fiber concentration of 50% by weight was produced in the same manner as in Example 3 except that the (B) part was not provided in the screw configuration. The obtained resin composition was tried to be molded under the condition of the cylinder temperature of 290 ° C. by the above-mentioned method. However, since the dispersion of the glass fiber was insufficient, the obtained glass fiber reinforced polyamide resin composition pellets were In addition, it was not possible to plasticize with a molding machine, and various properties could not be evaluated.

It is a figure which shows the outline | summary of the melt-kneading by the twin-screw extruder of the reinforced fiber continuous with the polyamide resin in an Example. It is a figure which shows the outline | summary of the melt-kneading by the twin-screw extruder of the reinforced fiber continuous with the polyamide resin in the comparative example 3.

  The molded article of the fiber reinforced thermoplastic resin composition obtained by the production method of the present invention can obtain a fiber reinforced thermoplastic resin composition excellent in strength, rigidity and impact strength at high temperatures with excellent productivity. Cylinder head cover, radiator tank, tire pressure sensor, car heater tank, water valve, radiator pipe, intake manifold, throttle body, engine mount, steering lock, front end module, door module, mirror bracket, pedal, bumper, wheel cap It can be suitably used for automobile parts such as under covers, outdoor fans, impellers such as cold water towers, electric tools, fishing tackle reels, breakers, and gears.

Claims (6)

A method for producing a fiber-reinforced thermoplastic resin composition produced by melt-kneading a thermoplastic resin and continuous reinforcing fibers with a twin-screw extruder, which is continuous downstream of the reinforcing fiber supply position Using a twin-screw extruder having a part (A) for cutting the reinforcing fiber and controlling the reinforcing fiber length and a part (B) for dispersing the reinforcing fiber cut downstream of the part (A) When the reinforcing fiber is supplied from the position where the thermoplastic resin in the machine is in a molten state, and the continuous reinforcing fiber is defined as 0 for the most upstream barrel length of the twin screw extruder and 1 for the most downstream barrel, A method for producing a fiber-reinforced thermoplastic resin composition, comprising cutting at (A) part provided at a position of 0.75 to 0.98 and dispersing the cut reinforcing fiber at (B) part. The reinforcing fiber supply position is set to 0 . The method for producing a fiber-reinforced thermoplastic resin composition according to claim 1, wherein the fiber-reinforced thermoplastic resin composition is provided at 50 or more positions. (A) The part is composed of parts having a shape having a blade for cutting the reinforcing fiber in the same direction as the screw axial direction, and the (B) part is a screw part having a shape having a notch on the screw flight. The manufacturing method of the fiber reinforced thermoplastic resin composition of Claim 1 or 2 characterized by these. (A) The ratio (La / Da) of the block length La of the parts constituting the part to the screw diameter Da of the extruder is 0.3 to 1.5, and the block length Lb of the screw parts constituting the part (B) and the extrusion. The ratio (Lb / Db) of screw diameter Db of a machine is 0.3-4.0, The manufacturing method of the fiber reinforced thermoplastic resin composition of any one of Claim 3 characterized by the above-mentioned. The method for producing a fiber-reinforced thermoplastic resin composition according to any one of claims 1 to 4 , wherein 10 to 170 parts by weight of continuous reinforcing fibers are added to 100 parts by weight of the thermoplastic resin. . The method for producing a fiber-reinforced thermoplastic resin composition according to any one of claims 1 to 5 , wherein the thermoplastic resin is a polyamide resin, and the reinforcing fibers are glass fibers.

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