JP6477459B2 - Method for producing fiber reinforced thermoplastic resin - Google Patents

Description

  The present invention relates to a method for producing a fiber-reinforced thermoplastic resin.

  Fiber reinforced thermoplastic resins are known, and molded products from fiber reinforced thermoplastic resins are used in many fields such as automobile parts. The fiber reinforced thermoplastic resin is produced by various manufacturing methods. As an example, as described in Patent Document 1, the thermoplastic resin as the matrix resin and the reinforced fiber are simultaneously fed into a kneading extruder, and kneading extrusion. There is known a production method in which both are kneaded by rotation of a screw while being heated in the machine, and discharged after being kneaded and extruded from a kneading extruder as an extrudate (bulk) of discontinuous fibers. A desired part is manufactured by supplying and molding the fiber-reinforced thermoplastic resin after extrusion to a mold.

  Further, as a reinforcing fiber, carbon fiber, glass fiber, aramid fiber or the like is used, an opened reinforcing fiber is used, and a method and an apparatus for opening such a reinforcing fiber bundle are described in Patent Document 2. Yes.

WO2002 / 043686 Publication JP 2013-159876 A

  When producing a fiber reinforced thermoplastic resin using a kneading extruder, the dispersion state of the reinforced fiber in the fiber reinforced thermoplastic resin is improved by using the reinforced fiber opened as the reinforcing fiber mixed in the matrix resin. I can expect that. For this purpose, the inventors have wound the reinforcing fiber after the fiber opening treatment into a bobbin, and put the fiber reinforcing fiber unwound from the fiber into the matrix resin melted in the kneading extruder, A fiber reinforced thermoplastic resin was produced. However, when the reinforcing fibers after the fiber-opening treatment are wound around the bobbin, the ultrafine fibers are entrapped in the lower reinforcing fibers, or the ultrafine fibers are entangled between the upper and lower reinforcing fibers. For this reason, it has become difficult to smoothly and smoothly unwind the reinforcing fiber from the bobbin, and the reinforcing fiber has been unexpectedly cut. This could be observed although there was a difference in the degree even when the reinforcing fiber that was not opened was wound around the bobbin.

  The present invention has been made in view of the above circumstances, and in a method for producing a fiber-reinforced thermoplastic resin in which reinforcing fibers are kneaded in a matrix resin, which is a thermoplastic resin, using a kneading extruder, A method for producing a fiber reinforced thermoplastic resin in which the reinforced fibers entrained are smoothly and continuously supplied to a kneading extruder, thereby stably producing a fiber reinforced thermoplastic resin. It is an object to disclose.

  The method for producing a fiber-reinforced thermoplastic resin according to the present invention is a method for producing a fiber-reinforced thermoplastic resin in which reinforcing fibers are kneaded in a matrix resin that is a thermoplastic resin, and is the same as the thermoplastic resin that is the matrix resin. A step of preparing a laminate of a thermoplastic resin sheet made of a resin species and the reinforcing fiber, a step of winding the laminate into a bobbin, and unwinding the laminate from the bobbin to form the matrix resin in the kneading extruder And at least a step of mixing the matrix resin kneaded in the kneading extruder and a kneaded product of the laminate as a fiber-reinforced thermoplastic resin from the kneading extruder.

  According to this invention, the thermoplastic resin sheet which consists of the same resin seed | species as the thermoplastic resin which is matrix resin interposes between the upper and lower reinforcement fiber in the reinforcement fiber wound in the bobbin. For this reason, the upper and lower reinforcing fibers are not in direct contact with each other. Thereby, the ultrafine fibers are not sunk into the adjacent reinforcing fibers, and the ultrafine fibers are not entangled between the adjacent reinforcing fibers. As a result, unwinding of the reinforcing fiber from the bobbin proceeds smoothly and can be prevented from unexpectedly breaking. In addition, the intervening thermoplastic resin sheet is simultaneously supplied to the kneading extruder and mixed into the matrix resin, but the resin type is the same as the resin type of the thermoplastic resin that is the matrix resin, and the fiber-reinforced heat produced. It does not affect the physical properties of the plastic resin. Furthermore, since the reinforcing fibers and the thermoplastic resin sheet are supplied into the kneading extruder, the impregnation property of the resin into the reinforcing fibers in the kneading extruder is improved.

Schematic which shows an example of the molding machine provided with the kneading extruder suitable for implementing the manufacturing method of the fiber reinforced thermoplastic resin by this invention. The figure for demonstrating the aspect of the bobbin used with the manufacturing method of the fiber reinforced thermoplastic resin by this invention, and the laminated body unwound from there.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a molding machine equipped with a kneading extruder suitable for carrying out the method for producing a fiber-reinforced thermoplastic resin according to the present invention. In the following example, the reinforced fiber opened as the reinforced fiber is used. However, the present invention is similarly applied to a case where a reinforced fiber not opened is used.

  In this example, the molding machine 1 includes a multiaxial (or uniaxial) melt extruder 10 as a resin melting portion on the most upstream side. The melt extruder 10 has a hopper 11 into which a thermoplastic resin 12 that is a matrix resin and, if necessary, an additive 13 are charged. Examples of thermoplastic resin 12 include, but are not limited to, polyamide, polypropylene, polyethylene, polyetheretherketone, polyester, polystyrene, polycarbonate, polyvinyl chloride, polymethyl, polymethacrylate, acrylic, polyurethane, and mixtures thereof. . Examples of the additive 13 include, but are not limited to, an antioxidant, an ultraviolet absorber, and a flame retardant. The melt extruder 10 includes a heating device (not shown), and the thermoplastic resin 12 and the additive 13 are heated and melted by the heating device and sent to the outlet side.

  On the outlet side of the melt extruder 10, a multi-axis (or uniaxial) kneading extruder 20 that functions as a kneading extrusion section is located. The kneading extruder 20 is charged with a molten thermoplastic resin 2 extruded from the melt extrusion apparatus 10 as a matrix resin. The kneading extruder 20 is provided with an inlet 21 for the reinforcing fiber 4, from which the thermoplastic resin sheet 3 made of the same resin type as the thermoplastic resin 12 (preferably exactly the same resin) and the spread reinforcing fiber. The laminate 5 with 4 is charged. The kneading extruder 20 is also provided with an appropriate heating device or heat retention device (not shown).

  FIG. 2 shows an example of the laminate 5, and the laminate 5 of the thermoplastic resin sheet 3 and the spread reinforcing fibers 4 is wound around the bobbin 6. The thermoplastic resin sheet 3 is a sheet made of the same resin as the thermoplastic resin 12 which is a matrix resin, and can be manufactured by a normal method. The spread reinforcing fiber 4 is obtained by opening a bundle of reinforcing fibers by a normal method. For example, the reinforcing fiber 4 is manufactured by aligning a bundle of a predetermined number of reinforcing fibers in one direction and opening it into a sheet. can do. Alternatively, as described in Patent Document 1, fibers are opened while being moved in the width direction while bending the fibers by passing a fluid through the fiber bundle conveyed in the fiber length direction, and the fibers conveyed Rotate in a direction inclined with respect to the conveying direction while bringing the contact member into contact with the bundle to push a part of the fiber bundle into a tension state, and then separate the contact member from the fiber bundle in the tension state to separate the fiber bundle. It can also be manufactured by a manufacturing method that temporarily makes it relaxed. Although it does not limit as a reinforced fiber used as a foundation, For example, reinforced fibers, such as carbon fiber, glass fiber, and an aramid fiber, can be raised.

  The opened reinforcing fiber 4 and the separately produced thermoplastic resin sheet 3 are laminated by an appropriate method to form a laminate 5, which is wound around a bobbin 6. Alternatively, a film made of the same resin type as the matrix resin of the fiber reinforced thermoplastic resin to be manufactured is used as a base film when the fiber reinforced fibers 4 are manufactured, and the film is directly wound around the bobbin 6. Good.

  The laminate 5 is unwound from one or a plurality of bobbins 6 in which the laminate 5 thus prepared is wound, and the unrolled laminate 5 is fed from the inlet 21 of the kneading extruder 20 to the kneading extruder 20. In. The melted thermoplastic resin 2 is fed into the kneading extruder 20 so as to be extruded by a screw, and the loaded laminate 5 is mixed into the melted thermoplastic resin 2 and kneaded. And sent out toward the exit.

  As described above, in the laminate 5 wound around the bobbin 6, the thermoplastic resin sheet 3 is interposed between the upper and lower opening reinforcing fibers 4 and 4, and the upper and lower opening reinforcing fibers are located. The fibers 4 and 4 are not in direct contact. Therefore, unwinding of the laminate 5 from the bobbin 6 is performed smoothly, and the laminate 5 does not break unexpectedly on the way. The thermoplastic resin sheet 3 is the same resin (or resin type) as the thermoplastic resin 12 that is a matrix resin, and even if melted in the thermoplastic resin 12, it affects the physical properties of the fiber-reinforced thermoplastic resin produced. Never give. Furthermore, since the spread reinforcing fiber 4 and the thermoplastic resin sheet 3 are fed into the kneading extruder 20 in contact with each other, the impregnation property of the resin into the spread reinforcing fiber 4 in the kneading extruder 20 is also improved. .

  In the laminate 5, even if a release paper is used instead of the thermoplastic resin sheet 3, it is possible to avoid the fiber-reinforced reinforcing fibers 4, 4 positioned above and below from coming into direct contact. However, the release paper is a foreign matter for the fiber reinforced thermoplastic resin, and it is necessary to remove it in advance when supplying it into the kneading extruder 20, which makes the process complicated and the foreign matter is heated. There is also a possibility of mixing into the plastic resin 2, which is not preferable.

  In the laminate 5, the thermoplastic resin sheet 3 is extremely thin (for example, a thickness of about several tens μm) so as not to significantly affect the volume fraction of the spread reinforcing fiber in the kneaded product. Or the amount of the thermoplastic resin for the matrix to be charged in advance, and the amount of the thermoplastic resin sheet 3 is added, so that the desired resin amount in the fiber reinforced thermoplastic resin It may be made to become. By selecting one of them, a desired fiber-reinforced thermoplastic resin can be obtained.

  The kneaded product of the thermoplastic resin 12 and the laminate 5 kneaded in the kneading extruder 20 as described above is taken out from the kneading extruder 20 as the fiber reinforced thermoplastic resin 7. In the molding machine 1 shown in FIG. 1, the fiber reinforced thermoplastic resin 7 extruded from a die (not shown) of the kneading extruder 20 is cut into an appropriate size by a trimmer 8, and a conveying device 30 having a heat retaining function. Is sent to a molding press 40 having a fixed lower die 41 and a movable upper die 42, where it is molded into a desired product.

  As described above, by adopting the method for producing a fiber-reinforced thermoplastic resin according to the present invention, it becomes possible to smoothly and continuously supply the fiber-reinforced thermoplastic fibers wound in the bobbin toward the kneading extruder. Thus, the fiber-reinforced thermoplastic resin can be continuously produced stably. Moreover, since the impregnation property of the resin into the spread fiber is improved, the quality of the fiber reinforced thermoplastic resin is also improved.

  In the above description, the thermoplastic resin 2 melted by the melt extruder 10 is supplied to the kneading extruder 20 as a matrix resin, but the kneading extruder 20 has a required length and is upstream. The melt extruder 10 can be omitted as long as the thermoplastic resin charged in the can is melted in the kneading extruder. Moreover, the conveying apparatus 30 and the molding press 40 are one example when using the fiber reinforced thermoplastic resin 7 manufactured with the manufacturing method of the fiber reinforced thermoplastic resin by this invention, Comprising: It can change into another thing. It is.

1 ... Molding machine,
2 ... Molten thermoplastic resin,
3 ... thermoplastic resin sheet,
4 ... spread fiber,
5 ... Laminate,
6 ... bobbins,
7: Fiber reinforced thermoplastic resin,
10: Melt extruder,
20 ... kneading extruder,
30 ... Conveying device,
40 ... Molding press.

Claims (1)

A method for producing a fiber-reinforced thermoplastic resin in which reinforcing fibers are kneaded in a matrix resin that is a thermoplastic resin,
A step of preparing a laminate of a thermoplastic resin sheet made of the same resin species as the thermoplastic resin as the matrix resin and the reinforcing fibers;
Winding the laminate around a bobbin;
Unwinding the laminate from the bobbin and mixing it into the matrix resin in a kneading extruder;
Removing the kneaded product of the matrix resin and the laminate kneaded in the kneading extruder from the kneading extruder as a fiber reinforced thermoplastic resin;
A method for producing a fiber-reinforced thermoplastic resin, characterized by comprising:

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