JPH0825200B2 - FRTP continuous prepreg manufacturing method and manufacturing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to FRTP (Fiber Retainer) using continuous fibers as a reinforcing material.
More specifically, the present invention relates to a method and an apparatus for producing a high quality FRTP continuous prepreg by uniformly and surely impregnating continuous fiber bundles with a resin.

[Prior Art] FRTP continuous prepreg is a thermoplastic resin molding material impregnated with metal fiber, plant fiber, mineral fiber, organic fiber, glass fiber, etc.
It is widely known that a W ribbon, a UD sheet or a cross sheet is molded, and then these are subjected to press molding, bag molding, FW molding and the like to manufacture structural members and various machine parts. FIG. 4 is a membrane type explanatory view showing an example of a solution impregnation apparatus for producing a FRTP continuous prepreg. This apparatus has an impregnation tank 4 containing a resin solution 6 which is made fluid by dissolving a thermoplastic resin in an appropriate solvent, and the continuous fiber bundle 1 is immersed in the resin solution 6 via guide rollers 3 and 5. And the fiber bundle 1 is impregnated with the resin solution 6. Reference numeral 2 indicates a fiber bundle feeding roller. The fiber bundle 1 that has passed through the resin solution 6 by the above-mentioned device is then subjected to a solvent extrusion step to eliminate the solvent to form a FRTP continuous prepreg with increased viscosity and good moldability. However, it is difficult to completely remove the solvent in the resin solution, and some amount of solvent is mixed in the resin, and the properties of the resulting FRTP continuous prepreg and the molded products produced using them are deteriorated. Was causing

Therefore, hot melt method (pultrusion method) and fluidized bed method have been developed as a method for producing FRTP continuous prepreg without using a resin solution. FIG. 5 is a schematic explanatory view showing an example of impregnation by the hot melt method. Molten resin 12 is housed inside a high temperature tank 10 which is kept at a high temperature by providing an orifice 13 at the bottom and a heater 11 and the fiber bundle 1 is introduced from the upper opening of the high temperature tank 10. .
The prepreg that has been dipped in the molten resin 12 and then pulled out by the orifice 13 has its shape adjusted by the banding rollers 8a and 8b and is further sent to the heating roller 9,
It is considered that the prepreg is reheated in the heating roller 9 to give sufficient fluidity to the resin so that the resin can be impregnated inside the fiber bundle.

The other conventional technique, the fluidized bed method, is a method of manufacturing a sheet-shaped FRTP continuous prepreg by immersing a cloth sheet or a UD sheet-shaped fiber sheet in the molten resin contained in a high temperature tank and passing it through. is there.

[Problems to be Solved by the Invention] A drawback of the above-mentioned hot melt method or fluidized bed method is that it is very difficult to keep the temperature of the molten resin in the high temperature tank uniform. That is, since the molten resin has poor thermal conductivity, temperature non-uniformity occurs in the high temperature tank, which causes variations in viscosity in the molten resin, resulting in partial impregnation of the resin and air bubbles inside the fiber bundle. Is often left. For this reason, a heating roll 9 etc. is separately provided and a heating press step is added to forcibly impregnate the resin liquid and discharge bubbles. However, the bubbles remaining inside the fiber bundle cannot be completely extracted and the final molded product is obtained. Is causing the deterioration of the nature of.

In addition, due to the above-mentioned variations in the viscosity of the molten resin, the prepreg strength becomes uneven due to insufficient impregnation into the fiber bundle, or the friction resistance between the fiber bundle and the low temperature molten resin portion. As a result, the problem that the part that is easily cut is formed due to the increase in Further, in order to increase the fluidity of the resin, the heating is performed to a temperature close to the decomposition temperature of the thermoplastic resin, and even if the heating roller 9 is added, the amount of energy wasted is enormous. In particular, when a high melting point heat resistant resin such as polyether ether ketone or polyether sulfone is used, the above inconvenience becomes more remarkable.

Therefore, the present inventors have developed a technique capable of uniformly and surely impregnating the molten resin into the inside of the fiber bundle without consuming more energy than necessary, and producing a high quality FRTP continuous prepreg. As a result of various studies,
The present invention can be completed.

[Means for Solving Problems] The apparatus for producing a FRTP continuous prepreg of the present invention, which can achieve the above object, is connected to an extrusion part of a resin extruder and stores the molten resin discharged from the extrusion part. A continuous fiber bundle passage portion having a storage portion, an inlet for the continuous fiber bundle at one end thereof, and a nozzle for taking out the continuous fiber bundle at the other end, and an inlet and a storage portion in the continuous fiber bundle passage portion. Between
A widening member that is disposed on the running path of the continuous fiber bundle and that widens the continuous fiber bundle in a band shape by contacting the continuous fiber bundle, and is disposed on the running path of the continuous fiber bundle in the storage unit and widens the width. And a bundling member for bundling the formed continuous fiber bundle.

Further, the method for producing a FRTP continuous prepreg of the present invention is one in which a continuous fiber bundle is passed through the molten thermoplastic resin to be retained.
In the manufacturing method to obtain TP continuous prepreg, the continuous fiber bundle is dispersed and widened into a band shape before entering into the molten resin, and the molten resin that is extruded from the extruder and stored while maintaining the widened state is passed. Then, the continuous fibers widened in the molten resin are bundled, and the bundled continuous fiber bundles are taken out through a nozzle.

[Operation and Embodiment] FIG. 1 is a sectional explanatory view showing a typical embodiment of the device of the present invention. This device is composed of a fiber bundle passage portion Ta for traveling a fiber bundle (hereinafter also referred to as tow) 1 and a molten resin extruding portion Ra, and the resin extruding portion Ra is constructed by providing a rotary screw 21 in a cylindrical casing 32. In the space on the tip side of the rotary screw 21, a fiber bundle passage portion is formed so as to intersect with the extrusion direction.
Make Ta communicate. At the introduction portion 29 of the fiber bundle passage portion Ta, three cylindrical parallel bars 24a, 24b, 24c as widening members are provided in a direction intersecting the traveling direction of the tow 1, and the fiber bundles 1 are alternately arranged. A running locus bent in a V shape is formed (see FIG. 3). A filling portion 28 for introducing the molten resin 12 into the passage portion Ta is formed on the downstream side of the parallel bars 24a to 24c, and on the further downstream side of the filling portion 28, a direction intersecting the traveling direction of the tow 1. The parallel bar 25 and the focusing bars 26a and 26b serving as a focusing member are provided on the above, and the nozzle portion 31 is formed.
Further, a cooler 22 and a prepreg are provided on the downstream side of the nozzle section 31.
A 1C take-up machine 27 is provided to continuously feed the prepreg 1C to the take-up machine 23. The heater 11 is arranged so as to surround the fiber bundle passage portion Ta.
To maintain the temperature of the molten resin 12 constant.

The production of FRTP continuous prepreg using the above apparatus is carried out as follows. The resin 12 melted by the heater (not shown) provided on the outer peripheral surface of the casing 32 and the frictional heat of the rotary screw 21 is fed in the direction of the broken arrow R and reaches the filling portion 28. On the other hand, the fiber bundle 1 is taken in by the take-up machine 27 and meanders between the parallel bars 24a, 24b, 24c provided in the introduction part 29 and enters. The fiber bundle 1 is a parallel bar 24a
By being pushed in a direction orthogonal to the traveling direction by ˜24c, the bundle itself is expanded in the width direction (see FIG. 2), and the fiber bundle 1A reaches the filling portion 28 in a belt-like expanded state. Therefore, the fiber bundle 1A passes through the molten resin 12 in a separated state, and the molten resin is sufficiently impregnated between the fiber yarns to reach the parallel bar 25. In FIG. 1, the fiber bundle 1 is preferably expanded in the width direction before entering the molten resin in order to prevent entrainment of air and to reduce running resistance, but it is not limited to this. Alternatively, the molten resin may rise to the height of the parallel bars 24a to 24c, and the fiber bundle 1 may be spread in the molten resin in the width direction. Next, the fiber bundle 1A is a converging bar 26 whose central portion has a reduced diameter.
Fiber bundles that spread in strips because they passed a and 26b 1
A is refocused (1B in Fig. 1)
Return to Then, the bundled fiber bundle 1B passes through the nozzle portion 31 as a take-out nozzle, the excess resin adhering to the fiber bundle is squeezed up, and the remaining bubbles are prevented more reliably, and the cross-sectional shape of the prepreg 1C And finish the cross-section dimensions as set. The opening shape of the nozzle portion 31 can be set to various shapes such as a circular shape and a rectangular shape, and the fiber content rate (the ratio of the fiber to the prepreg cross-sectional area) can be arbitrarily selected by changing the opening area. Since this fiber bundle is cooled by the cooler 22, it is wound on the winder 10.

The fiber bundle 1 introduced as described above has parallel bars 24a to 24c.
When meandering, it is expanded in the width direction from the focused state,
Since it is formed in a band shape with a thickness of several tens to several hundreds of μm, the resin can be impregnated reliably, and no unimpregnated portion is left inside the fiber bundle as in the conventional case. In the example above, the parallel bar 24a
˜24c, 25 and focusing bars 26a, 26b are fixed type, they may be pivoted so as to freely rotate or positively rotate, or the arrangement position is As shown in FIGS. 2 and 3 (left side view of FIG. 2), the parallel bars 24a to 24b and the focusing bars 26a and 26b may be arranged in the orthogonal direction. The fiber bundle 1 may be formed by a curved surface, may be inclined in an oblique direction with respect to the running path of the fiber bundle, or may have an adjustable bar interval. Any structure may be used as long as it has a structure that expands in the width direction and that the fiber bundle is converged again before reaching the nozzle portion 31.

Further, if the introduction part 29 is sealed with an inert gas such as N ₂ gas or Ar gas, or if it is kept in a vacuum state, the resin 12
It is possible to prevent oxidative deterioration of the prepreg, and if a plurality of fiber bundle passage portions Ta are provided in one resin extruding portion Ra, it is possible to simultaneously manufacture a plurality of prepregs.

Example 1 Carbon fiber was used as a reinforcing material, nylon 6,6 was used as a matrix, and a diameter of 0.9 mm was measured by the apparatus shown in FIG.
TPCF (thermoplastic resin-impregnated continuous fiber prepreg) is manufactured, and the TPCF is processed by a strand cutter to have a fiber length of 3 m.
The pellets were cut into m pieces to give injection pellets, and the pellets were used to obtain molded articles. Furthermore, a kneading method which is a conventional technique for producing pellets for injection molding, that is, a short fiber and a thermoplastic resin are kneaded by an extruder, extruded and then cut, and a molded article is formed by using the pellets as injection molding pellets. Similarly prepared, both molded products were compared by a tensile strength test and a bending strength test. As a result, the molded product using the TPCF obtained according to the present invention is 1.5% less than the conventional product.
It was found that the strength was about twice as high.

The apparatus and method of the present invention are not limited to the above-described embodiments, and include all the apparatus and method which are modified in design in accordance with the gist of the preceding and the following. Further, the TPCF produced by the present invention can be generally used for UD sheet, cross sheet, etc.
Pellets having a limited fiber length can also be produced by cutting, and various molded products can be molded based on these pellets.

[Advantages of the Invention] According to the present invention, resin can be uniformly and surely impregnated without leaving bubbles, and a high quality FRTP continuous prepreg can be manufactured.

[Brief description of drawings]

FIG. 1 is a sectional explanatory view showing a typical embodiment of the device of the present invention, FIG. 2 is an explanatory view showing another example of arrangement of parallel bars and focusing bars, and FIG. 3 is a left side view of FIG. FIG. 4 is a schematic explanatory view of the solution impregnation apparatus, and FIG. 5 is a schematic explanatory view of the hot melt method. 1 ... Fiber bundle, 2 ... Feeding roller 3, 5 ... Guide roller, 4 ... Impregnation tank 6 ... Solution 8a, 8b ... Banding roller 9 ... Heating roller, 10 ... High temperature tank 11 ... Heater, 12 ... Resin 13 ... Orifice, 20 ... Long fiber supply cylinder 21 ... Rotating screw, 22 ... Cooler 23 ... Winding machine, 24a to 24c, 25 ... Parallel bar 26a, 26b ... Focusing bar, 27 ... Take-up machine 28 ... Filling section, 29 ... Introducing section 31 … Nozzle part, 32… Casing

Claims (2)

[Claims] 1. A storage unit, which is connected to an extrusion unit of a resin extruder and stores molten resin discharged from the extrusion unit, has an inlet for a continuous fiber bundle at one end and the continuous end at the other end. A continuous fiber bundle passage portion having a fiber bundle take-out nozzle; and a continuous fiber bundle passage portion disposed between the introduction port and the storage portion in the continuous fiber bundle passage portion on the traveling path of the continuous fiber bundle. A widening member that widens the continuous fiber bundle in a band shape by contacting with the fiber bundle, and a converging member that is disposed on the running path of the continuous fiber bundle in the storage unit and that converges the widened continuous fiber bundle. And a FRTP continuous prepreg manufacturing device. 2. A method for producing a FRTP continuous prepreg by passing a continuous fiber bundle through a thermoplastic molten resin to be stored, wherein the continuous fiber bundle is dispersed and widened into a band shape before being introduced into the molten resin. , Passing through the molten resin that is extruded from the extruder and stored while holding the widened state, then the widened continuous fibers are focused in the molten resin, and the continuous fiber bundle after focusing is A method for producing a FRTP continuous prepreg, which is characterized in that it is taken out through a nozzle.