JPH0369701B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for continuously shaping a fiber-reinforced resin molded article and an apparatus suitable for carrying out the method. [Prior Art] Conventionally, as a method for continuously shaping a fiber-reinforced resin molded article having a planar shape into a irregularly shaped article having a constant cross-section, a roll-form method, which is widely adopted as a method for manufacturing steel pipes, has been used. A method similar to the mixing method is known. That is, the heated molded body is gradually bent into the desired cross-sectional shape by passing it continuously between a series of pairs of forming rolls having irregular cross-sections, and then the heated molded body is bent into the desired cross-sectional shape. This method attempts to shape the material by cooling it under pressure while passing it between a plurality of rolls having a cross section of . [Problems to be Solved by the Invention] However, in the above method, pressure cooling is performed between the rolls, so the molded body is pressurized while it is sandwiched between the pair of rolls. When separated, the molded body is in an open state, that is, there is no pressure, so
Due to the springback of the molded body, air in the material cannot be sufficiently degassed, resulting in a disadvantage that the mechanical strength of the obtained irregularly shaped article is significantly reduced. Therefore, in a patent application dated 13, 1985 (title of invention: continuous shaping method and apparatus for fiber-reinforced resin moldings), the present inventors previously proposed a fiber-reinforced resin molding having a planar shape. A method and apparatus for heating and compressing a body into an irregular shaped article having a fixed cross section, in which the molded article is moved intermittently, and upper and lower molds having an irregular cross section are provided while the molded article is stopped. We proposed a technology in which the material is heated, compressed, and then cooled under pressure (hereinafter referred to as the "previously proposed technology"). As a result of further research, the present inventors found that in the previously proposed technology, when preforming is performed, the circumference of each part of the roll differs in the width direction of the roll. The circumferential speed of the material, that is, the moving speed of each part in the width direction of the material to be shaped, is different, and this causes the material to meander, making it difficult to form it stably.Furthermore, the fiber orientation after pre-shaping is disturbed. It has been found that there is a problem in that the mechanical strength of the obtained excipient is reduced. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method and apparatus for continuously forming a fiber-reinforced resin molded article, which does not cause meandering of the forming material and therefore enables stable forming. Another object of the present invention is to provide a method and apparatus for continuously forming a fiber-reinforced resin molded article, which can produce a shaped article with excellent mechanical strength without disordered fiber orientation. . [Means for Solving the Problems] In order to achieve the above object, the present inventors have made extensive studies and have completed the present invention. That is, in the continuous forming method of a fiber-reinforced resin molded article of the present invention, a fiber-reinforced resin molded article having a planar shape is intermittently preheated and pre-shaped, and then heated and compressed between upper and lower molds having irregular cross sections. In a method of forming a irregularly shaped article having a cross section of a substantially constant shape by compressing and cooling, the heights of both ends and the center of a fiber-reinforced resin molded article having the above-mentioned planar shape are determined in the pre-shaping. It is characterized by changing the difference continuously or intermittently. Further, the continuous shaping device for fiber-reinforced resin molded bodies of the present invention includes a pre-shaping section for preheating and pre-shaping the fiber-reinforced resin molded bodies, and upper and lower metal molds having irregular cross-sectional shapes for heating and compression shaping. In a continuous shaping device for a fiber-reinforced resin molded body, which is equipped with a mold and upper and lower molds having irregular cross-sectional shapes for compression cooling, a preheating heater for preheating the pre-shaping section and the fiber-reinforced resin molded body are provided. It is characterized by comprising an end holding part and a center holding part for continuously or intermittently changing the difference in height between both ends and the center part. [Structure of the Invention] The present invention will be explained in detail below. The excipient material used in the present invention is a unidirectional fiber-reinforced resin sheet (hereinafter referred to as UD
There are multi-directional fiber-reinforced resin sheets (hereinafter referred to as woven prepreg) made by impregnating a woven fabric such as plain weave, satin weave, or twill weave with the above resin (hereinafter referred to as woven fabric prepreg), and nonwoven fabric prepreg made by impregnating a nonwoven fabric such as matte.
The prepregs described above can be used alone or in combination to form a fiber-reinforced resin molded article of the present invention by laminating them so as to have a desired fiber orientation and thickness, or by heat compression molding. In particular, it is preferable to carry out hot compression molding before the continuous shaping of the present invention, since this makes it possible to remove the air present between the prepregs, thereby improving the physical properties of the resulting shaped article. Examples of the method of hot compression molding include the method shown in Japanese Patent Application No. 61-207618. That is, this is a method in which the prepreg is stacked and sent between upper and lower belts that move in small increments, and then, while being sandwiched between the belts, preheating, heating compression molding, and compression cooling are performed to continuously mold the prepreg. By combining such a method with the present invention, it is also possible to continuously laminate, mold, and shape prepregs. The fibers used in the present invention include glass fibers, carbon fibers, and aramid fibers (registered trademark "Kevlar").
etc.), inorganic fibers such as silicon carbide fibers, titanium fibers, boron fibers, metal fibers such as stainless steel, etc., but are not limited to these. On the other hand, thermoplastic resins include polystyrene,
Polyvinyl chloride, high density polyethylene, polypropylene, nylon, polycarbonate, polybutylene terephthalate, polyethylene terephthalate, polyether sulfon, polysulfon,
Examples include, but are not limited to, polyetherimide (trademark "ULTEM", etc.), polyetheretherketone, polyphenylene sulfide, and the like. It is preferable that the laminated prepregs or the shaping material integrated by heating compression molding be sent to a pre-shaping section and first preheated. The preheating temperature is generally set to be higher than the glass transition point of the thermoplastic resin. The preheated shaping material is then heated so that it does not move in the height direction, for example by pinching both ends of the material with pinch rolls or holding it in a fixed groove, and the central part of the shaping material is The height direction changes continuously or stepwise with respect to the pinch roll or fixed groove, and is arranged so that the final height is the same as the difference in height between the end and center of the target shaped product. It is gradually preformed while being brought into contact with a group of rolls such as a guide roll or nip roll, a plate body such as a flat plate or a curved plate, or a rod-shaped body such as a round bar or square bar, while being pulled in the longitudinal direction. In addition, contrary to the above, it is also possible to perform preliminary shaping by moving both ends of the shaping material in the height direction and fixing the central part of the shaping material in the height direction. Of course, it is possible to drive the pinch rolls, guide rolls, etc. The material to be preshaped as described above is then fed into upper and lower molds having irregular cross sections for heating and compression shaping, and heating and compression shaping is started. The upper and lower molds are open while the material to be shaped is moving, and as soon as the material stops, the upper and lower molds are closed to perform heating compression shaping. Therefore, the material moves by inching. By adjusting the amount of movement at one time, it becomes possible to heat and compress the same portion of the material a desired number of times. Therefore, after being heated and compressed once in the mold, it may be sent to the next pressurization and cooling process, but from the viewpoint of degassing the material, it is necessary to apply the same portion multiple times. It is preferable to heat and compress. Note that the movement of the shaped material is performed, for example, by a roll provided in the pre-shaped section and/or a take-up roll provided at the outlet of the pressurized cooling mold.
The inching is achieved by, for example, controlling the driving time and stopping time of the roll with a timer as described later. The heating temperature is higher than the glass transition point, preferably the softening point, of the thermoplastic resin, and from the viewpoint of defoaming, a higher temperature is generally preferable, but it is determined experimentally for each resin in consideration of releasability from the mold. It should be. It is particularly preferable to treat the mold with a mold release agent before or during operation in order to improve the releasability of the excipient material from the upper and lower molds. As for the pressing force, high pressure is desirable from the viewpoint of defoaming, but it is necessary to take into account the disturbance of fiber orientation due to the flow of the softened resin. Therefore, it is desirable to determine the pressure experimentally based on the fiber content in the excipient material, but generally the higher the fiber content, the higher the pressure can be set. The shaped material that has been heated and compressed is sent to a compression cooling mold and compressed and cooled once or multiple times, so that a fiber-reinforced resin molded article can actually be obtained continuously. The cooling temperature is preferably set below the glass transition point of the thermoplastic resin. This is because demolding at a temperature exceeding the glass transition point generally causes problems such as warping of the excipient and bubbles remaining on the surface of the excipient.
Further, the pressurizing force may be set independently from the pressurizing force at the time of heating and pressurizing shaping, but it is usually set to the same pressure. Incidentally, it is particularly effective to provide a knockout pin or the like in the heating compression shaping mold and the compression cooling mold, for example, to prevent the molded product from coming out of the mold. The knockout pin is housed in the mold when pressurized, and functions by protruding from the mold surface as soon as the mold opens, so the movement of the pin is the same as the movement of the mold. It should be linked with
Such movement of the pin can be achieved, for example, by springs, air pressure, etc., but in particular when using air pressure,
For example, this is possible by linking the operation of an air cylinder with the opening and closing of a mold. Next, details of the present invention will be explained based on typical embodiments shown in the accompanying drawings. FIG. 1 is a schematic side view showing one embodiment of the present invention, and as shown in the figure, a continuous shaping apparatus for carrying out the present invention has a guide roll 1 for supplying a shaping material M. Part A, a guide roll 2 for transferring the shaped material, a guide rail 3 having a U-shaped groove for holding both ends of the shaped material and moving the both ends in the height direction, and a guide rail 3 for transferring the shaped material; A preforming part B having a flat plate 4 for holding the height of the center portion so that it does not change with the movement of both ends, and a far infrared heater (not shown) for preheating, and a heating compression molding mold. 5, a compression shaping section C having a compression cooling mold 6, and a hydraulic unit 7, and a taking-off section D having taking-off rolls 8 for taking off the molded product after shaping. The shaped material M is sent to the preliminary shaping section B via between the guide rolls 1 of the supply section A. When entering the pre-shaping section B, the shaping material M heated above the glass transition point of the thermoplastic resin, preferably above the softening point, is heated to a temperature above the softening point of the thermoplastic resin.
It is preformed into a desired shape while passing through a guide rail 3 and a flat plate 4 having a U-shaped groove as shown in the figure. Further, in the present invention, the material may be preformed into a desired shape when passing between the pinch rolls 21 and nip rolls 22 and 23 shown in FIGS. 6 to 8. In addition, a preliminary shaping mold 62 shown in FIGS. 9 to 11
The material may be pre-shaped into a desired shape while being passed between a roll 61 for pressing both ends of the material and a roll 63 for pressing the center of the material. The preforming mold 62 may be heated to a temperature above the glass transition point, preferably the softening point, of the thermoplastic resin using a sheathed heater or the like, or it may be provided in a heating compression mold. In addition, by arranging the roll 61 so that its central axis takes a certain angle θ with respect to the drawing direction of the shaped material as shown in the figure, tension is generated in the width direction of the shaped material.
Preferable from the viewpoint of preventing wrinkles. Of course, the angle θ may be 0 degrees. In the above embodiment, it is preferable that the spacing between each pair of rolls and the spacing between the preforming mold and the rolls can be adjusted in accordance with the thickness of the shaping material. It is also possible to pre-shape the shaping material under pressure, for example by using an air cylinder or the like. The above-mentioned pressing force is sufficient as long as it is a pressure sufficient to pre-shape the shaping material, and should be determined experimentally. The material thus preformed is then sent to the heating compression mold 5 of the compression shaping section C and compressed and shaped by the hydraulic unit 7. The heating temperature of the mold is preferably maintained at a temperature equal to or higher than the glass transition point of the thermoplastic resin using a heater, steam, or the like. On the other hand, the heated and compressed portion is then sent to a compression cooling mold 6, where it is compressed and cooled by a hydraulic unit 7 to below the glass transition point of the thermoplastic resin. As a cooling method, a method using a refrigerant such as air cooling, water cooling, or steam cooling is adopted. Although the hydraulic unit 7 is designed to be used in combination with hot press molding, it is of course possible to provide separate hydraulic units for hot press molding and compression cooling, and set the pressurizing force independently. Pressure force is 0.1~500
Kg/cm ² is preferred. In the present invention, the shaping material is transferred by the guide roll 1 in the supply section A, the guide roll 2 in the preforming section, the pinch roll 21 (if provided), the nip rolls 22 and 23 (if provided), and the guide roller 2 in the take-up section D. This is carried out by moving one of the take-up rolls 8 or a group of rolls in combination. Therefore, the shaping material is moved by an inch. That is, in the compression shaping section C, the driving of the heating compression shaping mold 5 and the compression cooling mold 6 is stopped immediately before they are closed, shaping is continued for a certain period of time, and the driving is restarted as soon as both molds are opened. By repeating this operation, the excipient material is actually moved continuously. The above-mentioned inching drive can be controlled by, for example, two timers, one for driving the roll and one for compression shaping. That is, the excipient material is moved for a certain period of time by a roll drive timer,
At the same time as the timer expires, the compression and shaping timer is activated, and the compression and shaping is performed for a certain period of time, and then the timer expires. At the same time, the roll drive timer is activated again and the movement of the shaping material is resumed. Note that the above method is an example, and the method is not limited to this, and automatic control can also be performed using a microcomputer. Among the rolls used in the present invention, portions that come into contact with the shaping material, such as the guide roll 2, pinch roll 21, and nip rolls 22 and 23 existing in the preforming section B,
It is preferable that the surfaces of the heating compression molding mold 5 and the compression cooling mold 6 of the compression molding section C take into consideration mold releasability from the resin. Therefore, it is desirable that these surfaces be mirror-finished or subjected to an appropriate mold release treatment. Specifically, the roll surface is treated with Teflon, or imide resin (“UPiLEX” manufactured by Ube Industries, Ltd.) is used.
UBE U varnish, etc.), etc.), but when selecting it, it is necessary to consider the imprinting temperature. A suitable mold release agent may also be used, such as FREKOTE (USA).
FREKOTE) etc. can be applied before or during operation. In this embodiment, it is preferable that the heating compression molding mold 5 and the compression cooling mold 6 be provided with knockout pins as shown in FIG. Providing this is preferable because it facilitates the removal of the shaping material from the mold. The knockout pin is housed in the mold when the mold is closed, but functions to protrude from the mold as soon as the mold is opened, and to release the excipient material from the mold. . In the figure, for example, when a knock-out pin is provided in the lower mold, when the mold is opened, the push rod 32 is moved via the push plate 31 by an air cylinder (not shown), and thereby The knockout pin 33 rises to remove the shaping material from the mold.
On the other hand, at the same time as the mold is closed, the air cylinder retreats, and the push rod 32, knockout pin 33, and push plate 31 function by returning to their original positions due to the downward force exerted by the spring 34 and the shaping material. In addition, when the knockout pin is provided in the upper mold,
When the mold is closed, the knockout pin 35 is pushed up by the pushing force of the molding material, but as soon as the mold is opened, the molding material is pushed down by the force of the spring 36 and removed from the mold. It is something that makes you Note that the above method is an example, and the method is not limited thereto. Further, it is preferable to round the end of the heating compression molding mold 5 on the side of the preforming section B (to form an R) to facilitate the movement of the molding material. The heating compression molding mold 5 and the compression cooling mold 6 may each be configured as a separate pair of molds. In this case, it is preferable that the heating compression shaping mold 5 and the compression cooling mold 6 are placed adjacent to each other so that the temperature of the heated compression molded part does not decrease before the part is transferred to the compression cooling mold 6. Further, as shown in FIG. 13, it is also possible to provide both heating and cooling functions by dividing the inside of the pair of upper and lower molds into a plurality of temperature zones and controlling the temperature. In the figure, T-1 to T-10 are symbols representing temperature divisions. For example, the preforming part B is T-1
～Divided into T-2, T-1 at 200℃ and T-2 at 210℃
After preforming, the heating compression shaping section C ₁ is divided into T-3 to T-6 and the temperature of each is adjusted to 200°C, and then the compression cooling section C ₂ is divided into T-3 to T-6. It is also possible to divide it into T-7 to T-10 and adjust the temperature of each to 100°C. In the present invention, the same portion of the excipient material can be compression molded multiple times, and the number of times is determined by adjusting the excipient material movement time, that is, the excipient material movement timer. That is, the length of the heating compression shaping mold is l (cm), and the moving speed of the shaping material is S.
(cm/sec) and the moving time of the shaping material is T (sec), the number of molding times N is expressed as l/(S·T).
Further, the time for one compression molding is determined by adjusting the compression molding timer. Note that the number of times and time of heating compression molding may be different from the number and time of compression cooling, and in this case, means such as changing the lengths of the heating compression molding mold 5 and the compression cooling mold 6 may be used. . As mentioned above, by moving the shaping material by inching, the shaping material is actually continuously preheated, preshaped, heated and compressed, and compressed and cooled to continuously form a cross section of a constant shape. It can be shaped into a differently shaped article having the following characteristics. It goes without saying that by changing the position and shape of the rolls used in the pre-shaping section and the cross-sectional shape of the heating compression shaping mold and compression cooling mold, it is possible to shape irregular cross sections such as angles and channels. be. [Example] Hereinafter, the present invention will be explained with reference to Examples. Example 1 The specifications and conditions of each part of the apparatus shown in FIG. 1 were as follows. Driving rolls: Guide roll 2 in the preforming section, take-up roll 8 in the take-up section Circumferential speed of drive roll: 5 cm/sec Pre-forming section heating method: Temperature-controlled heating in two sections as shown in Figure 13 using a far-infrared heater Compression molding mold, compression cooling mold: A pair of upper and lower molds with a length of 100 cm are each divided into four parts and the temperature is adjusted to form a heating compression molding part and a compression cooling part in the same mold. . The heating method used was a sheathed heater. The temperature divisions of the preheating section, heating compression shaping section, and compression cooling section were as shown in FIG. 13. A flat plate-like 2 mm thick laminate molded product containing 40% by volume of polycarbonate resin and reinforced with plain-woven carbon fiber weave, that is, excipient material M, is placed on the guide roll 1 of supply section A.
It was introduced into the preforming section B via the. The introduced shaping material M has T-1 and T-2 of 180°C, respectively.
It is preheated in preforming section B whose temperature is controlled to 200°C. Next, preliminary shaping was performed while passing through the guide rail 3 and flat plate 4 in the form shown in FIGS. 2 and 4 and 5. Note that the roll drive timer for moving the shaping material was set to 1 second. The pre-shaped material is T-3 to T-6.
It is sent to heating compression shaping section _C1 heated to 180℃,
Heat shaping was carried out by the hydraulic unit 7, which was adjusted to a compression shaping timer of 30 seconds and a shaping pressure of 20 kg/cm ² . Then, after heat shaping, T-7 to T-8 were heated to 100°C.
Compression cooling section where T9 to T-10 are temperature controlled to 50℃
After being compressed and cooled by the unit ₇ ,
The product was taken up with a take-up roll 8 to obtain a shaped article having an irregularly shaped cross section as shown in FIG. Heat compression forming section under the setting conditions of each section above
The residence time T and the number of pressurization times N of the shaping material in each of C ₁ and compression cooling section C ₂ were determined using the following equations. Residence time T = (a x b) / (c x d) Number of times of pressurization N = a / (c x d) where a = length of heating compression shaping section (compression cooling section) b = compression molding timer setting value c = Circumferential speed of the drive roll d = Roll drive time As a result, the residence time and number of pressurizations are 5 minutes and 10 minutes, respectively.
It was hot. During operation, the preforming material could be smoothly preformed without meandering in the preforming section, and when the arrangement of the fibers was observed using soft X-rays, no disorder of the fibers was observed. The flexural strength retention rate and flexural modulus retention rate of the obtained excipients (the flexural strength and flexural modulus of the excipient material are 100
The relative percentages of bending strength and bending elastic modulus of the excipient were found to be 90% and 95%, respectively. Comparative Example In Example 1, instead of the guide rail 3 and flat plate 4 shown in FIG. 1, shaping rolls 91 to 95 shown in FIG. 15 were arranged, and the shaping material was passed between the pair of preliminary shaping rolls. Except for preforming by letting
An attempt was made to obtain the shaped product shown in FIG. 14 in the same manner as in Example 1. However, when passing between the pair of preforming rolls, the material to be shaped meandered and could not be preformed smoothly. Furthermore, when the arrangement of fibers in the excipient was observed using soft X-rays, disorder was observed. When the bending strength retention rate and bending elastic modulus of the excipient were determined, they were 85% and 90%, respectively, which were lower values compared to Example 1. Example 2 Unidirectional carbon fiber/polycarbonate resin prepreg with the fiber direction from the surface layer at 0°C/90°C/0°C/90
℃/0℃/90℃/0℃/0℃/90℃/0℃/90
A shaped product was obtained in the same manner as in Example 1, except that a flat plate having a fiber content of 60% by volume, which was laminated in the order of 0°C/0°C/90°C/0°C, was used as the shaping material. When bending strength retention rate and bending elastic modulus were determined,
The percentages were 92% and 95%, respectively. Examples 3 to 6 Using the apparatus used in Example 1, flat plates made of the combinations of the resins and reinforcing fiber woven fabrics shown in Table 1 were obtained in the same manner as in Example 1 under the conditions shown in Table 1.

[Table] As shown in Table 1, Examples 1 to 3 show the influence of the number of times of pressurization on the physical properties of excipients. Both obtained high results. Further, in Examples 5 and 6, shaping was performed using a combination of other thermoplastic resins and fibrous fabrics, and good results were obtained in both cases. [Effects of the Invention] According to the present invention, the problem of meandering of the material to be shaped is solved when preforming, so not only stable shaping is possible, but also the fiber arrangement in the obtained shaped product is improved. This has the effect of providing a shaped product with less disturbance in the structure and excellent mechanical strength.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing one embodiment of the apparatus used in the present invention, Fig. 2 is a schematic side view of the preforming section of the same, and Fig. 3 is a bottom heating compression forming device used in the above embodiment. FIG. 4 is a schematic plan view of the guide rail and flat plate of the preheating and forming part of the apparatus shown in FIG. 1, FIG. A schematic side view showing another embodiment of the shaping part, FIG. 7 is a sectional view taken along the line -
FIG. 8 is a cross-sectional view taken along the line ``--'', FIG. 9 is a schematic side view showing another embodiment of the preforming section, FIG. 10 is a schematic plan view of the same, and FIG. 11 is a schematic front view of the same; FIG. 12 is a cross-sectional view showing an example of a heating compression forming part, a compression cooling mold, and a knockout pin;
The figure is a schematic side view showing the pre-shaping section, heating compression shaping section, and compression cooling section divided into a plurality of temperature zones, and FIG. 14 is a cross-sectional view showing an example of a shaped product obtained by the present invention. , FIG. 15 is a schematic side view showing an embodiment of the preforming part in the previously proposed technique.

Claims (1)

[Claims] 1. A fiber-reinforced resin molded article having a planar shape is intermittently preheated and preformed, and then heated and compressed between upper and lower molds having irregular cross sections, and compressed and cooled. In a method of shaping into a irregularly shaped article having a cross section of a constant shape, the difference in height between both ends and the center of the fiber-reinforced resin molded article having the above-mentioned planar shape is continuously or intermittently changed during the pre-shaping. A continuous shaping method for a fiber-reinforced resin molded article. 2. A preforming section for preheating and preshaping a fiber-reinforced resin molded body, upper and lower molds having irregular cross-sectional shapes for heating compression shaping, and upper and lower molds having irregular cross-sectional shapes for compression cooling. In a continuous forming device for a fiber-reinforced resin molded article, the pre-forming section is equipped with a preheating heater for preheating the fiber-reinforced resin molded object, and the difference in height between both ends and the center of the fiber-reinforced resin molded object is continuously measured. , or a continuous shaping device for a fiber-reinforced resin molded article, characterized in that it comprises an end holding part and a central holding part for changing the shape intermittently.