JPH0552769B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] 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 product having a planar shape into a irregularly shaped product having a cross section of a constant shape, a roll method has been widely adopted as a method for manufacturing steel pipes. A method similar to the forming method is known. That is, by passing continuously between a series of pairs of forming rolls having irregularly shaped cross sections, the heated molded body is gradually bent until it has the desired cross-sectional shape, and then the heated molded body is bent until it has the same cross-sectional shape as 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. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a forming method and an apparatus therefor that can sufficiently degas the air in the material and significantly improve the mechanical strength of the resulting irregularly shaped articles, compared to conventional forming methods. It is in. [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, the method for continuously forming a fiber-reinforced resin molded article according to the present invention is a method of heat-compressing a fiber-reinforced resin molded article having a planar shape into a irregularly shaped article having a fixed cross section. A method in which the molded body is moved intermittently and is heated and compressed between upper and lower molds having irregular cross sections while the molded body is stopped, and then cooled under pressure, the preheating step before the heating and compression shaping. The method is characterized in that the fiber-reinforced resin molded article is preheated and pre-shaped. Furthermore, the apparatus of the present invention is an apparatus for heat-compressing a fiber-reinforced resin molded body having a planar shape into a irregularly shaped article having a fixed cross section, and has a transfer configuration for moving the molded body in small increments. A preheating section for preheating the fiber-reinforced resin molded body, upper and lower molds each having a modified cross-sectional shape for heating compression shaping that opens and closes in coordination with the inching movement, and a modified cross-sectional shape for compression cooling. It is characterized in that it comprises upper and lower molds, and a pre-shaping part is provided in the preheating part of the fiber-reinforced resin molded body. [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 above prepregs 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 heating and compressing them. 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 heating and compression molding include the method described in Japanese Patent Application Laid-Open No. 63-62713. 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. One of the characteristics of the present invention is that pre-shaping is performed in the preheating step, and by combining such a pre-shaping method with the present invention, prepregs can be continuously laminated, molded, and formed. Not only can the material be shaped, but the air in the material can be sufficiently degassed, and the mechanical strength of the obtained irregularly shaped product can be greatly improved. 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 are first sent to a preheating section and 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 preshaped as it is or under heating in the preheating section, and then sent into upper and lower molds having irregular cross sections for heating compression shaping to begin heating compression shaping. . The pre-shaping method involves a so-called roll process in which the heated material is passed through a series of pairs of pre-shaping rolls having irregular cross-sections and gradually bent into the desired cross-sectional shape. One example is the forming method. 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 shaping material is performed, for example, by a roll provided in the preheating section and/or a take-up roll provided at the outlet of the pressurized cooling mold, but the inching is caused by the drive time of the roll, the stoppage of the roll, etc. This can be achieved, for example, by controlling the time with a timer as described below. 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. Further, as for the pressurizing force, high pressure is desirable from the viewpoint of foam, but the disturbance of fiber orientation due to the flow of the softened resin must be taken into consideration. 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, for example, a knockout pin or the like in the heating compression shaping mold and the pressure cooling mold 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, in order to carry out the present invention, a continuous shaping device is equipped with a supply section having a guide roll 1 for supplying a shaping material M. A. Preheating section B having a guide roll 2 for transferring the shaping material, a plurality of pairs of preforming rolls 3 for preshaping, and a far infrared heater (not shown) for preheating, heating compression It is composed of a compression forming part C which is a forming mold 4, a compression cooling mold 5, and a hydraulic unit 6, and a taking part D having a taking roll 7 for taking the molded product after shaping. The shaping material M is sent to the preheating section B via between the guide rolls 1 of the supply section A. When entering the preheating section B, the shaping material M heated above the glass transition point of the thermoplastic resin, preferably above the softening point, passes between multiple pairs of preforming rolls 3 as shown in FIG.
The shapes of each roll pair 3-(1) to (5) are sequentially pre-shaped. The spacing between each pair of rolls 3-(1) to (5) shown in FIG. 2 is constructed so as to be adjustable according to 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 nip pressure is sufficient as long as it is a pressure sufficient to preshape the shaping material, and should be determined experimentally. The material thus preformed is then sent to the heating compression mold 4 of the compression shaping section C, where it is compressed and shaped by the hydraulic unit 6. The heating temperature of the mold is preferably maintained at the glass transition point, preferably melting 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 5, where it is compressed and cooled by a hydraulic unit 6 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 6 is designed to be used in conjunction 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 shaped material is transferred using any one of the guide roll 1 in the supply section A, the guide roll 2 in the preheating section, the preforming roll group 3, and the take-up roll 7 in the take-off section D, or a combination of these rolls. This is done by inching the roll group. 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 4 and the compression cooling mold 5 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 shaping material is moved for a certain period of time by a roll drive timer, and at the same time as the timer runs out, the compression shaping timer is activated.
The timer expires after compressed shaping for a certain period of time. At the same time, the roll drive timer starts operating again.
Restart the movement of the shaping material. 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, the surfaces of the guide roll, the preforming roll, the heating compression molding mold 4 and the compression cooling mold 5 of the compression molding part C, which are present in the preheating section B, have mold releasability from the resin. It is preferable to consider. 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 UBE” manufactured by Ube Industries, Ltd.) is applied.
A process such as baking a varnish (such as ``U varnish'') is performed, 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 also be applied before or during operation. In this embodiment, it is preferable that the hot compression molding mold 4 and the compression cooling mold 5 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 when the mold is opened, and to release the excipient material from the mold. . In the same figure, for example, when a knockout pin is provided in the lower mold, a push rod 32 is moved via a push plate 31 by an air cylinder (not shown) at the same time as the mold is opened, and this causes the knockout to be removed. pin 3
3 rises to release 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. Also, if 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 on the preheating section side (to take an R shape) because it facilitates the movement of the molding material. The heating compression forming mold 4 and the compression cooling mold 5 may each be configured as a separate pair of molds. In this case, it is preferable that the heating compression molding mold 4 and the compression cooling mold 5 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 5. Further, as shown in FIG. 4, 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-16 are symbols representing temperature divisions. For example, the preheating section B is T-1 to T
Divide into 8 parts, T-1 at 200℃, T-2 at 210℃, T3
220℃, T-4 to T-7 230℃, T8 240℃
After preforming, the heating compression molding section _C1 may be heated to T-9 to T-12.
The temperature of each section is adjusted to 200℃, and then the compression cooling section _C2 is divided into T-13 to T-16, each of which is heated to 100℃.
You can also adjust the temperature. 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 times N of molding is expressed as l(S·T). or,
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 4 and the compression cooling mold 5 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 cross-sectional shape of the pre-shaping roll, the heating compression molding mold, and the compression cooling mold, it is possible to shape the material into irregular cross-sections such as angles and channels. [Example] The present invention will be explained below 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 preheating section, preforming roll 3, take-up roll 7 in the take-up section Circumferential speed of drive roll: 5 cm/sec Preheating section heating method: Temperature is adjusted in 8 categories as shown in Figure 4 using a far-infrared heater Adjustment Heating compression shaping mold, compression cooling mold: A pair of upper and lower molds with a length of 100cm are each divided into four parts and the temperature is adjusted to form a heating compression shaping part and a compression cooling part in the same mold. I let it happen. 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. 4. 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.
was introduced into the preheating section B via the. The introduced shaping material M is preheated in the preheating section B where the temperature of T-1 to T-3 is adjusted to 180°C. Next, the preforming roll T- is moved by a drive roll group with a roll drive timer set to 1 second, and is heated to 200°C.
4 to T-8 (see FIG. 2 for structure). Next, the preshaped shaping material is T-9 to T
-12 is sent to heating compression shaping section _C1 heated to 180℃, compression shaping timer is 30 seconds, shaping pressure is 20Kg/
It was heated and shaped by a hydraulic unit 6 adjusted to cm ² . Then, after heat shaping, T-13 to T-14 were
℃, T-15 to T-16 are sent to a compression cooling section _C2 whose temperature is adjusted to 50℃, and after being compressed and cooled by the unit 6, they are taken by a take-up roll 7 to form an irregular cross section as shown in FIG. An excipient having the following properties was obtained. 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. In addition, the bending strength retention rate and flexural modulus retention rate of the obtained excipient product (relative percentage of the bending strength and flexural modulus of the excipient material when the bending strength and flexural modulus of the excipient material are set to 100) The result is 85 each.
%, 90%. In addition, the porosity of the excipient was measured and was 3.1%. Note that the porosity is a value determined from the specific gravity of the excipient and the weight content of the fibers. Comparative Example 1 In Example 1, preforming rolls T-4 to T
When the only difference was that -8 was not used, the obtained excipient had a bending strength retention rate of 55%, a bending elastic modulus retention rate of 60%, and a void ratio of 13%. Comparative Example 2 A shaped article having the irregular cross section shown in FIG. 5 was obtained from the shaping material used in Example 1 using the apparatus shown in FIG. 6. That is, the above-mentioned shaping material was introduced into the preheating section 60 whose temperature was controlled to 200° C. by a far-infrared heater. The shaping material preheated on the guide roll 61 is then transferred to the shaping section 62 whose temperature is maintained at 180°C.
It was shaped by passing between shaping rolls arranged as shown in the figure. The shaping roll used had a cross-sectional shape shown in FIG. Also, the forming pressure is linear pressure.
It was 20Kg/cm. Here, the linear pressure indicates the force per unit width of the shaping material. After shaping, the product was cooled to 50° C. by passing between cooling rolls under a linear pressure of 20 kg/cm to obtain a shaped product. When the bending strength retention rate and bending elastic modulus of the excipient were determined, they were 70% and 80%, respectively, which were lower values compared to Example 1. Furthermore, when the porosity was determined, it showed a high value of 8%. Example 2 Unidirectional carbon fiber/polycarbonate resin prepreg with fiber direction from long layer at 0°C/90°C/0°C/30
℃/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 with a fiber content volume % of 0%, which was laminated and molded 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 87% and 92%, 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】

〔Effect of the invention〕

According to the present invention, the degassing during shaping is sufficient compared to the conventional technology, so that the mechanical strength of the obtained shaped product can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing one embodiment of the present invention, Fig. 2 is a sectional view of a preforming roll, and Fig. 3 is an example of a heating compression forming mold, a compression cooling mold, and a knockout pin. 4 is a schematic side view showing a state in which the preheating section, heating compression shaping section and compression cooling section are divided into a plurality of temperature sections, and FIG. 5 is an example of a shaped product obtained by the present invention. FIG. 6 is a schematic side view showing an embodiment of the prior art.

Claims (1)

[Claims] 1. A method of heating and compressing a fiber-reinforced resin molded article having a planar shape into a irregularly shaped article having a fixed cross section, in which the molded article is moved intermittently and the molded article is stopped. This is a method in which the fiber-reinforced resin molded body is heated and compressed between upper and lower molds having irregular cross sections, and then cooled under pressure in the preheating step before the heating and compression shaping. A method for continuously shaping a fiber-reinforced resin molded article. 2. The method for continuously forming a fiber-reinforced resin molded article according to claim 1, wherein the same portion of the molded article is heated, compressed, and cooled at least twice. 3. An apparatus for heat-compressing a fiber-reinforced resin molded body having a planar shape into a differently-shaped molded product having a fixed cross section, which has a transfer configuration for moving the molded body in increments, and preheats the fiber-reinforced resin molded body. and upper and lower molds having irregular cross-sectional shapes for heating and compression forming, and upper and lower molds having irregular cross-sectional shapes for compressing and cooling, which open and close in coordination with the inching movement. 1. A continuous shaping device for a fiber-reinforced resin molded article, characterized in that the preheating section of the fiber-reinforced resin molded article is provided with a pre-shaping section. 4. The fiber-reinforced resin according to claim 3, wherein the upper and lower molds having irregular cross-sectional shapes for heating compression shaping and the upper and lower molds having irregular cross-sectional shapes for pressurized cooling are adjacent to each other. Continuous shaping device for molded objects. 5. The continuous shaping device for fiber-reinforced resin molded bodies according to claim 3 or 4, characterized in that the heating compression shaping mechanism and the pressure cooling mechanism are provided in the same upper and lower molds.