JPH06210644A - Method and apparatus for molding fiber reinforced plastic - Google Patents

Abstract

PURPOSE:To provide a novel method for molding a fiber reinforced plastic molded product constituted so that the pressure required in the impregnation of a fiber reinforcing material with a resin can be reduced and the shrinkage of the resin accompanied by curing during molding can be corrected. CONSTITUTION:A pair of upper and lower molds 1, 2 forming a cavity 3, a liquid sump 12 and the passage 10 allowing both of them to communicate with each other by mating the mating surfaces 6, 7 of both molds 1, 2 with each other are prepared and, after a fiber reinforcing material is placed on the lower mold, the upper and lower molds are mutually mated to be clamped and a liquid resin is injected in a liquid sump 12 from an injection machine in an amt. larger than the amt. necessary for impregnating the fiber reinforcing material but less than the volume of the liquid sump 12. The liquid sump 12 is pressurized by compressed air in such a state that almost all of the liquid resin is stored in the liquid sump 12 and the resin is held in the liquid sump 12 in a liquid or flowable state to send the resin to the cavity 3 from the liquid sump 12 to impregnate the fiber reinforcing material and, subsequently, the resin is integrally cured along with the fiber reinforcing material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a method and apparatus for molding fiber reinforced plastics.

[0002]

2. Description of the Related Art As a method for producing a fiber-reinforced plastic molded article, various methods have been conventionally known. Among them, a pair of male and female molds is used, and a space between the pair of molds is used. That is, the fiber reinforced material is placed on the cavity in advance, and after the mold is clamped, the resin is injected into the mold with a relatively low pressure from the injection hole provided at the appropriate position of the mold, and this resin is applied to the fiber reinforced material. Impregnate, integrate with the reinforcement and cure,
After that, a resin-injection method (hereinafter referred to as RI method) in which a mold is opened and a mold is released to obtain a molded product is widely used.

The resin-injection method for molding by reducing the pressure inside the cavity, that is, the Bakiyumu-assisted resin-injection method (hereinafter referred to as VARI method) is also widely used for molding fiber-reinforced plastics. However, such conventional RI method and VAR
A general method in Method I is to introduce a liquid resin into an injection nozzle, mix a curing agent there, and inject it into a mold. However, in these methods, since there is no mechanism for self-cleaning the inside of the injection nozzle system, after injecting the liquid resin into the mold, the above injection nozzle is removed from the mold, and the inside of the injection nozzle system is further cleaned with a solvent or the like. It is necessary to prevent the resin from being solidified in the system by washing with, which prevents the productivity of the RI method and the VARI method from being improved.

Therefore, in recent years, a mixing head equipped with a self-cleaning mechanism has been developed, which enables molding while the resin injection nozzle is attached to the mold. As a molding method capable of shortening the molding cycle as compared with the RI method by using a curable liquid resin, a structural reaction / injection molding method (hereinafter referred to as S-RIM method) has been developed. .

In general, the RIM method comprises two or more components, which are low molecular weight and low viscosity reactive liquid resin raw materials (for example, a monomer or an initial polymer), are collision-mixed in a mixing head under pressure. At the same time, it is a molding method in which the resin raw material is reacted and cured in the mold by injecting it into a closed mold to obtain a molded product. As is well known, this molding method has been put to practical use in the production of rigid urethane foam molded products and semi-rigid urethane foam molded products. On the other hand, various improvements of the RIM method have been proposed. For example, Japanese Patent Publication No. 61-10286 proposes an improvement of the RIM method so as to compensate the shrinkage of the molded product due to the curing of the liquid resin in the cavity. Has been done.

Among such RIM methods, a method using a milled fiber as a reinforcing material is called an R-RIM method, and a method using long fibers is called an S-RIM method. The above-mentioned raw material injecting machine used in the RIM method is a RIM injecting machine, which is an apparatus for simultaneously mixing the above-mentioned liquid resin raw materials of two or more components under pressure and injecting them into the die. .

FIG. 1 shows a sectional view of an apparatus used in the S-RIM method. In this device, a gap, that is, a cavity 3 is formed between an upper mold 1 and a lower mold 2, and a pressure reducing hole 4 for reducing the pressure inside the cavity is provided in the upper mold. The mold is provided with a liquid resin injection hole 5.
In this device, in order to maintain the reduced pressure in the cavity, a groove is formed on the upper die mating surface 6 or the lower die mating surface 7 or both of them, and a packing 8 is attached thereto. . The mixing head nozzle of the RIM injecting machine 9 is fixed to the liquid resin injecting hole 5, and when molding the fiber reinforced plastic, a required amount of the liquid resin is passed from the RIM injecting machine into the cavity 3 through the flow path 10. Injected.

The S-RIM method is a molding method in which the liquid resin injection device used in the RI method is replaced with a RIM injection machine, and it is possible to shorten the molding cycle and save labor. is there. However, according to the RIM injecting machine, it is possible to inject the resin into the mold while reducing the resin ejection speed, for example, by changing the resin ejection speed from several g / sec to several tens g / sec. It is very difficult to inject into the inside, and RIM with a low resin discharge speed
Since the injection machine has not been developed yet, in particular, when S-RIM molding of a fiber-reinforced plastic molded product having a high fiber content is performed by using the RIM injection machine, it is inevitable to impregnate the fiber reinforcement with the liquid resin. Requires a large injection pressure, and therefore it is very difficult to use a resin foam or the like having a low strength as a core material of a molded product, and a large pressure is generated in the mold. It is also necessary to use.

On the other hand, when the injection speed of the resin is high, the flow speed of the resin in the mold is high, and molding defects such as voids are likely to occur on the surface of the molded product. Furthermore, S-RI
In the M method, since a fast-curing resin is used, the shrinkage accompanying the reaction of the liquid resin becomes relatively large, and due to this shrinkage,
Molding defects such as sink marks are likely to occur on the surface of the molded product.

[0010]

As described above, there are various problems in the molding of the conventionally known fiber reinforced plastics. Therefore, the present invention is based on the RI method and VA described above.
S-RIM solves the problem of low productivity in RI method
Solves the problem that the resin discharge speed and injection pressure in the method are inevitably large, and aims to reduce the resin injection speed into the mold and the resin flow speed within the mold, and impregnate the fiber reinforcement with the resin. It is an object of the present invention to provide a novel molding method and an apparatus for the same, which can reduce the pressure required for the molding and can correct the shrinkage caused by the curing of the resin during molding. .

That is, according to the present invention, the above-mentioned RI method,
A novel fiber reinforced plastic molding method and apparatus for the same are provided, which have the advantages of the VARI method and the S-RIM method, respectively, but do not have the drawbacks thereof.

[0012]

A method of molding a fiber reinforced plastic according to the present invention comprises: (a) a cavity, a liquid reservoir, and a flow path for connecting them by aligning mating surfaces of an upper mold and a lower mold. Prepare a pair of molds to be formed, (b) Place the fiber reinforcement on the lower mold, then clamp the upper mold and lower mold together, and (c) Necessary for impregnating the fiber reinforcement. Injecting a liquid resin in an amount larger than the volume of the liquid reservoir and smaller than the volume of the liquid reservoir from the pouring machine, most of the liquid resin is stored in the liquid reservoir, and (d) the resin is stored in the liquid reservoir. While maintaining a liquid or fluidity, by pressurizing the inside of the liquid reservoir with a compressed gas, the resin is sent from the liquid reservoir to the cavity, the resin is impregnated into the fiber reinforcement,
Next, the resin (e) is characterized by being cured integrally with the fiber reinforcing material.

According to a preferred embodiment of the present invention, in the above-mentioned method, the fiber reinforcement is placed on the lower mold, and after the cooling die is placed on the bottom of the liquid reservoir of the lower mold, the upper mold and the lower mold are separated. The molds are also clamped together, and then the step of injecting the liquid resin into the liquid reservoir and the subsequent steps are performed. According to a further preferred aspect of the present invention, after the mold is clamped, the pressure inside the mold is reduced, and then the liquid resin is injected into the liquid reservoir, and the subsequent steps are performed.

Further, according to a more preferable aspect of the present invention, even after the liquid resin is injected into the liquid reservoir, and then the liquid reservoir is pressurized with a compressed gas, the liquid resin is sent from the liquid reservoir to the cavity. , Continue to pressurize the reservoir with compressed gas,
As the resin in the cavity hardens and shrinks, the resin remaining in the liquid reservoir is sent into the cavity to effectively correct the shrinkage of the obtained molded product.

Further, in the fiber-reinforced plastic molding apparatus according to the present invention, the cavity is formed by aligning the mating surfaces of the upper mold and the lower mold, and the liquid reservoir having the bottom in the lower mold and the flow path for communicating these are formed. To have a pair of molds, and to clamp the upper mold and the lower mold together, and to inject the liquid resin into the pressure reducing hole for reducing the pressure inside the mold and the liquid reservoir of the mold thus reduced in pressure. The liquid resin injection hole for fixing the nozzle of the mixing head of the injection machine and the liquid reservoir are pressurized with compressed gas, and as the resin in the cavity hardens and contracts, A compressed gas pressurizing hole for sending the liquid resin to the cavity through the passage, and a mold part forming the cavity and a mold part forming the liquid reservoir are provided, and the two mold parts are thermally heated. Shut off,
It is characterized by having an adiabatic groove for keeping the temperature of the mold part forming the liquid reservoir lower than the temperature of the mold part forming the cavity.

The method and apparatus according to the present invention are particularly advantageously used for producing a fiber reinforced plastic molded product having a core material of low strength such as a foamed resin or a rubber tube filled with air.

A method and an apparatus for molding a fiber reinforced plastic according to the present invention will be described below in detail with reference to FIGS. 2 to 6. 2 to 5, the same members as those in FIG. 1 are designated by the same reference numerals.

FIG. 2 shows a sectional view of an example of a molding apparatus which can be preferably used for carrying out the method according to the present invention. In this molding apparatus, the upper mold 1 and the lower mold 2 are combined by their mating surfaces 6 and 7,
A cavity 3 as a space is formed between them, and a liquid reservoir 12 having a bottom portion 11 in a lower mold is formed therebetween, and the liquid reservoir and the cavity are communicated with each other through a channel 10. This flow path is also formed along the mating surface of the upper mold and the lower mold. The volume of the sump can hold more liquid resin than is needed to impregnate the fiber reinforcement in the cavity, even after the liquid resin has been sent from the sump to the cavity. The volume is such that the liquid resin remains in the channel.

In the present invention, the means for injecting the liquid resin into the liquid reservoir is not limited at all, but from the viewpoint of productivity, it is preferable to use the above-mentioned RIM injection machine. As the resin injecting machine, a RIM injecting machine will be described.

The upper mold 1 is provided with a compressed gas introduction hole 13 which can be opened and closed by a valve (not shown) so as to communicate with the liquid reservoir 12, and a predetermined amount of the compressed gas introduction hole 13 is provided as described later. Liquid resin is injected into this liquid reservoir from the RIM injector 9, and most of it is once stored in the liquid reservoir, and then compressed gas, usually compressed air, is introduced into the liquid reservoir from the compressed gas introduction hole 13 and The reservoir is pressurized and, as a result, the liquid resin is sent to the cavity 3 in the mold through the flow path 10 to impregnate the fiber reinforcement placed in advance there. As described above, when a predetermined amount of liquid resin is injected into the liquid reservoir from the RIM injector, some of the resin leaks into the cavity through the flow path.

On the other hand, the lower mold 2 is provided with a liquid resin injection hole 5 communicating with the liquid reservoir 12. A mixing head nozzle of the RIM injection machine 9 is detachably attached to the liquid resin injection hole 5, and a predetermined amount of the liquid resin is injected from the RIM injection machine to the liquid reservoir 12 when molding the fiber reinforced plastic. To be done.

As described above, in the present invention, the liquid reservoir 12 has a volume capable of holding a larger amount of liquid resin than that required to impregnate the fiber reinforcing material in the cavity 3. The liquid resin is injected into such a reservoir from the RIM injector in an amount larger than that required for impregnating the fiber reinforcement and smaller than the volume of the reservoir. Therefore, when the injection of the liquid resin into the liquid reservoir is completed, the liquid reservoir has a space above it, and even after the liquid resin is sent to the cavity, the liquid resin remains in the liquid reservoir and the channel. Remains. Therefore, in this way, the liquid resin remains in the liquid reservoir and the flow path, and while the resin cures in the cavity, the liquid resin remaining in the liquid reservoir is continuously pressurized by the compressed gas to The resin can be sent to the cavity in accordance with the shrinkage of the resin, and the shrinkage of the molded article can be corrected.

In the present invention, the liquid resin injection hole 5, and hence the mounting position of the nozzle of the mixing head of the RIM injection machine 9 and the compressed air introduction hole 13 are related to each other in the positional relation of mounting to the mold. However, the present invention is not limited to those illustrated in the drawings. In the present invention, the upper mold and the lower mold are usually heated to a predetermined temperature by a conventional heating means (not shown) introduced into such a mold. By adjusting the heating temperature so that the temperature of the mold portion 15 forming the reservoir is lower than the temperature of the mold portion 14 forming the cavity, the resin in the reservoir is made liquid and at least the fluidity is improved. While holding the resin, the resin in the cavity 3 is cured more quickly than the resin in the liquid reservoir 12, and as described above, the liquid reservoir is pressurized with compressed gas to remove the resin remaining in the liquid reservoir. By sending to the cavity, the shrinkage of the molded product can be effectively corrected.

The temperatures of the respective mold parts 14 and 15 and the temperature difference between them are mainly set appropriately depending on the liquid resin used, but the temperature difference is usually 5 to 5.
It is in the range of 20 ° C.

Thus, according to the present invention, the RIM
When injecting the liquid resin into the cavity 3 from the injecting machine 9, most of the liquid resin is temporarily stored in the liquid reservoir 12, the liquid resin in the liquid reservoir is pressurized with compressed gas, and the liquid resin is passed through the flow path 10 to the cavity. Since the liquid resin is injected into the cavity 3, the flow rate of the liquid resin into the cavity can be reduced, and the pressure required to impregnate the fiber resin with the liquid resin can be reduced. A core material such as foam can also be used as the core material of the fiber reinforcement. Furthermore, by reducing the flow rate of the liquid resin in the cavity, it is possible to prevent the occurrence of voids on the surface of the obtained molded product.

Further, in the present invention, as shown in FIG. 2, the flow path 10 is horizontally formed along the mating surface of the upper mold and the lower mold, and the bottom 11 of the liquid reservoir 12 is formed. It may be substantially in the same plane as the channel 10, but as shown in FIG.
It is preferable that the position is higher than 0. In particular, as shown in the figure, the bottom portion 11 of the liquid reservoir 12 is slightly inclined toward the flow path 10 so that the liquid resin flows into the flow path from the high position. It is preferable to have

FIG. 4 is a sectional view of an example of a molding apparatus in which the inside of the cavity 3 is decompressed so that the method of the present invention can be carried out, and the upper mold 1 and the lower mold 2 as described above are provided. The cavity 3 and the liquid reservoir 12 are formed between them,
In addition to the liquid reservoir and the cavity being connected by a flow path 10, the mold is provided with an openable / closable pressure reducing hole 4 communicating with the cavity 3, and the pressure reducing hole is connected to a vacuum pump (not shown). By connecting to (1), the cavity, the liquid reservoir, and the flow path can be depressurized. Further, a groove 16 is formed in the mating surface of the mold around the cavity and the liquid reservoir so that the cavity, the liquid reservoir and the flow path are kept under reduced pressure, and the packing 8 is mounted in the groove.
The mounting position of the decompression hole 4 on the mold is not limited to the one illustrated in the drawings.

The molding of the fiber reinforced plastic by the molding device capable of reducing the pressure inside the cavity is similar to that described above. The fiber reinforced material is placed on the lower mold 2 and the mold is clamped, and then the pressure reducing hole is formed. Is connected to a vacuum pump to reduce the pressure in the mold, and then the RIM injector is used to inject the liquid resin into the liquid reservoir in the mold, after which the liquid resin is sent to the cavity in the same manner as described above. The molding may be completed by impregnating the reinforcing material and curing the liquid resin together with the reinforcing material.

As described above, according to the present invention, for example, the heating temperature of the mold is adjusted so that the temperature of the mold part forming the reservoir is lower than the temperature of the mold part forming the cavity. Then, while the resin in the cavity is cured more quickly than the resin in the liquid reservoir, and while the resin remaining in the liquid reservoir is kept in a liquid state or at least has fluidity, the liquid reservoir is pressurized to To the cavity, the shrinkage of the molded product can be effectively corrected.

However, as described above, even if a temperature difference is provided between the mold portion forming the cavity and the mold portion forming the liquid reservoir by the heating means provided in the mold, these two molds are not provided. The parts thermally affect each other, and the liquid resin in the liquid reservoir hardens over time due to the heat from the mold, so for example, the liquid resin remains in a thick layer in the liquid reservoir. The temperature of the mold part, which is lower in temperature than the mold part that forms the cavity, is hard to be transmitted to the resin in the liquid pool, and as a result, the resin in the liquid pool hardens. Heat builds up and, in some cases, the resin in the sump cures faster than the resin in the cavity. On the other hand, if the amount of resin stored in the liquid reservoir is set to a relatively small amount and most of it is transferred to the cavity with compressed air during molding, the purpose of correcting shrinkage of the molded product with excess resin in the liquid reservoir Not only may it not be realized, but compressed resin may enter the cavity when the resin is transferred from the liquid reservoir to the cavity, and the appearance of the obtained molded product may be significantly impaired.

Therefore, according to the method of the present invention, as shown in FIG. 5, after placing the fiber reinforcement on the lower mold 2, and placing the cooling plate 17 on the bottom 11 of the liquid reservoir 12, Upper mold 1
The lower mold 2 and the lower mold 2 are clamped together, and thereafter, in the same manner as described above, after the liquid resin is injected into the liquid reservoir 12 by the RIM injection machine 9, compressed gas is injected into the liquid reservoir, and the liquid resin is It is preferable to inject it into the cavity 3 through the flow path 10 to impregnate the liquid resin into the fiber reinforcement, and then cure the liquid resin integrally with the fiber reinforcement.

According to such a method of the present invention, the liquid resin in the liquid reservoir is cooled directly by the gold 17 to ensure that the temperature of the resin in the liquid reservoir is lower than that in the cavity. Therefore, the resin in the liquid reservoir can be held in a liquid state or at least having fluidity, and the resin in the cavity can be cured more quickly than the resin in the liquid reservoir. By sending the resin remaining in the reservoir to the cavity by compressed air, it is possible to surely and effectively correct the shrinkage of the molded product.

Further, according to the present invention, the mold portion 15 constituting the liquid reservoir is thus formed by using the chill.
Although the temperature of is lower than the mold part that constitutes the cavity,
However, by maintaining a higher temperature than when a chill is not used, the resin that remains in a thin layer in the liquid pool will remain in the mold after demolding the obtained molded product. Since it reaches the cleanable cured state more quickly, this can shorten the demolding time.

The chill 17 has a three-dimensional shape similar to the three-dimensional shape or space shape of the liquid reservoir 12, and reduces the gap 18 between the outer peripheral surface of the chill 17 and the wall surface of the liquid reservoir 12. That is, it is preferable to reduce the thickness of the resin remaining in the liquid reservoir. By doing so, it is possible to effectively cool the resin in the liquid reservoir, reduce heat accumulation due to the exothermic reaction of the resin in the liquid reservoir, and cure the resin in the liquid reservoir. It can be slower than the curing of the resin inside, and the shrinkage of the molded product can be effectively corrected. When the chiller is placed on the bottom of the liquid reservoir, it may be at room temperature, but may be cooled to a predetermined temperature in advance if necessary.

Further, in the apparatus of the present invention, as shown in FIG. 5, the upper mold and the lower mold form the mold portion 14 and the liquid reservoir 12 which form the cavity 3 by matching their mating surfaces. It is preferable to have an insulating groove 19 between the portion 15 and the portion 15. Thus, between the mold part 14 forming the cavity and the mold part 15 forming the liquid reservoir, preferably, the flow path is sandwiched between the upper mold and the lower mold, or if the mold permits, the flow path is formed. By using a device that surrounds and has adiabatic groove 19, the shrinkage of the molded article can be more effectively corrected.

That is, according to such an apparatus, since the mold part forming the cavity and the mold part forming the liquid reservoir are substantially shut off from each other in temperature, each mold part is separated from the other mold part. Since it is less affected by temperature, each mold part can be maintained at an optimum temperature. Therefore, according to the present invention, in particular, as described above, using the device in which the heat insulating groove 19 is formed between the mold portion 14 forming the cavity and the mold portion 15 forming the liquid reservoir, as described above. After placing the fiber reinforcement on the lower mold 2 and placing the cooling metal 17 on the bottom portion 11 of the liquid reservoir 12, the upper mold 1 and the lower mold 2 are combined and clamped. Similarly,
By performing the molding process, it is possible to reliably correct the shrinkage of the molded product and shorten the demolding time. This aspect is the most preferable aspect of the present invention.

In the present invention, the resin used is not limited at all, and any of the resins known in the field of molding ordinary fiber reinforced plastic molded articles can be used. For example, unsaturated polyester resin, vinyl ester resin, epoxy resin, polyurethane resin, polyimide resin, phenol resin, silicone resin, crosslinked polyesteramide resin, crosslinked polyaminoamide resin, crosslinked epoxy-modified polyaminoamide resin, crosslinked polyetheramide resin, etc. Preferable examples include thermosetting resins.

The unsaturated polyester resin is an unsaturated alkyd obtained by a polycondensation reaction of a dibasic acid component such as phthalic anhydride, isophthalic acid, maleic anhydride and fumaric acid and a glycol component such as ethylene glycol and propylene glycol. Is a resin obtained by dissolving styrene in a vinyl monomer such as styrene and has appropriate physical properties and good moldability, and thus is generally used as a matrix for fiber-reinforced plastic molded products. Vinyl ester resins and epoxy resins obtained by modifying epoxy resins are superior in physical properties such as mechanical properties and curing shrinkage to unsaturated polyester resins, and are also used in large numbers. Most of the epoxy resins are fast-curing bisphenol A type epoxy resins. The polyurethane resin obtained by the polymerizing reaction of polyisocyanate and polyol is a matrix having a characteristic of rapid curing.

Among the above, in the present invention, for example, a crosslinked polyester obtained by reacting 2,2 '-(1,3-phenylene) bis-2-oxazoline with a dibasic acid in the presence of a catalyst. Amide resin, JP-A-63-24102
As described in Japanese Patent Publication No. 9-211, a catalyst is used for 2,2 ′-(1,3-phenylene) bis-2-oxazoline and a diamine compound such as 4,4′-methylenebisaniline or diaminodiphenylmethane. A crosslinked polyaminoamide resin obtained by reacting in the presence of, 2,2 '-(1,3-phenylene) bis-2-oxazoline and a diamine compound as described in JP-A-1-113422. Crosslinked epoxy-modified polyaminoamide resin obtained by reacting an epoxy resin in the presence of a catalyst, 2,2 '-(1,3-phenylene) bis-2-oxazoline and a compound having a phenolic hydroxyl group The crosslinked epoxy-modified polyetheramide resin and the like obtained by the reaction below are resins suitable for the molding method according to the present invention.

The resin used in the present invention may be appropriately selected as necessary according to the kind of the resin and the required properties of the fiber-reinforced plastic molded product to be obtained, a catalyst, a stabilizer, a release agent, and a coloring agent. Agents, flame retardants, fillers and the like are mixed.

Further, the resin used in the present invention may be a one-pack type, a two-pack type or a three-pack type. In the most preferred embodiment of the present invention, when a RIM injector is used, a three-pack type resin can be used, but a two-pack type resin is usually used. When using a two-pack type resin, the injection material is divided into a base resin and a curing agent, both are prepared in separate tanks, these are mixed by a mixing head, and the mixture is poured into a liquid reservoir, and then the above-mentioned. I sent it to Kabiti as I did. On the other hand, when a one-pack type resin is used, the base resin and the curing agent are prepared in advance in a tank, this mixture is poured into the liquid reservoir, and then sent to the cavity as described above.

As the fiber-reinforced material, those used in the production of ordinary fiber-reinforced plastic molded articles can be used in the present invention. Examples of such fiber reinforcing material include inorganic or metal fibers such as glass fiber, carbon fiber, quartz fiber, ceramic fiber, zirconia fiber, boron fiber, tungsten fiber, molybdenum fiber, steel fiber, beryllium fiber, and stainless steel fiber. And organic synthetic fibers such as polyamide fibers and polyester fibers. Such a fiber reinforcing material may be previously treated with a coupling agent in order to improve the adhesiveness with the resin.

Further, such a fiber reinforcing material can be used alone or in combination of two or more kinds,
Further, it can be used as a shape such as a preform, a mat, a cloth, or a combination thereof. In the present invention, the fiber content in the fiber-reinforced plastic molded product is not particularly limited because it depends on the viscosity of the resin material used, the type of the fiber reinforcement, the required characteristics of the molded product, and the like. , Usually in the range of 5 to 80% by weight, preferably 20 to 70% by weight.

The method of the present invention can be particularly preferably used for efficiently producing a fiber-reinforced plastic molded article of a fast-curing resin.

The molding pressure is usually in the range of 0.5 to ¹⁰ kg / cm ² , and the cycle time is usually 30 seconds to 30 seconds.
It is in the range of minutes. However, the present invention is not limited in molding pressure and cycle time, and these are
It is appropriately set depending on the resin to be used, the catalyst, the fiber reinforcing material, the size of the target molded article, and the like.

Next, FIG. 6 is a cross-sectional view showing an example of the fiber-reinforced plastic molded product 20 molded by the method of the present invention. This molded article is formed by coating the core material 21 with a fiber reinforced plastic layer 22, and as an example, for example, a lightweight core material made of hard urethane foam is coated with a blade made of carbon fiber, A molded product obtained by impregnating and curing a resin can be exemplified. Of course, the present invention is not limited by the obtained molded product.

Although the molding apparatus using the flash mold has been described above, a positive mold may be used as the mold depending on the shape of the molded product. Further, any of a mold, an aluminum mold, an electric mold, a resin mold and the like may be used.

The fiber-reinforced plastic molded product obtained by the method of the present invention is suitably used for various purposes. For example, specific examples of the product include, for example, tennis rackets, badminton rackets, golf heads and oars. , Softball and softball butts, bicycle frames, archery bows and other sports / registry items, wheelchair frames and other health care products, pump casings, equipment wings and gears. , And various industrial products such as end plates.

[0049]

As described above, according to the method of the present invention,
When injecting the liquid resin into the mold, the liquid resin is temporarily stored in the liquid reservoir, the resin in the liquid reservoir is pressurized with compressed gas, and the liquid resin is injected into the cavity. And the pressure required to impregnate the fibers with the resin can be reduced, and thus the resin foam having relatively low strength can be used as the core material of the reinforcing material. Further, by reducing the flow rate of the resin in the mold, it is possible to prevent the occurrence of voids on the surface of the molded product.

In particular, in order to inject the liquid resin into the mold,
By using the RIM injector, it is possible to shorten the molding cycle and save labor, which is an advantage of the S-RIM method. Further, according to the method of the present invention, the liquid resin is injected into the cavity while being pressurized by the compressed gas, and the pressurization is continued thereafter to correct the shrinkage accompanying the curing of the liquid resin. Therefore, it is possible to prevent the occurrence of sink marks, which is a drawback of the S-RIM method. Further, since the pressure required for molding can be reduced, a heavy mold is not required, and a light structure mold used in the RI method or VARI method can be preferably used.

In particular, according to the present invention, by using a device in which a heat insulating groove is formed between the mold part forming the cavity and the mold part forming the liquid reservoir, the fiber reinforcement is placed on the lower mold. , After placing a cold metal on the bottom of the liquid reservoir, clamp the upper mold and lower mold together, and even after injecting the liquid resin into the cavity from the liquid reservoir, the liquid resin remains in the liquid reservoir and the flow path. Then, the liquid resin is continuously pressurized with compressed gas, and the shrinkage of the molded product is reliably corrected by sending the resin to the cavity according to the shrinkage due to the curing of the resin in the cavity, so that the appearance can be corrected. An excellent and homogeneous molded product can be produced in a short demolding time.

In particular, the method of the present invention is suitable for producing a relatively small fiber-reinforced plastic molded product which does not require a long time to inject the resin in the liquid reservoir into the cavity.

[0053]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

Example 1 2,2 '-(1,3-phenylene) bis-2-oxazoline 5.
7 kg and 2.3 kg of 4,4'-methylenebisaniline were weighed and dry-mixed, which was placed in a tank for liquid A heated to about 130 ° C of the RIM injector, and 4,4'- After weighing 6 kg of'-methylenebisaniline and 0.45 kg of octyl bromide, they were dry-mixed, charged into a tank for liquid B heated to about 130 ° C. of a RIM injector, and stirred respectively. After melting, the liquid temperature of both liquid A and liquid B is 130.
The temperature was adjusted so as to be ℃. The viscosities of solutions A and B at 130 ° C. were each about 8 centipoise (B type viscometer).

The mold as shown in FIG. 4 is attached to a downward-pressing hydraulic press, and the temperature of the mold is 150 ° C. for the mold part constituting the cavity and 130 for the mold part constituting the liquid reservoir and the flow path.
After the temperature was set to 0 ° C., the fiber reinforced material having the core material as shown in FIG. 6 was placed on the cavity of the lower mold, and then the upper mold was lowered and clamped. The fiber reinforced material is a core material made of hard urethane foam and having a specific gravity of about 0.2, which is covered with a blade woven of carbon fiber and has a shape that matches the cavity. The distance from the wall is 4 mm.

Next, the valve of the pressure reducing hole of the mold was opened to reduce the pressure inside the mold to about 20 mmHg, after which the valve was closed and the inside of the mold was kept at reduced pressure. Next, the liquid resin prepared in the RIM injection machine was injected into the liquid reservoir through the injection hole so that a space remained above the liquid reservoir. Here, the injection conditions of the liquid resin into the liquid reservoir are that the discharge pressures of liquid A and liquid B are both 15 to 18 kgf /
cm ² , the mixing ratio (weight ratio) of A liquid / B liquid is 80 / 21.5,
The discharge rate of the mixed liquid of the liquid A and the liquid B was set to 200 g / sec.

Thereafter, the valve of the compressed air introducing hole is opened, compressed air having a pressure of about 2 kgf / cm ² is added to the liquid resin in the liquid reservoir, and the liquid resin is injected into the cavity through the flow path. ,
The fiber reinforcement was impregnated. The injection of the liquid resin into the cavity was almost completed in about 50 seconds after starting the pressurization of the liquid resin with the compressed air. Even after this, the pressure in the mold by the compressed air was continued to allow the liquid resin to remain below the liquid reservoir and in the flow path so that the shrinkage due to the curing of the liquid resin was replenished into the cavity.

Six minutes after the injection of the liquid resin into the cavity was started, the upper and lower molds were opened and the molded product was taken out of the mold. There were no molding defects such as voids and sink marks on the surface of the obtained molded product. The thickness of the fiber-reinforced plastic layer of the molded product was about 4 mm, and the ratio of carbon fiber in the fiber-reinforced plastic layer was about 50% by volume. RI in Table 1
The operating conditions of the M injector and the main molding data are shown.

COMPARATIVE EXAMPLE 1 A mold as shown in FIG. 1 was attached to a lower press type hydraulic press, the temperature of the mold was set to 150 ° C., and the same fiber reinforcing material as in Example 1 was placed on the cavity of the lower mold. The upper mold was lowered and the mold was clamped. After the pressure inside the cavity was reduced in the same manner as in Example 1, the liquid resin was injected into the cavity from the RIM injection machine. During the injection of this resin, the injection pressure is up to about 60 kgf /
needed cm ² .

Six minutes after starting the injection of the liquid resin, the upper and lower molds were opened and the molded product was taken out of the mold. Many voids were generated on the surface of the obtained molded product, and the appearance of the molded product was very poor. The thickness of the fiber reinforced plastic layer of the molded product is about 5 mm, which is the designed thickness (4 mm).
It was thicker than. Table 1 shows the operating conditions of the RIM injector and the main molding data.

[0061]

[Table 1]

As shown in Table 1, according to the present invention, the liquid resin is once injected from the RIM injector into the liquid reservoir, and the liquid resin is pressurized with compressed gas and injected into the cavity.
The injection of resin into the cavity requires only a very small pressure, and the resulting molded article is therefore of good appearance. On the other hand, according to the conventional method shown in Comparative Example 1, since the liquid resin is directly injected into the cavity from the RIM injection machine, a very large injection pressure is required for that purpose, which causes the core material to shrink. As a result, the obtained molded product has a poor appearance.

Example 2 2,2 '-(1,3-phenylene) bis-2-oxazoline 5.
7 kg and 2.3 kg of 4,4'-methylenebisaniline were weighed and dry-mixed, which was placed in a tank for liquid A heated to about 130 ° C of the RIM injector, and 4,4'- After weighing 6 kg of'-methylenebisaniline and 0.45 kg of octyl bromide, they were dry-mixed, charged into a tank for liquid B heated to about 130 ° C. of a RIM injector, and stirred respectively. After melting, the liquid temperature of both liquid A and liquid B is 130.
The temperature was adjusted so as to be ℃. The viscosities of solutions A and B at 130 ° C. were each about 8 centipoise (B type viscometer).

The mold as shown in FIG. 5 is attached to a downward-pressing hydraulic press, and the mold temperature constituting the cavity is 150 ° C., and the liquid reservoir and the flow path having a truncated cone shape are formed. The mold portion to be heated was 140 ° C., and the fiber reinforced material having the core material as shown in FIG. 6 was placed on the cavity of the lower mold. Next, as shown in FIG. 5, a cold plate at room temperature was placed on the bottom of the liquid reservoir, and then the upper mold was quickly lowered and the mold was clamped. The chill used here has the shape of a truncated cone similar to the above-mentioned liquid reservoir, and has an outer diameter of about 68 mm and a height of about 20 mm of iron
55C), and the interval of the annular gap between the outer peripheral surface of the chill and the wall of the liquid reservoir was about 7 mm.

In the same manner as in Example 1, four minutes after starting the feeding of the liquid resin into the cavity, the upper and lower molds were opened,
The molded product was removed from the mold. There were no molding defects such as voids and sink marks on the surface of the obtained molded product. Also,
The thickness of the fiber reinforced plastic layer of the molded product was about 4 mm, and the proportion of carbon fibers in the fiber reinforced plastic layer was about 50% by volume.

In Example 1, when the temperature of the mold around the liquid reservoir and the flow path is set to 140 ° C. as in Example 2, the liquid resin remaining in the liquid reservoir tends to cure earlier than the resin in the cavity. However, the shrinkage of the molded product could not be sufficiently corrected. On the other hand, as in the present embodiment, by using the chill, even if the temperature of the mold around the liquid reservoir and the flow path is 140 ° C., the shrinkage of the molded product can be sufficiently corrected. It was possible to shorten the demolding time from 6 minutes to 4 minutes.

[Brief description of drawings]

FIG. 1 is a sectional view showing a molding apparatus used in a conventional S-RIM method.

FIG. 2 is a sectional view showing an example of a molding apparatus that can be suitably used for carrying out the method of the present invention.

FIG. 3 is a cross-sectional view showing another example of a molding apparatus that can be suitably used to carry out the method of the present invention.

FIG. 4 is a cross-sectional view showing still another example of a molding apparatus that can be suitably used for carrying out the method of the present invention.

FIG. 5 is a cross-sectional view showing still another example of a molding apparatus that can be suitably used for carrying out the method of the present invention.

FIG. 6 is a cross-sectional view showing an example of a fiber-reinforced plastic molded product obtained by the method of the present invention.

[Explanation of symbols]

1 ... Upper mold, 2 ... Lower mold, 3 ... Cavity, 4 ... Decompression hole, 5
... Liquid resin injection hole, 6 ... Upper mold mating surface, 7 ... Lower mold mating surface, 8 ... Packing, 9 ... RIM injector, 10 ... Flow path, 11 ... Bottom of liquid reservoir, 12 ... Liquid reservoir, 13 ... Compressed air introduction hole, 14 ... Mold part that constitutes the cavity, 15 ...
Mold part constituting the liquid reservoir, 16 ... Backing groove, 17
... Chill, 18 ... Void between the outer peripheral surface of the chill and the wall surface of the liquid reservoir, 19 ... Insulation groove, 20 ... Fiber reinforced plastic molded product, 21 ... Core material, 22 ... Fiber reinforced plastic layer.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area // B29K 105: 06

Claims (9)

[Claims] 1. A pair of molds for forming a cavity, a liquid reservoir, and a flow path for communicating these by aligning the mating surfaces of the upper mold and the lower mold are prepared, and (b) the lower mold is prepared. After placing the fiber reinforcement, the upper mold and the lower mold are combined and clamped, and (c) an amount larger than the amount required to impregnate the fiber reinforcement and smaller than the volume of the liquid reservoir. A liquid resin is injected into the liquid reservoir from an injector, and most of the liquid resin is stored in the liquid reservoir, and (d) the resin is retained in the liquid reservoir so as to have liquid or fluidity, and The resin is sent from the liquid reservoir to the cavity by pressurizing it with compressed gas to impregnate the fiber reinforcement with the resin, and then (e) cure the resin integrally with the fiber reinforcement. A method for molding a fiber-reinforced plastic, characterized by: 2. A pair of molds for forming a cavity, a liquid reservoir having a bottom part in the lower mold, and a flow path for communicating these by preparing the mating surfaces of the upper mold and the lower mold, (b) Place the fiber reinforced material on the lower mold, place a chiller on the bottom of the liquid reservoir, then clamp the upper mold and lower mold together, and (c) impregnate the fiber reinforced material. Liquid resin in an amount greater than the amount necessary to do so and less than the volume of the liquid reservoir is injected from the injector into the liquid reservoir, and most of the liquid resin is stored in the liquid reservoir, (d) the liquid The resin is sent from the liquid reservoir to the cavity by pressurizing the inside of the liquid reservoir with a compressed gas while holding the resin in the reservoir so as to have liquid or fluidity, and the resin is fed to the fiber reinforced material. Fiber reinforcement, which is characterized in that (e) liquid resin is cured integrally with the fiber reinforcement. Molding method of Rasuchitsuku. 3. A mold for forming a cavity by forming a cavity, a liquid reservoir having a bottom portion in the lower mold and a flow path for communicating these by aligning the mating surfaces of the upper mold and the lower mold. Prepare a pair of molds that have a heat insulating groove between the part and the mold part that constitutes the liquid reservoir, and (b) place the fiber reinforcement on the lower mold and place a chiller on the bottom of the liquid reservoir. Then, the upper mold and the lower mold are combined and clamped, and (c) an amount of liquid resin that is larger than the amount necessary for impregnating the fiber reinforcement and smaller than the volume of the liquid reservoir is stored in the liquid reservoir. Injected from the injection machine into the liquid reservoir, most of the liquid resin is stored in the liquid reservoir, (d) while holding the resin in the liquid reservoir so as to have liquid or fluidity, the liquid in the liquid reservoir is compressed by compressed gas. By applying pressure, the above resin is sent from the liquid reservoir to the cavity, and the resin is impregnated into the fiber reinforcement. And then (e) a method for molding a fiber-reinforced plastic, which comprises integrally curing the liquid resin and the fiber-reinforced material. 4. The method for molding a fiber-reinforced plastic according to claim 1, 2 or 3, wherein the mold is heated so that the temperature of the mold part forming the liquid reservoir is lower than the temperature of the mold part forming the cavity. 5. Molding of the fiber-reinforced plastic according to claim 1, 2, 3 or 4, wherein the upper mold and the lower mold are fitted together, the mold is decompressed, and then the liquid resin is injected into the liquid reservoir. Method. 6. Even after injecting the liquid resin into the cavity,
The liquid resin is left in the liquid reservoir and the flow path, and the liquid reservoir is continuously pressurized with a compressed gas.
The method for molding a fiber-reinforced plastic according to 2, 3, 4 or 5. 7. A pair of molds are provided which form a cavity, a liquid reservoir having a bottom portion in the lower mold, and a flow path for communicating these by aligning the mating surfaces of the upper mold and the lower mold. After the lower mold is fitted and clamped, the decompression hole for decompressing the inside of the mold and the nozzle of the mixing head of the injection machine to inject the liquid resin into the liquid reservoir of the mold thus decompressed. Liquid resin injection hole for fixing and pressurizing the liquid reservoir with compressed gas, the resin in the cavity is cured,
A compressed gas pressurizing hole for sending the liquid resin in the liquid reservoir to the cavity through the passage according to the contraction, and provided between the mold portion forming the cavity and the die portion forming the liquid reservoir. And a heat insulating groove for keeping the temperature of the mold part forming the liquid reservoir lower than the temperature of the mold part forming the cavity by thermally insulating the two mold parts. Reinforced plastic molding equipment. 8. The fiber reinforced according to claim 7, wherein a flow channel is formed horizontally along the mating surface of the upper mold and the lower mold, and the bottom of the liquid reservoir is substantially in the same plane as this flow channel. Plastic molding equipment. 9. The flow path is horizontally formed along the mating surface of the upper mold and the lower mold, and the bottom of the liquid reservoir is located at a position higher than this flow path. Fiber reinforced plastic molding equipment.