JPH0757533B2 - Method for manufacturing fiber-reinforced resin product and manufacturing mold - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced resin product and a molding die used in the method, and more particularly,
A hemispherical shell-shaped molded product such as a helmet is manufactured by the reaction injection molding method in which the unreacted raw material liquid is injected into the cavity after the fiber reinforcement is placed in the cavity, and the reaction is caused while impregnating the fiber reinforcement. It is preferably used for

[0002]

2. Description of the Related Art Conventionally, in a method for producing a fiber reinforced resin product of this type by a reaction injection molding method, as shown in FIG. 3, at least a part of a mold surface 2 of a mold 1 which forms a product surface can be formed. The flexible sheet 3 is used, and the fiber reinforcement 5 is placed in the cavity 4 surrounded by the mold surface, and then the sheet 3 is covered and fixed to the mold 1, and the sheet 3 and the mold surface 2 surround it. To form a cavity, and pressurized air is applied to the sheet 3 from the outside through the inlet 6, so that the sheet 3
The fiber reinforced material 5 disposed inside the cavity 4 is pressurized via the, and the unreacted raw material liquid is injected into the cavity from the injection port 7 to cause a reaction while impregnating the raw material liquid into the fiber reinforced material. A method has been proposed by the applicant. (Japanese Patent Application No. 2-75226)

[0003]

In the manufacturing method in which a part of the above-mentioned cavity is formed by using a flexible sheet and the sheet is pressed from the outside, the excess resin is not sufficiently discharged and a molded product is obtained. The variation in thickness and weight was extremely large.

As a method for solving the above-mentioned problems, an improved method such as depressurizing the inside of the cavity at the time of injecting the unreacted raw material liquid; prolonging the injection time; prolonging the pressurization time of the sheet is considered. Repeated experiments using these methods.

In particular, when RIM nylon or cyclopentadiene for reaction injection molding is used as the matrix resin, the reaction time of the unreacted raw material liquid is fast and the resin amount remains large relative to the amount of the fiber reinforcing material in the cavity. , That is,
Molding was completed while the excess resin was not sufficiently discharged. In that case, as shown in FIG. 4, there is a drawback that the molding is completed in a state where the resin-only portion Z is partially generated on the mold surface side, and the weight and wall thickness become unstable. This was especially noticeable when a resin having a short polymerization time was used.

The present invention solves the above-mentioned problems, and is used for a manufacturing method and a method in which a resin is uniformly penetrated into a fiber reinforced material and a resin-insufficient portion and a resin-only portion are not produced. The purpose is to provide a mold.

[0007]

In order to achieve the above object, the present invention provides a method in which a fiber reinforcement is placed in advance in a mold,
In a method for producing a fiber-reinforced resin product, in which an unreacted raw material liquid is injected into a mold and a reaction is caused while the fiber-reinforced material is impregnated in the mold to mold the fiber-reinforced resin product, After arranging, the flexible sheet forming a part of the cavity of the mold is pressed from the outside to pressurize the fiber reinforced material arranged inside the cavity through the sheet, while not applying the pressure. The reaction raw material liquid is injected into the cavity, and the excess injected raw material liquid is discharged into the resin reservoir through the split surface provided on the mold surface of the mold that forms the cavity, so that the required wall thickness and weight are obtained. The present invention provides a method for producing a fiber-reinforced resin product characterized by the above.

As the above-mentioned sheet, any sheet having flexibility may be used, and nylon, cellophane, rubber, polyester, polyetherketone, etc. may be used.
Silicone rubber is most preferable in consideration of polymerizability, heat resistance, strength and the like. As the pressure medium added to the inside of the cavity via the flexible sheet, an isotropic pressure medium such as gas such as compressed air or liquid is used.

The pressure applied through the sheet is a primary pressure applied before and during the injection of the raw material liquid and a secondary pressure applied after the injection of the raw material liquid until the solidification of the raw material liquid is completed. It is preferable to set the secondary pressure to be higher than the primary pressure and the raw material liquid injection pressure in stages.

Particularly, the primary pressure is P1 and the secondary pressure is P
2. If the injection pressure of the unreacted raw material liquid is Q, it is most preferable to set the following three formulas to be satisfied. P1 ≦ Q, 1.2 × P1 <P2, Q <P2

It is also effective to depressurize the inside of the cavity in which the fiber reinforcing material is placed, in consideration of the resin permeability.

In the present invention, in particular, in order to sufficiently permeate the resin into a portion having poor resin permeability, in the fiber reinforcing material layer, along the sheet surface and / or the mold surface forming the cavity, It is characterized in that a fiber layer having a small volume ratio of fibers is arranged. As the fibers having a small volume ratio, the glass, carbon, steel, non-woven fabric of organic fibers, mats, and the like are preferably used. The main fiber layers other than the fiber layers arranged along the sheet surface and the mold surface include carbon fibers in the form of continuous fibers or long fibers, glass fibers, aramid fibers, silicon carbide fibers, steel fibers, amorphous metal fibers, organic fibers. And / or a mixture thereof is preferably used.

Further, in the present invention, as described above, a split surface is provided on the mold surface of the mold which is not on the sheet side, and a resin reservoir is arranged in a portion communicating with the inside of the cavity on the split surface. The excess resin is pushed out and discharged to the resin reservoir.

Excess resin for the fiber reinforced material is discharged from the split surface provided on the mold surface for the following reason. That is, in the case where a point-like discharge port that opens to the cavity is provided, if the periphery of the discharge port is first pressurized by the secondary pressure and reaches P2, the excess resin is removed from the cavity in the portion other than the discharge port. Will be left inside. Therefore, it is conceivable to increase the number of dot-shaped outlets, but in that case, it becomes difficult to release the molded product from the mold. On the other hand, as described above, when the split surface is provided on the mold surface of the mold and the resin is discharged from the split surface to the resin reservoir, unless the inside of the resin reservoir becomes equal to or higher than the secondary pressure P2, Emission can be continued.

The split surface must be formed so as not to undercut. When the tip of the split surface that opens to the cavity and the internal position of the split surface are provided, the resin reservoir may be communicated by a film or groove that is thicker than the burr thickness. May be

In the relationship between the volume V of the resin reservoir, the design volume V1 occupied by the resin of the molded product, and the volume V2 of the unreacted raw material liquid injected into the cavity, a sufficient amount of resin is required to improve the resin penetration. It is preferable to inject, and therefore V2> V1 and V> V2-V1 are preferable in order to have an effect as a resin reservoir.

As the resin used for the above-mentioned molding, nylon, cyclopentadiene, epoxy, urethane, polyester, polyesteramide or the like capable of reaction injection molding (RIM) or resin transfer molding (RTM) is used. Considering the impact resistance, nylon and cyclopentadiene are preferable. For example, in the case of RIM nylon, it is molded by a monomer casting method in which molten lactams containing a polymerization catalyst and a polymerization initiator are injected into a mold, and the polyamide is polymerized by heating.

The ω-lactams which are the above-mentioned monomers include α-pyrrolidone, α-piperidone, ω-enanthlactam, ε-caprolactam, ω-caprylolactam,
ω-pelargonolactam, ω-decanolactam, ω-undecanolactam, ω-laurolactam, c-alkyl-substituted-ω-lactams thereof, and mixtures of two or more kinds of these ω-lactams. Also,
The ω-lactam can optionally contain an improving component (soft component). The soft component is a compound having a functional group that reacts with the initiator used in the molecule and has a low Tg, and a polyether having a normal functional group, liquid polybutadiene, or the like is used.

Commercially available raw materials used as the above-mentioned ω-lactams include UBE nylon (U manufactured by Ube Industries, Ltd.).
X-21) etc. It is composed of an A component consisting of an alkali catalyst and caprolactam, a prepolymer containing a soft component and a B component consisting of caprolactam.

As the above-mentioned polymerization catalyst, sodium hydride is preferable, but other known .omega.-lactam polymerization catalysts such as sodium, potassium and lithium hydride can be used. The amount added is 0 for ω-lactam.
The range of 1-0.5 mol% is preferable.

As the polymerization initiator (activator), N-
Acetyl-ε-caprolactam is used, but other triallyl isocyanurates, N-substituted ethyleneimine derivatives, 1.1′-carbonylbisaziridine, oxazoline derivatives, 2- (N-phenylbenzimidoyl) acetanilide, 2- Compounds such as (N-phenylbenzimidoyl) acetanilide, 2-N-morpholino-cyclohexene-1.3-dicarboxanilide and known isocyanates and carbodiimides can be used. The amount of the polymerization initiator added is preferably within the range of 0.05 to 1.0 mol% with respect to the amount of ω-lactam.

When a cyclopentadiene resin is used as the matrix resin, dicyclopentadiene may be used as the polymerizable monomer for the cyclopentadiene resin.
Dihydrodicyclopentadiene, tricyclopentadiene, tetracyclopentadiene, cyclopentadiene-
A methylcyclopentadiene co-duplex or the like is used.

As the polymerization catalyst for the cyclopentadiene resin, halogen compounds such as tungsten, molybdenum and tantalum, oxyhalides, oxides, organic ammonium salts and the like are preferably used. As the polymerization initiator, organometallic compounds centered on alkylated metals of metals of groups I to III of the periodic table, oxygen-containing compounds such as alcohols and phenols are preferably used.

Further, since the polymerization reaction of the solution containing the above-mentioned polymerization catalyst and activator (polymerization initiator) is initiated very quickly, curing may occur before the solution sufficiently flows into the molding die. The monoether and / or monoester of a glycol compound selected from alkylene glycol or polyalkylene glycol is preferably used as the activity modifier. When injecting into the mold, the mold temperature is usually set in the range of 40 to 130 ° C.
It is preferable to carry out the polymerization reaction for 5 minutes.

The resin used in the present production method is not limited to the above polyamide resin (nylon) or cyclopentadiene resin, but may be a resin used in so-called reaction injection molding (RIM) or resin transfer molding (RTM), such as epoxy resin. Resins, acrylic resins, polyester resins, urethane resins, crosslinked polyesteramides, etc. are preferably used.

The present invention also provides a mold for use in the above-mentioned manufacturing method, wherein the mold is provided with a cavity on the mold surface of the mold and a fiber reinforcing material is disposed in the mold surface. Is formed by surrounding it with a flexible sheet that is fixed to the mold, and is provided with a means for externally pressing the flexible sheet, and the mold is provided with a split surface that communicates with the inside of the cavity. A surplus resin reservoir is provided on a part of the surface, and an injection port to the cavity is provided between the flexible sheet and the fiber reinforced material at a position where the unreacted raw material liquid is injected.

The manufacturing method according to the present invention is particularly suitable for use in manufacturing a hemispherical shell-shaped molded article such as a helmet. In that case, the mold surface of the mold is recessed into a hemispherical shape. In addition, the flexible sheet is pressed along the inner peripheral surface of the mold surface to form a cavity so that the molded product has a hemispherical shell shape.

As described above, in the mold according to the present invention, since a part of the mold surface is formed by the sheet, it is sufficient that the mold surface has only the mold surface that defines only one surface of the product to be molded. . Therefore, care is taken not to undercut the outer split surface of the product, and there is no need to worry about undercut because the inner surface of the product surface is formed of a flexible sheet.

[0029]

According to the above-described manufacturing method of the present invention, since the surplus resin is discharged from the split surface provided on the mold surface, the molding can be completed in a state where the resin layer is partially left. Can be prevented and the weight and wall thickness can be stabilized. Further, since the raw material liquid is injected to the portion where the resin is difficult to penetrate and the fiber reinforcing material having a small volume ratio of the fibers is arranged, it is possible to prevent the portion where the resin does not penetrate sufficiently.

[0030]

EXAMPLE FIG. 1 shows an example of a mold according to the present invention.
The mold 10 has a lower mold 11 having a mold surface 12 that is recessed in a hemispherical shape with an upper opening. On the upper surface of the lower mold 11,
After arranging the fiber reinforcement 13 in the mold surface 12, the flexible sheet 14 is covered, and the peripheral edge of the sheet 14 is fixed to the upper surface of the lower mold 11 with a fastener (not shown). That is,
The sheet 14 constitutes an upper mold of a normal mold, and the cavity 14 is formed by the sheet 14 and the lower mold surface 12.
Is formed.

In the lower die 11 of the mold, an injection port 20 for the unreacted raw material liquid that opens at the die surface 12 is provided at the lowermost position of the die surface 12.
Is provided. A split surface 17 is formed at an intermediate position between the upper end and the lower end. That is, the lower mold 11 is replaced with the lower first mold 1
1a and the upper second mold 11b are divided, and the first mold 11 is divided.
A resin reservoir 18 is formed at the joint between a and the second die 11b, and the resin reservoir 18 communicates with a discharge passage port 19.
A resin reservoir 16 communicating with the cavity 15 is provided on the upper end surface of the first die 11a. The resin reservoir 16 does not communicate with the outside of the mold and serves as a resin reservoir. However, when there is no excess resin, it is for containing voids and bares localized at the end of the molded product. This resin reservoir 16 is used as a sheet
The spacer 25 is provided so as not to apply pressure. It should be noted that the resin reservoir 16 and the discharge passage 19 are connected to the spacer 25 and the first mold 11
It may be installed between a and.

A groove 17a thicker than the thickness of the burr is formed between the resin reservoir 18 and the inner end position of the split surface 17 facing the cavity 15. The groove 17a may be a burr surface having a thickness that is only the normal burr thickness. The discharge passage port 19 communicates with the resin reservoir 18 as described above. Also,
It communicates with the lowermost position of the mold surface 12 and is discharged from the injection port 20 to form a discharge passage.

A pressure holding plate 21 is fixed to the die 11 together with the sheet 14 above the sheet 13, and the compressed air injection port 2 formed in the pressure holding plate 21 is disposed.
A compressed air supply pipe 23 is connected to 2 so that the sheet 14 can be pressurized with compressed air.

A hemispherical shell-shaped molded product (helmet) was molded as follows using the above-mentioned mold. Carbon cloth (W3101 made by Toho Rayon) was laminated 10 layers on the top and 6 layers other than that, and glass fiber non-woven fabric (Cumuras EPM40 made by Japan Vilene) on the side of the mold.
25) are laminated, and as shown in FIG. 2, the fiber reinforcing material 13 molded in advance in a hemispherical shell shape is arranged along the arc surface of the mold surface 12.

Then, a bendable sheet 14 made of silicon rubber (KE555U made by Shin-Etsu Chemical Co., Ltd.) having a thickness of 1.3 mm is fixed to the upper surface of the lower die 11 of the mold together with the pressure holding plate 21.

The compressed air inlet 2 for the sheet 14
Compressed air injected from 2 acts and the sheet 14 is 2 kg / c
A pressure of m ² is applied to press the portion of the sheet 14 located in the mold surface opening portion, and press the fiber reinforcing material 13 arranged along the mold surface 12. That is, as shown in FIG. 2, the mold surface 12 and the sheet 14 form a hemispherical shell-shaped cavity 15 filled with the fiber reinforcement 13.

The mold is heated to 150 ° C. and the injection port
The (exhaust passage) 20 was connected to a decompression source (not shown) to reduce the pressure in the cavity 15 to 5 mmHg.

Next, RIM nylon (UX manufactured by Ube Industries)
The monomer (-21) was melted at 90 ° C. and injected through the injection port 20. The compressed air pressure applied to the sheet 14 at that time was 0 kg / cm ² (atmospheric pressure).

After injecting a predetermined amount of RIM nylon, the injection pressure is released, and a secondary pressure is applied to the sheet 14 to pressurize it, and excess resin is collected from the split surface 17 provided on the mold surface 12 through the groove 17a. It was discharged to 18. At that time, the surplus resin was discharged from the lowermost position of the cavity 15 through the injection port (discharge passage) 20.

After the injection, the polymerization was completed within 2 minutes, the sheet 14 was removed and the mold was released, and a molded article composed of a helmet was taken out. The helmet weighed 235 g.

When the molded article made of the above helmet was cut and analyzed, no excess resin portion was found on the mold surface 12 side as shown in FIG. 4, and the thickness was uniform,
Although the improvement effect was recognized, a portion with poor resin penetration was recognized on the surface of the sheet 14 side.

As a comparative example, a helmet was molded using the conventional mold shown in FIG. 3 under the same conditions as those using the mold of the embodiment shown in FIG.

Table 1 below summarizes the performances of the helmets molded by the molds of the above-mentioned examples and comparative examples.
As shown in.

[0044]

[Table 1] Example Comparative example No excess resin on the die surface side Resin penetration into the sheet side surface Good or bad

[0045]

As is apparent from the above description, according to the present invention, a split surface is provided on the mold surface constituting the cavity and the resin is provided on the split surface so that the amount of resin with respect to the fiber can be controlled. Since the reservoir is provided and the excess resin is smoothly discharged to the resin reservoir, a portion where the excess resin is concentrated does not occur in the molded product, and the weight and wall thickness of the molded product can be stabilized.

In particular, the discharge of the surplus resin is made more effective by increasing the secondary pressure applied to the sheet after the injection is completed, and a molded product having a high fiber content and a light weight can be obtained. When the molded article is a helmet, the higher the fiber content, the higher the impact resistance and strength, and the lighter weight has the unique effect of reducing the burden on the head.

Further, in the present invention, the raw material liquid is injected between the sheet and the fiber reinforcing material, and the fiber layer in which the volume ratio of the fibers is small is arranged in the sheet side and the portion along the mold surface. The resin has a merit that it can be sufficiently permeated into a portion where resin permeation is poor, and the resin can be evenly permeated into the fiber reinforced material.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a mold according to the present invention.

FIG. 2 is a cross-sectional view showing a molding method according to the present invention for molding using the mold.

FIG. 3 is a cross-sectional view showing a conventional example of a mold using a sheet.

FIG. 4 is a cross-sectional view of a molded product for showing problems of the molded product according to the conventional example.

[Explanation of symbols]

 10 Mold 11 Lower Mold 12 Mold Surface 13 Fiber Reinforcement Material 14 Flexible Sheet 15 Cavity 17 Split Surface 18 Resin Reservoir 20 Injection Port

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // B29K 105: 06 B29L 31:48

Claims (5)

[Claims] 1. After arranging a fiber reinforcing material in a mold in advance,
In a method for producing a fiber reinforced resin product, which comprises injecting an unreacted raw material liquid into a mold and causing a reaction while impregnating the fiber reinforced material in the mold to form a fiber reinforced resin product, After arranging, the flexible sheet forming a part of the cavity of the mold is pressed from the outside to pressurize the fiber reinforced material arranged inside the cavity through the sheet, while not applying the pressure. The reaction raw material liquid is injected into the cavity, and the excess injected raw material liquid is discharged into the resin reservoir through the split surface provided on the mold surface of the mold that forms the cavity, so that the required wall thickness and weight are obtained. A method for producing a fiber-reinforced resin product, characterized in that 2. The fiber reinforcing material previously arranged in the mold is characterized in that a fiber layer having a small volume ratio of fibers is arranged along a sheet surface forming a cavity and / or a mold surface. The method for producing a fiber-reinforced resin product according to claim 1. 3. A secondary pressure increasing device for pressurizing the fiber reinforced material through the sheet after the completion of injection of the unreacted raw material liquid into the mold and before the unreacted raw material liquid is reacted and solidified. The manufacturing method according to claim 1, further comprising a pressure action step. 4. A fiber-reinforced resin molded article is prepared by previously arranging a fiber-reinforced material in a cavity of a mold and then injecting an unreacted raw material liquid into the cavity to cause a reaction while impregnating the fiber-reinforced material. In a mold for manufacturing, the cavity is formed by surrounding the mold surface of a mold and a flexible sheet which is fixed to the mold after arranging a fiber reinforcement in the mold surface, and -Reinforced resin characterized in that a means for pressurizing the flexible sheet from the outside is provided, and a split surface communicating with the inside of the cavity is provided in the mold, and an excess resin reservoir is provided at a part of the split surface. Mold for manufacturing molded products. 5. The mold surface is recessed in a hemispherical shape, and the flexible sheet is pressed along the inner peripheral surface of the mold surface to form a molded product in a hemispherical shell. The mold according to claim 3, wherein the cavity is formed so as to have a shape.