JPH01237124A - Molding method for fiber reinforced resin molded product - Google Patents

Abstract

PURPOSE:To apply resin between fibers uniformly and reduce the generation and residue of foams by intermittently pressure injecting resin and infiltrating the resin between fibers when the resin is pressure injected from a gate into a cavity and a fiber reinforced resin molded product is molded. CONSTITUTION:Uncured thermoset resin liquid such as polyester resin or the like blended with a curing agent is pressure injected from a gate 5 into a cavity 7 at an interval of given volume by the operation of a valve or the like. Resin 8 injected into the cavity 7 fills the cavity around the gate partially. The resin B stopped to be injected in said state loses fluidity, and part of the resin is infiltrated and absorbed into a glass fiber cloth 2 by the capillarity generated in the spaces between glass fibers. When the resin is pressure injected again, the filling area of resin the cavity 7 by said resin 8a is increased, and infiltration of resin is generated at the time of stopping injection. Such an injection is repeated many times until the resin is filled in the whole of the cavity, and compression by a mold is carried out finally.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention involves inserting fiber cloth, mat, etc. into the cavity of a mold, and injecting resin into the cavity under pressure to mold a fiber-reinforced resin molded product. It is about the method.

[Prior art] Generally, this type of molding method involves inserting a cloth or mat made of glass fiber, organic fiber, inorganic fiber, etc. along the mold surface of one of a pair of mating molds, then closing the mold. After the mold is clamped, the pressure in the cavity is reduced, and resin is injected under pressure while maintaining this state. The resin used for this molding is an uncured thermosetting resin liquid such as polyester resin, polyurethane resin, epoxy resin, epoxy acrylate resin, and unsaturated acrylate resin that has been blended with a curing agent in advance. It becomes a reinforced resin molded product.

[Problems to be Solved by the Invention] In the above-mentioned conventional method, the penetration of the resin into the Ti fibers and the defoaming are performed using the suction force in the cavity due to pressurizing force and reduced pressure. The resin injected into the cavity flows through spaces with low flow resistance, such as between the fiber cloth and the cavity wall, and the gaps between laminated fiber cloth, etc., and fills those spaces. After that, it penetrates into fiber cloth etc.

Therefore, even if a gate position or depressurization position is set for the cavity so that the resin flows in one direction while penetrating between the fibers, the resin will penetrate from around the fiber cloth after filling the space. Also, since the air between the fibers whose surroundings were first closed by the resin has no other place to flow out, this acts as a resistance and prevents the resin from permeating through pressure injection, resulting in uneven permeation and the formation of air bubbles. It causes the occurrence.

The inventors of the present invention have conducted various studies on the penetration of resin between fibers, and have discovered that the most uniform molded product can be obtained by performing penetration using capillary phenomenon.

Therefore, an object of the present invention is to provide a new molding method that allows resin injected into a cavity under pressure to be uniformly impregnated between fibers by capillary action, and that generates and leaves very few air bubbles.

[Means for Solving the Problems] This invention according to the above-mentioned object is to insert a fiber cloth, a mat, etc. into a cavity of a mold, and to inject resin into the cavity under pressure from a gate. The conventional problem is solved by performing the injection intermittently or with intermittent injection and applying ultrasonic imaging to the resin injected into the cavity to allow the resin to penetrate between the fibers.

[Operation] In the above method, the liquid resin injected into the cavity under pressure first fills a part of the gap between the cavity and the fiber cloth, and then a part of the resin penetrates into the gap between the fibers by capillary action. do. By repeating such partial injection and infiltration of the resin, a molded article is produced in which the resin evenly infiltrates the fiber cloth, etc.

[Example] In the figure, 1 is a long insert material, which is made of a core material 2 and a glass fiber cloth 3 wound in multiple layers to form a flat shape.

A mold 4 is composed of a pair of mating molds, and a gate 5 is provided in the center of the mold 4a.

Further, pressure reducing ports 6 are provided on both sides of the other mold 4b.

The insert material 1 is inserted into the cavity 7 along with the mold 4b, and is fixed by commonly used means so as not to move due to the injection pressure.

After the mold is closed and clamped, an uncured thermosetting resin liquid such as polyester resin containing a hardening agent is poured into the mold.
Gate 5 is opened at fixed intervals of s by valve operation etc.
Pressure is injected into the cavity 7 from below.

As shown in FIG. 2, the resin 8 injected into the cavity 7 partially fills the cavity around the gate. The resin 8 whose injection is stopped in this state loses fluidity, and a portion of the resin permeates and is absorbed into the glass fiber cloth 2 due to capillary action occurring in the gaps between the glass fibers. Therefore, the amount of resin 8 that partially fills the cavity space is temporarily reduced.

When the resin is again injected under pressure, the resin 8a increases the filling area of the resin in the cavity 7, as shown in FIG. 3, and when the injection is stopped, the resin permeates as described above. This injection is repeated several times until the resin is filled throughout the cavity, and is finally compressed by a mold.

The embodiment shown in FIG. 4 is a case where injection is carried out simultaneously from multiple locations, and three
A mold 1 is used in which gates 5a, 5b, and 5c are arranged in parallel at regular intervals.

Molding is carried out by intermittently injecting a certain amount of resin into the cavity 7 under pressure from each gate at the same time.

The resins 8, 8a from the gates 5a, 5b, 5c are distributed concentrically around the respective gate positions into the cavity 7.
One molded product is completed by repeatedly filling the fibers and penetrating between the fibers until they touch each other, and the filling covers the entire cavity.

Simultaneous injection from multiple gates requires shorter injection time compared to injection from the - point, and the flow resistance due to the previously injected resin is also considerable, so even if it is a long one, there will be no unpenetrated parts. Molding can be easily performed without generating bubbles.

Also, t! of the insert material 1 above! Depending on the composition of the miscellaneous cloth 3, a vacuum pump may be connected to the pressure reducing port 6 to reduce the internal pressure of the cavity 7, and the resin may be injected under pressure under suction, or the mold 1 may be subjected to ultrasonic imaging. The injected resin in the injected cavity is connected to a motive force, and the injected resin is moved to promote penetration of the resin between the fibers.

C Effect of the invention 1 As described above, this invention inserts an IN cloth, mat, etc. into the cavity of a mold, intermittently injects resin into the cavity under pressure from a gate, and temporarily stops the resin injection. When the resin is filled, the resin naturally penetrates between the fibers due to capillary action, so the resin flows from the gate position to the end of the cavity while repeating filling and penetration. This prevents the formation of unpenetrated areas and bubbles, which tend to occur when this method is used.

As a result, a molded product with no uneven penetration can be obtained even if the molded product is long.

Further, depending on the composition of the fiber cloth, etc., it has the advantage that it is possible to use a suction effect due to reduced pressure or to apply ultrasonic vibration to the injected resin to promote penetration.

[Brief explanation of the drawing]

The drawings show an embodiment of the method for molding a fiber-reinforced resin molded product according to the present invention. Figs. 1 to 3 are process explanatory diagrams of the first embodiment, and Fig. 4 shows the mold in the open state. Plan view,
FIG. 5 is a sectional view of another embodiment in the mold closed state, and FIG. 6 is a plan view of the mold in the mold open state. 1...Insert material 2...
Core material 3...Fiber cloth 4...
・・Mold 5.5a, 5b, 5cm・・・Gate 6・・
...Decompression port 7...Gate 8.8a...Resin patent applicant 1 person other than Nissei Plastics Co., Ltd.

Claims (4)

[Claims] (1) Insert fiber cloth, mat, etc. into the cavity of the mold, and inject resin into the cavity under pressure from the gate. When molding a fiber-reinforced resin molded product, the resin is injected under pressure intermittently. A method for molding a fiber-reinforced resin molded product, characterized by infiltrating resin between fibers. (2) Insert fiber cloth, mat, etc. into the cavity of the mold, inject resin into the cavity under pressure from the gate, and inject the resin under pressure to the specified level when molding a fiber-reinforced resin molded product. A method for molding a fiber-reinforced resin molded product, characterized by infiltrating resin between fibers simultaneously and intermittently from a plurality of gates at different intervals. (3) Item 1, in which the mold cavity is depressurized in advance;
2. A method for molding a fiber-reinforced resin molded product according to item 2. (4) The method for molding a fiber-reinforced resin molded product according to items 1 and 2, wherein ultrasonic vibrations are applied to the resin in the cavity during injection.