JPH04201551A - Molding method of fiber reinforced composite - Google Patents

Abstract

PURPOSE:To contrive to mold a thick fiber reinforced resin layer by a method in which two curing molds are arranged, and feeding of the material for a core layer and curing process are divided into two former and latter stages, and then in former stage, the resin which forms surface layer is cured to a point immediately before gelling point, and in latter stage, said resin is perfectly cured. CONSTITUTION:This is the molding method of fiber reinforced composite in which fiber reinforcing resin layer is molded on the surrounding of a core layer 8. At least two curing molds 4, 6 are arranged in series and in the advancing direction of the molding material with reinforcing fiber 2 which is fed coincidently with the outer peripheral surface of the core 1. While curing process is divided into two stages of a first curing stage and a second curing stage, molding material is fed from both curing molds 4, 6. In the first stage, the curing degree of the resin in the surface part of molding material is stopped at gelling condition. Consequently the fiber reinforcing resin layer may be laminated stepwise to the core, whereby the composite with thick fiber reinforced resin layer may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for molding a fiber-reinforced composite comprising a core layer and a fiber-reinforced resin layer surrounding the core layer.

(Prior Art) Conventionally, a method is known in which a so-called pultrusion method is used to continuously produce a fiber-reinforced composite comprising a core layer and a covering layer surrounding the core layer. For example, JP-A-52-5967
Publication No. 6 discloses that while a rod-shaped body, glass fiber, etc. are continuously fed through an entrance of one of the molding passages in the mold, a thermosetting resin is poured from an opening provided in the molding passage near the entrance of the mold. A composite molding technique is disclosed in which the core layer is injected and heated and cured in a mold to integrate the core layer and a covering layer made of glass fiber reinforced resin disposed around the core layer.

(Problems to be Solved by the Invention) However, in the method for forming fiber reinforced composites using the conventional pultrusion method described above, the material forming the covering layer is The closer the resin is to the layer, the worse the heat conduction within the mold and the more difficult it is to harden. If this is done forcibly, the resin will not form a network structure, and the resin will not form a network structure.
Therefore, the adhesive strength between the core material layer and the coating layer becomes poor, and on the other hand, the molding speed cannot be increased.

Therefore, it is physically difficult to form a thick coating layer, that is, a fiber-reinforced resin layer, and there is a problem in that there are restrictions on the uses of the molded fiber-reinforced composite.

The present invention has been made to overcome the drawbacks of the prior art as described above.

(Means for Solving the Problems) The present invention provides a method for molding a composite consisting of a core material layer and a fiber reinforced resin layer enclosing the core material layer. The curing molds are arranged in series to divide the curing process into two stages, a first curing stage and a second curing stage, and the molding material is fed from either of the curing molds. The gist of the present invention is to provide a method for molding a fiber-reinforced composite, which is characterized in that the degree of hardening of the resin in the surface layer of the molding material remains in a gelatinous state during the curing step.

That is, the aim of the molding method of the present invention is to arrange two or more curing molds and divide the feeding of material into the core material layer and the curing process into two stages: front and rear, and in the previous stage, the degree of hardening is determined to form the surface layer. The resin is heated to just before the gelation point, and the next step is to completely cure it, ultimately forming a thick fiber-reinforced resin layer.

In the first curing stage, the reason why the degree of hardening of the resin in the surface layer of the molding material is kept at a gel state is that pultrusion molding is not possible before gelation, and on the other hand, after gelation, FRP Since it contains a mold release agent, it bleeds easily (second coating cannot be applied).

Examples of reinforcing fibers used in the fiber-reinforced resin layer of the present invention include rovings such as glass fibers, carbon fibers, and organic fibers, chopped strand mats, cross mats, and laminated mats. or both can be used together.

The types of resin used in the fiber reinforced resin layer of the present invention include:
Examples include thermosetting resins such as unsaturated polyester resins and epoxy resins.

Examples of the core material used in the core material layer of the present invention include fiber-reinforced composites, or those molded from metals such as steel, copper, and aluminium, and the shape thereof can be appropriately selected depending on the use of the composite. .

In the present invention, in order to mold using the above-mentioned material, first, the curing mold placed in the first curing stage has a cylindrical cavity (hereinafter referred to as "molding passage") through which the molding material passes. The diameter of the molding material is usually 0.5 to 10 mm larger than that of the molding material. Further, the set temperature of the curing mold is usually 70 to 120°C depending on the length of the curing mold, drawing speed, etc.

Then, while passing the core material through the molding passage of the hardening mold prepared in this way, a reinforcing fiber impregnated with resin is coated in front of the entrance of the molding passage, so that the total molding material is 0.5 to 5.
The resin is pulled out at a speed of m/min and cured until the impregnated resin becomes a gel.

Next, the hardening mold placed in the second hardening stage has a diameter of its molding passage 0.5 smaller than that of the molding material coming out of the hardening mold placed in the first hardening stage. ~10mm
The size shall be such that large diameter objects can pass through. In addition, the set temperature of the curing mold depends on the length of the curing mold, the drawing speed, etc., similarly to the first curing mold, and is usually 120 to iso'c.
shall be.

Then, while passing the molding material coming out of the first curing mold through the molding passage of the curing mold prepared in this way, coating reinforcing fibers impregnated with resin in front of the entrance of the molding passage, At this stage, the entire molding material is pulled out at a speed that allows the resin in the molding material to be almost completely cured.

In the present invention, the number of curing molds to be placed in the first or second curing stage is not necessarily limited to one, and a plurality of curing molds may be installed as appropriate. It must be noted that the mold and the mold for the second curing stage are naturally different in their set temperature, molding passage diameter, etc. For example, an apparatus in which a plurality of curing molds for a first curing stage are successively arranged, and then a plurality of curing molds for a second curing stage are arranged successively, or a first curing mold Examples include an apparatus in which a hardening mold and a second hardening mold are arranged alternately.

(Function) The method for molding a fiber-reinforced composite of the present invention involves the step of molding a composite consisting of a core material layer and a fiber-reinforced resin layer enveloping the core material layer, in which two or more hardened fibers are The molds are arranged in series and the curing process is divided into two stages, a first curing stage and a second curing stage, and the molding material is fed from either of the curing molds. In the curing stage, we decided to keep the degree of hardening of the resin in the surface layer of the molding material at a gel state, so we added fibers in several layers in stages around the core material or to the already hardened fiber reinforced resin layer. It becomes possible to laminate reinforced resin layers.

(Example) Examples of the method of the present invention will be described in detail below with reference to the drawings.

Materials used ■, Resin = 150°C curing unsaturated polyester resin ■,
Fiber: Roving (manufactured by Asahi Fiber Co., Ltd., #4550) and glass mat (manufactured by Asahi Fiber Co., Ltd., #450) ■ Core material: Made of aluminum alloy, rod molding with a thickness of 10 mmφ Figure 1 shows the molding method used in the present invention. FIG. 1 is a schematic diagram of a preferred device, in which 1 is a core material that is continuously fed in the direction of the arrow. Reference numeral 2 denotes reinforcing fibers that are fed along the outer circumferential surface of the core material 1 in accordance with the movement of the core material before a mold described later, and are unwound by a pair of rolls 3 arranged above and below.

Reference numeral 4 denotes a first hardening mold, and a molding passage 5 is provided therein. Reference numeral 6 denotes a second curing mold disposed in front of the first curing mold 4, and a molding passage 7 similarly extends in the axial direction inside the second curing mold.

Therefore, the diameter of the molding passage of the first hardening mold 4 is 36 mm, and 5 glass rovings are placed around the core material as the molding material.
00 pieces, the same (three layers of glass mats were fed on the top surface of the glass rovings. Also, the diameter of the molding passage of the second hardening mold 6 was 50 mm, and the glass rovings were used as the molding material in the first hardening mold. 420 pieces of glass mat were fed around the molding material coming out of the glass roving so that two layers of glass mat were stacked on the top surface of the glass roving.The set temperature of the first curing mold 4 was set at 100°C. 6 was set at 150° C., and pultrusion was performed at a speed of 2 m/min using a drawing machine (not shown).

As a result, a fiber reinforced composite as shown in FIG. 2 was obtained.

In the figure, 8 is a core material layer, and its thickness is 120 mm, and a fiber reinforced resin layer 8 is formed around the core material layer 8, and its thickness is 6 to 7 mm. .

(Effect) The method for molding the fiber reinforced composite of the present invention involves arranging two or more curing molds in series in the direction of progress of the molding material, and dividing the curing process into a first curing stage and a second curing stage. The molding material is fed into both curing molds, and in the first curing stage, the degree of curing of the resin in the surface layer of the molding material is kept at a gel state. Therefore, it has become possible to stack a number of fiber-reinforced resin layers in stages around the core material or on the already hardened fiber-reinforced resin layer.

Therefore, it is now possible to obtain a composite having a thick fiber-reinforced resin layer, which could not be obtained with the conventional technology. The range of applications has been expanded.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus suitable for use in the molding method of the present invention;
FIG. 2 is an enlarged sectional view showing a fiber reinforced composite obtained by the above molding method. L... Core material, 2... Glass roving, 4... First hardening mold, 5 and 7... Molding material passage, 6... Second hardening mold, 8... Core material layer, 9... Fiber reinforced resin layer.

Claims (1)

[Claims] 1. In a method for molding a composite consisting of a core material layer and a fiber reinforced resin layer encasing it, two or more curing molds are arranged in series in the direction of movement of the molding material, and the curing The process is divided into two stages, a first curing stage and a second curing stage, and the molding material is fed from either of the curing molds, and in the first curing stage, the surface layer of the molding material is A method for molding a fiber-reinforced composite, characterized by keeping the degree of curing of a certain resin in a gel state.