JPH0584756A - Production of composite molded product - Google Patents

Abstract

PURPOSE:To produce a composite molded product consisting at a least of a surface layer part composed of a resin and a core part composed of a foamed core by effectively putting the ground matter of a recovered used product to practical use. CONSTITUTION:A material for forming a surface layer part like a reinforced fiber sheet and/or a separation layer such as a fabric or a nonwoven fabric reduced in its mesh size are arranged to a mold and a mixture of a foamable resin, the ground matter of a recovered product and a liquid molding resin is put in the mold and the mold is closed to perform thermal molding to obtain a lightweight useful composite molded product having at least a surface layer composed of a resin and a core part composed of a foamed core.

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 composite molded article in consideration of recovery and reuse of used products. More specifically, a lightweight fiber reinforced resin having a foam core as its core portion (abbreviated as FRP, the same applies hereinafter) after the end of its useful life.
The present invention relates to a method for producing a similar FRP composite molded product again by collecting a composite molded product, adding a crushed product crushed into a granular or sandy state to a foamed core portion, and again.

[0002]

2. Description of the Related Art FRP composite molded products having a foam core in the core have been applied to various applications such as surfboards and turbine blades because they are excellent in lightness and toughness.

For manufacturing an FRP composite molded article having a foam core in the core, for example, the foam core of the core is molded in advance,
After wrapping this with a woven fabric as a reinforcing material, it is again inserted into a mold, and a liquid molding resin is injected to form an outer shell (JP-A-55-82612, JP-A-61-27951).
No. 7, JP-A-63-162207), or a method in which the FRP of the outer shell is molded in advance and a foaming urethane resin or the like is injected into the void in the center thereof to foam in the void. Has been.

In recent years, from the standpoint of effective utilization of resources and global environmental problems, it is desired to develop a technology for recovering and reusing wastes that cannot be easily treated, especially FRP composite molded articles whose useful life has passed. Until now, effective reuse technology has not been developed. Even if the waste is collected and reused as an FRP composite molded product, the above-mentioned method forms a new FRP composite molded product using the recovered FRP composite molded product because of problems in the molding process. As a result, the production efficiency of the molded product is low and the cost is high. Furthermore, these methods have limitations on the shape and size of the molded product that can be produced and the content of the crushed product of the composite molded product.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and produces a FRP composite molded article having a foamed core in the core, and includes a recovered foamed core of the FRP composite molded article. It is intended to provide a method capable of efficiently forming a composite molded article of any shape having a light weight and rigidity, which enables simultaneous formation of the surface layer portion composed of the liquid molding resin in one step. In addition, it is intended to provide a method that is useful for environmental problems in crushing and reusing used recovered products.

The inventors of the present invention have conducted research on a molding method capable of effectively using a pebble-like or sand-like granular material or a powdery material obtained by collecting and crushing a used product, and as a result, the inventors of the present invention have previously conducted research on a molding method. Patent application No. 90113245.6, Japanese Patent Laid-Open No. 1-3242
The inventors have found that the crushed material can be effectively utilized by utilizing the method proposed in No. 60, etc., and have reached the present invention.

[0007]

SUMMARY OF THE INVENTION According to the present invention, at least a surface layer portion molded with a liquid molding resin into a predetermined shape, a core portion formed of a foam core, and, if necessary, interposed between the surface layer portion and the core portion. In producing a composite molded article having a separation layer, the material for forming the surface layer portion and / or the expanded resin after expansion and the crushed material of the used recovered product are substantially formed in the molding die. A separating layer which does not pass through but allows liquid molding resin to pass therethrough is provided. (B) In a portion which becomes a foamed core after molding, that is, in a region surrounded by the material of (a) above, (a) a foamable resin ,
(B) The presence of crushed products and (c) liquid molding resin, (c) heating a predetermined region of the mold to a sufficiently high temperature, and / or temperature rise due to the reaction heat of the liquid molding resin. Thereby heat-foams the expandable resin to cause volume expansion, thereby pressing the surface layer forming material and / or the separation layer against the internal constraining surface of the mold, and at least a part of the liquid molding resin as required. It is characterized in that it reaches the surface layer portion, (d) cures the liquid molding resin in that state, and (e) takes out the obtained molded product from the mold, and particularly (b) above. The greatest feature of the present invention is that a crushed product of a molded product is used together with the foamable resin (a) and the liquid molding resin (c) in the step.

In the method of the present invention, a mold for molding is first prepared. This mold is appropriately selected and used from a mold, a wooden mold, a resin mold and the like according to the molding temperature. In the mold, that is, along the inner wall surface of the cavity of the mold, one or more layers of reinforcing fiber material and / or separation layer constituting the surface layer portion are provided.

Here, as the separation layer, at least a part or all of the separation layer, which has a separating function to allow the liquid molding resin to pass through without substantially passing through the crushed material and the expandable resin after thermal expansion, The rest is made of a material that does not pass the liquid molding resin.

Examples of materials capable of exhibiting the separating function of the separating layer include a fiber sheet and / or a porous sheet having a small opening. As the fibrous sheet for the separation layer, woven fabric, knitted fabric, braid, non-woven fabric, paper or the like of various natural fibers, synthetic fibers, inorganic fibers or the like is used, and the porous sheet is a sheet or film having continuous ventilation holes. For example, a foam sheet of polyurethane, polystyrene, polypropylene, or the like, or a porous membrane of polyethylene, polypropylene, polysulfone, or the like formed by a stretching, extraction or coagulation method is used. The openings are selected in a range that does not allow passage, depending on the size of the crushed material to be used, the type of foamable resin and the foamability. As the separating layer, a sheet having a small opening such as glass fiber, carbon fiber or aramid fiber, which itself has a function as a reinforcing material, can be used. In this case, the separation layer itself also serves as a reinforcing material for the surface layer portion. Further, as the separating layer, a material having elasticity can be selected so that it can be easily matched with the shape of the molded product.

The separation layer may be made of a material partially impervious to the liquid molding resin. For example, in addition to joining a part made of a material having a separating function and a material different from the material used in the part, a part of the fiber sheet and / or the porous sheet having a separating function is preliminarily coated with a resin. The opening may be sealed, if the fiber sheet can be fused by heat treatment such as polypropylene fiber, a part of the openings may be crushed by the fusion treatment, or a film or the like may be partially attached.

Instead of the above-mentioned separating layer or in addition to the separating layer, a reinforcing fiber sheet or preform having a poor separating function may be used together. In this case, the openings of the reinforcing fiber sheet or preform can be freely selected. For example, a unidirectional fiber array prepreg or a three-dimensional woven / knit preform can be used. If a separation layer is not used, these are the surface layer parts. It becomes a forming material.

The separating layer and / or the surface layer forming material (such as a reinforcing fiber sheet or preform) may be previously treated with a resin in the form of a prepreg without losing the intended function of the separating layer. As long as it is possible.

In the method of the present invention, as described above, for example, a crushed material, a foaming resin, and a liquid molding resin are required in a portion where a foam core is formed in a mold in which the separation layer is installed along the inner wall surface of the cavity. According to the above, the fourth component described below is added. When the above components are mixed and have fluidity, it is preferable that the above components be injected in advance as a mixture.

In the injection, the inside of the mold may be injected under the atmospheric pressure, but when the vacuum is applied and the mixture is injected, the mixture spreads evenly throughout the inside of the mold and is provided as necessary. The liquid resin from the mixture separated by the separation layer can enter the inside of the fibrous sheet of the separation layer to eliminate voids in the fibrous portion.

However, when the amount of the crushed material, the expandable resin, and the fourth component increases, the mixture often becomes a lump or a solid having less fluidity. In that case, the lump is opened in a mold. It can be injected in the closed state or inserted into a solid form.

The foamable resin used here has a volume which increases at least twice, preferably 3 to 6 times, and more preferably 6 times or more by heating, and is suitable for use as a liquid curable resin for molding. It does not dissolve. Further, in order that the liquid resin does not enter the foaming space portion, a material in which foaming becomes closed cells is used.

Examples of the foamable resin include curable foams such as polyurethane, phenol, polyurea, melamine and polyimide, precursors thereof, polyvinyl chloride,
Examples thereof include thermoplastic resins such as polyvinylidene chloride, polyacrylonitrile, polystyrene, polyethylene, polypropylene, PPO, polyamide, polycarbonate, PBT, and polyimide.

The foaming of the foamable resin is carried out by a foaming agent decomposition method,
Any method such as a solvent vaporization method, a chemical reaction method, or a gas mixing method can be applied. Of these, the foaming agent decomposition method and the solvent vaporization method are preferably used.

Particularly preferred as the foamable resin is
It is a heat-expandable resin particle containing a heat-expandable or foamable substance known by trade names such as "Microsphere", "Expansel", "Eslen beads" and the like. Examples of such resin particles are described in detail in the above mentioned European patent applications.

On the other hand, the crushed material used in combination with this is preferably a dried and solid material, and one which does not decompose at a temperature of at least 100 ° C. or less is preferred. Further, those that are stable at the molding temperature are preferable. Depending on the shape of the used product, a relatively large recovered product is crushed into a pebbly or sandy crushed product. The size of the crushed product is preferably such that its maximum size (maximum diameter) is smaller than the minimum thickness of the target molded product.

Examples of such recovered products include rubbers, lightweight inorganic materials, various plastics, mixtures of metals and plastics,
Examples thereof include a mixture of an inorganic substance and plastic, an FRP composite molded product, and the like, and an FRP composite molded product having a foam core in the core is particularly preferable.

In the method of the present invention, it is possible to effectively use the FRP composite molded article produced by the method of the above-mentioned European patent application, which is recovered after use and crushed, and the FRP composite molded article produced by the method of the present invention itself. It is also possible to use a crushed material recovered from

In the method of the present invention, it can be said that the use of such a crushed material is extremely important from the viewpoints of effective utilization of resources, purification of the global environment, etc., but such use is possible in the method of the present invention. That is, it has been impossible for the present inventors to predict at all.

On the other hand, as the liquid molding resin, generally known liquid molding resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin, curable dicyclopentadiene resin and non-foaming urethane resin are preferably used.

The blending ratio of the foamable resin and the liquid molding resin to the crushed product in the method of the present invention varies depending on the density of the crushed product, the density and toughness of the resulting molded product, ease of molding, etc. 30/70 to 70 in comparison
The range of / 30 is preferable.

In addition to the above three components, the mixture may further contain a non-expandable inorganic hollow particle such as silica balloon or silassul balloon or a pigment as a fourth component. As the inorganic hollow particles, those that basically do not pass through the separation layer are used.

Further, in order to increase the strength of the molded product, carbon fibers, aramid fibers, short fibers such as silicone carbide, potassium titanate, and boron, whiskers, etc. can be added, and pigments and the like can be added if necessary. You can also do it. In any case, it is appropriate to mix the components so that the density of the foamed core after molding is 0.6 g / cm ³ or less.

The amount of the above mixture to be poured or packed in the mold should be appropriately selected in consideration of the compounding ratio of the foaming resin and the volume expansion coefficient during heating.

Next, the mold is heated from the outside or the temperature is raised by the heat of curing of the liquid resin or both.
The expandable resin in the mold cavity is expanded in volume by foaming or the like.

At this time, by causing the volumetric expansion of the foamable resin while the liquid molding resin maintains fluidity, the expansion pressure of the foamable resin causes the separation layer and / or other surface layer forming material to be molded. The inner surface of the molded article is pressed against the inner constrained surface of the molded article to form an outer shape along the constrained surface, and at the same time, if there is a separating layer, the liquid molding resin penetrates into the separating layer, and a part of the liquid molding resin passes through the layer and passes through the layer. Form a layer (outer skin). Then, excess resin is collected in a storage portion of the mold or is removed from the vent, and the resin in the mold is cured to obtain a desired molded product. Curing is usually performed by heating a predetermined portion of the mold to a temperature above the curing temperature of the liquid molding resin,
In addition, post-curing may be performed depending on the type of liquid molding resin.

As described above, in the method of the present invention, the outer shape is formed by pressing the separation layer or surface layer portion forming material against the internal constraining surface of the mold by utilizing the volume expansion pressure of the foamable resin. One of the basic features is that a part of the surface layer (outer skin) is formed, and the remaining part of the core is combined with the crushed material to integrate the crushed material into the foam core and the surface layer portion.

When a separating layer is used, it is preferable that the separating layer is composed of a portion having a separating function of passing through the crushed material and the foamable resin after thermal expansion but not passing through the liquid molding resin. However, even if such a part does not constitute the whole, at least a part thereof and the rest may be made of a material that does not pass the liquid molding resin. Even if such a separation layer is used, the object of the present invention can be achieved if the liquid molding resin can spread to the surface layer portion of the entire separation layer through the portion having the separation function.

In addition to the crushed product, the expandable resin, and the liquid molding resin, inorganic hollow particles, short fibers, pigments, etc., of which volume expansion cannot be expected as described above are added as a fourth component unless the effects of the present invention are impaired. You can also do it.

[0035]

EXAMPLES The present invention will now be described in detail with reference to examples, but these are for explaining the present invention, and the present invention is not limited to these examples.

[0036]

EXAMPLE 1 This example is an example of producing a flat composite sandwich core molded article by the method of the present invention.

Vertical 360 mm, Horizontal 260 mm, Thickness 20 mm
Using a stainless steel mold for flat plate molding having a liquid passage capable of passing through the heat medium, a glass fiber plain weave cloth (a fabric weight of 200
g / m ² ) was set. Next, stretch the polyester non-woven fabric with a small opening, length 320mm, width 220
mm, thickness 10 mm, in a bag-shaped product, composite molded product consisting of epoxy resin molded surface layer and epoxy resin foam core (total density 0.4
2g / cm ³ ) finely crushed with a hammer mill, polystyrene expandable particles (“Eslen beads” HE type manufactured by Sekisui Plastics) and epoxy resin (“Epicoat” / “Epomate” 100 manufactured by Yuka Shellpoxy Co., Ltd.) A mixture of / 31 mixture) in a weight ratio of 55/40 (360 g) was added, and a bag in which the opening was sealed by heat sealing was inserted into a mold.

With the mold closed and the vent open to the atmosphere, oil at 110 ° C. was poured into the mold, and after about 45 minutes, the mold was cooled, and then the mold was opened to release the molded product. ..

The molded article has a thin epoxy resin-like skin which is free from defects such as voids, and a glass fiber reinforcement is present immediately below the skin along the skin and pressed against the foam core of the inner layer. Sushi (glass fiber volume content 42
%), And it was confirmed that a molded product (overall density 0.80 g / cm ³ ) having a composite sandwich core in which a foam core containing a crushed material tightly bound was present inside was obtained.

[0040]

Example 2 This example is an example of producing a flat composite sandwich core molded article by the method of the present invention without using a separation layer.

Vertical 360 mm, Horizontal 260 mm, Thickness 20 mm
Using a stainless steel mold for flat plate molding having a flow path capable of passing through the heat medium, and then arranging glass fiber plain woven cloth (200 g / m ² basis weight) as a reinforcing material on both sides of the cavity wall on the inner surface of the mold. did.

Next, a crushed product obtained by finely crushing a composite molded product (total density 0.4 g / cm ³ ) consisting of a surface layer part molded of epoxy resin and a foamed core part made of epoxy resin inside with a hammer mill. And expandable particles ("Matsumoto Microsphere" F-50D manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.)
Then, 360 g of a mixture of an epoxy resin (Dainippon Ink and Chemicals "Epiclon" / Yukaka Shell Epoxy "Epicoat" 60/40 mixture) at a weight ratio of 60/2/38 was added.

With the mold closed and the vent open to the atmosphere, 110 ° C. oil was poured into the mold, and after about 45 minutes, the mold was cooled and then the mold was opened to release the molded product from the mold. did.

The molded product has a skin without defects such as voids of a thin epoxy resin formed on both surfaces, and is present immediately below the glass fiber reinforcement skin and pressed along the skin to the foam core of the inner layer ( Glass fiber volume content 42%),
Sandwich core molded article having a foam core containing crushed material firmly bonded to the inside (overall density 0.76 g /
It was confirmed that cm ³ ) was obtained.

[0045]

EFFECTS OF THE INVENTION According to the method of the present invention as described above, it is possible to effectively utilize the crushed products of various products recovered after use to manufacture a lightweight and tough FRP composite molded product at low cost. Become.

Further, since the method of the present invention can reuse the recovered product which has been conventionally discarded, it is useful for effective use of resources and prevention of global environment pollution.

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Claims (9)

[Claims] 1. When producing a composite molded article having at least a surface layer formed by a liquid molding resin in a predetermined shape and a core portion made of a foam core, (a) forming a surface layer portion in a molding die. (B) The presence of the expandable resin, the pulverized material of the used recovered product and the liquid molding resin in the portion which becomes the foamed core after molding, (c) after closing the mold, By heating a predetermined region of the mold to a sufficiently high temperature and / or by increasing the temperature of the liquid molding resin due to the reaction heat, the foamable resin located in the core part is heated and foamed to cause volume expansion, whereby the surface layer part is formed. Manufacturing a composite molded article characterized by pressing a forming material against an internal constrained surface of a mold, (d) curing a liquid molding resin, and (e) taking out the obtained composite molded article from the mold. Method. 2. A method for producing a composite molded article having at least a surface layer formed of a liquid molding resin in a predetermined shape, a core portion formed of a foamed core, and a separation layer interposed between the surface layer portion and the core portion. (A) A separating layer is provided in the mold for molding, which does not substantially pass through the expanded resin after expansion and the crushed material of the used recovered product, but allows the liquid molding resin to pass through. (B) Foaming after molding The presence of a foamable resin, a crushed product of a used recovered product, and a liquid molding resin in a core portion, (c) heating a predetermined region of the mold to a sufficiently high temperature after closing the mold, and / or Due to the temperature rise due to the reaction heat of the liquid molding resin, the expandable resin is heated and foamed to cause volume expansion, thereby pressing the separation layer against the internal constrained surface of the mold and dipping the liquid molding resin in the separation layer. , And at least part of it A composite molded article characterized by allowing the separation layer to penetrate to reach the surface layer portion, (d) curing the liquid molding resin, and (e) taking out the obtained composite molded article from a mold. Production method. 3. The method according to claim 1, wherein the crushed material is a crushed material of the fiber-reinforced resin molded product recovered after use. 4. A fiber-reinforced resin composite molded article produced by a method in which a crushed product is obtained by arranging a foamable resin and a liquid molding resin in a portion to be a foamed core after molding in the method according to claim 1 or 2. The production method according to claim 3, wherein the product is a crushed product recovered after use. 5. The production method according to claim 3, wherein the crushed material is a crushed material obtained by collecting the composite molded article manufactured by the method according to claim 1 or 2 after use. 6. The amount of the crushed material used is such that the weight ratio of the crushed material present in the foamed core in the composite molded article after molding is 30 to 7.
The manufacturing method according to any one of claims 1 to 5, wherein the content is within a range of 0 (wt)%. 7. The crushed material according to claim 1, wherein the kind and amount of the crushed material are set within a range such that the density of the foamed core in the molded composite article is 1.6 g / cm ³ or less. Production method. 8. A crushed product having a maximum diameter of not more than a minimum thickness of a composite molded product to be molded is used.
7. The manufacturing method according to any one of 7. 9. The method according to claim 1, wherein the expandable resin is heat-expandable resin particles.