JPH0712614B2 - Method for producing composite molded article and intermediate material used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method for producing a composite molded article and an intermediate material therefor. More specifically, it is used in a method for producing an integrated composite molded article mainly composed of a surface layer part made of a synthetic resin layer containing a fibrous reinforcing material and a core part made of a synthetic resin layer containing bubble-containing particles, and a method therefor. It is related to the intermediate material.

<Prior art> The core part is made of foam and the surface layer part is fiber reinforced resin (FRP)
Since the composite molded article constituted by (1) is excellent in lightness and toughness, it has been put to practical use in various fields and further improved molded articles and manufacturing methods have been proposed.

As a method for producing a composite molded article having the above-mentioned structure, for example, (i) a foam core of a core part is molded in advance, the molded body is wrapped with a woven cloth as a reinforcing material, and then inserted into a mold for molding. Then, the liquid molding resin is injected into the mold to form the surface layer part, and the composite molded product is taken out of the mold, or the member to be the surface layer part is molded in advance and the foaming property is formed in the void in the center part. There is known a method of obtaining a composite molded article by injecting a urethane resin or the like and forming a foamed core in the void. Further, some of these improved methods have been proposed (for example, JP-A-63-162207 and JP-B-5).
0-39107, JP-A-63-15835, JP-A-48-5596
6 gazette, JP-A-48-58062, JP-B-62-24521).

However, all of the above-mentioned conventionally known techniques have the disadvantage that (i) the step of obtaining a composite molded product is diverse and the operation is complicated, and therefore the production efficiency of the molded product is low and the cost is high. , (Ii) the strength and appearance of the obtained composite molded product are unsatisfactory, and (iii) the shape and size of the composite molded product that can be produced are substantially limited.

<Problems to be Solved by the Invention> Therefore, a first object of the present invention is to perform a relatively simple operation of a sandwich composite molded article which is substantially formed from a surface layer portion and a core portion (core portion) containing bubble-containing particles. It is to provide a method that can be obtained in.

It is a second object of the present invention to provide a method having excellent production efficiency, particularly high productivity of composite molded products per molding machine, without using heat-expandable foam or particles.

Another object of the present invention is to provide a method for producing a composite molded article which is lightweight, has a physically high strength, and has a structure having an excellent appearance.

Still another object of the present invention is to provide a method for producing a composite molded article, the shape and size of which can be arbitrarily selected.

Still another object of the present invention is to provide an intermediate material suitable for use in the above manufacturing method.

<Means for Solving the Problems> According to the research conducted by the present inventors, the above-described object can be achieved by the method of the present invention and its intermediate materials described below.

That is, the method of the present invention is for producing a sandwich-shaped composite molded article having a surface layer portion made of a synthetic resin phase containing a fibrous reinforcing material and a core portion made of a synthetic resin phase containing bubble-containing particles. Therefore, a fibrous reinforcing material is placed in a molding die, and a synthetic resin that can be fluidized at the time of molding and a compressed lightweight elastic body particle coexist at a position inside the molding material that should be the core of the molding. A method for producing a composite molded article, characterized in that the synthetic resin is fluidized by heating the inside of the mold and the size of the lightweight elastic body particles is recovered, and then the synthetic resin is solidified.

Then, as typical embodiments of the method of the present invention, a) a fibrous reinforcing material is disposed in the molding die in the vicinity of the inner wall surface of the die, and the fibrous reinforcing material is to be the core of the molded article inside thereof. A mixture of solid synthetic resin that can be melted and fluidized at the time of molding and compressed lightweight elastic body particles is put in the position, and the synthetic resin is flowed in the mold by heating the inside of the mold with the mold substantially closed. And a method of recovering the size of the lightweight elastic particles, and then solidifying the synthetic resin, and b) a fiber in a mold for molding in proximity to an inner wall surface of the mold. A large number of compressed lightweight elastic particles are dispersed in a solid synthetic resin phase that can be melted and fluidized at the time of molding, in which a quality reinforcing material is arranged and which is to be the core of the molded material. Inside the mold with the molded body placed and the mold substantially closed By heating to melt and fluidize the synthetic resin constituting the molded body in the mold and restore the size of the lightweight elastic body particles dispersed in the synthetic resin, and then solidify the synthetic resin. A manufacturing method characterized by the above.

Then, as a preferred embodiment, in each of the above methods, a) between a portion where the synthetic resin that can be fluidized at the time of molding and the compressed lightweight elastic body particles coexist and a portion where the fibrous reinforcing material exists, In a synthetic resin that can be fluidized at the time of molding, as a method of interposing a separation layer through which the fluidized synthetic resin passes but not through the lightweight elastic particles, and b) as a pre-molded body that is placed at a position that should be the core of the molded article. There is a method of using a molded body having a main body portion in which the compressed lightweight elastic body particles are dispersed and a surface layer portion formed of a separation layer that allows the fluidized synthetic resin to pass through but does not allow the lightweight elastic body particles to pass through.

In the above-mentioned method of the present invention, the lightweight elastic particles that have been compressed by the temperature rise are compressed and released in the mold, whereby the volume expansion of the particles is caused, and the force of this volume expansion is maximized. It has the greatest feature in performing internal pressure molding effectively and effectively.

That is, the force due to the volume expansion of the particles is a force and a reinforcing material that presses the fibrous reinforcing material surrounding the particles or the aggregate thereof or the separating layer described later toward the inner wall surface of the mold toward the outside. The particles of the light-weight elastic particles that are compressed and released inside the portion surrounded by directly act on the force that densely forms the core portion. Further, due to the volume expansion of the particles, the flowable synthetic resin existing in the mold moves to the outside through the separation layer, if any, and penetrates into the fibrous reinforcing material and / or in the particle aggregate. Is sufficiently permeated, and the formation of the dense surface layer portion and the core portion is achieved.

Thus, according to the method of the present invention, a composite molded article having the following advantages can be obtained.

(I) A surface layer portion made of a synthetic resin layer containing a fibrous reinforcing material is formed uniformly and tightly over the entire surface of the molded product. Bubble-containing particles are virtually absent in this surface layer portion.

(Ii) Since substantially no lightweight elastic particles are present in the surface layer portion, the surface layer portion thus formed has a dense structure,
The obtained molded product has high physical strength and an excellent appearance.

(Iii) Inside the molded product, a core portion is formed in which the air bubble-containing particles and the synthetic resin are tightly packed together.

(Iv) Since the surface layer portion and the core portion are formed in the closed mold, the surface layer portion and the core portion form a strongly integrated structure by communicating the same synthetic resin.

Next, the molding method of the present invention will be described in more detail.

The molding method of the present invention is performed in one step in a substantially closed mold. The mold used at that time can be substantially sealed at the time of molding as long as it can withstand the molding pressure and temperature, and it is usually the Handlay method, RTM method (Resin Transfer Molding method), or RIM method. (Reaction
Injection molding method) and other molds used in molding methods can be used. The mold material may be metal, wood, ceramics, or resin.

The advantage of the method according to the invention is that, as mentioned above, the compression expansion of the lightweight elastic particles causes a volume expansion of these particles,
This effect is achieved by maximizing and exerting its volume expansion force in a hardening manner, the effect of which is facilitated by the presence of the separating layer.

Therefore, the use of a separation layer is the preferred embodiment for achieving the object of the present invention.

Thus, in the present invention, the separation layer needs to be one that does not substantially pass through the compressed lightweight elastic body particles but can pass through the synthetic resin fluidized by melting or the like during molding.

A further desired performance of the separating layer is that it can withstand its pressure as a result of the volume expansion of the aggregate of said particles. As a result of the volume expansion, the separation layer breaks or holes are formed, and when the lightweight elastic body particles pass through the separation layer, it may be difficult to obtain a composite molded article having good surface properties.

To achieve the performance described above, the size of the openings or pores in the separation layer should be selected based on the size and shape of the lightweight elastic particles in the compressed state.

When using a separation layer through which the compressed lightweight elastic particles can pass, the surface layer portion contains bubble-containing particles, and as a result, the obtained composite molded article does not have sufficient strength, In addition, the appearance will be poor and the commercial value will be low.

Specific examples of the material of the separation layer include woven fabric, knitted fabric, non-woven fabric, web, paper, wire mesh, and porous sheet.
The porous sheet has open pores, and a foam sheet such as polyurethane, polystyrene, or polypropylene, or a porous membrane such as polypropylene or polysulfone formed by a stretching, extraction, or coagulation method is used. The aperture is selected according to the type and size of particles used. Of these, preferred are woven fabrics, knitted fabrics, non-woven fabrics or webs, and these materials may be synthetic resins, natural fibers or inorganic fibers.

It is desirable that the separation layer is a layer that does not allow the compressed lightweight elastic particles to substantially pass therethrough. That is, the structure of the separation layer is determined depending on the structure of the mold used for molding and the structure or shape of the intended composite molded article.
Generally, it is a bag structure or a planar structure. Bag structures are particularly preferred. The bag structure or the planar structure does not have to be a separation layer as a whole, and a part of the bag structure or the planar structure can be replaced by another resin as long as the resin fluidized at the time of molding is passed but the compressed lightweight elastic body particles are not substantially passed. The material may be, for example, a film, a film, a microporous film, or the like.

In the molding method of the present invention, the separation layer may be a structural material integrated with the fibrous reinforcing material forming the surface layer portion. The use of this integrated structural material is one of the preferred embodiments of the method of the present invention. A typical integrated structural material functions as a separating layer as described above,
A fibrous reinforcing material having at least its surface portion.

The fibrous reinforcing material forming the surface layer portion will be described in detail later. When, for example, a woven fabric, a knitted fabric, a non-woven fabric, or a web is used as the reinforcing material, the inner surface portion thereof (that is, the compressed lightweight elastic particles The reinforcing material itself has a function as a separation layer and can also serve as a separation layer as long as it does not substantially pass through these particles in the surface (to which the aggregate contacts). When such a fibrous reinforcing material is used, it is not necessary to separately provide a separate layer. However, the separation layer and the fibrous reinforcing material can be separately used in cooperation with each other, or can be laminated and used integrally.

As the fibrous reinforcing material forming the surface layer of the composite molded article according to the method of the present invention, a fibrous material generally used for reinforcing plastics is used. Examples of the material of the fibrous reinforcing material include glass fiber, carbon fiber, silicon carbide fiber, metal fiber, aramid fiber, polyarylate fiber,
Polyolefin fibers are preferred. Alone or 2
One or more species can be used in combination. In addition to these fibers, polyester fibers, polyamide fibers, viscose fibers, natural fibers and the like can also be used. These fibers may be short fibers, long fibers, or whiskers, but long fibers, particularly continuous fibers, are preferable.

These fibrous reinforcements are commonly used as fibrous structures. That is, the reinforcing material is advantageously a woven fabric (plain weave, woven weave, twill weave, etc.), knit, non-woven fabric, UD yarn (unidirectionally arranged filament) or web.

Short fibers or whiskers (eg silicon carbide whiskers, carbon whiskers, Si ₃ N ₄ whiskers, etc.)
Although it is not suitable to be used as a reinforcing material in the surface layer portion by itself, it can be used as a part of a web or a non-woven fabric.

In the composite molded article aimed at by the present invention, the bubble-containing particles contained in the core are formed by releasing the compression of the lightweight elastic body particles compressed in the molding.

Such lightweight elastic particles have an average particle size of about 50 μm to about 10 mm when uncompressed (at normal pressure), preferably about 50 μm.
Those having an average particle size of 0 μm to about 5 mm are preferred. The lightweight elastic particles have a volume which is recovered by compression from about 10% to about 100% as compared with that before compression, preferably from about 20% to about 6%.
Those that recover 0% are used.

Polyolefin, polyurethane or rubber is shown as a preferred example of the polymer forming the lightweight elastic particles. Such lightweight elastic particles are commercially available, for example, under the trade name of polypropylene beads (for example, PB-MG15P) manufactured by JSP Corp., and these can be used as they are.

Also, as a matter of course, hollow elastic particles or substantially solid elastic particles may be used. Among them, particles having a large number of hollow portions in one particle are preferable. In the case of foam-molded lightweight elastic particles, so-called open-cell foams may be used, but closed-cell foams are preferred. This is because if the resin penetrates into the particles, it takes time to elastically recover when it is softened or melted by heating, and the workability deteriorates. The method for producing such particles is described in, for example, JP-A Nos. 1-234212 and 1-275104. When the particles have a thermal expansion property, it is preferable to leave them for a while and to use them in a state where the thermal expansion property is substantially lost.

In the method of the present invention, it is also possible to use particles in which the surface of compressed lightweight elastic particles is fixed with a thermoplastic resin or the like to fix the compressed state. Such particles are small particles at normal temperature and have good handleability, and the above resin is melted by heating to elastically recover and return to almost the original size, and thus can be industrially advantageously used.

The lightweight elastic particles may be mixed with non-expandable hollow particles that do not substantially expand in volume by heating or compression and opening. The non-expandable hollow particles also need to be substantially impermeable to the separation layer. When the non-expandable hollow particles are mixed with the elastic particles and used, the molding operation becomes easy, and the obtained composite molded article has further excellent toughness and rigidity.

The non-expandable hollow particles may be either inorganic hollow particles or expanded organic expanded particles, but inorganic hollow particles are generally preferred. Examples of non-expandable inorganic hollow particles include glass balloons, silica balloons, and shirasu balloons, which have an average particle size of about 1 μm.
Desirably, the thickness is about 1 mm, preferably about 5 μm to about 0.5 mm. It is desirable that the mixing ratio of the lightweight elastic particles and the non-expandable expanded particles is 10: 1 to 1: 5 by weight, preferably 9: 1 to 1: 3.

In the production of the composite molded article which is the object of the present invention, synthetic resins used for the surface layer portion and the core portion are roughly classified into a thermosetting resin and a thermoplastic resin. Any of these may be a precursor thereof, and in the present invention, these are collectively referred to as a synthetic resin. These resins may be those generally used as molding resins as long as they melt or show fluidity during molding. The thermosetting resin or its precursor is a resin that is cured by a polymerization reaction and / or a crosslinking reaction as a result of molding to give a solid resin,
Generally, a liquid at room temperature is advantageous. What is a precursor?
It is intended to mean monomers and prepolymers. As the thermosetting resin, for example, epoxy resin, polyurethane resin, unsaturated polyester resin or polyvinyl ester resin is preferable. In some cases, a curable polycycloolefin resin may also be used.

The thermosetting resin is used in combination with a curing agent and / or an accelerator in a resin or a precursor thereof (for example, a raw material monomer) as is usually used, and the present invention also uses these in combination. It is possible and advantageous.

On the other hand, as the thermoplastic resin, a resin that is usually used for molding is used as long as it can melt and flow at the molding temperature. It is desirable to use a thermoplastic resin having a fluidity temperature in the range of about 70 ° C to about 230 ° C, preferably in the range of about 80 ° C to about 200 ° C.

Specific examples of the thermoplastic resin include polyolefin (for example, polyethylene and polypropylene), polystyrene, liquid crystal polyarylate resin, phenoxy resin, polyvinyl chloride, and polyoxyalkylene, and among them, polyolefin, polystyrene, and liquid crystal polyarylate resin. Alternatively, a phenoxy resin is preferable. In some cases, a prepolymer that can be a thermoplastic resin can also be used.

In carrying out the molding method of the present invention, first, the fibrous reinforcing agent is arranged along the inner wall surface of the mold, and preferably the separation layer is further provided inside thereof. When the separation layer and the fibrous reinforcing material are integrated, typically when a fibrous reinforcing agent having the function of the separation layer is used, the integrated product is used as the separation layer on the inner wall surface of the mold. It may be arranged on the entire surface so that the surface having the function is the inner side (center part).

How to arrange the separation layer and the fibrous reinforcing material is determined depending on the shape, size, physical properties and intended use of the intended composite molded article.

As described above, the molding method of the present invention effectively utilizes the volume expansion of the aggregate of compressed lightweight elastic particles in the molding process, so that the volume expansion of the aggregate of the particles forms the separation layer in the mold. The separating layer and the fibrous reinforcement should be arranged so that they are pressed together towards the inner surface.

Further, as a matter of course, it is preferable to dispose the separation layer according to the shape of the mold so that the air bubble-containing particles do not enter the surface layer portion of the composite molded article. Even if the separating layer has the property of not substantially passing through the compressed lightweight elastic particles,
In the mold, it is not desirable that these particles flow from a part of the periphery of the separation layer and move to the surface layer due to the imperfect arrangement of the separation layer.

For example, in the case of manufacturing a rod-shaped or columnar molded product, if the separation layer and the fibrous reinforcing material are made into a bag structure (hollow cylindrical shape) and arranged on the inner wall surface of the mold in conformity with the shape of the molded product. Good. Further, when a flat plate molded product is to be manufactured, the separation layer and the fibrous reinforcing agent may be arranged so as to be attached to the entire inner wall surface of the mold. In that case, the separating layer can be a bag structure.

Further, in the case of a flat plate or a planar molded product having front and back surfaces, the separating layer can be provided only on one side of the inner surface of the mold. In this case, on the other side, there may be an example in which a separation layer is not provided, an example in which a material such as a film that does not pass the liquid molding resin is installed instead of the separation layer, an example in which a separation layer is installed, etc. It may be selected accordingly. For example, in the case of a cowling of a motorcycle, by installing a printed film on the front surface side and using a separating layer of a glass fiber fabric on the back surface side, it is possible to simplify the work of coating the front surface side after molding and applying a decal. When a flat plate is formed as a structural material requiring high rigidity, separation layers may be provided on both surfaces, and a fibrous reinforcing material may be arranged between each separation layer and the inner surface of the mold.

As described above, after arranging the separation layer and the fibrous reinforcing material in the mold, the lightweight elastic particles are provided at the position opposite to the mold inner surface of the separation layer, and inside the separation layer when the separation layer is a bag structure. It
Particularly when the separation layer is a bag structure, it is possible to put the lightweight elastic particles in advance outside the mold. It is desirable that the light-weight elastic particles are put in the mold before the mold is closed.

There are several methods for arranging or supplying the synthetic resin in the mold in the composite molded article targeted by the present invention. The methods are roughly classified into the following methods (a) to (c).

(A) Method of mixing or impregnating synthetic resin with separation layer and fibrous reinforcing material (b) Method of mixing synthetic resin with lightweight elastic body particles (c) After closing the mold of synthetic resin, Method of injecting into the mold These methods (a) to (c) can be used alone or in any combination of two or more.

Which of the above (a) to (c) is adopted mainly depends on the type of synthetic resin, particularly whether the synthetic resin is a thermoplastic resin or a thermosetting resin.

When the thermosetting resin or its precursor is liquid at room temperature, the above-mentioned (a), (b), (c) or a combination thereof can be adopted, but (a) is preferable. That is, the liquid thermosetting resin or its precursor is placed in the mold after preliminarily impregnating the fibrous reinforcement in the separation layer and the fiber reinforcement, and then the lightweight elastic particles are placed. A method in which the mold is closed and the temperature is raised to perform molding is advantageous. In this case, the thermosetting resin (or its precursor), according to the compression and opening of the lightweight elastic particles, a part thereof passes through the separation layer from the fibrous reinforcing material and impregnates into the aggregate of the particles, The resin component spreads throughout the mold.

On the other hand, when the thermosetting resin or its precursor is solid at room temperature and can be fluidized at the temperature at the time of molding, the above (a), (b) or a combination thereof is adopted. One of the methods is, specifically, a method of arranging a mixture obtained by previously mixing a fixed powder of a thermosetting resin or a precursor thereof with lightweight elastic particles at a predetermined position in a mold and molding. Is. In this method, the resin component is fluidized by the heating of the mold and the core portion is formed according to the volume expansion of the aggregate of the particles, and at the same time, a part of the core portion flows through the separation membrane into the fiber reinforcing material to form the surface layer portion.

Another improvement of this method is to prepare a solid preform (intermediate material) containing dispersed lightweight elastomer particles pre-compressed outside the mold and having the resin component as a matrix, and This method is used as a mixture of lightweight elastic particles and resin. When this intermediate solid material, which is an integrated solid mixture, is placed at a predetermined position in the mold and the mold is closed and heated, the matrix resin component in the solid mixture is fluidized and compressed into lightweight elastic particles. Is released from compression and expands in volume, and at the same time, a core is formed, and a part of the resin component flows through the separation membrane into the fiber reinforcement to form a surface layer.

This intermediate material is a method of mixing a heat-melted resin that solidifies when cooled and lightweight elastic particles, and pressing the mixture to compress the lightweight elastic particles in the mixture, or the lightweight elastic particles are compressed in a mold. However, it is manufactured by injecting a liquid resin that is solidified by cooling into the mold and cooling it to solidify the resin.

In addition to the lightweight elastic particles, the above-mentioned non-elastic hollow particles can also be used in combination with this intermediate material. Such hollow particles are, for example, smaller than the lightweight elastic particles, and by replacing a part of the resin between the lightweight elastic particles with this, further weight reduction can be achieved. For example,
When the lightweight elastic body is spherical, it is possible to replace a part of the resin located in the space of the closest packing with a ball smaller than the gap when the closest packing is performed. Further, in the final molded product, it is often preferable that the lightweight elastic particles are not in close contact with each other and the resin is interposed between the adjacent particles, and it is expected that the combined use of the hollow bodies facilitates this.

On the other hand, the matrix resin serves as a molding resin for a molded product, and is a curable resin which is solid at room temperature and softened or liquid by heating. As the latter, generally known liquid molding resins such as epoxy resin, unsaturated polyester resin, dicyclopentadiene resin and non-foaming urethane resin are preferably used. In the case of a reactive resin, it may be a precursor or raw material of the polymer.

The thermoplastic resin needs to have fluidity that is softened or melted at a temperature at which lightweight elastic particles do not lose elasticity, and usually has a melting point of 150 ° C or lower. Such resins include polyolefin resins, polystyrene resins,
Phenoxy resin and some liquid crystal resins are preferably used. Low molecular weight thermosetting resins and the like also fall into this category. The range of these resins will expand as the development of lightweight elastic particles progresses, and naturally, also in the development of thermoplastic resins.

In this embodiment, the lightweight hollow elastic body particles as described above are compressed, and a preform, that is, an intermediate material, which is solidified with a matrix resin that is solid at room temperature, is placed at a position where it becomes a porous core of a target molding, and heated. Then, the above resin is melted or softened to recover and expand the shape and size of the lightweight elastic particles, and by utilizing this force, a part of the liquid resin is pushed out of the packed layer of the lightweight elastic particles to expand and recover. It is an attempt to form internal pressure with force. Therefore, a kind of internal pressure molding can be performed by elastic expansion of particles to spread the resin in a predetermined region, and at the same time, a sandwich material or other lightweight molded product can be easily produced by using a solid intermediate material. Therefore, the productivity can be improved.

Release some of the matrix resin that became liquid during molding,
In some cases, it is preferable to release the resin. It is also useful for reducing the amount of resin in the cavity and compensating for variations in the presence of the lightweight elastic particles in the cavity. Therefore, the release of pressure can also be carried out according to its purpose.

The core portion of the obtained molded product is obtained by filling the inside of the pores of the porous portion with a lightweight elastic body. Therefore, the lightweight elastic particles may be present as blocks, but it is more desirable that they are evenly dispersed. Further, when the lightweight elastic particles are used as foam-molded small particles, and when used in combination with other hollow particles, it is preferable to sufficiently mix and disperse these with, for example, foam-molded lightweight elastic particles.

In the method of the present invention, when the synthetic resin component is a thermoplastic resin, the method (a) or (b) described above is preferably used, and the method (b) is particularly preferably used. This method (b) will be described in detail. Basically, the same method as the above method using a thermosetting resin or its precursor that is fixed at room temperature and can flow at the temperature during molding as a synthetic resin component is used. Is the way. That is, one is that a mixture obtained by previously mixing a solid powder of a thermoplastic resin (which can be fluidized at a temperature during molding) with lightweight elastic particles is placed at a predetermined position in a mold. Another improvement method is to prepare a solid preform (intermediate material) containing dispersed lightweight elastic particles previously compressed outside the mold and having a thermoplastic resin component as a matrix. , Is the way to use this.

In any method, the amount and proportion of the fibrous reinforcing material, synthetic resin, lightweight elastic particles, and other separation layers that are allowed to exist in the mold can be variously changed depending on the shape and intended use of the intended composite molded article. it can. However, what is necessary is that the amount of each of the above-mentioned components in the mold is such that no void portion exists after the lightweight elastic particles have undergone volume expansion during molding.

In particular, in the present invention, it is desirable to select and use the fibrous reinforcing material, the synthetic resin component, the lightweight elastic particles, the separation layer and other additives so that the composite molded article has the following compositions (a) to (e). .

(A) About 30 to about 95 (volume)% of the core portion, preferably about 40, in the substantial portion of the composite molded article where the core portion exists.
% To about 90% (b) The specific gravity in the core is about 0.05 to 0.8 g / ml, preferably about 0.1 to 0.6 g / ml (c) The ratio of the synthetic resin component in the core is about 15 ~ 70
(Capacity)%, preferably about 20 to 50% (d) In the surface layer portion, the fibrous reinforcing material and the separating layer are about 30%.
-80% (volume)%, preferably about 30-60% (e) Light-weight elastic particles are substantially absent in the surface layer part. Charge, heat the mold from the outside, or if a thermosetting resin is used, if the curing heat is generated, the temperature inside the mold is raised by the heat generation or both of them, and The pressure is released causing a volume expansion of the aggregate of these particles. When a preform of a synthetic resin matrix containing these particles dispersed therein is used, this matrix component is fluidized to cause volume expansion of the aggregate of these particles.

At this time, it is necessary that at least the synthetic resin component retains fluidity while the volume expansion of the aggregate of these particles occurs. Thus, the separation layer is pressed toward the inner surface of the mold by the volume expansion of the aggregate of the particles,
The flow of the synthetic resin component occurs from the inside (core portion) to the outside (mold inner wall surface) or the outside to the inside through the separation layer.

Thus, a dense surface layer portion is formed, a core portion made of lightweight elastic particles and a synthetic resin is formed, and further, the surface layer portion and the core portion are firmly integrated by communicating with the same synthetic resin through a separation layer. A molded product is obtained.

On the other hand, in molding, after collecting an excessive amount of synthetic resin component in a storage portion of a mold or removing it from a vent, the synthetic resin is cured or cooled to be solidified. Next, the composite molded article formed by opening the mold can be taken out from the mold according to a conventional method, and if necessary, finished into a product.
Further, the obtained composite molded article can be post-cured in an oven.

In the method using the intermediate material, the intermediate material is first molded.
That is, the light weight elastic particles and the solid resin at room temperature that can soften or melt at a temperature at which the particles can maintain elasticity are mixed and heated to melt the latter, and this is pressed to compress the light weight elastic particles. Then, the obtained plate-like material is cooled and solidified as it is to obtain a preformed body as an intermediate material.

Next, a mold for molding is prepared. If necessary, a sheet to be a separation layer is installed along the inner wall surface of this mold. A reinforcing fiber layer is added separately or the sheet of the separating layer is composed of reinforcing fibers. In some cases, a woven fabric or the like may be placed at the vent port of the mold to serve as the resin outlet. The above-mentioned intermediate material is placed between the reinforcing fiber layers or the separating layers, and the mold is closed.

This mold has a gas / liquid vent, and a means for passing the light-weight elastic particles but not the liquid resin is provided between the nozzle and the mold body. Here, although not essential, it is preferable to evacuate the mold. This makes the resin easier to spread. Heat as is (hold this if vacuum is applied). Preferably, the intermediate material matrix resin is softened,
Make sure to melt and overflow from the mold. Then, preferably a part of the pressure is released, the compressed lightweight elastic particles in the intermediate material are allowed to recover and expand, and a part of the liquid resin is overflowed to close the nozzle. If it is a thermoplastic resin, if it is a thermosetting resin, the resin is cured and then cooled and the molded product is taken out.

Thus, according to the present invention, a lightweight and tough composite molded article can be obtained in substantially one step.

EFFECTS OF THE INVENTION According to the present invention as described above, a lightweight and tough composite molded article can be manufactured with high productivity and at low cost. The resulting composite molded article is, for example, a canoe paddle, mast, rudder,
Windsurfing rudder (skeg), human powered hydrofoil,
Skis (boards, poles), hockey sticks, baseball bats, wheels without spokes, bicycle frames, sports equipment fields such as skateboards, spoilers for automobiles (passenger cars, buses, trucks), drive shafts, interior and exterior products, Vehicle fields such as vehicle doors and structural members (CF, GF), industrial fields such as heat exchanger end plates, air conditioners, compressor blades, stirring blades, electrical insulation support beams, fittings, etc., wheelchairs (hand rims, side panels) , X
Line projection table, medical instruments such as artificial hands and legs, propellers, seats, furniture, control surfaces, 2
It can be effectively used for a wide range of applications such as the following structural materials and reflectors for satellite broadcasting antennas.

Then, according to the method of the present invention, a lightweight structural material such as a honeycomb material having a good surface can be obtained without using a thermally expansive material such as a foaming resin.

The initial object of the present invention was to produce a composite molded article using a lightweight elastic body, which does not require heat-expandable particles or foam and has a porous inner layer. However, when the method of the present invention was actually carried out, it was found that the weight of the product was reduced rather than the case of thermal expansion molding in which inorganic hollow particles such as glass balloons were used in combination. . This is considered to be because the specific gravity of elastic particles such as polypropylene foam is generally made lower than that of the current inorganic hollow particles. It was also confirmed that even with a molded product in which some resilience remains in the elastic body, the elastic body contained therein does not cause any particular problem as long as the curing of the resin that hits the core cell is completed.

[Examples] Next, examples of the present invention and comparative examples will be described, but the present invention is not limited thereto. Unless otherwise specified, "part" in each example is part by weight.

Example 1 100 parts of an epoxy resin "Epicoat 807" made of shell and 31 parts of a curing agent "Epimate YLH006" were mixed. This is referred to as liquid resin A.

On the other hand, commercially available polypropylene beads as lightweight elastic particles
I got PB-MG15P. This was left for a while so that it would not thermally expand. Its bulk specific gravity was about 0.05 g / cm ² . 36 parts of these beads were prepared.

We prepared two male dies with a maximum width of 120 mm, a maximum length of 350 mm, and a maximum thickness of 14 mm to make a rudder model. Nozzles were provided above and below the mold. Six leaves of glass cloth were also prepared according to this mold. Polyester non-woven fabric "UNICEL BT-0404"
Was formed into a bag in conformity with the mold, and the above polypropylene beads were placed therein and sealed.

The bag containing the polypropylene beads was centered, covered with a glass cloth, housed in a mold, and the mold was closed. Nitrogen pressure was applied to this mold to set the internal pressure to 1.5 kg / cm ² . As it was, epoxy resin was pushed into this mold. The resin was press-fitted from below and overflowed from the nozzle above. The nozzle was slightly opened, and the nozzle was closed while the resin came out.

The mold containing the resin was placed in a hot bath at 70 ° C. to cure the resin. After holding for 1 hour, the molded product was taken out from the warm bath and cooled. A good model with a specific gravity of 0.8 was obtained.

Example 2 100 parts of unsaturated polyester resin, curing agent and accelerator, "Yupica X-314", "Lupazole 224" manufactured by Nippon Yupica
(Peroxide) 1 part, PRM (cobalt catalyst) 0.5
Parts mixed. This is referred to as liquid resin B.

3 parts of the same polypropylene foam molding particles as in Example 1 and 1 part of Asahi Glass inorganic hollow balloon M28 were mixed. This is mixture C.

A slightly smaller bag was made of the same polyester / polypropylene non-woven fabric "Unicel" as in Example 1 according to the inner size of the mold. This bag was filled with mixture C.

A mold was made by sandwiching a "Teflon" frame between two aluminum plates. Nozzles were provided at the top and bottom edges. 6 pieces of general glass cloth and 8 pieces of strip-shaped glass cloth whose length is adjusted to the shape of the mold and the width is set to cover the nozzle,
A large glass cloth was used and placed in the mold in the order of glass cloth / foaming mixture C bag / glass cloth. A small glass cloth was overlapped to fill the position covering the nozzle, that is, the upper and lower ends.

Liquid resin B was pressed into this mold in exactly the same manner as in Example 1. This was placed in a 70 ° C warm bath.

After 1 hour, the molded product was taken out of the hot bath, cooled, and taken out of the mold. A lightweight and good sandwich material having a glass fiber reinforced polyester on the surface and polypropylene foam and polyester on the inner layer was obtained. This sandwich material is flexural strength 6.2 kg / mm ^2, was elastic modulus 880 kg / mm ^2.

Example 3 Polypropylene beads PB-MG15P of JSP Co., Ltd. were obtained. This was left to stand so that it would not thermally expand. The bulk specific gravity was about 0.05 g / cm ² . These are particles that have the property of shrinking by compression and restoring by pressure release.
This is PPB.

Epoxy resin and curing agent made of shell, "Epicoat 100
1 part (which itself is thermoplastic) 70 parts, "Epicoat 3
48 parts (30 parts), phthalic anhydride (30 parts), and "Epomate YLH185" (1 part) were mixed at 80 ° C. This is designated as hot-melt resin A.

50 parts of PPB and 100 parts of resin A were mixed at 80 ° C., placed in a mold preheated to 80 ° C., compressed under a pressure of 7.5 kg / cm ² , and immediately cooled and solidified. The mold was opened to obtain a thin plate having a thickness of about 5 mm. This thin plate is referred to as an intermediate material B.

A mold having a frame of "Teflon" (registered trademark) sandwiched between two aluminum plates was prepared, and nozzles were provided at the upper and lower ends. A strip-shaped glass cloth that uses Nitto Boseki's glass fiber cloth WF-181-100BV and has two mold-filled glass cloths and a length matched to the mold, and a width that covers the nozzle.
I made 10 pieces. Using a large glass cloth, the glass cloth / intermediate material B / glass cloth was placed in the mold in this order. The position where the nozzle is covered, that is, the upper and lower ends are not the intermediate material B, but a small glass cloth is overlaid so that polypropylene beads do not enter this position. The inside of the mold was evacuated using both nozzles. Then, the mold was placed in a silicon oil bath at 145 ° C. and heated. A small amount of resin and gas were overflowed to the position of the nozzle, and the nozzle was sequentially closed. It was almost the same time. After heating for 1 hour, the mold was taken out from the warm bath, cooled, and the molded product was taken out from the mold. Thus, a good sandwich composite material was obtained in which glass fiber reinforced epoxy resin was used for the front surface, and foamed polypropylene was dispersed in the epoxy resin for the inner layer. The obtained molded product is evenly spread over the polypropylene molded product except for the part containing the small glass cloth.
The density was 0.52 g / cm ² . Furthermore, the bending strength of the molded product is 3.3 kg / mm ^2, an elastic modulus of 397 kg / mm ^2.

Example 4 PPB, resin A and intermediate material B were prepared in the same manner as in Example 3.

We prepared two male dies with a maximum width of 120 mm, a maximum length of 350 mm, and a maximum thickness of 14 mm to make a rudder model. Nozzles were provided above and below the mold. 4 leaves of glass cloth and 2 leaves of carbon cloth were prepared according to this mold. The glass cloth is the same as in Example 3, which is a glass fiber cloth WF-181-100 manufactured by Nittobo.
BV and carbon cloth is Toray's carbon fiber fabric C06304
Is. On the other hand, a polyester non-woven fabric "UNICEL BT-0404" manufactured by Unicell Co., Ltd. was put into a bag in accordance with the mold.

The intermediate material B was cut into a slightly smaller size according to the inner shape of the mold. Put this intermediate material in a "Unicel" bag,
It was sandwiched between glass cloths and placed in a mold.

The mold was evacuated and placed in a warm bath of silicone oil at 160 ° C. After confirming that the resin and gas came out from each nozzle, the nozzle was closed. After holding for 1 hour, the molded product was taken out from the warm bath and cooled. As a result, specific gravity
A good model of 0.8 was obtained.

Example 5 A mold having a cross section of 20 mm × 20 mm and a length of 500 mm was prepared. Nozzles were provided at both ends.

PPB, resin A, and intermediate material B were prepared in the same manner as in Example 3. However, the intermediate material B was cut into a rod shape.

The polyester nonwoven fabric “UNICEL BT-040” used in Example 4
A tube with a circumference of 80 mm was made with "4" and filled with the above-mentioned rod-shaped intermediate material B.

A unicell tube containing the intermediate material B was covered with two layers of carbon fiber blades and one layer of glass fiber blades. The blade used was a carbon fiber blade, "Torayca T-3964",
"Torayca T-3484", glass fiber blade is "Atkins and Piers"# 9273. T-3484, # 927
3, T-3964 in this order.

This was placed in the mold and the mold was closed. The mold was made horizontal, and the inside of the mold was once decompressed with a vacuum pump to make it almost vacuum. It was put in a warm bath at 150 ° C. in the same manner as in Examples 3 and 4 and cured while removing the resin. After 1 hour, the molded product was taken out of the hot bath, cooled, and taken out of the mold. A light-weight timber having a carbon fiber / glass fiber reinforced epoxy resin on the surface and an epoxy resin and polypropylene foam on the inner layer was obtained. The specific gravity including the skin of this timber was 0.56 g / cm ³ .

Example 6 Phenoxy resin “Phenothote YB-5” manufactured by Tohto Kasei Co., Ltd.
I got "0". The pour point of this resin is 150 ° C. or lower, and when melted, it has a relatively low viscosity.

Meanwhile, a synthetic rubber foam molded product (particle) prototype was obtained.
It was confirmed that the expanded beads had a specific gravity of about 0.8 and could withstand use at 160 ° C for several hours. 3 parts of this foamed particle and 1 part of inorganic hollow balloon M28 manufactured by Asahi Glass were mixed. Further, this was mixed with 5 parts of a phenoxy resin, pressurized at 150 ° C. to 10 kg / cm ² , and cooled as it was. This is an intermediate material C.

A mold was made by sandwiching a "Teflon (registered trademark)" frame between two aluminum plates. Nozzles were provided at the top and bottom edges. Six strips of glass cloth filled with a die and eight strips of glass cloth having a length matched with the die to cover the nozzle are made, and the same polyester / polypropylene non-woven fabric "Unicell" as in Example 1 is used to die. I made a slightly smaller bag according to the inside dimensions. The intermediate material C was cut into the bag according to the size of the portion of the mold except the cloth and stored.

Using a large glass cloth, the glass cloth, the bag of the intermediate material C, and the glass cloth were placed in this order in this order. A small glass cloth was overlapped to fill the position covering the nozzle, that is, the upper and lower ends. Then, this was placed in a 160 ° C. hot bath.

After 1 hour, the molded product was taken out of the hot bath, cooled, and taken out of the mold. The surface is glass fiber reinforced phenoxy resin,
A lightweight and good sandwich material in which the inner layer was a phenoxy resin containing a synthetic rubber foam was obtained.

Example 7 The epoxy resin "Epicoat 1001" used in Example 3 is a resin which itself exhibits thermoplasticity at a pour point of 80 ° C or lower.
Similar trials were made using only this resin.

Resin as "Epicoat 1001" and 100 to 100 together with PPB
After mixing at a ratio of 80 ° C. and melting at 80 ° C., a sheet-shaped intermediate material D was made by pressurizing to 7.5 kg / cm ² , sandwiched between glass cloths, placed in a mold, put in a warm bath at 145 ° C., and heated. The obtained sample was the same as in Example 1 and had a specific gravity of 0.45 g / cm ³ . When 100 parts of "Epicoat 1001", 100 parts of PPB and 50 parts of glass beads M28 were mixed, the specific gravity was 0.42, and the weight was further reduced.

Example 8 This example is an example of making a square rod.

A mold with a cross section of 20 mm × 20 mm and a length of 500 mm was made, and nozzles were provided at both ends. Shell-made epoxy resin "Epicote 807"
Was mixed with 100 parts, and 31 parts of a curing material "Epomate YLH006" was mixed. This is designated as resin A. The amount of resin is 393 parts. Commercially available polypropylene beads PB-MG15P were obtained. This was left for a while so that it would not thermally expand. Its bulk specific gravity was about 0.05 g / cm ³ . It is elastic and recovers when compressed. 10 parts of these beads were prepared.

A tube with a circumference of 80 mm was made with "Unicel BT0404" and filled with 1/2 of the above polypropylene beads.

A "Unicel" cylinder containing polypropylene beads was covered with two layers of carbon fiber blades and one layer of glass fiber blades. The blades used are "Torayca T-3964" and "Torayca T-3484", and the glass fiber blade is "Atkins and Pierce"# 9273. These are T-3484, #
9273 and T-3964 are stacked in this order.

This was placed in the above mold, the remainder of the polypropylene beads was pushed in, and the unicell cylinder and mold were closed.

The mold was made horizontal, the pressure was once reduced by a vacuum pump to a vacuum, and the pressure was increased by nitrogen. Liquid resin A was injected as it was, and it was confirmed that the resin had overflowed, and the injection was stopped.

The mixture was placed in a warm bath at 70 ° C. and cured while removing the resin. After 1 hour, the molded product was taken out of the hot bath, cooled, and taken out of the mold. Thus, a light-weight square bar having a carbon / glass fiber reinforced epoxy resin on the surface and an epoxy resin / polypropylene foam on the inner layer was obtained. The specific gravity including the epidermis is 0.
It was 56 g / cm ² .

Front page continuation (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area B29K 33:00 63:00 67:00 75:00 105: 04 105: 06 B29L 9:00

Claims (11)

[Claims] Claims: 1. In producing a sandwich-shaped composite molded article having a surface layer portion made of a synthetic resin phase containing a fibrous reinforcing material and a core portion made of a synthetic resin phase containing bubble-containing particles, molding is carried out. The fibrous reinforcing material is placed in the mold for use, and the synthetic resin that can be fluidized at the time of molding and the lightweight elastic particles that have been compressed coexist at a position to be the core of the molded product inside the mold, A method for producing a composite molded article, characterized in that the synthetic resin is fluidized by heating and the size of the lightweight elastic particles is recovered, and then the synthetic resin is solidified. 2. A synthesis of a solid capable of being melted and fluidized at the time of molding, by disposing a fibrous reinforcing material in a molding die in the vicinity of an inner wall surface of the die and at a position to be a core portion of the molded article inside thereof. Put a mixture of resin and compressed lightweight elastic particles, and fluidize the synthetic resin in the mold by substantially heating the inside of the mold with the mold closed to restore the size of the lightweight elastic particles. The method according to claim 1, wherein the synthetic resin is then solidified. 3. A fibrous reinforcing material is disposed in a molding die in the vicinity of an inner wall surface of the die, and a solid material which can be melted and fluidized at the time of molding is disposed at a position inside the fibrous reinforcing material to be a core portion of the molding. A preform in which a large number of compressed lightweight elastic particles are dispersed in a synthetic resin phase is placed, and the preform is heated in the mold by heating the inside of the mold with the substantial mold closed. The method according to claim 1, wherein the synthetic resin is melted and fluidized, and the size of the lightweight elastic particles dispersed in the synthetic resin is restored, and then the synthetic resin is solidified. 4. The fluidized synthetic resin is passed between the portion where the synthetic resin that can be fluidized at the time of molding and the compressed lightweight elastic particles coexist and the portion where the fibrous reinforcing material is present, but the lightweight elastic particles are The method according to claim 1, 2 or 3, wherein a separation layer that does not pass through is interposed. 5. As a preform to be placed at a position to be a core of a molded article, a main body having compressed lightweight elastic particles dispersed in a synthetic resin that can be fluidized at the time of molding and a fluidized synthetic resin are passed. 5. The method according to claim 3 or 4, wherein a molded body having a surface layer portion composed of a separation layer that does not allow the lightweight elastic particles to pass therethrough is used. 6. The method according to claim 1, wherein the synthetic resin is a thermoplastic resin that melts at a molding temperature. 7. The production method according to claim 1, wherein the synthetic resin is a thermosetting resin that exhibits fluidity at least at a molding temperature. 8. The method according to claim 7, wherein the thermosetting resin is a resin which is substantially solid at room temperature. 9. The method according to claim 1, wherein the mixture or preform containing the lightweight elastic particles further contains non-expandable inorganic hollow particles. 10. The method according to claim 1, wherein the separation layer is a bag structure, contains compressed lightweight elastic particles in the bag structure, and further contains a synthetic resin. 11. A preformed body in which a solid synthetic resin fluidized by heating is used as a matrix, and a large number of compressed lightweight elastic particles are bonded and integrated with the matrix resin, and The size of the compressed lightweight elastic particles can be recovered by heating the matrix resin to fluidize the matrix resin.
Intermediate material used in the method described in 10.