JP2021041634A - Method for molding laminated composite sheet comprising fiber reinforced resin sheet and resin foamed sheet - Google Patents

Abstract

To provide a manufacturing method capable of obtaining a laminated composite sheet molding having a uniform thickness and flatness.SOLUTION: In a method for manufacturing a laminated composite sheet, two molded fiber reinforced resin sheets 1 are brought into close contact with each of inner surfaces of a pair of molds 10 and 11 comprising a metal with a high thermal conductivity and having the same, uniform thickness. A gap between the fiber reinforced resin sheets is uniformly held, and a foamable resin mixture 2 uniformly mixed with thermoexpansible foaming particles is filled into the gap. Next, heated metal bodies 20 and 21 are brought into contact with respective outer surfaces of the molds, and they are heated simultaneously from both outer surfaces to raise the temperature to a temperature at which the fiber reinforced resin sheets are not thermally deformed. The thermoexpansible foaming particles are expanded to mold the foamable resin mixture into a foamed resin sheet 3, and at the same time, laminate and integrate with the fiber reinforced resin sheets. Then, instead of the heated metal bodies, cooled metal bodies 30 and 31 are brought into contact to simultaneously chill the mold and the laminated and integrated sheets from both outer surfaces.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for molding a laminated composite sheet composed of a fiber-reinforced resin sheet and a resin foamed sheet, and more particularly to a method for molding a laminated composite sheet in which a resin foamed sheet is sandwiched between fiber-reinforced resin sheets.

Since fiber reinforced plastic is lightweight and has excellent mechanical strength, it is used in application fields where high mechanical strength and light weight are required, such as the frame and interior materials of vehicles, ships, aircraft, etc., and the housing of electronic devices. It is becoming more and more popular. Further, by combining the fiber-reinforced resin molded body with the porous resin foam molded body, the weight can be further reduced, and further, the laminated composite molded body obtained by this combination becomes a material having excellent shock absorption. Therefore, many proposals have been made so far for a laminated composite molded product composed of a fiber-reinforced resin molded product and a resin foam molded product.

However, in a laminated composite molded product having a sandwich structure in which a fiber-reinforced resin molded product is laminated on a resin foam molded product, a sheet molded product having a uniform wall thickness and flatness has not been obtained. This is because it is difficult to cut out a thin sheet from the block of the resin foam molded product, and it is difficult to control the wall thickness and density of the entire sheet in order to mold the resin foam molded product into a thin sheet. That is the factor. On the other hand, it has also been proposed to form a laminated composite molded product by simultaneously heat-molding a fiber-reinforced resin molded product and a resin foam molded product.

For example, in Patent Document 1, a thermoplastic resin layer containing unfoamed foam particles is arranged in a mold as a core layer, and a carbon fiber reinforced thermoplastic resin composite material is arranged as a skin layer in the mold to foam the mold. The carbon fiber reinforced thermoplastic resin sandwich molded body is formed by heating the particles above the foaming start temperature to expand the foamed particles in the thermoplastic resin and then cooling the mold below the melting temperature of the thermoplastic resin. It is stated that it will be obtained. However, in the manufacturing method according to the present document, the core layer and the skin layer are heated at the same time, the thermoplastic resin is melted or softened to be molded, and then the molded product is cooled to manufacture the molded product. The structure of the skin layer using carbon fiber as a reinforcing material and the core layer foaming without containing a reinforcing material are different, and the behavior of expansion due to heating and contraction due to cooling during molding is also different. In the case, the internal stress and strain generated during molding are large, and uniform wall thickness and flatness cannot be obtained when molding into a sheet, and particularly when the wall thickness is thin, uniform wall thickness and flatness are obtained. It is difficult to obtain a sheet molded product.

Patent Document 2 describes a fiber reinforced material in which the surface of a refoamable foam core material composed of a synthetic resin such as an acrylic resin and a thermoplastic polyester resin is impregnated with a thermoplastic resin or an uncured thermoplastic resin. It is described that a fiber-reinforced composite is produced by heating a laminated laminate in a mold to foam a foamed core material and pressing the fiber-reinforced material against the mold with foaming pressure. However, as in the manufacturing method of Patent Document 1, since the foam molding of the foam core material and the molding of the fiber reinforced material are performed at the same time in the manufacturing method of this document, a thin sheet molded body is manufactured as a fiber reinforced composite. In this case, it is difficult to obtain a sheet molded product having a uniform wall thickness and flatness as described above.

In Patent Document 3, a fiber-reinforced resin material is placed in a molding die, thermoplastic foamed particles are further filled in the molding die, and then the foamed particles are foamed to melt the fiber-reinforced resin material and the foamed particles. It is described that a fiber-reinforced composite foam is produced by laminating and integrating with a resin foam which is a body. Then, a specific material is used for the bulk density, the maximum coefficient of thermal expansion, and the expansion rate of the thermoplastic foam particles used. However, also in this manufacturing method, since the resin foam as the core layer and the fiber reinforced resin material as the surface layer are simultaneously heat-molded as in Patent Documents 1 and 2, they are also uniform as described above. It is difficult to obtain a thin sheet molded product having a large wall thickness and flatness.

Japanese Unexamined Patent Publication No. 2012-196899 Japanese Unexamined Patent Publication No. 2014-208420 JP-A-2017-43011

An object of the present invention is a laminated composite sheet having a fiber-reinforced resin sheet as a skin layer and a resin foam sheet as a core layer, and a sheet molded product having a uniform wall thickness and flatness even when the wall thickness is thin. It is the provision of a manufacturing method that can be obtained.

In the method for producing a laminated composite sheet of the present invention, two molded fiber-reinforced resin sheets are adhered to the inner surfaces of a pair of dies having a uniform and the same wall thickness, which are made of a metal having a high thermal conductivity. The pair of dies are set in a state where the gaps between the fiber-reinforced resin sheets are uniformly maintained and the gaps are filled with a foamable resin mixture in which thermally expandable foam particles are uniformly mixed. Next, the heated metal body is brought into contact with each outer surface of the mold and heated simultaneously from both outer surfaces to thermally expand the filled foamable resin mixture at a temperature at which the fiber-reinforced resin sheet is not thermally deformed. The temperature is raised above the thermal expansion start temperature of the sex foam particles and below the maximum expansion temperature to expand the thermally expandable foam particles, and the foamable resin mixture is molded into a resin foam sheet and laminated and integrated with the fiber reinforced resin sheet. Then, instead of the heated metal body, the cooling metal body is brought into contact with the mold and the laminated and integrated sheet is simultaneously cooled from both outer surfaces. A manufacturing method in which the fiber-reinforced resin sheet is used as the skin layer and the resin foam sheet is used as the core layer. Is.

The production method of the present invention is characterized in that a preformed fiber resin reinforced sheet is used before laminating and integrating the fiber reinforced resin sheet and the resin foam sheet, and the fiber reinforced thermosetting resin base material or fiber. A fiber reinforced resin sheet formed by heating and pressurizing a reinforced thermoplastic resin base material is placed in a mold made of a highly thermally conductive metal and rapidly heated by a heated metal body to form a fiber resin reinforced sheet. The foamable resin mixture filled in the gaps between the fiber reinforced resin sheets is heated to form a resin foam sheet at a temperature that does not cause thermal deformation, and is laminated and integrated with the fiber reinforced resin sheet. Is.

The pair of molds are made of a metal having high thermal conductivity, have a uniform and the same wall thickness, and by bringing a heated metal body into contact with the outer surface of each mold, each mold can be made in a short time. It is heated equally and uniformly, and the two fiber-reinforced resin sheets and the foamable resin composition in the mold are also heated uniformly in a short time. As for cooling, the cooling metal is pressed against the outer surface of each mold to cool the mold at the same time. Therefore, the heat history applied to the fiber-reinforced resin sheet in the mold and the foamable resin composition is the same for both the molds. Therefore, the occurrence of internal distortion is suppressed.

The metal having a high thermal conductivity constituting the mold is a metal having a thermal conductivity of 100 W / m · K (20 ° C.) or more, and a metal such as aluminum, copper, zinc, or magnesium should be used. However, it is preferable to use an alloy containing aluminum as a main component, such as aluminum or duralmin.

The foamable resin mixture is preferably a liquid, paste-like, or powder-like resin mixture for filling the gap between the two molded fiber-reinforced resin sheets, and thermally expands into a thermosetting resin or a thermoplastic resin. It is a mixture in which the plastic foam particles are uniformly mixed. Thermosetting resins are usually used as resin compositions to which a curing agent or the like is added, and are often used as liquid or paste-like resin compositions, and are unsaturated polyester resins, epoxy resins, phenol resins, vinyl ester resins. The heat-expandable foamed particles can be uniformly mixed with the resin such as, to obtain a foamable resin mixture. When a thermoplastic resin is used, a foamable resin mixture can be obtained by blending heat-expandable foamed particles with a powdery resin made of particles obtained by pulverization or emulsion suspension polymerization and mixing them with a blender. .. Further, a vinyl chloride paste in which a plasticizer such as DOP is mixed with a fine powder resin of polyvinyl chloride (PVC) can also be used. When this PVC paste is heated, the fine powder resin absorbs the plasticizer and solidifies. Further, a filler can be added to the foamable resin mixture, and various inorganic powders, milled fibers and the like can be added.

Further, in the preparation of the foamable resin mixture, when the heat-expandable foamed particles are uniformly mixed with the liquid or paste-like thermosetting resin or the thermoplastic resin, the bubbles generated in the foamable resin mixture are defoamed. It can be used for manufacturing a laminated composite sheet without any problem. In this case, the bubbles generated in the mixing operation are filled in the gaps between the two fiber-reinforced resin sheets and expanded by being heated in the mold, and in the resin foam sheet, the heat-expandable foam particles are used. It can be added to the bubbles formed.

The heat-expandable foamed particles are particles in which a foaming expansion agent is enclosed inside a shell forming the surface of the particles. The foaming expansion agent is vaporized by heating, and the shell is softened by the vapor pressure thereof. Is expanded, the particles expand, and the volume becomes several to 100 times. The shell is formed from a film-forming substance such as a synthetic resin, and a volatile organic solvent is used as the foaming agent. Then, the temperature at which the heat-expandable foam particles are heated, the shell is softened, the shell is expanded by the vapor pressure of the vaporized foam-expanding agent, and the heat-expandable foam particles start to expand is the thermal expansion start temperature, and further. The maximum expansion temperature is the temperature at which the vaporized foam expansion agent permeates and diffuses to the outside through the shell that has been softened and the wall thickness has become thin due to the temperature rise, and the thermally expandable foam particles begin to shrink.

The above-mentioned heat-expandable foamed particles are preferably particles in which a volatile solvent is sealed inside a shell made of a thermoplastic resin, and have an average particle size of 5 to 300 μm, preferably 5 to 150 μm. Is preferable. As the thermoplastic resin constituting the shell, a polyvinylidene chloride resin, an acrylic resin, an AN copolymer resin or the like can be used, and as the volatile solvent, a low boiling point hydrocarbon or the like can be used.

The fiber-reinforced resin sheet is a sheet formed by heating and pressurizing a fiber-reinforced thermosetting resin base material or a fiber-reinforced thermoplastic resin base material. These resin base materials are fiber bundles or fibers in which thermosetting resin or thermoplastic resin is used as a matrix resin, and reinforcing fibers such as glass fiber, carbon fiber, and aramid fiber are arranged in one direction to form roving or yarn. The resin base material can be a cloth impregnated with a woven or knitted cloth or a chopped fiber obtained by cutting a reinforcing fiber and mixed with a matrix resin.

As the matrix resin used for the above resin base material, various thermosetting resins or thermoplastic resins can be used. As described above, the thermosetting resin is usually used as a liquid or paste-like resin composition to which a curing agent or the like is added, and is impregnated with reinforcing fibers to form a fiber-reinforced thermosetting resin base material. Can be done. In this case, the thermosetting resin composition can be semi-cured and used as a prepreg sheet, and various prepreg sheets are also commercially available. Fiber-reinforced thermoplastic resin base materials using a thermoplastic resin as the matrix resin are also commercially available as stampable sheets, and these resin base materials can be heated and pressed to form a fiber-reinforced resin sheet. Further, a prepreg sheet using a resin composition obtained by adding an acid anhydride as a cross-linking agent to a phenoxy resin which is a thermoplastic resin as a matrix resin can also be used. As the fiber-reinforced resin sheet using these base materials, a sheet formed into a sheet having a wall thickness of 0.05 to 1.0 mm is preferably used.

Further, as the temperature at which the fiber-reinforced resin sheet is not thermally deformed, the temperature under a high load (1.80 Mpa) of the deflection temperature under load can be used as a reference, and is a temperature within a range not reaching this temperature.

Since the manufacturing method of the present invention has the above-mentioned structure, the laminated composite sheet molded by this method can obtain a uniform wall thickness even when the wall thickness is several mm or less, and the inside can be obtained. A sheet molded product having uniform flatness without the occurrence of warpage due to strain can be obtained.

The cross-sectional schematic explanatory drawing which shows the manufacturing method of the fiber reinforced resin sheet. FIG. 6 is a schematic cross-sectional explanatory view of a mold set when the formed sheet shape is a curved curved surface.

Hereinafter, the embodiments for carrying out the present invention will be described in more detail.

FIG. 1 shows the manufacturing method of the present invention as a schematic cross-sectional explanatory view. In (A), the foamable resin mixture 2 is filled in the gap between the two molded fiber-reinforced resin sheets 1 and formed on the inner surfaces of the pair of dies 10 and 11 set on the parting surface 13. The process arranged in the cavity 12 is schematically shown. In (B), the foamable resin mixture 2 is resin-foamed by bringing the heated metal bodies 20 and 21 into contact with the outer surfaces 10a and 11a of the pair of molds 10 and 11 set and heating them simultaneously from both outer surfaces. The process of molding into the sheet 3 and laminating and integrating with the fiber reinforced resin sheet 1 is schematically shown. In (C), instead of the heated metal bodies 20 and 21, the cooling metal bodies 30 and 31 are brought into contact with each other and cooled simultaneously from both outer surfaces, and the fiber reinforced resin sheet 1 and the resin foam sheet 3 are laminated and integrated. The process of completing the molding of the sheet 100 is schematically shown.

The two molded fiber-reinforced resin sheets 1 arranged inside the pair of left and right dies 10 and 11 shown in the step (A) and the foamable resin mixture 2 filled in the gaps between them are formed by the step (A). In B), it is heated evenly in a short time by the heated metal bodies 20 and 21 via the pair of left and right dies 10 and 11, and in the step (C), it passes through the pair of left and right dies 10 and 11. Then, by being uniformly cooled by the cooling metal bodies 30 and 31 in a short time, the molded laminated composite sheet 100 has a uniform flatness without warpage due to the occurrence of internal strain, and the wall thickness is uniform. It can be a sheet molded product.

In the step (A), the foamable resin mixture 2 is filled in the gap between the two molded fiber-reinforced resin sheets 1 and formed on the inner surfaces of the pair of dies 10 and 11 set on the parting surface 13. It is placed in the cavity 12. As a specific procedure, the fiber-reinforced resin sheet 1 is closely arranged on the inner surfaces of the molds 10 and 11, and the foamable resin mixture 2 uniformly mixed in advance is arranged on the inner surface of these resin sheets by coating or the like, and then arranged. , Molds 10 and 11 are brought into close contact with each other on the parting surface 13 and set. The cavity 12 is adjusted so that the gap between the fiber-reinforced resin sheets 1 filled with the foamable resin mixture 2 has a width t when the molds 10 and 11 are set. In this case, if necessary, a spacer having a wall thickness t may be arranged in the inner peripheral portion of the fiber reinforced resin sheet 1 arranged in the cavity 12 to maintain the gap width t of the fiber reinforced resin sheet 1. Further, when setting the molds 10 and 11, in order to match the gap width t, excess foamable resin is discharged to the outside of the mold, or if insufficient, it is added to the foamable resin mixture 2. Adjust the filling amount. This gap width t corresponds to the wall thickness of the resin foam sheet 3 after molding. The gap width t is preferably adjusted in the range of 0.3 to 10 mm.

In order to arrange the foamable resin mixture 2 in the gap between the two fiber-reinforced resin sheets 1 in this way, the foamable resin mixture 2 must be a liquid, paste, or powder resin mixture. preferable. As such a mixture, as described above, a mixture in which thermosetting resin or thermoplastic resin is uniformly mixed with heat-expandable foamed particles is used. The thermosetting resin is used as a resin composition to which a curing agent or the like is added, and is often used as a liquid or paste-like resin composition, and is preferably used. When a thermoplastic resin is used, a foamable resin mixture can be obtained by blending heat-expandable foamed particles with a powdery resin made of particles obtained by pulverization or emulsion suspension polymerization and mixing them with a blender. .. Further, it can be made into a paste like the above-mentioned PVC paste. These foamable resin mixtures can be heated to form a resin foam sheet.

Then, in order to prevent the occurrence of internal strain in the molded laminated composite sheet 100, in the step (B), the pair of molds 10 and 11 dissipate heat conducted from the heated metal bodies 20 and 21 in contact with each other for a short time. It is necessary to conduct the heat to the two fiber-reinforced resin sheets 1 arranged inside and the foamable resin mixture 2 filled in the gaps equally and uniformly on the left and right sides, and further, in the step (C), the step (B). ), It is necessary to conduct heat equally and uniformly to the cooling metal bodies 30 and 31 in a short time. Therefore, the pair of molds 10 and 11 are made of a metal having high thermal conductivity, and each of them needs to have a uniform and the same wall thickness. In the molds 10 and 11 shown in FIG. 1, the distances between the outer surfaces 10a and 11a and the inner surfaces 10b and 11b are unified by the wall thickness d, and a thin plate is preferable in order to simultaneously transfer heat in a short time. = A metal with a wall thickness of 2 to 10 mm is used. As the metal, as described above, an alloy containing aluminum as a main component such as aluminum or duralumin is preferably used, and other metals having a thermal conductivity of 100 W / m · K or more can be used, such as copper, zinc, and copper. A metal such as magnesium can be exemplified.

As described above, in the molds 10 and 11, a thin metal is used in order to conduct heat uniformly in a short time, but the foamable resin mixture 2 arranged in the mold is molded. Since the molds 10 and 11 are arranged so as to be sandwiched between the two fiber-reinforced resin sheets 1, even if the wall thickness d of the molds 10 and 11 is thin, the function as a mold that gives the shape of the molded product can be sufficiently exhibited. ..

For heating and cooling in the steps (B) and (C), the left and right heated metal bodies 20 and 21 and the cooling metal bodies 30 and 31, respectively, are placed on the outer surfaces of the molds 10 and 11, respectively, using the mold having the above configuration. By bringing them into close contact with each other and conducting heat, the two molds 10 and 11 and the two fiber-reinforced resin sheets 1 arranged inside and the foamable resin mixture 2 are heated uniformly in a short time. It is cooling. The metals used for the heated metal bodies 20 and 21 and the cooled metal bodies 30 and 31 are not limited to the molds 10 and 11, and a metal block such as steel may be used as long as heat can be stored and heat can be dissipated by close contact. it can. However, it is necessary to provide and remove heat evenly on the left and right sides, and these metal bodies preferably have the same shape on the left and right sides, and preferably have the same heat capacity. The surface that is in close contact with the mold is preferably a smooth surface so as not to interfere with heat conduction due to close contact.

The heated metal bodies 20 and 21 need to be preheated to a required temperature before being brought into close contact with the molds 10 and 11, but the heating means for the heated metal bodies is heating in a heating furnace. Known means such as high frequency induction heating and radiant heating can be used. Then, the metal body may be provided with a heating means such as an electric heater or a conduit for a heat medium. On the other hand, the cooled metal bodies 30 and 31 may be kept at room temperature, but it is also effective to cool them in advance in order to cool them efficiently. The cooled metal bodies are provided with conduits for cooling water and cooling oil. May be good. However, when these heating / cooling means are provided on the heating or cooling metal body, it is necessary to adjust the contact surface with the mold so that there is no temperature variation, and the heating or cooling metal body is the heating / cooling means. By making the left and right heat capacities the same as a whole including the above, the amount of heat given by the heating means or the amount of heat removed by the cooling means is the same amount in the left and right molds.

Using the above dies 10 and 11 and the heated metal bodies 20 and 21, the two molded fiber-reinforced resin sheets 1 and the foamable resin mixture 2 set in the step (A) were placed in (B). By bringing the heated metal bodies 20 and 21 into close contact with the outer surfaces 10a and 11a of the left and right dies 10 and 11, the fiber reinforced resin sheet 1 is thermally deformed by being heated by heat conduction through the dies 10 and 11. The temperature of the filled foamable resin mixture 2 is raised to a temperature equal to or higher than the thermal expansion start temperature of the heat-expandable foam particles and to a temperature equal to or lower than the maximum expansion temperature. The heat-expandable foamed particles are expanded by this temperature rise, and the foamable resin mixture 2 is formed into a resin foamed sheet 3 and laminated and integrated with the fiber-reinforced resin sheet 1.

Next, in the step (C), the cooling metal bodies 30 and 31 are brought into close contact with the outer surfaces 10a and 11a of the left and right molds 10 and 11 instead of the heated metal bodies 20 and 21, and the cooling metal bodies 30 and 31 are brought into close contact with each other through the molds 10 and 11. After removing heat and cooling and cooling, the molds 10 and 11 are opened, and the laminated composite sheet 100 having the fiber reinforced resin sheet 1 as the skin layer and the resin foam sheet 3 as the core layer is taken out.

The temperature that does not cause thermal deformation is set based on the deflection temperature under load (heat distortion temperature) of the fiber-reinforced resin sheet 1, and is a temperature lower than this deflection temperature under load, preferably 5 ° C. or higher. Therefore, in the step (B), the effervescent resin mixture has a temperature that does not cause thermal deformation, and is set to a temperature equal to or higher than the thermal expansion start temperature of the thermally expandable foam particles mixed in the composition and not more than the maximum expansion temperature. The temperature is raised. The deflection temperature under load is specified by JIS K 7191-1 to 3.

As described above, the fiber-reinforced resin sheet 1 is obtained by impregnating the reinforcing fibers with a thermosetting resin or a thermoplastic resin as a matrix resin, or mixing chopped fibers obtained by cutting the reinforcing fibers with the matrix resin. It is a sheet formed by heating and pressurizing a fiber-reinforced thermosetting resin base material or a fiber-reinforced thermoplastic resin base material, and a sheet having a wall thickness in the range of 0.02 to 1.0 mm can be used.

Since the fiber-reinforced resin sheet 1 is fiber-reinforced, it can secure a sufficiently high deflection temperature under load as compared with the matrix resin itself. In the case of the fiber-reinforced thermosetting resin sheet, the foamable resin mixture 2 is in step (B). The foamable resin mixture 2 can be heated to a temperature higher than the heat distortion start temperature of the heat-expandable foam particles mixed in, and the foamable resin mixture 2 can be used as the resin foam sheet 3. Further, even in the case of a fiber-reinforced thermoplastic resin sheet using a thermoplastic resin as a matrix resin, the temperature at which the sheet does not undergo thermal deformation is higher than the thermal expansion start temperature of the heat-expandable foam particles mixed in the foamable resin mixture. Can be secured.

Further, the heat-expandable foamed particles mixed in the foamable resin mixture 2 are particles in which a foam-expanding agent is enclosed inside a shell forming the surface of the particles as described above, and are heat-expandable microcapsules (or). Various types are commercially available as thermal expansion microspheres), and the thermal expansion start temperature is 115 to 140 ° C from the low to medium temperature expansion type with a thermal expansion start temperature of 80 to 110 ° C and a maximum expansion temperature of 115 to 140 ° C. There is a medium-high temperature expansion type with a maximum expansion temperature of 170 to 200 ° C, and an ultra-high temperature expansion type with a thermal expansion start temperature of 180 to 230 ° C and a maximum expansion temperature of 210 to 275 ° C is also commercially available. .. Therefore, the type of heat-expandable foamed particles can be selected in consideration of the deflection temperature under load of the fiber-reinforced resin sheet to be used, and the heating temperature of the foamable resin mixture 2 (heating temperature of the mold) can be selected.

As the reinforcing fiber used for the fiber-reinforced thermocurable resin base material or the fiber-reinforced thermoplastic resin base material, glass fiber, carbon fiber, aramid fiber and the like are preferably used, and the boron fiber, ceramic fiber, silicon carbide fiber and the like are preferably used. It may be. The thermosetting resin as the matrix resin is epoxy resin, unsaturated polyester resin, silicone resin, allyl resin, melamine resin, phenol resin, furan resin, etc. Similarly, the thermoplastic resin is polypropylene (PP), polyethylene terephthalate ( PET), polybutylene terephthalate (PBT), polyamide (PA), polyacetal (POM), polycarbonate (PC), polyhydroxypolyether (phenoxy resin), acrylonitrile-butadiene-styrene copolymer (ABS), polyphenylene sulfide (PPS) ), Polyetheretherketone (PEEK) and the like can be exemplified.

In FIG. 1, an example in which the sheet shape formed as a laminated composite sheet is flat is shown, but the sheet may be not only flat but also the sheet shape formed as shown in FIG. 2 may be curved. .. In this case, as shown in FIG. 2D, the fiber reinforced resin sheets 4 and 5 are formed into a curved surface, and the dies 14 and 15 having the same curved surface are used. The inner surfaces 14b and 15b of the molds 14 and 15 coincide with the curved surface of the fiber reinforced resin sheet 4 on the concave side of the curved surface and the curved surface of the fiber reinforced resin sheet 5 on the convex side of the curved surface. Similar to FIG. 1, the gaps between the fiber-reinforced resin sheets 4 and 5 are filled with the foamable resin mixture 2, and then the dies 14 and 15 are brought into close contact with each other on the parting surface 17 as shown in (E). To do. In this case, the cavity 16 is designed so that the gap between the fiber-reinforced resin sheets 4 and 5 filled with the foamable resin composition 2 has a gap width t. Similar to FIG. 1, the wall thickness of the mold, which is the distance between the outer surfaces 14a and 15a of the molds 14 and 15, and the inner surfaces 14b and 15b, is unified with d.

In addition, the configurations and operations of the dies 14 and 15 are as described with respect to the dies 10 and 11 of FIG. 1, and the fiber reinforced resin sheets 4 and 5 are the same as those of the fiber reinforced resin sheet 1 and have a curved surface. It is only the difference between being molded in a shape and being molded in a flat shape. The contact surface of the heated metal body and the cooled metal body is a curved surface that matches the outer surface of the mold.

Hereinafter, examples will be shown in order to specifically explain the present invention.

[Example 1]
As a fiber reinforced resin base material, carbon fiber reinforced epoxy resin preprig (resin content 33%) prepared by impregnating carbon fiber cloth (carbon fiber woven fabric) with a 130 ° C-curing type epoxy resin varnish is used for hot press molding. It was formed into a sheet having a wall thickness of 0.15 mm to obtain a fiber reinforced resin sheet. The deflection temperature under load of this fiber reinforced resin sheet was 200 ° C. or higher.
As the heat-expandable foamed particles, commercially available heat-expandable microcapsules "Expansel (registered trademark, Axonobel Chemicals) type 031-40, thermal expansion start temperature 80-95 ° C, maximum expansion temperature 120-135 ° C, average A foamable resin mixture obtained by mixing 2 parts by weight of "particle size 10-16 μm" with 100 parts by weight of a room temperature curing type epoxy resin varnish using an aliphatic polyamine as a curing agent was applied to the two fiber resin reinforced resin sheets. The two resin sheets are overlapped with the coated surface on the inside, and the gap t between the two resin sheets is 0.5 mm. As shown in FIG. 1 (A), a pair of left and right plates having a wall thickness d of 3 mm. Using an aluminum mold, the left and right molds were set by arranging them in the cavity.

Next, two steel-heated metal bodies of the same shape with a thickness of 60 mm heated to 110 ° C. in a heating furnace were placed on the outer surfaces of the left and right molds for 90 minutes as shown in FIG. 1 (B). The heat molding was performed in close contact with each other. Then, the heated metal body was removed, and a steel cooling metal body having the same shape at room temperature was brought into close contact with the outer surface of the mold for 20 minutes to be cooled, and then the laminated composite sheet formed from the mold was taken out. The laminated composite sheet is a laminated composite sheet having a carbon fiber reinforced resin sheet as a skin layer of 0.15 mm and a resin foam sheet as a core layer of 0.5 mm, and is a flat plate having a wall thickness of 0.8 mm without warping or distortion. A sheet was obtained.

[Example 2]
As the fiber reinforced resin base material, a glass fiber reinforced polypropylene base material (resin content 50%) obtained by impregnating plain woven glass cloth with polypropylene was used, and a fiber reinforced resin sheet formed to a wall thickness of 0.30 mm by hot press molding ( (Load deflection temperature of 120 ° C. or higher) and 2 parts by weight of the heat-expandable particles used in Example 1 are mixed with 100 parts by weight of a room temperature curing type unsaturated polyester resin using methyl ethyl ketone-based polypropylene as a curing agent and styrene as a monomer. Using the foamed resin mixture obtained, the gap t between the two fiber-reinforced resin sheets was set to 1.0 mm, and the temperature of the steel heated metal body was set to 100 ° C. A laminated composite sheet having a glass fiber reinforced resin sheet as a skin layer of 0.30 mm and a resin foam sheet as a core layer of 1.0 mm, and a flat plate-like sheet having a wall thickness of 1.6 mm without warping or distortion was obtained. ..

[Example 3]
As a fiber reinforced material, a polymerized thermoplastic prepreg "NS-TEReg (registered trademark, Nittetsu Chemical & Materials Co., Ltd.)" in which a carbon fiber woven fabric is impregnated with a curing agent oil-containing phenoxy resin is used and heat-pressed at 160 ° C. A fiber-reinforced resin sheet that has been primary-cured by processing and molded into a sheet with a wall thickness of 0.15 mm, and a commercially available thermoplastic microcapsule "Expansel (registered trademark, Axonobel Chemicals)" as a thermoplastic foamed particle. Type 053-40, thermal expansion start temperature 96-103 ° C, maximum expansion temperature 138-146 ° C, average particle size 10-16 μm ”2 parts by weight, room temperature curing type epoxy resin varnish 100 using aliphatic polyamine as a curing agent Using the foamable resin mixture mixed in the weight part, the carbon fiber reinforced resin sheet was formed in the same manner as in Example 1 except that the temperature of the steel heated metal body was 120 to 130 ° C., and the carbon fiber reinforced resin sheet was 0.15 mm. A laminated composite sheet having a skin layer and a resin foam sheet as a core layer of 0.5 mm, and a flat plate-like sheet having a wall thickness of 0.8 mm without warping or distortion was obtained. This flat sheet can be further subjected to secondary processing by hot press processing using a mold to obtain a molded product in which the phenoxy resin is completely cured.

[Example 4]
The fiber-reinforced resin sheet molded in Example 2 and 2 parts by weight of the heat-expandable particles used in Example 1 were added to 100 parts by weight of PVC paste (100 parts by weight of PVC fine powder resin / 60 parts by weight of DOP). Using the mixed foamable resin mixture, the two fiber-reinforced resin sheets were molded in the same manner as in Example 1 except that the gap between the two fiber-reinforced resin sheets was 1.0 mm and the temperature of the steel heated metal body was 100 ° C. A laminated composite sheet having a glass fiber reinforced resin sheet as a skin layer of 0.30 mm and a resin foam sheet as a core layer of 1.0 mm, and a flat plate-like sheet having a wall thickness of 1.6 mm without warping or distortion was obtained. ..

[Example 5]
A pair of left and right aluminum molds having a wall thickness d of 3 mm used in Example 1 are heated using an aluminum mold having a curved shape as shown in FIG. 2, which has the same shape as the curved curved surface of the mold. And, except that the heated metal body made of cooled steel is used, molding is performed by the same operation as in Example 1, and the molded curved surface coincides with the cavity surface of the mold, and the carbon fiber reinforced resin sheet is skinned with 0.15 mm. A laminated composite sheet having a resin foam sheet as a core layer of 0.5 mm as a layer, and a curved sheet having a wall thickness of 0.8 mm without abnormal warpage or distortion was obtained.

1 Fiber reinforced resin sheet 4 Fiber reinforced resin sheet (curved surface)
2 Foamable resin mixture 5 Fiber reinforced resin sheet (curved surface)
3 Resin foam sheet 100 Laminated composite sheet 10, 11 Mold (flat surface) 14, 15 Mold (curved surface)
10a, 11a Outer surface 14a, 15a Outer surface 10b, 11b Inner surface 14b, 15b Inner surface 12 Cavity 16 Cavity 13 Parting surface 17 Parting surface 20, 21 Heating metal body 30, 31 Cooling metal body d Mold wall thickness t Fiber Gap width of reinforced resin sheet

Claims (6)

Two molded fiber-reinforced resin sheets are brought into close contact with each inner surface of a pair of dies made of a metal having a high coefficient of thermal coefficient and having a uniform and the same wall thickness, and the gaps between the fiber-reinforced resin sheets are made uniform. The pair of molds were set in a state where the gap was filled with a foamable resin mixture in which thermal expansion foam particles were uniformly mixed, and then the outer surface of each of the molds was covered with a heated metal. The temperature at which the fiber-reinforced resin sheet is not thermally deformed by bringing the bodies into contact with each other and simultaneously heating from both outer surfaces, and the filled foamable resin mixture is equal to or higher than the thermal expansion start temperature of the heat-expandable foam particles. The temperature is raised below the maximum expansion temperature to expand the heat-expandable foam particles, the foamable resin mixture is formed into a resin foam sheet, laminated and integrated with the fiber-reinforced resin sheet, and then cooled metal is replaced with a heated metal body. A method for producing a laminated composite sheet in which a fiber-reinforced resin sheet is used as a skin layer and a resin foam sheet is used as a core layer, in which a die and a laminated and integrated sheet are simultaneously cooled from both outer surfaces by bringing the bodies into contact with each other. The method for producing a laminated composite sheet according to claim 1, wherein the mold is made of aluminum or an alloy containing aluminum as a main component. The laminated composite according to claim 1 or 2, wherein the foamable resin mixture is a liquid or paste-like thermosetting resin or a mixture in which heat-expandable foamed particles are uniformly mixed with a thermoplastic resin. Sheet manufacturing method. The method for producing a laminated composite sheet according to claim 3, wherein the foamable resin mixture does not defoam bubbles generated when the heat-expandable foamed particles are uniformly mixed. The laminated composite sheet according to any one of claims 1 to 4, wherein the heat-expandable foamed particles are particles in which a volatile solvent is sealed inside a shell made of a thermoplastic resin. Manufacturing method. The item according to any one of claims 1 to 5, wherein the fiber-reinforced resin sheet is a sheet formed by heating and pressurizing a fiber-reinforced thermosetting resin base material or a fiber-reinforced thermoplastic resin base material. The method for manufacturing a laminated composite sheet according to the description.

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