JP2009012450A - Two-step molding method for composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-step molding method for a composite material where molding can be facilitated, and further, a molded article can be manufactured at high precision. <P>SOLUTION: The molding method comprises: a step where a stock obtained by kneading a thermoplastic resin of 40 to 15 wt.% to a fiber raw material, an inorganic raw material or a metal raw material of 60 to 85 wt.%, and performing solidification is crushed, so as to prepare a composite intermediate raw material; a step where the composite intermediate raw material is pushed in and/or decompression-sucked using an air flow, and is packed into a prescribed molding die; and a step where the composed intermediate raw material made close together into the molding die is heated and pressurized, so as to be compressed and integrated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a two-stage molding method of a composite material in which a composite raw material obtained by mixing and molding is crushed to form a composite intermediate material.

  As a molding method of composite materials, for example, fiber reinforced plastic FRP, in addition to the hand lay-up method and spray-up method in which fiber aggregates are laid on the mold and the resin mixed with the curing agent is delaminated and delaminated, SMC press method in which a sheet of aggregate and resin mixed in advance is compression-molded with a mold. Members (prepreg, etc.) that have been pre-mixed with fibers and matrix (adhesive) in a large kiln (autoclave) There is a method to “bake and harden”. However, since it is molded in a state in which different kinds of materials are mixed and the thermosetting resin is used as a matrix resin, it is disadvantageous that recycling is almost impossible.

  Therefore, in recent years, as an alternative to glass fiber reinforced resin (GFRP), there are also announcements using recyclable thermoplastics such as methyl methacrylate. However, as described above, if the thermosetting resin is not used as a matrix, it has a predetermined strength. Is difficult to obtain, and when a thermoplastic resin is used, it is a special production method. For example, there is stampable sheet molding using a fiber reinforced thermoplastic resin sheet. This method is a sheet manufacturing method that is different from the conventional method by using a "split flying device", and supplies continuous reinforcing fibers (robbing) and thermoplastic resin fibers (sliver) simultaneously. This is a method of continuously producing a composite mat in which fibers are cut, split, and mixed in a device and both fibers are uniformly mixed (National Institute of Advanced Industrial Science and Technology). However, since it lacks versatility, it is not practical. On the other hand, as a recycling method, automobile interior materials using FRP substrates are used as recycled materials, thermoplastic resin pellets are used as matrix materials, and recycled materials and matrix materials are reduced to 10 mm or less by the grinding process. The pulverized regenerated raw material and the matrix raw material are agitated by the stirring and mixing step, and the stirred regenerated raw material and the matrix raw material are mixed together by rubbing them together. And the matrix raw material are rubbed together to reduce the volume, and then the recycled raw material and the matrix raw material reduced in volume are put into the extruder 2 together, and the recycled product R obtained by melting and integrating the recycled raw material and the matrix raw material is obtained. Only a method for recycling an automotive interior material to be extruded has been proposed (Patent Document 1).

JP 2006-264060 A

As a result of diligent research, the present inventor usually has a fiber filling amount for resin reinforcement of about 40% by weight at most with respect to the thermosetting resin due to limitations due to molding technology. On the other hand, if a thermoplastic resin is used as a matrix and the filling amount of reinforcing fibers therein is 60% by weight or more, which is not normally considered, a physical property comparable to FRP using a thermosetting resin as a matrix can be obtained. Although it has been found that when the filling amount of the matrix is 60% by weight or more, ordinary extrusion molding is completely impossible. Even if the SMC pressing method (Sheet Molding Compounds) is used, it is difficult to prepare a predetermined SMC sheet (a sheet, which is obtained by kneading a base material, a resin, and a filler).
Therefore, as a result of diligent research, the present inventor has made it possible to directly mold a molded product having a fiber filling amount of 60% by weight or more, but when using a thermoplastic resin, the fiber reinforced composite once kneaded and solidified. When the material is pulverized or crushed and used as a molding intermediate material, and two-stage molding is performed, a fiber content of 60% by weight or more, preferably 70% by weight or more and 85% by weight can be blended, and this is molded. Then, it has been found that the fiber orientation is random and overlaps vertically, and that an extremely ideal fiber reinforced resin product can be produced even when a thermoplastic resin is used as the matrix resin. However, it is necessary to prepare a composite intermediate piece formed by kneading and solidifying primary resin by kneading and solidifying 40 to 15% by weight of a thermoplastic resin to 60 to 85% by weight of incombustible fiber raw material. In addition, when filling a predetermined mold and heating and pressurizing it, there is no choice but to fill the mold manually and there is a problem in molding efficiency.

In view of the current situation, the present inventor has been made by paying attention to the fact that if the composite intermediate piece formed by crushing is given air permeability, it can be sequentially deposited and filled in a mold by placing it on an air flow. ,
The present invention provides a composite intermediate material that is permeable to air flow by crushing a solidified material obtained by kneading 40 to 15% by weight of a thermoplastic resin with 60 to 85% by weight of a fiber material or inorganic material. A step of pushing the composite intermediate material using an air flow and / or suctioning it under reduced pressure to fill it into a predetermined mold, and compressing and integrating the composite intermediate material densely packed in the mold A two-stage molding method of a composite material, characterized by comprising the step of: In particular, in the process of filling into the mold, the mold is provided with an inlet for introducing the composite intermediate material together with the air flow, while the mold is provided with an air flow outlet, and the composite intermediate material is formed into the mold with the air flow. While discharging, the exhaust is exhausted from the exhaust port, and the composite intermediate material is sequentially deposited and filled from the downstream side to the upstream side in the molding die. Instead of this, in the step of filling into the molding die, a pair of molding dies are formed. It is also possible to decompress the inside of the mold, open the material inlet, and suck and fill the composite intermediate material into the mold.

  According to the present invention, the composite intermediate material obtained by crushing the primary molding material highly filled with fiber or inorganic material is filled with air in the molding die, and this is heated and pressurized to be compressed and integrated. A composite product highly filled with an inorganic material can be automatically filled and automatically formed without using manual work, so that the work efficiency is excellent and the production cost can be reduced.

In the present invention, not only combustible fibers but also non-combustible reinforcing fibers such as glass fibers, carbon fibers, and fiber boron are selected as the fiber raw material. As the inorganic raw material, various raw materials such as aluminum hydroxide, silica, tankal, and carbon are selected. Various thermoplastic resins may be selected as the thermoplastic resin depending on the application, and the thermoplastic resin is adjusted in relation to the type of reinforcing fiber, dimensions, filling amount, and the like. For example, PP (polypropylene), PC (polycarbonate) polyamide resin and the like are preferable for structural materials such as automobile bodies and small ship hull materials. Further, for the purpose of improving the kneadability with the reinforcing fiber, two or more thermoplastic resins that are compatible can be blended and adjusted. Therefore, according to the present invention, a composite material composed of aluminum hydroxide powder 60 to 75% as an inorganic raw material and polylactic acid 40 to 25% as a thermoplastic resin is kneaded and crushed after solidification. The heat resistant composite product can be manufactured by molding by the above method.
According to the present invention, a composite material comprising 60 to 85% rare earth magnet powder as an inorganic raw material and 40 to 15% polyamide resin as a thermoplastic resin is kneaded, crushed after solidification, and It can be molded by the method to produce a plastic magnet product.
Furthermore, according to the present invention, a composite material composed of 60 to 85% carbon fiber as a fiber raw material and 40 to 15% polycarbonate resin as a thermoplastic resin is kneaded and solidified and molded by the method of claim 1. The structure composite product can be manufactured.

  When coloring a molded article molded according to the present invention, 40 to 15 wt% of a transparent or translucent thermoplastic resin is kneaded with one or two or more colored 60 to 85 wt% fiber raw materials. It is preferable to prepare a crushed piece of a fiber reinforced material solidified and color the fiber raw material. It is also possible to prepare crushed pieces of a fiber reinforced material obtained by kneading and solidifying a thermoplastic resin colored in the same system with a colored fiber raw material, and the crushed pieces are two or more different colored materials There is also.

  A feature of the present invention is that a kneaded and solidified composite material is pulverized or crushed, filled with air in a mold, heated and pressurized to produce a thin sheet, a slightly thick plate-shaped or three-dimensional composite resin molded product. It is in the point made. When the reinforcing fiber contains moisture, it may be heated with another heat source to evaporate the contained moisture before kneading with the molten matrix resin, or the molten matrix resin and a plurality of reinforcing fibers are kneaded. At this time, the reinforcing fibers may be heated by the heat of the matrix resin to evaporate the moisture contained in the reinforcing fibers. If it does in this way, the drying process of a reinforcement fiber is not required separately, but a manufacturing process can be simplified.

  When recycling used fiber material, the recovered fiber material is crushed into an appropriate size, for example, a size that allows the three-dimensional shape of the fiber to remain, for example, 5 mm to 20 mm on a side, and an appropriate heat source. The matrix resin can be softened or melted by heating, and if necessary, the matrix resin can be added and used as all or part of the raw material of the fiber material.

  When a surface resin layer is formed on a composite resin molded product, it may be formed by stacking a softened or melted synthetic resin material on the surface of the composite resin molded product, or a synthetic resin film, sheet or plate is laminated. Can also be formed. The surface resin layer of the composite resin molded product may be formed on the entire outer surface of the composite resin molded product, or may be formed only on a part of the outer surface, for example, the upper surface or the lower surface of the plate-shaped composite resin molded product.

  Composite resin molded products can be molded into a predetermined product shape by forming a surface resin layer, but a synthetic resin film, sheet or plate is laminated on the surface of the composite resin molded product, or softened or melted. When the synthetic resin materials are stacked, they can be molded into a predetermined product shape. For molding this composite resin molded product, a die, a roller, or the like is used, and drawing molding, bending molding, vacuum molding, pressure molding, match molding, or the like can be employed.

  The synthetic resin film, sheet or plate and the composite resin molded product may be bonded to each other by an adhesive, and bonded to each other depending on the affinity between the matrix resin of the composite resin molded product and the synthetic resin material of the surface resin layer. You may make it do.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. FIG. 1 shows a preferred embodiment of a method for producing a renewable fiber-reinforced resin product according to the present invention. When manufacturing fiber reinforced resin products, various reinforcing fiber materials are prepared. In addition to long fibers and short fibers, the reinforcing fibers may be powdery having an average outer diameter of 10 μm to 35 μm. Also, a resin, for example, a thermoplastic resin such as an appropriately sized chip-shaped polypropylene or polyethylene is prepared. These resins may be one kind or a mixture of two kinds.

  On the other hand, the heater of the kneading machine 10 is operated, and the inside of the kneading machine 10 is raised to a melting temperature of the thermoplastic resin, for example, a temperature in the range of 100 ° C. to 300 ° C., and FIG. As shown, the crushed thermoplastic resin chips are put into the kneader 10 and melted with stirring. Binder resin chips may be charged at once, or may be divided into a plurality of times. When heat is generated by stirring the molten resin by rotation of the stirring blade during melting of the binder resin, the heating temperature by the heater may be slightly lower than the melting temperature of the binder resin.

  When the thermoplastic resin is sufficiently softened or melted, the prepared fiber raw material, for example, glass fiber, is fed into the kneader 10 in one time or a plurality of times, and the colorant, for example, the paint is divided in one time or a plurality of times. Then, the mixture is put into the kneader 10 and the softened and melted thermoplastic resin, the filler and the colorant are kneaded so as to be substantially uniform. If a large amount of filler is added at a time, the temperature of the softened and melted resin may decrease. Therefore, the raw material of the fiber reinforced material is preliminarily set to an appropriate temperature with a heater or the like before being added to the kneader 10. You may heat.

  Further, if the thermoplastic resin is heated for a long time in a molten state, the original physical properties of the resin may be impaired. Therefore, it is preferable to complete the kneading in a short time after sufficiently melting. According to the experiments of the present inventors, it has been found that the time from melting to completion of kneading is preferably about 5 to 30 minutes. However, the optimum time varies depending on the heating temperature and the physical properties of the thermoplastic resin. Should be obtained by experimentation.

  When sufficient kneading is completed, as shown in FIGS. 1B and 1C, the kneaded product 20 is taken out, and a fiber having an appropriate size, for example, a size of 10 mm to 40 mm on one side, is projected by the crusher 11. Crush into scales. The size of the crushed piece 21 is not particularly limited because it is made to flow by pressurization in a later process, but it is preferable to have a shape that easily floats in the air flow because it is placed in the air flow and filled in the mold. It is important to make the whole air permeable.

  Similarly, as shown in FIG. 1 (d), crushed pieces 21 of different colors, for example, white, black, brown and blue, are manufactured.

  When a plurality of crushed pieces 21 are thus obtained, they are filled into a molding surface, for example, a pair of heated dies 30 and 31 as shown in FIG. Here, the inside of the mold is sucked and depressurized through the exhaust port 32, then the exhaust port 32 is closed, and the composite intermediate piece 21 is sucked and filled from the suction port 33. Thereafter, vibration is applied to stabilize the packing density, and heating and pressurization are performed at that position. Then, the thermoplastic resins having different colors are compressed to ¼ to ５ while flowing, and are integrated with each other. When the temperature is lowered and then taken out and the surface is polished, the result is shown in FIG. Thus, a fiber reinforced resin product that seems to be a polished surface pattern is obtained, and a resin layer is formed on the surface.

In the present invention, in the step of filling the molding die so that the crushed pieces can be filled in the molding die by being placed on the air stream, the upper side of the molding die is used as the air flow inlet, while the lower side of the molding die is A composite intermediate material that is permeable to the air flow is introduced into the mold together with the air flow and exhausted from below, and the intermediate material is sequentially deposited from below to above in the mold to be filled. . Specifically, for example, a cyclone method may be used in which crushed pieces are suspended in a rotating air stream as a filling machine, and are sequentially sent out and accumulated.

FIG. 2 shows a preferred embodiment of a method for producing a heat-resistant resin product in which an inorganic material is highly filled. Here, aluminum hydroxide is prepared as a heat resistance imparting agent. This inorganic material is usually a powder. On the other hand, as the resin, a thermoplastic resin such as a chip-shaped polypropylene or polyethylene having an appropriate size can be used. Here, polylactic acid is prepared. You may mix suitably other resin with polylactic acid.

  On the other hand, the heater of the kneading machine 10 is operated, and the inside of the kneading machine 110 is raised to the melting temperature of the thermoplastic resin, for example, a temperature in the range of 100 ° C. to 300 ° C., and FIG. As shown, the crushed thermoplastic resin chips are put into the kneader 110 and melted with stirring. Binder resin chips may be charged at once, or may be divided into a plurality of times. When heat is generated by stirring the molten resin by rotation of the stirring blade during melting of the binder resin, the heating temperature by the heater may be slightly lower than the melting temperature of the binder resin.

  When the thermoplastic resin is sufficiently softened or melted, the prepared aluminum hydroxide is fed into the kneading machine 110 at once or divided into a plurality of times, and the colorant, for example, the paint is divided into a kneading machine at once or a plurality of times. The mixture is poured into 110, and the softened and melted thermoplastic resin, the filler and the colorant are kneaded so as to be substantially uniform. If a large amount of filler is added at once, the temperature of the softened and melted resin may decrease. Therefore, the raw material of the fiber reinforced material is previously set to an appropriate temperature with a heater or the like before being charged into the kneader 110. You may heat.

  Further, if the thermoplastic resin is heated for a long time in a molten state, the original physical properties of the resin may be impaired. Therefore, it is preferable to complete the kneading in a short time after sufficiently melting. According to the experiments of the present inventors, it has been found that the time from melting to completion of kneading is preferably about 5 to 30 minutes. However, the optimum time varies depending on the heating temperature and the physical properties of the thermoplastic resin. Should be obtained by experimentation.

  After sufficient kneading, as shown in FIGS. 2 (b) and 2 (c), the kneaded product 20 is taken out and crushed into an appropriate size by a crusher 111, for example, a scale having a side of 3 mm to 20 mm. To do. The size of the crushed piece 121 is not particularly limited because it is made to flow by pressurization in a later process, but it is preferable to have a shape that easily floats in the air flow because it is placed in the air flow and filled in the mold. It is important to devise so that the whole can be permeated with air and the mold is appropriately evacuated so that the material is uniformly deposited every corner.

  Similarly, as shown in FIG. 2D, crushed pieces 121 of different colors, for example, white, black, brown, and blue are manufactured.

  In this way, when the crushed pieces 121 of a plurality of colors are obtained, a mold 50 is prepared by opening a pair of vertical molds 51 and 52, for example, as shown in FIG. Here, the crushed pieces 121 are filled into the mold 50 together with the air flow through the filling port 53. Specifically, in the step of filling the mold, a pair of molds are provided with an inlet for introducing the composite intermediate raw material together with the air flow, while the air flow is discharged to a predetermined place in the other direction of the mold if necessary. An outlet is provided, and the composite intermediate material is introduced into the mold together with the air flow, while being exhausted from the exhaust port, and the composite intermediate material is sequentially deposited and filled from the downstream side to the upstream side of the air flow in the mold. Next, vibration or the like is applied to stabilize the packing density, and heating and pressurization are performed at that position. Then, the thermoplastic resins having different colors are compressed to about 1/3 while flowing and are integrated with each other, and when the temperature is lowered and taken out and the surface is polished, as shown in FIG. Resin products that look like polished surfaces can be obtained. In this embodiment, the vertical mold is left as it is for compression molding, but it can also be laid horizontally and compressed.

Hereinafter, other composite intermediate materials will be described in detail.
When carbon fiber is used as the raw material for the fiber reinforced material, one having an average length of 5 to 15 mm is used. On the other hand, an appropriate size of polycarbonate is prepared as a matrix resin. From this, for example, a composite intermediate piece is prepared by crushing into thin pieces each having a size of 3 mm to 20 mm. Such a composite material is provided with sufficient structural strength by highly filled carbon fiber, and can be used for structural materials for automobiles and ships.

  Also, instead of polycarbonate (PC), polypropylene (PP) / ethylene / vinyl acetate copolymer (EVA) resin is used, glass fiber is used as the reinforcing fiber, glass fiber 80% by weight, PP 15% by weight, EVA 5% by weight A composite resin plate having an extremely smooth surface can be obtained.

It is a figure which shows typically 1st Embodiment which shows the two-stage molding method of the fiber reinforced resin molded product which concerns on this invention. It is a figure which shows typically 2nd Embodiment which shows the two-stage manufacturing method of the inorganic highly filled molded article which concerns on this invention.

Explanation of symbols

10, 110 Kneading machine 11, 111 Crusher 30, 31, 51, 52 Mold 20, 120 Composite material 21, 121 Shredded piece 40, 60 Composite product

Claims (7)

  A step of preparing a composite intermediate material by crushing a solidified material obtained by kneading 40 to 15% by weight of a thermoplastic resin with 60 to 85% by weight of a fiber raw material, an inorganic raw material or a metal raw material; A step of filling in a predetermined mold by pressing and / or suctioning under reduced pressure using an air stream, and a step of compressing and integrating a composite intermediate material densely packed in the mold by heating and pressing. A two-stage molding method for composite materials.   In the step of filling in the mold, a pair of molds are provided with an inlet for introducing the composite intermediate raw material together with the air flow, while an air flow outlet is provided in the mold and the composite intermediate raw material is formed into the mold with the air flow. 2. The two-stage molding method for a composite material according to claim 1, wherein the composite material is exhausted from one exhaust port while being charged, and the composite intermediate raw material is sequentially deposited from the downstream side to the upstream side in the molding die.   2. The composite material according to claim 1, wherein in the step of filling in the mold, the inside of the mold formed by the pair of molds is depressurized, and in this state, the material input port is opened to suck and fill the composite intermediate material into the mold. Two-stage molding method. 2. The two-stage molding method of a composite material according to claim 1, wherein the compression ratio in the step of compressing and integrating the composite intermediate raw material densely packed in the mold is 1/3 or more.   A composite intermediate material obtained by kneading a composite material comprising 60 to 75% of aluminum hydroxide powder as an inorganic raw material and 40 to 25% of polylactic acid as a thermoplastic resin, and crushing after solidification is obtained by the method of claim 1. Molded heat-resistant composite product. A composite intermediate material obtained by kneading a composite material composed of 60 to 85% rare earth magnet powder as an inorganic raw material and 40 to 15% polyamide resin as a thermoplastic resin, and crushing after solidification is formed by the method of claim 1. Plastic magnet products. A composite intermediate material obtained by kneading a composite material composed of 60 to 85% carbon fiber as a fiber raw material and 40 to 15% polycarbonate resin as a thermoplastic resin, and crushing after solidification is formed by the method of claim 1. Structure composite product.

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