JP2015160349A - Manufacturing method of fiber reinforced plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fiber-reinforced plastic, in which defects such as a poor outer appearance, meanders of a fiber and warpage can be restrained from being developed in the fiber-reinforced plastic to be obtained.SOLUTION: The method for producing the fiber-reinforced plastic comprises the steps of: impregnating a reinforcing fiber with a thermoplastic resin to obtain a prepreg base material; piling up two or more pieces of the prepreg base materials to obtain a prepreg laminate; heating the prepreg laminate in a heating device 100; and cooling/pressing the heated prepreg laminate in a cool press machine 130. A temperature Th(°C) of the prepreg laminate 10 when heated and a temperature Tc(°C) of the prepreg laminate 10 when cooled/pressed are controlled so that the inequalities: Tm+10≤Th≤Tm+100, Tm-100≤Tc≤Tm-10 and 20≤Th-Tc≤110 (on condition that Tm(°C) is the melting point of the thermoplastic resin or the glass transition temperature thereof when the thermoplastic resin has not the melting point) are satisfied.

Description

  The present invention relates to a method for producing a fiber reinforced plastic.

  In various fields such as aircraft members, automobile members, wind turbine members for wind power generation, and sports equipment, structural materials formed by stamping molding sheet-like fiber reinforced plastics are widely used. The fiber reinforced plastic is formed, for example, by stacking and integrating a plurality of prepreg base materials in which a reinforced fiber is impregnated with a thermoplastic resin.

  Examples of the prepreg base material include those obtained by impregnating a thermoplastic resin with a continuous reinforcing fiber having a long fiber length in one direction and impregnating it with a thermoplastic resin. With a fiber reinforced plastic formed with a prepreg base material using such continuous long reinforcing fibers, a structural material having excellent mechanical properties can be produced. Moreover, when laminating the prepreg base material, mechanical properties can be appropriately designed by regularly arranging the reinforcing fibers in each prepreg base material. For example, by laminating so that the fiber axis direction of the reinforcing fiber of each prepreg base material is quasi-isotropic such as 0 °, 45 °, 90 °, −45 °, etc., isotropic mechanical properties Can be a good fiber reinforced plastic. Moreover, it can be set as the fiber reinforced plastic with the high mechanical physical property of the said direction by making the direction of the fiber axis of the reinforcing fiber of the prepreg base material laminated | stacked deviate in a specific direction.

  In addition, a method is known that uses a prepreg base material in which a reinforced fiber aligned in one direction is impregnated with a thermoplastic resin and a cut is formed so as to intersect the fiber axis. Since the fiber reinforced plastic using the prepreg base material has good fluidity at the time of shaping because the reinforcing fibers are shortly divided, it can be molded in a short time and can be formed into a complicated shape such as a three-dimensional shape. It can be particularly suitably used for shaping.

As a method for producing fiber reinforced plastic, for example, the following methods are known.
A prepreg laminate in which two or more notched prepreg base materials impregnated with a copolymerized polyamide resin (melting point 155 ° C.) as a thermoplastic resin are heated to 200 ° C. with a heating die press molding machine, and the mold cannot be opened. (Patent Document 1) A method for obtaining a flat fiber-reinforced plastic by cooling to a low temperature.

JP 2008-207545 A

  However, in the conventional method such as Patent Document 1, in the fiber reinforced plastic obtained, there are cases where the appearance is deteriorated, the fibers meander, the resin leaks or warps, and the like occur.

  An object of this invention is to provide the manufacturing method of the fiber reinforced plastic which can suppress that malfunctions, such as an external appearance defect, a fiber meandering, and a curvature, are produced in the fiber reinforced plastic obtained.

The method for producing a fiber reinforced plastic according to the present invention is a method for producing a fiber reinforced plastic by heating a prepreg laminate in which two or more prepreg base materials in which a reinforced fiber is impregnated with a thermoplastic resin are laminated and then heating and cooling. The temperature Th (° C.) of the prepreg laminate during heating and the temperature Tc (° C.) of the prepreg laminate during cooling press are controlled so as to satisfy the following conditions (1) to (3). Is the method.
(1) Tm + 10 ≦ Th ≦ Tm + 100
(2) Tm-100 ≦ Tc ≦ Tm-10
(3) 20 ≦ Th−Tc ≦ 110
(However, Tm (° C.) represents the melting point of the thermoplastic resin, or the glass transition temperature when it does not have a melting point.)

In the manufacturing method of the fiber reinforced plastic of this invention, it is preferable to arrange | position a metal plate or a resin sheet to the lower surface of the said prepreg laminated body, or both a lower surface and an upper surface, and to perform the said heating and cooling press.
Moreover, it is preferable to perform the said heating and cooling press in the state as it is, without arrange | positioning anything on both surfaces of the said prepreg laminated body.
Moreover, it is preferable to perform the said heating and cooling press in the state which pinched | interposed the said prepreg laminated body with a pair of metal mold | die.
Moreover, it is preferable to press the prepreg laminate when the heating is performed.
The reinforcing fibers in the prepreg base material are preferably aligned in one direction.
Moreover, it is preferable that the notch is formed in the reinforcing fiber of the prepreg base material.

  According to the method for producing a fiber reinforced plastic of the present invention, it is possible to suppress occurrence of defects such as poor appearance, fiber meandering, resin leakage, warpage, and the like in the obtained fiber reinforced plastic.

It is the side view which showed a mode that the metal plate was arrange | positioned to the upper surface and lower surface of a prepreg laminated body. It is a schematic diagram which shows an example of embodiment of the manufacturing method of the fiber reinforced plastics of this invention. It is a schematic diagram which shows an example of embodiment of the manufacturing method of the fiber reinforced plastics of this invention.

In the present specification, the temperature Th of the prepreg laminate upon heating means the temperature that the prepreg laminate reaches when the prepreg laminate is heated, that is, the temperature of the prepreg laminate immediately after heating. The temperature Th of the prepreg laminate at the time of heating is measured by inserting a temperature sensor such as a thermocouple near the center in the thickness direction of the prepreg laminate.
In this specification, the temperature Tc of the prepreg laminate at the time of cooling press means the temperature reached by the prepreg laminate when the prepreg laminate is cold-pressed, that is, the temperature of the prepreg laminate immediately after the cooling press. The temperature Tc of the prepreg laminate at the time of cooling press is measured by inserting a temperature sensor such as a thermocouple near the center in the thickness direction of the prepreg laminate.

The method for producing a fiber reinforced plastic according to the present invention is a method for producing a fiber reinforced plastic by heating a prepreg laminate in which two or more prepreg base materials in which a reinforced fiber is impregnated with a thermoplastic resin are laminated and then heating and cooling. is there.
In the method for producing a fiber-reinforced plastic of the present invention, the temperature Th (° C.) of the prepreg laminate at the time of heating and the temperature Tc (° C.) of the prepreg laminate at the time of the cooling press are the following conditions (1) to (3 ) To satisfy the above).
(1) Tm + 10 ≦ Th ≦ Tm + 100
(2) Tm-100 ≦ Tc ≦ Tm-10
(3) 20 ≦ Th−Tc ≦ 110
(However, Tm (° C.) represents the melting point of the thermoplastic resin, or the glass transition temperature when it does not have a melting point.)

Hereinafter, an example of the manufacturing method of the fiber reinforced plastic of this invention is demonstrated.
The manufacturing method of the fiber reinforced plastic of this embodiment has the following heating process and cooling press process.
Heating step: A prepreg laminate in which two or more prepreg base materials in which reinforcing fibers are impregnated with a thermoplastic resin is laminated is heated so as to satisfy the condition (1).
Cooling press step: The prepreg laminate after the heating step is cold-pressed so as to satisfy the conditions (2) and (3) to obtain a fiber reinforced plastic.

<Heating process>
In the heating step, the prepreg laminate is heated so that the temperature Th (° C.) of the prepreg laminate during heating satisfies Tm + 10 ≦ Th ≦ Tm + 100.
By setting the temperature Th to Tm + 10 (° C.) or higher, the thermoplastic resin can be sufficiently melted, and the respective prepreg base materials can be sufficiently integrated. Moreover, by making temperature Th below Tm + 100 (degreeC), deterioration of a thermoplastic resin can be suppressed and it can suppress that a thermoplastic resin leaks out from a prepreg laminated body.
The lower limit of the temperature Th is preferably Tm + 15 (° C.), and more preferably Tm + 20 (° C.). Further, the upper limit of the temperature Th is preferably Tm + 95 (° C.), and more preferably Tm + 90 (° C.).

  The heating time is preferably from 0.1 to 30 minutes, more preferably from 0.5 to 10 minutes.

When heating the prepreg laminate, it is preferable to press the prepreg laminate. That is, in the heating step, it is preferable to perform hot pressing so as to satisfy the condition (1) on the prepreg laminate. Thereby, integration of each prepreg base material in the prepreg laminate can be further promoted.
The pressure applied to the prepreg laminate during heating is preferably 0 to 10 MPa, more preferably 0.2 to 2 MPa. The pressure means a value obtained by dividing the pressing force applied to the prepreg laminate by the area of the prepreg laminate.

The heating device for heating the prepreg laminate is not particularly limited, and examples thereof include an electric heater heating device, a far infrared heater heating device, a near infrared heater heating device, and a press machine having a heating mechanism.
What is necessary is just to set suitably so that the setting temperature of a heating apparatus may satisfy | fill conditions (1) according to the kind of thermoplastic resin, and 100-400 degreeC is preferable.

[Prepreg laminate]
The prepreg laminate is obtained by laminating two or more prepreg base materials in which a reinforcing fiber is impregnated with a thermoplastic resin.
Since a thermoplastic resin generally has a higher toughness value than a thermosetting resin, it is easy to obtain a structural material excellent in strength, particularly impact resistance, by using the prepreg base material. Further, since the shape of the thermoplastic resin is determined by cooling and solidification without causing a chemical reaction, when the prepreg base material is used, molding can be performed in a short time, and the productivity is excellent.

(Prepreg base material)
As the prepreg base material, for example, a prepreg base material in which a reinforcing fiber aligned in one direction is impregnated with a thermoplastic resin can be used. By using the prepreg base material, the mechanical properties of the fiber-reinforced plastic obtained can be enhanced. In addition, a prepreg base material with a cut formed in a prepreg base material in which a reinforcing fiber is impregnated with a thermoplastic resin can also be used. By using the notched prepreg base material, the fluidity at the time of molding of the obtained fiber reinforced plastic can be improved, and a molded product having a complicated shape can be obtained more easily.

The reinforcing fiber is not particularly limited, and for example, a reinforcing fiber having an inorganic fiber, an organic fiber, a metal fiber, or a hybrid structure in which these are combined can be used.
Examples of the inorganic fiber include carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, and glass fiber. Examples of the organic fibers include aramid fibers, high density polyethylene fibers, other general nylon fibers, and polyester fibers. Examples of metal fibers include fibers such as stainless steel and iron, and carbon fibers coated with metal may be used. Of these, carbon fibers are preferred in view of mechanical properties such as the strength of the structural material that is the final molded product.
1-50 micrometers is preferable and, as for the average fiber diameter of a reinforced fiber, 5-20 micrometers is more preferable.
One type of reinforcing fiber may be used alone, or two or more types may be used in combination.

  Further, the number of reinforcing fibers in the fiber bundle composed of reinforcing fibers arranged in one direction is not particularly limited, and may be 20,000 or more large tow, and less than 20,000 regular tow. Also good.

The thermoplastic resin is not particularly limited, and polyamide resin (nylon 6 (melting point: 220 ° C.), nylon 66 (melting point: 260 ° C.), nylon 12 (melting point: 175 ° C.), nylon MXD6 (melting point: 237 ° C.), etc. ), Polyolefin resin (low density polyethylene (melting point: 95 to 130 ° C.), high density polyethylene (melting point: 120 to 140 ° C.), polypropylene (melting point: 168 ° C.), etc.), modified polyolefin resin (modified polypropylene resin (melting point: 160). ˜165 ° C.), etc.), polyester resin (polyethylene terephthalate, polybutylene terephthalate, etc.), polycarbonate resin (glass transition temperature: 145 ° C.), polyamideimide resin, polyphenylene oxide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin Polyetherimide resin, polystyrene resin, ABS resin, polyphenylene sulfide resin, liquid crystal polyester resin, a copolymer of acrylonitrile and styrene, a copolymer of nylon 6 and nylon 66 and the like.
Examples of the modified polyolefin resin include a resin obtained by modifying a polyolefin resin with an acid such as maleic acid.
A thermoplastic resin may be used individually by 1 type, and may use 2 or more types together.

  The thermoplastic resin contains at least one selected from the group consisting of polyolefin resins, modified polypropylene resins, polyamide resins and polycarbonate resins from the viewpoints of moldability, mechanical properties, impregnation into reinforcing fibers, and adhesiveness. Is preferred.

  For prepreg base materials, flame retardants, weather resistance improvers, antioxidants, heat stabilizers, UV absorbers, plasticizers, lubricants, colorants, compatibilizers, conductive materials, depending on the required properties of the target structural material You may mix | blend additives, such as a property filler.

When using the prepreg base material with a cut, a cut having a depth for cutting the reinforcing fiber is formed so as to intersect the fiber axis of the reinforcing fiber.
In general, the longer the reinforcing fiber, the more structural material excellent in mechanical properties can be obtained. However, the fluidity is lowered particularly during stamping molding, so that it becomes difficult to obtain a structural material having a complicated three-dimensional shape. In the prepreg base material with cuts, reinforcing fibers having a long fiber length aligned in one direction are in a state of being cut by the cuts. Thereby, since the reinforcing fiber is shortened, the reinforcing fiber and the thermoplastic resin easily flow even during stamping molding. Therefore, it is easy to obtain a complicated three-dimensional structural material such as a rib or a boss.
In addition, when sheet-like fiber reinforced plastic is formed by dispersing and integrating prepreg pieces, which are generally called random materials, cut out from a prepreg base material, mechanical properties vary, making it difficult to design parts. On the other hand, if the prepreg base material with cuts is used, the mechanical properties are better than those in the case of using a random material, and the variation can be reduced.

  5-100 mm is preferable and, as for the length L of the reinforced fiber cut | disconnected by the incision in a prepreg base material, 10-50 mm is more preferable. If the length L of the reinforcing fiber is not less than the lower limit, a fiber-reinforced plastic having sufficient mechanical properties can be easily obtained. If the length L of the reinforcing fiber is equal to or less than the upper limit value, the reinforcing fiber and the thermoplastic resin easily flow at the time of molding. Therefore, the obtained fiber-reinforced plastic is made into a structural material having a complicated three-dimensional shape such as a rib. It becomes easy to shape.

In the prepreg base material with cuts, the total length la of cuts per 1 m ² is preferably 10 m or more, and more preferably 20 m or more. When the total sum la is equal to or greater than the lower limit value, the fluidity becomes better and stamping molding into a complicated shape such as a rib becomes easy.
The total la is preferably 200 m or less, and more preferably 150 m or less. If the total sum la is not more than the upper limit value, a fiber-reinforced plastic having excellent mechanical properties can be easily obtained. In addition, since it is easy to make a cut, it is easy to prevent the prepreg base material from being cracked or missing reinforcing fibers and thermoplastic resin between adjacent cuts, which is advantageous in terms of manufacturing cost. is there.

The shape of the cut formed in the prepreg base material is not particularly limited, and may be, for example, linear, curved, or polygonal. By making the shape of the cut into a curved line, it becomes easier to increase the total sum la than in the case of a straight line.
Also, when making the incision into a curve,
A so-called wavy line that is a curve along a straight center line and does not overlap when the curve is projected onto the center line is preferable.

  The angle θ of the cut formed in the prepreg base material with respect to the fiber axis of the reinforcing fiber is not particularly limited. The larger the angle θ, the smaller the shear force between the fibers, so that the fluidity becomes higher and the stamping molding of complicated shapes such as ribs becomes easier. The smaller the angle θ, the easier it is to obtain a fiber reinforced plastic with higher mechanical properties.

The fiber volume content (Vf) in the prepreg substrate is preferably 20 to 55%. When Vf is equal to or greater than the lower limit, a structural material having sufficient mechanical properties is easily obtained. If Vf is not more than the upper limit value, good fluidity can be easily obtained at the time of shaping.
The Vf value means a value measured based on JIS K7075.

As for the thickness of a prepreg base material, 50-200 micrometers is preferable. If the thickness of a prepreg base material is more than a lower limit, since handling of a prepreg base material will become easy and it can suppress that the number of lamination | stacking of a prepreg base material increases too much, productivity will increase. If the thickness of a prepreg base material is below an upper limit, the impregnation property of a reinforced fiber and a thermoplastic resin will become favorable.
In this invention, the influence which the thickness of a prepreg base material has on the intensity | strength of the structural material finally obtained is small.

The manufacturing method of a prepreg base material is not specifically limited, A well-known method is employable. As the prepreg substrate, a commercially available prepreg substrate may be used.
Examples of the method for producing a prepreg base material include a method of impregnating a thermoplastic resin by sandwiching a reinforcing fiber sheet in which reinforcing fibers are arranged in a sheet shape between two thermoplastic resin films and performing heating and pressing. It is done. Only one type of thermoplastic resin film may be used, or two or more types may be used.

As a method for heating and pressurizing a prepreg base material, a known method can be adopted, and there are multi-step processes such as a method using two or more heat rolls, a method of combining a plurality of preheating devices and heat rolls, etc. It may be.
What is necessary is just to set heating temperature according to the kind of thermoplastic resin, and 100-400 degreeC is preferable. Further, the pressure during pressurization is preferably 0.1 to 10 MPa. When the heating temperature and pressure are within the above ranges, it becomes easy to impregnate the thermoplastic fibers between the reinforcing fibers.

  Examples of the method for forming the cut into the prepreg base material include a method using a laser marker, a cutting plotter, a die cutting, and the like. The method using a laser marker is preferable in that it can be processed at a high speed even when cutting a complicated shape such as a curved line or a zigzag line. The method using a cutting plotter is preferable in that processing is easy even with a large prepreg base material of 2 m or more. The method using a punching die is preferable because it can be processed at high speed.

(Mode of lamination)
The lamination | stacking aspect of the prepreg base material in a prepreg laminated body is not specifically limited. In the prepreg laminate, there are two types that differ in the type of reinforcing fiber, the type of thermoplastic resin, the presence or absence of cut, the length L of the reinforcing fiber, the sum la, the angle θ between the cut and the axial direction of the reinforcing fiber, etc. The above prepreg base materials may be laminated.
In the prepreg laminate, it is preferable to laminate the prepreg base material so that the angle θ is large and the total sum la is large in a thin portion such as a boss or rib that forms a three-dimensional shape during stamping molding. Further, in the prepreg laminate, the prepreg base material may be laminated so that the angle θ is small and the total la is small in a portion where the flow is two-dimensional and the flow length is small and high mechanical properties are required. preferable.

In addition, the prepreg laminate has a structure in which a plurality of prepreg base materials are laminated so that the directions of the reinforcing fibers are quasi-isotropic, reducing the anisotropy of the flow during pressing, and the strength of the fiber-reinforced plastic. This is preferable in terms of reducing the anisotropy. In the prepreg laminate, those in which the directions of the fiber axes of the reinforcing fibers between the prepreg base materials are different from those in which the fiber axes are aligned may be mixed.
For example, the prepreg laminated body by which the prepreg base material whose direction of a reinforced fiber is 0 degree and the prepreg base material which is 90 degrees was laminated | stacked alternately is mentioned. Further, it may be a prepreg laminate in which a plurality of prepreg base materials are laminated in the order of fiber axis directions of 0 °, 45 °, 90 °, and −45 ° (counterclockwise is positive).
In the prepreg base material laminated | stacked in a prepreg laminated body, it is preferable at the point which makes handling easy that prepreg base materials are adhere | attached by spot welding.

  4-96 are preferable and, as for the number of lamination | stacking of the prepreg base material in a prepreg laminated body, 8-48 are more preferable. If the number of laminated prepreg base materials is equal to or greater than the lower limit, a fiber-reinforced plastic having sufficient mechanical properties can be easily obtained. If the number of laminated prepreg base materials is equal to or less than the upper limit, the laminating work becomes easy and the productivity is excellent.

In the prepreg laminate, it is preferable to laminate a layer made of a thermoplastic resin between the prepreg base materials in terms of improving fluidity during pressing.
As a thermoplastic resin which forms a thermoplastic resin layer, the thermoplastic resin quoted by the prepreg base material is mentioned, for example. The thermoplastic resin in the prepreg base material and the thermoplastic resin in the thermoplastic resin layer may be the same or different.

<Cooling press process>
In the cooling press step, the prepreg laminate after the heating step is cold-pressed so as to satisfy the conditions (2) and (3) to obtain a fiber reinforced plastic. That is, the prepreg laminate after the heating step is cold-pressed so as to satisfy Tm-100 ≦ Tc ≦ Tm-10 and 20 ≦ Th-Tc ≦ 110 to obtain a fiber reinforced plastic.
The thermoplastic resin is solidified by the cooling press, and a fiber reinforced plastic in which each prepreg base material is integrated is obtained.

By setting the temperature Tc to Tm-10 (° C.) or lower, the thermoplastic resin can be sufficiently solidified, and the prepreg base materials can be sufficiently integrated. By setting Tc to Tm-100 (° C.) or more, the appearance of the resulting reinforced fiber plastic is improved.
The lower limit value of the temperature Tc is preferably Tm-95 (° C), more preferably Tm-90 (° C). Moreover, Tm-15 (degreeC) is preferable and, as for the upper limit of temperature Tc, Tm-20 (degreeC) is more preferable.

  In addition, by setting Th-Tc to 20 ° C. or higher, the thermoplastic resin can be sufficiently melted during heating and the thermoplastic resin can be sufficiently solidified during cooling press. The substrate can be sufficiently integrated. By setting Th-Tc to 110 ° C. or lower, warpage of the obtained fiber-reinforced plastic can be suppressed.

0.1-10 MPa is preferable and, as for the pressure applied to a prepreg laminated body at the time of cooling, 0.2-2 MPa is more preferable. The pressure means a value obtained by dividing the pressing force applied to the prepreg laminate by the area of the prepreg laminate.
The cooling press time is preferably from 0.1 to 30 minutes, more preferably from 0.5 to 10 minutes.

The cooling press device is not particularly limited, and examples thereof include a press machine having equipment for circulating a refrigerant and a heat medium, and a press machine having an electric heater.
What is necessary is just to set the preset temperature of a cooling press apparatus suitably so that conditions (2) and conditions (3) may be satisfied according to the kind of thermoplastic resin, and 80-160 degreeC is preferable.

  In the manufacturing method of the reinforced fiber plastic of the present invention, it is preferable to perform heating and cooling press in the state as it is without arranging anything on both sides of the prepreg laminate. Specifically, it is preferable that the prepreg laminate is directly installed in a heating device and heated, and further moved to a cooling press device as it is for cooling press. Thereby, the time required for the heating and cooling press can be shortened, which is advantageous in terms of productivity.

In the method for producing a reinforced fiber plastic according to the present invention, the lower surface of the prepreg laminate, or both the lower surface and the upper surface are superior in that the prepreg laminate is easy to handle and it is easy to move the prepreg laminate. It is preferable to arrange a metal plate or a resin sheet and perform the heating and cooling press.
Specifically, for example, as shown in FIG. 1, there is a method in which a metal plate 20 is disposed on both the lower surface and the upper surface of the prepreg laminate 10 and heating and cooling presses are performed.

Examples of the metal plate include an iron plate, an aluminum plate, and a stainless steel plate.
The thickness of a metal plate is not specifically limited, 0.1-5 mm is preferable.
Examples of the resin sheet include glass cloth impregnated with a resin. As resin used for a resin sheet, a fluororesin etc. are mentioned, for example.
The thickness of the resin sheet is not particularly limited, and is preferably 0.1 to 5 mm.

  Moreover, in the manufacturing method of the reinforced fiber plastic of this invention, you may perform a heating and cooling press using a heating apparatus or a cooling press machine in the state which pinched | interposed the prepreg laminated body with a pair of metal mold | die.

<Specific Embodiment>
Hereinafter, as an example of a specific embodiment of heating and cooling press of the prepreg laminate in the method for producing a fiber reinforced plastic of the present invention, a method (X) in which the prepreg laminate is not pressurized during heating, and a method in which pressure is applied ( Y) will be described.

In the method (X), as shown in FIG. 2, the prepreg laminate 10 is heated so as to satisfy the condition (1) by the heating device 100 including the heating portion 112 that heats the prepreg laminate 10 without applying pressure. .
Next, the prepreg laminate 10 is moved from the heating device 100 to the cooling press machine 130 by the transfer device 120.
Next, the upper press body 136 provided with the upper cooling part 134 that cools in contact with the upper surface of the upper body part 132 and the prepreg laminate 10, the lower body part 138, and the lower surface of the prepreg laminate 10 is cooled in contact with it. The prepreg laminate 10 is cooled and pressed so as to satisfy the condition (2) and the condition (3) by a cooling press machine 130 having a lower pressing body 142 having a lower cooling section 140 for performing fiber reinforced plastic. Get.

In the method (Y), as shown in FIG. 3, as shown in FIG. 3, an upper press body 156 including an upper body portion 152 and an upper heating portion 154 that heats the upper surface of the prepreg laminate 10, a lower body portion 158, While heating the prepreg laminate 10 so as to satisfy the condition (1), a heating press machine 150 having a lower press body 162 provided with a lower heating section 160 that is in contact with the lower surface of the prepreg laminate 10 and heats it. Pressurize.
Next, the prepreg laminate 10 is moved from the hot press machine 150 to the cooling press machine 130 by the transfer device 120.
Next, the upper press body 136 provided with the upper cooling part 134 that cools in contact with the upper surface of the upper body part 132 and the prepreg laminate 10, the lower body part 138, and the lower surface of the prepreg laminate 10 is cooled in contact with it. The prepreg laminate 10 is cooled and pressed so as to satisfy the condition (2) and the condition (3) by a cooling press machine 130 having a lower pressing body 142 having a lower cooling section 140 for performing fiber reinforced plastic. Get.

<Effect>
In the method for producing a fiber reinforced plastic according to the present invention, when the prepreg laminate is heated and cooled, the temperature of the prepreg laminate is controlled so as to satisfy the conditions (1) to (3). It is possible to suppress the occurrence of defects such as poor appearance, fiber meandering, resin leakage, and warping in the reinforced plastic.

  In addition, the manufacturing method of the fiber reinforced plastic of this invention is not limited to an above described method. For example, a method using an apparatus capable of continuously heating and cooling the prepreg laminate so as to satisfy the conditions (1) to (3) may be used.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
[Evaluation method]
The fiber reinforced plastic (plate-like material) obtained in each example was evaluated according to the following evaluation criteria.
(Integrated evaluation)
◯: The prepreg does not peel even when the obtained plate-like product is bent lightly.
X: When the obtained plate-like material is lightly bent, peeling of the prepreg occurs.
(Evaluation of solidification)
○: The obtained plate-like product is not sticky.
X: The obtained plate-like product is sticky.
(Resin leakage evaluation)
○: There is no protrusion of the resin on the end face of the obtained plate-like product.
X: There is protrusion of resin on the end face of the obtained plate-like product.
(Appearance evaluation)
○: The surface is smooth, there are no bumps, and there is gloss.
X: The surface is not smooth, bumpy and glossy.
(Fiber meandering evaluation)
○: The reinforcing fiber on the surface of the obtained plate-like product maintains linearity.
X: The reinforcing fibers on the surface are wavy in the obtained plate-like product.
(Warp evaluation)
○: There is no gap between the plate-like object and the surface plate on the obtained plate-like material on a smooth surface plate.
X: The obtained plate-like product has a gap between the plate-like product and the platen on a smooth platen.

[Example 1]
A continuous reinforcing fiber sheet having a basis weight of 72.0 g / m ² obtained by aligning carbon fibers (product name: Pyrofil TR-50S15L, manufactured by Mitsubishi Rayon, Inc.) in a flat shape so that the direction of the reinforcing fibers is one direction; did. The reinforcing fiber sheet is sandwiched from both sides with two acid-modified polypropylene resin films (acid-modified polypropylene resin: manufactured by Mitsubishi Chemical Corporation, product name: Modic P958, melting point 165 ° C., basis weight: 36.4 g / m ² ). Through a calender roll, a reinforced fiber sheet was impregnated with a thermoplastic resin to obtain a continuous prepreg having a fiber volume content (Vf) of 33%, a thickness of 0.12 mm, a width of 50 cm, and a length of 500 m.
From the obtained continuous prepreg, 16 layers of 50 cm × 50 cm prepreg base materials were cut out. Eight prepreg base materials whose fiber directions are 0 ° / 45 ° / 90 ° / −45 ° / −45 ° / 90 ° / 45 ° / 0 ° / 0 ° / 45 ° / 90 ° / −45 from the top. Lamination is performed in the order of ° / -45 ° / 90 ° / 45 ° / 0 °, spot welding is performed with an ultrasonic welding machine (product name: 2000LPt, manufactured by Nippon Emerson Co., Ltd.), and the laminated structure is symmetrical in the thickness direction. Thus, a 16-layer prepreg laminate in which the reinforcing fiber direction was pseudo-isotropic ([0 ° / 45 ° / 90 ° / −45 °] s2) was obtained.
The obtained prepreg laminate was heated alone for 4 minutes by an infrared heating apparatus (manufactured by NGK) set at 205 ° C. When the temperature Th of the prepreg laminate was measured, it reached 185 ° C. The prepreg laminate was moved to a press set at 90 ° C. (manufactured by Shinfuji Metal Industry) and cooled for 1 minute while being pressurized at 0.5 MPa. When the temperature Tc of the prepreg laminated body at the time of cooling press was measured, it reached 110 ° C. After the cooling press, the fiber reinforced plastic was taken out from the press.

[Examples 2 to 16]
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the production conditions were changed as shown in Tables 1 and 2.
In addition, when heat-pressing the prepreg laminate, a press machine (manufactured by Shinto Metal Industry) was used.

[Comparative Examples 1 to 20]
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the production conditions were changed as shown in Tables 2 and 3.
Note that “IR device” in Tables 1 to 3 means an infrared heating device (manufactured by NGK) (hereinafter the same).

As shown in Tables 1 to 3, in Examples 1 to 16 produced by the production method of the present invention, there were problems of poor prepreg integration, poor solidification of thermoplastic resin, resin leakage, poor appearance, fiber meandering, and warping. None of them occurred, and a fiber-reinforced plastic with good quality was obtained.
On the other hand, in Comparative Examples 1 to 20 manufactured by a method that does not satisfy the conditions (1) to (3), any of prepreg integration failure, thermoplastic resin solidification failure, resin leakage, appearance failure, fiber meandering, warping One or more problems were seen, and good quality fiber reinforced plastics could not be obtained.

[Examples 17 to 22]
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that aluminum plates having a thickness of 3 mm were respectively arranged on both sides of the 16-layer prepreg laminate, and the production conditions were changed as shown in Table 4.

[Comparative Examples 21 to 26]
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that aluminum plates having a thickness of 3 mm were respectively arranged on both sides of the 16-layer prepreg laminate, and the production conditions were changed as shown in Table 4.

As shown in Table 4, in Examples 17 to 22 where aluminum plates were arranged on both sides of the prepreg laminate and manufactured by the manufacturing method of the present invention, poor prepreg integration, poor thermoplastic resin solidification, resin leakage There were no problems in appearance, fiber meandering, or warping, and a fiber-reinforced plastic with good quality was obtained.
On the other hand, in Comparative Examples 21 to 26 manufactured by a method not satisfying the conditions (1) to (3), any of prepreg integration failure, thermoplastic resin solidification failure, resin leakage, appearance failure, fiber meandering, warping One or more problems were seen, and good quality fiber reinforced plastics could not be obtained.

[Examples 23 to 28]
Except that a fluororesin-containing glass cloth (manufactured by Nitto Denko) having a thickness of 0.34 mm was disposed on both sides of the 16-layer prepreg laminate, and the production conditions were changed as shown in Table 5, the same as in Example 1. To obtain fiber reinforced plastic.

[Comparative Examples 27-32]
Except that a fluororesin-containing glass cloth (manufactured by Nitto Denko) having a thickness of 0.34 mm was disposed on both sides of the 16-layer prepreg laminate, and the production conditions were changed as shown in Table 5, the same as in Example 1. To obtain fiber reinforced plastic.

As shown in Table 5, in Examples 23 to 28 in which the fluororesin-containing glass cloth was arranged on both sides of the prepreg laminate and manufactured by the manufacturing method of the present invention, the prepreg was poorly integrated and the thermoplastic resin was not solidified. There were no problems of resin leakage, poor appearance, fiber meandering, or warping, and a fiber-reinforced plastic with good quality was obtained.
On the other hand, in Comparative Examples 27 to 32 manufactured by a method not satisfying the conditions (1) to (3), any of prepreg integration failure, thermoplastic resin solidification failure, resin leakage, appearance failure, fiber meandering, or warping One or more problems were seen, and good quality fiber reinforced plastics could not be obtained.

[Example 29]
Except for using a polyamide 6 resin (Mitsubishi Resin, melting point 225 ° C.) instead of an acid-modified polypropylene resin as a thermoplastic resin, and using a notched prepreg base material with a notch, the same as in Example 1. A fiber reinforced plastic was obtained.
The cut prepreg base material had a Vf of 38% and a thickness of about 0.1 mm. When cutting into the prepreg base material, the cutting fiber having a punching blade embedded in a roll is used to continuously cut into a region inside 5 mm from the edge of the prepreg base material, and the reinforced fiber is divided. length L is 25.0 mm, an average cut length l is 20.0 mm, the cut and the angle θ of 30 ° of the reinforcing fibers, the switching so that the sum la the cutting length per 1 m ² is 80.0m It was embedding.

[Examples 30 to 36]
A fiber reinforced plastic was obtained in the same manner as in Example 29 except that the production conditions were changed as shown in Table 6.

[Comparative Examples 33 to 42]
A fiber reinforced plastic was obtained in the same manner as in Example 29 except that the production conditions were changed as shown in Tables 6 and 7.

As shown in Tables 6 and 7, in Examples 29 to 36 manufactured by the manufacturing method of the present invention, problems of poor prepreg integration, poor solidification of thermoplastic resin, resin leakage, poor appearance, fiber meandering, and warping. Neither occurred, and a fiber-reinforced plastic with good quality was obtained.
On the other hand, in Comparative Examples 33 to 42 manufactured by a method that does not satisfy the conditions (1) to (3), any of prepreg integration failure, thermoplastic resin solidification failure, resin leakage, appearance failure, fiber meandering, warping One or more problems were seen, and good quality fiber reinforced plastics could not be obtained.

DESCRIPTION OF SYMBOLS 10 Prepreg laminated body 20 Metal plate 100 Heating device 120 Transfer device 130 Cooling press machine 150 Heating press machine

Claims (7)

A method of producing a fiber reinforced plastic by heating a prepreg laminate in which two or more prepreg base materials in which a reinforced fiber is impregnated with a thermoplastic resin are laminated, and then heating and cooling.
Fiber reinforcement that controls the temperature Th (° C.) of the prepreg laminate during heating and the temperature Tc (° C.) of the prepreg laminate during cooling press so as to satisfy the following conditions (1) to (3) Plastic manufacturing method.
(1) Tm + 10 ≦ Th ≦ Tm + 100
(2) Tm-100 ≦ Tc ≦ Tm-10
(3) 20 ≦ Th−Tc ≦ 110
(However, Tm (° C.) represents the melting point of the thermoplastic resin, or the glass transition temperature when it does not have a melting point.)   The manufacturing method of the fiber reinforced plastics of Claim 1 which arrange | positions a metal plate or a resin sheet to the lower surface of the said prepreg laminated body, or both a lower surface and an upper surface, and performs the said heating and cooling press.   The manufacturing method of the fiber reinforced plastics of Claim 1 which performs the said heating and cooling press in the state as it is, without arrange | positioning anything on both surfaces of the said prepreg laminated body.   The manufacturing method of the fiber reinforced plastics of Claim 1 which performs the said heating and cooling press in the state which pinched | interposed the said prepreg laminated body with a pair of metal mold | die.   The manufacturing method of the fiber reinforced plastics as described in any one of Claims 1-4 which presses the said prepreg laminated body when performing the said heating.   The manufacturing method of the fiber reinforced plastics as described in any one of Claims 1-5 by which the reinforced fiber in the said prepreg base material is aligned in one direction.   The manufacturing method of the fiber reinforced plastics as described in any one of Claims 1-6 in which the notch is formed in the reinforced fiber of the said prepreg base material.

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