JP6477114B2 - Fiber reinforced thermoplastic resin laminate and method for producing the same - Google Patents

Description

  The present invention relates to a fiber reinforced thermoplastic resin laminate, and more particularly to a fiber reinforced plastic laminate which is excellent in balance between moldability and mechanical properties and is inexpensive. More specifically, it is excellent in shaping into a complicated shape at the time of stamping molding, can be molded in a short time, maintains mechanical strength as a structural member, and is suitably used for aircraft members, automobile members, sports equipment, etc. The present invention relates to a fiber reinforced plastic laminate.

  Carbon fiber reinforced thermoplastics made of carbon fiber and thermoplastic resin are widely used in electrical / electronic applications, civil engineering / architecture applications, automotive applications, aircraft applications and the like because of their excellent specific strength and specific rigidity. As a method for molding fiber-reinforced thermoplastics, an intermediate base material impregnated with a thermoplastic resin is laminated on continuous reinforcing fibers called prepregs, and shaped into a desired shape by heating and pressing with a press or the like. Stamping is most commonly performed. The fiber reinforced plastic obtained in this way has excellent mechanical properties because it uses continuous reinforcing fibers. Further, by arranging the continuous reinforcing fibers regularly, it is possible to design the required mechanical properties, and the variation in the mechanical properties is small. However, since carbon fiber is expensive, there is a problem with respect to economy, and since it is a continuous reinforcing fiber, fluidity is low, so it is difficult to form a complicated shape such as a three-dimensional shape, mainly a planar shape. There is a demand for further improvement.

  In order to solve this problem, there is a method for obtaining a sheet having excellent fluidity and excellent stamping formability by dispersing a chip-like prepreg obtained by cutting a tape-like prepreg having a narrow width into a predetermined length on a flat surface. It is disclosed (for example, Document 1). However, it is extremely difficult to dispose a chip-shaped prepreg having a certain width and length on a flat plate in a completely random direction, and therefore, there is a problem that mechanical properties vary depending on the location and orientation even in the same sheet.

  In addition, by cutting into a prepreg made of continuous fiber and thermoplastic resin, it can be molded in a short time, exhibits excellent formability during molding, and exhibits excellent mechanical properties when used as a fiber reinforced plastic. Then, a base material is disclosed (for example, Documents 2 and 3). However, compared with LFT-D, the mechanical properties are high and the variation is small, but the strength is not sufficient for application as a structural material.

  In addition, a method for improving the above-described strength and its variation by optimizing the cutting shape is disclosed (for example, Documents 4, 5, and 6). However, according to this method, improvement in mechanical properties and variation can be seen, but since the amount of expensive carbon fiber is large, the economical problem has not been solved. In addition, since the stamping formability is insufficient, there is a problem with the formability to three-dimensional shapes such as ribs and bosses. As a countermeasure, the sheet heating time is increased in the preheating process during stamping molding. However, in this case, there is a problem that the prepreg is likely to be thermally decomposed to generate decomposition gas, and the mechanical properties and appearance of the molded product are deteriorated.

  A number of sandwich laminate structures in which fiber reinforced composite materials (skins) are laminated on both sides of an inexpensive resin (core) have been described (for example, Reference 7) in order to fill the drawbacks of the above materials. Although lightness can be improved while ensuring mechanical properties, there is a problem with the moldability of complicated shapes such as three-dimensional shapes, and it is necessary to increase the pressure in the pressurization process during stamping molding. Since the core and the skin are easily separated, the fiber distribution is uneven, and there is a problem that the mechanical properties differ depending on the location and orientation of the molded product.

JP 07-164439 A Japanese Unexamined Patent Publication No. 63-247010 JP-A 63-267523 JP 2008-207544 A JP 2008-207545 A JP 2009-286817 A WO2006 / 028107

  The present invention seeks to solve the problems associated with the prior art as described above, and has excellent mechanical properties applicable to structural materials, while having small variations in mechanical properties and more complicated shapes. It is to provide a fiber-reinforced plastic laminate that can be molded in a short time and is inexpensive.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has at least a three-layer structure (A) layer having excellent mechanical properties in both surface layers, and excellent stamping moldability in the intermediate layer. It was found that a carbon fiber reinforced plastic laminate having an excellent balance between moldability and mechanical properties and being inexpensive can be obtained by using a laminate in which the (B) layer having the above structure is used. That is, the gist of the present invention resides in the following [1] to [12].

  [1] A fiber reinforced thermoplastic resin laminate having at least a three-layer structure, the following (A) layer on both surface layers, and the following (B) layer between both surface layers.

  (A) Layer: A laminate composed of a prepreg in which a reinforced fiber oriented in one direction is impregnated with a thermoplastic resin, and the prepreg has a depth of cut to cut the reinforced fiber in a direction crossing the reinforced fiber. (A) The prepregs constituting the layer (A) are laminated such that the directions of the reinforcing fibers contained in the prepreg are pseudo-isotropic, or the prepregs at 0 degrees and the prepregs at 90 degrees are alternately arranged. Are stacked.

  (B) Layer: A sheet made of a thermoplastic resin composition and / or a sheet made of a filler-containing thermoplastic resin composition, and the melting point TmB of the thermoplastic resin is the heat constituting the prepreg of the layer (A). It is the melting point TmA or more of the plastic resin.

[2] The laminate obtained by laminating the (A) layer and the (B) layer is heated to the melting point TmA + 50 ° C. or higher of the thermoplastic resin of the (A) layer, and the heated laminate is calculated by the following (formula 1). In a molded product produced by placing a laminate at a charge rate of 40 to 100% and then pressing, the reinforcing fiber filling rate (Vf1) in the charge part is divided by the reinforcing fiber filling rate (Vf2) in the fluid part. The fiber reinforced thermoplastic resin laminate according to the above [1], wherein the measured value is 1.5 or less.
Charge rate (%) = laminate body area (mm ² ) / surface area of mold cavity (mm ² ) × 100 (Formula 1)

[3] In the above [1] or [2], the melting point TmB of the thermoplastic resin used in the layer (B) and the melting point TmA of the thermoplastic resin used in the layer (A) satisfy the following (formula 2). The fiber-reinforced thermoplastic resin laminate described.
TmB−TmA ≧ 30 (Formula 2)

  [4] The fiber reinforcement according to any one of [1] to [3], wherein a value obtained by dividing the total thickness of the (A) layer by the total thickness of the (B) layer is 0.1 or more and 3 or less. Thermoplastic resin laminate.

  [5] The thickness of each surface layer is 0.1 mm or more and 1.5 mm or less, and the sum of the thicknesses of (A) layers is 2.5 mm or less, in any one of [1] to [4] above The fiber-reinforced thermoplastic resin laminate described.

[6] (A) The cuts of the prepreg constituting the layer are linear, the angle between the cut and the carbon fiber is 30 ° or more and 60 ° or less, and the total cut length per 1 m ^{2 of} the prepreg is 20 m. The fiber-reinforced thermoplastic resin laminate according to any one of [1] to [5] above, which is 250 m or shorter.

  [7] The fiber reinforced thermoplastic resin laminate according to the above [6], wherein the average fiber length of the reinforcing fibers constituting the layer (A) is 10 mm or more and 50 mm or less.

  [8] The fiber-reinforced thermoplastic resin laminate according to any one of [1] to [7], wherein the volume content of the reinforcing fibers constituting the layer (A) is 20% to 60%.

  [9] The fiber-reinforced thermoplastic resin laminate according to any one of [1] to [8], wherein the reinforcing fibers constituting the layer (A) are carbon fibers.

  [10] The fiber reinforced heat according to any one of [1] to [9], wherein the single fiber fineness of the reinforcing fibers constituting the layer (A) is a carbon fiber of 0.5 dtex or more and 2.4 dtex or less. Plastic resin laminate.

  [11] The fiber reinforced heat according to any one of [1] to [10], wherein the number of filaments in the fiber bundle of the reinforcing fibers constituting the layer (A) is 3,000 or more and 100,000 or less. Plastic resin laminate.

  [12] By heating the (A) layer and the (B) layer above the softening point or melting point of the thermoplastic resin composition constituting the (A) layer and the thermoplastic resin composition constituting the (B) layer. The manufacturing method of the fiber reinforced thermoplastic resin laminated body in any one of said [1] to [11] to fuse | melt.

  According to the present invention, while having excellent mechanical properties applicable to structural materials, variation in mechanical properties is small, and furthermore, it is excellent in formability to complex shapes, so that it can be molded in a short time and is inexpensive. A carbon fiber reinforced plastic laminate can be obtained.

  Hereinafter, the manufacturing method and sheet of the fiber-reinforced thermoplastic resin laminate of the present invention will be described in detail.

  The fiber reinforced thermoplastic resin laminate of the present invention is a laminate having at least a three-layer structure, wherein the following (A) layer is used for both surface layers, and the following (B) layer is used between both surface layers: It is characterized by.

  (A) Layer: A laminate composed of a prepreg in which a reinforced fiber oriented in one direction is impregnated with a thermoplastic resin, and the prepreg has a depth of cut to cut the reinforced fiber in a direction crossing the reinforced fiber. (A) The prepregs constituting the layer (A) are laminated such that the directions of the reinforcing fibers contained in the prepreg are pseudo-isotropic, or the prepregs at 0 degrees and the prepregs at 90 degrees are alternately arranged. Are stacked.

  (B) Layer: A sheet made of a thermoplastic resin composition and / or a sheet made of a filler-containing thermoplastic resin composition, and the melting point TmB of the thermoplastic resin is the heat constituting the prepreg of the layer (A). It is the melting point TmA or more of the plastic resin.

Further, the laminate obtained by laminating the (A) layer and the (B) layer is heated to the melting point TmA + 50 ° C. or higher of the thermoplastic resin of the (A) layer, and the heated laminate is calculated by the following (formula 1). In a molded body produced by installing the laminate at a rate of 40 to 100% and then pressing, the filling rate (Vf1) of reinforcing fibers in the charge part was divided by the filling rate (Vf2) of reinforcing fibers in the fluid part The fiber reinforced thermoplastic resin laminate according to the above [1] having a value of 1.5 or less is preferred. In other words, it is preferable that the difference in the filling rate of the reinforcing fibers in the charge part and the fluid part is smaller in terms of material.
Charge rate (%) = laminate body area (mm ² ) / surface area of mold cavity (mm ² ) × 100 (Formula 1)

  In the present invention, the charge portion refers to a portion where the laminate was originally present, and the fluid portion refers to a portion that is newly formed by flowing part of the laminate due to heat and pressure.

((A) layer)
For the layer (A) that can be used in the laminate of the present invention, it is necessary to use a prepreg obtained by impregnating a thermoplastic resin into reinforcing fibers that are aligned in one direction and arranged in a plane. A prepreg laminate used for the layer (A) can be obtained by laminating two or more pieces obtained by cutting continuous fibers by cutting into the prepreg. The reinforcing fiber contained in the prepreg is preferably 20 to 60% by volume (volume oil content of reinforcing fiber: 20% to 60%), more preferably 30 to 50% by volume (volume oil content of reinforcing fiber: 30%). More than 50%). The thickness of the prepreg is not particularly limited, but is preferably 50 to 300 μm, and more preferably 100 to 200 μm, from the viewpoint of combining formability and strength improvement effect.

(Thermoplastic resin)
Examples of the thermoplastic resin that can be used in the prepreg that can be used in the present invention include polystyrene, (meth) acrylic acid ester / styrene copolymer, acrylonitrile / styrene copolymer, and styrene / maleic anhydride copolymer. Styrene resins such as ABS, ASA and AES; acrylic resins such as polymethyl methacrylate; polycarbonate resins; polyamide resins; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyphenylene ether resins; Resin; polysulfone resin; polyarylate resin; polyphenylene sulfide resin; thermoplastic polyurethane resin; polyethylene, polypropylene, polybutene, poly-4-methylpentene, ethylene / propylene Polymers, polyolefin resins such as ethylene / butene copolymers; ethylene / vinyl acetate copolymers, ethylene / (meth) acrylic acid ester copolymers, ethylene / maleic anhydride copolymers, ethylene / acrylic acid copolymers Copolymers of α-olefins such as polymers and various monomers; Aliphatic polyester resins such as polylactic acid, polycaprolactone, aliphatic glycol / aliphatic dicarboxylic acid copolymers; biodegradable cellulose, polypeptides And biodegradable resins such as polyvinyl alcohol, starch, carrageenan, and chitin / chitosan. From the viewpoint of strength and workability, a crystalline resin is preferable, and a polyamide-based resin is more preferable. Furthermore, if necessary, various resin additives can be blended. Examples of resin additives include colorants, antioxidants, metal deactivators, carbon black, nucleating agents, mold release agents, lubricants, Antistatic agents, light stabilizers, ultraviolet absorbers, impact modifiers, melt tension improvers, flame retardants and the like.

(Reinforced fiber)
As the reinforcing fiber constituting the layer (A) of the present invention (the reinforcing fiber that can be used for the prepreg constituting the layer (A)), the kind of the reinforcing fiber is not particularly limited, and inorganic fiber, organic fiber, metal fiber. Alternatively, a reinforcing fiber having a hybrid configuration 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 organic fibers include aramid fibers, high density polyethylene fibers, other general nylon fibers, and polyesters. Examples of the metal fibers include fibers such as stainless steel and iron, and may be carbon fibers coated with metal. Among these, carbon fibers are preferable in consideration of mechanical properties such as strength of the final molded product. Moreover, it is preferable that the average fiber diameter of a reinforced fiber is 1-50 micrometers, and it is more preferable that it is 5-20 micrometers.

((A) Carbon fiber constituting layer (carbon fiber constituting prepreg constituting (A) layer: hereinafter referred to as “carbon fiber”))
The various values of the following “carbon fiber” can be read as the value of the reinforcing fiber in the present invention.

  The carbon fiber is not particularly limited, and any carbon fiber such as polyacrylonitrile (PAN), petroleum / coal pitch, rayon, and lignin can be used. In particular, PAN-based carbon fibers using PAN as a raw material are preferable because they are excellent in productivity and mechanical properties on an industrial scale. These are available as commercial products.

  The total fineness of the carbon fiber bundle is preferably 200 to 7000 tex. The number of filaments may be 1,000 or more, preferably 3000 or more. Moreover, generally 100,000 or less is preferable, More preferably, it is 60000 or less. The strength of the carbon fiber bundle is preferably 1 to 10 GPa, more preferably 5 to 8 GPa. The elastic modulus is preferably 100 to 1,000 GPa, more preferably 200 to 600 GPa.

  In addition, the intensity | strength and elastic modulus of a carbon fiber bundle say the intensity | strength measured by the method of JIS-R7608, and an elastic modulus. The single fiber fineness (average single fiber fineness) in the present invention is not particularly limited, but is preferably 0.5 to 2.4 dtex.

  The carbon fiber that can be used in the laminate of the present invention and can be used in the prepreg is preferably subjected to surface treatment, particularly electrolytic treatment. Examples of the surface treatment agent include an epoxy sizing agent, a urethane sizing agent, a nylon sizing agent, and an olefin sizing agent. By performing the surface treatment, an advantage that tensile strength and bending strength are improved can be obtained. As a method for producing a prepreg, a method of impregnating a reinforcing fiber aligned in one direction with a thermoplastic resin such as a nonwoven fabric, a film, or a sheet and heating and pressurizing the resin can be used.

  The prepreg that can be used for the layer (A) of the present invention is prepared by, for example, preparing two sheets of thermoplastic resin in the form of a film, sandwiching a reinforcing fiber sheet in which reinforcing fibers are arranged in a sheet shape, and heating And by applying pressure. More specifically, two films are sent out from two rolls of a film made of thermoplastic resin, and a reinforcing fiber sheet supplied from a roll of reinforcing fiber sheets is placed between the two films. After sandwiching, heat and pressurize. As a means for heating and pressurizing, known means can be used, which requires a multi-step process such as using two or more heat rolls or using multiple pairs of preheating devices and heat rolls. It may be. Here, the thermoplastic resin constituting the film does not have to be one type, and a film made of another type of thermoplastic resin may be further laminated using the apparatus as described above.

  Although the said heating temperature is based also on the kind of thermoplastic resin, it is preferable that it is 100-400 degreeC normally. On the other hand, the pressure during pressurization is preferably 0.1 to 10 MPa. If it is this range, since it can be made to impregnate a thermoplastic resin between the reinforced fiber contained in a prepreg, it is preferable. Moreover, the prepreg which can be used for the laminated base material of this invention can also use the prepreg marketed.

The prepreg comprising the reinforcing fiber constituting the layer (A) and the thermoplastic resin composition used in the present invention has a depth of cut that cuts the reinforcing fiber in a direction crossing the reinforcing fiber. Is preferably 60 degrees or less, more preferably 30 degrees or more and 60 degrees or less, and the total cutting length 1a per prepreg 1 m ² is 20 m or more, usually 250 m or less, preferably Is preferably 150 m or less, more preferably 100 m or less, in terms of a good balance between moldability and mechanical properties of the carbon fiber reinforced plastic laminate.

The shape of the notch need not be linear. By using the curve, the total cutting length 1a per 1 m ² can be increased while maintaining the same cutting angle and the same fiber length. In this case, improvement in moldability can be expected while maintaining high mechanical properties.

  In the prepreg contained in the laminated base material of the present invention, the length L of the cut reinforcing fiber is not particularly limited, but is preferably 5 mm or more and 100 mm or less from the viewpoint of mechanical properties and fluidity. In particular, 10 mm or more and 50 mm or less is more preferable in order to achieve both sufficient mechanical properties and flow to a thin portion such as a rib during stamping molding.

  The prepreg that can be used in the present invention can be obtained by making a cut using a laser marker, a cutting plotter, a cutting die, or the like, and the cut is made using a laser marker. It is preferable because it has the effect of being able to process complex incisions such as curves and zigzag lines at high speed, and if the incisions are made using a cutting plotter, a large prepreg layer of 2 m or more is processed. Since there exists an effect that it can do, it is preferable. Furthermore, it is preferable that the cut is made by using a punching die because there is an effect that processing can be performed at high speed.

  The prepreg laminate including the reinforcing fiber and the thermoplastic resin composition used for the layer (A) of the present invention is a laminate in which a plurality of prepregs are laminated so that the directions of the reinforcing fibers are pseudo-isotropic. This is preferable in terms of reducing the anisotropy.

  In the prepreg laminate including the carbon fibers and the thermoplastic resin composition used in the layer (A) of the present invention, the prepregs in which the direction of the reinforcing fibers contained in the prepreg is 0 degrees and the prepregs that are 90 degrees are alternately laminated. It is preferable in terms of reducing the anisotropy of the laminate.

((B) layer)
As the thermoplastic resin constituting the (B) layer used in the present invention, one having a melting point higher than that of the thermoplastic resin used for the (A) layer is used. For example, polystyrene, (meth) acrylic ester / styrene copolymer, acrylonitrile / styrene copolymer, styrene / maleic anhydride copolymer, styrene resin such as ABS, ASA, AES; acrylic such as polymethyl methacrylate Polycarbonate resins; Polyamide resins; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polyphenylene ether resins; Polyoxymethylene resins; Polysulfone resins; Polyarylate resins; Polyphenylene sulfide resins; Plastic polyurethane resin; Polyolefin resin such as polyethylene, polypropylene, polybutene, poly-4-methylpentene, ethylene / propylene copolymer, ethylene / butene copolymer; ethylene / vinyl acetate Copolymers of α-olefin and various monomers such as ethylene copolymer, ethylene / (meth) acrylic acid ester copolymer, ethylene / maleic anhydride copolymer, ethylene / acrylic acid copolymer; Aliphatic polyester resins such as polylactic acid, polycaprolactone, aliphatic glycol / aliphatic dicarboxylic acid copolymer; biodegradable resins such as biodegradable cellulose, polypeptide, polyvinyl alcohol, starch, carrageenan, chitin / chitosan Is mentioned. Among them, a polyamide-based resin or a polycarbonate resin is preferable because it has a high melting point and excellent resistance to drawdown, so that it is easy to charge the laminate sheet to the mold after the preheating process at the time of stamping molding and is excellent in handling. .

  Furthermore, if necessary, various resin additives can be blended. Examples of resin additives include colorants, antioxidants, metal deactivators, carbon black, nucleating agents, mold release agents, lubricants, Antistatic agents, light stabilizers, ultraviolet absorbers, impact modifiers, melt tension improvers, flame retardants and the like.

  Furthermore, you may have a filler as needed, and specifically, various inorganic fillers can be mix | blended. The inorganic filler is not particularly limited, and examples thereof include fibrous fillers such as glass fibers and carbon fibers, plate fillers such as talc, mica, and graphite, and particulate fillers such as calcium carbonate and silica. A fibrous filler or a plate-like filler is preferable, and a fibrous filler (reinforced fiber) is more preferable. An anisotropic filler is easy to increase the strength in a specific direction. A plurality of these fillers may be used simultaneously.

  A commercially available product may be used as the thermoplastic resin of the layer (B) that can be used for the molded product of the present invention. For example, examples of the polyamide resin include DuPont 101F and Daicel Eponic C2000 (both are product names).

The melting point TmB of the thermoplastic resin of the (B) layer that can be used for the molded product of the present invention is not less than the melting point TmA of the thermoplastic resin used in the (A) layer, and preferably has a high melting point of 30 ° C. or higher. . That is, it is preferable to satisfy the following (Formula 2).
TmB−TmA ≧ 30 (Formula 2)

  When the temperature is lower than the thermoplastic resin no melting point TmA used in the (A) layer, the fiber distribution becomes large, and the strength and rigidity suitable for the structural material cannot be obtained.

  The value obtained by dividing the total thickness of the (A) layer used in the present invention by the total thickness of the (B) layer is from 0.1 to 3, more preferably from 0.3 to 2. If the above value is 3 or more, the fluidity is lowered, and if it is 3 or more, sufficient strength and rigidity cannot be obtained.

(Manufacturing method of fiber reinforced plastic laminate)
The fiber reinforced plastic laminate of the present invention is obtained by heating and heating a layer A of a prepreg laminate containing reinforced fibers oriented in one direction and a thermoplastic resin composition and a layer B of the thermoplastic resin composition at a softening point or higher than the melting point. The method of pressing and integrating is mentioned.

  Specifically, it can be carried out using a normal apparatus, for example, a heating press, and a mold having a desired shape can be used as the mold used at that time. As the material of the mold, those usually used in hot stamping molding can be adopted, and a so-called metal mold can be used. Specifically, this step can be performed, for example, by placing the laminate in a mold and heating and pressing.

  In the heating, although it depends on the type of thermoplastic resin contained in the laminate, it is preferably heated at 100 to 400 ° C, more preferably 150 to 350 ° C. Prior to the heating, preliminary heating may be performed. About preheating, it is preferable to heat at 150-400 degreeC normally, Preferably it is 200-380 degreeC.

  As a pressure applied to a laminated body in the said pressurization, Preferably it is 0.1-10 MPa, More preferably, it is 0.2-2 MPa. The pressure is a value obtained by dividing the pressing force by the area of the laminated base material.

  The heating and pressurizing time is preferably 0.1 to 30 minutes, more preferably 0.5 to 10 minutes. Moreover, it is preferable that the cooling time provided after a heating and pressurization is 0.5 to 30 minutes.

  The thickness of the integrated carbon fiber reinforced thermoplastic laminate according to the present invention that has undergone the hot stamping molding is preferably 0.5 to 10 mm.

  In addition, you may perform the said heating and pressurization on the conditions where a lubricant exists between a metal mold | die and the said laminated body. Due to the action of the lubricant, the fluidity of the carbon fibers contained in the prepreg constituting the laminated base material during the heating and pressurization is increased, so that the impregnation of the thermoplastic resin between the carbon fibers is increased and the resulting lamination is obtained. This is because voids between the carbon fibers and between the carbon fibers and the thermoplastic resin in the body can be reduced.

  As the lubricant, for example, a silicone-based lubricant or a fluorine-based lubricant can be used. Moreover, you may use these mixtures. As the silicone-based lubricant, a heat-resistant one that can be used in a high-temperature environment is preferably used. More specifically, silicone oils such as methylphenyl silicone oil and dimethyl silicone oil can be exemplified, and commercially available ones can be preferably used. As the fluorine-based lubricant, a heat-resistant one that can be used in a high temperature environment is preferably used. As specific examples of such a material, fluorine oil such as perfluoropolyether oil or a low polymer of ethylene trifluoride chloride (weight average molecular weight 500 to 1300) can be used.

  The lubricant is applied on one or both surfaces of the laminate, on one or both surfaces of the mold, or on one or both surfaces of both the laminate and the mold. It may be supplied by appropriate means, or may be applied in advance on the surface of the mold. Among these, a mode in which the lubricant is supplied to the surfaces on both sides of the laminate is preferable.

Following is a more detailed description of the present invention through examples, the present invention is not intended to be limited to the description of Example. Example 1 is a reference example.

(Stamping formability evaluation)
Using a far-infrared heater type heating device (NGK Kiln Tech Co., Ltd., product name: H7GS-71289) with a heater temperature set at 380 ° C., two laminate sheets having a thickness of 1.5 mm cut into 200 mm × 200 mm, Heat to soften for 4 to 5 minutes without overlapping each other.

  Using a 500 ton press machine (product name: FMP2-500, manufactured by Kawasaki Yoko Co., Ltd.) using a flat plate mold of 300 × 300 mm with a thickness of 1.5 mm, the two laminated sheets are stacked in a gold state. After charging the central part of the mold, press molding is performed under the conditions of a charge time of 25 s, a mold temperature of 150 ° C., a molding pressure of 10 MPa, and a molding time of 1 minute to obtain a molded product of 300 mm × 300 mm and a thickness of 1.5 mm.

  From the molded product, a sample is cut out at two places of the charge part and the fluid part, the density is measured, and the carbon fiber volume content Vf (%) is calculated.

  Further, from the molded product, a test piece was produced by cutting out at 0 ° with respect to the fiber orientation direction with a length of 100 mm and a width of 25 mm at the charge part and the fluid part. According to the test method specified in JIS K-7074, using a universal testing machine (Instron, product name: Model 4465), the distance between the gauge points is 80 mm, and the crosshead speed is 5.0 mm / min. A test is performed to calculate the bending strength and the flexural modulus. The number of test specimens measured is n = 3, and the average value is taken as the strength and elastic modulus. It should be noted that if the bending elastic modulus values at two locations are both 30 GPa or more, the fiber distribution is small and the rigidity is excellent. ○ If there is a bending elastic modulus of 30 GPa or less even at one location, the fiber distribution is large and the rigidity is high. X is assumed to be inferior.

(Prepreg production)
Carbon fiber (manufactured by Mitsubishi Rayon, product name: Pyrofil TR-50S15L) is made into a reinforcing fiber sheet having a basis weight of 72.0 g / m ² by aligning the reinforcing fibers in a plane so that the direction of the reinforcing fibers is one direction. Both sides of this reinforcing fiber sheet are sandwiched between nylon 6 films (Nylon 6: manufactured by Ube Industries, product name: 1013B, thickness: 40μ), and a calender roll is passed multiple times to impregnate the reinforcing fiber sheet with thermoplastic resin. Thus, a prepreg having a carbon fiber volume content (Vf) of 34% and a thickness of 0.125 mm is obtained.

Example 1
The obtained prepreg was cut into a 300 mm square and cut using a sample cutting machine (manufactured by Rezac, product name: L-2500) at regular intervals as shown in Table 1. At that time, except for the inner part of the sheet 5 mm from the end of the sheet, the length of the reinforcing fiber L = 25.0 mm is constant and the average cutting length l = 14.1 mm is formed by cutting the fibers and the reinforcing fibers. A prepreg (hereinafter abbreviated as PPG) was obtained by performing a cutting process at an angle θ = 45 °. At this time, the total length of cuts per 1 m ² is la = 56.6 m.

PPG and 0.5 mm thick nylon 6 sheet (Nylon 6: manufactured by Ube Industries, product name: 1013B) as shown in Table 1 are stacked in a 300 mm square and 1.5 mm deep stamping mold and heated. , Using a compression molding machine (product name: SFA-50HH0, manufactured by Shindo Metal Industries, Ltd.), holding at a high temperature side press for 7 minutes under the conditions of 250 ° C. and a hydraulic pressure instruction of 0 MPa, then a hydraulic pressure instruction of 2 MPa at the same temperature ( After holding for 7 minutes under the condition of a press pressure of 0.55 MPa, the mold is moved to a cooling press and held for 3 minutes at 30 ° C. and a hydraulic pressure indication of 5 MPa (press pressure of 1.38 MPa) to provide a carbon fiber reinforced plastic laminate. Obtaining a sheet Using the above sheet, stamping moldability is evaluated.

(Example 2)
A carbon fiber reinforced plastic laminate was prepared in the same manner as in Example 1 except that PPG and 0.5 mm thick nylon 66 sheet (nylon 66: manufactured by DuPont, product name: 101F) were stacked as shown in Table 1. And evaluate. In addition, the sum total of the cut length per 1 m ^{2 of} PPG used for the surface layer at this time is 14.5 = 154.5 m.

(Comparative Example 1)
A carbon fiber reinforced plastic laminate in the same manner as in Example 1 except that PPG and 0.5 mm thick nylon 12 sheet (nylon 12: manufactured by Daicel Eponic, product name: L1600) were stacked as shown in Table 1. Are manufactured and evaluated. In addition, the sum total of the cut length per 1 m ^{2 of} PPG used for the surface layer at this time is 14.5 = 154.5 m.

  As is clear from FIG. 1, Examples 1 and 2 have a small fiber distribution and good mechanical properties. On the other hand, Comparative Example 1 is unsuitable as a structural material because of its large fiber distribution and poor mechanical properties.

Claims (8)

A laminate having at least a three-layer structure, the fiber reinforced thermoplastic resin laminate having the following (A) layer on both surface layers and the following (B) layer between both surface layers.
(A) Layer: A laminate composed of a prepreg in which a reinforced fiber oriented in one direction is impregnated with a thermoplastic resin, and the prepreg has a depth of cut to cut the reinforced fiber in a direction crossing the reinforced fiber. (A) The prepregs constituting the layer (A) are laminated such that the directions of the reinforcing fibers contained in the prepreg are pseudo-isotropic, or the prepregs at 0 degrees and the prepregs at 90 degrees are alternately arranged. Are stacked.
In addition, the incision is linear, the angle between the incision and the reinforcing fiber is not less than 30 ° and not more than 60 °, and the total incision length per 1 m ^{2 of} the prepreg is not less than 20 m and not more than 250 m,
The average fiber length of the reinforcing fibers is 10 mm or more and 50 mm or less.
(B) Layer: A sheet made of a thermoplastic resin composition and / or a sheet made of a filler-containing thermoplastic resin composition, and the melting point TmB of the thermoplastic resin is the heat constituting the prepreg of the layer (A). Ri der melting point TmA or more thermoplastic resins,
The melting point TmB of the thermoplastic resin and the melting point TmA of the thermoplastic resin used in the layer (A) satisfy the following (Formula 2).
TmB−TmA ≧ 30 (Formula 2)   The fiber reinforced thermoplastic resin laminate according to claim 1, wherein a value obtained by dividing the total thickness of the (A) layer by the total thickness of the (B) layer is 0.1 or more and 3 or less. The fiber-reinforced thermoplastic resin laminate according to claim 1 or 2 , wherein the thickness of each surface layer is 0.1 mm or more and 1.5 mm or less, and the total thickness of the (A) layers is 2.5 mm or less. . (A) The fiber reinforced thermoplastic resin laminate according to any one of claims 1 to 3 , wherein the volume content of the reinforcing fibers constituting the layer is 20% or more and 60% or less. The fiber reinforced thermoplastic resin laminate according to any one of claims 1 to 4 , wherein the reinforcing fibers constituting the layer (A) are carbon fibers. The fiber-reinforced thermoplastic resin laminate according to any one of claims 1 to 5 , wherein the single fiber fineness of the reinforcing fibers constituting the layer (A) is 0.5 dtex or more and 2.4 dtex or less. The fiber-reinforced thermoplastic resin laminate according to any one of claims 1 to 6 , wherein the number of filaments in the fiber bundle of reinforcing fibers constituting the layer (A) is 3,000 or more and 100,000 or less. A method for producing the fiber-reinforced thermoplastic resin laminate according to any one of claims 1 to 7,
The (A) layer and the (B) layer are fused by heating above the softening point or melting point of the thermoplastic resin composition constituting the (A) layer and the thermoplastic resin composition constituting the (B) layer. The manufacturing method of a fiber reinforced thermoplastic resin laminated body.