JP6528782B2 - Sheet for fiber-reinforced plastic molding - Google Patents

Description

The present invention relates to a sheet for fiber-reinforced plastic molding. Specifically, the present invention relates to a sheet for a fiber-reinforced plastic molded article having a fiber orientation parameter (fp) of reinforcing fibers in the thickness direction as a specific range.

Fiber reinforced plastic molded articles obtained by heat and pressure treatment of non-woven fabrics containing reinforcing fibers such as carbon fibers and glass fibers are already used in various fields such as sports, leisure goods and aircraft materials. A thermosetting resin such as an epoxy resin, an unsaturated polyester resin, or a phenol resin is often used as a resin to be a matrix in these fiber-reinforced plastic moldings. However, in the case of using a thermosetting resin, the non-woven fabric of the thermosetting resin and the reinforcing fiber before being press-formed must be stored under refrigeration, and has a drawback that long-term storage can not be performed.

For this reason, in recent years, development of a fiber reinforced non-woven fabric containing reinforcing fibers using a thermoplastic resin as a matrix resin has been promoted. A fiber-reinforced nonwoven fabric using such a thermoplastic resin as a matrix resin has the advantages of easy storage management and long-term storage. In addition, non-woven fabrics containing a thermoplastic resin are easier to mold and process as compared with non-woven fabrics containing a thermosetting resin, and have the advantage of being able to mold molded products by heat and pressure treatment. ing.

Heretofore, thermoplastic resins that are inferior to thermosetting resins in terms of chemical resistance and strength have been mainstream. However, in recent years, thermoplastic resins excellent in heat resistance, chemical resistance and the like have been actively developed, and the above-mentioned drawbacks which have been regarded as common knowledge about thermoplastic resins have been remarkably improved. There is. Such a thermoplastic resin is a resin called so-called "emplar (engineering plastic)", and polycarbonate (PC), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamideimide (PAI), polyetherimide (PEI) etc. is mentioned (for example, nonpatent literature 1).

Further, in addition to the use for fiber and plastic in the above-mentioned aircraft and automobiles, since the fiber-reinforced plastic molding is also used for building materials, electrical products and the like, performance for preventing fire due to ignition is also required. For this reason, higher flame retardancy is required for the fiber reinforced plastic molded body. For example, Patent Documents 1 and 2 propose that the flame retardancy of a fiber-reinforced plastic molded body is enhanced by containing a flame retardant in the fiber-reinforced plastic molded body. Moreover, in patent document 2, suppressing the dripping of the polycarbonate at the time of combustion is examined by adding glass fiber.

JP 2002-226697 A Japanese Examined Patent Publication No. 60-16473

"Survey report on application of thermoplastic resin composites to the machine industry field in 2007", Next-generation metal and composite materials research and development association, Japan Mechanical Industry Association, March 2008 issue

As described above, the flame retardancy can be enhanced to some extent by incorporating the flame retardant into the fiber-reinforced plastic molded body. However, in a fiber-reinforced plastic molded product as disclosed in Patent Document 1, a thermoplastic resin or the like melts and drops during combustion, and such a drop may serve as an igniter for another material. It had become. Moreover, also in the fiber reinforced plastic molded object currently disclosed by patent document 2, it became clear by examination of the present inventors that dripping of a thermoplastic resin etc. can not fully be suppressed enough.

Then, in order to solve such a subject of the prior art, the present inventors provide the sheet | seat for the fiber reinforced plastic molded object which can shape | mold the fiber reinforced plastic molded object in which generation | occurrence | production of the dripping thing was suppressed at the time of combustion. The study was advanced for the purpose.

As a result of intensive investigations to solve the above problems, the present inventors have found that the fiber orientation parameter of reinforcing fibers in the thickness direction in a sheet for a fiber-reinforced plastic molded article containing reinforcing fibers and a thermoplastic resin By making fp) into a specific range, it discovered that the non-dropping property of a fiber reinforced plastic molded object could be improved.
Specifically, the present invention has the following configuration.

[1] A sheet for a fiber-reinforced plastic molded article containing a reinforcing fiber and a thermoplastic resin, wherein the thermoplastic resin is a thermoplastic resin having a limit oxygen index of 30 or more, or for a fiber-reinforced plastic molded article The sheet contains a flame retardant, and the fiber reinforced plastic molded article characterized in that the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction in the sheet for fiber reinforced plastic molded article is 0.5 to 1.0. Seat.
[2] The sheet for fiber-reinforced plastic molding according to [1], wherein the thermoplastic resin is a thermoplastic resin containing a flame retardant, when the sheet for fiber-reinforced plastic molding contains a flame retardant.
[3] The sheet for a fiber-reinforced plastic molding according to [1] or [2], wherein the thermoplastic resin is a thermoplastic resin fiber.
[4] A binder component is further included, and the binder component is contained in an amount of 0.1 to 10% by mass based on the total mass of the sheet for a fiber-reinforced plastic molded body according to any one of [1] to [3] Sheet for fiber-reinforced plastic moldings.
[5] The sheet for a fiber-reinforced plastic molded article according to any one of [1] to [4], wherein the mass average fiber length of the reinforcing fibers is 6 to 100 mm.
[6] When the sheet for fiber-reinforced plastic molding contains a flame retardant, the sheet for fiber-reinforced plastic molding according to any one of [1] to [5], wherein the thermoplastic resin is polycarbonate or polyamide.
[7] The sheet for fiber-reinforced plastic molding according to any one of [1] to [6], wherein the thermoplastic resin having a limit oxygen index of 30 or more is polyetherimide.
[8] A sheet for a fiber-reinforced plastic molded body described in any one of [1] to [7] is formed by pressure heating at a temperature higher than the melting point or glass transition temperature of the thermoplastic resin. A fiber-reinforced plastic molded article, wherein the absolute value of the fiber orientation parameter (fp) of reinforcing fibers in the thickness direction in the fiber-reinforced plastic molded article is 0.5 to 1.0. .
[9] The fiber-reinforced plastic molding according to [8], which has a thickness of 0.4 to 1.0 mm.
[10] The fiber-reinforced plastic molding according to [8] or [9], wherein the geometric mean value of the bending strength is 200 MPa or more.
[11] The fiber-reinforced plastic molded article according to any one of [8] to [10], which is formed by heating and pressing at a temperature of 150 to 600 ° C.
[12] A step of wet papermaking of a slurry in which a reinforcing fiber and a thermoplastic resin fiber are mixed, wherein the thermoplastic resin fiber is a thermoplastic resin fiber having a limit oxygen index of 30 or more, or a fiber reinforced plastic molded The body sheet contains a flame retardant, and the step of wet paper making is
(A) a step of making a paper at a machine speed of 5 m / min or more using a yen mesh paper machine, or
(B) A process of making paper using a Fourdrinier paper machine or a inclined paper machine,
When the step of wet papermaking includes (B) a step of making paper using a Fourdrinier paper machine or a slant paper machine, the wire of the Fourdrinier paper machine or the slant paper machine has a jet wire ratio of 0.95 or less And a method of manufacturing a sheet for a fiber-reinforced plastic molded article characterized by traveling as described above.
[13] The method for producing a sheet for fiber-reinforced plastic molding according to [12], wherein the viscosity at 25 ° C. of the dispersion medium of the slurry is more than 1.00 mPa and not more than 4.00 mPa.
[14] The step of wet paper making is a step of making paper using a inclined paper machine. [12] The method for producing a sheet for fiber-reinforced plastic molding according to [12] or [13].

According to the present invention, it is possible to obtain a sheet for a fiber-reinforced plastic molded body capable of forming a fiber-reinforced plastic molded body in which the generation of drips is suppressed at the time of combustion. In the fiber-reinforced plastic molded article formed from the sheet for a fiber-reinforced plastic molded article of the present invention, the flame retardancy is enhanced by sufficiently enhancing the non-dropping property. For this reason, the fiber-reinforced plastic molded article of the present invention is preferably used particularly for aircraft, automobile, building material, electric products, etc. which are required to have functions such as flame retardancy.

FIG. 1 is an image view of a test piece for cross-sectional observation for measuring a fiber orientation parameter of a sheet for a fiber-reinforced plastic molded article of the present invention. FIG. 2 is an image diagram showing the orientation of a part of reinforcing fibers in the conventional fiber-reinforced plastic molded body and the appearance of melting of the thermoplastic resin by igniting the conventional fiber-reinforced plastic molded body. FIG. 3 is an image view showing the orientation of the reinforcing fibers in the fiber-reinforced plastic molded article of the present invention and the appearance of melting of the thermoplastic resin by igniting the fiber-reinforced plastic molded article of the present invention. FIG. 4 is a photograph showing the orientation of reinforcing fibers in the fiber-reinforced plastic molding of the present invention.

Hereinafter, the present invention will be described in detail. The description of the configuration requirements described below may be made based on typical embodiments and specific examples, but the present invention is not limited to such embodiments. In addition, the numerical range represented using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

(Sheet for fiber reinforced plastic molding)
The present invention relates to a fiber-reinforced plastic molded sheet containing reinforcing fibers and a thermoplastic resin. In the present invention, the thermoplastic resin is a thermoplastic resin having a limit oxygen index of 30 or more, or the sheet for fiber reinforced plastic molded body contains a flame retardant. Moreover, the absolute value of the fiber orientation parameter (fp) of the reinforcement fiber of the thickness direction in the sheet | seat for fiber reinforced plastic molded bodies of this invention is 0.5-1.0.

In the present specification, the fiber orientation parameter (fp) of the reinforcing fiber is a parameter that represents the orientation state of the reinforcing fiber in the sheet for fiber-reinforced plastic molded body. The fiber orientation parameter (fp) is a parameter that represents the fiber orientation distribution as a numerical value of −1.0 to 1.0, and when fp = −1.0 and fp = 1.0, the reinforcing fibers are oriented in one direction When fp = 0.0, it means that reinforcing fibers are completely randomly arranged.

In the present invention, the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction in the sheet for a fiber-reinforced plastic molded body may be 0.5 to 1.0. The absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction is preferably 0.6 to 1.0, more preferably 0.7 to 1.0, and 0.8 to 1. More preferably, it is 0. By setting the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction within the above range, the orientation of the reinforcing fiber in the thickness direction can be made constant, and it is molded from the sheet for fiber reinforced plastic Can improve the non-dropping property of the fiber-reinforced plastic molding.
The fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for fiber-reinforced plastic molding can be controlled, for example, by appropriately selecting the method for producing the sheet for fiber-reinforced plastic molding, etc. .

When measuring the fiber orientation parameter (fp) of reinforcing fibers in the thickness direction in a sheet for a fiber-reinforced plastic molded article, an embedding epoxy resin generally used in a sheet for a fiber-reinforced plastic molded article in electron microscopic observation Etc. to make a test piece for cross-sectional observation. Here, the reason for impregnating the embedding epoxy resin is to prevent the orientation direction of the fiber from being changed due to the shear force at the time of cutting when cutting out the cross section described later. As the embedding resin, it is preferable to use an epoxy resin, a styrene resin, or a resin having sufficient strength and hardness to withstand shear force, but in the present invention, by using the epoxy resin, the fiber orientation of reinforcing fibers in the thickness direction Measure the parameter (fp). Examples of the embedding resin include ALONIX LCA D-800 manufactured by Nippon Denshi Co., Ltd. In the case of a thermosetting resin or a resin that generates heat during curing, the adhesive power of the reinforcing fibers of the binder in the sheet for the fiber-reinforced plastic molded body is reduced by the heat during curing, and the angle of the reinforcing fibers changes. there is a possibility. For this reason, it is preferable to use a resin that does not serve as a heat source at the time of curing, such as a photocurable epoxy resin such as ultraviolet light.
As a method of resin embedding, a method generally used in electron microscope observation or optical microscope observation can be adopted. Specifically, the sheet for fiber-reinforced plastic molding is cut into a width of 5 mm and a length of 10 mm, and the above-mentioned embedding epoxy resin is dropped and impregnated until at least the surface of the test piece is completely covered and hardened. Further, dropping of the embedding epoxy resin can be performed using, for example, a dropper or the like.

FIG. 1 is a conceptual view of a test piece for cross-sectional observation obtained by impregnating a sheet for fiber-reinforced plastic molding with an ultraviolet curing type embedding epoxy resin. As shown in FIG. 1A, the test piece 45 for cross-sectional observation includes the reinforcing fiber 20 and the thermoplastic resin 25 constituting the sheet 5 for a fiber-reinforced plastic molded body, and the epoxy resin 40 for embedding. Do. In the cross-sectional observation test piece 45, the positional relationship and the shape of the reinforcing fiber 20 and the thermoplastic resin 25 are the same as those in the sheet 5 for a fiber-reinforced plastic molded body. That is, in the cross-sectional observation test piece 45, the embedding epoxy resin 40 is present so as to maintain the positional relationship and the shape of the reinforcing fiber 20 and the thermoplastic resin 25.

In FIG. 1 (a), the thermoplastic resin 25 is shown in the form of fibers, but in fact, it may not be in the form of fibers but may be in the form of particles as described later. When the thermoplastic resin 25 is in the form of fibers as shown in FIG. 1A, it looks like the shape of the reinforcing fibers 20 and is not distinguishable. However, when observing the orientation state of the reinforcing fiber, it is possible to observe the orientation of only the reinforcing fiber by utilizing the difference in fiber diameter, the difference in color of the fiber, the element mapping or the like.

When observing the fiber orientation in the thickness direction, a test piece having a width of 0.3 mm to 0.6 mm is cut out from the test piece for cross-sectional observation, and the cross section in the thickness direction of the obtained test piece is observed with an optical microscope. As a method of cutting out, a method of vertically cutting with a thin sharp blade such as a safety razor or a surgical knife may be employed. However, since it is difficult to obtain a vertical cross section manually, it is also possible to use a film slicer for cutting a section for FT-IR measurement or the like, or an ion slicer for cutting a section for electron microscope observation. As a film slicer, Slice Master HS-1 manufactured by JASCO Corp. is exemplified, and as an ion slicer, EM-09100IS manufactured by Nippon Denshi Co., Ltd. is exemplified. Here, the cutting direction of the test piece is a direction parallel to the reference line in the plane direction obtained by the method described later. As the optical microscope, a microscope made by Keyence Corporation is used to observe the fiber by magnifying the monofilament to a visible magnification. When the reinforcing fibers are not transparent fibers (for example, in the case of carbon fibers), the reinforcing fibers can be observed by transmitted light. In the present embodiment, for example, the magnification can be selected from 300 times, 600 times, and 800 times. In addition, the observation of the reinforcing fiber is performed by focusing on a portion having a depth of 10 μm or more from each of the observation surface of the test piece and the opposite surface thereof. The test piece may be cut out using a microtome.
In the present invention, by embedding in an epoxy resin and cutting out a cross section in the thickness direction, it is possible to prevent the change in the angle of the fiber due to the shear force at the time of cutting.

When the reinforcing fiber is an opaque fiber such as a carbon fiber, the orientation direction of the reinforcing fiber can be observed by the difference in the chromaticity of the fiber when observed with an optical microscope. For example, when observing carbon fibers, black fibers can be observed as reinforcing fibers.

When a transparent reinforcing fiber or the like such as glass fiber is used, the interface between the reinforcing fiber and the resin may not be clearly visible even when observed with an optical microscope as described above. In such a case, the sheet for the fiber-reinforced plastic molding is embedded with an epoxy resin in the same manner as described above, cut out so that the cross section of the test piece for cross-section observation is exposed, and then element mapping is performed to orient the reinforcing fibers. Can be observed. In this case, the element to be mapped is an element containing only reinforcing fibers and not containing a thermoplastic resin and an epoxy resin. For example, in glass fiber, fiber orientation can be measured by mapping Si or Ca element by an electron microscope equipped with an energy dispersive X-ray analysis (EDS / EDX: Energy Dispersive X-Ray Spectroscopy) apparatus. . As such an apparatus, a desk-top scanning electron microscope “PRO X” manufactured by Dutch Phenom World, etc. is exemplified.

The orientation direction of the reinforcing fibers is the longitudinal direction of the reinforcing fibers. In addition, in the cross section in the thickness direction, the reinforcing fibers may be confirmed to be elliptical. When the reinforcing fiber is confirmed to be elliptical, the major axis direction of this ellipse is taken as the fiber orientation direction. The orientation angle θi of the reinforcing fiber is an angle formed by the orientation direction (alignment line) of the selected reinforcing fiber with respect to the reference line. In the present invention, the cross section in the thickness direction of the test piece is observed with an optical microscope or the like under the above conditions, and a continuous 1.5 mm ² measurement area arbitrarily selected from the above cross sections is observed. Measure the orientation angle θi of all visible fibers (the number of fibers is n) present in. The orientation angle θi measures the angle in the clockwise direction with respect to the reference line, and is an angle of 0 ° or more and less than 180 °.

The fiber orientation parameter in the thickness direction (fp, hereinafter also referred to as fp value) can be calculated from the orientation angle θi measured by the above method using the following equation (1).
fp = 2 × Σ (cos ² θ _i / n) −1 Formula (1)
Here, θ _i is the orientation angle (i = 1 to n) of the selected reinforcing fiber with respect to the reference line.

Here, the reference line can be determined by the following method.
In setting a reference line, first, a temporary reference line p is selected, and the angles of all n visible reinforcing fibers present in the measurement area are measured. In this case, the provisional reference line p and the angle of each fiber are represented by α (p) _i (i = 1 to n).
The fiber orientation parameter (fp (p)) at the time of using the temporary reference line p can be calculated using the following equation.
fp (p) = 2 × Σ (cos ² α (p) _i / n) −1
(I = 1, 2, 3, ..., n)
Next, the temporary reference line p is rotated by ± 1 ° to ± 90 ° and the temporary reference line (p _{+ z} , p _−z (z = 1 to 90)) is taken, and the temporary reference line p _{+ z} And the angle of the provisional reference line p _−z and the n fibers are calculated. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to n).
The rotated temporary reference line (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber can be calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / n) -1
(I = 1, 2, 3, ..., n)
Thus, the temporary reference line set when the maximum value is obtained among the obtained fp (p) value and the absolute value of fp (p ± _z ) value can be used as the reference line P. The fiber orientation parameter calculated from the reference line P thus determined can be used as the fiber orientation parameter (fp) in the thickness direction.

FIG. 1B is a conceptual cross-sectional view in which the test piece 45 for cross-sectional observation shown in FIG. 1A is cut out in the BB ′ direction and the thickness direction is a vertical direction. The BB ′ direction is preferably a direction parallel to the direction in which the majority of the fibers are oriented. That is, the BB ′ direction is a direction parallel to the reference line in the planar direction obtained by the method described later.
In FIG. 1 (b), the reference line determined by the above method is a dotted line represented by P, and the orientation of each reinforcing fiber is represented by a dotted line of Q and R, respectively. In FIG. 1 (b), the dotted line P 'is a line parallel to the reference line, and the angle formed by the reference line P and the orientation line (Q and R) of each reinforcing fiber can be easily understood. It is an auxiliary line. In FIG. 1 (b), since the angle formed by P ′ and Q (alignment angle θ ₁ ) is 0 °, P ′ and Q overlap. Further, an angle formed between P ′ and R (orientation angle θ ₂ ) is represented as θ ₂ . Thus, θ ₁ to θ _n are measured. In addition, in FIG.1 (b), in order to make it easy to confirm the orientation state of a reinforced fiber, only the reinforced fiber is shown in figure.

As a part to measure the fiber orientation parameter (fp) or the provisional reference line and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber, avoid the end of the cross section in the thickness direction of the cross-section observation test piece It is preferable to be in the vicinity of the center. Specifically, it is preferable to avoid the area up to 5% (5% with respect to the thickness of the test piece for cross-section observation) in the thickness direction from both sides of the test piece for cross-section observation as a measurement area.

In the present invention, that the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction is within the above range is oriented so that the angle between the reinforcing fiber and the center plane of the fiber-reinforced plastic molding is small. Means to Specifically, the fact that the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction is within the above range means that the sheet for fiber-reinforced plastic molding is heated and pressed under the following conditions (a) and (b) In this case, in the obtained fiber reinforced plastic molded article having a thickness of 1 mm, it means that most of the reinforcing fibers among the reinforcing fibers are present substantially parallel to the center plane of the fiber reinforced plastic molded article.
(A) The press pressure is 10 MPa, and the press speed is 3.5 cm / sec.
(B) A fiber obtained when the true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molding is P, and the sheet for the fiber-reinforced plastic molding is heated while being pressurized under the condition of the above (a) When the bulk density (g / cm ³ ) of the reinforced plastic molding is Q, heating is performed so that Q / PP0.7.

The term "most reinforcing fibers" means 80% or more of the total number of reinforcing fibers. Further, "substantially parallel to the center plane of the fiber-reinforced plastic molding" means that the angle between the center plane of the fiber-reinforced plastic molding and the reinforcing fiber is oriented within ± 20 °. That is, in a fiber-reinforced plastic molded article having a thickness of 1 mm obtained by heat and pressure molding under the above conditions (a) and (b), 80% or more of the total number of reinforcing fibers are fiber-reinforced plastic molded articles It is characterized in that it is oriented so that the angle formed with the central plane is within ± 20 °.

In the fiber-reinforced plastic molded sheet of the present invention, in the fiber-reinforced plastic molded body, an angle of 80% or more of the total number of reinforcing fibers with the center plane of the fiber-reinforced plastic molded body is within ± 20 ° Orientation. In the present invention, preferably 85% or more, more preferably 90% or more, of the total number of reinforcing fibers are oriented such that the angle between the fiber reinforced plastic molded body and the center plane is within ± 20 °. . That is, most of the reinforcing fibers are parallel to the center plane of the fiber-reinforced plastic molding. For this reason, on the center plane of the fiber-reinforced plastic molding and a plane parallel thereto, the density of the reinforcing fiber becomes high, and excellent bending strength can be obtained. Furthermore, by setting it as the above fiber orientation, even if it is a case where a fiber reinforced plastic molded object is exposed to a flame, generation | occurrence | production of the dripping thing derived from a thermoplastic resin can be suppressed.

Here, the center plane of the fiber-reinforced plastic molding refers to a plane formed by connecting the middle point of the average plane of the first surface and the average plane of the second surface of the fiber-reinforced plastic molding. The mean surface of the first surface and the midpoint of the mean surface of the second surface are the midpoint of the shortest distance between the specific point on the mean surface of the first surface and the mean surface of the second surface. Say In addition, the average surface of each surface means the surface passing through the average height of the heights of the concave and convex portions if the surface has an uneven shape, and if there is no uneven surface, each average surface is It means the surface.

FIG. 2 is a view showing the orientation of reinforcing fibers in a plane parallel to the surface of the conventional fiber-reinforced plastic molding 101. As shown in FIG. As shown in FIG. 2, in the conventional fiber reinforced plastic molded body 101, reinforcing fibers 20 oriented in a direction parallel to the surface of the fiber reinforced plastic molded body 101, and the fiber reinforced plastic molded body 101. There are reinforcing fibers 20 'oriented in a direction perpendicular to the surface. Besides, there are also many reinforcing fibers having an angle with the surface of the fiber reinforced plastic molded body 101.

As shown in FIG. 2 (a), when the flame 50 is brought into contact with the conventional fiber reinforced plastic molded body 101, as shown in FIG. 2 (b), the conventional fiber reinforced plastic molding is performed. Drops 60 of the melted thermoplastic resin drop from the body 101. In addition, the dripping situation of the plastic molding at the time of such combustion makes the fiber reinforced plastic molding 101 cut out to be a predetermined size indirectly a blue flame of 20 mm length specified in the UL94 flammability test for 10 seconds. It can be evaluated by burning. Specifically, the dropping state can be evaluated by the evaluation method described in the examples.
In the conventional fiber reinforced plastic molded body 101, many reinforcing fibers are oriented in the direction perpendicular to the surface, and the density of the reinforcing fibers on the surface parallel to the surface is low. In addition, the distance between the reinforcing fibers is increased by the reinforcing fibers 20 'oriented in the vertical direction being inserted between the reinforcing fibers 20 oriented in parallel to the surface of the fiber-reinforced plastic molded body 101. . For this reason, the number of reinforcing fibers with which the melted thermoplastic resin comes in contact decreases, and the surface tension of the melted thermoplastic resin does not work sufficiently, and the droplets 60 of the melted thermoplastic resin are dropped.

FIG. 3 is a view showing the orientation of reinforcing fibers in a cross section parallel to the surface of the fiber-reinforced plastic molded body 100 according to an embodiment of the present invention. As shown in FIG. 3, in the fiber-reinforced plastic molded body 100 of the present invention, most of the reinforcing fibers 20 are oriented in a direction parallel to the surface of the fiber-reinforced plastic molded body 100.

As shown in FIG. 3 (a), even when a flame 50 is brought into contact with the fiber-reinforced plastic molding 100 of the present invention, as shown in FIG. 3 (b), It is difficult for the drop 60 of the melted thermoplastic resin to drip from the fiber-reinforced plastic molded body 100 of the invention.
In the fiber-reinforced plastic molded body 100 of the present invention, the density of reinforcing fibers on the surface parallel to the surface is high with less reinforcing fibers oriented in the direction perpendicular to the surface. Further, the reinforcing fibers 20 oriented in the direction parallel to the surface are arranged without gaps, and the distance between the reinforcing fibers is short. For this reason, the number of reinforcing fibers with which the melted thermoplastic resin is in contact increases, the surface tension of the thermoplastic resin works, and the dripping of the melted thermoplastic resin droplet 60 can be suppressed. Thereby, the non-dropping property of the fiber reinforced plastic molded body is improved, and as a result, the flame retardancy is enhanced.

As described above, in the fiber-reinforced plastic molded article of the present invention, the non-dropping property can be improved by defining the orientation direction of the reinforcing fiber in the thickness direction. For this reason, in the fiber-reinforced plastic molded body of the present invention, the flame retardancy is enhanced, and when the sheet for fiber-reinforced plastic molded body contains a flame retardant, the amount of the flame retardant to be added can be reduced. As such, it is not necessary to add a large amount of flame retardant. As a result, it is possible to obtain a fiber-reinforced plastic molded body which maintains the inherent properties of the thermoplastic resin. When a thermoplastic resin having a critical oxygen index of 30 or more is used as a thermoplastic resin, it is possible to use a thermoplastic resin having a critical oxygen index of less than 30 in combination, and even in such a case, it is not possible. The dripping property can be improved.

In a fiber-reinforced plastic molded article having a thickness of 1 mm obtained by heat-pressing the sheet for a fiber-reinforced plastic molded article of the present invention under the above conditions (a) and (b), the synergistic average value of bending strength is 200 MPa It is preferable that it is more than. The geometric mean value of the bending strength is preferably 200 MPa or more, and more preferably 220 MPa or more. Thus, since the density of reinforcing fibers on the surface parallel to the surface of the fiber-reinforced plastic molding is high, the fiber-reinforced plastic molding obtained in the present invention is excellent in mechanical strength.
Here, the geometric mean value of the bending strength is a geometric mean value of the bending strength in the direction (CD direction) orthogonal to the orientation direction of the fiber (MD direction) and the orientation direction of the reinforcing fiber in the fiber reinforced plastic molded body, It means the strength represented by the following equation.
Geometrical mean value of bending strength = ((FMD x FCD)
Here, FMD represents bending strength in the FD direction, and FCD represents bending strength in the CD direction.

Moreover, the absolute value of the fiber orientation parameter (fp) in the planar direction in the sheet for fiber-reinforced plastic molding may be 0 to 1.0. The absolute value of the fiber orientation parameter (fp) in the planar direction in the sheet for fiber-reinforced plastic molding may be 0.18 to 1.0, may be 0.25 to 1.0, and 0. 0. It may be 3 to 1.0, or may be 0.6 to 1.0. That is, in the sheet for fiber-reinforced plastic molded bodies of the present invention, in addition to the fact that the orientation in the thickness direction is a constant direction, the orientation in the planar direction may also be a constant direction.

In such a case, the reinforcing fibers are parallel to the center plane of the fiber-reinforced plastic molding and are oriented in one direction also in the planar direction. The reinforcing fibers may be oriented in any direction of the plane direction of the fiber-reinforced plastic molded body, but it is preferable to be oriented in the MD direction of the fiber-reinforced plastic molded body (flowing direction of the paper making line). That is, in the fiber-reinforced plastic molded article obtained by molding the sheet for fiber-reinforced plastic molded article of the present invention under specific conditions, the reinforcing fibers are parallel to the center plane and in the MD direction (flow of the papermaking line Orientation).

The measurement of the fiber orientation parameter of the reinforcing fibers in the planar direction in the sheet for fiber-reinforced plastic molded articles can be measured without particularly performing processing such as resin embedding. Specifically, a sheet for a fiber-reinforced plastic molded body cut out into 3 cm in length x 3 cm in width is placed on a slide glass, a slide glass is further placed from above, and observation is performed by measurement of ordinary reflected light using a microscope. can do.
In the present invention, one side of the test piece sandwiched by the slide glass is observed with an optical microscope. A microscope manufactured by Keyence Corporation is used as an optical microscope, and the fiber is observed with a reflected light by enlarging it to a magnification at which a monofilament can be visually recognized, or a combination of a reflected light and a transmitted light. In the present embodiment, for example, the magnification can be selected from 300 times, 600 times, and 800 times. Thereby, the continuous 2.0 mm ² measurement area selected arbitrarily on one side is observed, and all visible reinforcing fibers present in this measurement area (the number of fibers is m) Measure the orientation angle θi of The orientation angle θi measures the angle in the clockwise direction with respect to the reference line, and is an angle of 0 ° or more and less than 180 °. The fiber orientation parameter (fp, hereinafter also referred to as fp value) can be calculated from the orientation angle θi measured by the above method using the following equation (2).
fp = 2 × Σ (cos ² θ _i / m) −1 Formula (2)
However, i is 1 to m.
Then, the opposite surface is also measured in the same manner, the average value of one surface and the opposite surface is determined, and this is used as the fiber orientation parameter (fp) in the planar direction. The measurement area on one side and the measurement area on the opposite side are, for example, areas overlapping in plan view. In addition, in any observation of one side and the opposite side, for example, it is possible to focus and observe a portion having a depth of 10 μm or more from each of the one side and the opposite side.

The reference line when measuring the fiber orientation parameter in the planar direction can be determined by the following method.
In setting a reference line, first, a temporary reference line p is selected, and the angles of m visible reinforcing fibers present in the measurement area are measured. In this case, the provisional reference line p and the angle of each fiber are represented by α (p) _i (i = 1 to m).
The fiber orientation parameter (fp (p)) at the time of using the temporary reference line p can be calculated using the following equation.
fp (p) = 2 ×× (cos ² α (p) _i / m) −1
(I = 1, 2, 3 ... m)
Next, the temporary reference line p is rotated by ± 1 ° to ± 90 ° and the temporary reference line (p _{+ z} , p _−z (z = 1 to 90)) is taken, and the temporary reference line p _{+ z} And the angle of temporary reference line p- _z and m fibers is calculated. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to m).
The rotated temporary reference line (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber can be calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / m) -1
(I = 1, 2, 3 ... m)
Thus, the provisional reference line set when the maximum value is obtained among the obtained fp (p) value and fp (p ± _z ) value can be used as the reference line P. The fiber orientation parameter calculated from the reference line P determined in this manner can be taken as the fiber orientation parameter (fp) in the planar direction.

When the orientation of the reinforcing fiber in the thickness direction and the plane direction is a constant direction, in the fiber-reinforced plastic molded article obtained by forming the sheet for a fiber-reinforced plastic molded article, the non-dropping property is more effectively enhanced. The flame retardancy of the molded body is enhanced. Moreover, in the fiber reinforced plastic molded body, bending strength in one direction is enhanced. In particular, when the reinforcing fibers are oriented in the MD direction, the strength in the MD direction is enhanced in the fiber-reinforced plastic molded body. Such a fiber-reinforced plastic molded body is preferably used for structural parts that are required to have mechanical strength in one direction, which is used for automobiles, aircrafts, and the like.

In the sheet for fiber-reinforced plastic molded articles of the present invention, the blending ratio of the reinforcing fibers is preferably 20 to 83% by mass. By setting the blending ratio of the reinforcing fibers within the above range, it is possible to increase the number of fibers oriented in a specific direction. As a result, the distance between the reinforcing fibers becomes short, the packing density of the reinforcing fibers after the heat and pressure molding becomes high, and the strength of the fiber-reinforced plastic molding can be effectively enhanced.

The mass ratio of the reinforcing fiber to the thermoplastic resin is preferably 1: 0.2 to 1:10, more preferably 1: 0.5 to 1: 5, 1: 0.7 to 1 More preferably, it is 3. By setting the mass ratio of the reinforcing fiber to the thermoplastic resin in the above range, it is possible to obtain a fiber reinforced plastic molded article that is lightweight and has high strength.

JAPAN TAPPI Paper and pulp test method No. of fiber reinforced plastic molded sheet The air permeability defined in 5-2 is preferably 250 seconds or less, more preferably 230 seconds or less, and still more preferably 200 seconds or less. This figure represents that the smaller the figure, the easier the air will pass (the better the air permeability). In the present invention, by setting the air permeability of the sheet for fiber reinforced plastic molded body within the above range, the molding speed in the heating and pressing step can be increased, and the production efficiency can be improved.

(Reinforcing fiber)
The reinforcing fiber is preferably at least one selected from glass fiber, carbon fiber and aramid fiber, and more preferably carbon fiber. These reinforcing fibers may be used alone or in combination of two or more. Moreover, you may contain the organic fiber excellent in heat resistance, such as PBO (poly para phenylene benzoxazole) fiber.

When inorganic fibers such as carbon fibers and glass fibers are used as the reinforcing fibers, for example, the fiber reinforced plastic molded body is obtained by heat and pressure treatment at the melting temperature of the thermoplastic resin contained in the sheet for fiber reinforced plastic molded body. It becomes possible to form. In addition, when organic fibers such as aramid are used as the reinforcing fibers, the wear resistance can be improved more than that of a molded article generally formed from a sheet for a fiber-reinforced plastic molded body using inorganic fibers as the reinforcing fibers. .

The mass average fiber length of the reinforcing fiber is preferably 3 to 100 mm, more preferably 6 to 100 mm, still more preferably 6 to 75 mm, and particularly preferably 6 to 50 mm. By setting the fiber length of the reinforcing fiber within the above range, it is possible to suppress the reinforcing fiber from falling off from the sheet for a fiber-reinforced plastic molded body, and to form a fiber-reinforced plastic molded body excellent in strength. Is possible. Moreover, the dispersibility of a reinforcement fiber can be made favorable by making the fiber length of a reinforcement fiber into the said range. Thereby, the fiber reinforced plastic molded body after the heat and pressure molding has good strength and appearance.
In addition, in this specification, mass mean fiber length is an average value of the fiber length measured about 100 fibers.

The fiber diameter of the reinforcing fiber is not particularly limited as the average fiber diameter, but generally, a fiber having a fiber diameter of about 5 to 25 μm is suitably used for both carbon fiber and glass fiber. Further, the reinforcing fiber may use a plurality of materials and shapes in combination.
In addition, in this specification, an average fiber diameter is an average value of the fiber diameter which measured the fiber diameter of 100 fibers.

(Carbon fiber)
It is preferable to use carbon fiber as the reinforcing fiber. When carbon fibers are used, it is possible to form a fiber-reinforced plastic molding excellent in strength. As carbon fibers contained in the reinforcing fibers, carbon fibers of polyacrylonitrile (PAN), petroleum / coal pitch, rayon, lignin, etc. can be used. These carbon fibers may be used alone or in combination of two or more. Further, among these carbon fibers, it is preferable to use a polyacrylonitrile (PAN) -based carbon fiber from the viewpoint of productivity and mechanical properties on an industrial scale.

The mass average fiber length of the carbon fiber is preferably 3 to 100 mm, more preferably 6 to 100 mm, still more preferably 6 to 75 mm, and particularly preferably 6 to 50 mm. By setting the fiber length of the carbon fiber within the above range, it is possible to suppress the carbon fiber from falling off from the sheet for a fiber-reinforced plastic molded body, and to form a fiber-reinforced plastic molded body excellent in strength. Is possible. Moreover, the dispersibility of a reinforced fiber can be made favorable by carrying out the fiber length of carbon fiber in the said range. Thereby, the fiber reinforced plastic molded body after the heat and pressure molding has good strength and appearance.

The single fiber strength of the carbon fiber is preferably 4500 MPa or more, and more preferably 4700 MPa or more. Monofilament strength refers to the tensile strength of the monofilament. When such a carbon fiber is used, the bending strength is greatly improved by the synergetic effect with the effect of the fiber orientation of the reinforcing fiber described above. In addition, single fiber strength can be measured according to JIS R7601 "carbon fiber test method".

The fiber diameter of the carbon fiber is not particularly limited, but generally 5 to 20 μm is preferable as a preferable range. By setting the fiber diameter of the carbon fiber within the above range, the strength of the fiber-reinforced plastic molding can be enhanced.

(Orientation of reinforcing fibers)
In the sheet for fiber-reinforced plastic molding of the present invention, the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction is 0.5 to 1.0. That is, in the sheet for fiber-reinforced plastic molded articles of the present invention, the orientation of the reinforcing fibers in the thickness direction is a constant direction.

In a 1 mm-thick fiber-reinforced plastic molded article obtained by heating and pressing such a sheet for a fiber-reinforced plastic molded article under conditions (a) and (b), 80% or more of the total number of reinforcing fibers is The angle with the center plane of the fiber-reinforced plastic molding is within ± 20 °. Here, conditions (a) and (b) are as follows.
(A) The press pressure is 10 MPa, and the press speed is 3.5 cm / sec.
(B) A fiber obtained when the true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molding is P, and the sheet for the fiber-reinforced plastic molding is heated while being pressurized under the condition of the above (a) When the bulk density (g / cm ³ ) of the reinforced plastic molding is Q, heating is performed so that Q / PP0.7.

The condition (a) defines the pressure condition, and is a pressure condition in which the press pressure is 10 MPa and the press speed is 3.5 cm / sec. The pressing time is not particularly limited, but the sheet for fiber-reinforced plastic molding is heated and pressed under the conditions of (a) and (b) and the press is pressed until it stops. After the temperature rises to the set temperature, the temperature is held for 5 minutes and cooled to a predetermined temperature.

In condition (a), the press speed is 3.5 cm / sec. If the pressing speed is in the range of 3.5 ± 0.5 cm / sec, the same pressing conditions as in the case of pressing at a pressing speed of 3.5 cm / sec are obtained. Since the sheet for fiber-reinforced plastic molded articles of the present invention originally has less orientation of reinforcing fibers in the thickness direction, the orientation of reinforcing fibers in the thickness direction in the molded article is reduced even when pressed at a relatively high pressing speed. By setting the pressing speed to 3.5 cm / sec, it is possible to appropriately evaluate the fiber orientation of the reinforcing fiber in the fiber reinforced plastic molded body.

The condition (b) defines the heating condition, and the true density (g / cm ³ ) of the sheet for the fiber-reinforced plastic molding is P, and the sheet for the fiber-reinforced plastic molding is the condition of the above (a) It is the conditions heated so that it may become Q / P> = 0.7, when the bulk density (g / cm < ³ >) of the fiber reinforced plastic molded object obtained at the time of heating is set to Q, pressurizing.

P, which is the true density (g / cm ³ ) of the sheet for fiber-reinforced plastic moldings, is the density of the solid itself without voids, and is said to be the theoretical density. Also, Q, which is the bulk density (g / cm ³ ) of the fiber-reinforced plastic molding, refers to the mass per unit volume of the plastic molding, including both air permeability and non-air permeability, for fiber reinforced plastic molding It can be calculated by dividing the mass of the sheet by the appearance volume.

The true density of the sheet for fiber-reinforced plastic molding can be determined from the true density of the fibers themselves constituting the non-woven fabric and the mass ratio thereof. Specifically, the true density of the sheet for fiber reinforced plastic molded articles can be calculated by the following formula.
True density of sheet for fiber-reinforced plastic molding = (true density of reinforcing fiber x mass ratio) + (true density of thermoplastic resin x mass ratio) + (true density of binder x mass ratio)

Further, the true density of the sheet for fiber-reinforced plastic molded body may be determined using a pycnometer method (liquid phase replacement method) or a gas phase replacement method, in addition to the above method.
The pycnometer method (liquid phase substitution method) is a method based on JIS R 1620 “Method for measuring particle density of fine ceramic powder”, and the sheet for a fiber-reinforced plastic molding is immersed in a solution such as aqueous ethanol solution or butanol, and the principle of Archimedes Is a method of measuring the volume. The true density of the sheet for fiber-reinforced plastic molding can be calculated by dividing the weight of the sheet for fiber-reinforced plastic molding by the volume measured by the above method.
Further, the vapor phase substitution method is a method based on JIS R 1620 “Method of measuring particle density of fine ceramic powder”, which is a method of measuring volume by substitution with helium gas or the like. The true density of the sheet for fiber-reinforced plastic molding can be calculated by dividing the weight of the sheet for fiber-reinforced plastic molding by the volume measured by the above method.

The bulk density of the fiber-reinforced plastic molding can be determined by the following procedure.
(1) Layering of the fiber reinforced plastic molded sheet is performed as follows. Basis weight (g / m ² ) = true density (g / cm ³ ) × 1 (mm) × 1000
(2) The laminate of the sheet for fiber-reinforced plastic molding according to (1) is heat and pressure molded so as to have a predetermined thickness, and the obtained molded product is cut out so as to be about 10 to 15 cm x 10 to 15 cm. .
(3) Measure the length (cm) and width (cm) of the obtained molded body with a caliper. In addition, the thickness is measured with a micrometer at a total of five points at the four sides and the center, and the average value (μm) of the thickness is determined.
(4) The mass of the molded body is measured in units of 0.1 g.
(5) From the obtained data, the bulk density is determined by the following equation: Bulk density (g / cm ³ ) = weight of molded body (g) ÷ (length of molded body (cm) × width of molded body (cm) × thickness (Μm) × 10 ^-4 )

When heat and pressure molding a fiber reinforced plastic molded body from a sheet for fiber reinforced plastic molded body, the above-mentioned process conditions (a) and (b) are simultaneously performed. Specifically, the heating and pressurizing process is performed simultaneously so as to satisfy the pressurizing condition of (a) and the heating condition of (b). The heat and pressure treatment is a treatment in which a stainless steel plate is disposed in parallel with each surface of the sheet for a fiber-reinforced plastic molding and heat pressing is performed. Here, the stainless steel plate to be used is a stainless steel plate with a thickness of 2 mm which has been surface-finished according to JIS G4305 "Cold-rolled stainless steel plate and steel strip" in Table 15 # 400. Further, at the time of heat pressing, it is preferable to sandwich a spacer plate (1 mm thick plate) at both ends. Thereby, a fiber-reinforced plastic molding having a thickness of 1 mm can be formed.
Moreover, when performing the heating-pressing process mentioned above, it is preferable to heat a heat press machine to 40 degreeC previously.

When the thermoplastic resin is a crystalline thermoplastic resin, the heat press temperature at the time of heat and pressure molding is preferably the melting point (Tm) + 30 ° C. of the thermoplastic resin. When the thermoplastic resin is a non-crystalline thermoplastic resin, the heat press temperature at the time of heat and pressure molding is preferably the glass transition temperature (Tg) of the thermoplastic resin + 100 ° C. The melting point and the glass transition temperature of the thermoplastic resin can be determined by DSC (differential scanning calorimetry).

For example, the heat press temperature of the sheet for fiber reinforced plastic molded articles containing the following thermoplastic resin is as follows. Polycarbonate and polyetherimide are non-crystalline thermoplastic resins, and polypropylene and nylon 6 are crystalline thermoplastic resins.
Polycarbonate: Glass transition temperature Tg 145 ° C, Press temperature 245 ° C
Polyether imide: Glass transition temperature Tg 217 ° C, Press temperature 317 ° C
Polypropylene: Melting point Tm 160 ° C, pressing temperature 190 ° C
Nylon 6: melting point Tm 225 ° C, press temperature 255 ° C

In a fiber-reinforced plastic molded article having a thickness of 1 mm obtained by heating and pressing the sheet for a fiber-reinforced plastic molded article of the present invention under the above conditions, 80% or more of reinforcing fibers are the center of the fiber-reinforced plastic molded article It is oriented parallel to the plane. Such a fiber-reinforced plastic molded body has excellent non-dropping properties and can exhibit excellent bending strength.

In the fiber-reinforced plastic molded body obtained by heat and pressure molding so as to satisfy the above conditions, the ratio of the reinforcing fibers oriented so as to be within ± 20 ° with respect to the center plane is preferably 80% Or more, more preferably 85% or more, still more preferably 90% or more, and particularly preferably 95% or more.
Here, the ratio of reinforcing fibers oriented so as to be within ± 20 ° with respect to the center plane of the fiber-reinforced plastic molding can be determined by the following method. Specifically, a cross section of the fiber-reinforced plastic molded body is cut out and photographed by a three-dimensional measurement X-ray CT apparatus, and 100 to 130 reinforcing fibers are selected from this photographed image to measure the angle formed with the central plane. You can ask for it by doing.

Moreover, the absolute value of the fiber orientation parameter (fp) in the planar direction in the sheet for fiber-reinforced plastic molding may be 0.25 to 1.0. In a fiber-reinforced plastic molded article having a thickness of 1 mm, which is formed by heating and pressing the sheet for such a fiber-reinforced plastic molded article under the conditions (a) and (b), the reinforcing fibers have a center for the fiber-reinforced plastic molded article. It may be parallel to the plane and oriented in one direction. In particular, the reinforcing fibers may be parallel to the center plane for the fiber-reinforced plastic molding and oriented in the MD direction (flow direction of the papermaking line). By thus orienting in the MD direction, it is possible to obtain a substrate for a fiber-reinforced plastic molded article which can form a fiber-reinforced plastic molded article which is excellent in non-dropping properties and excellent in strength in a specific direction.

(Thermoplastic resin)
The thermoplastic resin is preferably a thermoplastic resin having a limiting oxygen index of 30 or more, or, if the sheet for a fiber-reinforced plastic molded body contains a flame retardant, it is preferably a thermoplastic resin containing a flame retardant. In addition, as the thermoplastic resin, a thermoplastic resin having a limiting oxygen index of 30 or more and a thermoplastic resin containing a flame retardant may be used in combination.

The thermoplastic resin may be used in the form of fiber, powder, pellet or flake alone or in combination. Among them, the thermoplastic resin is preferably a thermoplastic resin fiber or a thermoplastic resin powder.

The "thermoplastic resin fiber" in the present specification refers to a fibrous resin among thermoplastic resins. The thermoplastic resin fiber is obtained by melt spinning a thermoplastic resin. The thermoplastic resin fiber containing a flame retardant is obtained by melt-spinning a thermoplastic resin containing a flame retardant. Moreover, the thermoplastic resin fiber containing a flame retardant can also be obtained by mixing and flame | melting a flame retardant and the fuse | melted thermoplastic resin. Further, a thermoplastic resin fiber having a critical oxygen index of 30 or more can be obtained by melt-spinning a thermoplastic resin having a critical oxygen index of 30 or more. In the present invention, the thermoplastic resin fiber is also preferably a chopped strand.

The mass average fiber length of the thermoplastic resin fiber is preferably 3 to 100 mm, more preferably 3 to 50 mm, and still more preferably 3 to 25 mm. By setting the fiber length of the thermoplastic resin fiber within the above range, it is possible to suppress the thermoplastic resin fiber from falling off from the sheet for the fiber reinforced plastic molded body, and for the fiber reinforced plastic molded body excellent in handling property You can get a sheet. Further, by setting the fiber length of the thermoplastic resin fiber within the above range, the dispersibility of the thermoplastic resin fiber can be made favorable, so that it is possible to form a fiber-reinforced plastic molding excellent in strength. Become. Furthermore, by setting the fiber length of the thermoplastic resin fiber within the above range, the thermoplastic resin fiber and the reinforcing fiber are uniformly mixed, and it becomes possible to form a fiber-reinforced plastic molding excellent in strength. Thereby, the fiber reinforced plastic molded body after the heat and pressure molding has good strength and appearance.

The "thermoplastic resin powder" in the present specification refers to a powdery thermoplastic resin. The thermoplastic resin powder is obtained, for example, by freeze-pulverizing thermoplastic resin pellets and performing classification using a mesh. The average primary particle diameter of the thermoplastic resin powder is preferably 3 to 7000 μm, more preferably 30 to 3000 μm, and still more preferably 100 to 1000 μm. In the case where the thermoplastic resin powder is not spherical, the average primary particle diameter of the thermoplastic resin powder is determined by transmission electron micrographs of the projected area of the particles, and the diameter of a circle having the same area is determined as an average primary particle. Let the diameter. By setting the average primary particle diameter of the thermoplastic resin powder in the above range, it is possible to form a net, and it is possible to obtain a sheet for a fiber-reinforced plastic molding by a wet non-woven method. In addition, since the dispersibility of the thermoplastic resin powder can be improved, it is possible to form a fiber-reinforced plastic molding excellent in strength. Thereby, the fiber reinforced plastic molded body after the heat and pressure molding has good strength and appearance.

As a thermoplastic resin having a limit oxygen index of 30 or more, a resin called a so-called super engineering plastic resin can be used. As thermoplastic resins having a limit oxygen index of 30 or more, for example, polyetheretherketone (PEEK), polyamideimide (PAI), polyphenylene sulfide (PPS), polyetherimide (PEI), polyetherketoneketone (PEKK), etc. Can be mentioned. Among them, polyether imide (PEI) is preferably used. Such super engineering plastic fibers can provide flame retardancy without providing a flame retardant as the resin alone. In the present invention, the "limit oxygen index" refers to the oxygen concentration necessary to continue combustion, and refers to a numerical value measured by the method described in JIS K7201. That is, the limit oxygen index of 20 or less is a numerical value indicating that combustion is performed in normal air.

When the sheet for fiber-reinforced plastic molding contains a flame retardant, examples of the thermoplastic resin include polyester, polyethylene, polypropylene, polycarbonate (PC), polyamide (nylon 6, nylon 66), ABS resin, and the like. Among them, polycarbonate (PC) and polyamide (nylon 6, nylon 66) are preferably used. Polycarbonate is preferable because it is excellent in flexural strength, elastic modulus, impact resistance and the like, and can form a fiber-reinforced plastic molded article having high strength even if it is lightweight.

Also in a thermoplastic resin containing a flame retardant, its limit oxygen index is preferably at least a certain value. Specifically, the limit oxygen index in the fiber state is preferably 24 or more, and more preferably 27 or more. By making the limiting oxygen index of the thermoplastic resin containing a flame retardant into the above range, a sheet for a fiber-reinforced plastic molded article and a fiber-reinforced plastic molded article which are more excellent in flame retardancy can be obtained.

The glass transition temperature of the thermoplastic resin is preferably 140 ° C. or higher. Thermoplastic resins are required to be sufficiently fluid under temperature conditions such as 300 ° C. to 400 ° C. when forming a fiber-reinforced plastic molding. In addition, even if it is a super engineering plastic fiber whose glass transition temperature is less than 140 ° C. like PPS resin fiber, any fiber can be used as long as the fiber has a super engineering plastic whose deflection temperature under load of resin is 190 ° C. or higher. Such a thermoplastic resin is melted by heating and pressing to form a resin block having a very high flame retardancy of a critical oxygen index of 30 or more.

The thermoplastic resin is also called a matrix resin because it forms binding points at the intersections of the matrix or the fiber components at the time of heat and pressure treatment. A non-woven sheet for a fiber-reinforced plastic molded article using such a thermoplastic resin does not require autoclave treatment as compared to a sheet using a thermosetting resin, and the heat and pressure molding time for processing is short. It can save time and increase productivity.

In the sheet for fiber-reinforced plastic molding used in the present invention, the thermoplastic resin is preferably in the form of fibers, and in such a case, a void is present in the sheet.
When the thermoplastic resin is in the form of fibers, the thermoplastic resin fibers maintain the form of fibers before heat and pressure molding, so the sheet itself is flexible before the fiber-reinforced plastic molding is formed. It is drapable. For this reason, it is possible to store and transport the sheet for fiber reinforced plastic molded bodies in the form of winding, and it is characterized by being excellent in the handling property.

(Flame retardants)
As the flame retardant, for example, a halogen-based flame retardant, a phosphorus-based flame retardant, or a silicone-based flame retardant can be blended.
Preferred specific examples of the halogen-based flame retardant include brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol A, glycidyl brominated bisphenol A, pentabromobenzyl Polyacrylates, brominated imides and the like can be mentioned, and among them, brominated polycarbonate, brominated polystyrene resin, glycidyl brominated bisphenol A, pentabromobenzyl polyacrylate tends to easily suppress a drop in impact resistance and is more preferable. .
Examples of phosphorus-based flame retardants include metal salts of ethyl phosphinate, metal salts of diethyl phosphinate, melamine polyphosphate, phosphate esters, phosphazene and the like, among which diethyl phosphinate metal salts, melamine polyphosphate, phosphazene are heat It is preferable from the point which is excellent in stability. In addition, in order to suppress generation of gas and mold deposit during molding and bleed out of the flame retardant, a thermoplastic resin having excellent compatibility with the phosphorus flame retardant may be blended. As such a thermoplastic resin, Preferably, they are polyphenylene ether resin, a polycarbonate resin, and a styrene resin.

Furthermore, a flame retardant auxiliary may be mixed with the flame retardant. Examples of the flame retardant auxiliary include copper oxide, magnesium oxide, zinc oxide, molybdenum oxide, zirconium oxide, tin oxide, iron oxide, titanium oxide, aluminum oxide, an antimony compound, zinc borate and the like, and two or more kinds are used in combination You may Among these, antimony compounds and zinc borate are preferable in terms of more excellent flame retardancy.
Antimony compounds include antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), sodium antimonate and the like. In particular, when a halogen-based flame retardant is used, it is preferable to use antimony trioxide in combination, in view of the synergistic effect with the flame retardant.
When a flame retardant auxiliary is used, it is preferable to include the flame retardant auxiliary together with the flame retardant in the thermoplastic resin.

Although the method of including a flame retardant in the sheet | seat for fiber reinforced plastic molded objects is not limited, The following method can be mentioned. (1) A method of forming a sheet for a fiber-reinforced plastic molded body using a thermoplastic resin containing a flame retardant, (2) A particulate flame retardant is mixed with a slurry of reinforcing fibers and a thermoplastic resin to make a wet paper sheet Method (3) A sheet for a fiber-reinforced plastic molded body is formed using a thermoplastic resin containing a flame retardant, and the sheet is impregnated with a flame retardant slurry, an aqueous solution, an emulsion or the like by dipping or the like, and dried. I can mention the method. In addition, these methods can also be used together.

When the sheet for fiber-reinforced plastic molding contains a flame retardant, it is preferable that the thermoplastic resin contains a flame retardant. The "thermoplastic resin containing a flame retardant" in the present specification refers to a thermoplastic resin blended with a flame retardant to impart flame retardancy. As a flame retardant, the flame retardant mentioned above can be mentioned as a preferable example. In addition, although it is preferable to disperse | distribute a flame retardant uniformly in a thermoplastic resin, what made the flame retardant adhere on the surface can also be used. As a thermoplastic resin which comprises the thermoplastic resin containing a flame retardant, the thing similar to the thermoplastic resin which can be used when a sheet | seat for fiber reinforced plastic molded bodies contains a flame retardant can be listed.

(Binder component)
In the present invention, the binder component is preferably contained in an amount of 0.1 to 10% by mass, and preferably 0.3 to 10% by mass, with respect to the total mass of the sheet for fiber-reinforced plastic moldings. It is more preferable, 0.4 to 9% by mass is further preferable, and 0.5 to 8% by mass is particularly preferable. By setting the content of the binder component within the above range, the strength in the manufacturing process can be increased, and the handling property can be improved. When the amount of the binder component is increased, both the surface strength and the interlayer strength become strong, but conversely, the problem of odor at the time of heat molding tends to occur. However, in the above range, the problem of odor hardly occurs, and a sheet for fiber-reinforced plastic molding can be obtained which does not generate delamination or the like even after repeated cutting steps.

As a binder component, polyester resins such as polyethylene terephthalate and modified polyethylene terephthalate, which are generally used for non-woven fabric manufacture, binder fibers of core-sheath structure combining them, acrylic resin, styrene- (meth) acrylic acid ester co-weight Combined resin, urethane resin, PVA resin, various starches, cellulose derivative, sodium polyacrylate, polyacrylamide, polyvinyl pyrrolidone, acrylamide-acrylic acid ester-methacrylic acid ester copolymer, styrene-maleic anhydride copolymer alkali salt, Isobutylene-maleic anhydride copolymer alkali salt, polyvinyl acetate resin, styrene-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, styrene-butadiene- (meth) Acrylic acid ester copolymer or the like can be used. In addition, polyester resins and polypropylene resins can also be suitably used, and synthetic pulps using resins obtained by modifying these and appropriately adjusting the melting point are preferable because sufficient strength can be obtained even with a small amount.

The binder component preferably contains a copolymer including at least one of a repeating unit derived from a methyl (meth) acrylate-containing monomer and a repeating unit derived from an ethyl (meth) acrylate-containing monomer. Among them, the binder component preferably contains a copolymer including at least one of a repeating unit derived from a methyl methacrylate-containing monomer and a repeating unit derived from an ethyl methacrylate-containing monomer. Also, these monomers may be copolymerized with other monomers such as styrene, vinyl acetate, acrylamide and the like.
In the present invention, "(meth) acrylate" means including both "acrylate" and "methacrylate", and "(meth) acrylic acid" means "acrylic acid" and "methacrylic acid" Is meant to include both.

(Fiber shape)
In the present invention, the thermoplastic resin fiber and the reinforcing fiber are preferably chopped strands cut into a fixed length. The binder fiber is also preferably a chopped strand. By setting it as such a form, various fibers can be uniformly mixed in the sheet | seat for fiber reinforced plastic molded objects. In addition, the cross-sectional shape of the fiber is not limited to a circle, and it is also possible to use an odd-shaped cross section such as an oval.

A method of forming a web by dispersing thermoplastic resin fibers, reinforcing fibers and chopped strands of binder fibers in a solvent and then removing the solvent to produce a sheet for producing a fiber-reinforced plastic molded article of the present invention (wet process) The nonwoven fabric method is adopted.

(Method of manufacturing sheet for fiber reinforced plastic molded body)
The manufacturing process of the sheet | seat for fiber reinforced plastic molded bodies of this invention includes the process of carrying out the wet papermaking of the slurry which mixed the reinforcing fiber and the thermoplastic resin fiber. Here, the thermoplastic resin fiber is a thermoplastic resin fiber having a limit oxygen index of 30 or more, or the sheet for fiber reinforced plastic molded body contains a flame retardant. In addition, the step of wet papermaking includes the step (A) or the step (B).
(A) A step of making a paper at a machine speed of 5 m / min or more using a yen mesh paper machine.
(B) A step of making paper using a Fourdrinier paper machine or a inclined paper machine. When the step of wet papermaking includes (B) a step of making paper using a Fourdrinier paper machine or a slant paper machine, the wire of the Fourdrinier paper machine or the slant paper machine has a jet wire ratio of 0.95 or less To travel.

In the step of wet papermaking, a binder component may be further added to the slurry.

When papermaking is carried out using a cylinder paper machine, the diameter of the circle network of the cylinder paper machine is preferably 50 cm or more. By setting the diameter of the circular mesh of the circular mesh paper machine to the above range, it becomes possible to orient 80% or more of reinforcing fibers parallel to the center plane of the fiber-reinforced plastic molding, thereby making the non-dropping property more It can be enhanced.

When the paper making is performed using a cylinder paper machine, the paper making speed is preferably 3 m / min or more, more preferably 5 m / min or more, and still more preferably 10 m / min or more . By setting the paper-making speed in the above-mentioned range, it is possible to orient 80% or more of reinforcing fibers in parallel with the center plane of the fiber-reinforced plastic molding, and it is possible to further improve the non-dropping property.

When making a paper with a cylinder paper machine, there are a forward flow method and a reverse flow method in the method of introducing the raw material into the paper layer. The forward flow method is a method in which the material is introduced so as to flow in the same direction as the rotation direction of the wire, and the reverse flow method is a method in which the material is introduced such that the material flows in the direction opposite to the rotation direction of the wire. In the present invention, it is easier to orient the reinforcing fibers in one direction when the raw material supply is performed in the reverse flow type.

Further, in the step of wet papermaking, in addition to the cylinder paper machine, a Fourdrinier paper machine or a tilt paper machine may be used. That is, in the process for producing a sheet for fiber-reinforced plastic molding according to the present invention, the step of wet paper making may be a step of making paper using a Fourdrinier paper machine or an inclined paper machine. Here, in the process of making paper using a Fourdrinier paper machine or inclined paper machine, the wire of the Fourdrinier paper machine or inclined paper machine is characterized by traveling such that the jet wire ratio is 0.95 or less. I assume.
The step of wet papermaking is preferably a step of paper making using a Fourdrinier paper machine or an inclined type paper machine, and more preferably a step of paper making using an inclined paper machine.

Here, the jet wire ratio is the ratio of the fiber slurry liquid supply rate to the wire traveling speed, and is represented by the fiber slurry liquid supply speed / wire traveling speed. When the jet wire ratio is larger than 1, the feed rate of the fiber slurry liquid is faster than the traveling speed of the wire, and this case is referred to as "pressed area". In addition, when the jet wire ratio is smaller than 1, the supply speed of the fiber slurry liquid is slower than the traveling speed of the wire, and this case is referred to as "sticking".
In the production method of the present invention, in the case of using a Fourdrinier paper machine or an inclined paper machine, the jet wire ratio may be 0.95 or less. In the production method of the present invention, by setting the jet wire ratio in the above range, the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction in the sheet for fiber reinforced plastic molded body is within the desired range. it can.

When the step of wet paper making is a step of paper making using a tilt paper machine, it is preferable to adjust the suction power of each of a plurality of wet suction boxes provided on the tilt wires of the tilt paper machine as appropriate. Specifically, it is preferable to adjust so that the amount of dehydration of the wet suction box on the downstream side of the inclined wire becomes large. Usually, when the suction force of the wet suction box is made uniform, the amount of fibers in the wet web deposited on the wire is small, and the amount of dewatering on the upstream side of the wire is large, and the amount of fibers deposited on the wire is downstream The amount of dewatering tends to decrease. Therefore, in the present invention, fiber-reinforced plastic molding on the wire is performed by adjusting the suction force on the upstream side to be weaker than the suction force on the downstream side and adjusting the amount of dehydration of the wet suction box on the downstream side of the inclined wire. The body sheet is uniformly dewatered. Thus, by dewatering uniformly, it becomes possible to make the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction in the sheet for fiber reinforced plastic molded body within the desired range.

When paper-making a sheet for a fiber-reinforced plastic molded body, the viscosity at 25 ° C. of the dispersion medium of the slurry (however, according to JIS Z 8803 “Method of measuring viscosity of liquid”) is 1.00 mPa. More than s, it is preferable that it is 4.00 mPa * s or less, and it is more preferable that it is 1.05-2.00 mPa * s.
The term "slurry" as used herein refers to the slurry immediately before the paper making process, and refers to the slurry in the inlet. In addition, when measuring the viscosity of the dispersion medium of the slurry, 500 ml of the slurry at the inlet is collected and measured using a filtrate obtained by filtering the fiber with a 150 mesh metal sieve.

The viscosity of the dispersion medium of the slurry can be adjusted by, for example, adding a polyacrylamide-based adhesive or the like to the inlet. By setting the viscosity of the dispersion medium of the slurry within the above range, the disturbance of the flow of the dispersion in the vicinity of the wire can be suppressed, and a laminar flow can be achieved. Thereby, the fiber orientation parameter (fp) of the thickness direction of the sheet | seat for fiber reinforced plastic molded objects can be carried out in a desired range.

The step of wet papermaking preferably includes the step of internally adding, coating or impregnating the solution containing the binder component or the emulsion containing the binder component to the non-woven fabric sheet and drying by heating. That is, it is preferable that the process of forming the sheet for fiber-reinforced plastic molding includes a process of wet papermaking by a wet nonwoven fabric method and a process of internally adding, coating or impregnating a solution containing a binder component to the nonwoven fabric sheet. Furthermore, after internal addition, application or impregnation, the process of making it heat-dry is included. By providing such a step, it is possible to suppress scattering, fuzzing and falling off of surface fibers of the sheet for fiber-reinforced plastic molding, and a sheet for fiber-reinforced plastic molding having excellent handling properties can be obtained.

After the solution containing the binder component or the emulsion containing the binder component is internally added, coated or impregnated into the sheet for fiber-reinforced plastic molding, it is preferable to rapidly heat the sheet for the fiber-reinforced plastic molding. By providing such a heating step, it is possible to transfer the solution containing the binder component or the emulsion containing the binder component to the surface layer area of the sheet for fiber-reinforced plastic molding. Furthermore, the binder component can be localized in the form of a web.

(Fiber-reinforced plastic molding)
The sheet for fiber-reinforced plastic molding of the present invention can be processed into any shape in accordance with the shape and molding method of the target molded object. Sheets for fiber-reinforced plastic moldings may be laminated singly so as to have a desired thickness and heat / pressure molded with a heat press, or preheated beforehand with an infrared heater etc., and heat / pressure molded with a mold. be able to. As described above, by processing a general sheet for fiber-reinforced plastic molding using a heat and pressure molding method, a fiber-reinforced plastic molding having excellent strength can be obtained.

In the fiber-reinforced plastic molded article of the present invention, the absolute value of the fiber orientation parameter (fp) of the reinforcing fiber in the thickness direction is 0.5 to 1.0. This means that the majority of the reinforcing fibers are present approximately parallel to the center plane of the fiber-reinforced plastic molding. The term "most reinforcing fibers" means 80% or more of the total number of reinforcing fibers. Further, "substantially parallel to the center plane of the fiber-reinforced plastic molding" means that the angle between the center plane of the fiber-reinforced plastic molding and the reinforcing fiber is oriented within ± 20 °.

The thickness of the fiber-reinforced plastic molding is not particularly limited, but is preferably thin in terms of weight reduction when used as a housing of a mobile device or the like. Specifically, it is preferably 0.1 to 50.0 mm, more preferably 0.1 to 10.0 mm or less, and still more preferably 0.4 to 1.0 mm or less. Although the flame retardancy tends to decrease as the thickness decreases, the fiber-reinforced plastic molding of the present invention suppresses the generation of drips during combustion even if the thickness is in the above range, and the flame retardancy is suppressed Is well raised.

The fiber-reinforced plastic molding of the present invention is excellent in non-dropping property. Specifically, a fiber-reinforced plastic molding is cut into a width of 13 mm and a length of 125 mm (the thickness is arbitrary) to form a test piece, the upper end of the test piece is attached to a clamp, and the lower end (side in the width direction) is long at the center It is preferable that the surgical absorbent cotton placed 12 inches below the fiber-reinforced plastic molding does not ignite when a flame of 20 mm in thickness is indirectly flamed for 10 seconds. This means that the molten product of the fiber-reinforced plastic molded body does not drip as a drip when it comes in contact with the fiber-reinforced plastic molded body, or the dripping amount is very small. The above test is a method according to the UL 94 vertical flammability test of the UL standard.

The synergistic average value of the flexural strength in the MD direction and the flexural strength in the CD direction of the fiber-reinforced plastic molding is preferably 200 MPa or more, more preferably 220 MPa or more, still more preferably 250 MPa or more, 280 MPa It is particularly preferable to be the above.

(Molding method of fiber reinforced plastic molding)
The molding method of the sheet for fiber-reinforced plastic molding of the present invention is not particularly limited, and can be selected according to the application of the molded product. As a representative method, press forming is exemplified. In addition, as a method of press molding, among various existing press molding methods, an autoclave method often used when producing a molded article member such as a large aircraft, and a mold press having a relatively simple process. The method is preferably mentioned. The autoclave method is preferred from the viewpoint of obtaining high-quality molded articles with few voids. On the other hand, from the viewpoint of the amount of energy used in facilities and molding processes, simplification of molding jigs and auxiliary materials used, molding pressure and freedom of temperature, gold is used for molding using a metal mold It is preferable to use a mold pressing method, which can be selected according to the application.

A heat and cool method or a stamping method can be employed as the mold pressing method. In the heat and cool method, a sheet for a fiber-reinforced plastic molded body is disposed in advance in a mold, pressed and heated together with mold clamping, and then cooling of the sheet by cooling the mold while the mold is clamped. Method to obtain a molded body. In the stamping molding method, the sheet is previously heated by a heating device such as a far infrared heater, a heating plate, a high temperature oven, a dielectric heating, etc., and the thermoplastic resin is melted and arranged in the molded mold in a melted and softened state. The mold is closed, mold clamping is performed, and then pressure cooling is performed. In addition, when the molding temperature is relatively low, for example, in the case of obtaining a low density molded body, a hot press method can also be adopted.

Molds for molding are roughly classified into two types, one is a closed mold used for casting, injection molding and the like, and the other is an open mold used for press molding and forging. When the sheet for fiber-reinforced plastic molding of the present invention is used, any mold can be used depending on the application. Although an open mold is preferable from the viewpoint of excluding the decomposition gas and mixed air at the time of molding out of the mold, in order to suppress the outflow of the excessive resin, the open part is reduced as much as possible during the molding process. It is also preferable to adopt a shape that suppresses outflow from the mold.

Furthermore, a mold having at least one selected from a punching mechanism and a tapping mechanism can be used for the mold. It is also possible to punch out the formed body continuously after the hot pressing by devising a method such as using a two-stage press mechanism. In addition, depending on the purpose of use of the molded body, it is possible to form projections for reinforcement and processing such as ribs and bosses and screw holes, and to impart a pattern for the purpose of imparting designability.

It is also possible to bond more complex shaped members by outsert molding or insert molding simultaneously with or after molding the sheet for fiber-reinforced plastic molding.

When using a thermoplastic resin as a matrix resin when molding a fiber-reinforced plastic molding from a sheet for fiber-reinforced plastic molding, the resin-containing fiber-reinforced plastic molding sheet is pressure-molded at 150 to 600 ° C. Is preferred. The heating temperature is preferably a temperature at which the thermoplastic resin fibers flow and the reinforcing fibers are not melted.

As a pressure at the time of shape | molding the sheet | seat for resin-containing fiber reinforced plastic molded objects, 0.5-20 Mpa is preferable. Moreover, it is more preferable that it is 0.5-10 Mpa from a viewpoint of suppressing bending of a reinforcement fiber and improving intensity | strength, and it is further more preferable that it is 1-8 Mpa. When using a thermosetting resin, or using a resin that is mixed and impregnated with a curing agent just before impregnating the fiber-reinforced plastic molded body with the resin and is cured at normal temperature, the molding temperature is appropriately selected according to the resin. Can be set. Moreover, when using the said resin, a fiber reinforced plastic molded object can also be shape | molded only by pressurization, without heating.

(Application of fiber reinforced plastic molding)
Examples of applications of the fiber-reinforced plastic molded article according to the present invention include “OA devices, mobile phones, smart phones, mobile information terminals, tablet PCs, mobile electronic devices such as digital video cameras, air conditioners and other housings for home appliances, Reinforcement materials such as ribs to be attached to the housing, civil engineering such as “supports, panels, and reinforcement materials”, parts for building materials, “various frames, bearings for various wheels, various beams, doors, trunk lids, side panels, upper back panels , Front body, underbody, various pillars, various frames, various beams, various supports, outer plates or body parts and reinforcements thereof, separators or diffusion layers for fuel cells, "instrument panels, seat frames, etc. Interior parts or fuel such as gasoline tank, various piping, various valves Parts for automobiles, motorcycles such as exhaust system or intake system parts, engine coolant joint, thermostat base for air conditioner, headlamp support, pedal housing etc. Aircraft parts such as winglet and spoiler Parts for railway vehicles such as seat members for rail vehicles, outer panels, reinforcing materials to be attached to outer panels, ceiling panels, spouts for air conditioners etc., "resin (thermosetting resin, thermoplastic resin) Reinforcing material of a formed product, reinforcing material of a formed product of resin and reinforcing fiber, sheet derived from plants (kraft paper, corrugated board, oil resistant paper, insulating paper, conductive paper, release paper, impregnated paper, glassine paper, cellulose nano It is used suitably for members, such as a reinforcing material of a fiber sheet etc. ".
Thus, the fiber-reinforced plastic molded article of the present invention has high strength and high safety because it has excellent non-dropping properties, and thus housings for electrics and electronic devices, structural parts for automobiles, for aircraft It is preferably used for parts, civil engineering, panels for construction materials, and various other various applications.

The features of the present invention will be more specifically described below with reference to examples and comparative examples. The materials, amounts used, proportions, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below. In addition, in the following, Examples 1, 6, 7, 12, and 14 shall be read as Reference Examples 1, 6, 7, 12, and 14, respectively.

Example 1
(Production of flame retardant-containing polycarbonate fiber)
Polycarbonate resin (component A) (manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Iupilon S-3000 (viscosity average molecular weight: 21,000)), acrylonitrile-styrene copolymer (component B) (technopolymer ( Co., Ltd. trade name: 290FF (melt flow rate (MFR at 50 ° C., 49N load: 50 g / 10 min)) and polycarbonate oligomer (C component) (Mitsubishi Gas Chemical Co., Ltd. trade name: AL071 (Average polymerization degree: 7)) and phosphorus-based flame retardant (D component) (phosphate ester, manufactured by Daihachi Chemical Co., Ltd., trade name: PX-200 Chemical formula: [OC ₆ H ₃ (CH ₃ ) ₂ ] ₂ P (O) OC ₆ H ₄ OP (O) [OC ₆ H ₃ (CH ₃ ) ₂ ] ₂ ) was mixed so as to have a mass ratio of 100 / 5.5 / 12/16. The mixture was melt mixed in a 30 mmφ twin-screw extruder to obtain a pelletized resin composition.
The obtained pellet was melt extruded at a spinning temperature of 300 ° C. using a spinning nozzle (pore diameter: 0.6 mm), and the temperature near the spinning nozzle was cooled to 250 ° C. to obtain a spun filament having a fineness of 100 dtex. The obtained filament was cut into a length of 15 mm with a guillotine cutter to obtain a flame retardant-containing polycarbonate fiber.

As described in Example 1 in Table 1, PAN-based carbon fiber (fiber length 12 mm), the flame retardant-containing polycarbonate fiber (fiber length 15 mm), and polyethylene synthetic pulp as a binder (Mitsui Chemical, SWP AU690) Were weighed so as to be 35 parts by mass of PAN-based carbon fiber, 62 parts by mass of flame retardant-containing polycarbonate resin fiber, and 3 parts by mass of polyethylene synthetic pulp, with respect to the total mass of the sheet for fiber-reinforced plastic molding . Furthermore, the amount of water introduced was 200 times the total mass of the PAN-based carbon fiber and the polycarbonate resin fiber (that is, 0.5% as the fiber slurry concentration).
Add 1 part by mass of "Emanon 3199" (manufactured by Kao Corporation) as a dispersant to this slurry to 100 parts by mass of fiber (total of PAN-based carbon fiber and polycarbonate fiber) and stir, and then disperse the fiber in water The fiber slurry uniformly dispersed in

The fiber slurry was continuously fed back to the cylinder paper machine to form a wet web. Then, it was made to heat-dry at 180 degreeC using the Yankee dryer and hot-air dryer with which the said paper machine was equipped. Thus, a sheet for a fiber-reinforced plastic molded body having a basis weight of 145 g / m ² was obtained. The paper making speed was 15 m / min. In addition, when a fiber slurry is sent to a cylinder paper machine to form a wet web, 0 of anionic polymer polyacrylamide-based thickener “Sumifloc FA 40 HRS (manufactured by MT Aqua Polymer Co., Ltd.)” is formed in the bat of the circle network. As shown in Table 1, the viscosity of the dispersion medium of the slurry (the viscosity at a liquid temperature of 25 ° C. measured by the measurement method defined in JIS Z 8803 “Method of measuring the viscosity of liquid”) is appropriately added It adjusted and paper-made, and obtained the sheet | seat for fiber reinforced plastic molded objects.
The dispersion medium of the slurry is a filtrate obtained by collecting 500 ml of the slurry at the inlet and filtering the fiber with a 150 mesh metal sieve. Further, the absolute value of the fp value of the sheet for fiber-reinforced plastic molding is shown in Table 1.

<Fabrication of a fiber-reinforced plastic molding for measuring the angle of reinforcing fiber and measuring the bending strength>
Nine sheets of each obtained sheet for fiber-reinforced plastic molding are laminated, the press speed is increased at 3.5 cm / sec, the press pressure is raised to 10 ° C., the temperature is raised to 260 ° C., and heating and pressure is applied for 60 seconds, It cooled to 70 degreeC and obtained the fiber reinforced plastic molded object of thickness 1.0mm. The true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molding is indicated by P, and the bulk density (g / cm ³ ) is indicated by Q in Table 1.

<Fabrication of fiber-reinforced plastic molding for combustion test>
The obtained sheet for fiber-reinforced plastic molding is laminated so as to obtain the number of sheets described in Table 1, the press speed is increased at 3.5 cm / sec, the press pressure is raised to 260 ° C. with 10 MPa, 60 After being heated and pressurized for a second, it was cooled to 70 ° C. to obtain a fiber-reinforced plastic molding of the thickness described in Table 1.

Example 2
Example 2 changes the paper machine for forming the wet web of Example 1 to an inclined wire machine, adjusts white water circulation flow rate, anionic high polymer polyacrylamide based thickener, and paper making speed, and jets. The wire ratio was adjusted to 0.90. A sheet for a fiber-reinforced plastic molding was obtained in the same manner as in Example 1 except for the above. In this case, the suction force of the four dewatering boxes provided on the wire of the inclined wire machine was adjusted individually, and the four pieces were adjusted so as to have substantially the same amount of dewatering. Furthermore, the viscosity of the dispersion medium of the slurry (JIS Z 8803 [liquid viscosity measurement method] by appropriately adding an aqueous solution of anionic polymer polyacrylamide-based thickener [Sumifloc (manufactured by MT Aqua Polymer Co., Ltd.) to the inlet] The viscosity at a liquid temperature of 25 ° C. measured by the measurement method specified in “1.” was adjusted as shown in Table 1 and formed into a sheet.
A sheet for fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring an angle of reinforcing fibers and a measurement of bending strength, and a fiber-reinforced plastic molded body for a combustion test are respectively manufactured in the same manner as in Example 1 did.

Example 3
In the same manner as in Example 2 except that the viscosity of the dispersion medium is as shown in Table 1 and the jet wire ratio is adjusted to 0.50, a sheet for a fiber-reinforced plastic molded body, measurement of angle of reinforcing fiber and measurement of bending strength A fiber-reinforced plastic molding for the purpose of producing a fiber-reinforced plastic molding and a fiber-reinforced plastic molding for a combustion test were respectively produced.

Example 4
A sheet for a fiber-reinforced plastic molded body in the same manner as in Example 2 except that the viscosity of the dispersion medium is as shown in Table 1, the fiber length of PAN-based carbon fiber is 25 mm, and the jet wire ratio is adjusted to 0.25. A fiber-reinforced plastic molding for measuring the angle of reinforcing fiber and for measuring the bending strength, and a fiber-reinforced plastic molding for combustion test were respectively produced.

Example 5
Based on the total mass of the sheet for fiber-reinforced plastic molding, 40 parts by mass of PAN-based carbon fiber and 57 parts by mass of flame retardant-containing polycarbonate resin fiber are blended, respectively, and the viscosity of the dispersion medium is as shown in Table 1; In the same manner as in Example 2 except that the ratio was adjusted to 0.25, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of reinforcing fibers and measuring the bending strength, and for burning test Fiber-reinforced plastic moldings were produced respectively.

Example 6
In the same manner as in Example 1 except that the viscosity of the dispersion medium is as shown in Table 1 and the raw material slurry is supplied in a forward flow, the sheet for fiber reinforced plastic molded body, for measuring the angle of reinforcing fiber and for measuring bending strength. A fiber-reinforced plastic molding and a fiber-reinforced plastic molding for a combustion test were produced respectively.

Example 7
A fiber-reinforced fiber was prepared in the same manner as in Example 6, except that the flame retardant polycarbonate fiber was changed to polyetherimide fiber (made by Kuraray, fiber diameter 2.2 dtex × 15 mm) and the viscosity of the dispersion medium was as shown in the table. A sheet for plastic molding, a fiber-reinforced plastic molding for measuring an angle of reinforcing fibers and a measurement of bending strength, and a fiber-reinforced plastic molding for a combustion test were respectively produced.

Example 8
A fiber was prepared in the same manner as Example 2, except that the flame retardant polycarbonate fiber was changed to polyetherimide fiber (made by Kuraray, fiber diameter 2.2 dtex × 15 mm) and the viscosity of the dispersion medium was as shown in Table 1. A sheet for reinforced plastic molded body, a fiber reinforced plastic molded body for measuring the angle of reinforcing fibers and measurement of flexural strength, and a fiber reinforced plastic molded body for burning test were respectively produced.

Example 9
A fiber-reinforced plastic is formed in the same manner as in Example 8, except that flame retardant nylon 6 fiber is used instead of the flame retardant polycarbonate fiber used in Example 8, and the viscosity of the dispersion medium is as shown in Table 1. A body sheet, a fiber-reinforced plastic molding for measuring an angle of reinforcing fibers and a measurement of bending strength, and a fiber-reinforced plastic molding for a combustion test were respectively produced.
As the flame retardant nylon 6 fiber, nylon 6 resin pellet (UNITICA nylon 6 A1030JR manufactured by UNITICA CO., LTD.) Was used in place of the components A, B and C used for the production of the flame retardant polycarbonate resin. It manufactured according to the manufacturing method of the flame-retardant polycarbonate resin fiber of Example 1.

Example 10
A fiber-reinforced fiber was prepared in the same manner as in Example 8, except that a part of the flame retardant polycarbonate fiber of Example 8 was replaced with a polyetherimide fiber to obtain the composition shown in Table 1, and the viscosity of the dispersion medium was as shown in Table 1. A sheet for plastic molding, a fiber-reinforced plastic molding for measuring an angle of reinforcing fibers and a measurement of bending strength, and a fiber-reinforced plastic molding for a combustion test were respectively produced.

Example 11
A part of the polyetherimide fiber of Example 8 was changed to a polycarbonate fiber (manufactured by Daiwabo Polytech, 30 μφ × 15 mm) to obtain the composition shown in Table 1, and the viscosity of the dispersion medium was as shown in Table 1 In the same manner as in No. 8, a sheet for fiber-reinforced plastic molding, a fiber-reinforced plastic molding for measuring the angle of reinforcing fibers and measurement of flexural strength, and a fiber-reinforced plastic molding for combustion test were respectively produced.

Example 12
A sheet for a fiber-reinforced plastic molded body, a reinforcing sheet in the same manner as in Example 7 except that carbon fibers in Example 7 are changed to glass fibers to be a composition shown in Table 1, and the viscosity of the dispersion medium is as shown in Table 1. A fiber-reinforced plastic molding for measurement of fiber angle and flexural strength, and a fiber-reinforced plastic molding for combustion test were respectively produced.

Example 13
A sheet for a fiber-reinforced plastic molded body, a reinforcing sheet in the same manner as in Example 8 except that carbon fibers in Example 8 are changed to glass fibers to obtain a composition shown in Table 1, and the viscosity of the dispersion medium is as shown in Table 1. A fiber-reinforced plastic molded body for measuring an angle of a fiber and a flexural strength, and a fiber-reinforced plastic molded body for a combustion test were respectively produced.

Example 14
For Example 2, the viscosity of the dispersion medium was adjusted as shown in Table 1 by reducing the amount of addition of the anionic high molecular weight polyacrylamide-based thickener, and the suction powers of the four dewatering boxes provided in the inclined wire were all the same. And a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring an angle of reinforcing fiber and a measurement of bending strength in the same manner as in Example 2 except that the jet wire ratio is adjusted to 0.90. And fiber-reinforced plastic moldings for the combustion test were prepared.

Example 15
(Preparation of flame retardant-containing polycarbonate resin powder)
The flame retardant-containing polycarbonate resin pellet (Teijin LN-2520A) was freeze-crushed to obtain a flame retardant-containing polycarbonate resin powder having an average primary particle diameter of 800 μm.
As described in Example 15 in Table 2, Example 2 except that the flame retardant-containing polycarbonate fiber was changed to the flame retardant-containing polycarbonate resin powder obtained above, and the jet wire ratio was adjusted to 0.88. In the same manner as in the above, a sheet for fiber-reinforced plastic molding, a fiber-reinforced plastic molding for measuring the angle of reinforcing fibers and measurement of flexural strength, and a fiber-reinforced plastic molding for combustion test were respectively produced.

Example 16
In the same manner as in Example 15 except that the jet wire ratio was adjusted to 0.51 and the viscosity of the dispersion medium was as shown in the table, the sheet for fiber reinforced plastic molded body, for measuring the angle of reinforcing fiber and bending strength A fiber reinforced plastic molded body for measurement and a fiber reinforced plastic molded body for combustion test were respectively produced.

Comparative Example 1
As described in Comparative Example 1 in Table 3, in the same manner as in Example 2 except that the viscosity of the dispersion medium was adjusted and the jet wire ratio was adjusted to 1.3, Fiber reinforced plastic moldings for angle measurement and measurement of bending strength and fiber reinforced plastic moldings for combustion test were respectively produced.

Comparative Example 2
In the same manner as in Example 2 except that the viscosity of the dispersion medium is as shown in Table 3 and the jet wire ratio is adjusted to 3.5, a sheet for a fiber-reinforced plastic molded body, measurement of angle of reinforcing fiber and measurement of bending strength A fiber-reinforced plastic molding for the purpose of producing a fiber-reinforced plastic molding and a fiber-reinforced plastic molding for a combustion test were respectively produced.

Comparative Example 3
Comparative Example 1 and Comparative Example 1 except that the flame retardant-containing polycarbonate resin fiber of Comparative Example 1 was changed to polyetherimide fiber (made by Kuraray, fiber diameter 2.2 dtex × 15 mm) and the viscosity of the dispersion medium was as shown in Table 3. Similarly, a sheet for fiber-reinforced plastic molding, a fiber-reinforced plastic molding for measuring an angle of reinforcing fibers and a measurement of bending strength, and a fiber-reinforced plastic molding for a combustion test were respectively produced.

Comparative Example 4
The carbon fiber of Comparative Example 2 was changed to glass fiber, and the flame retardant-containing polycarbonate resin fiber was changed to polyetherimide fiber to obtain the composition shown in Table 3, and the viscosity of the dispersion medium was as shown in Table 3 In the same manner as in Example 2, a sheet for a fiber-reinforced plastic molding, a fiber-reinforced plastic molding for measuring the angle of reinforcing fibers and measurement of flexural strength, and a fiber-reinforced plastic molding for a combustion test were respectively produced.

(Evaluation)
<Measurement of fiber orientation parameter (fp value) of reinforcing fiber in thickness direction>
The sheet for fiber-reinforced plastic molding obtained in Examples and Comparative Examples is cut into a width of 5 mm and a length of 10 mm, and an ultraviolet curing type embedding epoxy resin (ALONIX LCA D-800, manufactured by JEOL Ltd.) A dropper was dropped and impregnated so as to cover the entire surface of the test piece, and the coating was cured by irradiation with ultraviolet light.
Then, a test piece having a width of 0.4 mm and a length of 10 mm was cut out from the test piece for observation of cross section, using Slice Master HS-1 manufactured by JASCO Corporation. In addition, the cutting direction was made into the BB 'direction in FIG.1 (b). The BB ′ direction is a direction parallel to the reference line in the plane direction determined by the method described later.
The cross section in the thickness direction of the obtained test piece was enlarged by 300 times with a microscope manufactured by Ens, Inc., and the reinforcing fiber was observed by transmitted light. Here, a continuous 1.5 mm ² measurement area of the above cross section was observed. In addition, observation was performed by focusing on a portion having a depth of 10 μm or more from each of the observation surface of the test piece and the opposite surface thereof. Then, for all the reinforcing fibers (the number of fibers is n) visible in the observation image and present in the measurement area, the angles θi (i = 1 to n) with respect to the reference line set by the method described later It was measured. The orientation angle θi was an angle in the clockwise direction measured with respect to the reference line, and was an angle of 0 ° or more and less than 180 °. And the fiber orientation parameter of the thickness direction was computed from the angle (theta) i of the fiber with respect to the set reference line using following formula (1).
fp = 2 × Σ (cos ² θ _i / n) −1 Formula (1)

The reference line was determined by the following method. When determining the reference line, first, a temporary reference line p was selected, and the angles of all n visible reinforcing fibers present in the measurement area were measured. In this case, the angles of the temporary reference line p and the fibers are represented by α (p) _i (i = 1 to n).
The fiber orientation parameter (fp (p)) of the reinforcing fiber at the time of using the temporary reference line p was calculated using the following equation.
fp (p) = 2 × Σ (cos ² α (p) _i / n) −1
(I = 1, 2, 3, ..., n)
Next, the temporary reference line p is rotated by ± 1 ° to ± 90 ° and the temporary reference line (p _{+ z} , p _−z (z = 1 to 90)) is taken, and the temporary reference line p _{+ z} And the angle of the temporary reference line p- _z and n fibers was calculated. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to n).
The rotated temporary reference line (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber were calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / n) -1
(I = 1, 2, 3, ..., n)
Thus, the temporary reference line set when the maximum value was obtained among the absolute values of the obtained fp (p) value and fp (p ± _z ) value was used as a reference line.

<Measurement of fiber orientation parameter (fp value) of reinforcing fiber in plane direction>
The sheet for a fiber-reinforced plastic molding obtained in Examples and Comparative Examples is cut out so as to have a width of 3 cm × length 3 cm, this test piece is sandwiched by slide glass, and one surface of the test piece is observed with an optical microscope. I observed it. As a light microscope, a microscope made by Keyence Corporation was used, and magnified 300 times, and the reinforcing fibers were observed with reflected light. Here, the continuous 2.0 mm ² measurement area of the one surface was observed. Then, with respect to all the reinforcing fibers (the number of fibers is m) which can be visually recognized in the observation image, which are present in this measurement region, the angles θi (i = 1 to m) with respect to the reference line set by the method described later It was measured. The orientation angle θi was an angle in the clockwise direction measured with respect to the reference line, and was an angle of 0 ° or more and less than 180 °. And the fiber orientation parameter of the thickness direction was computed from the angle (theta) i of the fiber with respect to the set reference line using following formula (2).
fp = 2 × Σ (cos ² θ _i / m) −1 Formula (2)
And it measured similarly about the opposite surface, calculated | required the average value of one surface and the opposite surface, and made this the fiber orientation parameter (fp) of the planar direction. In addition, the measurement area on one side and the measurement area on the opposite side were made to overlap in plan view. In addition, in each observation of one surface and the opposite surface, the observation was performed by focusing on a portion having a depth of 10 μm or more from each of the one surface and the opposite surface.

The reference line was determined by the following method. In determining the reference line, first, a temporary reference line p was selected, and the angles of m visible reinforcing fibers present in the measurement area were measured. In this case, the temporary reference line p and the angle of each fiber were represented by α (p) _i (i = 1 to m).
The fiber orientation parameter (fp (p)) at the time of using the temporary reference line p was calculated using the following equation.
fp (p) = 2 ×× (cos ² α (p) _i / m) −1
(I = 1, 2, 3 ... m)
Next, the temporary reference line p is rotated by ± 1 ° to ± 90 ° and the temporary reference line (p _{+ z} , p _−z (z = 1 to 90)) is taken, and the temporary reference line p _{+ z} And the angle of temporary reference line p- _z and m fibers was calculated. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to m).
The rotated temporary reference line (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber were calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / m) -1
(I = 1, 2, 3 ... m)
Thus, the temporary reference line set when the maximum value was obtained among the absolute values of the obtained fp (p) value and fp (p ± _z ) value was used as a reference line.

<Measurement of angle between reinforcing fiber and fiber reinforced plastic molding>
The angle between the reinforcing fiber and the center plane of the fiber-reinforced plastic molding was measured as follows. First, the cross section of MD direction was cut out about the fiber reinforced plastic molded object for angle measurement of the reinforced fiber obtained by the Example and the comparative example. The reinforcing fiber of this cross section is photographed with a three-dimensional measurement X-ray CT apparatus (manufactured by Yamato Scientific Co., Ltd .: trade name “TDM1000-IS / SP”), and converted to three-dimensional volume rendering software (manufactured by NVS: “VG-Studio MAX”) The image of the cross section was obtained. Then, for the cross-sectional image obtained, ten 10 μm line creases are arbitrarily drawn in the Z-axis direction, and as shown by the white line in FIG. 4 for all the fibers visible in contact with the line, reinforced fibers and fiber reinforced plastic The angle formed with the center plane of the molded body was measured. Specifically, a line parallel to the center plane of the fiber-reinforced plastic molding is represented by a line H (dotted line), and the angle between the line H and the reinforcing fiber was measured. The number of fibers measured was about 100 to 130. And the ratio of the fiber number which the angle which makes with the center plane of a fiber reinforced plastic molded object with respect to the total number of the reinforced fiber measured is within ± 20 degrees is shown in Tables 1-3.

<Measurement of bending strength>
The fiber-reinforced plastic molded product for flexural strength measurement obtained in Examples and Comparative Examples is subjected to fiber orientation direction (machine direction, hereinafter referred to as MD) and fiber orientation according to a bending test method of JIS K 7074 carbon fiber reinforced plastic And the perpendicular direction (cross direction, hereinafter referred to as CD), and the intensity and the intensity ratio between the MD direction and the CD direction are shown in Tables 1 to 3.
Geometrical mean value of bending strength = ((FMD x FCD)
Here, FMD represents bending strength in the MD direction, and FCD represents bending strength in the CD direction.

<Evaluation method of flammability>
The test pieces for the flammability test obtained in Examples and Comparative Examples were cut out into a width of 13 mm and a length of 125 mm. Attach the upper end of this test piece to the clamp, indirectly flame a flame with a length of 20 mm at the center of the lower end (side in the width direction) for 10 seconds, then separate the flame from the test piece and immediately reheat it for 10 seconds after digestion. After removing the flame, the presence or absence of a drip was observed. In this case, surgical cotton wool was placed 12 inches below the fiber-reinforced plastic molding, and the presence or absence of ignition was recorded. And the state of the dripping thing from a test piece and absorbent cotton was observed, and the flammability was evaluated as follows. The flame with a length of 20 mm used for the evaluation is a blue flame with a length of 20 mm specified in the UL94 vertical flammability test of the UL standard.
○: no dripping occurs.
Δ: Drops are produced but in a very small amount, and no ignition of cotton occurs.
X: Ignition of cotton occurs by dripping matter.

As can be seen from Tables 1 to 3, in Examples 1 to 15, the absolute value of the fp value in the thickness direction in the sheet for a fiber-reinforced plastic molded body is within the predetermined range, It turns out that it is hard to occur. In Examples 1 to 15, the angle between the reinforcing fiber and the center plane of the fiber-reinforced plastic molded article is within ± 20 ° over 80%, making it difficult for dripping substances to be generated during the flammability test. Know that On the other hand, in Comparative Examples 1 to 4, the fp value in the thickness direction of the sheet for a fiber-reinforced plastic molded body was within the predetermined range, and dripping of the melted thermoplastic resin was observed at the time of the flammability test. Further, in Comparative Examples 1 to 4, the angle between the reinforcing fiber and the center plane of the fiber-reinforced plastic molding is less than 80% within ± 20 °, and a drop of the thermoplastic resin melted in the flammability test is It was observed.

In FIG. 4, the cross section of the fiber-reinforced plastic molding of Example 6 is photographed with a three-dimensional measurement X-ray CT apparatus (manufactured by Yamato Scientific Co., Ltd .: trade name “TDM1000-IS / SP”), and three-dimensional volume rendering software (NVS) Manufactured: “VG-Studio MAX”) shows the orientation of fibers confirmed by the image obtained. The imaging conditions in the three-dimensional measurement X-ray CT apparatus were: voltage: 40 kV, tube current: 22 μA, number of pixels: 512 × 512 pixels, visual field size: 2.0 mmφ × 2.0 mmh.

According to the present invention, it is possible to obtain a sheet for a fiber-reinforced plastic molded body capable of forming a fiber-reinforced plastic molded body in which the generation of drips is suppressed at the time of combustion.

5 Sheet 20 for fiber-reinforced plastic molding 20 Reinforcing fiber 20 'Reinforcing fiber 25 Thermoplastic resin 40 Embedding epoxy resin 45 Test specimen for cross-sectional observation 50 Flame 60 Drop of melted thermoplastic resin 100 Fiber-reinforced plastic molding 101 Conventional Fiber-reinforced plastic molding P Reference line P 'Line parallel to reference line (auxiliary line)
A line representing the angle of the reinforcing fiber to the Q reference line A line representing the angle of the reinforcing fiber to the reference line

Claims (2)

Wet-making a slurry of a mixture of reinforcing fibers and thermoplastic resin fibers;
The thermoplastic resin fiber is a thermoplastic resin fiber having a limit oxygen index of 30 or more, or the sheet for fiber reinforced plastic molded body contains a flame retardant,
The wet paper making process is a paper making process using a Fourdrinier paper machine or an inclined paper machine,
The wire of the Fourdrinier paper machine or the inclined paper machine is a step of traveling so that the jet wire ratio is 0.95 or less ,
The viscosity at 25 degrees C of the dispersion medium of the said slurry is a manufacturing method of the sheet | seat for fiber reinforced plastic molded bodies which is 1.00 mPa or more and 4.00 mPa or less .   The method for producing a sheet for fiber-reinforced plastic molding according to claim 1, wherein the step of wet-type paper making is a step of making paper using an inclined paper machine.