TWI659051B - Fiber-reinforced plastic molded body sheet and method for producing the same, and fiber-reinforced plastic molded body - Google Patents

Abstract

An object of the present invention is to provide a sheet for a fiber-reinforced plastic molded body capable of suppressing the occurrence of dripping matter during combustion during molding. The present invention relates to a sheet for a fiber-reinforced plastic molded body, which contains reinforcing fibers and a thermoplastic resin, and is characterized in that the thermoplastic resin is a thermoplastic resin having an oxygen limiting index of 30 or more, or the sheet for a fiber-reinforced plastic molded body contains a flame retardant, The absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded body is 0.5 to 1.0.

Description

Sheet for fiber-reinforced plastic molded body, manufacturing method thereof, and fiber-reinforced plastic molded body

The present invention relates to a sheet for a fiber-reinforced plastic molded body. Specifically, the present invention relates to a sheet for a fiber-reinforced plastic molded body in which the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction is within a specific range.

A fiber-reinforced plastic molded body formed by heating and pressing a nonwoven fabric containing reinforcing fibers such as carbon fibers or glass fibers has been used in various fields such as sports, leisure products, and aircraft materials. In these fiber-reinforced plastic molded bodies, resins that serve as a matrix are often thermosetting resins such as epoxy resins, unsaturated polyester resins, or phenol resins. However, when using a thermosetting resin, there is a disadvantage that the non-woven fabric before the press molding process in which the thermosetting resin and the reinforcing fibers have been mixed must be stored under refrigeration and cannot be stored for a long time.

Therefore, in recent years, a fiber-reinforced nonwoven fabric using a thermoplastic resin as a matrix resin and containing reinforcing fibers is being developed. This fiber-reinforced nonwoven fabric using a thermoplastic resin as a matrix resin has the advantages of easy storage management and long-term storage. point. Moreover, a nonwoven fabric containing a thermoplastic resin has advantages compared with a nonwoven fabric containing a thermosetting resin in that it is easy to be molded and processed, and a molded product can be molded by applying heat and pressure.

Conventionally, among thermoplastic resins, thermoplastic resins that are inferior to thermosetting resins in terms of chemical resistance or strength are the mainstream. However, in recent years, thermoplastic resins excellent in heat resistance and chemical resistance have been actively developed, and the disadvantages described above, which have been considered to be common knowledge with respect to thermoplastic resins, have been unusually significantly improved. Such thermoplastic resin is a so-called "engineering plastic" resin, and examples thereof include polycarbonate (PC), polyphenylene sulfide (PPS), and polyether ether. (ketone, PEEK), polyamide imide (PAI), polyetherimide (PEI), and the like (for example, Non-Patent Document 1).

In addition, the fiber-reinforced plastic molded body is used not only for the aircraft or the automobile, but also for building materials, electrical products, and the like. Therefore, it is also required to prevent a fire from causing a fire. Therefore, a fiber-reinforced plastic molded article is required to have higher flame retardancy. For example, Patent Documents 1 and 2 propose to improve the flame retardancy of a fiber-reinforced plastic molded article by including a flame-retardant in the fiber-reinforced plastic molded article. In addition, Patent Document 2 examines dripping of polycarbonate during combustion by adding glass fibers.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-226697

[Patent Document 2] Japanese Patent Publication No. 60-16473

[Non-patent literature]

[Non-Patent Document 1] "2007 Annual Survey Report on the Application of Thermoplastic Resin Composites to the Machinery Industry", the next-generation metal. Composite Materials Research and Development Association, Japan National Federation of Machinery Industries, March 2008

As described above, by including a flame retardant in the fiber-reinforced plastic molded article, flame retardancy can be improved to some extent. However, in the fiber-reinforced plastic molded article disclosed in Patent Document 1, a molten resin or the like drips during combustion, and such a dripping substance becomes an igniter for other materials, which is a problem. In addition, according to the study by the present inventors, it is found that the fiber-reinforced plastic molded article disclosed in Patent Document 2 has not sufficiently suppressed dripping of a thermoplastic resin or the like.

Therefore, the present inventors have conducted researches in order to solve such a problem of the prior art, and provide a sheet for a fiber-reinforced plastic molded body that suppresses the formation of a fiber-reinforced plastic molded body during dripping and burning.

The present inventors conducted diligent research in order to solve the above problems, and as a result, found that in a sheet for a fiber-reinforced plastic molded article containing reinforcing fibers and a thermoplastic resin, the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction is set. Within a specific range, the drip resistance of the fiber-reinforced plastic molded article can be improved.

Specifically, the present invention has the following configuration.

[1] A sheet for a fiber-reinforced plastic molded body, which contains reinforcing fibers and heat A plastic resin, characterized in that the thermoplastic resin is a thermoplastic resin having a limiting oxygen index of 30 or more, or the sheet for a fiber-reinforced plastic molded body contains a flame retardant, and the thickness direction of the sheet for the fiber-reinforced plastic molded body The absolute value of the fiber orientation parameter (fp) of the reinforced fiber is 0.5 to 1.0.

[2] The sheet for a fiber-reinforced plastic molded article according to [1], wherein when the sheet for a fiber-reinforced plastic molded article contains a flame retardant, the thermoplastic resin is a thermoplastic resin containing a flame retardant.

[3] The sheet for a fiber-reinforced plastic molded article according to [1] or [2], wherein the thermoplastic resin is a thermoplastic resin fiber.

[4] The sheet for a fiber-reinforced plastic molded article according to any one of [1] to [3], which further contains a binder component and contains a total mass relative to the sheet for a fiber-reinforced plastic molded article. The adhesive component is 0.1% to 10% by mass.

[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] The sheet for a fiber-reinforced plastic molded article according to any one of [1] to [5], wherein when the sheet for a fiber-reinforced plastic molded article contains a flame retardant, the thermoplastic resin is polycarbonate or polyfluorene amine.

[7] The sheet for a fiber-reinforced plastic molded article according to any one of [1] to [6], wherein the thermoplastic resin having an oxygen limiting index of 30 or more is polyetherimide.

[8] A fiber-reinforced plastic molded body obtained by adding the sheet for a fiber-reinforced plastic molded body according to any one of [1] to [7] at a temperature higher than a melting point of a thermoplastic resin or a temperature higher than a glass transition temperature. It is formed by pressure heating molding, and is characterized by: fiber reinforced plastic The absolute value of the fiber alignment parameter (fp) of the reinforcing fibers in the thickness direction in the green compact is 0.5 to 1.0.

[9] The fiber-reinforced plastic molded article according to [8], which has a thickness of 0.4 mm to 1.0 mm.

[10] The fiber-reinforced plastic molded article according to [8] or [9], wherein the geometric mean of the bending strength is 200 MPa or more.

[11] The fiber-reinforced plastic molded body according to any one of [8] to [10], wherein the fiber-reinforced plastic molded body is formed by heating and pressing at a temperature of 150 ° C to 600 ° C.

[12] A method for manufacturing a sheet for a fiber-reinforced plastic molded article, comprising the step of wet-making a slurry made of a mixture of reinforcing fibers and thermoplastic resin fibers, and the thermoplastic resin fibers are oxygen-limited A thermoplastic resin fiber with an index of 30 or more, or a sheet for a fiber-reinforced plastic molded body contains a flame retardant, and the step of performing wet papermaking is (A) using a cylinder paper machine to perform papermaking at a speed of 5m / min or more Step, or (B) a step of making paper using a Fourdrinier paper machine or an inclined paper machine, when the step of performing wet papermaking includes (B) a step of making a paper using a Fourdrinier paper machine or inclined paper machine, the Fourdrinier paper machine The wire of the papermaking machine or the inclined papermaking machine moves so that the jet / wire ratio becomes 0.95 or less.

[13] The method for producing a sheet for a fiber-reinforced plastic molded body according to [12], wherein the viscosity of the dispersion medium of the slurry at 25 ° C. exceeds 1.00 mPa and is 4.00 mPa or more. under.

[14] The method for producing a sheet for a fiber-reinforced plastic molded article according to [12] or [13], wherein the step of performing wet papermaking is a step of performing papermaking using an inclined papermaking machine.

According to the present invention, it is possible to obtain a sheet for a fiber-reinforced plastic molded body capable of molding a fiber-reinforced plastic molded body that suppresses generation of drips during combustion. In the fiber-reinforced plastic molded body molded from the sheet for a fiber-reinforced plastic molded body of the present invention, the non-dripping property is sufficiently improved, and thereby the flame retardancy is improved. Therefore, the fiber-reinforced plastic molded product of the present invention is preferably used in airplanes, automobiles, building materials, and electrical products that require functions such as flame retardance.

5‧‧‧Fiber-reinforced plastic molded body sheet

20‧‧‧ reinforced fiber

20'‧‧‧ Reinforced Fiber

25‧‧‧thermoplastic resin

40‧‧‧Epoxy for embedding

45‧‧‧ Test piece for section observation

50‧‧‧ flame

60‧‧‧ droplets of molten thermoplastic resin

100‧‧‧ fiber reinforced plastic molded body

101‧‧‧ Existing fiber reinforced plastic moldings

H‧‧‧line

P‧‧‧Baseline

P'‧‧‧ line parallel to the reference line (auxiliary line)

Q‧‧‧ Alignment line of reinforced fiber

R‧‧‧ Alignment line of reinforced fiber

V‧‧‧ line

θ ₁ ‧‧‧alignment angle

θ ₂ ‧‧‧Alignment angle

FIGS. 1 (a) and 1 (b) are image diagrams of a test piece for cross-section observation for measuring fiber alignment parameters of a sheet for a fiber-reinforced plastic molded body of the present invention.

FIGS. 2 (a) and 2 (b) are image diagrams showing the orientation of a part of the reinforcing fibers in a conventional fiber-reinforced plastic molded body, and a state in which the thermoplastic resin starts to melt when the conventional fiber-reinforced plastic molded body is ignited.

FIGS. 3 (a) and 3 (b) are image diagrams showing the orientation of reinforcing fibers in the fiber-reinforced plastic molded article of the present invention, and the case where the thermoplastic resin starts to melt when the fiber-reinforced plastic molded article of the present invention is ignited.

Fig. 4 is a graph showing the distribution of reinforcing fibers in a fiber-reinforced plastic molded article of the present invention. State photos.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be performed based on a representative embodiment or a specific example, but the present invention is not limited to such an embodiment. In addition, the numerical range indicated by "~" in this specification means the range including the numerical value described before and after "~" as a lower limit and an upper limit.

(Fiber-reinforced plastic molded body sheet)

The present invention relates to a sheet for a fiber-reinforced plastic molded article containing reinforcing fibers and a thermoplastic resin. In the present invention, the thermoplastic resin is a thermoplastic resin having an oxygen limiting index of 30 or more, or a sheet for a fiber-reinforced plastic molded body contains a flame retardant. The absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded article of the present invention is 0.5 to 1.0.

In the present specification, the fiber alignment parameter (fp) of the reinforcing fibers is a parameter indicating the alignment state of the reinforcing fibers in the sheet for a fiber-reinforced plastic molded body. The fiber orientation parameter (fp) is a parameter representing the distribution of the fiber orientation with a value of -1.0 to 1.0. When fp = -1.0 and fp = 1.0, the reinforcing fibers are aligned in one direction. When fp = 0.0, the reinforcing fibers are completely random.地 Configuration.

In the present invention, the absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded product may be 0.5 to 1.0. The absolute value of the fiber alignment 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 even more preferably 0.8 to 1.0. By reinforcing fibers in the thickness direction The absolute value of the fiber orientation parameter (fp) is set within the above range, so that the orientation of the reinforcing fibers in the thickness direction can be fixed, and the fiber reinforced plastic molded body molded from the sheet of the fiber-reinforced plastic molded body can be improved. Dripping sex.

The fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded body can be controlled by, for example, appropriately selecting a method for producing the sheet for a fiber-reinforced plastic molded body.

When the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded body is measured, the sheet for the fiber-reinforced plastic molded body is impregnated with an epoxy resin for embedding which is usually used in observation with an electron microscope And the like to prepare a test piece for cross-section observation. Here, the epoxy resin for impregnation and embedding is to prevent the orientation direction of the fiber from being changed by the shearing force at the time of cutting when the section is cut out later. As the embedding resin, an epoxy resin, a styrene resin, or the like is preferred, which has sufficient strength to resist shearing forces. In the present invention, the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction is measured by using an epoxy resin in the present invention. Examples of the embedding resin include Aronix LCA D-800 manufactured by Japan Electron Optics Laboratory Co., Ltd. In addition, a thermosetting resin or a resin that generates heat during curing may reduce the adhesion between the reinforcing fibers of the binder in the sheet for fiber-reinforced plastic moldings due to heat during curing, and the angle of the reinforcing fibers may change. Therefore, a resin that does not become a heat source when cured, such as a photocurable epoxy resin such as ultraviolet rays, is preferred.

As a method for embedding the resin, a method generally used for observation with an electron microscope or observation with an optical microscope can be adopted. Specifically, a fiber-reinforced plastic molded body The sheet was cut into a width of 5 mm and a length of 10 mm, and the embedding epoxy resin was dropped until it covered at least the entire surface of the test piece to impregnate and cure. The dropping of the embedding epoxy resin can be performed using, for example, a syringe.

1 (a) and 1 (b) are conceptual diagrams of a test piece for cross-sectional observation obtained by impregnating a sheet for a fiber-reinforced plastic molded body with an ultraviolet curing epoxy resin for embedding. As shown in FIG. 1 (a), the test piece 45 for cross-sectional observation includes a reinforcing fiber 20 and a thermoplastic resin 25, and an embedding epoxy resin 40 constituting the fiber-reinforced plastic molded sheet 5. In the test piece 45 for cross-section observation, the positional relationship and shape of the reinforcing fibers 20 and the thermoplastic resin 25 are the same as those in the state of the fiber-reinforced plastic molded sheet 5. That is, in the test piece 45 for cross-sectional observation, the embedding epoxy resin 40 exists so that the positional relationship and shape of the reinforcing fiber 20 and the thermoplastic resin 25 may be maintained.

In addition, in FIG. 1 (a), the thermoplastic resin 25 is shown in a fiber shape, but it may not be a fiber shape in practice, and may be a particle shape or the like as described later. When the thermoplastic resin 25 has a fiber shape as shown in FIG. 1 (a), the thermoplastic resin 25 has the same shape as the reinforcing fiber 20, and even looks indistinguishable. However, when the alignment state of the reinforcing fibers is observed, only the alignment of the reinforcing fibers can be observed by using differences in fiber diameters, differences in fiber colors, or element mapping.

When observing the fiber alignment in the thickness direction, a test piece having a width of 0.3 mm to 0.6 mm was cut out from the test piece for cross-section observation, and a cross section in the thickness direction of the obtained test piece was observed with an optical microscope. As a cutting method, a method of cutting vertically with a thin and sharp knife such as a safety razor and a surgical knife can be adopted. However, it is difficult to obtain a vertical profile by manual operation, so it can also be used to cut out Fourier A film slicer such as a Fourier transform infrared spectroscopy (FT-IR) measurement slice or an ion slicer for cutting out an electron microscope observation slice. In addition, as the film slicer, the Slice Master HS-1 manufactured by JASCO Corporation can be exemplified, and as the ion slicer, the EM-09100IS manufactured by Japan Electronics Co., Ltd. can be exemplified. Here, the cut-out direction of the test piece is a direction parallel to the reference line of the planar direction determined by a method described later. An optical microscope uses a microscope manufactured by Keyence Corporation to magnify a monofilament to observe the fibers. When the reinforcing fibers are not transparent fibers (for example, carbon fibers, etc.), the reinforcing fibers can be observed by transmitted light. In this embodiment, for example, the magnification can be selected from 300 times, 600 times, and 800 times. In addition, the observation of the reinforcing fiber was performed by focusing on a portion having a depth of 10 μm or more from the observation surface and the opposite surface of the test piece. The test piece may be cut out using a microtome.

In the present invention, by cutting out a cross section in the thickness direction after embedding with epoxy resin, it is possible to prevent the angle of the fiber from being changed by the shearing force during cutting.

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

In addition, when a transparent reinforcing fiber such as glass fiber is used, the interface between the reinforcing fiber and the resin may not be clearly distinguished even when observed with an optical microscope as described above. At this time, it is embedded with epoxy resin as described above. After the sheet for a fiber-reinforced plastic molded body is cut out so that the cross-section of the test piece for cross-section observation is exposed, element mapping is performed to observe the alignment of the reinforcing fibers. At this time, the elements to be mapped are elements contained only in the reinforcing fibers and not contained in the thermoplastic resin and the epoxy resin. For example, in glass fibers, Si or Ca elements can be mapped using an electron microscope equipped with an Energy Dispersive X-Ray Spectroscopy (EDS / EDX) device, thereby measuring the fiber orientation. An example of such a device is a desktop scanning electron microscope "PRO X" manufactured by Phenom-World company.

The orientation direction of the reinforcing fibers is the major axis direction of the reinforcing fibers. In addition, in the cross section in the thickness direction, reinforcing fibers may be recognized in an oval shape. When the reinforcing fiber is recognized in an oval shape, the major axis direction of the oval is the orientation direction of the fiber. The orientation angle θ _i 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, a cross section in the thickness direction of the test piece is observed with an optical microscope or the like under the above conditions, and an arbitrary selected continuous 1.5 mm ² measurement area in the cross section is observed. The alignment angle θ _i of all discernable fibers (the number of fibers is set to n) was measured. The alignment angle θ _i is an angle measured clockwise with respect to a reference line, and is set to an angle of 0 ° or more and less than 180 °.

The fiber alignment parameter (fp, hereinafter also referred to as fp value) in the thickness direction can be calculated from the alignment angle θ _i measured by the above method using the following formula (1).

fp = 2 × Σ (cos ² θ _i / n) -1 Equation (1)

Here, θ _i is the alignment 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.

When setting the reference line, first, the hypothetical reference line p is selected, and the angles of all the n reinforcing fibers recognizable in the measurement area are measured. At this time, it is assumed that the angle between the reference line p and each fiber is expressed by α (p) _i (i = 1 to n).

The fiber orientation parameter (fp (p)) when the reference line p is assumed can be calculated using the following formula.

fp (p) = 2 × Σ (cos ² α (p) _i / n) -1

(i = 1, 2, 3, ..., n)

Next, take the hypothetical baseline (p _{+ z} , p _-z (z = 1 ~ 90)) obtained by rotating the hypothetical baseline p in units of ± 1 ° until it becomes ± 90 °, and calculate the hypothetical baseline p _{+ z} and The angle of n fibers and the angle of the assumed reference line p _-z to the n fibers. The angle at this time is expressed by α (p _{+ z} ) _i and α (p _-z ) _i (i = 1 ~ n).

The assumed reference lines (p _{+ z} , p _-z (z = 1 to 90)) obtained by the rotation, and the fiber alignment 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)

In this way, the assumed reference line set when the maximum value is obtained among the obtained absolute values of fp (p) value and fp (p _{± z} ) value may be used as the reference line P. The fiber alignment parameter calculated based on the reference line P thus determined may be the fiber alignment parameter (fp) in the thickness direction.

Fig. 1 (b) is a conceptual cross-sectional view of the test piece 45 for cross-section observation shown in Fig. 1 (a), which is cut out in the BB 'direction and the thickness direction is the vertical direction. The BB ′ direction is preferably a direction parallel to the direction in which most of the fibers are aligned. That is, the BB ′ direction is a direction parallel to the reference line of the planar direction obtained by a method described later.

In FIG. 1 (b), the reference line determined by the method is a dotted line indicated by P, and the orientation of each reinforcing fiber is indicated by a dotted line of Q and R, respectively. In addition, in FIG. 1 (b), the dashed line denoted by P 'is a line parallel to the reference line, and is an angle formed for easily understanding the reference line P and the alignment lines (Q and R) of each reinforcing fiber. Auxiliary line for explanation. In FIG. 1 (b), the angle (alignment angle θ ₁ ) formed by P ′ and Q is 0 °, so P ′ and Q overlap. The angle (alignment angle θ ₂ ) formed by P ′ and R is expressed as θ ₂ . In this way, θ ₁ to θ _{n were} measured. In addition, in FIG. 1 (b), in order to easily confirm the alignment state of the reinforcing fibers, only the reinforcing fibers are illustrated.

In addition, as a part for measuring the fiber alignment parameter (fp) or the fiber alignment parameter (fp (p _{± z} )) of the assumed reference line and the reinforcing fiber, it is preferable to avoid the section of the cross section in the thickness direction of the test piece for cross section observation. The end is set near the center. Specifically, it is preferable to set it as a measurement area by avoiding the area from the edge thickness direction of the both ends of the test piece for cross-section observation to 5% (5% with respect to the thickness of the test piece for cross-section observation).

In the present invention, the absolute value of the fiber alignment parameter (fp) of the reinforcing fibers in the thickness direction indicates that the reinforcing fibers and the fiber-reinforced plastic molded body are aligned so that the angle formed by the central surface becomes smaller within the range. Specifically, the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction within the above range indicates that when the sheet for a fiber-reinforced plastic molded body is heated and press-molded under the following conditions (a) and (b), In the obtained fiber-reinforced plastic molded article having a thickness of 1 mm, most of the reinforcing fibers in the reinforcing fibers existed substantially parallel to the center plane of the fiber-reinforced plastic molded article.

(a) Pressurization was performed at a pressure of 10 MPa and a pressure of 3.5 cm / sec.

(b) When the true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molded body is set to P, the sheet for the fiber-reinforced plastic molded body is pressurized and heated under the conditions of (a) above. When the bulk density (g / cm ³ ) of the obtained fiber-reinforced plastic molded article is Q, heating is performed so that Q / P ≧ 0.7.

The "mostly reinforcing fibers" refers to reinforcing fibers that are 80% or more of the total number of reinforcing fibers. The term "substantially parallel to the center plane of the fiber-reinforced plastic molded product" means that the angle formed by the center surface of the fiber-reinforced plastic molded product and the reinforcing fibers is aligned within ± 20 °. That is, a fiber-reinforced plastic molded body having a thickness of 1 mm obtained by performing heating and pressure molding under the conditions (a) and (b) is characterized in that 80% or more of the total number of reinforcing fibers is equal to that of the fibers. The angle formed by the central surface of the reinforced plastic molded body is aligned within ± 20 °.

The sheet for a fiber-reinforced plastic molded article of the present invention enables fiber-reinforced plastic More than 80% of the total number of reinforcing fibers in the molded body are aligned so that the angle formed with the center surface of the fiber-reinforced plastic molded body is within ± 20 °. In the present invention, the total number of reinforcing fibers is preferably 85% or more and aligned with an angle formed within the center plane of the fiber-reinforced plastic molded body within ± 20 °, and more preferably 90% or more. The angle formed by the center surface of the fiber-reinforced plastic molded body is aligned within ± 20 °. That is, most of the reinforcing fibers exist parallel to the center plane of the fiber-reinforced plastic molded body. Therefore, the density of the reinforcing fibers becomes high on the center plane or a plane parallel to the fiber-reinforced plastic molded body, and excellent bending strength is obtained. Furthermore, by setting the fiber alignment as described above, even when the fiber-reinforced plastic molded body catches fire, it is possible to suppress the occurrence of dripping matter derived from the thermoplastic resin.

Here, the center plane of the fiber-reinforced plastic molded product is a plane formed by connecting the average surface of the first surface and the midpoint of the average surface of the second surface of the fiber-reinforced plastic molded product as a center plane. The midpoint between the average surface of the first surface and the average surface of the second surface refers to the midpoint of the shortest distance between the specific point on the average surface of the first surface and the average surface of the second surface. In addition, the average surface of each surface refers to a surface having an average height passing through the heights of the concave portion and the convex portion when the surface has an uneven shape, and the average surface refers to each surface when the surface has no uneven shape.

FIGS. 2 (a) and 2 (b) are diagrams showing the orientation of reinforcing fibers in a surface parallel to the surface of a conventional fiber-reinforced plastic molded body 101. As shown in FIGS. 2 (a) and 2 (b), in the conventional fiber-reinforced plastic molded body 101, there are reinforcing fibers 20 aligned in a direction parallel to the surface of the fiber-reinforced plastic molded body 101, and along with the fiber reinforcement. Reinforced fibers aligned on the surface of the plastic molded body 101 in a vertical direction 20 '. There are also a plurality of reinforcing fibers having an angle with the surface of the fiber-reinforced plastic molded body 101.

When the conventional fiber-reinforced plastic molded body 101 is brought into contact with the flame 50 as shown in FIG. 2 (a), the droplet 60 of the thermoplastic resin melted from the existing fiber-reinforced plastic molded body 101 as shown in FIG. 2 (b). dropping. In addition, the dripping condition of the plastic molded body at the time of such burning can be achieved by contacting the fiber-reinforced plastic molded body 101 cut out to a predetermined size with a blue flame of 20 mm length prescribed in the UL94 flammability test for 10 seconds. Evaluate. Specifically, the dripping condition can be evaluated by the evaluation method described in the examples.

In the conventional fiber-reinforced plastic molded body 101, there are many reinforcing fibers aligned in a direction perpendicular to the surface, so that the density of the reinforcing fibers on a surface parallel to the surface becomes low. In addition, as the reinforcing fibers 20 ′ aligned in the vertical direction enter between the reinforcing fibers 20 aligned parallel to the surface of the fiber-reinforced plastic molded body 101, the distance between the reinforcing fibers increases. Therefore, the number of reinforcing fibers that the molten thermoplastic resin contacts is reduced, and the surface tension of the molten thermoplastic resin is not sufficiently exerted, so that 60 droplets of the molten thermoplastic resin are dropped.

3 (a) and 3 (b) are diagrams showing the orientation of reinforcing fibers in a cross section parallel to the surface of a fiber-reinforced plastic molded article 100 according to an embodiment of the present invention. As shown in FIGS. 3 (a) and 3 (b), in the fiber-reinforced plastic molded body 100 of the present invention, most of the reinforcing fibers 20 are aligned in a direction parallel to the surface of the fiber-reinforced plastic molded body 100.

Even when the fiber-reinforced plastic of the present invention is molded as shown in FIG. 3 (a) When the body 100 is in contact with the flame 50, as shown in FIG. 3 (b), it is difficult to drop the molten thermoplastic resin droplets 60 from the fiber-reinforced plastic molded body 100 of the present invention.

In the fiber-reinforced plastic molded article 100 of the present invention, fewer reinforcing fibers are aligned in a direction perpendicular to the surface, and the density of the reinforcing fibers on a surface parallel to the surface becomes higher. Further, the reinforcing fibers 20 aligned in a direction parallel to the surface are arranged without a gap, and the distance between the reinforcing fibers is shortened. Therefore, the number of reinforcing fibers in contact with the molten thermoplastic resin increases, the surface tension of the thermoplastic resin acts, and dripping of the droplets 60 of the molten thermoplastic resin can be suppressed. This improves the non-dripping property of the fiber-reinforced plastic molded article, and as a result, the flame retardancy is improved.

As described above, in the fiber-reinforced plastic molded article of the present invention, the non-dripping property can be improved by setting the alignment direction in the thickness direction of the reinforcing fibers to a predetermined direction. Therefore, the flame retardancy of the fiber-reinforced plastic molded article of the present invention is improved. When the sheet for a fiber-reinforced plastic molded article contains a flame retardant, the amount of the flame retardant can be reduced, and it is not necessary to add a large amount of flame retardant as in the past. As a result, it is possible to obtain a fiber-reinforced plastic molded body that also maintains the characteristics originally possessed by the thermoplastic resin. In addition, when a thermoplastic resin having an oxygen limiting index of 30 or more is used as the thermoplastic resin, a thermoplastic resin having an oxygen limiting index of less than 30 may be used in combination. Even in this case, the dripping resistance can be improved.

The fiber-reinforced plastic molded body having a thickness of 1 mm obtained by subjecting the sheet for a fiber-reinforced plastic molded body of the present invention to heat and pressure molding under the conditions (a) and (b) described above has a preferred geometric mean of bending strength. It is 200 MPa or more. The geometric mean of the bending strength is preferably 200 MPa or more, and more preferably 220 MPa or more. As described above, the density of the reinforcing fibers on the surface parallel to the surface of the fiber-reinforced plastic molded article Since the degree is high, the fiber-reinforced plastic molded article obtained in the present invention is excellent in mechanical strength.

Here, the geometric mean value of the bending strength is the orientation direction (machine direction (MD) direction) of the fibers in the fiber-reinforced plastic molded body and the direction (cross direction (CD)) orthogonal to the orientation direction of the reinforcing fibers. The geometric mean of bending strength in the direction) means the strength represented by the following formula.

Here, FMD represents bending strength in the MD direction, and FCD represents bending strength in the CD direction.

In addition, the absolute value of the fiber alignment parameter (fp) in the planar direction in the sheet for a fiber-reinforced plastic molded body may be 0 to 1.0. The absolute value of the fiber orientation parameter (fp) in the plane direction of the fiber-reinforced plastic molded body sheet may be 0.18 to 1.0, 0.25 to 1.0, or 0.3 to 1.0, or 0.6 to 1.0. That is, in the sheet for a fiber-reinforced plastic molded article of the present invention, in addition to the orientation in the thickness direction being a fixed direction, the orientation in the plane direction may also be a fixed direction.

At this time, the reinforcing fibers are parallel to the center plane of the fiber-reinforced plastic molded body and are aligned in one direction in the plane direction. The reinforcing fibers may be aligned in any direction in the plane direction of the fiber-reinforced plastic molded body, but are preferably aligned in the MD direction (flow direction of the papermaking line) of the fiber-reinforced plastic molded body. That is, the fiber-reinforced plastic molding obtained by molding the sheet for a fiber-reinforced plastic molding of the present invention under specific conditions In the body, the reinforcing fibers may be aligned parallel to the center plane and aligned in the MD direction (flow direction of the papermaking line).

The measurement of the fiber orientation parameter of the reinforcing fiber in the planar direction in the sheet for a fiber-reinforced plastic molded body can be performed without performing treatment such as resin embedding. Specifically, a sheet for cutting a fiber-reinforced plastic molded body having a length of 3 cm by a width of 3 cm can be placed on a slide glass, and the slide can be placed from above, and a normal reflected light can be used using a microscope. The measurement was observed.

In the present invention, one side of a test piece sandwiched by a glass slide is observed with an optical microscope. The optical microscope uses a microscope manufactured by Keynes Corporation to magnify the magnifiable monofilament, and observes the fiber using reflected light or a combination of reflected light and transmitted light. In this embodiment, for example, the magnification can be selected from 300 times, 600 times, and 800 times. Thereby, an arbitrary selected continuous measurement area of 2.0 mm ² was observed on one side, and the alignment angles θ _i of all the reinforcing fibers (the number of fibers is m) recognizable in the measurement area were measured. The alignment angle θ _i is an angle measured clockwise with respect to a reference line, and is set to an angle of 0 ° or more and less than 180 °. The fiber alignment parameter (fp, hereinafter also referred to as fp value) can be calculated from the alignment angle θ _i measured by the method described above using the following formula (2).

fp = 2 × Σ (cos ² θ _i / m) -1 Equation (2)

Among them, i = 1 ~ m.

In addition, the opposite surface was measured in the same manner, and the The average value is defined as the fiber orientation parameter (fp) in the plane direction. The measurement area on one side and the measurement area on the opposite side are, for example, areas that overlap in a plan view. In addition, in observation of any one surface and the opposite surface, for example, it is possible to observe 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 when measuring the fiber alignment parameter in the planar direction can be determined by the following method.

When a reference line is set, first, a hypothetical reference line p is selected, and the angles of all m reinforcing fibers recognizable in the measurement area are measured. At this time, it is assumed that the angle between the reference line p and each fiber is expressed by α (p) _i (i = 1 to m).

The fiber orientation parameter (fp (p)) when the reference line p is assumed can be calculated using the following formula.

fp (p) = 2 × Σ (cos ² α (p) _i / m) -1

(i = 1, 2, 3, ..., m)

Next, take the hypothetical baseline (p _{+ z} , p _-z (z = 1 ~ 90)) obtained by rotating the hypothetical baseline p in units of ± 1 ° until it becomes ± 90 °, and calculate the hypothetical baseline p _{+ z} and The angle of m fibers and the angle between the assumed reference line p _-z and the m fibers. The angle at this time is expressed by α (p _{+ z} ) _i and α (p _-z ) _i (i = 1 ~ m).

The assumed reference lines (p _{+ z} , p _-z (z = 1 to 90)) obtained by the rotation, and the fiber alignment 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)

In this way, the assumed reference line set when the maximum value is obtained among the obtained fp (p) value and fp (p _{± z} ) value may be used as the reference line P. The fiber alignment parameter calculated from the reference line P thus determined may be the fiber alignment parameter (fp) in the planar direction.

When the orientation of the thickness direction and the planar direction of the reinforcing fibers is a fixed direction, the fiber-reinforced plastic molded body obtained by molding the sheet for the fiber-reinforced plastic molded body more effectively improves the non-dripping property. Improved flame retardancy. Further, in the fiber-reinforced plastic molded body, the bending strength in one direction is improved. In particular, when the reinforcing fibers are aligned in the MD direction, the strength in the MD direction in the fiber-reinforced plastic molded body is improved. Such a fiber-reinforced plastic molded body can be preferably used for structural parts that require mechanical strength in one direction used in automobiles, airplanes, and the like.

In the sheet for a fiber-reinforced plastic molded article of the present invention, the blending ratio of the reinforcing fibers is preferably 20% by mass to 83% by mass. By setting the blending ratio of the reinforcing fibers within the above range, the number of fibers aligned in a specific direction can be increased. This shortens the distance between the reinforcing fibers, increases the packing density of the reinforcing fibers after heating and press molding, and can effectively increase the strength of the fiber-reinforced plastic molded body.

In addition, the quality of the reinforcing fiber and the thermoplastic resin is preferably 1: 0.2 to 1:10, more preferably 1: 0.5 to 1: 5, and even more preferably 1: 0.7 to 1: 3. By setting the mass ratio of the reinforcing fiber to the thermoplastic resin within the above range, light weight and High-strength fiber-reinforced plastic molded body.

The air permeability specified in the Pulp Test Method No. 5-2 of the Technical Association of the Pulp and Paper Industry of Japan (JAPAN TAPPI) of a sheet for a fiber-reinforced plastic molded body is preferably 250 seconds or less It is more preferably 230 seconds or less, and still more preferably 200 seconds or less. The smaller the number, the easier it is for air to pass through (the better the air permeability). In the present invention, by setting the air permeability of the sheet for a fiber-reinforced plastic molded body within the above range, the molding speed in the heating and pressing step can be increased, and production efficiency can be improved.

(Reinforced fiber)

The reinforcing fiber is preferably at least one selected from the group consisting of glass fiber, carbon fiber, and polyaramide fiber, and more preferably carbon fiber. These reinforcing fibers may be used alone or in combination. In addition, it may contain organic fibers having excellent heat resistance such as poly-para-Phenylene Benzoxazole (PBO) fibers.

When an inorganic fiber such as carbon fiber or glass fiber is used as the reinforcing fiber, the fiber-reinforced plastic molded body can be formed by performing a heating and pressure treatment at a melting temperature of a thermoplastic resin contained in the sheet for a fiber-reinforced plastic molded body. In addition, when an organic fiber such as polyaramide is used as the reinforcing fiber, the abrasion resistance can be further improved compared to a molded article generally formed from a sheet for a fiber-reinforced plastic molded article using an inorganic fiber as the reinforcing fiber.

The mass average fiber length of the reinforcing fibers is preferably 3 mm to 100 mm, more preferably 6 mm to 100 mm, still more preferably 6 mm to 75 mm, and even more preferably 6 mm to 50 mm. By setting the fiber length of the reinforcing fibers within the above range, the strength can be suppressed. The chemical fiber is detached from the sheet for a fiber-reinforced plastic molded body, and a fiber-reinforced plastic molded body having excellent strength can be formed. In addition, by setting the fiber length of the reinforcing fibers within the above range, the dispersibility of the reinforcing fibers can be made good. Thereby, the fiber-reinforced plastic molded body after heat-pressure molding has good strength and appearance.

In addition, in this specification, a mass average fiber length is the average value of the fiber length measured about 100 fibers.

In addition, the fiber diameter of the reinforcing fiber is not particularly limited in terms of the average fiber diameter. Generally, for carbon fibers and glass fibers, fibers having a fiber diameter of about 5 to 25 μm are suitably used. Moreover, a plurality of raw materials or shapes may be used in combination for the reinforcing fibers.

In this specification, the average fiber diameter is an average value of the fiber diameters obtained by measuring the fiber diameters of 100 fibers.

(carbon fiber)

As the reinforcing fiber, carbon fiber is preferably used. When carbon fibers are used, a fiber-reinforced plastic molded body having excellent strength can be molded. As the carbon fiber contained in the reinforcing fiber, polyacrylonitrile (PAN) -based, petroleum can be used. Carbon fibers such as coal coke pitch, rayon, and lignin. These carbon fibers may be used singly or in combination of two or more kinds. Among these carbon fibers, polyacrylonitrile (PAN) -based carbon fibers are preferably used from the viewpoint of industrial-scale productivity and mechanical characteristics.

The mass average fiber length of the carbon fiber is preferably 3 mm to 100 mm, more preferably 6 mm to 100 mm, still more preferably 6 mm to 75 mm, and even more preferably 6 mm to 50 mm. By setting the fiber length of the carbon fiber to the above range, the carbon fiber can be suppressed A fiber-reinforced plastic molded body which is detached from a sheet for a fiber-reinforced plastic molded body and has excellent molding strength. In addition, by setting the fiber length of the carbon fibers within the above range, the dispersibility of the reinforcing fibers can be made good. Thereby, the fiber-reinforced plastic molded body after heat-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. The monofilament strength refers to the tensile strength of the monofilament. When such a carbon fiber is used, the bending strength is greatly improved by utilizing the synergy effect of the effect of fiber alignment with the reinforcing fiber. The single fiber strength can be measured in accordance with JIS R7601 "Carbon fiber test method".

The fiber diameter of the carbon fiber is not particularly limited, and as a generally preferable range, it is preferably 5 μm to 20 μm. When the fiber diameter of the carbon fiber is within the above range, the strength of the fiber-reinforced plastic molded article can be increased.

(Alignment of reinforcing fibers)

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

The fiber reinforced plastic molded body having a thickness of 1 mm obtained by subjecting such a sheet for a fiber reinforced plastic molded body to heat and pressure molding under the conditions (a) and (b) has a strength of more than 80% of the total number of reinforcing fibers. The angle formed with the center surface of the fiber-reinforced plastic molded body exists within ± 20 °. Here, the conditions (a) and (b) are as follows.

(a) The pressure is applied at a pressure of 10 MPa and a pressure of 3.5 cm / sec. Pressure.

(b) When the true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molded body is set to P, the sheet for the fiber-reinforced plastic molded body is pressurized and heated under the conditions of (a) above. When the obtained fiber-reinforced plastic molded body has a bulk density (g / cm ³ ) of Q, heating is performed so that Q / P ≧ 0.7.

The condition (a) specifies a pressure condition, and is a pressure condition in which the pressure is set to 10 MPa and the pressure rate is set to 3.5 cm / sec. The pressing time is not particularly limited, and the sheet for a fiber-reinforced plastic molded article is heated and pressed under the conditions of (a) and (b), and the pressing is stopped until the press is stopped. After rising to the set temperature, the temperature was maintained for 5 minutes, and the temperature was cooled to a predetermined temperature.

In the condition (a), the pressing speed is set to 3.5 cm / sec. As long as the pressing speed is within a range of 3.5 cm / sec ± 0.5 cm / sec, the same pressing conditions as when pressing at a pressing speed of 3.5 cm / sec will be achieved. The sheet of the fiber-reinforced plastic molded body of the present invention originally has less orientation of the reinforcing fibers in the thickness direction. Therefore, even if the sheet is pressurized at a relatively high pressure, the orientation of the reinforcing fibers in the thickness direction in the formed body is reduced. By setting the pressing speed to 3.5 cm / sec, the fiber orientation of the reinforcing fibers in the fiber-reinforced plastic molded body can be appropriately evaluated.

Condition (b) specifies heating conditions, and when the true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molded article is set to P, the fiber-reinforced plastic is molded under the conditions of (a) above. When the body-density (g / cm ³ ) of the fiber-reinforced plastic molded article obtained when the body sheet is pressed and heated is set to Q, heating is performed so that Q / P ≧ 0.7.

The true density (g / cm ³ ) of the sheet for a fiber-reinforced plastic molded article, that is, the density of the solid itself without voids, is called the theoretical density. The mass density (g / cm ³ ) of the fiber-reinforced plastic molded body is Q, which refers to the mass per unit volume of the plastic molded body including both air permeability and non-air permeability. The fiber-reinforced plastic molded body sheet can be used. Is calculated by dividing the mass by the apparent volume.

The true density of the fiber-reinforced plastic molded sheet can be determined from the true density of the fibers constituting the nonwoven fabric and its mass ratio. Specifically, the true density of a sheet for a fiber-reinforced plastic molded body can be calculated by the following calculation formula.

The true density of the fiber-reinforced plastic molded sheet = (the true density of the reinforcing fiber × mass ratio) + (the true density of the thermoplastic resin × mass ratio) + (the true density of the binder × mass ratio)

The true density of the fiber-reinforced plastic molded sheet can be obtained by using a pycnometer method (liquid phase displacement method) or a gas phase displacement method in addition to the method described above.

The pycnometer method (liquid phase displacement method) is a method in accordance with JIS R 1620 "Method for Measuring Particle Density of Fine Ceramic Powders", and a sheet of a fiber-reinforced plastic molded body is immersed in a liquid such as an aqueous ethanol solution and butanol, A method for measuring volume based on the Archimedes principle. The true density of the sheet for a fiber-reinforced plastic molded body can be calculated by dividing the weight of the sheet for a fiber-reinforced plastic molded body by the volume measured by the above method.

The gas phase replacement method is a method in accordance with JIS R 1620 "Method for Measuring Particle Density of Fine Ceramic Powders", and is a method for measuring volume by replacement with helium gas or the like. The true density of the sheet for a fiber-reinforced plastic molded body can be calculated by dividing the weight of the sheet for a fiber-reinforced plastic molded body by the volume measured by the above method.

The bulk density of the fiber-reinforced plastic molded body can be obtained in the following procedure.

(1) The fiber-reinforced plastic molded sheet is stacked so that the basis weight becomes as described below. Weight per unit area (g / m ² ) = true density (g / cm ³ ) × 1 (mm) × 1000

(2) The laminate of the fiber-reinforced plastic molded body sheet of (1) is heated and press-molded so as to have a predetermined thickness, and the obtained molded body is cut into about 10 cm to 15 cm × 10 cm to 15 cm.

(3) The vertical (cm) and horizontal (cm) of the obtained molded body were measured using a vernier caliper. The thickness was measured with a micrometer at a total of 5 points at the four end portions and the center portion, and the average value (μm) of the thickness was obtained.

(4) The mass of the molded body is measured in units of 0.1 g.

(5) Based on the obtained data, the bulk density is obtained by the following formula.

Bulk density (g / cm ³ ) = mass of molded body (g) ÷ (length of molded body (cm) × width of molded body (cm) × thickness (μm) × 10 ^-4 )

When the fiber-reinforced plastic molded body is heated and pressed to form a fiber-reinforced plastic sheet, In the case of a plastic molded body, the above-mentioned step condition (a) and step condition (b) are performed simultaneously. Specifically, the heat and pressure treatment is performed simultaneously so as to satisfy the pressing conditions of (a) and the heating conditions of (b). The heat and pressure treatment is a treatment in which a stainless steel plate is arranged in parallel with each surface of the sheet for a fiber-reinforced plastic molded body, and is subjected to hot pressing. The stainless steel plate used here is a stainless steel plate having a surface finish of # 400 in Table 15 of JIS G4305 "Cold-rolled stainless steel plate and steel strip" and having a thickness of 2 mm. In the hot pressing, a spacer (a 1 mm thick plate) is preferably sandwiched between both ends. Thereby, a fiber-reinforced plastic molded body having a thickness of 1 mm can be molded.

When the heat and pressure treatment is performed, it is preferable to heat the hot press to 40 ° C in advance.

When the thermoplastic resin is a crystalline thermoplastic resin, the hot-pressing temperature during heating and pressure molding is preferably the melting point (Tm) of the thermoplastic resin + 30 ° C. In addition, when the thermoplastic resin is an amorphous thermoplastic resin, the hot-pressing temperature at the time of heating and pressure molding is preferably a glass transition temperature (Tg) of the thermoplastic resin + 100 ° C. The melting point and glass transition temperature of the thermoplastic resin can be determined by differential scanning calorimetry (DSC).

For example, the hot pressing temperature of a sheet for a fiber-reinforced plastic molded article containing the following thermoplastic resin is as follows. Polycarbonate and polyetherimide are amorphous thermoplastic resins, and polypropylene and nylon 6 are crystalline thermoplastic resins.

Polycarbonate: glass transition temperature Tg is 145 ° C, pressure temperature is 245 ° C

Polyetherimide: glass transition temperature Tg is 217 ° C, pressure temperature is 317 ° C

Polypropylene: Melting point Tm is 160 ° C, pressing temperature is 190 ° C

Nylon 6: Melting point Tm is 225 ° C, and pressing temperature is 255 ° C

In the fiber-reinforced plastic molded product having a thickness of 1 mm obtained by heating and press-molding the sheet for a fiber-reinforced plastic molded product of the present invention under the above conditions, 80% or more of the reinforcing fibers are aligned with the center surface of the fiber-reinforced plastic molded product. Orientation in parallel. Such a fiber-reinforced plastic molded body has excellent drip resistance and exhibits excellent bending strength.

In the fiber-reinforced plastic molded body obtained by heating and pressure molding under the conditions described above, the proportion of reinforcing fibers aligned so as to be within ± 20 ° with respect to the center plane is preferably 80% or more, more preferably 85% or more, more preferably 90% or more, particularly preferably 95% or more.

Here, the ratio of the reinforcing fibers aligned so as to be within ± 20 ° with respect to the center plane of the fiber-reinforced plastic molded article can be determined by the following method. Specifically, it can be obtained by cutting out a cross-section of a fiber-reinforced plastic molded body, and taking a picture using a three-dimensional measurement X-ray computed tomography (Computed Tomography, CT) device, and selecting 100 to 130 of the captured images Root reinforcing fibers were measured at an angle with the center plane.

In addition, the absolute value of the fiber alignment parameter (fp) in the planar direction in the sheet for a fiber-reinforced plastic molded body may be 0.25 to 1.0. In such a fiber-reinforced plastic molded article, the fiber reinforced plastic molded body having a thickness of 1 mm can be formed by heating and pressing under conditions (a) and (b). The faces are parallel and aligned in one direction. In particular, the reinforcing fibers may be arranged parallel to the center surface of the fiber-reinforced plastic molded body and arranged in the MD direction (flow direction of the papermaking line). to. By aligning in the MD direction as described above, it is possible to obtain a base material for a fiber-reinforced plastic molded body that can produce a fiber-reinforced plastic molded body that has good drip resistance and excellent strength in a specific direction.

(Thermoplastic resin)

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

The thermoplastic resin can be used alone or in combination as a thermoplastic resin in the form of fibers, powders, pellets, or flakes. Among them, the thermoplastic resin is preferably a thermoplastic resin fiber or a thermoplastic resin powder.

The "thermoplastic resin fiber" in this specification refers to a fibrous thermoplastic resin among thermoplastic resins. The thermoplastic resin fiber can be obtained by melt-spinning a thermoplastic resin. The flame retardant-containing thermoplastic resin fiber can be obtained by melt-spinning a flame retardant-containing thermoplastic resin. In addition, a thermoplastic resin fiber containing a flame retardant can also be obtained by mixing and spinning a flame retardant and a molten thermoplastic resin. In addition, a thermoplastic resin fiber having an oxygen limiting index of 30 or more can be obtained by melt-spinning a thermoplastic resin having an oxygen limiting 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 mm to 100 mm, more preferably 3 mm to 50 mm, and even more preferably 3 mm to 25 mm. By setting the fiber length of the thermoplastic resin fiber within the above range, the thermoplastic tree can be suppressed. The fat fiber is detached from the sheet for a fiber-reinforced plastic molded article, and a sheet for a fiber-reinforced plastic molded article having excellent handling properties can be obtained. In addition, by setting the fiber length of the thermoplastic resin fibers within the above range, the dispersibility of the thermoplastic resin fibers can be made good, and thus a fiber-reinforced plastic molded body having excellent strength can be formed. Furthermore, by setting the fiber length of the thermoplastic resin fibers within the above range, the thermoplastic resin fibers and the reinforcing fibers are uniformly mixed, and a fiber-reinforced plastic molded body having excellent molding strength can be formed. In this way, the fiber-reinforced plastic molded body formed by heat and pressure molding has good strength and appearance.

The "thermoplastic resin powder" in this specification refers to a powdery thermoplastic resin among thermoplastic resins. The thermoplastic resin powder can be obtained, for example, by freeze-pulverizing particles of a thermoplastic resin and classifying the particles with a mesh. The average primary particle diameter of the thermoplastic resin powder is preferably 3 μm to 7000 μm, more preferably 30 μm to 3000 μm, and even more preferably 100 μm to 1000 μm. In addition, when the thermoplastic resin powder is not spherical, the average primary particle diameter of the thermoplastic resin powder is the projection area of the particles obtained from a transmission electron microscope photograph, and the diameter of a circle having the same area is taken as the average primary particle diameter. By setting the average primary particle diameter of the thermoplastic resin powder within the above range, the web can be picked up, and a sheet for a fiber-reinforced plastic molded body can be obtained by a wet nonwoven fabric method. In addition, since the dispersibility of the thermoplastic resin powder can be improved, a fiber-reinforced plastic molded body having excellent strength can be formed. In this way, the fiber-reinforced plastic molded body formed by heat and pressure molding has good strength and appearance.

As the thermoplastic resin having an oxygen limiting index of 30 or more, a so-called resin called a super engineering plastic resin can be used. As a thermoplastic with an oxygen limiting index of 30 or more Examples of the resin include polyetheretherketone (PEEK), polyamidoamine (PAI), polyphenylene sulfide (PPS), polyetheramidoimine (PEI), and polyetherketone ketone (PEKK). )Wait. Among these, polyether fluorene imine (PEI) can be preferably used. Such a super engineering plastic fiber obtains flame retardancy even if it does not impart a flame retardant with its resin monomer. In addition, in the present invention, the "oxygen limit index" indicates an oxygen concentration required for continuous combustion, and means a value measured by a method described in JIS K7201. That is, an oxygen limit index of 20 or less is a value indicating that it can burn in normal air.

When the sheet for a fiber-reinforced plastic molded body contains a flame retardant, examples of the thermoplastic resin include polyester, polyethylene, polypropylene, polycarbonate (PC), polyamide (nylon 6, nylon 66), and acrylonitrile- Acrylonitrile Butadiene Styrene (ABS) resin and the like. Among them, polycarbonate (PC) and polyamide (nylon 6, nylon 66) can be preferably used. Polycarbonate due to formable bending strength. Modulus of elasticity. The fiber-reinforced plastic molded product which is excellent in impact resistance and the like is lightweight but high in strength, and therefore, it is preferable.

In the thermoplastic resin containing a flame retardant, the oxygen limiting index is also preferably a certain level or more. Specifically, the oxygen limit index in the fiber state is preferably 24 or more, and more preferably 27 or more. By setting the oxygen limit index of the thermoplastic resin containing a flame retardant to the above range, a fiber-reinforced plastic molded sheet and a fiber-reinforced plastic molded body having more excellent flame retardancy can be obtained.

The glass transition temperature of the thermoplastic resin is preferably 140 ° C or higher. The thermoplastic resin is required to sufficiently flow under a temperature condition such as 300 ° C to 400 ° C when forming a fiber-reinforced plastic molded body. In addition, even with glass transition temperature like PPS resin fiber The super engineering plastic fiber having a degree of less than 140 ° C can be used as long as the super engineering plastic fiber whose load deflecting temperature of the resin becomes 190 ° C or higher. This thermoplastic resin is heated. It melts under pressure to form a resin block having a very high flame retardancy having an oxygen limiting index of 30 or more.

A thermoplastic resin forms a tie point at the intersection of a matrix or a fiber component during heat and pressure treatment, and is therefore also referred to as a matrix resin. The sheet for a non-woven fiber-reinforced plastic molded body using such a thermoplastic resin does not require an autoclave treatment as compared to a sheet using a thermosetting resin, and the heating and press molding time during processing can be shorter, and Improve productivity.

In the sheet for a fiber-reinforced plastic molded body used in the present invention, the thermoplastic resin is preferably formed into a fibrous form, and in this case, there are voids in the sheet.

When the thermoplastic resin is formed into a fibrous form, the thermoplastic resin fiber maintains the fibrous form before being heated and pressurized. Therefore, before the fiber-reinforced plastic molded body is formed, the sheet itself is soft and has drape. Therefore, the sheet for a fiber-reinforced plastic molded body can be stored in a rolled form. Conveying, and has the characteristics of excellent handling.

(Flame retardant)

Examples of the flame retardant include a halogen-based flame retardant, a phosphorus-based flame retardant, and a silicone-based flame retardant.

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, and brominated bisphenol. Phenol A, glycidyl brominated bisphenol A, polypentabromobenzyl acrylate, osmium bromide, etc. Carbonates, brominated polystyrene resins, brominated bisphenol A glycidyl esters, and pentabromobenzyl polyacrylate tend to suppress the drop in impact resistance and are more preferred.

Examples of the phosphorus-based flame retardant include ethyl phosphinic acid metal salt, diethylphosphinic acid metal salt, melamine polyphosphate, phosphate ester, phosphazene, and the like. Among them, those having excellent thermal stability In terms of metal diethylphosphinic acid, melamine polyphosphate, and phosphazene. In addition, in order to suppress the generation of gas or mold deposits during molding and bleeding out of the flame retardant, a thermoplastic resin having excellent compatibility with a phosphorus-based flame retardant may be blended. As such a thermoplastic resin, a polyphenylene ether resin, a polycarbonate resin, and a styrene resin are preferable.

Furthermore, you may mix a flame retardant adjuvant with a flame retardant. Examples of the flame retardant aid include copper oxide, magnesium oxide, zinc oxide, molybdenum oxide, zirconia, tin oxide, iron oxide, titanium oxide, aluminum oxide, antimony compounds, zinc borate, and the like, and two or more of them may be used in combination. Among these, an antimony compound and zinc borate are preferable from a viewpoint of being more excellent in flame retardance.

Examples of the antimony compound include antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), and sodium antimonate. In particular, when a halogen-based flame retardant is used, in view of the synergistic effect with the flame retardant, it is preferable to use antimony trioxide in combination. When a flame retardant auxiliary is used, it is preferable that the flame retardant auxiliary is also contained in the thermoplastic resin together with the flame retardant.

The method for including a flame-retardant in the sheet for a fiber-reinforced plastic molded body is not limited, and the following methods are mentioned. Examples include: (1) a method for forming a sheet for a fiber-reinforced plastic molded body using a thermoplastic resin containing a flame retardant; (2) mixing a particulate flame retardant into a slurry of the reinforcing fiber and the thermoplastic resin and wet Square papermaking (3) forming a sheet for a fiber-reinforced plastic molded body using a thermoplastic resin containing a flame retardant, and impregnating the sheet with a slurry, an aqueous solution, an emulsion, or the like of the flame retardant by a method such as dipping And carry out the drying method. These methods can also be used in combination.

When the sheet for a fiber-reinforced plastic molded article contains a flame retardant, the thermoplastic resin preferably contains a flame retardant. The "thermoplastic resin containing a flame retardant" in this specification refers to a thermoplastic resin blended with a flame retardant in order to impart flame retardancy. As a flame retardant, the said flame retardant is mentioned as a preferable example. In addition, the flame retardant is preferably uniformly dispersed in the thermoplastic resin, and a thermoplastic resin having a flame retardant adhered on its surface may be used. Examples of the thermoplastic resin containing a flame retardant include the same thermoplastic resins as those used when the sheet for a fiber-reinforced plastic molded article contains a flame retardant.

(Binder composition)

In the present invention, the binder component is preferably contained so as to be 0.1% to 10% by mass relative to the total mass of the fiber-reinforced plastic molded body sheet, more preferably 0.3% to 10% by mass, and even more preferably It is 0.4% to 9% by mass, and particularly preferably 0.5% to 8% by mass. When the content rate of the binder component is within the above range, the strength in the manufacturing step can be improved, and the handleability can be improved. In addition, if the amount of the binder component is increased, although the surface strength. The interlaminar strength will become stronger. Conversely, the problem of odor is easy to occur during heating molding. However, in this range, a problem of substantially no odor is generated, and a sheet for a fiber-reinforced plastic molded body that does not undergo peeling or the like even after repeated cutting steps can be obtained.

As the adhesive component, a polymer used in ordinary nonwoven fabric production can be used. Polyester resins such as ethylene terephthalate, modified polyethylene terephthalate, and core-sheath structured binder fibers, acrylic resins, and styrene- (meth) acrylate copolymers Resins, urethane resins, polyvinyl alcohol (Polyvinyl Alcohol, PVA) resins, various starches, cellulose derivatives, sodium polyacrylate, polyacrylamide, polyvinylpyrrolidone, acrylamide-acrylic acid Ester-methacrylate copolymer, styrene-maleic anhydride copolymer alkali metal salt, isobutylene-maleic anhydride copolymer alkali metal salt, polyvinyl acetate resin, styrene-butadiene copolymer , Vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, styrene-butadiene- (meth) acrylate copolymer, and the like. In addition, a polyester resin and a polypropylene resin can be suitably used, and a synthetic pulp using a resin obtained by modifying these resins and appropriately adjusting the melting point can obtain sufficient strength even in a small amount, which is preferable.

The binder component is preferably a copolymer containing at least one of a repeating unit derived from a monomer containing methyl (meth) acrylate and a repeating unit derived from a monomer containing ethyl (meth) acrylate. Among these, the adhesive component is preferably a copolymer containing 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. Moreover, these monomers can also be copolymerized with other monomers, such as styrene, or vinyl acetate, acrylamide, and the like.

In the present invention, "(meth) acrylate" refers to both "acrylate" and "methacrylate", and "(meth) acrylic" refers to "acrylic" and "methacrylic" Both.

(Fiber shape)

In the present invention, the thermoplastic resin fiber and the reinforcing fiber are preferably cut into a fixed length. Chopped strands. Moreover, the binder fiber is also preferably a chopped strand. By adopting such a configuration, various fibers can be uniformly mixed in the sheet for a fiber-reinforced plastic molded body. In addition, the cross-sectional shape of the fiber is not limited to a circular shape, and a fiber with an irregular cross-section such as an oval shape may be used.

When manufacturing the sheet for a fiber-reinforced plastic molded article of the present invention, the following method (wet nonwoven fabric method) is adopted: the chopped strands of thermoplastic resin fibers, reinforcing fibers, and binder fibers are dispersed in a solvent, and the solvent is removed to form Web.

(Manufacturing method of fiber-reinforced plastic molded sheet)

The manufacturing process of the sheet | seat for fiber-reinforced plastic moldings of this invention includes the process of wet-paper-making the slurry which mixed the reinforcement fiber and thermoplastic resin fiber. Here, the thermoplastic resin fiber is a thermoplastic resin fiber having an oxygen limiting index of 30 or more, or a sheet for a fiber-reinforced plastic molded body contains a flame retardant. The step of performing wet papermaking includes the step (A) or the step (B).

(A) A step of papermaking using a cylinder paper machine at a papermaking speed of 5 m / min or more.

(B) A step of making paper using a Fourdrinier paper machine or an inclined paper machine. When the step of performing wet papermaking includes (B) the step of making paper using a Fourdrinier or inclined papermaking machine, the net portion of the Fourdrinier or inclined papermaking machine moves so that the pulp-to-speed ratio becomes 0.95 or less .

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

When using a cylinder paper machine for papermaking, the The diameter is preferably 50 cm or more. By setting the diameter of the cylinder of the cylinder paper machine to the above-mentioned range, 80% or more of the reinforcing fibers can be aligned parallel to the center plane of the fiber-reinforced plastic molded body, and the dripping resistance can be further improved.

The papermaking speed when using a cylinder paper machine to make paper is preferably 3 m / min or more, more preferably 5 m / min or more, and even more preferably 10 m / min or more. By setting the papermaking speed to the above range, 80% or more of the reinforcing fibers can be aligned parallel to the center surface of the fiber-reinforced plastic molded body, and the dripping resistance can be further improved.

When a cylinder paper machine is used for papermaking, there are two methods for introducing raw materials into the layer: a forward flow method and a countercurrent flow method. The forward flow method is a method of introducing the raw material in the same direction as the rotation direction of the net portion, and the counter current method is the method of introducing the raw material in the direction opposite to the rotation direction of the net portion. In the present invention, when the raw material supply is set to the countercurrent method, the reinforcing fibers are more easily aligned in one direction.

In addition, in the step of performing wet papermaking, in addition to a cylinder papermaking machine, a fourdrinier papermaking machine or an inclined papermaking machine may be used. That is, in the manufacturing step of the fiber-reinforced plastic molded sheet of the present invention, the step of performing wet papermaking may be a step of papermaking using a Fourdrinier papermaking machine or an inclined papermaking machine. Here, in the step of using a Fourdrinier papermaking machine or an inclined papermaking machine to perform papermaking, the screen portion of the Fourdrinier papermaking machine or the inclined papermaking machine moves so that the pulp-to-speed ratio becomes 0.95 or less.

In addition, the step of performing wet papermaking is preferably a step of using a fourdrinier papermaking machine or an inclined papermaking machine, and more preferably, a step of performing papermaking using an inclined papermaking machine.

Here, the pulp-to-web speed ratio is a ratio of the supply speed of the slurry liquid of the fiber to the moving speed of the mesh portion, and is expressed by the supply speed of the slurry liquid of the fiber / moving speed of the mesh portion. When the pulp-to-web speed ratio is greater than 1, the supply speed of the pulp slurry of the fiber is faster than the moving speed of the web part, and this case is called a "squeeze form". In addition, when the pulp-to-web speed ratio is less than 1, the supply speed of the pulp slurry of the fiber is slower than the moving speed of the web part, and this case is referred to as a "stretching form".

In the manufacturing method of the present invention, when a Fourdrinier papermaking machine or an inclined papermaking machine is used, the pulp and wire speed ratio may be 0.95 or less. In the manufacturing method of the present invention, the absolute value of the fiber alignment parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded body can be set to a desired value by setting the pulp-to-speed ratio to the above range. Within range.

When the step of performing wet papermaking is a step of using a tilted papermaking machine to perform papermaking, it is preferable to appropriately appropriately draw the attraction of a plurality of wet suction boxes provided in the inclined web portion of the tilted papermaking machine. Adjustment. Specifically, it is preferable to adjust so that the amount of dehydration of the wet suction box on the downstream side of the inclined net portion increases. In general, when the suction force of a wet suction box is made uniform, there is a tendency that the amount of dewatering on the upstream side of the net portion where the amount of fibers of the wet web accumulated on the net portion is small increases and the amount of dehydration is accumulated on the net portion. The amount of fibers on the downstream side decreases as the amount of dehydration decreases. Therefore, in the present invention, the attraction force on the upstream side is made weaker than the attraction force on the downstream side, and the amount of dehydration of the wet suction box on the downstream side of the inclined net portion is adjusted to increase the fiber-reinforced plastic on the net portion. The molded body sheet is uniformly dehydrated. By uniformly dehydrating as described above, the absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the sheet for a fiber-reinforced plastic molded body can be within a 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 (the measurement method specified in JIS Z 8803 “Method for Measuring Liquid Viscosity”) is preferably more than 1.00. mPa. s and 4.00 mPa. Below s, more preferably 1.05mPa. s ~ 2.00mPa. s.

The slurry referred to herein is a slurry immediately before the papermaking step, and is a slurry in an inlet. When measuring the viscosity of the dispersion medium of the slurry, 500 ml of the slurry was taken from the inlet, and the filtrate was measured using a filtrate obtained by filtering the fibers through a 150-mesh metal sieve.

The viscosity of the dispersion medium of the slurry can be adjusted by adding a thickener such as a polypropylene ammonium system to the inlet. By setting the viscosity of the dispersion medium of the slurry within the above range, it is possible to suppress the flow disturbance of the dispersion liquid in the vicinity of the mesh portion to form a laminar flow. Thereby, the fiber alignment parameter (fp) in the thickness direction of the sheet for a fiber-reinforced plastic molded body can be brought into a desired range.

The step of performing wet papermaking preferably includes a step of adding, coating or impregnating a non-woven fabric sheet with a solution containing a binder component or an emulsion containing a binder component, and heating and drying. That is, the step of forming a sheet for a fiber-reinforced plastic molded article preferably includes a step of performing wet papermaking by a wet nonwoven fabric method, and a step of adding, coating, or impregnating a nonwoven fabric sheet with a solution containing an adhesive component or the like. Furthermore, after the internal addition, coating, or impregnation, a step of heating and drying is included. By providing such a step, it is possible to suppress scattering, fluffing, or falling off of fibers on the surface of the sheet for a fiber-reinforced plastic molded article, and obtain a sheet for a fiber-reinforced plastic molded article having excellent handleability.

In addition, a solution containing a binder component or a milk containing a binder component After adding, coating, or impregnating the sheet for a fiber-reinforced plastic molded body in liquid, it is preferable that the sheet for a fiber-reinforced plastic molded body is rapidly heated. By providing such a heating step, the solution containing the binder component or the emulsion containing the binder component can be transferred to the surface layer region of the sheet for a fiber-reinforced plastic molded body. Furthermore, the adhesive component can be locally present in a water-repellent film form.

(Fiber-reinforced plastic molded body)

The sheet for a fiber-reinforced plastic molded article of the present invention can be processed into an arbitrary shape in accordance with the shape or molding method of a target molded article. The sheet for a fiber-reinforced plastic molded body can be formed alone or laminated to have a desired thickness, and then heated and press-molded by hot pressing, or pre-heated by an infrared heater or the like, and heated by a mold. Compression molding. In this way, a fiber-reinforced plastic molded body having excellent strength can be produced by processing using a heat and pressure molding method using a general sheet for a fiber-reinforced plastic molded body.

In the fiber-reinforced plastic molded product of the present invention, the absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction is 0.5 to 1.0. This indicates that most of the reinforcing fibers in the reinforcing fibers exist substantially parallel to the center plane of the fiber-reinforced plastic molded body. In addition, "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 molded article" means that the angle formed by the center plane of the fiber-reinforced plastic molded article and the reinforcing fibers is aligned within ± 20 °.

The thickness of the fiber-reinforced plastic molded body is not particularly limited, and when used as a case for a mobile device or the like, it is preferably thin from the viewpoint of weight reduction. in particular, It is preferably 0.1 mm to 50.0 mm, more preferably 0.1 mm to 10.0 mm, and still more preferably 0.4 mm to 1.0 mm. In addition, the flame retardancy tends to decrease when the thickness is thin, but even if the fiber-reinforced plastic molded article of the present invention has a thickness in the above range, dripping can be suppressed during combustion, and the flame retardancy is sufficiently improved.

The fiber-reinforced plastic molded article of the present invention is excellent in non-dripping property. Specifically, it is preferable to cut a fiber-reinforced plastic molded body into a test piece having a width of 13 mm and a length of 125 mm (the thickness is arbitrary). The upper end of the test piece is attached to a clamp, and When the lower end (the side in the width direction) is in contact with a flame having a length of 20 mm in the center for 10 seconds, the surgical absorbent cotton installed at 12 inches under the fiber-reinforced plastic molded body does not catch fire. This means that when the fiber-reinforced plastic molded body is exposed to a flame, the molten material of the fiber-reinforced plastic molded body does not drip as a dripping substance, or the amount of dripping is extremely small. In addition, the test is a method according to the UL94 vertical flammability test of the Underwriters Laboratories (UL) standard.

The geometric mean of the bending strength in the MD direction and the bending direction in the CD direction of the fiber-reinforced plastic molded product is preferably 200 MPa or more, more preferably 220 MPa or more, still more preferably 250 MPa or more, and even more preferably 280 MPa or more.

(Molding method of fiber-reinforced plastic molded body)

The method for forming the sheet for a fiber-reinforced plastic molded article of the present invention is not particularly limited, and can be selected according to the use of the molded article and the like. As a representative method, press molding can be exemplified. In addition, as a method of pressure molding, among various methods of pressure molding, an autoclave method often used when manufacturing a molded body member such as a large aircraft, or a mold pressing method with relatively simple steps can be preferably cited. law. Get pores From the viewpoint of a high-quality molded body having a small number of voids, the autoclave method is preferred. On the other hand, from the viewpoints of energy consumption of equipment or molding steps, simplification of molding jigs and auxiliary materials used, freedom of molding pressure, and temperature, it is preferable to use a mold that is molded using a metal mold. The pressure method can be selected according to the application.

In the mold pressing method, a heat & cool method or a stamping molding method can be adopted. The hot-cold method is a method in which a sheet for a fiber-reinforced plastic molded body is placed in a mold in advance, clamped, pressurized, and heated, and then the sheet is cooled by cooling the mold in a clamped state. Thus, a molded body was obtained. The press molding method is a method in which the sheet is heated in advance by a heating device such as a far-infrared heater, a hot plate, a high-temperature oven, and dielectric heating, and the thermoplastic resin is melted and softened and then placed inside the molded body mold. Then, the mold is closed and clamped, followed by pressure cooling. In addition, when the temperature at the time of molding, such as when a low-density molded body is obtained, is relatively low, a hot pressing method may also be adopted.

There are roughly two types of molding dies, one is a closed mold used for casting or injection molding, and the other is an open mold used for pressure molding or forging. When using the sheet for a fiber-reinforced plastic molded article of the present invention, any one of the molds may be used depending on the application. From the viewpoint of excluding the decomposed gas or mixed air during molding from the mold, it is preferable to open the mold. However, in order to suppress the excessive outflow of resin, it is also preferable to use as small a part as possible to suppress the resin during molding. Shape flowing out of the mold.

Further, as the mold, a mold having at least one selected from a punching mechanism and a tapping mechanism can be used. By using a design such as a two-stage pressurizing mechanism, it is also possible to continuously punch the molded body after hot pressing. Moreover, the molded body can be reinforced with ribs or bosses according to the purpose of use. Formation of processing protrusions or screw holes, and provision of a pattern for the purpose of providing designability.

In addition, while the fiber-reinforced plastic molded body sheet is being molded, or after the molding, a more complicated shape member may be formed by using injection molding or insert molding.

When forming a fiber-reinforced plastic molded body from a sheet for a fiber-reinforced plastic molded body, in the case of using a thermoplastic resin as a matrix resin, it is preferable to add a sheet for a fiber-reinforced plastic molded body containing a resin at 150 ° C to 600 ° C. Compression molding. The heating temperature is preferably a temperature at which the thermoplastic resin fibers flow and a temperature range at which the reinforcing fibers do not melt.

The pressure at the time of molding the resin-containing fiber-reinforced plastic molded body sheet is preferably 0.5 MPa to 20 MPa. From the viewpoint of suppressing the breakage of the reinforcing fibers and improving the strength, it is more preferably 0.5 MPa to 10 MPa, and even more preferably 1 MPa to 8 MPa. When using a thermosetting resin, or when impregnating a fiber-reinforced plastic molded body with a curing agent before impregnating the resin with the curing agent, and using a resin cured at normal temperature, the molding temperature may be appropriately set according to the resin. In addition, when the resin is used, the fiber-reinforced plastic molded body can be formed by applying pressure only without heating.

(Applications of fiber-reinforced plastic moldings)

As the use of the fiber-reinforced plastic molded article of the present invention, for example, it is suitable for use in "Office Automation (OA) equipment, mobile phones, smartphones, personal digital assistants, personal computers (PCs), and digital cameras ( digital video camera) and other mobile electronic equipment, housings for air conditioners and other home appliances, and reinforcing materials such as ridges attached to the housing, and civil and building materials such as "pillars, panels, and reinforcing materials" , "Various frames, various wheel bearings, various beams, doors, trunk lids, side panels, upper back panels, front body ( front body), under body, various pillars, various supports and other outer panels or body parts and their reinforcements '', fuel cell separators or diffusion layers, `` instrument panels (Instrument panels, sheet frames, and other interior parts ", or" gasoline tanks, various piping, and various valves (valves) and other fuel systems, exhaust systems, or suction system parts "," Engine cold Water connectors, thermostat bases for air conditioners, headlamp support, pedal housing, etc., automotive, two-wheelers parts, `` winglets, interference "Spoiler" and other aircraft parts, "railway seat members, skin panels, external panels reinforced materials, roof panels, air outlets, etc." rail vehicle parts , "Reinforcing material containing molded articles of resin (thermosetting resin, thermoplastic resin), reinforcing material containing molded articles of resin and reinforcing fibers, plant-derived sheets (kraft paper, cardboard, oil-resistant paper, Insulating paper, conductive paper, release paper, impregnated paper, glassine paper, cellulose nano Fiber sheet (cellulose nanofiber sheet), etc. "and other components.

As described above, the fiber-reinforced plastic molded product of the present invention has high strength and excellent drip resistance, and therefore has high safety. Therefore, the fiber-reinforced plastic molded product of the present invention can be preferably used for housings for electric and electronic equipment, structural parts for automobiles, and aircraft. Parts, civil engineering, building material panels, and various other uses.

[Example]

Hereinafter, the characteristics of the present invention will be described more specifically with examples and comparative examples. The materials, usage amounts, proportions, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed as long as they do not depart from the scope of the gist of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific examples shown below.

<Example 1>

(Manufacture of flame retardant-containing polycarbonate fiber)

Polycarbonate resin (component A) (manufactured by Mitsubishi Engineering-Plastics Corporation, trade name: Iupilon S-3000 (viscosity average molecular weight: 21,000)), acrylonitrile. Styrene-based copolymer (component B) (manufactured by Techno Polymer Co., Ltd.), trade name: 290FF (melt flow rate at 220 ° C, load of 49N, MFR): 50g / 10min)), polycarbonate oligomer (component C) (manufactured by Mitsubishi Gas Chemical Inc., trade name: AL071 (average degree of polymerization: 7)), and phosphorus Flame retardant (component D) (phosphate ester, manufactured by DAIHACHI Chemical Industry 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 ) is mixed so that the mass ratio becomes 100 / 5.5 / 12/16. The mixture was melt-mixed using a 30 mmΦ biaxial extruder to obtain a pelletized resin composition.

At a spinning temperature of 300 ° C, the obtained pellets were melt-extruded using a spinning nozzle (hole diameter of 0.6 mm), and the temperature near the spinning nozzle was cooled to 250 ° C to obtain a spinning filament having a fineness of 100 dtex ( filament). The obtained filament was cut into a length of 15 mm with a Guillotine cutter to obtain a polycarbonate fiber containing a flame retardant.

As described in Example 1 of Table 1, PAN-based carbon fibers (fiber length: 12 mm), the flame retardant-containing polycarbonate fibers (fiber length: 15 mm), and a polyethylene synthetic slurry as a binder ( Manufactured by Mitsubishi Chemical (SWP AU690), and metered into water in such a manner that the PAN-based carbon fiber is 35 parts by mass with respect to the total mass of the fiber-reinforced plastic molded sheet, and polycarbonate containing a flame retardant The resin fiber was 62 parts by mass, and the polyethylene synthetic slurry was 3 parts by mass. Furthermore, the amount of water input was 200 times the total mass of the PAN-based carbon fiber and the polycarbonate resin fiber (that is, 0.5% in terms of fiber slurry concentration).

To this slurry, a product name "Emanon 3199" (manufactured by Kao Corporation) was added as a dispersion to 100 parts by mass with respect to 100 parts by mass of the fibers (total of PAN-based carbon fibers and polycarbonate fibers) as a dispersion. The agent was stirred and a fiber slurry was prepared by uniformly dispersing the fibers in water.

The fiber slurry was continuously fed countercurrently to a cylinder paper machine to form a wet mesh sheet. Then, a Yankee dryer and a hot air dryer included in the papermaking machine were used for heating and drying at 180 ° C. Thus, a sheet for a fiber-reinforced plastic molded body having a basis weight of 145 g / m ² was obtained. The papermaking speed was set to 15 m / min. Furthermore, when the fiber slurry is fed to a cylinder paper machine to form a wet mesh sheet, an anionic polymer polypropylene ammonium thickener "Sumifloc FA40HRS (MT Polymer Polymer Co., Ltd. (manufactured by MT AquaPolymer Inc.) "0.03% concentration of the aqueous solution, the viscosity of the dispersion medium of the slurry The measured liquid temperature (viscosity at 25 ° C) was adjusted as shown in Table 1 and then copied to obtain a sheet for a fiber-reinforced plastic molded body.

The dispersion medium of the slurry was a filtrate obtained by taking 500 ml of the slurry at the inlet and filtering the fibers through a 150 mesh metal sieve. The absolute value of the fp value of the sheet for a fiber-reinforced plastic molded body is shown in Table 1.

<Production of Fiber-reinforced Plastic Molded Body for Measuring Angle of Reinforced Fibers and Measuring Flexural Strength>

Nine sheets of each of the obtained fiber-reinforced plastic molded bodies were stacked, the pressing speed was increased at 3.5 cm / sec, the pressing pressure was set to 10 MPa, and the temperature was raised to 260 ° C. After heating and pressing for 60 seconds, it was cooled. At 70 ° C, a fiber-reinforced plastic molded body having a thickness of 1.0 mm was obtained. Table 1 shows the true density (g / cm ³ ) of the fiber-reinforced plastic molded body sheet as P, and the bulk density (g / cm ³ ) as Q.

<Production of Fiber Reinforced Plastic Molded Body for Burning Test>

The obtained sheet for a fiber-reinforced plastic molded article was formed into a stack as described in Table 1. The number of laminations is stacked, the pressing speed is increased at 3.5 cm / sec, the pressing pressure is set to 10 MPa, the temperature is raised to 260 ° C, and the heating and pressing are performed for 60 seconds, and then cooled to 70 ° C to obtain the table 1 Fiber reinforced plastic molded body.

<Example 2>

In Example 2, the papermaking machine used to form the wet mesh sheet of Example 1 was changed to an inclined wire-type papermaking machine (wire machine) to adjust the white water circulation flow rate, anionic high-molecular-weight polyacrylamide-based thickener, and Speed, adjust the pulp to wire speed ratio to 0.90. Except for this, a sheet for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1. At this time, the attractive forces of the four dewatering tanks included in the net portion of the tilted net papermaking machine were adjusted, and the four dehydration tanks were adjusted so that the amounts of dewatering became approximately the same. Furthermore, the viscosity of the dispersion medium of the slurry (using JIS) was adjusted by appropriately adding an aqueous solution of an anionic high-molecular polyacrylamide-based thickener "Sumifloc (manufactured by MT Okko Polymer Co., Ltd.)" into the inlet. Z 8803 "Liquid viscosity measurement method" (the viscosity at a liquid temperature of 25 ° C measured by the measurement method specified in the measurement method) is adjusted as shown in Table 1 and then copied.

Except for this, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforcing fiber, and a measurement of flexural strength, and a fiber-reinforced plastic molded body for a combustion test were produced in the same manner as in Example 1.

<Example 3>

Except that the viscosity of the dispersion medium was shown in Table 1, and the pulp-to-speed ratio was adjusted to 0.50, a sheet for a fiber-reinforced plastic molded body, an angle measurement for reinforcing fibers, and Fiber-reinforced plastic for measuring flexural strength Moldings and fiber-reinforced plastic moldings for combustion tests.

<Example 4>

Except setting the viscosity of the dispersion medium as shown in Table 1, setting the fiber length of the PAN-based carbon fibers to 25 mm, and adjusting the pulp-to-web speed ratio to 0.25, a fiber-reinforced plastic molding was made in the same manner as in Example 2. Sheets for body use, fiber-reinforced plastic molded bodies for measuring the angle of reinforced fibers and measurement of flexural strength, and fiber-reinforced plastic molded bodies for combustion tests.

<Example 5>

PAN-based carbon fibers were prepared in an amount of 40 parts by mass with respect to the total mass of the fiber-reinforced plastic molded body sheet, and 57 parts by mass of the polycarbonate resin fibers containing a flame retardant, and the viscosity of the dispersion medium was set as shown in Table 1. In addition, except that the pulp-to-web speed 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 the reinforcing fiber, and a measurement of the flexural strength were produced in the same manner as in Example 2. And fiber-reinforced plastic moldings for combustion tests.

<Example 6>

A sheet for a fiber-reinforced plastic molded body, an angle measurement for reinforcing fibers, and a bending strength were produced in the same manner as in Example 1 except that the viscosity of the dispersion medium was as shown in Table 1, and the raw material slurry was supplied downstream. Fiber-reinforced plastic molded body for measurement and fiber-reinforced plastic molded body for combustion test.

<Example 7>

The flame-retardant polycarbonate fiber was changed to a polyether-imide fiber (made by Kuraray Co., Ltd., and the fiber diameter was 2.2 dtex × 15 mm). Except that the viscosity of the dispersion medium is shown in the table, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforcing fiber, and a measurement of the flexural strength were produced in the same manner as in Example 6, respectively. And fiber-reinforced plastic moldings for combustion tests.

<Example 8>

The flame retardant polycarbonate fiber was changed to a polyetherimide fiber (made by Kuraray Corporation, and the fiber diameter was 2.2 dtex × 15 mm), and the viscosity of the dispersion medium was shown in Table 1. In the same manner as in Example 2, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforced fiber and a measurement of flexural strength, and a fiber-reinforced plastic molded body for a combustion test were produced.

<Example 9>

A flame retardant nylon 6 fiber was used in place of the flame retardant polycarbonate fiber used in Example 8, and the viscosity of the dispersion medium was shown in Table 1. The methods were separately produced in the same manner as in Example 8. A sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforced fiber and a measurement of flexural strength, and a fiber-reinforced plastic molded body for a combustion test. In addition to flame retardant nylon 6 fibers, nylon 6 resin particles (Unitika Nylon 6 A1030JR manufactured by Unitika Ltd.) are used instead of the A component used in the production of flame retardant polycarbonate resin. The components other than the B component and the C component were produced according to the method for producing a flame-retardant polycarbonate resin fiber of Example 1.

<Example 10>

A part of the flame-retardant polycarbonate fiber of Example 8 was replaced with polyether fluorene Amine fibers were prepared as shown in Table 1, and the viscosity of the dispersion medium was set as shown in Table 1. Except that the sheet for fiber-reinforced plastic moldings and the angle of the reinforcing fibers were produced in the same manner as in Example 8, Fiber-reinforced plastic molded bodies for measurement and measurement of flexural strength, and fiber-reinforced plastic molded bodies for combustion tests.

<Example 11>

A part of the polyether sulfonimide fiber of Example 8 was changed to a polycarbonate fiber (made by Daiwabo Polytec Co, Ltd., 30 μΦ × 15 mm), and blended as shown in Table 1, and Except that the viscosity of the dispersion medium was as shown in Table 1, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforcing fiber, and a measurement of the flexural strength were produced in the same manner as in Example 8. And fiber-reinforced plastic moldings for combustion tests.

<Example 12>

In Example 7, except that the carbon fiber was changed to glass fiber, blended as shown in Table 1, and the viscosity of the dispersion medium was set as shown in Table 1, a fiber-reinforced plastic was produced in the same manner as in Example 7. A sheet for a molded body, a fiber-reinforced plastic molded body for measuring the angle and bending strength of reinforcing fibers, and a fiber-reinforced plastic molded body for a combustion test.

<Example 13>

In Example 8, except that the carbon fiber was changed to glass fiber, blended as shown in Table 1, and the viscosity of the dispersion medium was shown in Table 1, a fiber-reinforced plastic was produced in the same manner as in Example 8. Sheets for molded bodies, fiber-reinforced plastic molded bodies for measuring the angle of reinforcing fibers and bending strength, and fibers for combustion tests Dimensionally reinforced plastic molded body.

<Example 14>

Regarding Example 2, the addition amount of the anionic high molecular polypropylene amidamine-based thickener was reduced, and the viscosity of the dispersion medium was adjusted as shown in Table 1, so that the attractive forces of the four dehydration tanks provided in the inclined net portion were all the same. Further, except that the pulp-to-mesh speed ratio was adjusted to 0.90, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforcing fiber, and a measurement of the flexural strength were produced in the same manner as in Example 2. And fiber-reinforced plastic moldings for combustion tests.

<Example 15>

(Production of flame retardant-containing polycarbonate resin powder)

The flame retardant-containing polycarbonate resin particles (LN-2520A manufactured by Teijin Ltd.) were freeze-pulverized to obtain a flame retardant-containing polycarbonate resin powder having an average primary particle diameter of 800 μm.

As described in Example 15 of Table 2, the flame retardant-containing polycarbonate fiber was changed to the flame retardant-containing polycarbonate resin powder obtained above, and the pulp-to-speed ratio was adjusted to 0.88. In the same manner as in Example 2, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforced fiber and a measurement of flexural strength, and a fiber-reinforced plastic molded body for a combustion test were produced.

<Example 16>

Except that the pulp-to-web speed ratio was adjusted to 0.51 and the viscosity of the dispersion medium was shown in the table, a sheet for a fiber-reinforced plastic molded body, an angle measurement for reinforcing fibers, and bending were produced in the same manner as in Example 15. Fiber-reinforced plastics for measuring strength Molded bodies and fiber-reinforced plastic molded bodies for combustion tests.

<Comparative example 1>

As described in Comparative Example 1 in Table 3, except that the viscosity of the dispersion medium was adjusted and the pulp-to-web speed ratio was adjusted to 1.3, a sheet for a fiber-reinforced plastic molded body and a reinforced fiber were produced in the same manner as in Example 2. Fiber-reinforced plastic molded bodies for measuring angles and bending strength, and fiber-reinforced plastic molded bodies for combustion tests.

<Comparative example 2>

Except that the viscosity of the dispersion medium was as shown in Table 3 and the pulp-to-speed ratio was adjusted to 3.5, a sheet for a fiber-reinforced plastic molded body, an angle measurement for reinforcing fibers, and A fiber-reinforced plastic molded body for measuring the flexural strength and a fiber-reinforced plastic molded body for a combustion test.

<Comparative example 3>

The flame retardant-containing polycarbonate resin fiber of Comparative Example 1 was changed to a polyetherimide fiber (Kuraray Corporation, fiber diameter: 2.2 dtex × 15 mm), and the viscosity of the dispersion medium was shown in Table 3. Other than that, a sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforcing fiber, and a measurement of flexural strength, and a fiber-reinforced plastic molded body for a combustion test were produced in the same manner as in Comparative Example 1.

<Comparative Example 4>

The carbon fiber of Comparative Example 2 was changed to glass fiber, and the polycarbonate resin fiber containing a flame retardant was changed to polyetherimide fiber, and blended as shown in Table 3, and the viscosity of the dispersion medium was set as shown in Table 3. Except that, it was the same as that of Comparative Example 2 Methods A sheet for a fiber-reinforced plastic molded body, a fiber-reinforced plastic molded body for measuring the angle of the reinforced fiber and a measurement of the bending strength, and a fiber-reinforced plastic molded body for the combustion test were produced.

(Evaluation)

<Measurement of the fiber alignment parameter (fp value) of the reinforcing fibers in the thickness direction>

Examples. The sheet for a fiber-reinforced plastic molded article obtained in the comparative example was cut into a width of 5 mm and a length of 10 mm, and a UV-curable embedding epoxy resin (Aronix LCA D-800, manufactured by Japan Electronics Co., Ltd.) was used with a syringe. ) Impregnation was performed by dripping so as to cover the entire surface of the test piece, and curing was performed by irradiation with ultraviolet rays.

Then, a Slice Master HS-1 manufactured by JASCO Corporation was used to cut a test piece having a width of 0.4 mm and a length of 10 mm from the test piece for cross-section observation. The cutting direction is the BB 'direction in FIG. 1 (b). The BB ′ direction is a direction parallel to the reference line of the planar direction obtained by a method described later.

In addition, the cross section in the thickness direction of the obtained test piece was magnified 300 times with a microscope manufactured by Keynes Corporation, and the reinforcing fibers were observed with transmitted light. Here, a continuous measurement area of 1.5 mm ² in the cross section is observed. The observation surface and the opposite surface of the test piece were focused and observed at a depth of 10 μm or more. Next, for all reinforcing fibers (the number of fibers is n) that are discernible in the observation image in the measurement area, an angle θ _i (i = 1) with respect to a reference line set by a method described later is measured. ~ n). The alignment angle θ _i is an angle measured clockwise with respect to a reference line, and is set to an angle of 0 ° or more and less than 180 °. Then, based on the angle θ _{i of the} fiber with respect to the set reference line, the fiber orientation parameter in the thickness direction is calculated using the following formula (1).

fp = 2 × Σ (cos ² θ _i / n) -1 Equation (1)

The reference line is determined by the following method. When determining the reference line, the hypothetical reference line p is first selected, and the angles of all n reinforcing fibers recognizable in the measurement area are measured. At this time, it is assumed that the angle between the reference line p and each fiber is expressed by α (p) _i (i = 1 to n).

The fiber orientation parameter (fp (p)) of the reinforcing fiber when the reference line p is assumed is calculated using the following formula.

fp (p) = 2 × Σ (cos ² α (p) _i / n) -1

(i = 1, 2, 3, ..., n)

Next, take the hypothetical baseline (p _{+ z} , p _-z (z = 1 ~ 90)) obtained by rotating the hypothetical baseline p in units of ± 1 ° until it becomes ± 90 °, and calculate the hypothetical baseline p _{+ z} and The angle of the n fibers and the angle between the assumed reference line p _-z and the n fibers. The angle at this time is expressed by α (p _{+ z} ) _i and α (p _-z ) _i (i = 1 ~ n).

The assumed reference lines (p _{+ z} , p _-z (z = 1 to 90)) obtained by the rotation, and the fiber alignment parameter (fp (p _{± z} )) of the reinforcing fiber are calculated using the following formula.

fp (p _{± z} ) = 2 × Σ (cos ² α (p _{± z} ) _i / n) -1

(i = 1, 2, 3, ..., n)

In this way, the assumed reference line set when the maximum value is obtained among the obtained absolute values of fp (p) value and fp (p _{± z} ) value is used as the reference line.

<Measurement of the fiber alignment parameter (fp value) of the reinforcing fiber in the plane direction>

Examples. The fiber-reinforced plastic molded article obtained in the comparative example was cut into a width of 3 cm × length of 3 cm, the test piece was sandwiched between glass slides, and one side of the test piece was observed with an optical microscope. The optical microscope was a microscope manufactured by Keynes Corporation, which was magnified up to 300 times to observe the reinforcing fibers with reflected light. Here, a continuous measurement area of 2.0 mm ² in one of the surfaces is observed. Next, for all the reinforcing fibers (the number of fibers is m) that can be discerned in the observation image in the measurement area, an angle θ _i (i = 1 to _i ) with respect to a reference line set by a method described later is measured. m). The alignment angle θ _i is an angle measured clockwise with respect to a reference line, and is set to an angle of 0 ° or more and less than 180 °. Then, based on the angle θ _{i of the} fiber with respect to the set reference line, the fiber orientation parameter in the thickness direction is calculated using the following formula (2).

fp = 2 × Σ (cos ² θ _i / m) -1 Equation (2)

Then, the same measurement was performed for the opposite surface, and the The average value is defined as the fiber orientation parameter (fp) in the plane direction. In addition, the measurement area on one side and the measurement area on the opposite side are areas overlapping in a plan view. In addition, in observation of any of the one side and the opposite side, a part having a depth of 10 μm or more from each of the one side and the opposite side was focused and observed.

The reference line is determined by the following method. When determining the reference line, the hypothetical reference line p is first selected, and the angles of all m reinforcing fibers recognizable in the measurement area are measured. At this time, it is assumed that the angle between the reference line p and each fiber is expressed by α (p) _i (i = 1 to m).

The fiber orientation parameter (fp (p)) when assuming the reference line p is calculated using the following formula.

fp (p) = 2 × Σ (cos ² α (p) _i / m) -1

(i = 1, 2, 3, ..., m)

Next, take the hypothetical baseline (p _{+ z} , p _-z (z = 1 ~ 90)) obtained by rotating the hypothetical baseline p in units of ± 1 ° until it becomes ± 90 °, and calculate the hypothetical baseline p _{+ z} and The angle of m fibers and the angle between the assumed reference line p _-z and the m fibers. The angle at this time is expressed by α (p _{+ z} ) _i and α (p _-z ) _i (i = 1 ~ m).

The assumed reference lines (p _{+ z} , p _-z (z = 1 to 90)) obtained by the rotation, and the fiber alignment parameter (fp (p _{± z} )) of the reinforcing fiber are calculated using the following formula.

fp (p _{± z} ) = 2 × Σ (cos ² α (p _{± z} ) _i / m) -1

(i = 1, 2, 3, ..., m)

In this way, the assumed reference line set when the maximum value is obtained among the obtained absolute values of fp (p) value and fp (p _{± z} ) value is used as the reference line.

<Measurement of angle between reinforcing fiber and fiber-reinforced plastic molded article>

The angle formed between the reinforcing fiber and the center surface of the fiber-reinforced plastic molded article was measured as follows. First, a cross section in the MD direction was cut out of a fiber-reinforced plastic molded body for measuring an angle of a reinforcing fiber obtained in the examples and comparative examples. The three-dimensional measurement X-ray CT device (manufactured by Yamato Scientific Co., Ltd .: trade name "TDM1000-IS / SP") was used to photograph the reinforcing fibers of the profile, and a three-dimensional volume rendering software (Volume Rendering Soft) (manufactured by NVS: "VG-Studio MAX") to obtain an image of the cross section. Then, according to the obtained cross-sectional image, ten 10 μm lines V were arbitrarily drawn along the Z-axis direction, and all fibers that appeared to be in contact with the line were measured as shown by the white line in FIG. 4. Angle formed by the center surface of the plastic molded body. Specifically, a line parallel to the center plane of the fiber-reinforced plastic molded body is represented by a line H (dashed line), and an angle formed by the line H and the reinforcing fiber is measured. The number of fibers to be measured is set to about 100 to 130. Tables 1 to 3 show the ratios of fibers within an angle of ± 20 ° to the center plane of the fiber-reinforced plastic molded body with respect to the total number of fibers measured for the total number of reinforcing fibers.

<Measurement of flexural strength>

The fiber-reinforced plastics for measuring flexural strength obtained in Examples and Comparative Examples The molded product is measured in accordance with the bending test method of JIS K 7074 carbon fiber reinforced plastic in the orientation direction of the fiber (longitudinal direction, hereinafter referred to as MD) and in a direction perpendicular to the orientation of the fiber (lateral direction, hereinafter referred to as CD). The intensity and the intensity ratio in the MD direction and the CD direction are shown in Tables 1 to 3.

Here, FMD represents bending strength in the MD direction, and FCD represents bending strength in the CD direction.

<Evaluation method of flammability>

The molded bodies for the flammability test obtained in the examples and comparative examples were cut into a width of 13 mm and a length of 125 mm to prepare test pieces. The upper end of the test piece was mounted on a holder, and the center of the lower end (edge in the width direction) was brought into contact with a flame having a length of 20 mm for 10 seconds. Then, the flame was removed from the test piece, and the flame was immediately contacted again for 10 seconds after digestion. With or without drips. At this time, absorbent cotton was placed under 12 inches of the fiber-reinforced plastic molded body, and the presence or absence of fire was recorded. Then, the state of drips and absorbent cotton from the test piece was observed, and the flammability was evaluated as follows. In addition, a flame having a length of 20 mm for evaluation is a blue flame having a length of 20 mm specified in UL standard UL94 vertical flammability test.

○: No dripping occurs.

(Triangle | delta): A drip was produced, but a very small amount, and the cotton was not caught.

×: Cotton ignites due to 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 was within a predetermined range, and dripping was unlikely to occur during the flammability test. Furthermore, it can be seen that in Examples 1 to 15, the angle formed by the central surfaces of the reinforcing fibers and the fiber-reinforced plastic molded body was ± 20 °. If it is less than 80%, dripping is less likely to occur during the flammability test. On the other hand, in Comparative Examples 1 to 4, the fp value in the thickness direction in the sheet for a fiber-reinforced plastic molded body was outside the predetermined range, and dripping of the molten thermoplastic resin was observed during the flammability test. Furthermore, in Comparative Examples 1 to 4, the angle formed by the reinforcing fiber and the center plane of the fiber-reinforced plastic molded body was less than 80% within ± 20 °, and dripping of the molten thermoplastic resin was observed during the flammability test.

FIG. 4 shows an image of a cross section of the fiber-reinforced plastic molded article of Example 6 using a three-dimensional measurement X-ray CT apparatus (manufactured by Yamato Scientific Co., Ltd .: "TDM1000-IS / SP"), and based on a three-dimensional volume rendering software (NVS System: "VG-Studio MAX") to confirm the alignment state of the fiber. In addition, the imaging conditions of the three-dimensional measurement X-ray CT device were voltage: 40 kV, tube current: 22 μA, number of pixels: 512 pixels (pixel) × 512 pixels, and field of view size: 2.0 mmΦ × 2.0 mmh.

[Industrial availability]

According to the present invention, it is possible to obtain a fiber-reinforced plastic molded body sheet capable of suppressing the occurrence of dripping matter during the combustion of the fiber-reinforced plastic molded body.

Claims (14)

A sheet for a fiber-reinforced plastic molded body, comprising reinforcing fibers and a thermoplastic resin, characterized in that the thermoplastic resin is a thermoplastic resin having an oxygen limiting index of 30 or more, or the sheet for a fiber-reinforced plastic molded body contains a flame retardant And the absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the fiber-reinforced plastic molded body sheet is 0.5 to 1.0. The sheet for a fiber-reinforced plastic molded body according to item 1 of the scope of application for a patent, wherein when the sheet for a fiber-reinforced plastic molded body contains a flame retardant, the thermoplastic resin is a thermoplastic resin containing a flame retardant. The sheet for a fiber-reinforced plastic molded article according to item 1 of the scope of application, wherein the thermoplastic resin is a thermoplastic resin fiber. The sheet for a fiber-reinforced plastic molded article according to any one of claims 1 to 3, which further contains an adhesive component, and contains a content relative to the total mass of the sheet for a fiber-reinforced plastic molded article. The adhesive component is 0.1 to 10% by mass. The sheet for a fiber-reinforced plastic molded article according to any one of claims 1 to 3, wherein the mass average fiber length of the reinforcing fibers is 6 mm to 100 mm. The sheet for a fiber-reinforced plastic molded article according to any one of claims 1 to 3, wherein when the sheet for a fiber-reinforced plastic molded article contains a flame retardant, the thermoplastic resin is polycarbonate. Ester or polyamide. The sheet for a fiber-reinforced plastic molded article according to any one of claims 1 to 3, wherein the thermoplastic resin having an oxygen limiting index of 30 or more is polyetherimine. A fiber-reinforced plastic molded product obtained by bringing the sheet for a fiber-reinforced plastic molded product according to any one of claims 1 to 7 above the melting point or glass transition temperature of the thermoplastic resin It is formed by pressure-heating and molding at a temperature, and is characterized in that the absolute value of the fiber orientation parameter (fp) of the reinforcing fibers in the thickness direction in the fiber-reinforced plastic molded body is 0.5 to 1.0. The fiber-reinforced plastic molded body according to item 8 of the scope of the patent application has a thickness of 0.4 mm to 1.0 mm. The fiber-reinforced plastic molded body according to item 8 of the scope of the patent application has a geometric mean of bending strength of 200 MPa or more. The fiber-reinforced plastic molded body according to any one of claims 8 to 10 in the scope of the patent application, wherein the fiber-reinforced plastic molded body is formed by heating and pressing at a temperature of 150 ° C to 600 ° C. . A method for manufacturing a sheet for a fiber-reinforced plastic molded body, comprising the step of performing wet papermaking on a slurry obtained by mixing reinforcing fibers with thermoplastic resin fibers, wherein the thermoplastic resin fibers have an oxygen limiting index of 30 or more The thermoplastic resin fiber, or the sheet for a fiber-reinforced plastic molded product contains a flame retardant, and the step of performing the wet papermaking is (A) a step of performing papermaking at a papermaking speed of 5 m / min or more using a cylinder paper machine. Or (B) a step of making paper using a Fourdrinier or inclined papermaking machine, and when the step of performing the wet papermaking includes (B) a step of using a Fourdrinier or inclined papermaking machine to make paper, The net portion of the fourdrinier papermaking machine or the inclined papermaking machine moves so that the pulp-to-web speed ratio becomes 0.95 or less. According to the method for manufacturing a sheet for a fiber-reinforced plastic molded body according to Item 12 of the scope of application, the viscosity at 25 ° C. of the dispersion medium of the slurry exceeds 1.00 mPa and is 4.00 mPa or less. The method for manufacturing a sheet for a fiber-reinforced plastic molded article according to claim 12 or claim 13, wherein the step of performing the wet papermaking is a step of performing papermaking using the inclined papermaking machine.