JP2015217626A - Multilayer molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a multilayer molded article is insufficient in terms of joinability between respective layers, solvent resistance, and mechanical strength.SOLUTION: A multilayer molded article has: a fiber-reinforced plastic molding including a thermoplastic resin and reinforcing fibers; and a resin layer composed of the thermoplastic resin on at least one surface of the fiber-reinforced plastic molding. In the multilayer molded article, the reinforcing fibers are nearly in parallel to the center plane of the fiber-reinforced plastic molding. Furthermore, in the multilayer molded article described in claim 1, the reinforcing fibers penetrate the resin layer and are joined thereto.

Description

  The present invention relates to a multilayer molded article of a fiber reinforced plastic molded body and a resin layer. Specifically, the present invention relates to a multilayer molded article in which the reinforcing fiber is substantially parallel to the center surface of the fiber-reinforced plastic molded body.

  In recent years, structural materials such as aircraft and vehicles, and housing parts of electrical equipment have been required to be lighter, and replacement with molding materials other than metal materials has been promoted. In particular, a fiber-reinforced plastic molded body obtained by heating and pressurizing a nonwoven fabric containing reinforcing fibers such as carbon fibers and glass fibers is used in various fields as an alternative material for metal materials.

  Such a fiber-reinforced plastic molded body is required to have excellent mechanical strength in addition to being lightweight. For this reason, in order to increase the mechanical strength, development of multilayer molded products in which two or more types of plastic layers having different configurations are laminated is underway. For example, Patent Document 1 discloses a two-layer molded article including a core layer formed of a resin composition containing an epoxy compound and a skin layer formed of an acrylic resin. Patent Document 2 discloses a molded article having a non-fiber reinforced plastic layer made of polycarbonate and a fiber reinforced plastic layer containing reinforced fibers and a resin. In Patent Document 2, an epoxy resin is preferably used for the fiber-reinforced plastic layer.

  Further, when molding a multilayer molded article, if the fiber orientation of the reinforcing fiber of the fiber reinforced plastic molded body is random, the fiber reinforced plastic molded body may penetrate the plastic layer on which the reinforcing fiber is laminated. . As a result, for example, when coating is applied to color a multilayer molded article, the solvent of the paint penetrates from the portion of the plastic layer through which the reinforcing fibers penetrate, penetrates into the fiber reinforced plastic molded body, and swells on the surface of the multilayer molded article. There was a problem that occurred.

Japanese Patent Laid-Open No. 11-157018 JP 2009-172950 A

  The laminate-type molded product obtained by the conventional technique has a problem that the bonding property between the layers is not sufficient. In addition, the laminated type molded product obtained by the conventional technique has a problem that the surface of the molded product is swollen, and further, the mechanical strength is not sufficient, and further improvement has been demanded.

  Therefore, in order to solve the problems of the prior art, the present inventors have reduced the swelling of the surface while being lightweight, and have excellent bonding properties between layers and improved mechanical strength. The study proceeded with the aim of providing products.

As a result of intensive studies to solve the above problems, the present inventors have obtained a multilayer molded article having a fiber reinforced plastic molded article and a resin layer, and the reinforcing fiber is a central surface of the fiber reinforced plastic molded article. And almost parallel. From this, it has been found that this multilayer molded article has high resistance to a solvent, high bondability between the respective layers, and high bending strength, and the present invention has been completed.
Specifically, the present invention has the following configuration.
[1] A multilayer molded article having a fiber reinforced plastic molded article including a thermoplastic resin and a reinforced fiber, and a resin layer made of a thermoplastic resin on at least one surface of the fiber reinforced plastic molded article. Is a multilayer molded article characterized by being substantially parallel to the center surface of the fiber-reinforced plastic molded body.
[2] The multilayer molded article according to [1], wherein the reinforcing fiber penetrates and is joined to the resin layer.
[3] The multilayer molded article according to [1] or [2], wherein a thermoplastic resin contained in the fiber-reinforced plastic molded body is different from a thermoplastic resin of the resin layer.
[4] The multilayer molded article according to any one of [1] to [3], wherein the thermoplastic resin contained in the fiber-reinforced plastic molded body is a polyetherimide resin, and the resin layer is a polycarbonate resin.
[5] The multilayer molded article according to any one of [1] to [4], wherein a mass ratio of the resin layer to the multilayer molded article is 5% or more.
[6] A sheet for a multilayer molded article having a fiber reinforced plastic molded sheet containing a thermoplastic resin and reinforcing fibers, and a resin layer made of a thermoplastic resin on at least one surface of the fiber reinforced plastic molded sheet. In the fiber reinforced plastic molded body obtained by heating and pressing the sheet for fiber reinforced plastic molded body, the reinforcing fiber is substantially parallel to the center plane of the fiber reinforced plastic molded body. Sheet for multilayer molded products.
[7] The multilayer molded article according to [6], obtained by heating and pressing the sheet for multilayer molded article.

  According to the present invention, since the fiber orientation of the fiber-reinforced plastic molded body is controlled, there is no reinforcing fiber penetrating the resin layer, preventing the solvent from entering the resin layer, and the surface of the fiber-reinforced plastic molded body Can suppress swelling. Moreover, since the fiber orientation is controlled, the bondability between the fiber-reinforced plastic molded body and the resin layer is increased, and a high bending strength can be obtained. As described above, the multilayer molded article of the present invention is preferably used in various fields such as structural materials for aircrafts and vehicles, and housing parts for electric devices.

FIG. 1 is an image diagram showing the orientation of reinforcing fibers of the fiber-reinforced plastic molded body of the present invention. FIG. 2 shows an image taken with a three-dimensional measurement X-ray CT apparatus (manufactured by Yamato Kagaku Co., Ltd .: trade name “TDM1000-IS / SP”), and with a three-dimensional volume rendering software (manufactured by NVS: “VG-Studio MAX”). It is the image of the obtained cross section. FIG. 3 is a model diagram in the case of measuring the directionality of the reinforcing fibers in the fiber-reinforced plastic molded part of the curved multilayer molded article with a three-dimensional measurement X-ray CT apparatus. (A) is a model diagram of a multilayer molded product having a curved surface shape, and (b) is a model diagram in the case of evaluating the directionality of the reinforcing fiber of the multilayer molded product having a curved surface shape using a three-dimensional measurement X-ray CT apparatus. .

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Multilayer molded product)
One embodiment of the present invention is a multilayer molded article having a fiber reinforced plastic molded article including a thermoplastic resin and reinforcing fibers, and a resin layer made of a thermoplastic resin on at least one surface of the fiber reinforced plastic molded article. . The reinforcing fiber contained in the fiber-reinforced plastic molded body is substantially parallel to the center surface of the fiber-reinforced plastic molded body.

  The “center surface of the fiber-reinforced plastic molded body” is obtained as follows (see FIG. 1). First, the reinforcing fiber orientation direction (B-B ′ line in FIG. 1A) was cut out from the fiber-reinforced plastic molded body (10) after heat and pressure molding. Since the surface of the fiber-reinforced plastic molded body (10) after the heat and pressure molding has an uneven surface as shown in the reinforcing fiber orientation direction (FIG. 1 (b)) when enlarged, the surface average line (30 , 40). The middle line of the surface average lines (30, 40) is the center line (50). Next, another reinforcing fiber orientation direction (C-C ′ line in FIG. 1A) is cut out, and similarly, a surface average line and a center line are obtained. Finally, the center plane of the fiber-reinforced plastic molded body is obtained from the center line of the B-B ′ line section and the center line of the C-C ′ line section.

Further, “substantially parallel to the center plane” means that the angle formed by the center plane of the fiber-reinforced plastic molded body and the reinforcing fibers is oriented within ± 20 °. That is, in the fiber-reinforced plastic molded body of the present invention, 80% or more of the total number of reinforcing fibers is oriented so that the angle formed with the surface of the fiber-reinforced plastic molded body is within ± 20 °. Features.

Thereby, according to one embodiment of the present invention, the fiber orientation is controlled so that the reinforcing fibers of the fiber-reinforced plastic molded body are substantially parallel to the center plane. Does not penetrate. On the other hand, for example, if the reinforcing fibers are oriented in a direction perpendicular to the center plane, the reinforcing fibers may penetrate the resin layer during the formation of the multilayer molded product.
Therefore, in one embodiment of the present invention, for example, when coating a multilayer molded article, the resin layer prevents the solvent contained in the paint from penetrating into the fiber reinforced plastic molded body, and suppresses the swelling of the surface. be able to.

  According to one embodiment of the present invention, since the fiber orientation is controlled so that the reinforcing fibers of the fiber-reinforced plastic molded body are substantially parallel to the center plane, the surface of the fiber-reinforced plastic molded body does not control the fiber orientation. The surface is smoother than that. Therefore, the joint surface between the fiber reinforced plastic molded body and the resin layer becomes large, and the bondability is improved.

  Moreover, according to one Embodiment of this invention, since fiber orientation is controlled so that the reinforced fiber of a fiber reinforced plastic molding becomes substantially parallel to a center surface, it has high bending strength.

  The strength ratio between the bending strength in the first direction and the bending strength in the second direction orthogonal to the first direction of the fiber-reinforced plastic molded body can be adjusted to approximately 3 to 5 or more. In addition, the 1st direction means the orientation direction of the reinforced fiber for fiber reinforced plastic moldings, and the 2nd direction means the direction orthogonal to the orientation direction of a reinforced fiber. Here, the first direction is preferably the MD direction, and the second direction is preferably the CD direction. Thereby, a multilayer molded article having a sufficiently high bending strength in a specific direction can be obtained. In addition, since the reinforcing fibers are oriented in one direction, a multi-layer molded product having a glossy surface and high design properties can be obtained.

  According to one embodiment of the present invention, the reinforcing fibers contained in the fiber-reinforced plastic molded body penetrate into and join a part of the resin layer. Thereby, the bondability of a fiber reinforced plastic molding and a resin layer can be improved.

  According to one embodiment of the present invention, the composition of the thermoplastic resin contained in the fiber-reinforced plastic molded body and the thermoplastic resin of the resin layer are different. When different resins are bonded, the bondability of the bonding surfaces is lowered. However, according to one embodiment of the present invention, the reinforcing fibers included in the fiber-reinforced plastic molded body penetrate into a part of the resin layer, so that the desired resin is bonded. Bondability of the joint surface can be obtained.

  According to one embodiment of the present invention, the thermoplastic resin contained in the fiber-reinforced plastic molded body is a polyetherimide resin, and the resin layer is a polycarbonate resin. Thereby, the characteristics of two kinds of resins can be utilized. For example, since the resin layer is a polycarbonate resin, the bondability with a polycarbonate resin preferably used for outsert molding is enhanced, and the processability of the multilayer molded product is enhanced. Further, since the fiber reinforced plastic molded body is a polyetherimide resin, the flame retardancy of the multilayer molded article is maintained, and a multilayer molded article having processability and flame retardancy can be obtained.

  According to one embodiment of the present invention, the mass ratio of the resin layer to the multilayer molded product is 5% or more. Thereby, the blister which generate | occur | produces by the coating of a multilayer molded product can be prevented.

<Fiber-reinforced plastic molding>
The fiber-reinforced plastic molding can be obtained by heating and pressing a fiber-reinforced plastic molding sheet described later. The sheet for fiber reinforced plastic molded body is singly or laminated to have a desired thickness, and heat-pressed by hot press, or preheated by an infrared heater in advance, and heat-pressed by a mold. be able to. Thus, it can process using the heat press molding method of the general sheet | seat for fiber reinforced plastic moldings.

When molding a fiber reinforced plastic molded body from a fiber reinforced plastic molded body sheet, it is preferable to heat and press mold the fiber reinforced plastic molded body sheet at a temperature equal to or higher than the Vicat softening temperature of the thermoplastic resin fiber. Specifically, it is preferable to heat and press-mold the sheet for fiber-reinforced plastic molded body so that the temperature is Vicat softening temperature −50 ° C. to Vicat softening temperature + 250 ° C. and the pressure is 3 to 40 MPa. The heating temperature is preferably a temperature range in which the thermoplastic resin flows and the reinforcing fibers are not melted.
Below, it describes about the sheet | seat for fiber reinforced plastics molded objects, and its component.

-Sheet for fiber reinforced plastic molding-
The fiber-reinforced plastic molding sheet includes reinforcing fibers and a thermoplastic resin. In addition, you may contain a binder component as needed. And in one Embodiment of this invention, the reinforced fiber is orientated substantially parallel to the center plane of the sheet | seat for fiber reinforced plastic moldings. In addition, since the orientation of the reinforcing fiber of the sheet for fiber-reinforced plastic molded body is substantially the same as the orientation of the reinforcing fiber of the fiber-reinforced plastic molded body, the fiber orientation is evaluated by the fiber-reinforced plastic molded body in the present invention. .

-Reinforcing fiber-
The reinforcing fiber is preferably at least one selected from glass fiber, carbon fiber and aramid fiber. These reinforcing fibers may use only 1 type and may use multiple types. Moreover, you may contain the organic fiber excellent in heat resistance, such as a PBO (polyparaphenylene benzoxazole) fiber.

For example, when inorganic fibers such as carbon fibers and glass fibers are used as the reinforcing fibers, the fiber-reinforced plastic molded body is obtained by heating and pressing at the softening temperature of the thermoplastic resin fibers contained in the fiber-reinforced plastic molded sheet. Can be formed.
In addition, when high heat-resistant and high-strength organic fibers such as aramid fibers are used as reinforcing fibers, a fiber-reinforced plastic molded sheet suitable for precision polishing equipment that requires high smoothness is obtained. be able to. A fiber-reinforced plastic molded article formed from a fiber-reinforced plastic molded sheet containing organic fibers such as aramid as a reinforcing fiber is generally formed from a fiber-reinforced plastic molded sheet using inorganic fibers as the reinforcing fiber. It has better wear resistance than molded products. Moreover, even if a part of the fiber reinforced plastic molded body is scraped off by rubbing or the like, the shaving wrinkles are softer than the inorganic fibers, and therefore there is little risk of damaging the object to be polished.

The fiber length of the reinforcing fiber is preferably 6 to 60 mm, more preferably 8 to 30 mm, and further preferably 10 to 20 mm. By setting the fiber length of the reinforcing fiber within the above range, it is possible to suppress the dropping of the reinforcing fiber from the fiber reinforced plastic molded sheet and to form a fiber reinforced plastic molded article having excellent bending strength. It becomes possible. Moreover, the dispersibility of a reinforced fiber can be made favorable by making the fiber length of a reinforced fiber into the said range. Thereby, the fiber reinforced plastic molding after heat-press molding has high bending strength and appearance.

The fiber diameter of the reinforcing fiber is not particularly limited, but generally, a fiber having a fiber diameter of about 5 to 25 μm is preferably used for both the carbon fiber and the glass fiber.

-Thermoplastic resin-
The thermoplastic resin includes thermoplastic resin fibers. In the present specification, “thermoplastic resin fiber” refers to a fibrous one of thermoplastic resins. The thermoplastic resin may further contain a thermoplastic resin other than the thermoplastic resin fiber. As the thermoplastic resin, powder, pellets, flakes, particles, or fibers can be used. Among these, a fibrous material is preferable from the viewpoint of improving the handling property and yield of the web and from the viewpoint of sufficiently entanglement of the softened thermoplastic resin and the reinforcing fiber to improve the bending strength and rigidity. The thermoplastic resin fiber forms a binding point at the intersection of the thermoplastic resin or the fiber component during the heat and pressure treatment. Compared to a sheet using a thermosetting resin, a sheet for nonwoven fiber-reinforced plastic molded body using such a thermoplastic resin fiber does not require an autoclave treatment, and the heat and pressure molding time for processing is not necessary. Productivity can be increased in a short time.

  The thermoplastic resin fibers include polycarbonate (PC), polyamide, polyolefin (PO), polyether ether ketone (PEEK), polyamide imide (PAI), polyphenylene sulfide (PPS), polyether imide (PEI), polyether ketone ketone. (PEKK) can be exemplified. In addition, as a thermoplastic resin fiber, these fibers may be used independently and these copolymers may be used. Among them, it is preferable to use at least one selected from polycarbonate, polyamide, polyolefin, polyetherimide, and a copolymer thereof from the viewpoint of availability and cost, and obtaining a fiber-reinforced plastic molded body having high bending strength. In particular, it is preferable to use polycarbonate in terms of impact resistance.

  The fiber length of the thermoplastic resin fiber is preferably 2 to 60 mm, more preferably 5 to 40 mm, and still more preferably 10 to 25 mm. By setting the fiber length of the thermoplastic resin fiber within the above range, the thermoplastic resin fiber can be prevented from falling off from the fiber reinforced plastic molded sheet, and the fiber reinforced plastic molded article having excellent handling properties. A sheet can be obtained. In addition, by making the fiber length of the thermoplastic resin fiber within the above range, it is possible to improve the dispersibility of the thermoplastic resin fiber, so it is possible to form a fiber-reinforced plastic molded article with excellent bending strength. It becomes. Thereby, the fiber reinforced plastic molding after heat-press molding has the appearance which was excellent in high bending strength and design nature.

The thermoplastic resin fibers are preferably chopped strands cut to a certain length. With such a form, the thermoplastic resin fibers can be uniformly mixed in the fiber-reinforced plastic molded sheet. Moreover, the cross-sectional shape of the fiber is not limited to a circular shape, and an elliptical shape or a modified cross-sectional shape can also be used.

-Mixing ratio of reinforcing fiber and thermoplastic resin-
In the sheet for fiber-reinforced plastic molded body of the present invention, the mass ratio of the reinforcing fiber and the thermoplastic resin fiber is preferably 10:90 to 80:20, more preferably 20:80 to 70:30, More preferably, it is 30: 70-70: 30. By setting the mass ratio of the reinforcing fiber and the thermoplastic resin fiber within the above range, it is possible to obtain a fiber-reinforced plastic molded body that is lightweight and has high bending strength.

-Binder component-
The binder component has a function of binding the fibers and suppressing the dropping of the fibers. In this invention, as a binder contained in the sheet | seat for fiber reinforced plastic molded objects, the acrylic resin generally used for nonwoven fabric manufacture, a styrene-acrylic resin, a polyester resin, a modified polyester resin, a polyethylene resin, a polypropylene resin, EVA Resin, urethane resin, PVA resin, etc. can be used. In addition, these binder components may be used individually by 1 type, and may be used in combination of 2 or more types.
In addition, these resins can be made into fiber or particle form, mixed with the above-mentioned reinforcing fiber / thermoplastic resin fiber, and wet-paper-made, or made into an emulsion or aqueous solution and applied to the web by spraying or impregnation. You can also
Among these, the binder component is particularly preferably a resin component that is compatible with the resin when the thermoplastic resin is softened by heat and pressure molding. When such a resin component is used as a binder, there is no interface between the thermoplastic resin and the binder resin after the heat and pressure molding, and the flexural strength is high because they are integrated. Furthermore, it has the characteristic that there is little fall of the Vicat softening temperature of the thermoplastic resin resulting from a binder component.

-Fiber shape-
The thermoplastic resin fiber, the reinforcing fiber, and the binder fiber used in the present invention are preferably chopped strands cut to a certain length. Moreover, the cross-sectional shape of the fiber is not limited to a circular shape, and an elliptical shape or a modified cross-sectional shape can also be used. By setting it as such a form, various fibers can be mixed uniformly in the sheet | seat for fiber reinforced plastic moldings. Moreover, the production efficiency of the multilayer molded product can be increased.

<Resin layer>
The resin layer includes a thermoplastic resin. There is no restriction | limiting in particular as a thermoplastic resin used for a resin layer. Examples of the thermoplastic resin used for the resin layer are the same as those of the thermoplastic resin of the thermoplastic resin fiber used as the thermoplastic resin of the fiber-reinforced plastic molded body. In addition, as a thermoplastic resin used for a resin layer, these thermoplastic resins may be used independently and these copolymers may be used. Among these, from the viewpoint of availability and cost, it is preferable to use at least one selected from polycarbonate, polyamide, polyolefin, polyetherimide and copolymers thereof, and in particular, polycarbonate is used in terms of impact resistance. Is preferred. The resin layer of the present invention is molded by any molding method used for the production of ordinary plastics, for example, injection molding, hollow molding, extrusion molding, vacuum molding and the like. Alternatively, a thermoplastic resin may be made into a fiber and formed into a sheet by a dry nonwoven fabric method or a wet nonwoven fabric method, followed by hot press molding. Furthermore, a commercially available thermoplastic resin film, woven fabric, or knitted fabric may be used.

(Sheet for multilayer molded products)
A sheet for a multilayer molded article having a resin layer made of a thermoplastic resin on at least one surface of a sheet for a fiber reinforced plastic molded article containing a thermoplastic resin fiber and a reinforcing fiber, and a sheet for a fiber reinforced plastic molded article, In the fiber-reinforced plastic molded body obtained by heating and pressing the sheet for fiber-reinforced plastic molded body, the reinforcing fiber is substantially parallel to the center plane of the fiber-reinforced plastic molded body.

(Manufacturing method of multilayer molded product)
-Manufacturing method of sheet for fiber reinforced plastic molding-
The process for producing the sheet for fiber-reinforced plastic molded body of the present invention comprises the steps of mixing a reinforcing fiber, a thermoplastic resin containing thermoplastic resin fibers, and a binder component as necessary, and a fiber-reinforced plastic molded body by a wet nonwoven fabric method. A process for producing a sheet for use.

Moreover, it is preferable that the method of manufacturing the sheet | seat for fiber reinforced plastic moldings of this invention is a wet nonwoven fabric method which removes a solvent from the fiber slurry which disperse | distributed the fiber in the solvent, and manufactures a web. Hereinafter, preferable conditions of the wet nonwoven fabric method will be described.
When paper making is performed by a wet nonwoven fabric method using a circular paper machine, the diameter of the circular mesh of the circular paper machine is preferably 50 cm or more. By setting the diameter of the circular net of the circular net paper machine within the above range, it is possible to orient 80% or more reinforcing fibers so as to be substantially parallel to the center plane of the fiber-reinforced plastic molded body.

  The paper making speed in the case of making paper using a circular paper machine is preferably 3 m / min or more, more preferably 5 m / min or more, and further preferably 10 m / min or more. By setting the paper making speed within the above range, 80% or more of the reinforcing fibers can be oriented so as to be substantially parallel to the center plane of the fiber-reinforced plastic molded body.

Moreover, in the process of manufacturing the sheet | seat for fiber reinforced plastic moldings, you may use a long net paper machine or an inclined wire paper machine other than a circular net paper machine. That is, in the process for producing a sheet for fiber-reinforced plastic molded article of the present invention, the process for producing a sheet for fiber-reinforced plastic molded article includes a step of making a paper using a long net paper machine or an inclined wire paper machine. May be. Here, in the step of making paper using a long paper machine or an inclined wire paper machine, it is preferable that the wire of the long paper machine or the inclined wire paper machine runs so that the jet wire ratio is 0.98 or less. .
Here, the jet wire ratio is the ratio of the flow rate in the fiber slurry liquid inlet to the wire travel speed, and is represented by the flow rate in the fiber slurry liquid inlet / wire travel speed. In an inclined wire paper machine, in general, the flow rate of the fiber slurry is adjusted by adjusting the white water circulation rate. When the jet wire ratio is larger than 1, the supply speed of the fiber slurry is faster than the traveling speed of the wire, and this case is referred to as “pressing formation”. When the jet wire ratio is smaller than 1, the fiber slurry liquid supply speed is slower than the wire traveling speed, and this case is referred to as “pulling”.
The state where the above-described jet wire ratio is 0.98 or less is the case of “pull-in”. In such a case, the angle formed by the center surface of the fiber-reinforced plastic molded body and the reinforcing fiber can be oriented within ± 20 °.
In addition, it is preferable that the process of manufacturing the sheet | seat for fiber reinforced plastic moldings includes the process of making paper using a long net paper machine or an inclined wire paper machine, and includes the process of making paper using an inclined wire paper machine. Is more preferable from the viewpoint of fiber dispersibility.

In one embodiment of the present invention, by adjusting the jet wire ratio in the manufacturing method, the fibers can be oriented in a specific direction, and the bending strength in that direction can be further increased. In order to orient the fibers in a specific direction, the jet wire ratio may be reduced. That is, by setting the jet wire ratio to 0.75 or less, the strength ratio of the bending strength in the MD direction and the bending strength in the CD direction of the fiber-reinforced plastic molded body can be adjusted to approximately 3 to 5 or more. . Thus, in the production method of the present invention, by setting the jet wire ratio in the above range, the reinforcing fibers can be oriented in a specific direction, and the bending strength and impact resistance in the specific direction can be further increased.
When the jet wire ratio is reduced in this way, in the inclined wire paper machine, the paper making condition is usually adjusted to increase the paper making speed while reducing the flow rate in the inlet by reducing the white water circulation rate. . In this case, if the amount of white water circulation is too small, the fiber dispersibility in the inlet tends to deteriorate, but by increasing the liquid level in the inlet as much as possible, the flow rate can be increased while maintaining the white water circulation amount. It is possible to slow down and reduce the jet wire ratio.

  Furthermore, it is preferable that the process for producing a fiber-reinforced plastic molded sheet includes a process of internally adding, applying or impregnating a nonwoven fabric sheet with a solution containing a binder component or an emulsion containing a binder component, followed by heating and drying. That is, the process for producing a sheet for fiber reinforced plastic molded body includes a process for producing a sheet for fiber reinforced plastic molded body by a wet nonwoven fabric method, and a process for internally adding, applying or impregnating a nonwoven fabric sheet with a solution containing a binder component. It is preferable to contain. Further, after the internal addition, coating or impregnation, a step of drying by heating is included. By providing such a process, it is possible to suppress scattering, fluffing and dropping off of the surface fibers of the fiber reinforced plastic molded sheet, and to obtain a fiber reinforced plastic molded sheet having excellent handling properties.

In one embodiment of the present invention, a sheet for multilayer molded articles is obtained by heating and pressing. This
Since the sheet density of the fiber reinforced plastic molded sheet is heated and pressed in a low state, the resin layer on the surface of the fiber reinforced plastic molded sheet penetrates into and joins the fiber reinforced plastic molded sheet, so that the bondability Becomes higher.

The heating and pressing conditions are not particularly limited as long as the thermoplastic resin can be slightly dissolved or fluidized and bonded. For example, when polycarbonate is included as a thermoplastic resin, it is preferably lightly pressed in the range of 150 to 200 ° C.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

Example 1
Carbon fiber (“HTC110” manufactured by Toho Tenax Co., Ltd., cut length: 13 mm) was introduced into water, and the product name “Emanon 3199” (manufactured by Kao Co., Ltd.) dissolved in advance to a concentration of 0.6% by mass as a dispersant was obtained. It added so that it might become 1.0 mass% with respect to carbon fiber as solid content addition amount, Furthermore, it diluted so that carbon fiber slurry density | concentration might be 0.5 mass% by adding water. Further, the slurry was stirred with a pulper for 3 minutes to disperse the carbon fibers.
The obtained carbon fiber slurry was sent to another container, polycarbonate resin fibers (manufactured by Daiwabo Polytex Co., Ltd., fiber diameter 30 μm, fiber length 12 mm), and fibrous PVA (manufactured by Kuraray Co., Ltd.) as a binder. “VPB-105-2”) was weighed and added so as to have the following mass ratio.
Carbon fiber / polycarbonate fiber / fibrous PVA = 45/53/2
Furthermore, water was added to this slurry so that the fiber slurry concentration would be 0.5%, and stirred to mix and disperse the fibers.

This fiber slurry was continuously fed to an inclined wire machine (inclined paper machine) to form a wet web. Then, the sheet | seat for fiber reinforced plastic moldings with a basic weight of 235g / m < ² > was obtained by making it heat-dry at 140 degreeC using the Yankee dryer and hot-air dryer with which the said paper machine was equipped. In addition, when the fiber slurry is fed to the inclined wire machine to form a wet web, an aqueous solution of an anionic polyacrylamide-based thickener “Sumifloc” (manufactured by MT Aqua Polymer Co., Ltd.) is appropriately added, and the slurry viscosity is 1 cps to Papermaking was carried out while adjusting in the range of 5 cps (B-type viscometer measurement). Moreover, by controlling the white water circulation flow rate and the paper making speed, the jet wire ratio was adjusted to 0.98 to make paper.
Two sheets of each fiber reinforced plastic molded body obtained were stacked, and a polycarbonate film (manufactured by Toray Industries, Inc.) having a thickness of 100 μm (weighing 120 g / m ² ) was further laminated as a resin layer. The laminate was sandwiched between 2 mm thick stainless steel plates, and a stainless plate of 590 μm thickness × 15 mm width × 200 mm length was arranged as a spacer on both sides of the laminate product. And by heating and pressing at 220 ° C. and 10 MPa for 5 minutes and cooling to 70 ° C. while applying 10 MPa, the thickness is 590 μm and the mass ratio of the polycarbonate resin layer to the multilayer molded product is 20%. A multilayer molded article having a density of 1.00 g / cm ³ was obtained.
The stainless steel plate having a thickness of 2 mm is obtained by applying Frecote FC55 (manufactured by HENKEL) as a release agent after surface finishing in accordance with JIS G4305 # 400.

(Example 2)
A multilayer having a density of 1.00 g / cm ³ in the same manner as in Example 1 except that the carbon fiber is changed to glass fiber (“CS13-JAJP195” manufactured by Owens Corning, fiber length 13 mm, fiber diameter 10 μm). A molded product was obtained.

(Example 3)
The density is 1.00 g / cm ^{3 in the same} manner as in Example 1 except that the polycarbonate fiber is changed to a polyetherimide fiber (2.2 dtex × 12 mm manufactured by Kuraray Co., Ltd.) and the heating and pressing temperature is changed to 300 ° C. A multilayer molded product was obtained.

Example 4
A multilayer molded article having a density of 1.00 g / cm ³ was obtained in the same manner as in Example 3 except that the fiber orientation in the MD direction was increased by changing the jet wire ratio at the time of papermaking to 0.5. Obtained.

(Example 5)
By changing the thickness of the polycarbonate film used as the resin layer to 38 μm (weight per unit: 45.6 g / m ² ), the mass ratio of the polycarbonate resin layer to the multilayer molded product is 8.8%, and the spacer thickness is changed to 516 μm. Thus, a multilayer molded product having a density of 1.00 g / cm ³ was obtained in the same manner as in Example 3 except that the thickness of the multilayer molded product was 516 μm.

(Example 6)
By changing the thickness of the polycarbonate film to be the resin layer to 11 μm (weight per unit: 13.2 g / m ² ), the mass ratio of the polycarbonate resin layer to the multilayer molded product is 2.7%, and the spacer thickness is changed to 483 μm. Thus, a multilayer molded product having a density of 1.00 g / cm ³ was obtained in the same manner as in Example 3 except that the thickness of the multilayer molded product was changed to 483 μm.

(Comparative Example 1)
Except that the polycarbonate film is not laminated at the time of heat and pressure molding, two sheets for fiber reinforced plastic molded products are stacked, and the thickness of the multilayer molded product is changed to 470 μm by changing the spacer thickness to 470 μm. In the same manner as in Example 1, a multilayer molded article having a density of 1.00 g / cm ³ was obtained.

(Comparative Example 2)
Carbon fiber (“HTC110” manufactured by Toho Tenax Co., Ltd., cut length 13 mm), polycarbonate (PC) resin fiber (manufactured by Daiwabo Polytex Co., Ltd., fiber diameter 30 μm, fiber length 12 mm), and fibrous PVA (manufactured by Kuraray Co., Ltd.) Using VPB-105-2 "), a sheet for fiber-reinforced plastic molded product having a basis weight of 235 g / m ² having a raw material mixing ratio of the following mass ratio was produced by the airlaid method.
Carbon fiber / polycarbonate fiber / fibrous PVA = 45/53/2
The obtained sheet for plastic molded article was subjected to heat and pressure treatment in the same manner as in Example 1 to obtain a multilayer molded article having a density of 1.00 g / cm ³ .

(Comparative Example 3)
In Example 3, when obtaining the sheet | seat for fiber reinforced plastics molded articles, carbon fiber is not used but polyetherimide fiber and fibrous PVA were changed so that it might become the following mass ratio, and Example 3 and Similarly, a multilayer molded product was obtained.
Polycarbonate fiber / fibrous PVA = 98/2

[Evaluation]
(Measurement of fiber orientation)
Fiber orientation was performed by evaluating the directionality of the reinforcing fiber as follows.
First, a cross section in the MD direction (BB ′ line in FIG. 1A) was cut out from the fiber-reinforced plastic molded body after heat and pressure molding. An image of a cross section in the MD direction is shown in FIG. The cross-sectional reinforcing fiber was photographed with a three-dimensional measurement X-ray CT apparatus (trade name “TDM1000-IS / SP” manufactured by Yamato Kagaku Co., Ltd.), and three-dimensional volume rendering software (manufactured by NVS: “VG-Studio MAX”). ) To obtain a cross-sectional image. Then, about the obtained cross-sectional image, arbitrarily draw ten 10 μm line ridges in the Z-axis direction, and line H (dotted line) drawn perpendicular to the line V and reinforcing fibers for all the fibers that are in contact with the line. The angle formed by was measured. The number of fibers measured was about 100 to 130. Table 1 shows the ratio of the number of fibers occupied by fibers whose angle formed with the fiber-reinforced plastic molded body is within ± 20 ° with respect to the total number of measured reinforcing fibers. The larger this ratio, the more fiber blending is parallel to the fiber-reinforced plastic molded body.
In FIG. 1B, θ ₁ is an angle between the reinforcing fiber and the fiber-reinforced plastic molded body within ± 20 °, and θ ₂ is an angle between the reinforcing fiber and the fiber-reinforced plastic molded body is ± 20. ° is out of range.
The number ratio of fibers having an angle of 20 ° or less is defined as fiber orientation and is shown in Table 1.
In addition, according to this method, as shown in FIG. 2, fiber orientation can be evaluated in the range of about 50 to 100 μm in the XY direction.
As shown in FIG. 3, even if the multilayer molded product is processed into a curved surface shape, it is difficult to process a curved surface in such a narrow range. Also, the fiber orientation of the multilayer molded product can be appropriately evaluated.

(Measurement of bending strength)
In accordance with JIS K7074 “Bending test method for carbon fiber reinforced plastic”, the obtained multilayer molded article was subjected to fiber orientation direction (machine direction, hereinafter referred to as MD) and fiber orientation and perpendicular direction (cross direction, hereinafter referred to as CD). Measured). Table 1 shows the bending strength in the MD direction and the CD direction, the bending strength ratio in the MD direction and the CD direction, and the geometric mean value of the bending strength obtained by the following formula.
The geometric mean value of bending strength = √ (MD direction strength × CD direction strength)

(Evaluation of swelling)
0.05 g of toluene was dropped onto the surface of the obtained multilayer molded article using a dropper, and wiped off after 3 seconds. And, A where the swelling of the toluene dripping part is not observed at all is A, the swelling is slightly confirmed but the boundary of the swelling generating part is not clear and the diameter cannot be measured, B, the swelling is clearly observed and measured with a caliper Those having a diameter of 20 mm or more were evaluated as C and are shown in Table 1.

(Jointability of joint surface)
JAPAN TAPPI No. In the measurement piece after measuring the tensile strength in the Z-axis direction of the multilayer molded product by a method in accordance with No. 18, the entire peeled surface was A in which fracture occurred in the fiber reinforced plastic molded body layer, 90% of the peeled surface The above was evaluated as B when peeling occurred in the fiber reinforced plastic molded body layer, and as C when the joint surface between the fiber reinforced plastic molded body and the resin layer peeled over the entire peeled surface.
This method is a method in which two metal blocks are bonded to both surfaces of a multilayer molded product with a double-sided adhesive tape, the metal blocks are attached to a tensile tester, and a tensile test is performed. When the joining property of the joining surface is high, the resin layer does not peel off, so that the fiber-reinforced plastic molded body layer is broken and broken. When the joining property of the joining surface is low, the joining surface peels off.

As shown in Table 1, all the multilayer molded articles according to the present invention do not cause swelling of the toluene dropping portion, and the joining property of the joining surface is high. Moreover, the joining property of a joining surface is also high. Further, in Example 4 in which the jet wire ratio is set to 0.5, the bending strength in the MD direction is particularly increased.
On the other hand, in Comparative Example 1 having no resin layer, the swelling of the toluene dropping portion is severe.
Further, in Comparative Example 2 where the number of fibers whose fiber orientation measured by the above-described method is within 20 ° is small and the number of fibers that are not parallel to the fiber-reinforced plastic molded article is large, the swelled portion of the toluene dripping portion is similarly expanded. Intense.
Furthermore, in Comparative Example 3 containing no reinforcing fiber, the bending strength was low, and the peel strength between the resin layer and the plastic molded body layer was very weak, which was not practical.

  According to the present invention, since the fiber orientation of the fiber-reinforced plastic molded body is controlled, there is no reinforcing fiber penetrating the resin layer, preventing the solvent from entering the resin layer, and the surface of the fiber-reinforced plastic molded body Can suppress swelling. Moreover, since the fiber orientation is controlled, the bondability between the fiber-reinforced plastic molded body and the resin layer is increased, and a high bending strength can be obtained. As described above, the multilayer molded article of the present invention is preferably used in various fields such as structural materials for aircrafts and vehicles, and housing parts for electric devices.

DESCRIPTION OF SYMBOLS 10 Fiber reinforced plastic molding 20 Reinforcing fiber 30, 40 Surface average line 50 Center line

Claims (7)

A fiber-reinforced plastic molded article containing a thermoplastic resin and reinforcing fibers;
A multilayer molded article having a resin layer made of a thermoplastic resin on at least one surface of the fiber-reinforced plastic molded body,
The multilayer molded article, wherein the reinforcing fiber is substantially parallel to a center surface of the fiber-reinforced plastic molded body.   The multilayer molded article according to claim 1, wherein the reinforcing fiber penetrates and is joined to the resin layer.   The multilayer molded article according to claim 1 or 2, wherein the thermoplastic resin contained in the fiber-reinforced plastic molded body is different from the thermoplastic resin of the resin layer. The multilayer molded article according to any one of claims 1 to 3, wherein the thermoplastic resin contained in the fiber-reinforced plastic molded body is a polyetherimide resin, and the resin layer is a polycarbonate resin. The multilayer molded article according to any one of claims 1 to 4, wherein a mass ratio of the resin layer to the multilayer molded article is 5% or more. A sheet for a fiber-reinforced plastic molded article containing a thermoplastic resin and reinforcing fibers;
A sheet for multilayer molded articles having a resin layer made of a thermoplastic resin on at least one surface of the sheet for fiber-reinforced plastic molded article,
In the fiber reinforced plastic molded body obtained by heating and pressing the sheet for fiber reinforced plastic molded body, the multilayered molded product is characterized in that the reinforcing fiber is substantially parallel to the center surface of the fiber reinforced plastic molded body. Sheet. The multilayer molded article according to claim 6, which is obtained by heating and pressing the sheet for multilayer molded article.

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