JP7527993B2 - Composite laminate and method for producing same - Google Patents

Description

The present invention relates to a fiber-reinforced composite laminate and a method for manufacturing the composite laminate.

Fiber-reinforced resins are light and strong, and are used as an alternative to metals in a variety of fields, including golf clubs, tennis rackets, aircraft, and automobiles. In recent years, fiber-reinforced resins have been attracting attention in the automotive field due to the need to reduce the weight of automobiles in order to achieve low fuel consumption. However, there are various issues to be addressed when using fiber-reinforced resins in automotive components. For example, fiber-reinforced resins made of thermosetting resins require heat treatment (curing reaction) after molding, and therefore cannot achieve the high productivity and low cost required for the manufacture of automotive components. Therefore, there is a demand for fiber-reinforced thermoplastic resins (hereinafter also referred to as "FRTP") that use thermoplastic resins that are easy to mold instead of thermosetting resins.

Typical forms of FRTP include molded products in which a sheet impregnated with a thermoplastic resin is laminated onto a reinforced fiber substrate in which continuous reinforcing fibers are aligned in one direction, or a reinforced fiber substrate in which continuous reinforcing fibers are woven, and then shaped into the desired shape by heating and pressurizing using a press or the like. The molded products obtained in this way can be designed with excellent mechanical properties because they use continuous reinforcing fibers, and the variation in mechanical properties is small. However, because they use continuous reinforcing fibers, it is difficult to form complex shapes such as three-dimensional shapes, and they are mainly limited to components with roughly flat shapes.

Therefore, FRTP using discontinuous reinforcing fibers has been proposed. For example, Patent Document 1 proposes a prepreg (a sheet-shaped molding intermediate material in which continuous or discontinuous reinforcing fibers are impregnated with a thermoplastic resin is sometimes called a prepreg) that contains two types of discontinuous reinforcing fibers with different lengths and a thermoplastic resin. Patent Document 2 also proposes the use of a prepreg made of a nonwoven fabric that contains discontinuous reinforcing fibers and discontinuous thermoplastic resin fibers.

JP 2010-235779 A JP 2018-095716 A

However, molded products using discontinuous reinforcing fibers such as those in Patent Documents 1 and 2 have the problem that they have poorer mechanical properties than molded products using continuous reinforcing fibers. In addition, there is a problem that voids are easily generated due to gaps between the reinforcing fibers, which also easily leads to a decrease in mechanical properties.

The object of the present invention is to provide a composite laminate having excellent mechanical properties and a method for producing the composite laminate.

The present invention provides the following composite laminate and its manufacturing method.

Item 1: A composite laminate containing reinforcing fibers and a thermoplastic resin, the composite laminate being formed by integrating a laminate containing a film (A) and a sheet (B) by thermocompression bonding, the laminate having a portion in which the film (A) is laminated between a plurality of the sheets (B) so as to be in direct contact with the sheet (B), the film (A) containing a reinforcing fiber (a1) having an average fiber length of 1 μm or more and less than 100 μm, which is at least one of potassium titanate fiber and wollastonite fiber, and a thermoplastic resin (a2), the sheet (B) containing a reinforcing fiber (b1) having an average fiber length of 1 mm or more, and a thermoplastic resin (b2), the ratio of the average fiber length of the reinforcing fiber (a1) to the average fiber diameter of the reinforcing fiber (b1) (average fiber length of (a1)/average fiber diameter of (b1)) being more than 1 and not more than 10.

Item 2: The composite laminate according to item 1, characterized in that the mass ratio ((a1)/(b1)) of the reinforcing fiber (a1) to the reinforcing fiber (b1) in the entire laminate is 0.01 or more and 1 or less.

Item 3: The composite laminate according to item 1 or 2, characterized in that the thermoplastic resin (a2) is at least one selected from the group consisting of polyolefin resins, polystyrene-based resins, polyester-based resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyether sulfone resins, polyether aromatic ketone resins, polyether imide resins, and thermoplastic polyimide resins.

Item 4: The composite laminate according to any one of items 1 to 3, characterized in that the content of the reinforcing fiber (a1) is 0.5% by mass or more and 35% by mass or less, based on 100% by mass of the total amount of the components contained in the film (A).

Item 5: The composite laminate according to any one of items 1 to 4, characterized in that the film (A) further contains spherical particles (a3).

Item 6: The composite laminate according to any one of items 1 to 5, characterized in that the reinforcing fiber (b1) is at least one type selected from the group consisting of carbon fiber, glass fiber, and aramid fiber.

Item 7: The composite laminate according to any one of items 1 to 6, characterized in that the content of the reinforcing fiber (b1) is 10% by mass or more and 80% by mass or less, based on 100% by mass of the total amount of the components contained in the sheet (B).

Item 8: The composite laminate according to any one of items 1 to 7, characterized in that the thermoplastic resin (b2) is at least one selected from the group consisting of polyolefin resins, polystyrene-based resins, polyester-based resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyether sulfone resins, polyether aromatic ketone resins, polyetherimide resins, and thermoplastic polyimide resins.

Item 9: The composite laminate according to any one of items 1 to 8, wherein the film (A) is further provided on at least one of the outermost layers on both sides of the laminate.

Item 10: The composite laminate according to any one of items 1 to 9, wherein the laminate has a portion in which the sheet (B) is laminated between a plurality of the films (A) so as to be in direct contact with the film (A).

Item 11. The composite laminate according to any one of items 1 to 10, which is used as an automobile component or an electric/electronic device component.

Item 12: A method for producing a composite laminate containing reinforcing fibers and a thermoplastic resin, comprising: a step (I) of preparing a laminate by stacking a film (A) containing reinforcing fibers (a1) having an average fiber length of 1 μm or more and less than 100 μm, which are at least one of potassium titanate fibers and wollastonite fibers, and a thermoplastic resin (a2); and a step (II) of integrating the laminate by thermocompression to obtain a composite laminate, wherein in the step (I), the film (A) has a portion stacked between a plurality of the sheets (B) so as to be in direct contact with the sheet (B), and the laminate is prepared so that the ratio of the average fiber length of the reinforcing fibers (a1) to the average fiber diameter of the reinforcing fibers (b1) (average fiber length of (a1)/average fiber diameter of (b1)) is more than 1 and 10 or less.

The present invention provides a composite laminate and a method for producing a composite laminate that has excellent mechanical properties.

FIG. 1 is a schematic cross-sectional view showing laminates constituting a composite laminate according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing laminates constituting a composite laminate according to a second embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing laminates constituting a composite laminate according to a third embodiment of the present invention.

The following describes preferred embodiments. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in the drawings, components having substantially the same functions may be referred to by the same reference numerals.

The composite laminate of the present invention contains reinforcing fibers and a thermoplastic resin. The composite laminate of the present invention is formed by integrating a laminate including a film (A) and a sheet (B) by thermocompression bonding. The laminate has a portion in which the film (A) is laminated between a plurality of sheets (B) so as to be in direct contact with the sheet (B).

The film (A) contains reinforcing fibers (a1) and a thermoplastic resin (a2). The reinforcing fibers (a1) have an average fiber length of 1 μm or more and less than 100 μm, and are at least one of potassium titanate fibers and wollastonite fibers.

The sheet (B) contains reinforcing fibers (b1) and a thermoplastic resin (b2). The reinforcing fibers (b1) have an average fiber length of 1 mm or more.

In addition, in the present invention, the ratio of the average fiber length of reinforcing fiber (a1) to the average fiber diameter of reinforcing fiber (b1) (average fiber length of (a1)/average fiber diameter of (b1)) is more than 1 and 10 or less.

The composite laminate of the present invention has the above-mentioned configuration and therefore has excellent mechanical properties. This can be explained as follows.

In the present invention, the sheet (B) and the film (A) directly laminated between the sheets (B) are integrated by thermocompression bonding, so that a part or all of the constituent materials of the film (A) are mixed with the sheet (B), and the reinforcing fibers (a1), which are microfibers, are thought to fill the gaps between the reinforcing fibers (b1). In this case, if the ratio of the average fiber diameter of the reinforcing fibers (b1) to the average fiber length of the reinforcing fibers (a1) is within the above range, the mechanical properties of the composite laminate can be improved without reducing the reinforcing effect of the reinforcing fibers (b1). It can also be expected that voids will be less likely to occur and that moldability will be improved.

In general, a "sheet" is defined in the JIS as a thin, flat product whose thickness is generally small relative to its length and width, and a "film" is generally a thin, flat product whose thickness is extremely small compared to its length and width, and whose maximum thickness is arbitrarily limited, and which is usually supplied in the form of a roll (Japanese Industrial Standards JIS K6900). For example, in terms of thickness, in the narrow sense, a product with a thickness of 100 μm or more is called a sheet, and a product with a thickness of less than 100 μm is sometimes called a film. However, the boundary between a sheet and a film is unclear, and there is no need to distinguish between the two in the present invention, so in the present invention, when a product is called a "sheet," it is also considered to include a "film," and when a product is called a "film," it is also considered to include a "sheet."

An example of a laminate that constitutes the composite laminate of the present invention is described below.

Figure 1 is a schematic cross-sectional view showing the laminates constituting the composite laminate according to the first embodiment of the present invention.

As shown in FIG. 1, the laminate 1 includes a film (A) and a sheet (B). Such a laminate 1 can be integrated by thermocompression bonding and used as a composite laminate.

In the first embodiment, the laminate 1 is composed of four layers of film (A) and eleven layers of sheet (B). Specifically, the sheet (B) is provided in the central portion 2 of the laminate 1. The sheet (B) in the central portion 2 has a first main surface 2a and a second main surface 2b that face each other. On the first main surface 2a of the sheet (B) in the central portion 2, one layer of film (A), five layers of sheet (B), and one layer of film (A) are provided in this order. On the second main surface 2b of the sheet (B) in the central portion 2, one layer of film (A), five layers of sheet (B), and one layer of film (A) are provided in this order. Thus, in the laminate 1, the film (A) is provided on the outermost layers 3 and 4 on both sides.

As in the laminate 21 of the second embodiment shown in FIG. 2, the film (A) may be provided only on one of the outermost layers 3, 4 on both sides, or as in the laminate 31 of the third embodiment shown in FIG. 3, the film (A) may not be provided on both of the outermost layers 3, 4 on both sides. However, in the present invention, it is preferable that the film (A) is provided on at least one of the outermost layers 3, 4 on both sides, and it is more preferable that the film (A) is provided on both of the outermost layers 3, 4 on both sides. In this case, burrs are less likely to occur on the cut cross section during cutting of the composite laminate, and cutting workability can be further improved.

Also, as in the laminate 31 of the third embodiment shown in FIG. 3, only one layer of film (A) may be provided inside the laminate 31. Specifically, the film (A) may have a portion that is laminated between multiple sheets (B) so as to be in direct contact with the sheet (B). This can improve the mechanical properties of the composite laminate as described above. However, in the present invention, as in the first embodiment, it is preferable that the sheet (B) also has a portion that is laminated between multiple films (A) so as to be in direct contact with the film (A). In this case, the mechanical properties of the composite laminate can be further improved.

In the present invention, the number of layers in the entire laminate is not particularly limited, but is preferably 5 layers or more, more preferably 12 layers or more, and preferably 30 layers or less, more preferably 18 layers or less. When the number of layers in the laminate is within the above range, the mechanical properties of the composite laminate can be further improved.

The number of films (A) contained in the laminate is not particularly limited, but is preferably 1 or more, more preferably 2 or more, and preferably 10 or less, more preferably 5 or less. When the number of films (A) contained in the laminate is within the above range, the mechanical properties of the composite laminate can be further improved.

The number of sheets (B) contained in the laminate is not particularly limited, but is preferably 1 or more, more preferably 8 or more, and preferably 26 or less, more preferably 14 or less. When the number of sheets (B) contained in the laminate is within the above range, the mechanical properties of the composite laminate can be further improved.

In the present invention, the thickness of the entire laminate is not particularly limited, but is preferably 0.5 mm or more, more preferably 1 mm or more, and preferably 3 mm or less, more preferably 2.5 mm or less. When the thickness of the entire laminate is within the above range, the mechanical properties of the composite laminate can be further improved.

In the present invention, the ratio of the average fiber length of reinforcing fiber (a1) to the average fiber diameter of reinforcing fiber (b1) (average fiber length of (a1)/average fiber diameter of (b1)) is preferably 1.1 or more, more preferably 1.5 or more, and preferably 5 or less, more preferably 3.5 or less. When the ratio (average fiber length of (a1)/average fiber diameter of (b1)) is within the above range, the mechanical properties of the composite laminate can be further improved without reducing the reinforcing effect of reinforcing fiber (b1).

In the present invention, the content of reinforcing fiber (b1) in the entire laminate is preferably 10% by mass or more and 80% by mass or less, more preferably 15% by mass or more and 70% by mass or less, and even more preferably 25% by mass or more and 55% by mass or less. By making the content of reinforcing fiber (b1) 10% by mass or more, a composite laminate having even better mechanical properties can be obtained, and by making it 80% by mass or less, the formability of the composite laminate is further improved.

In the present invention, the mass ratio ((a1)/(b1)) of reinforcing fiber (a1) to reinforcing fiber (b1) in the entire laminate is preferably 0.01 to 1, more preferably 0.01 to 0.5, and even more preferably 0.02 to 0.3. By setting the mass ratio within the above range, the mechanical properties of the composite laminate can be further improved without reducing the reinforcing strength of reinforcing fiber (b1).

The components of the composite laminate of the present invention are described below.

<Film (A)>
The film (A) used in the production of the composite laminate of the present invention is a film containing reinforcing fibers (a1) having an average fiber length of 1 μm or more and less than 100 μm, which are at least one of potassium titanate fibers and wollastonite fibers, and a thermoplastic resin (a2), and may contain spherical particles (a3) and other additives as necessary.

(Reinforcing fiber (a1))
The reinforcing fiber (a1) is a powder composed of fibrous particles, and has an average fiber length of 1 μm or more and less than 100 μm, preferably 3 μm or more and 70 μm or less, more preferably 5 μm or more and 50 μm or less. The average fiber diameter is preferably 0.01 μm or more and 15 μm or less, more preferably 0.05 μm or more and 10 μm or less, and even more preferably 0.1 μm or more and 7 μm or less.

The average aspect ratio of the reinforcing fiber (a1) is preferably 3 or more and 200 or less, more preferably 3 or more and 100 or less, and even more preferably 5 or more and 50 or less.

In this specification, a fibrous particle refers to a particle in which the longest side of the rectangular parallelepiped with the smallest volume among the rectangular parallelepipeds circumscribing the particle (circumscribing rectangular parallelepiped) is defined as the major axis L, the next longest side as the minor axis B, and the shortest side as the thickness T (B>T), with L/B and L/T both being 3 or more, and the major axis L corresponding to the fiber length and the minor axis B corresponding to the fiber diameter. A non-fibrous particle refers to a particle with an L/B smaller than 3, and non-fibrous particles with an L/B smaller than 3 and an L/T of 3 or more are called plate-like particles.

The above-mentioned average fiber length and average fiber diameter can be measured by observation with a scanning electron microscope (SEM), and the average aspect ratio (average fiber length/average fiber diameter) can be calculated from the average fiber length and average fiber diameter. For example, a plurality of reinforcing fibers (a1) are photographed with a scanning electron microscope, and 300 reinforcing fibers (a1) are arbitrarily selected from the observation image, and their fiber lengths and fiber diameters are measured. The average fiber length is calculated by accumulating all the fiber lengths and dividing by the number of fibers, and the average fiber diameter is calculated by accumulating all the fiber diameters and dividing by the number of fibers.

The reinforcing fiber (a1) is not particularly limited as long as it has an average fiber length of 1 μm or more and less than 100 μm and is at least one of potassium titanate fiber and wollastonite fiber. From the viewpoint of the sliding properties of the composite laminate, it is preferable that the Mohs hardness is 5 or less. Note that the Mohs hardness is an index that indicates the hardness of a substance, and a substance that is scratched by rubbing two minerals against each other has a lower hardness. In addition to at least one of potassium titanate fiber and wollastonite fiber, inorganic fiber, organic fiber, metal fiber, or a combination of two or more of these can be used. For example, aluminum borate, magnesium borate, xonotlite, zinc oxide, basic magnesium sulfate, etc. can be used in combination.

As potassium titanate, a wide variety of conventionally known materials can be used, including potassium tetratitanate, potassium hexatitanate, and potassium octatitanate. The dimensions of the potassium titanate are not particularly limited as long as they are within the range of the dimensions of the reinforcing fiber (a1) described above, but the average fiber length is preferably 1 μm or more and 50 μm or less, more preferably 3 μm or more and 30 μm or less, and even more preferably 10 μm or more and 20 μm or less. The average fiber diameter is preferably 0.01 μm or more and 1 μm or less, more preferably 0.05 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.7 μm or less. The average aspect ratio is preferably 10 or more, more preferably 10 or more and 100 or less, and even more preferably 15 or more and 35 or less.

Wollastonite is an inorganic fiber made of calcium metasilicate. There are no particular restrictions on the dimensions of wollastonite as long as they are within the range of the dimensions of the reinforcing fiber (a1) described above, but the average fiber length is preferably 1 μm or more and less than 100 μm, more preferably 10 μm or more and 70 μm or less, and even more preferably 20 μm or more and 40 μm or less. The average fiber diameter is preferably 0.1 μm or more and 15 μm or less, more preferably 1 μm or more and 10 μm or less, and even more preferably 2 μm or more and 7 μm or less. The average aspect ratio is preferably 3 or more, more preferably 3 or more and 30 or less, and even more preferably 5 or more and 15 or less.

In order to increase the wettability of the reinforcing fiber (a1) with the thermoplastic resin (a2) and further improve the mechanical and other physical properties of the resulting resin composition, a treatment layer made of a surface treatment agent may be formed on the surface of the reinforcing fiber (a1) used in the present invention.

Examples of surface treatment agents include silane coupling agents and titanium coupling agents. Among these, silane coupling agents are preferred, and amino-based silane coupling agents, epoxy-based silane coupling agents, and alkyl-based silane coupling agents are more preferred. The above surface treatment agents may be used alone or in combination of two or more.

Examples of amino-based silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane.

Examples of epoxy-based silane coupling agents include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

Examples of alkyl silane coupling agents include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

A known surface treatment method can be used to form a treatment layer made of a surface treatment agent on the surface of the reinforcing fiber (a1). For example, the surface treatment agent is dissolved in a solvent that promotes hydrolysis (e.g., water, alcohol, or a mixture thereof) to form a solution, and the solution is sprayed onto the reinforcing fiber (a1).

The amount of the surface treatment agent used when treating the surface of the reinforcing fiber (a1) used in the present invention is not particularly limited, but for example, a solution of the surface treatment agent may be sprayed so that the amount of the surface treatment agent is 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the reinforcing fiber (a1). By keeping the amount of the surface treatment agent within the above range, it is possible to further improve the adhesion with the thermoplastic resin (a2) and further improve the dispersibility of the reinforcing fiber (a1).

The content of reinforcing fiber (a1) is preferably 0.5% by mass or more and 35% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less, based on 100% by mass of the total amount of the components contained in film (A).

By making the content of reinforcing fiber (a1) 0.5% by mass or more, the mechanical properties of the composite laminate can be further improved, and by making it 35% by mass or less, the film formability of the film can be further improved.

(Thermoplastic resin (a2))
The thermoplastic resin (a2) is not particularly limited as long as it is a thermoplastic resin that can be formed into a film. Examples of the thermoplastic resin include polypropylene (PP) resin, polyethylene (PE) resin, cyclic polyolefin (COP) resin, and cyclic olefin copolymer (COC) resin. polyolefin resins such as polystyrene (PS) resin, syndiotactic polystyrene (SPS) resin, high impact polystyrene (HIPS) resin, acrylonitrile-butylene-styrene copolymer (ABS) resin, methyl methacrylate/styrene copolymer (MMA/styrene copolymer) resin, etc. Polymer (MS), methyl methacrylate/styrene/butadiene copolymer (MBS), styrene/butadiene copolymer (SBR ), styrene/isoprene copolymer (SIR), styrene/isoprene/butadiene copolymer (SIBR), styrene/butadiene/styrene copolymer (SBS), styrene/isoprene/styrene copolymer (SIS), styrene/ Polystyrene-based resins such as ethylene/butylene/styrene copolymer (SEBS) and styrene/ethylene/propylene/styrene copolymer (SEPS); polylactic acid (PLA) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT ) resin, polycyclohexene dimethylene terephthalate (PCT) resin, and other polyester-based resins; polyacetal (POM) resin Polycarbonate (PC) resin; polyamide 6 resin, polyamide 66 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, polyamide 6C resin, polyamide 9C resin, copolymer of polyamide 6 resin and polyamide 66 resin (polyamide 6/ aliphatic polyamide (PA) resins such as polyamide 6 resin and copolymer of polyamide 6 resin and polyamide 12 resin (polyamide 6/12 resin); polyamide MXD6 resin, polyamide MXD10 resin, polyamide 6T resin, polyamide 9T resin, polyamide 10T Semi-aromatic polyamide (PA) resins, which are composed of structural units having aromatic rings and structural units not having aromatic rings, such as polyphenylene sulfide resins; PPS resin; Polyethersulfone (PES) resin; Liquid crystal polyester (LCP) resin; Polyetherketone (PEK) resin, Polyetheretherketone (PEEK) resin, Polyetherketoneketone (PEKK) resin, Poly Polyether aromatic ketone resins such as ether ether ketone ketone (PEEKK); polyetherimide (PEI) resins; polyamideimide (PAI) resins; thermoplastic polyimide (TPI) resins; polyvinylidene fluoride (PVDF), polyvinyl fluoride ( Examples of the thermoplastic resin include fluororesins such as PVF, ethylene/tetrafluoroethylene copolymer (ETFE), etc. A mixture of two or more compatible thermoplastic resins selected from the above thermoplastic resins, i.e. Polymer alloys and the like can also be used.

Among these, the thermoplastic resin (a2) is preferably at least one selected from the group consisting of polyolefin resin, polystyrene resin, polyester resin, aliphatic polyamide (PA) resin, semi-aromatic polyamide (PA) resin, polyphenylene sulfide (PPS) resin, polyethersulfone (PES) resin, polyether aromatic ketone resin, polyetherimide (PEI) resin, and thermoplastic polyimide (TPI) resin.

From the viewpoint of further increasing the adhesion with the sheet (B), the thermoplastic resin (a2) is preferably the same type of resin as the thermoplastic resin (b2) described below. For example, when the thermoplastic resin (b2) is an aliphatic polyamide (PA) resin, the thermoplastic resin (a2) is preferably an aliphatic polyamide (PA) resin or a semi-aromatic polyamide (PA) resin.

The shape of the thermoplastic resin (a2) is not particularly limited as long as it can be melt-kneaded, and for example, any of powder, granules, and pellets can be used.

The content of thermoplastic resin (a2) is preferably 45% by mass or more and 99% by mass or less, more preferably 55% by mass or more and 98% by mass or less, and even more preferably 65% by mass or more and 92% by mass or less, based on 100% by mass of the total amount of the components contained in film (A).

(spherical particles (a3))
The film (A) may contain spherical particles (a3) within the range that does not impair the preferable physical properties of the film (A). Examples of the spherical particles (a3) include silica, glass beads, glass balloons, alumina, calcium carbonate, and magnesium carbonate. and the like, and preferably at least one selected from the group consisting of silica, alumina and glass beads.

In this specification, "spherical" includes not only perfect spheres, but also nearly spherical shapes such as ellipses, and shapes with irregularities on the surface. The aspect ratio (ratio of major axis to minor axis) of spherical silica is preferably 2 or less, and more preferably 1.5 or less. The aspect ratio can be determined, for example, by observing the shapes of 50 random particles using a scanning electron microscope (SEM) and averaging the aspect ratios of these particles.

Silica does not refer only to silicon dioxide in the narrow sense, but to silicic acid-based fillers, and can be appropriately selected from those used as conventional resin fillers, but amorphous silica is preferable.

Examples of amorphous silica include dry silica (anhydrous silica) and wet silica (hydrated silicic acid). Dry silica can be obtained, for example, by a combustion method in which silicon tetrachloride is burned in an oxygen-hydrogen flame. Wet silica can be obtained, for example, by a precipitation method or gel method in which sodium silicate is neutralized with an inorganic acid, or a sol-gel method in which alkoxysilane is hydrolyzed.

The volume average particle diameter of the spherical particles (a3) is preferably 0.01 μm or more and 100 μm or less, more preferably 0.01 μm or more and 10 μm or less, even more preferably 0.05 μm or more and 6 μm or less, particularly preferably 0.1 μm or more and 4 μm or less, and most preferably 0.3 μm or more and 2 μm or less. By setting the volume average particle diameter within the above range, the mechanical properties of the composite laminate can be further improved.

The volume average particle size is the particle size at the point corresponding to 50% volume when the cumulative frequency distribution curve of particle size is calculated assuming the total volume of the particles to be 100%, and can be measured using a particle size distribution measuring device using the laser diffraction scattering method.

The specific surface area (BET method) of the spherical particles (a3) is preferably 1 m ² /g to 30 m ² /g, more preferably 2 m ² /g to 20 m ² /g, and even more preferably 3 m ² /g to 10 m ² /g.

The specific surface area (BET method) can be measured in accordance with JIS Z8830. The BET method is a method in which nitrogen gas with a known occupancy area is adsorbed onto the surface of a sample powder particle, and the specific surface area of the sample powder particle is calculated from the amount of adsorption. The specific surface area calculated by this method is called the "BET specific surface area."

The spherical particles (a3) used in the present invention may have a treatment layer made of a surface treatment agent formed on the surface thereof in order to increase the wettability with the thermoplastic resin (a2) and further improve the mechanical and other physical properties of the resulting resin composition.

Examples of surface treatment agents include silane coupling agents and titanium coupling agents. Among these, silane coupling agents are preferred, and amino-based silane coupling agents, epoxy-based silane coupling agents, and alkyl-based silane coupling agents are more preferred. The above surface treatment agents may be used alone or in combination of two or more.

Examples of amino-based silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane.

Examples of epoxy-based silane coupling agents include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

Examples of alkyl silane coupling agents include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

A known surface treatment method can be used to form a treatment layer made of a surface treatment agent on the surface of the spherical particles (a3), for example, by dissolving the surface treatment agent in a solvent that promotes hydrolysis (e.g., water, alcohol, or a mixture thereof) to prepare a solution, and then spraying the solution onto the spherical particles (a3).

The amount of the surface treatment agent used when treating the surface of the spherical particles (a3) used in the present invention is not particularly limited, but for example, a solution of the surface treatment agent may be sprayed so that the amount of the surface treatment agent is 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the spherical particles (a3). By keeping the amount of the surface treatment agent within the above range, the adhesion with the thermoplastic resin (a2) can be further improved, and the dispersibility of the spherical particles (a3) can be further improved.

When the film (A) contains spherical particles (a3), there are no particular limitations on the content thereof as long as it is within a range that does not impair the preferred physical properties of the present invention. The content is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less, based on the total amount (100% by mass) of the components contained in the film (A).

By making the content of spherical particles (a3) 0.5% by mass or more, the mechanical properties of the composite laminate can be further improved, and by making it 20% by mass or less, the film formability of the film can be further improved.

(Other additives)
The film (A) may contain other additives within a range that does not impair its preferable physical properties. Examples of the other additives include fillers other than the above-mentioned reinforcing fibers (a1) and the above-mentioned spherical particles (a3), such as aramid fibers, polyphenylenebenzoxazole (PBO) fibers, glass fibers, carbon fibers, alumina fibers, boron fibers, silicon carbide fibers, calcium carbonate, mica, sericite, illite, talc, kaolinite, montmorillonite, boehmite, smectite, vermiculite, titanium dioxide, potassium titanate, lithium potassium titanate, and boehmite; polytetrafluoroethylene; polyolefin resins such as ethylene (PTFE), low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ultra-high molecular weight polyethylene; solid lubricants such as graphite, molybdenum disulfide, tungsten disulfide, and boron nitride; heat stabilizers such as copper compounds; light stabilizers such as hindered phenol-based light stabilizers; nucleating agents; antistatic agents such as anionic antistatic agents, cationic antistatic agents, and nonionic antistatic agents; ageing inhibitors (antioxidants); weather resistance agents; light resistance agents; and metal inactivators. agents; ultraviolet absorbers such as benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and salicylate-based ultraviolet absorbers; antibacterial and antifungal agents; deodorants; conductivity imparting agents such as carbon-based conductive agents, metal-based conductive agents, metal oxide-based conductive agents, and surfactants; dispersants; softening agents (plasticizers) such as polyester-based plasticizers, glycerin-based plasticizers, polycarboxylic acid ester-based plasticizers, phosphate ester-based plasticizers, polyalkylene glycol-based plasticizers, and epoxy-based plasticizers; carbon black, oxides Examples of the flame retardants include pigments such as titanium dioxide, colorants such as dyes, and the like; flame retardants such as phosphazene compounds, phosphate esters, condensed phosphate esters, inorganic phosphorus-based flame retardants, halogen-based flame retardants, silicone-based flame retardants, metal oxide-based flame retardants, metal hydroxide-based flame retardants, organic metal salt-based flame retardants, nitrogen-based flame retardants, and boron compound-based flame retardants; dripping inhibitors; vibration damping agents; neutralizing agents; anti-blocking agents; flow improvers; release agents such as fatty acids and fatty acid metal salts; lubricants; and impact resistance improvers, and one or more of these may be contained.

When film (A) contains other additives, the amount of the additives is not particularly limited as long as it does not impair the preferred physical properties of the present invention, and is preferably 5% by mass or less, more preferably 1% by mass or less, based on 100% by mass of the total amount of the components contained in film (A).

(Method for producing film (A))
The method for producing the film (A) is not particularly limited, and for example, known melt film-forming methods such as a T-die casting method, a calendar method, and a press method can be used.

More specifically, examples of the method include a method of directly mixing the reinforcing fiber (a1), the thermoplastic resin (a2), and, if necessary, the spherical particles (a3), and other additives so that the above content is achieved, and melt-forming the film; a method of melt-kneading the reinforcing fiber (a1), the thermoplastic resin (a2), and, if necessary, the spherical particles (a3), and other additives so that the above content is achieved, in advance to prepare pellets of the mixture, and then melt-forming the film using the pellets.

The ratio of the melt viscosity of the mixture constituting the pellets to the melt viscosity of the thermoplastic resin (a2) before mixing (mixture/thermoplastic resin (a2)) is preferably 1.01 or more, and preferably 5 or less. When the melt viscosity ratio (mixture/thermoplastic resin (a2)) is within the above range, the mechanical properties of the composite laminate can be further improved. The measurement temperature of the melt viscosity may be set to a temperature suitable for melt kneading, which is higher than the melting point when the thermoplastic resin (a2) constituting the pellets has a melting point, or higher than the glass transition temperature when the thermoplastic resin (a2) constituting the pellets does not have a melting point but has a glass transition temperature. For example, the melt viscosity of aliphatic polyamide (PA) resins and semi-aromatic polyamide (PA) resins may be measured at a temperature 25°C higher than the melting point, and the melt viscosity of polyetherimide (PEI) resins may be measured at a temperature 150°C higher than the glass transition temperature.

Either stretched or unstretched film can be used for film (A), but stretched film is preferred because it prevents wrinkles and sagging due to shrinkage during heating and melting, and further improves the appearance of the molded product. The stretching ratio is preferably 2 to 15 times. In this specification, the stretching ratio is defined as the areal ratio obtained by multiplying the stretching ratio in the transverse direction by the stretching ratio in the longitudinal direction, based on the dimensions of the film emerging from the casting roll during film production.

The thickness of each film (A) is preferably less than 500 μm, more preferably 30 μm to 450 μm, even more preferably 50 μm to 300 μm, and most preferably 100 μm to 200 μm. If it is less than 500 μm, the mechanical properties of the composite laminate can be further improved.

<Sheet (B)>
The sheet (B) used in the production of the composite laminate of the present invention is a sheet containing reinforcing fibers (b1) having an average fiber length of 1 mm or more and a thermoplastic resin (b2).

The weight per unit area of the sheet (B) is preferably 100 g/m ² or more and 1500 g/m ² or less, in consideration of smooth molding of the composite laminate of the present invention.

(Reinforcing fiber (b1))
The reinforcing fiber (b1) is not particularly limited as long as the average fiber length is 1 mm or more, and may be inorganic fiber, organic fiber, metal fiber, or a combination of two or more of these. Examples of inorganic fibers include carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, glass fiber, etc. Examples of organic fibers include aramid fiber, polyparaphenylenebenzoxazole (PBO) fiber, high-density polyethylene fiber, other general polyamide fibers, polyester, etc. Examples of metal fibers include stainless steel, iron, etc., or may be carbon fibers coated with metal. Among these, at least one selected from the group consisting of carbon fiber, glass fiber, and aramid fiber is preferable. From the viewpoint of further improving the mechanical properties such as the strength of the final molded product, carbon fiber is more preferable. Carbon fiber is a fiber produced by carbonizing acrylic fiber and pitch (a by-product of petroleum, coal, coal tar, etc.) at high temperatures, and is defined in the JIS standard as a fiber obtained by heating and carbonizing an organic fiber precursor, which is composed of 90% or more by mass of carbon. Carbon fiber using acrylic fiber is called PAN-based carbon fiber, and carbon fiber using pitch is called pitch-based carbon fiber.

If the fiber length of the reinforcing fiber (b1) is too long, the fluidity during molding may decrease, and if the fiber length is too short, it may be difficult to manufacture the reinforcing fiber paper. From the viewpoint of further improving moldability, it is preferable that the reinforcing fiber (b1) is a discontinuous fiber, and the average fiber length is preferably 1 mm or more and 100 mm or less, more preferably 10 mm or more and 90 mm or less, and even more preferably 40 mm or more and 80 mm or less. The average fiber diameter of the reinforcing fiber (b1) is preferably 1 μm or more and 50 μm or less, more preferably 3 μm or more and 20 μm or less, and even more preferably 5 μm or more and 15 μm or less. If the reinforcing fiber (b1) has the above average fiber diameter, it may be a bundle of reinforcing fibers aggregated with a binder or the like.

The content of reinforcing fiber (b1) is preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 60% by mass or less, based on 100% by mass of the total amount of the components contained in sheet (B).

By making the content of reinforcing fiber (b1) 10% by mass or more, a stronger reinforcing effect can be obtained by the fibers, and by making it 80% by mass or less, the manufacturability of the sheet can be further improved.

(Thermoplastic resin (b2))
The thermoplastic resin (b2) is not particularly limited as long as it is a thermoplastic resin that can be made into a fiber or a film, and examples thereof include polyolefin resins such as polypropylene (PP) resin, polyethylene (PE) resin, cyclic polyolefin (COP) resin, and cyclic olefin copolymer (COC) resin; polystyrene (PS) resin, syndiotactic polystyrene (SPS) resin, high impact polystyrene (HIPS) resin, acrylonitrile-butylene-styrene copolymer (ABS) resin, methyl methacrylate/styrene copolymer (MS), methyl methacrylate/styrene/butadiene copolymer (MBS), and styrene/butadiene copolymer (S polystyrene-based resins such as styrene/isoprene copolymer (SIR), styrene/isoprene/butadiene copolymer (SIBR), styrene/butadiene/styrene copolymer (SBS), styrene/isoprene/styrene copolymer (SIS), styrene/ethylene/butylene/styrene copolymer (SEBS), and styrene/ethylene/propylene/styrene copolymer (SEPS); polyester-based resins such as polylactic acid (PLA) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polycyclohexylene dimethylene terephthalate (PCT) resin; polyacetal (POM) resin polycarbonate (PC) resins; aliphatic polyamide (PA) resins such as polyamide 6 resin, polyamide 66 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, polyamide 6C resin, polyamide 9C resin, copolymer of polyamide 6 resin and polyamide 66 resin (polyamide 6/66 resin), copolymer of polyamide 6 resin and polyamide 12 resin (polyamide 6/12 resin); semi-aromatic polyamide (PA) resins consisting of structural units having aromatic rings and structural units not having aromatic rings, such as polyamide MXD6 resin, polyamide MXD10 resin, polyamide 6T resin, polyamide 9T resin, polyamide 10T resin; Examples of the thermoplastic resin include phenylene sulfide (PPS) resin, polyethersulfone (PES) resin, liquid crystal polyester (LCP) resin, polyether aromatic ketone resins such as polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, and polyether ether ketone ketone (PEEKK), polyether imide (PEI) resin, polyamide imide (PAI) resin, thermoplastic polyimide (TPI) resin, and fluorine-based resins such as polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and ethylene/tetrafluoroethylene copolymer (ETFE). A mixture of two or more compatible thermoplastic resins selected from the above thermoplastic resins, i.e., a polymer alloy, can also be used.

Among these, the thermoplastic resin (b2) is preferably at least one selected from the group consisting of polyolefin resin, polystyrene resin, polyester resin, aliphatic polyamide (PA) resin, semi-aromatic polyamide (PA) resin, polyphenylene sulfide (PPS) resin, polyethersulfone (PES) resin, polyether aromatic ketone resin, polyetherimide (PEI) resin, and thermoplastic polyimide (TPI) resin.

The shape of the thermoplastic resin (b2) is not particularly limited as long as it can be melt-kneaded; for example, powder, granules, or pellets can be used.

The content of thermoplastic resin (b2) is preferably 20% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less, and even more preferably 40% by mass or more and 70% by mass or less, based on 100% by mass of the total amount of the components contained in sheet (B).

(Method for producing sheet (B))
The sheet (B) is obtained by laminating a plurality of prepregs in which the reinforcing fibers (b1) are impregnated with the thermoplastic resin (b2) so as to have the above content, and integrating the obtained laminate by heating and pressing with a molding machine. In addition, the prepreg in which the reinforcing fibers (b1) are impregnated with the thermoplastic resin (b2) can be used as it is. That is, the prepreg in which the reinforcing fibers (b1) are impregnated with the thermoplastic resin (b2) can be used as it is as the sheet (B).

A method for manufacturing a prepreg includes preparing two sheets of thermoplastic resin (b2) in the form of a sheet such as a film, nonwoven fabric, mat, or woven or knitted fabric, sandwiching a sheet in which reinforcing fibers (b1) are arranged in a sheet form, or a sheet (nonwoven material) prepared by cutting reinforcing fibers (b1) and making a papermaking method between the two sheets, and then heating and pressing the prepreg. More specifically, two sheets of thermoplastic resin are fed from two rolls, and a sheet of reinforcing fibers supplied from a roll of a sheet of reinforcing fibers is sandwiched between the two sheets of thermoplastic resin, and then heating and pressing are performed. As a means for heating and pressing, a known method can be used, and a multi-stage process such as using two or more heat rolls or using multiple pairs of a preheating device and a heat roll may be required. Here, the thermoplastic resin constituting the sheet does not need to be of one type, and a sheet of another type of thermoplastic resin may be further laminated using the above-mentioned device.

Another method for producing a prepreg includes blending the reinforcing fiber (b1) obtained by opening a fiber bundle of the reinforcing fiber (b1) with the fibrous thermoplastic resin (b2) at a desired mass ratio, forming a sheet, laminating the sheets to obtain a nonwoven fabric, and then heating and pressing the nonwoven fabric. A commercially available blender machine can be used for blending. A carding method can be used for sheeting and lamination, and a commercially available carding machine can be used. In addition, a known means for heating and pressing can be used. The average fiber length of the fibrous thermoplastic resin (b2) used to produce the nonwoven fabric can be the same as that of the reinforcing fiber (b1) to be blended, and the fineness is preferably 2.2 dtex or more and 22 dtex or less. By setting the fineness to 2.2 dtex or more and 22 dtex or less, the dispersibility of the reinforcing fiber (b1) and the fibrous thermoplastic resin (b2) is improved, making it easier to form a more uniform nonwoven fabric. In order to further suppress the phenomenon of sheet expansion in the thickness direction when a molded article is obtained using the prepreg, it is preferable that the number of traces of a needle punch machine commonly used in cotton blending is 5 or less per cm ^2. Furthermore, it is preferable that the number of reinforcing fibers (b1) in the cross section of the prepreg that are displaced by 1 mm or more in the thickness direction is 80 or less per cm ² .

The heating temperature depends on the type of thermoplastic resin (b2), but is usually preferably 100°C or higher and 400°C or lower. On the other hand, the pressure during pressurization is usually preferably 0.1 MPa or higher and 10 MPa or lower. This range is preferable because it allows the thermoplastic resin (b2) to be further impregnated between the reinforcing fibers (b1) contained in the prepreg.

In a prepreg containing reinforcing fiber (b1) and thermoplastic resin (b2), when the reinforcing fiber (b1) is a continuous fiber oriented in one direction, the prepreg that can be used in the composite laminate of the present invention is preferably obtained by making cuts using a laser marker, cutting plotter, punching die, etc. The reinforcing fiber (b1) is cut by the cuts, and from the viewpoint of mechanical properties and fluidity, the length of the cut reinforcing fiber (b1) is preferably 5 mm or more and 100 mm or less, and more preferably 10 mm or more and 50 mm or less.

Two or more prepregs obtained as described above may be laminated so that the direction of the reinforcing fibers (b1) is quasi-isotropic or alternately laminated to produce a laminated substrate. The laminated substrate is preferably formed by laminating 4 to 96 layers of prepregs. A more preferred range for the number of prepreg layers is 8 to 32 layers. By making the number of prepreg layers 8 or more, the reinforcing fibers can be laminated in a quasi-isotropic manner, and by making the number of prepreg layers 32 or less, the workload of the lamination process can be further reduced, which is preferable.

The laminated substrate obtained as described above may be heated and pressurized to form an integrated laminated substrate, thereby producing sheet (B). At this time, the composite laminate of the present invention can be produced simultaneously with the production of sheet (B) by disposing film (A) between sheets (B) or between the laminated substrate of sheet (B) and sheet (B). It is preferable to carry out a cooling step after the heating step. By cooling, the thermoplastic resin solidifies, making it easier to handle sheet (B).

The above heating is preferably performed at 100°C or more and 400°C or less, and more preferably at 150°C or more and 350°C or less, depending on the type of thermoplastic resin (b2) contained in the prepreg. Preheating may also be performed prior to the above heating. Preheating is generally performed at 150°C or more and 400°C or less, and preferably at 200°C or more and 380°C or less.

The pressure applied to the laminated substrate during the above pressurization is preferably 0.1 MPa or more and 10 MPa or less, and more preferably 0.2 MPa or more and 2 MPa or less. This pressure is determined by dividing the pressing force by the area of the laminated substrate.

The heating and pressurizing time is preferably 0.1 to 30 minutes, more preferably 0.5 to 20 minutes. The cooling time after heating and pressurizing is preferably 0.5 to 30 minutes.

The thickness of the sheet (B) integrated through the above molding can be selected as desired depending on the shape of the target part, and from the standpoint of moldability and mechanical properties, it is preferably 0.3 mm or more and 15 mm or less, and more preferably 1 mm or more and 12 mm or less.

<Method of manufacturing composite laminate>
The composite laminate of the present invention can be produced by integrating the film (A) and the sheet (B) by applying heat and pressure to a laminate in which the film (A) is directly laminated between a plurality of sheets (B). The film (A) may also be laminated on one or both sides of the sheet (B). It is preferable to carry out a cooling step after the heating step. By cooling, the thermoplastic resin is solidified, making it easier to handle the composite laminate.

When heating the laminate, it is preferable to heat at 100°C or more and 400°C or less, and more preferable to heat at 150°C or more and 350°C or less, depending on the type of thermoplastic resin (a2) contained in the film (A) and the type of thermoplastic resin (b2) contained in the sheet (B). In addition, preheating may be performed prior to the above heating. Preheating is usually performed at 150°C or more and 400°C or less, preferably 200°C or more and 380°C or less.

The pressure applied to the laminate in the above pressurization is preferably 0.1 MPa or more and 10 MPa or less, and more preferably 0.2 MPa or more and 2 MPa or less. This pressure is the value obtained by dividing the pressing force by the area of the laminate.

The heating and pressurizing time is preferably 0.1 to 30 minutes, more preferably 0.5 to 20 minutes. The cooling time after heating and pressurizing is preferably 0.5 to 30 minutes.

When the thermoplastic resin contained in the laminate has a melting point (Tm), the mold temperature (Th) of the molding machine during the heating is preferably Tm≦Th≦(Tm+100) (°C), and more preferably (Tm+10)≦Th≦(Tm+80) (°C). When the thermoplastic resin contained in the laminate does not have a melting point (Tm) but has a glass transition temperature (Tg), the mold temperature (Th) of the molding machine during the heating is preferably Tg≦Th≦(Tg+100) (°C), and more preferably (Tg+10)≦Th≦(Tg+80) (°C). By setting the mold temperature (Th) of the molding machine within the above range, the laminate can be integrated while preventing expansion of the mold and suppressing deterioration of the resin.

The difference (Th-Tc) between the mold temperature (Th) of the molding machine during the heating and the mold temperature (Tc) of the molding machine when cooling the laminate is preferably 10≦(Th-Tc)≦250(°C), and more preferably 30≦(Th-Tc)≦200(°C). By keeping the mold temperature difference within the above range, more uniform melting and solidification of the thermoplastic resin is possible, and the durability of the resulting composite laminate can be further improved.

The overall thickness of the composite laminate of the present invention can be selected as desired depending on the shape of the target component, and can be, for example, 1 mm or more and 10 mm or less from the standpoint of moldability and mechanical properties.

The composite laminate of the present invention can be used as an intermediate material for molding that can be formed into any shape by press molding such as stamping, and can be formed into various parts and components for automobiles, electrical and electronic devices (computer housings, tablets, etc.), etc.

The present invention will be described in detail below based on examples and comparative examples, but the present invention is not limited to these in any way. The raw materials used in the examples and comparative examples are specifically as follows.

(Reinforcing fiber (a1))
Potassium titanate fiber (product name: TISMO D101, manufactured by Otsuka Chemical Co., Ltd., average fiber length: 15 μm, average fiber diameter: 0.5 μm, average aspect ratio: 30)

(spherical particles (a3))
Spherical silica (product name: SC2500-SEJ, manufactured by Admatechs Co., Ltd., amorphous silica, spherical particles, volume average particle size: 0.6 μm, specific surface area: 6.0 m ² /g, surface treatment agent: 3-glycidyl xypropyltrimethoxysilane)

(Thermoplastic resin (a2))
Polyamide MXD10 resin (product name: LEXTER8500, manufactured by Mitsubishi Gas Chemical Co., Ltd.)

(others)
Plate-like talc (product name: TALC GH7, manufactured by Hayashi Kasei Co., Ltd., average major axis: 5.8 μm, thickness: 0.1 μm)

<Test Examples 1 to 6>
The mixture was melt-kneaded in a twin-screw extruder to produce pellets in the proportions shown in Table 1. The cylinder temperature of the twin-screw extruder was 240°C.

After drying the resulting pellets, a film extruder (Toyo Seiki Co., Ltd., Labo Plastomill 4C150-01 connected to a single-screw extruder D2020 (L/D = 20)) was used to extrude the molten resin from a T-die (width: 150 mm, thickness: 0.2 mm) at a cylinder temperature of 240°C. The molten resin was uniaxially stretched through a film take-up device to the desired thickness, yielding a film. The film thickness was 100 μm.

<Example 1, Comparative Examples 1 and 2>
The films produced in Test Examples 1 and 2 were used as films (A), and a sheet formed from a nonwoven fabric of carbon fibers (average fiber length: 70 mm, average fiber diameter: 7 μm) and polyamide 6 resin fibers (sheet thickness: 3 mm, carbon fiber content: 40 mass%, polyamide 6 resin content: 60 mass%) was used as sheet (B).

The above film (A) and sheet (B) were laminated in the lamination order shown in Table 2, sandwiched between two imide films (product name: UPILEX 75S, manufactured by Ube Industries, Ltd.), and pressed in a press machine (manufactured by Toyo Seiki Co., Ltd., product name: Mini Test Press MP-WCH) under conditions of a top plate temperature of 280°C, a preheating time of 5 minutes, a pressure of 4.8 MPa, and a pressurizing time of 3 minutes, and after pressing, the imide film was peeled off to produce a composite laminate. The thickness of the obtained composite laminate was measured and is shown in Table 2.

<Examples 2 to 3, Comparative Examples 3 to 4>
The films produced in Test Examples 3 to 6 were designated as films (A), and a sheet formed from a nonwoven fabric of carbon fibers (average fiber length: 70 mm, average fiber diameter: 7 μm) and polyamide 6 resin fibers (sheet thickness: 3 mm, carbon fiber content: 40 mass%, polyamide 6 resin content: 60 mass%) was designated as sheet (B).

The above film (A) and sheet (B) were laminated in the lamination order shown in Table 3, sandwiched between two imide films (product name: UPILEX 75S, manufactured by Ube Industries, Ltd.), and pressed in a press machine (manufactured by Toyo Seiki Co., Ltd., product name: Mini Test Press MP-WCH) under conditions of a top plate temperature of 280°C, a preheating time of 5 minutes, a pressure of 4.8 MPa, and a pressurizing time of 3 minutes, and after pressing, the imide film was peeled off to produce a composite laminate. The thickness of the obtained composite laminate was measured and is shown in Table 3.

<Measurement of bending strength>
The composite laminates of Examples 1 to 3 and Comparative Examples 1 to 4 manufactured above were cut into the shape of JIS test pieces (bending test pieces) using an abrasive water jet device. The cutting conditions were nozzle diameter φ0.76 mm, water pressure 400 MPa, speed 200 mm/min, water amount about 2.5 L/min, and abrasive usage amount: garnet #80 400 g/min. The bending test pieces were cut so that the length direction coincided with the drawing direction of the film in Test Examples 1 to 6.

The obtained bending test piece was subjected to a three-point bending test with a support distance of 60 mm using an Autograph AG-5000 (manufactured by Shimadzu Corporation) in accordance with JIS K7171 to measure the bending strength. The results are shown in Tables 2 and 3. In the stacking sequence, A represents film (A), B represents sheet (B), and / represents stacking. The numbers in parentheses represent the number of stacked sheets. In the stacking sequence, the left side represents the front side, and the right side represents the back side. Specifically, Example 1 has the stacking structure shown in Figure 1. Comparative Example 1 and Comparative Example 2 have the same stacking structure as Figure 1, except that the two films (A) at the center in Figure 1 are not provided and the total number of sheets (B) is 12 layers. Examples 2 to 3 and Comparative Examples 3 to 4 have the same stacking structure as Figure 1, except that the five-layer sheet (B) on the back side in Figure 1 is changed to four layers.

As shown in Table 2, Example 1 has a higher bending strength than Comparative Example 1 and Comparative Example 2, despite having a lower content of reinforcing fiber (b1), which is thought to contribute significantly to improving bending strength. This shows that the presence of film (A) in the intermediate layer has the unexpected effect of significantly improving bending strength.

As shown in Table 3, Comparative Example 3 and Comparative Example 4 show that the bending strength decreases when plate-like talc is added to film (A). However, Example 2 and Comparative Example 4 show that the bending strength improves when potassium titanate fiber is added. This shows that the bending strength improves when the reinforcing material is in the form of fibers.

In addition, from Examples 2 and 3, it can be seen that when spherical silica is further contained in the film (A), the bending strength is further improved, and therefore it can be seen that there is a synergistic effect when spherical particles are used in combination with inorganic fibers.

1, 21, 31...Laminate 2...Central portion 2a...First main surface 2b...Second main surface 3, 4...Outermost layer

Claims (12)

In a composite laminate containing reinforcing fibers and a thermoplastic resin,
The composite laminate is formed by integrating a laminate including a film (A) and a sheet (B) by thermocompression bonding,
The laminate has a portion where the film (A) is laminated between a plurality of the sheets (B) so as to be in direct contact with the sheet (B),
The film (A) contains reinforcing fibers (a1) having an average fiber length of 1 μm or more and less than 100 μm, which are at least one of potassium titanate fibers and wollastonite fibers, and a thermoplastic resin (a2),
The sheet (B) contains reinforcing fibers (b1) having an average fiber length of 1 mm or more and a thermoplastic resin (b2),
A composite laminate, characterized in that the ratio of the average fiber length of the reinforcing fibers (a1) to the average fiber diameter of the reinforcing fibers (b1) (average fiber length of (a1) / average fiber diameter of (b1)) is more than 1 and 10 or less. The composite laminate according to claim 1, characterized in that the mass ratio ((a1)/(b1)) of the reinforcing fiber (a1) to the reinforcing fiber (b1) in the entire laminate is 0.01 or more and 1 or less. The composite laminate according to claim 1 or 2, characterized in that the thermoplastic resin (a2) is at least one selected from the group consisting of polyolefin resins, polystyrene-based resins, polyester-based resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyethersulfone resins, polyether aromatic ketone resins, polyetherimide resins, and thermoplastic polyimide resins. The composite laminate according to any one of claims 1 to 3, characterized in that the content of the reinforcing fiber (a1) is 0.5% by mass or more and 35% by mass or less in 100% by mass of the total amount of the components contained in the film (A). The composite laminate according to any one of claims 1 to 4, characterized in that the film (A) further contains spherical particles (a3). The composite laminate according to any one of claims 1 to 5, characterized in that the reinforcing fiber (b1) is at least one type selected from the group consisting of carbon fiber, glass fiber, and aramid fiber. The composite laminate according to any one of claims 1 to 6, characterized in that the content of the reinforcing fiber (b1) is 10% by mass or more and 80% by mass or less in 100% by mass of the total amount of the components contained in the sheet (B). The composite laminate according to any one of claims 1 to 7, characterized in that the thermoplastic resin (b2) is at least one selected from the group consisting of polyolefin resins, polystyrene-based resins, polyester-based resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyethersulfone resins, polyether aromatic ketone resins, polyetherimide resins, and thermoplastic polyimide resins. The composite laminate according to any one of claims 1 to 8, wherein the film (A) is further provided on at least one of the outermost layers on both sides of the laminate. The composite laminate according to any one of claims 1 to 9, wherein the laminate has a portion in which the sheet (B) is laminated between a plurality of the films (A) so as to be in direct contact with the film (A). The composite laminate according to any one of claims 1 to 10, which is used as an automobile component or an electric/electronic device component. A method for producing a composite laminate containing reinforcing fibers and a thermoplastic resin,
A step (I) of preparing a laminate by stacking a film (A) containing reinforcing fibers (a1) having an average fiber length of 1 μm or more and less than 100 μm, the reinforcing fibers being at least one of potassium titanate fibers and wollastonite fibers, and a thermoplastic resin (a2), and a sheet (B) containing reinforcing fibers (b1) having an average fiber length of 1 mm or more, and a thermoplastic resin (b2);
and (II) a step of integrating the laminate by thermocompression to obtain a composite laminate.
a laminate having a laminated structure in which the film (A) has a portion between a plurality of the sheets (B) and laminated so as to be in direct contact with the sheet (B), and the laminate is prepared so that a ratio of an average fiber length of the reinforcing fibers (a1) to an average fiber diameter of the reinforcing fibers (b1) (average fiber length of (a1)/average fiber diameter of (b1)) is more than 1 and 10 or less.

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