JP2024088819A - Method of manufacturing molded body - Google Patents

Abstract

To provide a method of manufacturing a molded body capable of suppressing disorder of a continuous fiber and ensuring mechanical properties even when a three-dimensional shaped mold including a curved surface is used in which a fiber orientation of the continuous fiber is particularly likely to become disordered.SOLUTION: In a method of manufacturing a molded body, a composite material A containing a discontinuous fiber and a resin M1 and a composite material B containing a continuous fiber and a resin M2 are laminated and compression-molded. An arrangement surface X of the composite material B to a mold has a three-dimensional shape including a curved surface, and curves toward a bundle width direction of the continuous fiber. A relation between a maximum thickness Tmax and a minimum thickness Tmin of the continuous fiber contained in the molded body is 1≤Tmax/Tmin≤1.5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a molded body by stacking composite material A and composite material B and compression molding them.

In recent years, molded articles reinforced with discontinuous or continuous fibers have been attracting attention as structural components for automobiles and other vehicles due to their excellent mechanical properties.

Patent Document 1 describes a method for producing a molded product using a continuous reinforced fiber prepreg made of uncured thermosetting matrix resin and a thermoplastic resin sheet, with the mold temperature set to match the viscosity range specific to the thermoplastic resin sheet.

Patent document 2 describes a molded body that is formed by providing a barrier layer between a sheet molding compound layer and a continuous fiber reinforcement layer, the barrier layer having a structure in which the fibers cross each other.

JP 2008-230236 A International Publication No. 2018/101245

However, the continuous fiber reinforced prepreg described in Patent Document 1 has a low degree of cure of 10% or less for the thermosetting resin contained in the prepreg, so when it is compression molded together with other materials (such as discontinuous fiber reinforced composite materials), the continuous fibers contained in the prepreg follow the flow direction of the other materials. As a result, the continuous fibers become disordered, and the molded product cannot maintain high physical properties.

In addition, the composite material described in Patent Document 2 has a barrier layer between the sheet molding compound layer and the continuous fiber reinforcement layer, which means that an unnecessary layer is required when manufacturing a molded body, and the labor required for lamination increases. Furthermore, problems arise in ensuring interlaminar shear strength between the three layers, and differences in the shrinkage rates between the layers can cause the molded body to warp.

The object of the present invention is to provide a method for producing a molded body that can suppress the disorder of continuous fibers and ensure mechanical properties, even when using a molding mold with a three-dimensional shape that includes curved surfaces, in which the fiber orientation of the continuous fibers is particularly likely to become disordered.

In order to solve the above problems, the present invention provides the following means.
1. A method for producing a molded product by laminating and compression molding a composite material A containing discontinuous fibers and a resin M1 and a composite material B containing continuous fibers and a resin M2, comprising the steps of:
The surface X of the composite material B placed on the molding die has a three-dimensional shape including a curved surface and is curved toward the bundle width direction of the continuous fibers,
The relationship between the maximum thickness Tmax and the minimum thickness Tmin of the continuous fibers contained in the molded body is 1≦Tmax/Tmin≦1.5.
2. The method for producing a molded article according to 1. above, wherein the arrangement surface X is curved in an arc or folded state toward the bundle width direction of the continuous fibers.
3. The method for producing a molded body according to 1. or 2. above, wherein the interlaminar shear strength between composite material A and composite material B in the molded body is 30 MPa or more.
4. The method for producing a molded body according to any one of 1. to 3. above, wherein the resin M2 is a semi-cured thermosetting resin and has a complex viscosity η2 of 8000 Pa·s or more and 30000 Pa·s or less.
5. The method for producing a molded article according to any one of 1. to 4., wherein the resin M2 is a semi-cured thermosetting resin having a degree of cure of 50% or more.
6. The method for producing a molded article according to 4. or 5. above, wherein the resin M2 is completely cured during molding to produce the molded article.
7. The method for producing a molded product according to any one of 4. to 6. above, wherein the composite material B contains a latent curing agent, and the latent curing agent utilizes at least one selected from the group consisting of ion reaction, heat dissolution, molecular sieve, microcapsules, and UV curing.
8. The method for producing a molded article according to any one of 1. to 3. above, wherein the resin M1 and the resin M2 are thermoplastic resins.
9. The method for producing a molded article according to 8. above, wherein the complex viscosities of the resins M1 and M2 satisfy the following relationship:
3×η1<η2<30000 (Pa·s) and η1<500 (Pa·s)
however,
η1 (Pa·s): Complex viscosity of resin M1 at a shear rate of 2 (1/s) η2 (Pa·s): Complex viscosity of resin M2 at a shear rate of 2 (1/s).
10. The method for producing a molded article according to any one of 1. to 9. above, which satisfies the following formula:
(Maximum width of fiber bundle Wmax-minimum width of fiber bundle Wmin)/average width of fiber bundle Wave<0.25
11. The method for producing a molded product according to any one of 1. to 10. above, wherein the continuous fibers contained in composite material B are uniaxially oriented continuous fibers and oriented in the longitudinal direction of composite material B.
12. The method for producing a molded product according to any one of 1. to 10. above, wherein the continuous fibers contained in composite material B are biaxially oriented continuous fibers and are oriented in the longitudinal direction of composite material B and in a direction perpendicular to the longitudinal direction.

When a composite material reinforced with discontinuous fibers and a composite material reinforced with continuous fibers are laminated and molded, the continuous fibers are not disturbed during molding, making it possible to produce a molded product with stable and high mechanical properties.

1 is a schematic diagram illustrating a method for producing a molded article of the present invention. 1A and 1B are schematic diagrams showing the relationship between the composite material B of the present invention and a lower molding die. 1A and 1B are schematic diagrams showing the relationship between the composite material B of the present invention and a lower molding die.

[Reinforced fiber]
Although there is no particular limitation on the fibers contained in the composite material A or the composite material B, it is preferable that the fibers are reinforcing fibers. Specifically, it is preferable that the fibers are one or more reinforcing fibers selected from the group consisting of carbon fibers, glass fibers, aramid fibers, boron fibers, and basalt fibers.

[Carbon fiber]
The fibers contained in the composite material A or B of the present invention are preferably carbon fibers. Generally, polyacrylonitrile (PAN)-based carbon fibers, petroleum/coal pitch-based carbon fibers, rayon-based carbon fibers, cellulose-based carbon fibers, lignin-based carbon fibers, phenol-based carbon fibers, and the like are known as carbon fibers, and any of these carbon fibers can be suitably used in the present invention. Among them, it is preferable to use polyacrylonitrile (PAN)-based carbon fibers in the present invention because of their excellent tensile strength.

[Fiber diameter of carbon fiber]
When the fibers contained in the composite material A or composite material B of the present invention are carbon fibers, the fiber diameter of the single yarn of the carbon fiber used (generally, the single yarn may be called a filament) may be appropriately determined according to the type of carbon fiber, and is not particularly limited. The average fiber diameter is usually preferably in the range of 3 μm to 50 μm, more preferably in the range of 4 μm to 12 μm, and even more preferably in the range of 5 μm to 8 μm. When the carbon fiber is in the form of a fiber bundle, it refers to the diameter of the carbon fiber (single yarn) constituting the fiber bundle, not the diameter of the fiber bundle. The average fiber diameter of the carbon fiber can be measured, for example, by the method described in JIS R-7607:2000.

[Glass fiber]
The fibers contained in the composite material A or the composite material B of the present invention may be glass fibers. There is no particular limitation on the type of glass fiber, and any glass fiber made of E glass, A glass, or C glass may be used, or these may be used in combination. There is no particular limitation on the glass fiber in the present invention, but the average fiber diameter of the glass fiber is preferably 1 μm to 50 μm, more preferably 5 μm to 20 μm.

[Sizing agent]
The carbon fiber or glass fiber used in the present invention may have a sizing agent attached to the surface. When using reinforcing fibers with a sizing agent attached thereto, the type of the sizing agent can be appropriately selected according to the types of reinforcing fibers and matrix resin, and is not particularly limited.

[Composite Material A]
[Discontinuous fibers contained in composite material A]
1. Weight average fiber length The weight average fiber length of the discontinuous fibers contained in the composite material A is preferably 0.3 mm or more, more preferably 0.3 mm or more and 100 mm or less, even more preferably 0.3 mm or more and 80 mm or less, even more preferably 0.3 mm or more and 50 mm or less, and even more preferably 0.3 mm or more and 40 mm or less. When the weight average fiber length of the reinforcing fibers is 100 mm or less, the fluidity of the composite material A is improved, and the desired molded body shape is easily obtained during compression molding. On the other hand, when the weight average fiber length is 0.3 mm or more, the mechanical strength of the molded body is easily improved.

Discontinuous fibers may be used in combination with reinforcing fibers having different fiber lengths. In other words, the reinforcing fibers may have a single peak in the weight average fiber length, or may have multiple peaks.

If the average fiber length of the reinforcing fibers is 3 mm or more, for example, the fiber lengths of 100 fibers randomly extracted from the molded body can be measured to the nearest 1 mm using a caliper or the like, and the average fiber length can be calculated based on the following formula (a). The average fiber length is measured as the weight average fiber length (Lw).

When the fiber length of each reinforcing fiber is Li and the number of fibers measured is j, the number average fiber length (Ln) and the weight average fiber length (Lw) can be calculated by the following formulas (a) and (b).
Ln=ΣLi/j Formula (a)
Lw=(ΣLi ² )/(ΣLi)...Equation (b)
When the fiber length is constant, the number average fiber length and the weight average fiber length have the same value.
The reinforcing fibers can be extracted from the molded body, for example, by subjecting the molded body to a heat treatment at 500° C. for about 1 hour and removing the resin in a furnace.

[Fiber volume fraction VfA of composite material A]
In the present invention, the fiber volume fraction VfA contained in the composite material A is defined by the following formula (c).
Fiber volume ratio (VfA)=100×fiber volume/(fiber volume+resin volume of composite material A) (Equation (c))
More specifically, the fiber volume fraction (VfA) is preferably 10 Vol% or more and 50 Vol% or less, more preferably 15 Vol% or more and 45 Vol% or less, and even more preferably 20 Vol% or more and 40 Vol% or less.

When the reinforcing fiber volume fraction (VfA) is 10 Vol% or more, the desired mechanical properties are easily obtained. On the other hand, when the reinforcing fiber volume fraction (VfA) does not exceed 50 Vol%, the flowability is good when used in press molding, etc., and the desired molded shape is easily obtained.

[Fiber morphology of discontinuous fibers contained in composite material A]
1. Bundle form The reinforcing fibers are discontinuous fibers having a fiber length of 5 mm or more, and preferably contain carbon fibers a1 having a fiber bundle width of less than 0.3 mm and carbon fiber bundles a2 having a bundle width of 0.3 mm or more and 3.0 mm or less. The volume ratio of the reinforcing fiber bundles a2 to the reinforcing fibers contained in the composite material A is preferably 5 Vol% or more and less than 95 Vol%, and more preferably 10 Vol% or more and less than 90 Vol%.

2. Dispersion In the composite material A, the reinforcing fibers are preferably dispersed in an in-plane direction. The in-plane direction is a direction perpendicular to the plate thickness direction of the molded body, and means an arbitrary direction of a parallel plane perpendicular to the plate thickness direction.

Furthermore, it is preferable that the reinforcing fibers are dispersed two-dimensionally and randomly in the in-plane direction. When composite material A is compression molded without flowing, the shape of the reinforcing fibers is largely maintained before and after molding, so it is preferable that the reinforcing fibers contained in the molded product obtained by molding composite material A are also dispersed two-dimensionally and randomly in the in-plane direction of the molded product.

Here, "dispersed randomly in two dimensions" refers to a state in which the reinforcing fibers are oriented randomly in the in-plane direction of the molded body, rather than in a specific direction such as one direction, and are arranged in the sheet plane overall without showing a specific directionality. Composite material A obtained using discontinuous fibers that are randomly dispersed in this way is a substantially isotropic composite material A that does not have anisotropy in the plane.

The degree of two-dimensional random orientation is evaluated by determining the ratio of the tensile modulus in two mutually orthogonal directions. If the (Eδ) ratio, calculated by dividing the larger of the tensile modulus values measured in any direction of the molded body and the direction orthogonal thereto by the smaller, is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less, it can be evaluated that the reinforcing fibers are two-dimensionally randomly dispersed. Since the molded body has a shape, when the resin contained in the composite material A is a thermoplastic resin, it is preferable to heat it to a softening temperature or higher to return it to a flat plate shape and solidify it. At this time, the composite material A and the composite material B are separated,
Only composite material A is taken out. Then, a test piece is cut out and the tensile modulus is measured, thereby making it possible to confirm the random dispersion state in two dimensions.

[Resin M1 contained in composite material A]
There is no particular limitation on the resin M1 contained in the composite material A, and it may be a thermosetting resin or a thermoplastic resin.

1. Thermoplastic resin The preferred resin M1 contained in the composite material A is a thermoplastic resin. The type of thermoplastic resin is not particularly limited, and one having a desired softening point or melting point can be appropriately selected and used. As the thermoplastic matrix resin, one having a softening point in the range of 180°C to 350°C is usually used, but is not limited thereto.

Examples of types of thermoplastic resins include vinyl chloride resins, vinylidene chloride resins, vinyl acetate resins, polyvinyl alcohol resins, polystyrene resins, acrylonitrile-styrene resins (AS resins), acrylonitrile-butadiene-styrene resins (ABS resins), acrylic resins, methacrylic resins, polyethylene resins, polypropylene resins, various thermoplastic polyamide resins, polyacetal resins, polycarbonate resins, polyethylene terephthalate resins, polyethylene naphthalate resins, polybutylene naphthalate resins, polybutylene terephthalate resins, polyarylate resins, polyphenylene ether resins, polyphenylene sulfide resins, polysulfone resins, polyether sulfone resins, polyether ether ketone resins, and polylactic acid resins.

The thermoplastic resin may be either a crystalline resin or an amorphous resin. In the case of a crystalline resin, preferred crystalline resins include polyamide resins such as nylon 6, polyethylene terephthalate resins, polybutylene terephthalate resins, polyethylene resins, polypropylene resins, polyacetal resins, and polyphenylene sulfide resins. Among these, polyamide resins, polybutylene terephthalate resins, and polyphenylene sulfide resins are preferably used because of their excellent heat resistance and mechanical strength.

Nylon (hereinafter sometimes abbreviated as "PA"), which is a type of polyamide resin, includes PA6 (also called polycaproamide, polycaprolactam, or poly-ε-caprolactam), PA26 (polyethylene adipamide), PA46 (polytetramethylene adipamide), PA66 (polyhexamethylene adipamide), PA69 (polyhexamethylene azepamide), PA410 (polytetramethylene sebacamide), PA610 (polyhexamethylene sebacamide), PA611 (polyhexamethylene undecamide), PA612 (polyhexamethylene dodecamide), PA11 (polyundecane amide), PA12 (polydodecanamide), PA1212 (polydodecamethylene dodecamide), PA6T (polyhexamethylene At least one selected from the group consisting of polyhexamethylene isophthalamide, ...

2. Thermosetting resin The resin M1 contained in the composite material A may be a thermosetting resin. In the case of a thermosetting resin, an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, a phenolic resin, or the like is used. As the thermosetting resin, one type may be used alone, or two or more types may be used in combination. More specifically, the composite material A may be a sheet molding compound (sometimes called SMC) containing reinforcing fibers and a thermosetting resin.

3. Other Agents The composite material A used in the present invention may contain additives such as various fibrous or non-fibrous fillers of organic or inorganic fibers, flame retardants, UV resistance agents, stabilizers, release agents, pigments, softeners, plasticizers, surfactants, etc., within the scope of not impairing the object of the present invention.

[Composite Material B]
[Continuous fibers contained in composite material B]
1. General The composite material B in the present invention includes continuous fibers. The continuous fibers are also continuous fiber bundles and have a bundle width. The width and thickness of the fiber bundle are defined as follows, when considering three mutually orthogonal straight lines (x-axis, y-axis, and z-axis): the fiber direction of the fiber bundle is the x-axis direction, and the maximum length ymax in the y-axis direction perpendicular to the x-axis direction and the maximum length zmax in the z-axis direction perpendicular to the x-axis direction are defined as the longer of the two, the width and the thickness, respectively.

The continuous fibers may be in the form of a sheet, such as a woven or knitted fabric, a sheet-like material with unidirectionally aligned strands, or a multiaxial fabric. Note that a multiaxial fabric generally refers to a fabric in which bundles of fiber reinforcement aligned in one direction are formed into a sheet and laminated at different angles (multiaxial fabric substrate), and then stitched with a stitch thread such as polyamide thread, polyester thread, or glass fiber thread that penetrates the laminate in the thickness direction and travels back and forth between the front and back surfaces of the laminate in the surface direction.

2. Uniaxial orientation The continuous fibers contained in the composite material B of the present invention are preferably uniaxially oriented continuous fibers. Uniaxially oriented continuous fibers mean that they have only one orientation direction and are not oriented in other directions. When uniaxially oriented continuous fibers are used, the problem of the fiber width expanding during molding becomes more pronounced. It is more preferable that the continuous fibers contained in the composite material B are uniaxially oriented continuous fibers and are oriented in the longitudinal direction of the composite material B.

3. Biaxial orientation The continuous fibers contained in composite material B are preferably biaxially oriented continuous fibers oriented in the longitudinal direction of composite material B and in a direction perpendicular to the longitudinal direction. In this case, composite material B may be biaxially oriented by laminating uniaxially oriented continuous fiber prepregs. This is because the continuous fibers oriented in a direction perpendicular to the longitudinal direction suppress disturbance of the continuous fibers in the longitudinal direction. In the case of biaxial orientation, the "disturbance of the orientation of the continuous fibers" in the present invention refers to "disturbance of the continuous fibers in the longitudinal direction of composite material B".

[Fiber volume fraction of composite material B (VfB)]
In the present invention, the fiber volume fraction VfB contained in the composite material B is defined by the following formula (d).
Fiber volume ratio (VfB)=100×fiber volume/(fiber volume+resin volume of composite material B) Formula (d)
More specifically, the fiber volume fraction (VfB) is preferably 10 Vol% or more and 60 Vol% or less, more preferably 30 Vol% or more and 60 Vol% or less, and even more preferably 40 Vol% or more and 60 Vol% or less.

When the reinforcing fiber volume fraction (VfB) is 10 Vol% or more, the desired mechanical properties are easily obtained. On the other hand, when the reinforcing fiber volume fraction (VfB) does not exceed 60 Vol%, a certain amount of resin is present around the reinforcing fibers, and resin M1 of composite material A and resin M2 of composite material B can be stably adhered to each other, making it easier to maintain high physical properties.

[Resin M2 contained in composite material B]
1. Thermosetting resin 1.1 Types The resin M2 contained in the composite material B may be a thermosetting resin. The thermosetting resin contained in the composite material B may be an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, a phenolic resin, or the like, but an epoxy resin is preferred from the viewpoint of adhesion and heat resistance. As the thermosetting resin, one type may be used alone, or two or more types may be used in combination.

1.2 Degree of cure The resin M2 contained in the composite material B is preferably a thermosetting resin, more preferably a semi-cured thermosetting resin. The degree of cure of the semi-cured resin is preferably 50% or more, more preferably 55% or more, even more preferably 60% or more, even more preferably 65% or more, and even more preferably 70% or more.

There are several ways to adjust the degree of hardening, including using one type of hardener and adjusting the heating temperature, or using two or more types of hardeners with different reaction temperatures and reacting only the hardener that reacts at a lower temperature.

The degree of cure of a thermosetting resin can be determined by mixing a curing agent with unreacted thermosetting resin, allowing it to react, and measuring the amount of heat of reaction (using a differential scanning calorimeter, DSC). Specifically, samples are made by adding various amounts of curing agent to unreacted thermosetting resin, and the amount of reaction heat when the thermosetting resin is cured is measured using DSC. When a certain amount of curing agent is added, the amount of reaction heat becomes constant, so the amount of curing agent added when the amount of reaction heat becomes constant is set as the reference amount (the amount of curing agent that can give a degree of cure of 100%). The degree of cure is determined by the ratio of the amount of curing agent added to the reference amount. For example, if the amount of curing agent added to the reference amount is 50%, the degree of cure is 50%.

By using a semi-cured thermosetting resin, it becomes easier to maintain the straightness of the orientation of the continuous fibers contained in composite material B during molding, and even if the arrangement surface X has a three-dimensional shape, it becomes easier to manufacture a molded body in which the relationship between the maximum thickness Tmax and the minimum thickness Tmin of the continuous fibers satisfies 1≦Tmax/Tmin≦1.5.

1.3 Curing agent 1.3.1 One type of curing agent There is no particular limitation on the type of curing agent, but it is preferable to use one that allows easy adjustment of the degree of curing. When using one type of curing agent, it is preferable to use one that allows the curing reaction to proceed slowly over a wide temperature range.

1.3.2 Two types of curing agents When using two types of curing agents, it is preferable to use a combination that has a sufficient difference in the temperature range in which the curing reaction proceeds, in order to utilize them in the two-stage curing described below. When using two types of curing agents, it is preferable that the temperature ranges in which the reaction of each curing agent starts are separated by 30°C or more, and more preferably by 50°C or more.

It is preferable that the curing agent that reacts at a low temperature can be cured in the temperature range from room temperature to 100°C.

On the other hand, from the viewpoint of manufacturing efficiency, the curing agent reacted on the high temperature side is preferably a latent curing agent that reacts at a temperature above a specific temperature. The latent curing agent is preferably at least one selected from the group consisting of ionic reaction, heat dissolution, molecular sieves, microcapsules, and UV curing. A latent curing agent may be added to a composite of uncured thermosetting resin material and continuous fibers to form composite material B. If the latent curing agent is encapsulated in a molecular sieve or microcapsules, the curing agent can be eluted by a specific trigger. Examples of epoxy resin curing agents include Lewis acid complexes that utilize ionic reaction, and dicyandiamide and imidazole compounds that utilize dissolution by heating.

1.4 Two-stage curing It is preferable to carry out a first stage of curing during the production process of composite material B to produce a semi-cured resin, and then carry out a second stage of curing when composite material A and composite material B are laminated to produce a molded product (two-stage curing).

When uniaxially oriented continuous fibers are used as the composite material B, it is preferable that the composite material B is made by pultrusion molding and semi-cured. With pultrusion molding, it is possible to semi-cure while impregnating the unreacted thermosetting resin in the die, and it is easy to manufacture the desired fiber basis weight and resin ratio. At this time, there is no particular limit to the temperature for semi-curing, and it is sufficient to set the temperature according to the characteristics of the curing agent used. The preferred temperature range for semi-curing is 100°C or less. By setting the temperature at 100°C or less, the process window (processing condition range) of the second stage curing heating temperature can be kept wide. The semi-cured thermosetting resin contained in the composite material B can be completely cured when laminated with the composite material A and molded. In other words, the resin M2 can be completely cured during molding to produce a molded body. In other words, the composite material B in a semi-cured state can be shaped in the molding process. When completing the curing when molding the resin M2, it is recommended to use the latent curing agent.

1.5 Microcapsulated hardener contained in composite material B Composite material B may contain a microcapsulated hardener. The microcapsulated hardener has a mechanism in which the capsules collapse in a specific temperature range and the hardening component contained therein is eluted into the matrix.

(1) Use in the first stage of two-stage curing When resin M2 is cured in two stages, the microcapsule curing agent may be used in the first stage of curing. In this case, the microcapsules do not collapse at room temperature, and the microcapsules can be collapsed in the temperature range during the production of composite material B.

(2) Use in the second stage of two-stage curing When resin M2 is cured in two stages, the microcapsule curing agent may be used in the second stage of curing. In this case, it is preferable that the microcapsules do not collapse in the manufacturing process of composite material B, in other words, it is preferable that the microcapsules collapse in a temperature range of 120 degrees or more.

On the other hand, it is preferable to completely cure the semi-cured resin when press molding. It is preferable that the microcapsules collapse during press molding, the curing agent contained in the microcapsules dissolves, and curing proceeds within the mold to completely cure. In this case, the temperature at which complete curing occurs is the mold temperature for press molding.

(3) Use in the first and second stages of two-stage curing By using two types of microcapsule hardeners, resin M2 can be hardened by the microcapsule hardeners in both (1) the first stage curing and (2) the second stage.

1.6 Complex viscosity of resin M2 (η2 (Pa s))
Resin M2 in the present invention is preferably a semi-cured thermosetting resin having a complex viscosity η2 of 8000 Pa·s or more and 30000 Pa·s or less. By satisfying this range, when composite material A and composite material B are laminated and molded, composite material B can be easily shaped to conform to the shape of a molding die (particularly a three-dimensional shape including a curved surface), and the straightness of the continuous fibers contained in composite material B during molding can be ensured, so that a manufacturing method that can achieve both shaping ability and high mechanical properties can be provided.

More preferably, resin M2 is a semi-cured thermosetting resin, and the complex viscosity η2 is more preferably 8000 Pa·s or more and 20000 Pa·s or less, and even more preferably 10000 Pa·s or more and 16000 Pa·s or less.

2. Thermoplastic Resin The resin M2 may be a thermoplastic resin. More specifically, it is more preferable that the resins M1 and M2 are thermoplastic resins, and the complex viscosities of the resins M1 and M2 satisfy the following relationship:
3×η1<η2<30000 (Pa·s) and η1<500 (Pa·s)
however,
η1 (Pa·s): Complex viscosity of resin M1 at a shear rate of 2 (1/s) η2 (Pa·s): Complex viscosity of resin M2 at a shear rate of 2 (1/s).

Composite material A is preferably a material that flows easily to prevent chipping (sometimes called short shots) at the ends of the molded body, while composite material B is preferably less flowable than composite material A to provide partial reinforcement.

By satisfying 3 x η1 < η2 < 30,000 (Pa·s) and η1 < 500 (Pa·s), a large difference in fluidity during molding can be achieved between composite material A and composite material B, ensuring that resin M1 has greater fluidity than resin M2. If 3 x η1 < η2, resin M2 of composite material B will flow less easily than composite material A, making it easier to reinforce the molded body with continuous fibers.

When resin M1 is nylon 6 (melting point: approximately 225°C, sometimes called PA6), the complex viscosity is 500 Pa·s at 245°C, and it is preferable to mold it while heating to a temperature higher than this.

When resin M2 is PA66 (polyhexamethylene adipamide, melting point: approximately 260°C), the complex viscosity is 1550 Pa·s at 263°C. As the viscosity changes significantly near the melting point, molding must be done under strict temperature control. In addition to PA66, resin M2 can also be made from MXD6-PA (melting point: approximately 240°C), PA410 (polytetramethylene sebacamide, melting point: approximately 240°C), etc.

3. UV-curable resin In order to reduce the influence of temperature rise, a UV-curable resin may be used as the resin M2 contained in the composite material B.

[Compression molding]
The molded article of the present invention is produced by laminating composite material A and composite material B and compression molding the laminate.
Compression molding is often called press molding, but there are two main types of press molding: cold press molding and hot press molding.

1. Cold press molding Cold press molding is a method applied when the resin M1 is a thermoplastic resin. In this case, the resin M2 may be a thermoplastic resin or a thermosetting resin.

Resin M1 is preheated to a temperature above which it can be shaped (step A1), and the mold is controlled to a constant temperature at which resin M1 solidifies and molded. Composite material A is at its highest temperature in the preheated state, and in (step A2) its temperature drops steadily. In other words, composite material A continues to cool without being heated within the mold. Cold press molding includes at least the following steps (step A1) to (step A3).

(Step A1)
This is a step of heating the composite material A to a first predetermined temperature. For example, it is preferable to heat the composite material A to a moldable temperature or higher (above the softening point) of the resin M1.
When the resin M2 contained in the composite material B is a thermoplastic resin, the composite material B may or may not be heated. When the composite material B is heated, it is preferable to heat it to a moldable temperature or higher. When the composite material B is not heated, the composite material B may be heated by receiving heat from the composite material A when the composite materials A and B are laminated.
When the resin M2 contained in the composite material B is a thermosetting resin, it may or may not be heated.

(Step A2)
A step of placing and pressing composite material A and composite material B in a mold adjusted to a second predetermined temperature.
The molding pressure at this time is not particularly limited, but is preferably less than 20 MPa relative to the mold cavity projected area, and more preferably 10 MPa or less. By setting the pressure to less than 20 MPa, it is not necessary to have a large-scale molding facility even in the production of a large molded body. If the pressure is less than 20 MPa relative to the mold cavity projected area, it is easier to maintain the straightness of the continuous fibers of the composite material B during molding.

(Step A3)
This is a process in which pressure is maintained to fully solidify composite material A and composite material B. If resin M2 is a semi-cured thermosetting resin, it will harden when exposed to heat from the molding die and composite material A, and can be made to go from a semi-cured state to a fully cured state.

A molded body is manufactured by carrying out steps (Step A1) to (Step A3).

(Other processes)
The above steps (Step A1) to (Step A3) must be performed in the order mentioned above, but other steps may be included between each step.
(i) The other step is, for example, a shaping step performed before (step A2) in which a shaping mold different from the mold used in (step A2) is used to pre-shape the product into the shape of the cavity of the mold.
(ii) In step A2, vacuum press molding may be used, in which compression molding is performed under vacuum.

2. Hot Press Molding Hot press molding is a molding method in which the resin M1 is heated in a molding die.
For example, (Step B1) to (Step B4) will be described for the case where the resin M1 and the resin M2 are thermosetting resins.
(Step B1) A step of stacking composite material A and composite material B and placing them in a molding die.
(Step B2) A step of heating and pressurizing the composite material A and the composite material B placed on the molding die.
Composite material A and composite material B placed on the mold are heated to a temperature above the temperature at which curing begins. Resin M1 and resin M2 are clamped in the mold, pressurized, and shaped. The curing proceeds as they are heated, and the shaping is completed at the same time. If resin M2 is a semi-cured thermosetting resin, curing proceeds in step B2, and the resin can be changed from a semi-cured state to a fully cured state.
(Step B3) A step of maintaining the pressure at a target pressure. The target pressure is 0.1 MPa to 20 MPa, and preferably 0.2 MPa to 10 MPa. The estimated time for maintaining the pressure is 1 to 20 minutes. (Step B4) A step of cooling.

Molding can be completed by carrying out steps (Step B1) and (Step B2).
The above steps must be performed in the order listed above, but may include other steps.

[Placement surface X]
1. Shape The method for producing a molded article of the present invention is a method for producing a molded article by laminating a composite material A containing discontinuous fibers and a resin M1 and a composite material B containing continuous fibers and a resin M2, and compression molding the laminate, comprising the steps of:
The surface X of the composite material B placed on the mold has a three-dimensional shape including a curved surface and is curved toward the bundle width direction of the continuous fibers. After the composite materials A and B are laminated, the composite material B may be present on the surface of the laminate, or may be sandwiched between the composite materials A and present in the center of the laminate.

1.1 Three-dimensional shape The placement surface X is the surface on which composite material B is placed in the mold, and is not necessarily the contact surface with the mold. In other words, after composite material A and composite material B are laminated, if composite material B exists on the surface of the laminate, the placement surface of composite material B in the mold becomes the contact surface with the mold. On the other hand, if composite material B exists in the center of the laminate sandwiched between composite materials A, composite material B is placed in the mold via composite material A, so composite material B does not come into contact with the mold. After being placed in the mold, composite material B is molded, so the shape of the placement surface of the mold becomes the shape of the molded product as it is. The placement surface is shown, for example, at 103 in FIG. 1.

The three-dimensional shape may include bent or curved surfaces. The three-dimensional shape may also include planar regions.

An example of a curved surface is the surface shown by 301 in Figure 3. The angle of curvature is preferably 3° or more, more preferably 5° or more, and even more preferably 7° or more. With an inclination of 3° or more, 5% or more of the compressive force is applied in the bundle width direction of the continuous fibers contained in composite material B, making the problem of the present invention more pronounced. The angle of curvature is shown by θ1 in Figure 3.

In the case of a curved surface, for example, a hemispherical surface or a spherical surface can be mentioned. More specifically, for example, a part of a curved surface constituting the surface of a sphere or an ellipsoid can be mentioned, specifically shown as 201 in FIG. 2. There is no particular limit to the radius or length of the curvature, but if the angle between the tangent of the arrangement surface X and the horizontal plane is 3 degrees or more, the problem of the fiber bundle being disturbed becomes significant. This is because a part of the compression force is applied in the bundle direction of the continuous fibers contained in the composite material B. The angle between the tangent of the arrangement surface X and the horizontal plane is preferably 3 degrees or more, more preferably 5 degrees or more, and even more preferably 7 degrees or more.

1.2 The arrangement surface X is curved toward the bundle width direction of the continuous fibers The arrangement surface X is a three-dimensional shape including a curved surface, and is curved toward the bundle width direction of the continuous fibers contained in the composite material B. In other words, the arrangement surface X is a three-dimensional shape including a curved surface, and the curved surface is curved toward the bundle width direction of the continuous fibers (103 in FIG. 1). The composite material B is heated in advance or heated in a molding die, and is deformed into a three-dimensional shape that is a shape curved toward the bundle width direction of the continuous fibers. It is preferable that the composite material B before heating has a flat plate shape and becomes a three-dimensional shape after molding. The bundle width direction of the continuous fibers is, for example, the X-axis direction in FIG. 1, FIG. 2, and FIG. 3.

It is preferable that the arrangement surface X bends in an arc or bent state toward the bundle width direction of the continuous fibers. In FIG. 2, an arc is depicted in the bundle width direction of the continuous fibers, and in FIG. 3, a bent state is depicted toward the bundle width direction of the continuous fibers.

When the continuous fibers described in Patent Document 1 (JP 2008-230236 A) are used, for example, the orientation of the continuous fibers is easily disturbed at the arrangement surface X. This is because the degree of cure of the thermosetting resin prepreg containing the continuous fibers described in Patent Document 1 (JP 2008-230236 A) is low at 10% or less, and the viscosity during molding is too low. For example, if a thermosetting resin prepreg containing the continuous fibers described in Patent Document 1 (JP 2008-230236 A) is arranged at the location shown in 201 in Figure 2 or 301 in Figure 3, the continuous fibers will be subjected to a compressive force in the bundle width direction during compression molding, and will also be dragged by the molding flow of the composite material A containing discontinuous fibers, causing the orientation of the continuous fibers to become disturbed.

The conventional problems become more pronounced when the arrangement surface X is curved in an arc or folded state toward the bundle width direction of the continuous fibers. When it has such a shape, the compression force of molding is applied in the bundle width direction of the continuous fibers contained in the composite material B, making it easier for the continuous fibers to become disordered. With the manufacturing method of the present invention, the continuous fibers are not disordered, and a molded product with stable high mechanical properties can be manufactured.

1.3 Placement surface X and lamination surface A specific example of composite material A and composite material B for producing a molded product is shown in Figure 1. Figure 1 shows a case where flat-plate-shaped composite material A and composite material B are placed and laminated in a mold with a large curvature.

When composite material A and composite material B are placed in a mold, the lamination surface of composite material A and composite material B may coincide with placement surface X. In other words, composite material B may be completely laminated with composite material A, rather than being partially laminated.

By molding composite material A and composite material B separately and joining the two, it is possible to produce a molded body with continuous fibers arranged in a three-dimensional shape, but this lengthens the manufacturing process and increases manufacturing costs. According to the present invention, composite material A and composite material B can be molded as a single unit, reducing manufacturing costs.

[Maximum and minimum thicknesses of continuous fibers contained in molded product]
The relationship between the maximum thickness Tmax and the minimum thickness Tmin of the continuous fibers contained in the molded product of the present invention is 1≦Tmax/Tmin≦1.5. Here, the continuous fibers contained in the molded product refer to the same fibers as the continuous fibers contained in composite material B, which are in a molded state.

That is, the present invention provides
A method for producing a molded body by laminating and compression molding a composite material A containing discontinuous fibers and a resin M1 and a composite material B containing continuous fibers and a resin M2, comprising the steps of:
The surface X of the composite material B placed on the molding die has a three-dimensional shape including a curved surface and is curved toward the bundle width direction of the continuous fibers,
The relationship between the maximum thickness Tmax and the minimum thickness Tmin of the continuous fibers contained in the molded body is 1≦Tmax/Tmin≦1.5.
It can also be said that.

Preferably, 1≦Tmax/Tmin<1.3, more preferably, 1≦Tmax/Tmin<1.2, and even more preferably, 1≦Tmax/Tmin<1.1.

If Tmax/Tmin≦1.5, this means that the continuous fibers are aligned in the direction of orientation without any disturbance, and a molded product with high mechanical properties can be obtained.

The continuous fibers contained in the molded body are the continuous fibers contained in composite material B before molding, and the maximum thickness Tmax and minimum thickness Tmin of the continuous fibers are measured by observing the molded body after molding. Measurements are not made of the continuous fibers contained in composite material B before molding.

The maximum thickness Tmax and minimum thickness Tmin of the continuous fibers are measured as described below, but it is preferable to measure at a location within 100 mm in the fiber direction.

[Interlaminar shear strength between composite material A and composite material B]
The interlaminar shear strength between composite material A and composite material B in the molded body is preferably 30 MPa or more. "In the molded body" means the interlaminar shear strength between composite material A and composite material B after molding. To distinguish the parts that were composite material A and composite material B before molding, it is sufficient to observe the fibers contained in the molded body. The parts containing discontinuous fibers are the parts that were composite material A, and the parts containing continuous fibers are the parts that were composite material B. If the interlaminar shear strength is 30 MPa or more, the reinforcing effect of composite material B can be highly expressed. When resin M1 and resin M2 are both thermoplastic resins, the interlaminar shear strength can be increased by increasing the compatibility of resin M1 and resin M2.

When resin M2 is a thermosetting resin, by using a semi-cured thermosetting resin as resin M2, resin M2 can crosslink with resin M1 during molding, increasing the interlaminar shear strength. In other words, if resin M2 is a semi-cured thermosetting resin, it is possible to prevent the continuous fibers from being disturbed by compression molding and to increase the interlaminar shear strength with composite material A.

The interlaminar shear strength between composite material A and composite material B in the molded body can be measured at the part where they are laminated in a flat plane.

[Fluctuation rate of fiber bundle width]
The disorder of the continuous fibers of the composite material B can be evaluated by measuring the bundle width of the continuous fiber bundle and using the following formula.
(Maximum width of fiber bundle Wmax - Minimum width of fiber bundle Wmin) / Average width of fiber bundle Wave
In the present invention, the fluctuation rate of the fiber bundle width is preferably less than 0.25. By making the fluctuation rate of the fiber bundle width less than 0.25, the fiber width is stabilized, which means that the disorder of the continuous fibers contained in the molded product can be suppressed. In this case, high mechanical properties can be maintained.
(Maximum width Wmax of fiber bundle - Minimum width Wmin of fiber bundle)/Average width Wave of fiber bundle is preferably less than 0.20, more preferably less than 0.15, and even more preferably less than 0.10.

The present invention will be described in detail below using examples, but the present invention is not limited to these.

1. Materials 1.1 Carbon fiber Teijin carbon fiber "Tenax" (registered trademark) STS40-24K (average fiber diameter 7 μm, number of single fibers 24,000)
1.2 Thermoplastic resin Polyamide 6 (A1030 manufactured by Unitika Ltd., sometimes abbreviated as PA6).
1.3 Thermosetting resin composition Epoxy resin (epoxy resin E206S manufactured by Konishi Co., Ltd.)
Hardener: Mitsubishi Chemical Corporation hardener ST15 (first stage hardener)
Shikoku Chemical Industry Co., Ltd. hardener 2E4MZ-CN (second stage hardener)

2. Various Measurements The values in the present examples were determined according to the following methods.
(1) Measurement of fiber volume fraction (VfA, VfB) contained in composite material A sample of 100 mm × 100 mm was cut out from composite material A (or composite material B), and the sample was heated in an electric furnace (FP410 manufactured by Yamato Scientific Co., Ltd.) heated to 550°C under a nitrogen atmosphere for 1 hour to burn off organic substances such as the matrix resin.
The weights of the reinforcing fibers and the thermoplastic resin were calculated by weighing the samples before and after the burn-off. The volume fraction of the reinforcing fibers was then calculated using the specific gravity of each component.
Fiber volume ratio (VfA)=100×fiber volume/(fiber volume+resin volume of composite material A) Formula (c)
Fiber volume ratio (VfB)=100×fiber volume/(fiber volume+resin volume of composite material B) Formula (d)

(2) Maximum thickness Tmax and minimum thickness Tmin
The cross section of the composite material B was observed so that the cross section of the continuous fibers in the fiber direction of the produced molded product could be observed. The minimum and maximum thicknesses of the continuous fibers contained in the composite material B after the molded product were measured by observing 10 cross sections evenly spaced within a range of 100 mm in the fiber direction.
Tmin: minimum thickness of the continuous fibers contained in composite material B after molding. Tmax: maximum thickness of the continuous fibers contained in composite material B after molding. From the obtained Tmin and Tmax, the shape retention of the continuous fibers was evaluated by the following formula.
Tmax/Tmin: Shape retention of continuous fibers The closer the Tmax/Tmin value is to 1, the higher the shape retention, and the larger the number, the lower the shape retention.

(3) Shear strength between composite materials A and B Interlaminar shear strength was used as an index of the interlaminar shear strength between composite materials A and B. The interlaminar shear test method was based on JIS K7078 and was calculated using the following formula (e). The interlaminar shear strength was measured at a location where composite materials A and B were laminated to form a plane.
τ = 3P / 4bh ... formula (e)
τ: Interlaminar shear strength (MPa)
P: Breaking load (N)
b: Width of test piece (mm)
h: thickness of test piece n (mm)

(4) Complex Viscosity of Resin M2 in Composite Material B The complex viscosity of Resin M2 contained in Composite Material B was measured using a rheometer (Discovery HR30, manufactured by TA Instruments).
When resin M2 is a thermosetting resin, both a decrease in viscosity due to heating and an increase in viscosity due to curing can occur. Therefore, resin M2 was heated from room temperature to 200°C at a temperature increase rate of 5°C per minute at a frequency of 2 Hz to measure the complex viscosity, and the lowest complex viscosity value during the temperature increase measurement was determined as the complex viscosity of resin M2.

(5) Coefficient of Variation of Fiber Bundle Width In order to evaluate the disorder of the continuous fibers contained in composite material B after molding, the coefficient of variation of the fiber bundle width of the continuous fibers was measured.
The continuous fibers contained in the composite material B that had formed a molded body were observed, and a target area was set to a length of 100 mm along the continuous fibers.

The maximum width, minimum width, and average width of the fiber bundle in the target area were used to calculate the width according to the following formula (f).
(Wmax-Wmin)/Wave ... formula (f)
Wmax: Maximum width of fiber bundle Wmin: Minimum width of fiber bundle Wave: Average width of fiber bundle

[Example 1]
1. Preparation of Composite Material A Teijin's carbon fiber "Tenax" (registered trademark) STS40-24K (average fiber diameter 7 μm, number of single fibers 24,000) cut to a fiber length of 20 mm was used as the carbon fiber, and Unitika's nylon 6 resin A1030 was used as the resin to prepare a composite material of carbon fiber and nylon 6 resin in which the carbon fibers were oriented two-dimensionally randomly based on the method described in U.S. Patent No. 8,946,342. The obtained composite material was heated at 2.0 MPa for 5 minutes in a press machine heated to 270°C, to obtain a plate-shaped composite material A with a width of 250 mm, length of 250 mm, and average thickness of 2.5 mm.
Analysis of the carbon fibers contained in the plate-shaped composite material A revealed that the carbon fiber volume fraction (Vf) was 35%, the fiber length of the carbon fibers was a constant length, and the weight average fiber length was 20 mm.

2. Preparation of composite material B 2.1 Preparation of thermosetting resin composition As a thermosetting resin, epoxy resin E206S manufactured by Konishi Co., Ltd. was prepared, and 14.7 phr of hardener ST15 manufactured by Mitsubishi Chemical Corporation and 5.0 phr of hardener 2E4MZ-CN manufactured by Shikoku Kasei Kogyo Co., Ltd. were mixed with this. The blending ratio of hardener ST15 was 50% of the amount required to completely cure epoxy resin E206S with hardener ST15 alone. The blending ratio of hardener 2E4MZ-CN was 50% or more of the amount required to completely cure epoxy resin E206S with hardener 2E4MZ-CN alone. Note that phr (per hundred resin) indicates the weight ratio when the weight of epoxy resin in the resin mixture is 100.

The amount of hardener required for complete curing is determined by preparing samples with various amounts of hardener added to the epoxy resin in various mixing ratios, measuring the amount of reaction heat during curing with a DSC (X-DSC7000 manufactured by SII Nano Technology), and finding that when the hardener is added at a certain mixing ratio or above, the amount of reaction heat becomes constant, and this refers to the amount of hardener to be added when the amount of reaction heat becomes constant.

2.2 Preparation of Composite Material B Carbon fiber "Tenax" (registered trademark) STS40-48K (average fiber diameter 7 μm, fineness 3200 tex, density 1.77 g/cm ³ ) manufactured by Teijin Limited was used as the carbon fiber, and it was passed through a drawing die having a cross-sectional area of 20 mm x 0.5 mm, and impregnated with a thermosetting resin in the drawing die. The obtained carbon fiber impregnated with the thermosetting resin was cut to a length of 100 mm, heated in an oven at 80°C for 20 minutes, and only the curing agent ST15 was reacted to obtain a composite material B having a width of 20 mm x length of 100 mm x thickness of 0.5 mm containing a thermosetting resin with a semi-cured resin M2. Since only the curing agent ST15 was reacted, the degree of cure of the resin M2 was 50%.

3. Mold and molding conditions The surface X of the mold on which composite material B was placed had a three-dimensional shape including a curved surface, and a hemispherical mold with a radius of 75 mm was prepared so that fiber disorder of the continuous fibers when the surface was curved toward the bundle width direction of the continuous fibers could be evaluated (Figure 1).

Composite material A heated to 270°C was placed in a mold heated to 150°C, and composite material B at room temperature (25°C) was layered on the apex of the hemisphere, after which the mold was clamped and held at a pressure of 20 MPa for 3 minutes before the molded body was taken. The results are shown in Table 1.

For measuring the interlaminar shear strength, a sample was prepared in addition to the molded product created in Figure 1. Specifically, a plate-shaped composite material A measuring 250 mm wide x 250 mm long x 2.5 mm in average thickness was laminated with composite material B measuring 20 mm wide x 100 mm long x 0.5 mm in thickness to create a planar molded product. The planar portion where composite material A and composite material B were laminated was cut out, and the interlaminar shear strength was measured.

[Examples 2 to 6]
Molded articles were produced in the same manner as in Example 1, except that the degree of curing was changed by changing the amount of curing agent added as shown in Table 1. The results are shown in Table 1.

[Example 7]
A molded article was produced in the same manner as in Example 1, except that uniaxially oriented continuous fibers (oriented in only one direction, not in any other direction) and a material containing PA66 as the matrix resin (Akulon (registered trademark) PA66-HC12 manufactured by DSM Engineering Materials Co., Ltd.) were used as composite material B. The results are shown in Table 1.

[Example 8]
Composite material B was prepared by using a material (Akulon (registered trademark) PA6-HC10UD manufactured by DSM Engineering Materials Co., Ltd.) containing uniaxially oriented continuous fibers (oriented in only one direction, not in other directions) and PA6 as the matrix resin, so that the continuous fibers were oriented in the longitudinal direction of composite material B and in a direction perpendicular to the longitudinal direction. The material (Akulon (registered trademark) PA6-HC10UD manufactured by DSM Engineering Materials Co., Ltd.) had a thickness of 0.25 mm, and two layers were laminated in the longitudinal direction and one layer was laminated in a direction perpendicular to the longitudinal direction to prepare composite material B. Except for this, a molded body was prepared in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Examples 1 and 2]
Molded articles were produced in the same manner as in Example 1, except that the degree of cure was changed as shown in Table 1. The results are shown in Table 1.

[Reference Example 1]
A molded article was produced in the same manner as in Example 1, except that uniaxially oriented continuous fibers (oriented in only one direction, not in any other direction) and a material containing PA6 as the matrix resin (Akulon (registered trademark) PA6-HC10UD manufactured by DSM Engineering Materials Co., Ltd.) were used as composite material B. The results are shown in Table 2.

[Reference Example 2]
A molded article was produced in the same manner as in Example 1, except that uniaxially oriented continuous fibers (oriented in only one direction, not in any other direction) and a material containing PA-MXD6 as a matrix resin (Reny Tape manufactured by Mitsubishi Engineering Plastics Corporation) were used as composite material B. The results are shown in Table 2.

[Reference Example 3]
A molded article was produced in the same manner as in Example 1, except that uniaxially oriented continuous fibers (oriented in only one direction, not in any other direction) and a material containing PA410 as the matrix resin (Eco-Paxx (registered trademark) PA410-HC12UD manufactured by DSM Engineering Materials Co., Ltd.) were used as the composite material B. The results are shown in Table 2.

The molded article of the present invention and the molded articles obtained by molding the same can be used in various components, such as structural members of automobiles, various electrical products, machine frames and housings, and any other location where shock absorption is desired. It is particularly suitable for use as automobile parts.

101: Molding mold (upper mold)
102: Molding mold (lower mold)
103: Placement surface X
A: Composite material A
B: Composite material B
201: curved surface 301: bent surface θ1: angle of bending

Claims (12)

A method for producing a molded body by laminating and compression molding a composite material A containing discontinuous fibers and a resin M1 and a composite material B containing continuous fibers and a resin M2, comprising the steps of:
The surface X of the composite material B placed on the molding die has a three-dimensional shape including a curved surface and is curved toward the bundle width direction of the continuous fibers,
The relationship between the maximum thickness Tmax and the minimum thickness Tmin of the continuous fibers contained in the molded body is 1≦Tmax/Tmin≦1.5. The method for manufacturing a molded body according to claim 1, wherein the arrangement surface X is curved in an arc or folded state toward the bundle width direction of the continuous fibers. The method for producing a molded body according to claim 1 or 2, wherein the interlaminar shear strength between composite material A and composite material B in the molded body is 30 MPa or more. The method for producing a molded body according to any one of claims 1 to 3, wherein resin M2 is a semi-cured thermosetting resin and the complex viscosity η2 of resin M2 is 8000 Pa·s or more and 30000 Pa·s or less. The method for manufacturing a molded body according to any one of claims 1 to 4, wherein resin M2 is a semi-cured thermosetting resin with a degree of curing of 50% or more. The method for producing a molded body according to claim 4 or 5, in which the resin M2 is completely cured during molding to produce the molded body. The method for producing a molded body according to any one of claims 4 to 6, wherein the composite material B contains a latent curing agent, and the latent curing agent utilizes at least one selected from the group consisting of ionic reaction, heat dissolution, molecular sieve, microcapsules, and UV curing. The method for producing a molded body according to any one of claims 1 to 3, wherein resin M1 and resin M2 are thermoplastic resins. The method for producing a molded product according to claim 8 , wherein the complex viscosities of the resins M1 and M2 satisfy the following relationship:
3×η1<η2<30000 (Pa·s) and η1<500 (Pa·s)
however,
η1 (Pa·s): Complex viscosity of resin M1 at a shear rate of 2 (1/s) η2 (Pa·s): Complex viscosity of resin M2 at a shear rate of 2 (1/s). The method for producing a molded article according to claim 1 , which satisfies the following formula:
(Maximum width of fiber bundle Wmax-minimum width of fiber bundle Wmin)/average width of fiber bundle Wave<0.25 The method for producing a molded body according to any one of claims 1 to 10, wherein the continuous fibers contained in composite material B are uniaxially oriented continuous fibers oriented in the longitudinal direction of composite material B. The method for producing a molded body according to any one of claims 1 to 10, wherein the continuous fibers contained in composite material B are biaxially oriented continuous fibers oriented in the longitudinal direction of composite material B and in a direction perpendicular to the longitudinal direction.