JP7523253B2 - Molded body and its manufacturing method - Google Patents

Description

The present invention relates to a molded body having a member containing continuous fiber reinforced resin and a member containing discontinuous fiber reinforced resin bonded to the surface of the member, and a method for manufacturing the same.

2. Description of the Related Art Fiber-reinforced resin materials containing reinforcing fibers and thermoplastic resins are lightweight and have excellent strength, and therefore are widely used in various industrial applications such as automobile parts, aircraft parts, and railway parts.
As the above-mentioned parts, etc., molded bodies are manufactured in which another resin material or fiber reinforced resin material is further joined to a fiber reinforced resin material. A known manufacturing method for such molded bodies is to place a fiber reinforced resin material (first resin material) in a heated molding die, fill the cavity of the molding die with molten resin material or fiber reinforced resin material (second resin material), and bond the first resin material and the second resin material by hardening the molten resin to obtain a molded body.
Furthermore, in the above-mentioned method, in order to improve the bonding strength between the above-mentioned resin materials, for example, Patent Document 1 describes a method in which a temperature difference is provided between the lower and upper dies of a molding die, the temperature of the lower die is adjusted to a temperature below the melting point of the resin of the continuous fiber reinforcement material (first resin material), and the temperature of the upper die is adjusted to a temperature equal to or higher than the melting point, and then another resin material (second resin material) is filled in.
Patent Document 2 describes a method in which a surface processing step is performed in which the surface of a fiber-reinforced resin material (a first resin material) is heated to a temperature above the melting point or glass transition point of the resin to process the surface into an uneven shape or to expose reinforcing fibers on the surface, and then another resin material (a second resin material) is injection molded onto the processed surface.

Patent No. 5712857 JP 2016-210080 A

However, in the molding methods described in Patent Documents 1 and 2, particularly when the cavity filled with the second resin material is discontinuous, if a continuous fiber reinforced resin material is used as the first resin material, the pressure applied to the continuous fiber reinforced resin material causes the continuous reinforcing fibers to bite (enter) into the cavity, causing twisting of the continuous reinforcing fibers at the joint between the first resin material and the second resin material. If such twisting occurs, sufficient strength cannot be obtained at the joint, and the molded body may break from the twist when an impact is applied to the joint.
Furthermore, when the surface of a fiber-reinforced resin material is heated after molding, the smoothness of the surface is lost, resulting in a problem of impaired appearance.

The present invention aims to provide a molded article having excellent strength and appearance, which has a member containing continuous fiber reinforced resin and a member containing discontinuous fiber reinforced resin bonded to the surface of the member, and a method for manufacturing the same.

As a result of extensive investigations to solve the above-mentioned problems, the inventors have found that in a molded body having a first member containing continuous fiber reinforced resin and a second member containing discontinuous fiber reinforced resin joined to a surface of the first member, the above-mentioned problems can be solved by setting the ratio of the thickness of the first member at the joint between the first member and the second member to the thickness of the first member at a portion other than the joint between the first member and the second member within a specific range, and have completed the present invention.
That is, the present invention is as follows.

[1]
A method for producing a molded body,
The molded body is
A first member including a continuous fiber reinforced resin including continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin including discontinuous reinforcing fibers,
At a joint between the first member and the second member, the first member bites into the second member, or the second member bites into the first member,
A ratio (t1/t) of a height t1 of the continuous reinforcing fiber at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00,
The manufacturing method includes:
A continuous fiber reinforced resin containing continuous reinforcing fibers is heated and then placed in a mold for molding, and the mold is clamped to mold a first member;
and heating, in the mold for molding, a joining side surface of the first member at a portion where the second member is to be joined or the entire joining side surface including the joining side surface, and then molding the second member using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.
When molding the second member, the height of a cavity in the mold for molding, which corresponds to the shape of the first member, is set to a range of ±25% of the thickness of the first member before molding (joining) the second member;
The molding of the second member is injection molding.
A method for producing a molded body, comprising:
[2]
A method for producing a molded body,
The molded body is
A first member including a continuous fiber reinforced resin including continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin including discontinuous reinforcing fibers,
At a joint between the first member and the second member, the first member bites into the second member, or the second member bites into the first member,
A ratio (t1/t) of a height t1 of the continuous reinforcing fiber at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00,
The manufacturing method includes:
A continuous fiber reinforced resin containing continuous reinforcing fibers is heated and then placed in a mold for a first member, and the mold is clamped to mold the first member;
The first member is removed from the first member mold, and a joining side surface of a portion of the first member to which a second member is to be joined or an entire joining side surface including the joining side surface is heated;
The heated first member is placed in a mold for molding, and a second member is molded using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers,
When molding the second member, the height of a cavity in the mold for molding, which corresponds to the shape of the first member, is set to a range of ±25% of the thickness of the first member before molding (joining) the second member;
The molding of the second member is injection molding.
A method for producing a molded body, comprising:
[3]
A method for producing a molded body,
The molded body is
A first member including a continuous fiber reinforced resin including continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin including discontinuous reinforcing fibers,
At a joint between the first member and the second member, the first member bites into the second member, or the second member bites into the first member,
A ratio (t1/t) of a height t1 of the continuous reinforcing fiber at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00,
The manufacturing method includes:
The method includes heating a continuous fiber reinforced resin containing continuous reinforcing fibers, placing the heated continuous fiber reinforced resin in a mold for molding, clamping the mold with a clamping force such that a pressure in a clamping direction applied to the continuous fiber reinforced resin is 10 MPa or less to mold a first member, and then molding a second member using the heated discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.
When molding the second member, the height of a cavity in the mold for molding, which corresponds to the shape of the first member, is set to a range of ±25% of the thickness of the first member before molding (joining) the second member;
The molding of the second member is injection molding.
A method for producing a molded body, comprising:
［ 4 ］
The method for producing a molded body according to any one of [1] to [3], wherein a ratio ((t1-t)/W) of a difference t1-t obtained by subtracting the thickness t from the thickness t1 to a width W of the second member at the joint is -0.50 to 10.00.
［ ５ ］
The method for producing a molded body according to any one of [1] to [4] , wherein the discontinuous reinforcing fibers have a fiber length of less than 3 mm.
［ ６ ］
The method for producing a molded body according to any one of [1] to [4] , wherein the discontinuous reinforcing fibers have a fiber length of 3 mm or more.
［ ７ ］
The method for producing a molded product according to any one of [1] to [6], wherein, regarding a tensile strength of the first member in a direction along a surface of the first member, a ratio (σ _{B 1'/σ B 1) of the tensile strength σ B 1 at} the _joint to the tensile strength σ B 1 at a portion other than the joint is 0.65 or more.
［ 8 ］
The method for producing a molded product according to [7], wherein a ratio (σ _J /σ _B 1 ' ) of an adhesive strength σ _J between the first member and the second member at the joint to the tensile strength σ _B 1' at the joint is 0.45 or less.
［ ９ ］
The method for producing a molded product according to any one of [ 1 ] to [ 8 ], wherein, when molding the second member, the first member is pulled in at least two directions parallel to a surface of the first member.

The present invention provides a molded article having excellent strength and appearance, and a manufacturing method thereof, which has a member containing continuous fiber reinforced resin and a member containing discontinuous fiber reinforced resin bonded to the surface of the member.

1 is a photograph showing one embodiment of a molded body according to the present invention. 1 is a cross-sectional photograph showing a joint of one embodiment of a molded body according to the present invention. 1 is a cross-sectional photograph showing a joint of one embodiment of a molded body according to the present invention. FIG. 2 is a perspective view showing a test piece used for measuring tensile strength in the examples and comparative examples.

The following is a detailed description of the embodiment of the present invention (hereinafter, referred to as the "present embodiment"). Note that the present invention is not limited to the following embodiment, and can be modified in various ways within the scope of the gist of the invention.

<Molded body>
The molded body of the present embodiment has a first member including a continuous fiber reinforced resin containing continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers, and is characterized in that at a joint between the first member and the second member, the first member is embedded in the second member, or the second member is embedded in the first member, and a ratio (t1/t) of a height t1 of the continuous reinforcing fibers at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00.
Fig. 1 is a photograph showing an example of a molded article of the present embodiment, which is a molded article in which a second member 2 serving as a rib is bonded to the surface of a first member 1.

In the molded article of the present embodiment, at a joint between a first member and a second member, the first member bites into the second member, or the second member bites into the first member. The joint refers to a portion (interface) where the first member and the second member are joined by thermal fusion.
The state where the first member is embedded in the second member at the joint means that the continuous fiber reinforced resin contained in the first member penetrates into the discontinuous fiber reinforced resin of the second member at the joint, and the continuous reinforcing fibers also penetrate into the discontinuous fiber reinforced resin along the resin of the continuous fiber reinforced resin. Therefore, the height t1 of the continuous reinforcing fibers at the joint is greater (higher) than the thickness t of the first member at the portion other than the joint.
In addition, the state where the second member is embedded in the first member at the joint means that the discontinuous fiber reinforced resin contained in the second member is embedded in the continuous fiber reinforced resin of the first member at the joint. Therefore, the height t1 of the continuous reinforcing fiber at the joint is smaller (lower) than the thickness t of the first member at the portion other than the joint. Note that the discontinuous reinforcing fiber may be embedded in the continuous fiber reinforced resin together with the resin of the discontinuous fiber reinforced resin.
2 and 3 are cross-sectional photographs in the thickness direction showing a joint in an example of the molded body of this embodiment. In the molded body of Fig. 2, the first member 1 is embedded in the second member 2, and in the molded body of Fig. 3, the second member 2 is embedded in the first member 1. The joint 3 is observed as a boundary line between the first member 1 and the second member 2.
The height t1 of the continuous reinforcing fiber at the joint refers to the thickness direction height of the continuous reinforcing fiber from the surface of the first member opposite to the surface where the second member is joined in a thickness direction cross section (e.g., see Figures 2 and 3) along the fiber direction of the continuous reinforcing fiber in the first member at the joint. When the first member is embedded in the second member at the joint (e.g., see Figure 2), the height t1 refers to the maximum value (the height of the part where the continuous reinforcing fiber is the highest) and when the second member is embedded in the first member at the joint (e.g., see Figure 3), the height t1 refers to the minimum value (the height of the part where the continuous reinforcing fiber is the lowest).

The molded article of the present embodiment can be suitably used for automobile parts such as oil pans, seat pans, pumps, cylinder head covers, gear boxes, and case parts, aircraft parts, railway parts, housing construction materials, robot parts, and the like.
The size and shape of the molded body of this embodiment can be various depending on the desired size and shape of the above-mentioned parts, etc.

<First member>
The first member constituting the molded body of the present embodiment includes a continuous fiber reinforced resin containing continuous reinforcing fibers, and is bonded to the second member on its surface. The first member may be made of only continuous fiber reinforced resin.
The size and shape of the first member are not particularly limited, and may be of various sizes and shapes depending on the size and shape of the desired molded body.
The form of the continuous reinforcing fiber is not particularly limited, but examples thereof include woven fabrics, knitted fabrics, unidirectional materials, and multiaxial woven fabrics. These may be used in a single layer or in a laminated form, or in combination with each other. The orientation of the continuous reinforcing fiber can be selected arbitrarily according to the strength required for the molded body, and examples thereof include uniaxial orientation at 0 degrees only, biaxial orientation at 0 degrees and 90 degrees, triaxial orientation at 0 degrees and ±30 degrees, and quadriaxial orientation at 0 degrees, ±45 degrees, and 90 degrees. From the viewpoint of uniformity of in-plane physical properties, multiple axes are preferred, and from the viewpoint of handleability, biaxial or quadriaxial orientation is more preferred. In the case of multiple axes, the amount of fibers oriented in each axis may be the same, or if strength in a specific direction is required, the amount of continuous reinforcing fibers oriented in that direction may be increased.

In the first member of this embodiment, the thickness t of the portion having the surface to be joined to the second member other than the joint with the second member is not particularly limited, and may be various thicknesses depending on the size and shape of the desired molded body, and does not have to be constant. From the viewpoints of moldability, strength and rigidity, and weight reduction, it is preferably 0.10 to 10.00 mm, more preferably 1.00 to 5.00 mm.
In addition, in the first member of this embodiment, the ratio (t1/t) of the height t1 of the continuous reinforcing fiber at the joint to the thickness t of the portion other than the joint with the second member in the portion having the surface to be joined with the second member is 0.50 to 2.00 or less, preferably 0.70 to 1.50, more preferably 0.90 to 1.00. When the ratio (t1/t) is 0.50 to 2.00, the penetration of the continuous reinforcing fiber in the first member into the second member, or the penetration of the discontinuous reinforcing fiber resin in the second member into the first member is small, and the twisting of the continuous reinforcing fiber is small, so that even when the molded body is used for a vehicle part or the like that is susceptible to external impact, the joint has sufficient strength to withstand the impact.
Examples of methods for controlling the ratio (t1/t) within the above range include a method of molding (joining) the second member by heating only the joining surface of the first member instead of the entire first member, reducing the pressure applied to the first member, adjusting the heating state to reduce fluidity, etc., thereby reducing the intrusion of the continuous reinforcing fibers of the first member into the cavity filled with the discontinuous fiber reinforced resin, thereby reducing the height t1 of the continuous reinforcing fibers at the joint. From the viewpoint of improving the balance with the adhesive strength σ _J at the joint between the first member and the second member described later, a method of molding (joining) the second member by heating only the joining surface of the first member instead of the entire first member is preferable.
The thickness t of the first member at the portion other than the joint is a value measured using a micrometer, and is the average value of the values obtained by measuring the thickness at at least five points. If the thickness of the first member at the portion other than the joint is not constant, the thickness t is the average value of the values measured at least at five points near the joint.
The height t1 of the continuous reinforcing fibers in the first member at the joint is a value measured by image analysis from a thickness direction cross-sectional photograph along the fiber direction of the continuous reinforcing fibers at the joint. The cross section is prepared so that the height of the second member relative to the surface of the first member is maximum. When the fibers are oriented in multiple directions, five cross sections are prepared along each fiber direction, and the average value is calculated by performing image measurement. When the first member is embedded in the second member at the joint, the maximum height in the fiber direction at which the average value is the largest is set to t1, and when the second member is embedded in the first member, the minimum height in the fiber direction at which the average value is the smallest is set to t1.

In the first member of this embodiment, the tensile strength in a direction along the surface of the first member, σ _B 1 in a portion other than the joint, is preferably 200 to 700 MPa, and more preferably 300 to 600 MPa, from the viewpoint of strength and rigidity.
In addition, in the first member of this embodiment, the tensile strength in the direction along the surface of the first member at the joint is preferably more than 150 MPa and not more than 650 MPa, and more preferably 200 to 600 MPa, from the viewpoint of strength and rigidity. The tensile strength σ _B1 ′ becomes higher as the bite of the first member into _the second member becomes smaller.
Furthermore, in the first member of this embodiment, the ratio of the tensile strength σ _B 1' to the tensile strength σ _B 1 (σ _B 1'/σ _B 1) is preferably 0.65 or more, more preferably 0.75 to 1.50, even more preferably 0.80 to 1.20, and most preferably 0.90 to 1.10. When the ratio (σ _B 1'/σ _B 1) is 0.65 or more, the strength of the first member is not significantly reduced by joining, and the molded body has sufficient strength to withstand impact even when used in vehicle parts that are susceptible to external impacts.
In this disclosure, the "direction along the surface of the first member" refers to the fiber orientation direction of the continuous reinforcing fibers in the first member. When the continuous reinforcing fibers in the first member are oriented in multiple directions, the tensile strength is measured in each direction, and the fiber orientation direction in which the tensile strength is maximum is referred to.
The tensile strengths σ _B 1 and σ _B 1′ are values measured in accordance with JIS K7165 at a test speed of 5 mm/min, and specifically, can be measured by the method described in the examples below.

Continuous fiber reinforced plastic
The continuous fiber reinforced resin contained in the molded article of this embodiment is a resin whose strength is increased by including continuous reinforcing fibers.
By selecting the type, amount, thickness, direction, etc. of the continuous reinforcing fibers used, as well as the type and amount of resin, etc. according to the purpose, the strength, impact resistance, etc. of the continuous fiber reinforced resin can be adjusted.

[Continuous reinforcing fiber]
The continuous reinforcing fibers contained in the continuous fiber reinforced resin of this embodiment may be those used as ordinary fiber reinforced composite materials, such as glass fibers, carbon fibers, aramid fibers, ultra-high strength polyethylene fibers, polybenzazole fibers, liquid crystal polyester fibers, polyketone fibers, metal fibers, ceramic fibers, etc. From the viewpoints of mechanical properties, thermal properties, and versatility, glass fibers, carbon fibers, and aramid fibers are preferred, and from the viewpoint of economy, glass fibers are preferred.
The continuous reinforcing fibers may be used alone or in combination of two or more.

When glass fibers are selected as the continuous reinforcing fibers, a sizing agent may be used, and the sizing agent preferably contains a silane coupling agent, a lubricant, and a binder.
The types of glass fibers and sizing agents used for glass fibers are not particularly limited, and known ones can be used. Specifically, for example, those described in JP 2015-101794 A can be used.

Similarly, when carbon fibers are selected as the continuous reinforcing fibers, a sizing agent may be used, and the sizing agent preferably contains a lubricant and a binder.
The type of sizing agent used for the carbon fibers is not particularly limited, and any known sizing agent can be used. Specifically, for example, the one described in JP 2015-101794 A can be used.

When using other continuous reinforcing fibers, the type and amount of sizing agent that can be used with glass fibers and carbon fibers can be appropriately selected and used depending on the characteristics of the continuous reinforcing fibers, and it is preferable to use a type and amount of sizing agent similar to that used with carbon fibers.

The continuous reinforcing fibers may be single or twisted yarns, or may be composite yarns made of two or more types of reinforcing fibers.
The reinforcing fibers may be in the form of threads, strings, braids, sheets (woven fabrics, knitted fabrics, unidirectionally aligned sheets, multiaxial woven fabrics, etc.), or the like.

The average fiber length of the reinforcing fibers is not particularly limited and can be various lengths depending on the size and shape of the desired molded article, but it is preferably longer than the length of the longest side of the molded article.
From the viewpoint of ease of handling, the number of single filaments of the reinforcing fiber is preferably 30 to 15,000.
From the viewpoint of ease of handling, the fineness of the reinforcing fibers is preferably 100 to 50,000 dtex.

The cross-sectional shape of the reinforcing fibers is not particularly limited, and may be any of a circular shape, an elliptical shape, an irregular shape (for example, a Y-shape, an X-shape, an I-shape, an R-shape, etc.), a hollow shape, and the like.
From the viewpoint of long-term properties, the average cross-sectional diameter of the reinforcing fibers is preferably 3 to 25 μm.
The average cross-sectional diameter of the reinforcing fibers can be measured using an optical microscope, a digital microscope, a scanning electron microscope (SEM), or the like.

The content of continuous reinforcing fibers in the continuous fiber reinforced resin is preferably 30 to 80% by mass, and more preferably 35 to 75% by mass.

[resin]
The resin contained in the continuous fiber reinforced resin of the present embodiment is not particularly limited as long as it does not impair the effects of the present invention, and may be a thermoplastic resin or a thermosetting resin, but is more preferably a thermoplastic resin.

-Thermoplastic resin-
The thermoplastic resin contained in the continuous fiber reinforced resin is not particularly limited, and examples thereof include polyolefin resins such as polyethylene and polypropylene; polyamide resins such as polyamide 6, polyamide 66, and polyamide 46; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate; polyacetal resins such as polyoxymethylene; polycarbonate resins; polyether ketone; polyether ether ketone; polyether sulfone; polyphenylene sulfide; thermoplastic polyetherimide; thermoplastic fluorine-based resins such as tetrafluoroethylene-ethylene copolymers, and modified thermoplastic resins obtained by modifying these. Among these thermoplastic resins, crystalline resins are preferred, such as polyolefin resins, polyamide resins, polyester resins, polyether ketones, polyether ether ketones, polyether sulfones, polyphenylene sulfide, thermoplastic polyetherimides, and thermoplastic fluorine resins, and from the viewpoints of mechanical properties and versatility, polyolefin resins, modified polyolefin resins, polyamide resins, and polyester resins are more preferred, and from the viewpoint of thermal properties, polyamide resins and polyester resins are even more preferred. Also, from the viewpoint of durability against repeated loads, polyamide resins are even more preferred, and polyamide 66 can be suitably used.
The above thermoplastic resins may be used alone or in combination of two or more.

--Polyamide resin--
The polyamide resin refers to a polymer compound having an -CO-NH- (amide) bond in the main chain. Examples of the polyamide resin include, but are not limited to, polyamides obtained by ring-opening polymerization of lactams, polyamides obtained by self-condensation of ω-aminocarboxylic acids, polyamides obtained by condensing diamines and dicarboxylic acids, and copolymers thereof.
The polyamide may be used alone or in combination of two or more kinds.
Regarding details of the other lactams, diamines (monomers), and dicarboxylic acids (monomers) described above, those described in JP-A-2015-101794 can be used as appropriate.

Specific examples of polyamides include polyamide 4 (poly-α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecane amide), polyamide 12 (polydodecanamide), polyamide 46 (polytetramethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610, polyamide 612, polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), and polyamide 6I (polyhexamethylene isophthalamide), as well as copolymer polyamides containing these as constituent components.

Examples of copolymer polyamides include copolymers of hexamethylene adipamide and hexamethylene terephthalamide, copolymers of hexamethylene adipamide and hexamethylene isophthalamide, and copolymers of hexamethylene terephthalamide and 2-methylpentanediamine terephthalamide.

- Polyester resin -
The polyester resin refers to a polymer compound having a -CO-O- (ester) bond in the main chain. Examples of the polyester resin include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6-naphthalenedicarboxylate.
Regarding details of other polyester-based resins, those described in JP-A-2015-101794 can be used as appropriate.

The continuous reinforcing fibers and thermoplastic resin contained in the continuous fiber reinforced resin of this embodiment can take the form of composite yarns such as mixed yarns containing continuous reinforcing fibers and thermoplastic resin fibers, coated yarns in which continuous reinforcing fibers are coated with thermoplastic resin, or impregnated yarns in which continuous reinforcing fibers are impregnated with thermoplastic resin.
From the viewpoint of ease of handling, the number of single filaments of the thermoplastic resin fiber is preferably 30 to 20,000.
From the viewpoint of ease of handling, the fineness of the thermoplastic resin fiber is preferably 100 to 50,000 dtex.

- Thermosetting resin -
The thermosetting resin is not particularly limited, and examples thereof include epoxy resins, thermosetting modified polyphenylene ether resins, thermosetting polyimide resins, urea resins, allyl resins, silicon resins, benzoxazine resins, phenolic resins, unsaturated polyester resins, bismaleimide triazine resins, alkyd resins, furan resins, melamine resins, polyurethane resins, aniline resins, other industrially available resins, and resins obtained by mixing two or more of these resins.

The content of continuous fiber reinforced resin in the molded body is preferably 20 to 90 mass%, more preferably 30 to 80 mass%, and even more preferably 40 to 70 mass%.

<<Method for producing continuous fiber reinforced resin>>
The continuous fiber reinforced resin can be produced, for example, by a method of heating and pressurizing a laminate of a film-like resin and a sheet-like (woven fabric, knitted fabric, unidirectionally aligned sheet, multiaxially woven fabric, etc.) reinforcing fiber, or a method of heating and pressurizing a sheet (woven fabric, knitted fabric, unidirectionally aligned sheet, multiaxially woven fabric, etc.) made of a fibrous resin (resin fiber) and reinforcing fiber. The sheet made of resin fiber and reinforcing fiber may be produced using a mixed fiber yarn of the resin fiber and the reinforcing fiber, a coated yarn, an impregnated yarn, or the like.
The above-mentioned heating and pressurizing treatment includes, for example, placing the material in a mold, heating the mold to a temperature equal to or higher than the melting point or glass transition temperature of the resin, and then clamping the mold with a clamping force of 1 to 100 MPa to perform compression molding. The molding time is 1 to 30 minutes after the melting point or glass transition temperature of the resin is reached, and the mold is cooled to a temperature between the melting point or glass transition temperature of the resin minus 200°C and the melting point or glass transition temperature of the resin minus 10°C, and then opened to obtain a continuous fiber reinforced resin.

<Second member>
The second member constituting the molded body of the present embodiment includes a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers, and is bonded to the first member on the surface of the first member. The second member may be made of only discontinuous fiber reinforced resin.
The second member is not joined to the entirety of any surface of the first member, but is intermittently disposed on and joined to any surface of the first member.
The size and shape of the second member are not particularly limited, and may be various sizes and shapes depending on the size and shape of the desired molded body, etc. For example, the second member may have a shape such as a rib (lattice-shaped, radial, circular, wavy, etc.) or a boss (cylindrical, columnar, conical, etc.).

In the second member of this embodiment, the height H of the joint with the first member is not particularly limited and may be various heights depending on the size and shape of the desired molded product, and does not have to be constant. From the viewpoint of the reinforcing effect of the molded product, it is preferably 5 to 300 mm, more preferably 10 to 200 mm.
The height H of the second member is a value measured using a micrometer.

In the second member of this embodiment, the width W of the joint with the first member is not particularly limited and may be various depending on the size and shape of the desired molded body, and does not have to be constant. From the viewpoint of joint strength, it is preferably 3 to 50 mm, more preferably 5 to 40 mm.
In addition, in the second member of this embodiment, the ratio ((t1-t)/W) of the difference t1-t obtained by subtracting the thickness t of the first member in the portion other than the joint from the height t1 of the continuous reinforcing fibers in the first member in the joint to the width W of the second member in the joint is preferably -0.50 to 10.00, and when the width W is not constant, the ratios ((t1-t)/W) calculated in both the portion with the smallest width W and the portion with the largest width W are preferably both -0.50 to 10.00. The above ratio is more preferably 1.00 to 9.00, and even more preferably 2.00 to 8.00. When the ratio ((t1-t)/W) is -0.50 to 10.00, the penetration of the continuous reinforcing fibers in the first member into the second member, or the penetration of the discontinuous reinforcing fiber resin in the second member into the first member is small, and twisting of the continuous reinforcing fibers is small. Therefore, even when the molded body is used in a vehicle part or the like that is susceptible to external impacts, the joint has sufficient strength to withstand the impact.
Methods for controlling the ratio ((t1-t)/W) within the above range include, for example, heating only the joining surface of the first member rather than the entire first member to mold (join) the second member, reducing the pressure applied to the first member, etc., thereby reducing the penetration of the continuous reinforcing fibers of the first member into the cavity filled with the discontinuous fiber reinforced resin, thereby reducing the height t1 of the continuous reinforcing fibers in the first member at the joint (i.e., reducing t1-t).
The width W of the second member is a value measured using a micrometer.

In the second member of this embodiment, the tensile strength σ _B 2 in the portion other than the joint in the direction along the surface of the second member is preferably 50 to 300 MPa, and more preferably 80 to 280 MPa, from the viewpoint of strength and rigidity.
In this disclosure, the term "direction along the surface of the second member" means a direction passing through a point on the side surface of the second member (if the side surface is a curved surface, the tangent direction of the point on the side surface) perpendicular to the longitudinal direction of the second member (if there are multiple directions, select any one of them). When the second member is in a shape extending along at least one direction on the surface of the first member where the second member is joined to the second member, the longitudinal direction of the second member is the direction connecting the width center of one end of the extension and the width center of the other end. When it is difficult to determine the extension direction of the second member (when the second member is columnar or pyramidal, etc.), the direction connecting two points that are the greatest distance between any two points on the intersection line between the first member and the second member (i.e., the contour line of the joint) (if there are multiple directions, any one of them may be selected, but if there is a direction perpendicular to the direction of the continuous reinforcing fibers in the first member, it is preferable to select that direction) is the longitudinal direction of the second member.
The tensile strength σ _B 2 is a value measured in accordance with JIS K7165 at a test speed of 5 mm/min, and specifically, can be measured by the method described in the examples below.

In addition, the first member and the second member of this embodiment preferably have an adhesive strength σ _J at the joint of 5 to 200 MPa, and more preferably 10 to 150 MPa, from the viewpoint of strength and rigidity.
Furthermore, in the molded article of this embodiment, the ratio of the adhesive strength σ _J to the tensile strength σ _B 1' at the joint (σ _J /σ _B 1') is preferably 0.45 or less, more preferably 0.01 to 0.40, even more preferably 0.02 to 0.35, and still more preferably 0.02 to 0.20. When the ratio (σ _J /σ _B 1') is 0.45 or less, the joint has sufficient strength to withstand impact even when the molded article is used in a vehicle part or the like that is susceptible to external impact.
The adhesive strength _σJ is a value measured at a test speed of 5 mm/min, and specifically, can be measured by the method described in the examples below.

<Discontinuous fiber reinforced plastic>
The discontinuous fiber reinforced resin contained in the molded article of this embodiment is a resin whose strength is increased by including discontinuous reinforcing fibers.
By selecting the type, amount, thickness, direction, etc. of the discontinuous reinforcing fibers used, as well as the type and amount of the resin, according to the purpose, the strength and impact resistance of the discontinuous fiber reinforced resin can be adjusted.

Discontinuous fiber reinforced resin differs from continuous fiber reinforced resin in that the reinforcing fibers in the resin also flow when melted, allowing the resin to flow into the fine details of the complex shape of the mold when molding a molded article, making it possible to form parts of the complex shape of the molded article.
Furthermore, in the molded body of this embodiment, when the discontinuous fiber reinforced resin is bonded to both at least a portion of the metal and at least a portion of the continuous fiber reinforced resin, the bonding between the metal and the continuous fiber reinforced resin is strengthened, resulting in a molded body with high strength.

[Discontinuous reinforcing fibers]
The discontinuous reinforcing fibers contained in the discontinuous fiber reinforced resin of this embodiment may be randomly dispersed in the resin, or may be configured as a randomly oriented material (such as a nonwoven fabric) having randomly oriented discontinuous fibers.

The discontinuous reinforcing fibers may be short fibers, long fibers, or random fibers.
The average fiber length of the discontinuous reinforcing fibers is preferably 0.05 to 20 mm, more preferably 0.10 to 15 mm, and even more preferably 0.15 to 10 mm.
In particular, when the second member is molded by injection molding a discontinuous fiber reinforced resin, the average fiber length of the discontinuous reinforcing fibers is preferably less than 3 mm, more preferably 0.01 to 2.5 mm, even more preferably 0.05 to 2.0 mm, and even more preferably 0.10 to 1.5 mm. If the average fiber length of the discontinuous reinforcing fibers is less than 3 mm, the fluidity of the discontinuous fiber reinforced resin is good during injection molding, and not only the resin but also the discontinuous reinforcing fibers flow into the details of the complex shape of the mold, so that a molded body having a complex shape but high strength can be produced.
In particular, when the second member is molded by press molding a discontinuous fiber reinforced resin, the average fiber length of the discontinuous reinforcing fibers is preferably 3 mm or more, more preferably 5 to 60 mm, even more preferably 10 to 45 mm, and even more preferably 15 to 40 mm. When the average fiber length of the discontinuous reinforcing fibers is 3 mm or more, a molded body with high strength can be produced.
The average fiber length of the discontinuous reinforcing fibers is the average value of the lengths of the discontinuous reinforcing fibers remaining after the molded body is incinerated.

The types of the discontinuous reinforcing fibers include the same as those of the continuous reinforcing fibers described above, and may be the same as or different from the continuous reinforcing fibers.
The discontinuous reinforcing fibers may be used alone or in combination of two or more.

The content of discontinuous reinforcing fibers in the discontinuous fiber reinforced resin is preferably 30 to 80% by mass, and more preferably 35 to 75% by mass.

[resin]
The resin contained in the discontinuous fiber reinforced resin of this embodiment is not particularly limited as long as it does not impair the effects of the present invention, and may be a thermoplastic resin or a thermosetting resin, but is more preferably a thermoplastic resin.

-Thermoplastic resin-
The type of thermoplastic resin contained in the discontinuous fiber reinforced resin includes the same as the thermoplastic resin contained in the continuous fiber reinforced resin described above, and may be the same as or different from the thermoplastic resin contained in the continuous fiber reinforced resin.
The above thermoplastic resins may be used alone or in combination of two or more.

- Thermosetting resin -
The type of thermosetting resin contained in the discontinuous fiber reinforced resin includes the same as the thermosetting resin contained in the continuous fiber reinforced resin described above, and may be the same as or different from the thermosetting resin contained in the continuous fiber reinforced resin.
The above thermosetting resins may be used alone or in combination of two or more.

The content of discontinuous fiber reinforced resin in the molded body is preferably 10 to 90 mass%, more preferably 20 to 80 mass%, and even more preferably 30 to 70 mass%.

<<Method for producing discontinuous fiber reinforced resin>>
Discontinuous fiber reinforced resin can be produced, for example, by a method of kneading and dispersing reinforcing fibers in a resin, or by a method of heating and pressurizing a laminate of a film-like resin and a sheet-like (nonwoven fabric, etc.) reinforcing fiber.
The above-mentioned heating and pressurizing treatment includes, for example, placing the material in a mold, heating the mold to a temperature equal to or higher than the melting point or glass transition temperature of the resin, and then clamping the mold with a clamping force of 1 to 100 MPa to perform compression molding. The molding time is 1 to 30 minutes after the melting point or glass transition temperature of the resin is reached, and the mold is cooled to a temperature between the melting point or glass transition temperature of the resin minus 200°C and the melting point or glass transition temperature of the resin minus 10°C, and then opened to obtain a discontinuous fiber reinforced resin.

[Additive]
The molded article of the present embodiment may contain additives as necessary. The molded article of the present embodiment may contain additives such as, for example, an antiaging agent, an antioxidant, a weathering agent, a metal deactivator, a light stabilizer, a heat stabilizer, an ultraviolet absorber, an antibacterial/antifungal agent, an odor control agent, an electrical conductivity imparting agent, a dispersant, a softener, a plasticizer, a crosslinking agent, a co-crosslinking agent, a vulcanizing agent, a vulcanizing assistant, a foaming agent, a foaming assistant, a colorant, a flame retardant, a vibration damping agent, a nucleating agent, a neutralizing agent, a lubricant, an antiblocking agent, a dispersing agent, a flowability improving agent, and a mold release agent.
The content of the additive may be 10% by mass or less based on 100% by mass of the molded body.

<Method of manufacturing molded body>
One aspect of the method for producing a molded body of the present embodiment is characterized in that it includes heating a continuous fiber reinforced resin containing continuous reinforcing fibers, placing it in a mold for a molded body, clamping the mold to mold a first member, and molding a second member in the mold for a molded body using a discontinuous fiber reinforced resin containing heated discontinuous reinforcing fibers.

In the above-described manufacturing method, the continuous fiber reinforced resin is heated and then placed in a mold for molding, and the mold is clamped to mold the first member.
The method of heating the continuous fiber reinforced resin before placing it in the mold for molding is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method of heating in a mold separate from the mold for molding, etc. The heating temperature of the continuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.
The temperature of the mold for molding is preferably set to a temperature equal to or higher than the glass transition temperature of the fiber-reinforced resin and is preferably controlled to a constant temperature. The mold clamping force during molding of the first member is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

In the above manufacturing method, the second component is molded after the first component, so sufficient pressure can be applied when molding the first component, and even if the shape of the first component is complex, it can be molded well down to the finest details. In addition, by not removing the molded first component from the mold for molding, the molding cycle can be shortened.

In the above manufacturing method, the method for molding the second component using discontinuous fiber reinforced resin is preferably injection molding. Injection molding allows the discontinuous fiber reinforced resin to flow more effectively into the fine details of the complex shape of the mold, even when the shape of the second component is complex.

When the second member is injection molded, the timing of injection and filling of the discontinuous fiber reinforced resin is preferably within 30 seconds from the clamping of the continuous fiber reinforced resin.
As injection conditions, it is preferable to set the cylinder temperature of the injection unit to 270 to 320° C., the filling pressure to 1 to 150 MPa, the injection speed to 5 to 150 mm/sec, and the holding pressure to 3 to 200 MPa.
After the discontinuous fiber reinforced resin is injected and filled, the first member and the second member are joined by holding for 1 to 180 minutes. The temperature of the mold for molding at this time is preferably set to a temperature equal to or higher than the glass transition temperature and lower than the melting point of the fiber reinforced resin, and is always controlled at a constant temperature. In particular, when the fiber reinforced resin is polyamide 66, the temperature is preferably set to the glass transition temperature + 10 to 80°C. The mold clamping force at this time is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

Another aspect of the method for producing a molded body of this embodiment is characterized in that it includes heating a continuous fiber reinforced resin containing continuous reinforcing fibers, placing it in a mold for a molded body, clamping the mold to mold a first member, heating the joining side surface of the portion of the first member to which the second member is to be joined or the entire joining side surface including the joining side surface in the mold for a molded body, and then molding the second member using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.

In the above-described manufacturing method, the continuous fiber reinforced resin is heated and then placed in a mold for molding, and the mold is clamped to mold the first member.
The method of heating the continuous fiber reinforced resin before placing it in the mold for molding is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method of heating in a mold separate from the mold for molding, etc. The heating temperature of the continuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.
The temperature of the mold for molding is preferably set to a temperature equal to or higher than the glass transition temperature of the fiber-reinforced resin and is preferably controlled to a constant temperature. The mold clamping force during molding of the first member is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.
After clamping, the temperature of the mold for molding is lowered to a temperature equal to or lower than the glass transition temperature of the continuous fiber reinforced resin to cool and solidify the first member, and then the mold for molding is opened.

In the above manufacturing method, since the second member is molded after the first member is molded, sufficient pressure can be applied when the first member is molded, and even if the first member has a complex shape, it can be molded well down to the fine details. In addition, the molded first member can be heated in the mold for molding without being removed from the mold for molding, thereby shortening the molding cycle.
In addition, in the above manufacturing method, the joining side surface (part to be a joint) of the part of the first member to which the second member is joined or the entire joining side surface of the first member including the joining side surface (part to be a joint) is heated, so that the surface of the first member to which the second member (discontinuous fiber reinforced resin) is joined is in a molten state, and the adhesion between the first member and the second member can be increased. At this time, by heating only the surface of the first member rather than the entire first member, even if a high pressure is applied to the first member in the mold clamping direction, it is possible to reduce the intrusion of the continuous reinforcing fibers of the first member into the cavity filled with the discontinuous fiber reinforced resin (particularly into the cavity provided intermittently), so that the above-mentioned ratios (t1/t) and ((t1-t)/W) can be controlled within the above-mentioned specific ranges. In addition, since the surface of the first member other than the surface to be joined is not heated, a molded body with excellent appearance is obtained.
The method for heating the first member in the mold for forming a compact is not particularly limited, and examples of the method include a method using an IR heater, a laser, hot air (heated steam), a burner, or the like.

In the above manufacturing method, the method for molding the second component using discontinuous fiber reinforced resin is preferably injection molding. Injection molding allows the discontinuous fiber reinforced resin to flow more effectively into the fine details of the complex shape of the mold, even when the shape of the second component is complex.

When the second member is injection molded, the timing for injecting and filling the discontinuous fiber reinforced resin is preferably within 30 seconds after the surface of the first member is heated and the mold for molding is closed.
As injection conditions, it is preferable to set the cylinder temperature of the injection unit to 270 to 320° C., the filling pressure to 1 to 150 MPa, the injection speed to 5 to 150 mm/sec, and the holding pressure to 3 to 200 MPa.
After the discontinuous fiber reinforced resin is injected and filled, the first member and the second member are joined by holding for 1 to 180 minutes. The temperature of the mold for molding at this time is preferably set to a temperature equal to or higher than the glass transition temperature and lower than the melting point of the fiber reinforced resin, and is always controlled at a constant temperature. In particular, when the fiber reinforced resin is polyamide 66, the temperature is preferably set to the glass transition temperature + 10 to 80°C. The mold clamping force at this time is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

Another aspect of the manufacturing method of the molded body of this embodiment is characterized in that it includes heating a continuous fiber reinforced resin containing continuous reinforcing fibers, placing it in a mold for a first member, clamping the mold to mold the first member, removing the first member from the mold for the first member, heating the joining side surface of the portion of the first member to which the second member is to be joined or the entire joining side surface including the joining side surface, placing the heated first member in a mold for a molded body, and molding the second member using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.

In the above-described manufacturing method, the continuous fiber reinforced resin is heated and then placed in a mold for the first member, and the mold is clamped to mold the first member.
The method of heating the continuous fiber reinforced resin before placing the first member mold is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method of heating in a mold separate from the first member mold, etc. The heating temperature of the continuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.
The temperature of the mold for the first member is preferably set to a glass transition temperature of the fiber-reinforced resin or higher and is preferably always kept constant. The mold clamping force during molding of the first member is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.
After clamping, the temperature of the mold for the first member is lowered to below the glass transition temperature of the continuous fiber reinforced resin to cool and solidify the first member, and then the mold for the first member is opened and the first member is demolded.

In the above manufacturing method, since the second member is molded after the first member is molded, sufficient pressure can be applied during molding of the first member, and even if the shape of the first member is complex, it can be molded well down to the smallest details. In particular, by molding in a mold for the first member that does not have a cavity for filling discontinuous fiber reinforced resin, the smoothness of each surface of the first member and the accuracy of the thickness are higher. In addition, by cooling and solidifying the first member and releasing it from the mold, the shape of the first member is fixed, making it easier to transport the first member to the mold for the molded body and to position it when installing it in the mold for the molded body.
Also, in the above manufacturing method, by heating the joining side surface (part to be the joining part) of the first member to which the second member is joined or the entire joining side surface of the first member including the joining side surface (part to be the joining part), the surface of the first member to which the second member (discontinuous fiber reinforced resin) is joined is in a molten state, and the adhesion between the first member and the second member can be increased. At this time, by heating only the surface of the first member rather than the entire first member, even if a high pressure is applied to the first member in the mold clamping direction, it is possible to reduce the intrusion of the continuous reinforcing fibers of the first member into the cavity filled with the discontinuous fiber reinforced resin (particularly into the cavity provided intermittently), so that the above-mentioned ratios (t1/t) and ((t1-t)/W) can be controlled within the above-mentioned specific ranges. In addition, since the surface of the first member other than the surface to be joined is not heated, a molded body with excellent appearance is obtained.
The method for heating the first member in the mold for forming a compact is not particularly limited, and examples of the method include a method using an IR heater, a laser, hot air (heated steam), a burner, or the like.

In the above manufacturing method, the method of molding the second member using discontinuous fiber reinforced resin may be either injection molding or press molding. When the shape of the second member is complex, injection molding is preferred because it allows the discontinuous fiber reinforced resin to flow more effectively into the fine details of the complex shape of the mold. Furthermore, from the viewpoint of increasing the strength of the second member, press molding is preferred because it allows the use of discontinuous fiber reinforced resin containing discontinuous reinforcing fibers with longer fiber lengths.

The method and conditions for injection molding the second component may be the same as those described above.

When the second member is press molded, it is preferable to place the heated discontinuous fiber reinforced resin within 30 seconds after the surface of the first member is heated.
The method for heating the discontinuous fiber reinforced resin is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method for heating in a mold separate from the mold for the molded body, etc. The heating temperature of the discontinuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.
After the discontinuous fiber reinforced resin is placed, the first member and the second member are joined by holding the discontinuous fiber reinforced resin for 0.1 to 3 minutes. The temperature of the mold for molding is preferably set to a temperature equal to or higher than the glass transition temperature and lower than the melting point of the fiber reinforced resin, and is always controlled at a constant temperature. In particular, when the fiber reinforced resin is polyamide 66, the temperature is preferably set to the glass transition temperature + 10 to 80°C. The mold clamping force is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

Another aspect of the manufacturing method of the molded body of the present embodiment is characterized in that it includes placing a continuous fiber reinforced resin containing heated continuous reinforcing fibers and a heated discontinuous fiber reinforced resin in a mold for a molded body, and clamping the mold to mold a first member and a second member.
In the above manufacturing method, the heated discontinuous fiber reinforced resin and the heated continuous fiber reinforced resin are simultaneously placed in a mold and press molded, so that even when a second member having a complex shape is formed using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers with long fiber length, it is possible to mold the second member well down to the fine details. In addition, by simultaneously press molding the heated discontinuous fiber reinforced resin and the heated continuous fiber reinforced resin, it is possible to increase the adhesion between the first member and the second member and shorten the molding cycle.
The method for heating the continuous fiber reinforced resin and the discontinuous fiber reinforced resin is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method of heating in a mold separate from the mold for the molded body, etc. The heating temperature of the continuous fiber reinforced resin and the discontinuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.
After the continuous fiber reinforced resin and the discontinuous fiber reinforced resin are placed, they are held for 0.1 to 3 minutes to bond the continuous fiber reinforced resin (first member) and the discontinuous fiber reinforced resin (second member). The temperature of the mold for molding is preferably set to a temperature equal to or higher than the glass transition temperature and lower than the melting point of the fiber reinforced resin, and is always controlled at a constant temperature. In particular, when the fiber reinforced resin is polyamide 66, the temperature is preferably set to a glass transition temperature + 10 to 80°C. The mold clamping force is preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

Another aspect of the method for producing a molded body according to this embodiment is characterized in that it includes heating a continuous fiber reinforced resin containing continuous reinforcing fibers, placing the resin in a mold for a molded body, clamping the mold with a clamping force such that the pressure applied to the continuous fiber reinforced resin in the clamping direction is 10 MPa or less to mold a first member, and then molding a second member using the heated discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.

In the above-described manufacturing method, the continuous fiber reinforced resin is heated and then placed in a mold for molding, and the mold is clamped to mold the first member.
The method of heating the continuous fiber reinforced resin before placing it in the mold for molding is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method of heating in a mold separate from the mold for molding, etc. The heating temperature of the continuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.

The clamping force of the mold for the molded body is set so that the pressure applied to the continuous fiber reinforced resin in the clamping direction is 10 MPa or less. If the pressure applied to the continuous fiber reinforced resin in the clamping direction is high, the continuous reinforcing fibers will tend to penetrate into the cavity filled with the discontinuous fiber reinforced resin when it is joined to the second member (discontinuous fiber reinforced resin), but if the pressure is 10 MPa or less, the penetration of the continuous reinforcing fibers can be reduced. Therefore, the above-mentioned ratios (t1/t) and ((t1-t)/W) can be controlled to be within the above-mentioned specific ranges.

In the above manufacturing method, the method of molding the second member using discontinuous fiber reinforced resin may be either injection molding or press molding. When the shape of the second member is complex, injection molding is preferred because it allows the discontinuous fiber reinforced resin to flow more effectively into the fine details of the complex shape of the mold. Furthermore, from the viewpoint of increasing the strength of the second member, press molding is preferred because it allows the use of discontinuous fiber reinforced resin containing discontinuous reinforcing fibers with longer fiber lengths.

When the second member is injection molded, the timing of injection and filling of the discontinuous fiber reinforced resin is preferably within 30 seconds from the clamping of the continuous fiber reinforced resin.
As injection conditions, it is preferable to set the cylinder temperature of the injection unit to 270 to 320° C., the filling pressure to 1 to 150 MPa, the injection speed to 5 to 150 mm/sec, and the holding pressure to 5 to 200 MPa.
After the discontinuous fiber reinforced resin is injected and filled, the first member and the second member are joined by holding for 0.1 to 3 minutes. The temperature of the mold for the molded body at this time is set to a temperature equal to or lower than the glass transition temperature of the fiber reinforced resin, and is preferably controlled to a constant temperature at all times. The mold clamping force at this time is set so that the pressure applied to the first member in the mold clamping direction is 10 MPa or less, preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

When the second member is press molded, it is preferable to place the heated discontinuous fiber reinforced resin within 30 seconds after the continuous fiber reinforced resin is clamped in the mold.
The method for heating the discontinuous fiber reinforced resin is not particularly limited, and examples thereof include a method using an IR heater, a heating furnace, a preheating roll, etc., a method for heating in a mold separate from the mold for the molded body, etc. The heating temperature of the continuous fiber reinforced resin is preferably equal to or lower than the decomposition temperature of the resin.
After the discontinuous fiber reinforced resin is placed, the first member and the second member are joined by holding the resin for 0.1 to 3 minutes. The temperature of the mold for the molded body is preferably set to a temperature equal to or higher than the glass transition temperature of the fiber reinforced resin and is always kept constant. The clamping force is set so that the pressure applied to the first member in the clamping direction is 10 MPa or less, preferably 0.01 to 20 MPa, more preferably 0.1 to 15 MPa.

In any of the above aspects of the manufacturing method of the molded body of this embodiment, the thickness of the first member may be approximately equal to the height of the cavity corresponding to the shape of the first member in the molded body die. In this way, by making the height of the cavity corresponding to the shape of the first member in the molded body die (the gap (clearance) of the cavity) approximately equal to the thickness of the first member before molding (joining) the second member, the pressure applied to the first member can be reduced, the continuous reinforcing fibers of the first member can be reduced from being cut into the cavity filled with the discontinuous fiber reinforced resin, and the height t1 of the continuous reinforcing fibers at the joint of the first member can be reduced.
In addition, "the thickness of the first member and the height of the cavity in the mold for the molded body corresponding to the shape of the first member are approximately equal" may mean that the height of the cavity in the mold for the molded body corresponding to the shape of the first member is ±25% of the thickness of the first member before the second member is molded (joined).

In addition, in any of the above aspects of the manufacturing method of the molded body of the present embodiment, when molding the first member and/or the second member, the first member may be pulled in at least two directions parallel to the joining surface of the first member. By pulling in this manner, it is possible to prevent wrinkles from being formed on the joining surface of the first member and to further reduce the intrusion of the continuous reinforcing fibers of the first member into the cavity filled with the discontinuous fiber reinforced resin (particularly into the cavity provided intermittently).
The tensile force applied during the above tensioning is preferably 0.1 to 10 MPa.
The at least two directions parallel to the joining side surface of the first member preferably include a direction parallel to and a direction perpendicular to the direction of the continuous reinforcing fibers in the first member.

In any of the above aspects of the mold used in the manufacturing method of the molded body of this embodiment, it is preferable that the taper angle of the recess is 0.5 to 15°.

In addition, from the viewpoint of designing the molded body, in any of the above manufacturing methods, it is preferable that the difference in thickness between before and after molding of the first member (the difference between the thickness of the raw material continuous fiber reinforced resin and the thickness of the first member after molding) is small, that is, the change in thickness is small. More specifically, the thickness of the first member after molding is preferably 80 to 120%, more preferably 95 to 105%, and even more preferably 99 to 101%, with the thickness of the first member before molding (the thickness of the continuous fiber reinforced resin) being 100%.
Methods for reducing the difference in thickness before and after molding of the first member (reducing the change in thickness) include, for example, a method of heating only one side of the material in an IR heating furnace during molding, a method of lowering the heating temperature so that the entire material is not heated and melted, a method of increasing the heating temperature to heat and melt the entire material and then using press pressure to return the material to the thickness before molding, and a method of increasing the press pressure.

The present invention will be described in more detail below with reference to examples , reference examples and comparative examples, although the present invention is not limited to these examples.

<Measurement method>
The measurement methods used in the examples , reference examples and comparative examples are as follows.

(1) Thickness of the first member, width and height of the second member The thickness t (mm) of the first member of the molded body obtained in the examples , reference examples and comparative examples was measured at the portion other than the joint using a micrometer (Mitutoyo MDC-25SX). In addition, the height t1 (mm) of the continuous reinforcing fiber in the first member at the joint was obtained by image analysis of a thickness direction cross-sectional photograph (taken using Keyence VHX-5000) along the fiber direction of the continuous reinforcing fiber at the joint.
The thickness t was the average value of the values measured at five points. When the thickness was not uniform in the portion other than the joint, the thickness t was the average value of the values measured at at least five points near the joint.
In addition, t1 was measured by preparing a cross section in the thickness direction along the fiber direction of the continuous reinforcing fiber at the joint and using image analysis from a cross section photograph. The cross section was prepared so that the height of the second member relative to the surface of the first member was maximized. When the fibers were oriented in multiple directions, five cross sections were prepared along each fiber, and the average value measured using image analysis from the cross section photograph was calculated. When the first member was biting into the second member at the joint, the maximum height in the fiber direction at which the average value was the largest was taken as t1, and when the second member was biting into the first member, the minimum height in the fiber direction at which the average value was the smallest was taken as t1.
For the second members of the molded articles obtained in the Examples , Reference Examples, and Comparative Examples, the width W (mm) and height H (mm) at the joint were measured using a micrometer (MDC-25SX, manufactured by Mitutoyo Corporation).

(2) Tensile strength of first member and second member For the first member of the molded body obtained in the Examples , Reference Examples , and Comparative Examples, the tensile strength σ _B 1 (MPa) in the portion other than the joint in the direction along the surface of the first member (the direction of the black arrow in FIG. 4) and the tensile strength _{σ B} 1' (MPa) in the joint were measured. A test piece of 100 mm length x 10 mm width not including the second member (joint) and a test piece of 100 mm length x 100 mm width having the second member (joint) at the horizontal center (FIG _. 4) were cut out from the first member of the molded body and used for measuring the tensile strength σ B 1 and σ B 1'.
For the second members of the molded bodies obtained in the Examples , Reference Examples, and Comparative Examples, the tensile strength σB2 (MPa) was measured in the direction along the surface of the second member (the direction of the white arrow in Figure 4) at the portion other than the joint. A test piece having a height of 20 mm and a length of 20 mm, not including the joint _, was cut out from the second member of the molded body and used for measuring the tensile strength _σB2 .
The tensile strength was measured using a universal testing machine manufactured by Instron Corporation in accordance with JIS K7165 at a test speed of 5 mm/min.

(3) Adhesive strength of joint For the molded articles obtained in the Examples , Reference Examples , and Comparative Examples, the adhesive strength σ _J (MPa) of the joint in the direction along the surface of the second member (the direction of the white arrow in FIG. 4 ) was measured at a test speed of 5 mm/min using a universal testing machine manufactured by Instron Corp. For the measurement, a test piece measuring 100 mm long x 100 mm wide and having the second member (joint) at the horizontal center was cut out from the first member of the molded article.

<Ingredients>
The materials used in the examples , reference examples and comparative examples are as follows.

[Continuous fiber reinforced plastic]
Continuous fiber reinforced resin X: Continuous fiber reinforced resin X was produced as follows.
(Continuous reinforcing fiber)
Glass fiber (ER1200T-423, manufactured by Nippon Electric Glass Co., Ltd.)
(Thermoplastic resin)
Polyamide resin A: Polyamide 66 ("Leona 1502S" manufactured by Asahi Kasei Corporation) and carbon black master batch ("LC050M-33943-M" manufactured by Asahi Kasei Corporation) dry blended in a mass ratio of 4:1 (production of glass cloth)
The glass fibers were used as warp and weft yarns in a rapier loom (weaving width: 2 m) to produce a glass cloth. The weaving form of the obtained glass cloth was a twill weave, the weaving density was 6.5 threads/25 mm, and the basis weight was 600 g/ ^m2 .
<Production of polyamide resin film>
The polyamide resin A was molded using a T-die extrusion molding machine (manufactured by Soken Co., Ltd.) to obtain a film having a thickness of 200 μm.
<Production of Continuous Fiber Reinforced Resin X>
A molding machine (a hydraulic molding machine with a maximum clamping force of 50 tons, manufactured by Shoji Co., Ltd.) and a mold for a flat plate (length 250 mm x width 390 mm x thickness 2 mm) with a spigot structure were prepared.
Six pieces of glass cloth and seven pieces of polyamide resin A film obtained above were cut to fit the shape of a mold, and the glass cloth and the film of polyamide resin A were alternately stacked (in the order A/G/A/G/A/G/A/G/A/G/A/G/A, A is the film of polyamide resin A and G is the glass cloth) so that the film of polyamide resin A was on the surface, and placed in the mold. The glass cloth was arranged so that all fiber orientations (warp and weft directions) were aligned with the vertical and horizontal directions of the mold.
The molding machine was heated so that the hot plate temperature reached 330° C., and then the mold was clamped at a clamping force of 5 MPa to perform compression molding. The molding time was set to 1 minute after the temperature reached 265° C., which is the melting point of polyamide 66, and the mold was rapidly cooled to 100° C. and then opened to obtain a continuous fiber reinforced resin X (length 250 mm × width 390 mm × thickness about 2 mm).

[Discontinuous fiber reinforced plastic]
Discontinuous fiber reinforced resin Y: short glass fiber reinforced polyamide 66 ("Leona 14G50" manufactured by Asahi Kasei Corporation, glass fiber: 50 mass%, average fiber length 0.5 mm)
Discontinuous fiber reinforced resin Z: Glass fiber reinforced polyamide 6 ("TEPEX flowcore 102" manufactured by LANXESS, glass fiber: 55 mass%, average fiber length 40 mm)

[Example 1]
Continuous fiber reinforced resin X, both sides of which had been heated to 300°C in a double-sided IR heating furnace, was placed at a predetermined position in a molded body press die at 120°C with a cavity height of 2 mm corresponding to the shape of the first member, and pressed with a clamping force of 5 MPa to mold a first member (thickness 2.35 mm). Immediately after that, discontinuous fiber reinforced resin Y was injected from the injection unit into the cavity of the molded body press die corresponding to the shape of the second member at a cylinder set temperature of 290°C, injection pressure of 150 MPa, injection speed of 100 mm/sec, and holding pressure of 100 MPa to mold the second member.
By holding for 1 minute, the first member and the second member were cooled and solidified, and the mold was opened and demolded to obtain a molded body having the shape shown in FIG. 1 (first member: length 250 mm x width 390 mm x thickness t 2.35 mm, second member: width W 3.5 mm x height H 17 mm). The taper angle of the recessed side of the press mold for the molded body was 3°. The fiber orientation (warp and weft directions) of the first member was made to coincide with the longitudinal direction of the second member.
The physical properties of the obtained molded product are shown in Table 1.

[Example 2]
A molded body was obtained in the same manner as in Example 1, except that the first member was molded using one sheet of continuous fiber reinforced resin X, the one side of which (the joining surface to which the second member was joined) of which had been heated to 300° C. in an IR heating furnace, and pressed with a clamping force of 10 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Example 3]
Continuous fiber reinforced resin X, only one side of which (the joining side surface to which the second member is joined) was heated to 300 ° C. in an IR heating furnace, was placed at a predetermined position in a molded body press mold at 120 ° C. with a cavity height of 2 mm corresponding to the shape of the first member, and pressed with a clamping force of 10 MPa to mold the first member (thickness 2.10 mm). The molding time was 3 minutes, and the continuous fiber reinforced resin X was cooled to 150 ° C. in the mold at 120 ° C. Next, while the first member was placed in the press mold for the molded body, the entire joining side surface of the one side (the joining side surface to which the second member is joined) of the first member to which the second member (discontinuous fiber reinforced resin Y) is joined was heated by an IR heater, and the resin on the surface was melted. Next, the press mold for the molded body was clamped at 10 MPa, and discontinuous fiber reinforced resin Y was injected and filled from the injection unit into the cavity of the press mold for the molded body corresponding to the shape of the second part at a cylinder setting temperature of 290°C, an injection pressure of 150 MPa, an injection speed of 100 mm/sec, and a holding pressure of 100 MPa to mold the second part.
The first member and the second member were joined by holding for 3 minutes. The press mold for the molded body was cooled to 100 ° C. to perform cooling and solidification, and the mold was opened and demolded to obtain a molded body having the shape shown in FIG. 1 (first member: length 250 mm × width 390 mm × thickness t 2.08 mm, second member: width W 3.5 mm × height H 17 mm). The taper angle of the recessed side of the press mold for the molded body was 3 °. The fiber orientation (warp and weft directions) of the first member was made to coincide with each longitudinal direction of the second member.
The physical properties of the obtained molded product are shown in Table 1.

[Example 4]
A molded body was obtained in the same manner as in Example 3, except that the mold clamping force during molding of the first member and the second member was both 15 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Example 5]
One sheet of continuous fiber reinforced resin X, both sides of which were heated to 300 ° C. in an IR heating furnace, was placed at a predetermined position in a press mold for the first member (cavity height corresponding to the shape of the first member was 2 mm), and pressed with a clamping force of 5 Pa to mold the first member (thickness 2.10 mm). The molding time was 3 minutes, and the mold was rapidly cooled to 150 ° C., and then opened to release the first member. Next, the entire joining side surface of one side (joining side surface to join the second member) of the first member to which the second member (discontinuous fiber reinforced resin Y) was joined was heated by an IR heater, and the resin on the surface was melted. Next, the heated first member was placed in a press mold for a molded body, and the cavity height of the press mold for a molded body, which corresponds to the shape of the first member, was set to 2 mm, and the mold was clamped at 15 MPa. Discontinuous fiber reinforced resin Y was injected and filled into the cavity of the press mold for a molded body from the injection unit at a cylinder setting temperature of 290°C, an injection pressure of 150 MPa, an injection speed of 100 mm/sec, and a holding pressure of 100 MPa, to mold the second member.
The first member and the second member were joined by holding for 3 minutes. The molded body was cooled to 120 ° C. in a press mold for cooling and solidifying, and the mold was opened and demolded to obtain a molded body having the shape shown in FIG. 1 (first member: length 250 mm × width 390 mm × thickness t 2.06 mm, second member: width W 3.5 mm × height H 17 mm). The taper angle of the recessed side of the press mold for molding was 3 °. The fiber orientation (warp and weft directions) of the first member was made to coincide with the longitudinal direction of the second member.
The physical properties of the obtained molded product are shown in Table 1.

[Example 6]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both 10 MPa, and the width W of the joint of the second member was 20.5 mm.
The physical properties of the obtained molded product are shown in Table 1.

[Example 7]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both 10 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Example 8]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both 10 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Example 9]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both 10 MPa, and the heating temperature in the double-sided IR heating furnace was 340°C.
The physical properties of the obtained molded product are shown in Table 1.

[Example 10]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both set to 2 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[ Reference Example 11]
Continuous fiber reinforced resin X, in which only one side (the joining side surface to which the second member is joined) is heated to 300 ° C. in an IR heating furnace, and discontinuous fiber reinforced resin Z, in which both sides are heated to 300 ° C. in an IR heating furnace, are placed at a predetermined position in a press mold for a molded body at 120 ° C. with a cavity height of 2 mm corresponding to the shape of the first member, and pressed with a clamping force of 10 MPa to mold the first member (thickness 2.10 mm) and the second member. The molding time was 3 minutes, and the continuous fiber reinforced resin X and the discontinuous fiber reinforced resin Z were cooled to 150 ° C. in a mold at 120 ° C. to perform cooling and solidification, and the mold was opened and released to obtain a molded body (first member: length 250 mm x width 390 mm x thickness t 2.02 mm, second member: width W 3.5 mm x height H 17 mm). The taper angle of the recess side of the press mold for the molded body was 3 °. The fiber orientation (warp and weft directions) of the first member was set to coincide with the longitudinal directions of the second member.
The physical properties of the obtained molded product are shown in Table 1.

[Example 12]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both 10 MPa, and the heating temperature in the double-sided IR heating furnace was 260°C.
The physical properties of the obtained molded product are shown in Table 1.

[Comparative Example 1]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both set to 30 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Comparative Example 2]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both set to 20 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Comparative Example 3]
A molded body was obtained in the same manner as in Example 1, except that the mold clamping force during molding of the first member and the second member was both set to 0.2 MPa.
The physical properties of the obtained molded product are shown in Table 1.

[Comparative Example 4]
A molded body was obtained in the same manner as in Example 7, except that the heating temperature in the double-sided IR heating furnace was 350° C. and the thickness of the continuous fiber reinforced resin X before molding the first member was 4.00 mm.
The physical properties of the obtained molded product are shown in Table 1.

[Comparative Example 5]
A molded article was obtained in the same manner as in Example 4, except that the continuous fiber reinforced resin X was heated on both sides.
The physical properties of the obtained molded product are shown in Table 1.

The molded article of the present invention has excellent strength and appearance, and is therefore particularly suitable for use in automobile parts such as oil pans, seat pans, pumps, cylinder head covers, gear boxes, and case parts, aircraft parts, railway parts, housing construction materials, robot parts, etc.

1: First member 2: Second member 3: Joint t1: Height of continuous reinforcing fiber in the first member at the joint

Claims (9)

A method for producing a molded body,
The molded body is
A first member including a continuous fiber reinforced resin including continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin including discontinuous reinforcing fibers,
At a joint between the first member and the second member, the first member bites into the second member, or the second member bites into the first member,
A ratio (t1/t) of a height t1 of the continuous reinforcing fiber at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00,
The manufacturing method includes:
A continuous fiber reinforced resin containing continuous reinforcing fibers is heated and then placed in a mold for molding, and the mold is clamped to mold a first member;
and heating, in the mold for molding, a joining side surface of the first member at a portion where the second member is to be joined or the entire joining side surface including the joining side surface, and then molding the second member using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.
When molding the second member, the height of a cavity in the mold for molding, which corresponds to the shape of the first member, is set to a range of ±25% of the thickness of the first member before molding (joining) the second member;
The molding of the second member is injection molding.
A method for producing a molded body, comprising: A method for producing a molded body,
The molded body is
A first member including a continuous fiber reinforced resin including continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin including discontinuous reinforcing fibers,
At a joint between the first member and the second member, the first member bites into the second member, or the second member bites into the first member,
A ratio (t1/t) of a height t1 of the continuous reinforcing fiber at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00,
The manufacturing method includes:
A continuous fiber reinforced resin containing continuous reinforcing fibers is heated and then placed in a mold for a first member, and the mold is clamped to mold the first member;
The first member is removed from the first member mold, and a joining side surface of a portion of the first member to which a second member is to be joined or an entire joining side surface including the joining side surface is heated;
The heated first member is placed in a mold for molding, and a second member is molded using a discontinuous fiber reinforced resin containing discontinuous reinforcing fibers,
When molding the second member, the height of a cavity in the mold for molding, which corresponds to the shape of the first member, is set to a range of ±25% of the thickness of the first member before molding (joining) the second member;
The molding of the second member is injection molding.
A method for producing a molded body, comprising: A method for producing a molded body,
The molded body is
A first member including a continuous fiber reinforced resin including continuous reinforcing fibers, and a second member joined to a surface of the first member and including a discontinuous fiber reinforced resin including discontinuous reinforcing fibers,
At a joint between the first member and the second member, the first member bites into the second member, or the second member bites into the first member,
A ratio (t1/t) of a height t1 of the continuous reinforcing fiber at the joint to a thickness t of the first member at a portion other than the joint is 0.50 to 2.00,
The manufacturing method includes:
The method includes heating a continuous fiber reinforced resin containing continuous reinforcing fibers, placing the heated continuous fiber reinforced resin in a mold for molding, clamping the mold with a clamping force such that a pressure in a clamping direction applied to the continuous fiber reinforced resin is 10 MPa or less to mold a first member, and then molding a second member using the heated discontinuous fiber reinforced resin containing discontinuous reinforcing fibers.
When molding the second member, the height of a cavity in the mold for molding, which corresponds to the shape of the first member, is set to a range of ±25% of the thickness of the first member before molding (joining) the second member;
The molding of the second member is injection molding.
A method for producing a molded body, comprising: The method for producing a molded body according to any one of claims 1 to 3, wherein a ratio ((t1-t)/W) of a difference t1-t obtained by subtracting the thickness t from the thickness t1 to a width W of the second member at the joint is -0.50 to 10.00. The method for producing a molded body according to any one of claims 1 to 4 , wherein the discontinuous reinforcing fibers have a fiber length of less than 3 mm. The method for producing a molded article according to any one of claims 1 to 4 , wherein the discontinuous reinforcing fibers have a fiber length of 3 mm or more. 7. The method for producing a molded body according to claim 1, wherein a ratio (σ _B 1'/σ _B 1) of the tensile strength of the first member in a direction along a surface of the first member, of the tensile strength σ _B 1' at the joint to the tensile strength σ _B 1 at a portion other than the joint, is 0.65 or more. 8. The method for producing a molded product according to claim 7, wherein a ratio (σ _J /σ _B 1') of an adhesive strength σ _J between the first member and the second member at the joint to the tensile strength σ _B 1' at the joint is 0.45 or less. The method for producing a molded product according to claim 1 , wherein the first member is pulled in at least two directions parallel to a surface of the first member when the second member is molded.

Images