JP2014051035A - Method of producing fiber-reinforced thermoplastic resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a molding which enables producing a molding having excellent dimensional stability with an increased yield.SOLUTION: A method of producing a molding comprises molding a random mat containing a reinforcing fiber of an average fiber length of 5-100 mm and a weight of 25-10000 g/m2 and a thermoplastic resin by a step 3 through steps 1 and 2, and in the carrying stage of the step 2, a substrate is deformed to the shape of a mold. The step 1 comprises heating the substrate to a temperature equal to or higher than the softening temperature of the thermoplastic resin; the step 2 comprises carrying the heated substrate into the mold; and the step 3 comprises adjusting the temperature of the mold to a temperature below the softening temperature of the thermoplastic temperature and molding the substrate.

Description

  The present invention relates to a method for producing a fiber-reinforced thermoplastic resin molded article having excellent dimensional stability and moldability. More specifically, the present invention relates to a method for producing a fiber-reinforced thermoplastic resin molded body having a high yield.

  In recent years, there has been an increasing demand for weight reduction in various fields such as electrical and electronic equipment, medical equipment, aircraft, building materials, and general industrial parts. The weight and rigidity of casings and members used in these fields are also increasing. It has come to be required. Fiber reinforced composite materials are excellent in specific strength, specific rigidity, and excellent in corrosion resistance, and thus are widely used in the aforementioned applications. For example, unidirectional materials in which reinforcing fibers are arranged in one direction and composite materials in which reinforcing fibers are arranged in a woven form are particularly excellent in specific strength and specific rigidity. Has been used in the center.

  Patent Document 1 proposes a composite molded product in which a resin member is bonded to the outer edge of a plate-like member made of a sheet containing reinforcing fibers, particularly continuous fibers. Thereby, it has become possible to realize a molded product having a complicated shape. However, since the technique is manufactured by laminating a plurality of reinforced fibers in the form of a woven fabric, the productivity is also low.

  On the other hand, Patent Document 2 describes a composite material related to a fiber-reinforced composite material using a thermoplastic resin as a matrix. This technique provides a fiber-reinforced composite material in which the molding time is significantly shortened by press-molding a prepreg containing reinforcing fibers that are two-dimensionally randomly oriented. In the future, in addition to shortening the molding time, it is desired to improve the yield in the manufacturing process.

JP 2010-131804 A JP 2011-178891 A

A unidirectional material in which reinforcing fibers are arranged in one direction and a composite material in which reinforcing fibers are arranged in a woven shape are difficult to be deformed during conveyance because the reinforcing fibers are oriented. Therefore, when molding a base material made of a unidirectional material or a composite material reinforced with a woven shape, it is necessary to place the base material in the mold cavity after cutting it out according to the mold shape. The base material portion cannot be effectively used, and the yield is lowered.
An object of this invention is to provide the manufacturing method of the molded object which can manufacture the molded object excellent in dimensional stability by making a yield high.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have reached the present invention.

1. A method for producing a molded article, comprising a random mat containing reinforcing fibers having an average fiber length of 1 to 100 mm and a basis weight of 25 to 10,000 g / m ² and a thermoplastic resin, comprising the following step 1 and step 2 in step 3 And the manufacturing method which deform | transforms a base material according to a metal mold | die shape in the conveyance process of the process 2. FIG.
Step 1. Step of heating the base material to a temperature higher than the softening temperature of the thermoplastic resin tree Step 2. Step of transporting heated substrate into mold Step 3. 1. Adjusting the mold temperature below the softening temperature of the thermoplastic resin and molding the substrate. 2. The method for producing a molded body according to 1 above, wherein the deformation in step 2 is deformation from a rectangular shape to a curved shape and / or a bent shape.
3. 3. The method for producing a molded article according to 2, wherein the degree of curvature of deformation in step 2 is a curvature radius of 30 mm or more.
4). The manufacturing method of the molded object in any one of said 1-3 whose area of the base material conveyed in the process 2 is 10,000 mm < ² > or more.
5. The manufacturing method of the molded object in any one of said 1-4 whose conveyance system in the process 2 is a piercing system with a needle.
6). 6. The method for producing a molded body according to 5 above, wherein the substrate removal method in step 2 is an extrusion method using a jig.
7). The manufacturing method of the molded object in any one of said 1-4 whose conveyance method of the base material in the process 2 is the pinching method by a grip.
8). The manufacturing method of the molded object in any one of said 1-4 whose conveyance system of the base material in the process 2 is a pulling-up system by suction.
9. Manufacture of the molded product according to any one of 1 to 8 above, wherein the proportion of the reinforcing fiber bundle (A) composed of the number of critical single yarns defined in (1) below is 20 Vol% or more and 99 Vol% or less. Method.
Critical number of single yarns = 600 / D (1)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)

  According to the production method of the present invention, the reinforcing fiber has an appropriate length and basis weight, and is arranged in a random direction. It is possible to prevent uneven distribution of the reinforcing fibers and tearing of the base material. Therefore, even if the shape of the molded body is complex, the base material can be deformed and conveyed according to the shape of the mold, making it possible to cut out the base material in a simple shape and improving the material yield. can do.

The front view which showed the whole apparatus in this invention. The top view which showed the cutting method of the random mat prepreg, and the bending method. A gripping tool for transporting random mat prepregs. Cutting pattern of random mat prepreg in the conventional method. An image diagram of a curved shape on both sides. (X-axis direction is width, Y-axis direction is length, Z-axis direction is thickness) Semicircular image. (X-axis direction is width, Y-axis direction is length, Z-axis direction is thickness) Image of curved and bent shapes. (X-axis direction is width, Y-axis direction is length, Z-axis direction is thickness) An image of a large curved shape at both ends. (X-axis direction is width, Y-axis direction is length, Z-axis direction is thickness) An image of a large, gently curved shape. (X-axis direction is width, Y-axis direction is length, Z-axis direction is thickness) The image figure at the time of calculating | requiring a curvature radius.

  Hereinafter, embodiments of the present invention will be described in order, but the present invention is not limited thereto.

[Reinforcing fiber]
The average fiber length of the reinforcing fibers used in the present invention is 1 to 100 mm. The average fiber length of the reinforcing fibers is preferably 5 to 100 mm, more preferably 10 to 100 mm, still more preferably 15 to 100 mm, and particularly preferably 15 to 80 mm. If the length of the reinforcing fiber is less than 5 mm, the base material is deformed in the transporting process of the base material, resulting in resin powder falling or uneven distribution of the reinforcing fiber in the resin. Moreover, when the length of the reinforcing fiber exceeds 100 mm, the handling property of the reinforcing fiber is deteriorated, which is not preferable. In the reinforcing fiber cutting method, when a random mat is manufactured by cutting reinforcing fibers into a fixed length, the average fiber length is substantially equal to the cut fiber length.

The basis weight of the reinforcing fiber used in the present invention is 25 to 10,000 g / m ² . When the basis weight is less than 25 g / m ² , the base material is fragile, and therefore, when the base material is transported, the base material is broken. On the other hand, if the basis weight of the reinforcing fiber is greater than 10,000 g / m ² , the substrate to be transported is too heavy, so that the substrate is detached from the transport device. Basis weight of reinforcing fibers, preferably 500~7000g / ^{m 2,} more preferably 1000~5000g / ^{m 2,} more preferably from 1500~3000g / ^{m 2.}

[Fiber volume content of reinforcing fiber (Vf)]
In the molded body and the random mat described later, the fiber volume content (Vf) is 5 to 80%, more preferably 20 to 60%. When the fiber volume content of the reinforcing fibers is higher than 5%, the reinforcing effect is improved. On the other hand, if it does not exceed 80%, voids are hardly generated in the molded body, and the physical properties of the molded body are improved.

[Opening degree]
In the random mat used in the present invention, in addition to a reinforcing fiber bundle composed of reinforcing fibers of a specific number or more in which the degree of opening of the reinforcing fibers is controlled, other opened reinforcing fibers are included at a specific ratio. It is preferable. That is, the reinforcing fiber in the present invention preferably contains a reinforcing fiber bundle composed of the number of critical single yarns defined by the formula (1) in a range of 20 Vol% or more and less than 99 Vol% of the reinforcing fiber. The range of 30 Vol% or more and 90 Vol% or less is more preferable.
Critical number of single yarns = 600 / D Formula (1)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)

  When the proportion of the reinforcing fiber bundle (A) with respect to the total amount of fibers is 20 Vol% or more, the fibers easily flow in the mold during molding. As a result, it becomes easy to fill the fiber up to the end of the mold cavity, and it becomes easy to obtain a molded body as designed. On the other hand, when the proportion of the reinforcing fiber bundle (A) is 99 Vol% or less, the entangled portion of the fibers is not locally thick, and a thin product is easily obtained. The ratio of the reinforcing fiber bundle (A) to the total amount of fibers is preferably 30 Vol% or more and less than 90 Vol%.

In addition, the ratio of a reinforcing fiber bundle (A) can be controlled by combining conditions, such as a widening process, a slit process, a cutting process, and a fiber opening process, in the manufacturing method mentioned later, for example.
Furthermore, it is preferable that the average number of fibers (N) in the reinforcing fiber bundle (A) satisfy the following formula (2).
0.7 × 10 ⁴ / D ² <N <1 × 10 ⁵ / D ² formula (2)
(In formula (2), D is the average fiber diameter (μm) of the reinforcing fibers)

  When the average fiber diameter of the carbon fibers constituting the random mat is 5 to 9 μm, the number of critical single yarns is 67 to 120. When the average fiber diameter of the carbon fibers is 5 μm, the reinforcing fiber bundle (A) The average number of fibers (N) is in the range of 280 to 4000, but when the average fiber diameter of the carbon fibers is 5 μm, the average number of fibers (N) in the reinforcing fiber bundle (A) is 280 to 2000. It is preferable that it is 600-1600 especially. When the average fiber diameter of the carbon fibers is 7 μm, the average number of fibers (N) in the reinforcing fiber bundle (A) is in the range of 142 to 2040, but when the average fiber diameter of the carbon fibers is 7 μm Is preferably 142 to 1020, and more preferably 300 to 800.

When the average number of fibers (N) in the reinforcing fiber bundle (A) is 0.7 × 10 ⁴ / D ² or more, it is easy to obtain a high fiber volume content (Vf). On the other hand, when the average number of fibers (N) in the reinforcing fiber bundle (A) is 1 × 10 ⁵ / D ² or less, locally thick portions are hardly formed and voids are hardly generated.

  In the random mat described later, the reinforcing fiber bundle (A) composed of the critical single yarn or more defined by the above-described formula (1) and the reinforcing fiber (B) in the single yarn state or less than the critical single yarn number are simultaneously present. By doing so, it becomes easy to obtain a random mat that is thin and has high physical properties.

[Types of reinforcing fibers]
There are no particular restrictions on the reinforcing fibers that make up the random mat, carbon fibers, glass fibers, stainless fibers, alumina fibers, mineral fibers and other inorganic fibers, polyether ether ketone fibers, polyphenylene sulfide fibers, polyether sulfone fibers, aramid fibers And organic fibers such as polybenzoxazole fiber, polyarylate fiber, polyketone fiber, polyester fiber, polyamide fiber, and polyvinyl alcohol fiber. Among these, in applications where the molded body is required to have strength and rigidity, it is preferably at least one selected from the group consisting of carbon fibers, aramid fibers, and glass fibers. For applications that require electrical conductivity, carbon fibers are preferred, and carbon fibers coated with a metal such as nickel are more preferred. In applications that require electromagnetic wave transparency, glass fibers and organic fibers are preferred, and aramid fibers and glass fibers are more preferred from the balance of electromagnetic wave permeability and strength. In applications where impact resistance is required, organic fibers are preferable, and polyamide fibers and polyester fibers are more preferable in consideration of cost. Among these, carbon fiber is preferable in that it can provide a molded body that is lightweight and excellent in strength.

[Average fiber diameter of reinforcing fibers]
The average fiber diameter of the reinforcing fibers is not particularly limited. For example, in the case of carbon fibers, the preferable average fiber diameter is 3 to 12 μm, more preferably 5 to 9 μm, and further preferably 5 to 7 μm. In the case of polyester fibers, the preferred average fiber diameter is 10 to 50 μm, more preferably 15 to 35 μm.
These can also be used in combination, and the type of reinforcing fiber can be used properly depending on the part of the molded body, and a molded body is produced in a state where random mats using different reinforcing fibers are laminated in whole or in part. Is also possible.

[Thermoplastic resin]
Examples of the thermoplastic resin used in the present invention include vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol resin, polystyrene resin, acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin). ), Acrylic resin, methacrylic resin, polyethylene resin, polypropylene resin, polyamide 6 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, polyamide 66 resin, polyamide 610 resin, polyacetal resin, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate Phthalate resin, boribylene terephthalate resin, polyarylate resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin Polyether sulfone resins, polyether ether ketone resins, such as polylactic acid resins.

The shape of the thermoplastic resin is not particularly limited, and for example, it can be supplied as a fiber, a particle, a molten state, or a mixture thereof.
In the case of a fiber, a fineness of 100 to 5000 dtex, more preferably 1000 to 2000 dtex is more preferred, and an average fiber length of 0.5 to 50 mm is preferred, and an average fiber length of 1 to 10 mm is more preferred.

In the case of particles, a spherical shape, a strip shape, or a columnar shape such as a pellet is preferable. In the case of a spherical shape, a perfect circle or ellipse shape, or an egg shape is preferable. A preferable average particle diameter in the case of a sphere is 0.01 to 1000 μm. More preferably, the average particle size is 0.1 to 900 μm, and still more preferably the average particle size is 1 to 800 μm. The particle size distribution is not particularly limited, but a sharp distribution is more preferable for the purpose of obtaining a thinner molded product, but can be used as a desired particle size distribution by an operation such as classification.
In the case of a strip shape, a columnar shape such as a pellet, a prismatic shape, or a flake shape is mentioned as a preferable shape. In this case, it may have a certain aspect ratio, but the preferred length is about the same as that of the above fibrous form.

  The abundance of the thermoplastic resin is preferably 50 to 1000 parts by weight, more preferably 50 to 500 parts by weight with respect to 100 parts by weight of the reinforcing fibers. More preferably, it is 60 to 300 parts by weight of the thermoplastic resin with respect to 100 parts by weight of the reinforcing fiber. When the ratio of the thermoplastic resin to 100 parts by weight of the reinforcing fiber is more than 50 parts by weight, voids are hardly generated in the prepreg, and the strength and rigidity tend to increase. On the contrary, when the proportion of the thermoplastic resin is less than 1000 parts by weight, the reinforcing effect of the reinforcing fibers is likely to appear. Two or more types of thermoplastic resins may be used as long as they are compatible.

[Other agents]
It should be noted that a functional filler or additive may be included in the random mat as long as the object of the present invention is not impaired. Examples include organic / inorganic fillers, flame retardants, UV-resistant agents, pigments, mold release agents, softeners, plasticizers, surfactants, and the like, but are not limited thereto. Particularly in electronic / electric equipment applications and automotive applications, high flame retardancy may be required, so it is preferable to contain a flame retardant. As an example of a flame retardant, a well-known thing can be used, and if it can give a flame retardance to the thermoplastic composition of this invention, it will not specifically limit. Specific examples include phosphorus flame retardants, nitrogen flame retardants, silicone compounds, organic alkali metal salts, organic alkaline earth metal salts, bromine flame retardants, etc. These flame retardants can be used alone. Alternatively, a plurality of them may be used in combination. The content of the flame retardant is preferably 1 to 40 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the resin from the balance of physical properties, moldability, and flame retardancy.

[Random mat]
In the random mat used in the production method of the present invention, the reinforcing fibers are oriented two-dimensionally randomly (two-dimensional isotropic). When a molded body is obtained from the random mat, the isotropy of the reinforcing fibers in the random mat is maintained in the molded body. Therefore, the two-dimensional isotropic quantitativeness is evaluated by obtaining a molded body from a random mat and determining the ratio of tensile modulus in two directions orthogonal to each other. The ratio (Eδ) obtained by dividing the measured value of the tensile modulus of elasticity by the smaller one for an arbitrary direction of the molded body and a direction orthogonal thereto is 2 or less, more preferably 1.3 or less. That means.
There is no restriction | limiting in particular in the thickness of a random mat, The thing of 1-150 mm thickness can be obtained, and it is more preferable to set it as 2-100 mm thickness.

[Random mat manufacturing method]
The production method of the random mat is not particularly limited. For example, the random mat may be produced so that a fibrous and / or particulate thermoplastic resin is mixed with the reinforcing fiber, and the reinforcing fiber is melted. It may be produced by supplying a thermoplastic resin.

  Below, the preferable manufacturing method of a random mat is illustrated. The method for producing a random mat preferably includes a method of performing the following steps (I), (III), (IV), (V) or (V ′), preferably (I) The method of performing the process of (II) between the processes of (III) is mentioned.

(I) Reinforcing fiber strand supply step In the reinforcing fiber strand supply step, each reinforcing fiber is drawn out from a plurality of reinforcing fiber wound bodies arranged in the creel portion, and consists of a single yarn or a single yarn. Supplied as reinforcing fiber strands that are drawn together. When the strand width of the reinforcing fiber to be supplied is small, the strand may be widened to a predetermined width in this strand supply step and supplied as a thin wide strand as necessary.

(II) Strand slit process In the strand slit process, the supplied reinforcing fiber strand is preferably slit continuously in parallel with the longitudinal direction of the strand (that is, along the fiber axis direction), and the strand width is 0.05 to 5 mm. Preferably, a plurality of narrow strands of 0.1 to 1.0 mm are used. Specifically, the wide strand continuously transferred from the previous step is continuously cut in the longitudinal direction using a slitting device (slitter) having a blade parallel to the fiber axis direction, or the wide strand One or a plurality of division guides are provided on the travel path, and the strands are divided into a plurality of pieces, for example.

(III) Reinforcing Fiber Cutting Step Next, in the reinforcing fiber cutting step, the fiber is cut (cut) into an average fiber length of 5 to 100 mm. In the reinforcing fiber cutting method, when the reinforcing fiber is manufactured by cutting it into a fixed length, the average fiber length is almost equal to the cut fiber length. As an apparatus used when cutting reinforcing fibers into an average fiber length of 5 to 100 mm, a rotary cutter is preferable.

(IV) Reinforcing Fiber Opening Step In the reinforcing fiber opening step, gas is blown onto a strand of reinforcing fibers cut to a predetermined fiber length (hereinafter sometimes referred to as “strand piece”), and the strand piece is formed in a desired shape. The fiber is opened so as to be divided into fiber bundles of size (number of bundles).
Specifically, in the reinforcing fiber opening step (IV), the strand pieces are introduced into the path, and a gas such as air is blown onto the strand pieces that pass through the path, so that the strand pieces have a desired converging size. Separate and disperse in gas. The degree of opening can be appropriately controlled by the pressure of the gas to be blown.
In this reinforcing fiber opening process, rather than separating all the fibers that make up the strand pieces apart and separating them until they become completely single yarns, some of them are opened to a single yarn shape or a state close thereto. However, it is preferable to adjust so that many portions become a bundle of fibers in which a certain number or more of single yarns are converged. That is, the degree of opening is such that the ratio of the reinforcing fiber bundle (A) consisting of the number of critical single yarns or more defined by the above formula (1) and the average number of fibers (N) in the reinforcing fiber bundle (A) are satisfied. Is preferable.

(V) Random mat forming step In the random mat forming step, the reinforcing fibers that have been cut and spread are diffused into the air, and at the same time, a granular or short fiber thermoplastic resin (hereinafter referred to as "therein mat"). (Collectively referred to as “thermoplastic resin particles, etc.”), and the reinforcing fibers and the thermoplastic resin particles, etc. are sprinkled on a breathable support provided below the opening device, and the reinforcing fibers and heat are spread on the support. A state in which plastic resin particles and the like are mixed is formed, and deposited and fixed to have a predetermined thickness, thereby forming a random mat.

(V ′) Random mat forming process (2)
As another random mat forming step, except that the matrix resin is not included, the reinforcing fibers are dispersed in the same manner as in the forming step (V), and then a molten thermoplastic resin is supplied to the reinforcing fibers. The method of obtaining the random mat containing a thermoplastic resin is mentioned. As such a method, for example, the opened reinforcing fiber strands obtained in the reinforcing fiber opening process are deposited in a mat shape, and a molten thermoplastic resin is formed from a die provided above as a film-like melt. The thermoplastic resin can be supplied onto the mat that has been discharged and deposited, so that the substantially entire surface of the mat can be impregnated.
The pressure in the impregnation is preferably from 0.1 to 30 MPa, more preferably from 0.5 to 20 MPa. The time is preferably from 0.1 to 60 minutes, more preferably from 0.5 to 30 minutes. If the pressure is low, it takes time to impregnate and tends to affect productivity. On the other hand, if the pressure is too high, a large molding machine and utility equipment will be required, resulting in high capital investment.

[Prepreg production process]
In the present invention, a material in which a thermoplastic resin is impregnated in a reinforcing fiber bundle and a reinforcing fiber in a random mat is called a prepreg. In order to further exhibit the performance of the random mat, it is preferable that the reinforcing fiber bundle is impregnated with a matrix resin, and the reinforcing fiber and the matrix resin are preferably integrated, and the impregnation treatment is performed somewhere in the manufacturing process of the molded body. And preferred. The impregnation treatment may be performed before step 1 or in step 1 in the method for manufacturing a molded body described later. The impregnation treatment can be performed at the same time as the molding in the step 3. However, if the impregnation and the molding are performed separately, the dimensional stability, physical properties, etc. of the molded product are adversely affected. Preferably it is done. In addition, the prepreg obtained by the impregnation treatment in step 1 may proceed to step 2 in a high temperature state, or may be cooled to room temperature once and subjected to desired processing, and then heated again to proceed to step 2. good.

In prepreg production, when the thermoplastic resin contained in the random mat is crystalline, it is heated to a temperature not lower than the melting point and lower than the thermal decomposition temperature, and if amorphous, it is heated to a temperature not lower than the glass transition temperature and lower than the thermal decomposition temperature, Impregnated with thermoplastic resin. There is no particular limitation on the heating method of the random mat and the prepreg, and any method can be used.
The thickness of the prepreg is preferably 1 to 10 times, preferably 1 to 5 times the thickness of the molded product to be obtained. Although there is no limitation on the thickness, it is preferably 0.1 mm or more, and the upper limit is a range that can be placed in a mold and molded, and is substantially about 30 mm.
The pressure in the impregnation is preferably from 0.1 to 30 MPa, more preferably from 0.5 to 20 MPa. The time is preferably from 0.1 to 60 minutes, more preferably from 0.5 to 30 minutes. If the pressure is low, the impregnation takes time. If the pressure is too high, a large molding machine and utility equipment are required.

  There is no particular limitation on the heating method of the random mat and the prepreg, and any method can be used. Specifically, a method using a hot air dryer or an electric heating dryer, a method using saturated steam or superheated steam, a method of sandwiching between hot plates in a mold, a belt conveyor, a heat roller, etc., infrared, far infrared, microwave -Dielectric heating by high frequency etc. and induction heating (IH) are illustrated. Among these, the method of sandwiching between hot plates, dielectric heating, and induction heating are more preferable because of high thermal efficiency.

[Method for measuring content of reinforcing fiber and thermoplastic resin]
The ratio of the reinforcing fiber and the thermoplastic resin in the random mat and the molded body can be evaluated using the difference in solubility. In this case, the weight of the plate-like sample having an area of 1 cm ² to 10 cm ² may be weighed, and the dissolved component may be extracted using a chemical that dissolves or decomposes one of the fibers and the resin. Thereafter, the residue is weighed after washing and drying, and the volume fraction of the fiber and the resin is calculated from the weight of the residue and the dissolved component and the specific gravity of the fiber and the resin. For example, when the thermoplastic resin is polypropylene, only the polypropylene can be dissolved by using heated toluene or xylene. When the thermoplastic resin is polyamide, the polyamide can be decomposed by heated formic acid. When the resin is polycarbonate, the polycarbonate can be dissolved by using heated chlorinated hydrocarbon. When the reinforcing fiber is an inorganic fiber such as carbon fiber or glass fiber, the weight and volume fraction can be calculated by burning and removing the resin. In this case, after weighing the well-dried sample, the resin component is burned by treatment at 500 to 700 ° C. for 5 to 60 minutes using an electric furnace or the like. The weight of each component can be calculated by weighing the fibers remaining in a dry atmosphere after cooling.

[Base material]
As the base material used in the present invention, a random mat may be used as it is, or a prepreg impregnated with a thermoplastic resin in the reinforcing fiber bundles and between the reinforcing fibers in the random mat may be used.

[Cut out substrate]
As shown in FIG. 2, the base material that is transferred and deformed in the present invention can be a base material that is cut out in a rectangular shape, but the cutting step is performed before Step 1 of the method for manufacturing a molded body described later. Alternatively, it may be between step 1 and step 2. The portion that remains when cut out becomes scrap.
Conventionally, when the mold used in step 3 has a curved shape, the base material is cut into a curved shape that matches the mold shape, and the curved base material is placed in the mold cavity. In this case, the base material portion (end material, shaded portion in FIG. 4) other than the curved shape portion cannot be effectively used.
On the other hand, in this invention, a base material deform | transforms at a conveyance process. For this reason, when the shape of the mold is a curved shape, the base material can be curved during conveyance after being cut out in a straight line, no scrap material is generated, and the base material is effectively used almost 100%. it can.

[Method for producing molded article]
The molded body of the present invention includes the following steps 1 and 2, and in the method for manufacturing a molded body molded in step 3, the substrate is deformed in accordance with the mold shape in the transporting step of step 2.
Step 1. Step of heating the base material to a temperature higher than the softening temperature of the thermoplastic resin tree Step 2. Step of transporting heated substrate into mold Step 3. The process of molding the substrate by adjusting the mold temperature below the softening temperature of the thermoplastic resin

[Step 1]
Step 1 is a preparation stage for molding. Since the thermoplastic resin that is the matrix of the substrate is hard in a state close to room temperature, when the resin is crystalline, it is heated to the melting point to the pyrolysis temperature, and when it is amorphous, it is heated to the glass transition temperature to the pyrolysis temperature. Gives flexibility to the substrate.

[Step 2]
In the molding method of the molded body in the present invention, the base material is deformed in accordance with the mold shape in the transporting step of Step 2. It is preferable that the substrate to be conveyed has a width of 300 mm to 2000 mm (X axis direction in FIG. 2), a length of 5 to 2000 mm (Y axis direction in FIG. 2), and a thickness of 0.5 mm to 10 mm (Z axis direction in FIG. 2).
Although there is no limitation in particular in the conveyance method in process 2, it is preferable that the temperature of a base material does not fall in order to shape | mold a complex-shaped molded object easily without loss. For this reason, it is preferable that the conveyance / supply speed is as high as possible, and it is more preferable if a heat retaining mechanism is provided.

Examples of such a transport device include equipment having a robot hand for picking up a base material. Equipment having a robot hand such as a fork is preferable because it can be transported in a short time, is easy to make compact, and various models are used in the fields of automobiles, industrial machinery, etc., and can be easily devised and applied. In addition, equipment having a robot hand such as a suction pad, a needle, and a grip is preferable because it can be transported in a short time.
The time required for conveyance is preferably 15 seconds or less, more preferably 10 seconds or less, and even more preferably 5 seconds or less. If the conveyance time is less than 15 seconds, the substrate is not cooled during that time, so that a desired shape can be formed. Further, it is more preferable that the transport device has a base material heat retaining function.

  In the case of a fragile base material, the heated base material is soft, so if the base material is deformed during transportation, the base material will lose its shape, the resin will fall off, the base material will tear, or the reinforcing fiber and resin will be separated or transported. Dropout occurs in whole or in part from the tool. On the other hand, if the random mat in the present invention is used, even if the base material is deformed according to the mold during transportation, the above-mentioned loss of shape, resin drop, base tearing, and uneven distribution of fibers contained in the base material Etc. can be suppressed. This is because the reinforcing fibers contained in the random mat have an appropriate length and are distributed in a random direction, so even if there is some shaking during transportation, the reinforcing fibers have the shape of the base material. Because it can be kept.

[Deformation in step 2]
There is no particular limitation on the shape to be deformed in the substrate transporting process, but a rectangular shaped substrate is curved and / or bent to be curved on both sides (FIG. 5), semicircular (FIG. 6), curved and bent. The combination shape (FIG. 7), large-end bending (FIG. 8), and large-scale bending shape (FIG. 9) can be obtained.
A unidirectional material in which reinforcing fibers are arranged in one direction and a prepreg in which the fibers are reinforced in a woven shape are difficult to deform the reinforcing fibers, so that it is difficult to deform the base material during conveyance. In the present invention, since the random at base material composed of reinforcing fibers having an average fiber length of 100 mm or less is curved and / or bent, the deformation resistance is small and the material can be deformed to a target shape.
On the other hand, even if a base material (thermoplastic resin alone) that does not contain reinforcing fibers is deformed during transportation, the base material during transportation is a thermoplastic resin that has exceeded its melting point, so that the molten resin is transferred to transportation equipment, etc. It is easy to adhere and it is difficult to carry it well to the target location.

Although there is no particular limitation on the size of the base material to be deformed, if the manufacturing method of the present invention is used, even if a relatively large base material is deformed in the transporting process, uneven distribution of reinforcing fibers in the base material, tearing of the base material The base material can be prevented from peeling off. Usually, when the size of the substrate to be transported increases, the weight of the substrate also increases, and a large load is applied to the substrate by handling the hand part of the transport robot. If a greater stress is applied to the substrate during transportation, the substrate is likely to fall off or collapse. With the manufacturing method of the present invention, the area of the substrate 10,000 mm ² or more, in the case of a larger substrate 40,000Mm ² or more, in the case of larger substrate was at 100,000 mm ² or more substrates However, it can be deformed according to the mold shape. The “base material area” here means a product of the width in the X-axis direction of FIG. 2 and the length in the Y-axis direction. Although there is no restriction | limiting in particular in the upper limit which can be conveyed, If it is 5,000,000 mm < ² > or less, it is preferable.

[Step 3]
The transported base material is a mold whose temperature is adjusted to below the softening temperature of the thermoplastic resin. Specifically, when the thermoplastic resin is crystalline, the thermoplastic resin is amorphous. In the case of property, it is set in a mold having a temperature lower than the glass transition temperature.
The base material is preferably arranged in the mold at a charge rate of 5 to 100% represented by the following formula (3). The charge rate is more preferably 20 to 95%, and the charge rate of the base material is further preferably 50 to 90%. When the charge rate exceeds 100%, a material that is lost during molding is generated. On the other hand, if the charge rate is less than 5%, the substrate is likely to be cooled during the flow of molding, and the desired shape may not be obtained.
Charge rate (%) = 100 × base material area (mm ² ) / mold cavity projected area (mm ² ) Formula (3)
(Here, the substrate area is the projected area of the arranged substrate in the drawing direction, and the mold cavity projected area is the projected area of the mold cavity in the drawing direction.)

In step 3, after forming the base material conveyed to the mold, or while forming, the temperature is lowered to finish the forming. The molding method may be a hot press or a cold press, but in view of productivity, a cold press with a short molding time is preferable. In the case of hot pressing, the mold temperature is from the melting point to the thermal decomposition temperature if the base thermoplastic resin is crystalline, and from the glass transition temperature to the thermal decomposition temperature if amorphous, and the mold temperature is changed to crystalline after molding. In the case of a resin, the temperature is lowered to below the melting point, and in the case of an amorphous resin, the temperature is lowered to below the glass transition temperature, the molded product is cooled and released, and the molding is terminated. In the case of a cold press, the mold temperature is less than the melting point if the thermoplastic resin of the substrate is crystalline, and less than the glass transition temperature if the thermoplastic resin is amorphous.
The molding pressure is preferably 0.1 to 50 MPa, more preferably 0.5 to 30 MPa. The molding time is preferably from 0.1 to 60 minutes, more preferably from 0.5 to 30 minutes. If the pressure is low, it takes time to form and tends to affect productivity. If the pressure is too high, a large molding machine and utility equipment are required.

  In this invention, it is good to arrange | position with a low charge with respect to a metal mold | die shape, and to make a base material flow by pressurizing. Thereby, it becomes easy to fill the base material into a complicated shape. Usually, when a thermoplastic resin material containing reinforcing fibers is flowed, the reinforcing fibers tend to be oriented in the flow direction, and anisotropy may occur in physical properties. In the present invention, the random mat described above is used. Thus, a complicated shape can be obtained while maintaining the isotropy of the reinforcing fiber.

[curvature radius]
When the deformation in the step 2 is a curve, the degree of the curve can be indicated by a radius of curvature (the length of 9 in FIG. 10). In the deformation in step 2, if the radius of curvature is reduced, wrinkles will occur on the base material, but the wrinkles disappear easily because the thermoplastic resin flows during molding in step 3. If the curvature radius is 30 mm or more, it is preferable that the substrate is difficult to tear. A curvature radius becomes like this. Preferably it is 50 mm or more, More preferably, it is 100 mm or more, More preferably, it is 200 mm or more.

[Molded body]
The produced molded body is preferably impregnated with a thermoplastic resin in a fiber bundle of reinforcing fibers and between single yarns, and the degree of impregnation is more preferably 90% or more. More preferably, the degree of impregnation of the resin into the reinforcing fibers is 95% or more. When the degree of impregnation is high, the physical properties of the molded body can reach a higher level. In the molded body impregnated with the resin, the fiber length of the reinforcing fiber and the ratio of the bundle to the single yarn are kept in the random mat. The molded body of the present invention can have various thicknesses, but a thin product having a thickness of about 0.2 to 1 mm can also be suitably obtained.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these.

[Evaluation method]
(1) Analysis of reinforcing fiber bundle in random mat A random mat that is not impregnated with resin is cut out to about 100 mm × 100 mm. From the cut out random mat, the fiber bundles were all taken out with tweezers, and the number (I) of fiber bundles and the length (Li) and weight (Wi) of the fiber bundles were measured and recorded. When the fiber bundle is so small that it cannot be taken out by tweezers, the weight is finally measured together (Wk). For the weight measurement, a balance capable of measuring up to 1/100 mg was used. In particular, when the reinforcing fiber is a carbon fiber, or when the fiber length is short, the weight of the fiber bundle is small and measurement is difficult. In such a case, a plurality of classified fiber bundles were collectively measured for weight.
The number of critical single yarns is calculated from the fiber diameter (D) of the reinforcing fibers, and the bundle is divided into reinforcing fiber bundles (A) having the number of critical single yarns or more and others. In addition, when two or more types of reinforcing fibers are used, it is divided for each type of fiber, and measurement and evaluation are performed for each.

(2) Reinforcing fiber bundle analysis in molded body The molded body was measured in the same manner as in the above random mat after the resin was burned and removed in a furnace at 500 ° C for 1 hour.

(3) Analysis of the average fiber length of the reinforcing fibers contained in the random mat The length of 100 reinforcing fibers randomly extracted from the random mat was measured and recorded to the 1 mm unit with calipers and loupes, and all the measured reinforcements were measured. From the fiber length (Li), the average fiber length (La) was determined by the following formula. In the case of the composite material, after removing the resin in the furnace at about 500 ° C. for about 1 hour, the reinforcing fibers were extracted.
La = ΣLi / 100

(4) Analysis of average fiber length and volume fraction of reinforced fibers contained in prepreg or molded body The average fiber length of reinforced fibers contained in prepreg or molded body is about 500 ° C x 1 hour, and the resin is removed in a furnace. Then, the measurement was performed in the same manner as in the above random mat.
For the volume fraction, the weight of the fiber and the resin was calculated by burning and removing the resin and weighing the sample before and after the treatment. Next, the volume fraction of the fiber and the resin was calculated using the specific gravity of each component.

(5) Dimensional stability evaluation After the produced molded body was allowed to stand at 23 ° C. and 55% humidity for 48 hours or longer, the dimensions (length, width, thickness) of the molded body were measured and compared with the design dimensions. The displacement rate was calculated from the difference. The number of N of the molded body was 10, and the case where the largest dimensional displacement rate was 5% or less was judged as acceptable (◯), and the case where it exceeded 5% was regarded as unacceptable (x).

(6) The yield was calculated by the following calculation method.
(Area of the base material−Area of the end material) ÷ Area of the base material The end material refers to a portion remaining when the base material to be conveyed is cut out.

(7) Method of measuring radius of curvature A rectangular substrate is heated, curved while maintaining a flat surface on a flat plate, and then cooled and solidified. The radius of curvature at the center line of the substrate after cooling was measured with a scale to obtain a radius of curvature (9 in FIG. 10).

[Reference Example 1]
While opening carbon fiber (manufactured by Toho Tenax Co., Ltd .: Tenax STS40-24KS (fiber diameter 7 μm, fiber width 10 mm)) to a width of 20 mm, the fiber length is cut to 10 mm, and the amount of carbon fiber supplied is 301 g / min. The air was blown onto the carbon fiber in the taper tube, and the fiber bundle was partially opened to spread on the table installed at the lower part of the taper tube outlet. Also, as a matrix resin, PA66 fiber (Asahi Kasei Fibers polyamide 66 fiber: T5 nylon, fineness 1400 dtex) dry-cut to 2 mm is supplied into the tapered tube at 430 g / min and dispersed simultaneously with the carbon fiber, resulting in an average fiber length of 10 mm. A random mat having a carbon fiber weight per unit area of 317 g / m ² was obtained in which the carbon fiber and PA66 were mixed.
When the form of the reinforcing fiber in the random mat was observed, the fiber axis of the reinforcing fiber was almost parallel to the surface and was randomly distributed in the surface. The ratio of PA66 with respect to 100 parts by weight of carbon fiber was 143 parts by weight. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length (La) was defined as 10 mm and the formula (1). The number of critical single yarns was 86, and with respect to the reinforcing fiber bundle (A), the ratio of the random mat to the total amount of fibers was 35%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 240.

[Reference Example 2]
The same operation as in Reference Example 1 was carried out except that the amount of carbon fiber shared into the tapered tube was 451 g / min for the supply rate and 643 g / min for the PA66 fiber, and the carbon fiber having an average fiber length of 10 mm and A random mat having a carbon fiber basis weight of 2520 g / m ² mixed with PA66 was obtained. When the form of the reinforcing fiber in the random mat was observed, the fiber axis of the reinforcing fiber was almost parallel to the surface and was randomly distributed in the surface. The ratio of PA66 with respect to 100 parts by weight of carbon fiber was 143 parts by weight. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length (La) was defined as 10 mm and the formula (1). The number of critical single yarns was 86, and with respect to the reinforcing fiber bundle (A), the ratio of the mat to the total amount of fibers was 35%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 240.

[Reference Example 3]
The same operation as in Reference Example 1 was performed except that the cut length of the carbon fiber was changed to 0.9 mm, and a carbon fiber having an average fiber length of 0.9 mm and PA66 were mixed, and the carbon fiber basis weight was 317 g / m ² . A mat was obtained. When the form of the reinforcing fiber in the random mat was observed, the fiber axis of the reinforcing fiber was almost parallel to the surface and was randomly distributed in the surface. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) of the obtained random mat and the average number of fibers (N) were examined, the average fiber length (La) was 0.9 mm and the formula (1) The number of critical single yarns defined was 86. For the reinforcing fiber bundle (A), the ratio of the random mat to the total amount of fibers was 35%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 240.

[Reference Example 4]
The same operation as in Reference Example 1 was performed except that the supply amount of carbon fiber into the tapered tube was 22 g / min and the supply amount of PA66 fiber was 31 g / min, and carbon fiber having an average fiber length of 10 mm and PA66 were mixed. A random mat having a carbon fiber basis weight of 23 g / m ² was obtained. When the form of the reinforcing fiber in the random mat was observed, the fiber axis of the reinforcing fiber was almost parallel to the surface and was randomly distributed in the surface. The ratio of PA66 with respect to 100 parts by weight of carbon fiber was 143 parts by weight. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length (La) was defined as 10 mm and the formula (1). The number of critical single yarns was 86, and with respect to the reinforcing fiber bundle (A), the ratio of the mat to the total amount of fibers was 35%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 240. This random mat is fragile because the basis weight of the carbon fiber is too small, and tends to be broken when handled a little roughly.

[Reference Example 5]
The same operation as in Reference Example 1 was performed except that the amount of carbon fiber shared into the taper tube was 2408 g / min and the amount of PA66 fiber supplied was 3440 g / min, and carbon fibers having an average fiber length of 10 mm A random mat having a carbon fiber basis weight of 13440 g / m ² mixed with PA66 was obtained. When the form of the reinforcing fiber in the random mat was observed, the fiber axis of the reinforcing fiber was almost parallel to the surface and was randomly distributed in the surface. The ratio of PA66 with respect to 100 parts by weight of carbon fiber was 143 parts by weight. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length (La) was defined as 10 mm and the formula (1). The number of critical single yarns was 86, and with respect to the reinforcing fiber bundle (A), the ratio of the mat to the total amount of fibers was 35%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 240.

[Reference Example 6]
Carbon fibers (manufactured by Toho Tenax Co., Ltd .: Tenax STS40-24KS (fiber diameter 7 μm, fiber width 10 mm)) are arranged in a sheet shape of 20 mm width, impregnated with a thermoplastic resin without being cut, and fiber orientation. Prepared a unidirectional substrate.

[Example 1]
The random mat produced in Reference Example 1 was heated, and after reaching 260 ° C. and pressurized at a pressure of 5 MPa for 7 minutes, it was cooled to 50 ° C. to obtain a prepreg with a carbon fiber basis weight of 317 g / m ² . PA66 was 143 weight part with respect to 100 weight part of carbon fibers. The obtained prepreg was cut out as shown in FIG. 2 to prepare a prepreg having a width of 1000 mm × a length of 50 mm × a thickness of 3.2 mm.
Next, using a transfer robot having a needle piercing mechanism shown in FIG. 1, one piece of the above-mentioned cut prepreg in a heated state is pierced and lifted, and then conveyed while curving into the shape shown in FIG. A mold adjusted to 120 ° C. was set to fit the shape of the molded product. The area of the cut prepreg was about 80% of the projected area of the mold cavity (charge rate 80%). The outer dimension of the cavity portion of this mold was 600 mm × 600 mm, and was a shape close to a circumferential curve. Thereafter, cold press molding was performed at a pressure of 10 MPa for 40 seconds using a hydraulic press machine manufactured by Kawasaki Oil Works.
The time taken for the transfer robot to transfer the heated random mat to the mold was about 3 seconds. The weight of the prepreg before conveyance was 210.0 g and after conveyance was 210.0 g. The base material was able to effectively utilize all surfaces except for the end part of 20 mm in total, and the yield of the base material was 98%.
The obtained molded body has a width of 600 mm, a length of 600 mm, and a thickness of 2.5 mm, is curved with a radius of 400 mm on one side and a radius of 100 mm on the other side, and has a curved shape on both sides as shown in FIG. The volume fraction of was 30%. The curvature radius at this time was 100 mm. The results are shown in Table 2.

[Example 2]
The random mat produced in Reference Example 1 was heated, and after reaching 260 ° C. and pressurized at a pressure of 5 MPa for 7 minutes, it was cooled to 50 ° C. to obtain a prepreg with a carbon fiber basis weight of 317 g / m ² . PA66 was 143 weight part with respect to 100 weight part of carbon fibers. The obtained prepreg was cut out to prepare a prepreg having a width of 1000 mm, a cut length of 50 mm, and a thickness of 3.2 mm.
Next, using a transfer robot having a grip mechanism, one of the heated cut prepregs is lifted, and then transferred while curving into the shape shown in FIG. 5, and the temperature is adjusted to 120 ° C. It was set to fit the shape of the molded product. The area of the cut prepreg was about 80% of the projected area of the mold cavity (charge rate 80%). The outer dimension of the cavity portion of this mold was 600 mm × 600 mm, and was a shape close to a circumferential curve. Thereafter, cold press molding was performed at a pressure of 20 MPa for 40 seconds using a hydraulic press machine manufactured by Kawasaki Oil Works.
The time taken for the transfer robot to transfer the heated random mat to the mold was about 3 seconds. The weight of the prepreg before conveyance was 210.0 g and after conveyance was 210.0 g. The base material was able to effectively utilize all surfaces except for the 20 mm ends at both ends, and the yield of the base material was 98%.
The obtained molded body is of a curved shape shown in FIG. 5, which is curved with a width of 600 mm × a length of 600 mm × a thickness of 2.5 mm, with a radius on one side of 400 mm and a radius on the other side of 50 mm. The volume fraction was 30%. The curvature radius at this time was 100 mm. The results are shown in Table 2.

[Example 3]
Except that the size of the cut prepreg is 1100 mm wide × 10 mm long × 3.2 mm thick and the shape of the mold cavity is the same as that shown in Example 2, one prepreg in a heated state is shown in FIG. The base material was curved on the transport device into the shape indicated by 6. The time taken for the transfer robot to transfer the heated random mat to the mold was about 5 seconds. The weight of the prepreg before conveyance was 47.0 g, and after the conveyance was 47.0 g. The base material was able to effectively utilize all surfaces except for the 20 mm ends at both ends, and the yield of the base material was 98%.
Thereafter, the grip was released, the base material was placed in the mold cavity, and cold pressing was performed for 40 seconds at a pressure of 20 MPa using a Kawasaki Oil Works press. The obtained molded body was 700 mm wide × 300 mm long × 2.5 mm thick. Moreover, the curvature radius at this time was 50 mm, and it was able to be molded well even with a small curvature radius. The results are shown in Table 2.

[Example 4]
Except that the size of the cut prepreg is 2200 mm wide × 50 mm long × 3.2 mm thick, and the shape of the mold cavity is the same as that shown in Example 2, one prepreg in a heated state is shown in FIG. The base material was gently curved on the transport device into the shape indicated by 8. Since the curve was gradual, the wrinkles generated on the conveying device were small. The time taken for the transfer robot to transfer the heated random mat to the mold was about 5 seconds. The weight of the prepreg before conveyance was 466.0 g, and after conveyance, it was 466.0 g. The base material was able to effectively utilize all surfaces except for the 20 mm ends at both ends, and the yield of the base material was 99%.
Thereafter, the grip was released, the base material was placed in the mold cavity, and cold pressing was performed for 40 seconds at a pressure of 20 MPa using a Kawasaki Oil Works press. The obtained molded body was 1700 mm wide × 400 mm long × 2.5 mm thick. Moreover, the curvature radius at this time was 200 mm. The results are shown in Table 2.

[Example 5]
The treatment was performed under the same conditions as in Example 3 except that the base material of Reference Example 2 was used. The time for transferring the heated prepreg to the mold by the transfer robot was about 5 seconds. The weight of the prepreg before conveyance was 70.0 g, and after the conveyance was 70.0 g. The base material was able to effectively utilize all surfaces except for the 20 mm ends at both ends, and the yield of the base material was 99%. Thereafter, the grip was released, the base material was placed in the mold cavity, and cold pressing was performed for 40 seconds at a pressure of 20 MPa using a press machine. The obtained molded body was 1700 mm wide × 400 mm long × 2.5 mm thick. Further, the radius of curvature at this time was 30 mm. The results are shown in Table 2. Although the basis weight was large and the deformation during transportation was large, the shape could be maintained by the fibers in the random mat, and a good molded product was obtained.

[Comparative Example 1]
The sample was cut in a curved shape according to the shape of the molded product (FIG. 4), and moved to the mold under the conditions shown in Example 2 except that the substrate was moved without being deformed during conveyance. Many portions of the base material other than the shape of the molded body were end materials, and the material yield was only 70%.

[Comparative Example 2]
A molded body was obtained by processing under the same conditions as in Example 2 except that the random mat produced in Reference Example 3 was used as the substrate. The time for transferring the heated prepreg to the mold by the transfer robot was about 5 seconds. Since the heated prepreg was too soft, the base material was dropped due to deformation of the base material in the transport step of Step 2, and the post-transport weight was 170 g against the prepreg weight of 210.0 g before transport. The obtained molded body was 600 mm wide × 600 mm long × 2.0 mm thick, and was inferior in dimensional stability to a planned thickness of 2.5 mm. The results are shown in Table 2.

[Comparative Example 3]
An attempt was made to treat the random mat produced in Reference Example 4 under the same conditions as in Example 1. However, the heated prepreg was often dropped during the conveyance, and molding was not achieved. The results are shown in Table 2.

[Comparative Example 4]
Except for using a prepreg with a carbon fiber basis weight of 13440 g / m ² created in Reference Example 5, the treatment was performed under the same conditions as in Example 3. However, because the prepreg was too heavy, the prepreg was lifted and curved. The grip of the conveying device was released when the prepreg was removed.

[Comparative Example 5]
An attempt was made to treat the base material with the fiber orientation unidirectionally produced in Reference Example 6 under the same conditions as in Example 3. However, since the fibers of the base material are concentrated outside the curve, the thickness on the outside increases. On the contrary, the inner space became larger. As a result, the target shape (the shape shown in FIG. 6) could not be bent, and the molding was stopped.

1 Base material (Random mat or prepreg)
2 Press machine or mold clamping machine 3 Gripping part 4 Heating heater 5 Substrate outlet opening 6 Transfer robot 7 Puncture-type gripping tool 8 Suction-type gripping tool 9 Curvature radius

Claims (9)

A method for producing a molded article, comprising a random mat containing reinforcing fibers having an average fiber length of 1 to 100 mm and a basis weight of 25 to 10000 g / m ² and a thermoplastic resin, comprising the following step 1 and step 2 in step 3 And the manufacturing method which deform | transforms a base material according to a metal mold | die shape in the conveyance process of the process 2. FIG.
Step 1. Step of heating the base material to a temperature higher than the softening temperature of the thermoplastic resin tree Step 2. Step of transporting heated substrate into mold Step 3. The process of molding the substrate by adjusting the mold temperature below the softening temperature of the thermoplastic resin   The method for producing a molded body according to claim 1, wherein the deformation in step 2 is a deformation from a rectangular shape to a curved shape and / or a bent shape.   The method of manufacturing a molded body according to claim 2, wherein the degree of curvature of deformation in step 2 is a curvature radius of 30 mm or more. The method for producing a molded body according to any one of claims 1 to 3, wherein an area of the substrate conveyed in step 2 is 10,000 mm ² or more.   The method for producing a molded body according to any one of claims 1 to 4, wherein the conveying method in step 2 is a piercing method using a needle.   The method for producing a molded body according to claim 5, wherein the removal method of the base material in step 2 is an extrusion method using a jig.   The manufacturing method of the molded object in any one of Claims 1-4 whose conveyance system of the base material in the process 2 is the pinching system by a grip.   The manufacturing method of the molded object in any one of Claims 1-4 whose conveyance system of the base material in the process 2 is a pulling-up system by suction. The ratio of the reinforcing fiber bundle (A) constituted by the number of critical single yarns or more defined in (1) below is 20 Vol% or more and 99 Vol% or less of the molded body according to any one of claims 1 to 8. Production method.
Critical number of single yarns = 600 / D (1)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)

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