JP2019156920A - Method for producing fiber-reinforced thermoplastic resin material, method for producing mixed nonwoven fabric, fiber-reinforced thermoplastic resin material and structure - Google Patents

Abstract

To provide a method for producing a fiber-reinforced thermoplastic resin material with an excellent elastic modulus.SOLUTION: A method for producing a fiber-reinforced thermoplastic resin material has: a preparation step for preparing a mixed nonwoven fabric containing a reinforced fiber and a thermoplastic resin component; a lamination step for laminating the mixed nonwoven fabric to obtain a laminate; and a heating pressurizing step for heating and pressurizing the laminate.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a fiber reinforced thermoplastic resin material, a method for producing a mixed nonwoven fabric, a fiber reinforced thermoplastic resin material, and a structure.

A fiber reinforced thermoplastic resin material containing a reinforced fiber and a thermoplastic resin has been attracting attention as a material for a structure constituting an automobile-related part, a home appliance part, and the like because it is lightweight and has high strength.
The fiber-reinforced thermoplastic resin material can be obtained, for example, by heat-treating a laminate obtained by alternately stacking fiber sheets containing reinforcing fibers and a thermoplastic resin nonwoven fabric with a hot press (for example, , See Patent Document 1).

JP 2015-44915 A

  In order to further expand the application of the fiber reinforced thermoplastic resin material, an improvement in the elastic modulus of the fiber reinforced thermoplastic resin material is required. However, the fiber-reinforced thermoplastic resin material obtained by the method described in Patent Document 1 has room for improvement for improving the elastic modulus.

  One aspect of the present invention has been made in view of the above-described conventional circumstances, and a fiber-reinforced thermoplastic resin material having excellent elastic modulus, a structure using the same, and production of a fiber-reinforced thermoplastic resin material having excellent elastic modulus. It is an object of the present invention to provide a method and a method for producing a mixed non-woven fabric used for producing a fiber-reinforced thermoplastic resin material.

Specific means for achieving the above object are as follows.
<1> a preparation step of preparing a non-woven fabric containing a reinforcing fiber and a thermoplastic resin component;
Laminating step of laminating the mixed nonwoven fabric to obtain a laminate,
A heating and pressurizing step of heating and pressurizing the laminate;
The manufacturing method of the fiber reinforced thermoplastic resin material which has this.
<2> The method for producing a fiber-reinforced thermoplastic resin material according to <1>, wherein the mixed nonwoven fabric is obtained by making a fiber slurry containing the reinforcing fiber, the thermoplastic resin component, and a dispersion medium. .
<3> The method for producing a fiber-reinforced thermoplastic resin material according to <1> or <2>, wherein the thermoplastic resin component is fibrous.
<4> A method for producing a mixed non-woven fabric having a paper making step of making a fiber slurry containing reinforcing fibers, a thermoplastic resin component, and a dispersion medium.
<5> When the fracture surface is observed, the adhesion rate obtained from the following formula from the number A of reinforcing fibers to which the thermoplastic resin component is attached and the number B of reinforcing fibers to which the thermoplastic resin component is not attached is 30% or more of fiber reinforced thermoplastic resin material.
Adhesion rate (%) = [A / (A + B)] × 100
<6> A fiber reinforced thermoplastic resin material produced by the method for producing a fiber reinforced thermoplastic resin material described in any one of <1> to <3> or a fiber reinforced thermoplastic resin material described in <5>. A structure partially or entirely composed of

  According to one aspect of the present invention, a fiber-reinforced thermoplastic resin material excellent in elastic modulus and a structure using the same, a method for producing a fiber-reinforced thermoplastic resin material excellent in elastic modulus, and a fiber-reinforced thermoplastic resin material The manufacturing method of the mixed paper nonwoven fabric used for manufacture can be provided.

2 is an electron micrograph of a fracture surface of a fiber-reinforced thermoplastic resin material of Example 1. FIG. 2 is an electron micrograph of a fracture surface of a fiber-reinforced thermoplastic resin material of Example 2. FIG. 2 is an electron micrograph of a fracture surface of a fiber-reinforced thermoplastic resin material of Comparative Example 1.

Hereinafter, the manufacturing method of the fiber reinforced thermoplastic resin material of the present invention, the manufacturing method of the mixed nonwoven fabric, the fiber reinforced thermoplastic resin material, and the form for carrying out the structure will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and the present invention is not limited thereto.
In the present disclosure, the numerical ranges indicated using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical description. . Further, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present disclosure, each component may contain a plurality of corresponding substances. When a plurality of substances corresponding to each component are present in the composition, the content of each component means the total content of the plurality of substances present in the composition unless otherwise specified.

<Method for producing fiber-reinforced thermoplastic resin material>
The manufacturing method of the fiber reinforced thermoplastic resin material of the present disclosure includes a preparation step of preparing a mixed non-woven fabric containing reinforcing fibers and a thermoplastic resin component, a stacking step of stacking the mixed non-woven fabric to obtain a laminate, and the stacking Heating and pressurizing step for heating and pressurizing the body.
Since the mixed non-woven fabric used in the method for producing the fiber-reinforced thermoplastic resin material of the present disclosure includes the reinforcing fiber and the thermoplastic resin component, the fiber sheet including the reinforcing fiber and the thermoplastic resin non-woven fabric are alternately overlapped. Compared with the case where a laminate is used, each of the reinforcing fibers can be brought close to the thermoplastic resin component. By heating and pressing a laminate obtained by laminating a mixed nonwoven fabric in which each of the reinforcing fiber fibers and the thermoplastic resin component are close to each other, a fiber sheet containing the reinforcing fibers and the thermoplastic resin nonwoven fabric Compared to heating and pressurizing a laminate obtained by alternately stacking layers, the impregnation into the reinforcing fiber of the thermoplastic resin component in the heating and pressurizing process is ensured, and the molten thermoplastic resin component is It is considered that the reinforcing fiber is more easily entangled with the reinforcing fiber. As a result, the adhesive force between the thermoplastic resin component and the reinforcing fiber is strengthened, and peeling between the thermoplastic resin component and the reinforcing fiber is less likely to occur, so the elastic modulus of the fiber-reinforced thermoplastic resin material is improved. It is guessed.

  Hereinafter, each process included in the manufacturing method of the fiber-reinforced thermoplastic resin material of the present disclosure and details of the material used will be described.

-Preparation process-
In the preparation step, a mixed nonwoven fabric containing reinforcing fibers and a thermoplastic resin component is prepared.
The reinforcing fiber is not particularly limited, and may be an inorganic fiber or an organic fiber (resin fiber). In addition, as a resin fiber, it is preferable that it is a resin fiber which shows the glass transition temperature higher than the temperature applied in a heating-pressing process from a viewpoint of maintaining the shape of a resin fiber in a fiber reinforced thermoplastic resin material.

Examples of the inorganic fiber include carbon fiber, glass fiber, and metal fiber.
Examples of the resin fiber include aramid fiber, polyimide fiber, polybenzoxazole fiber, and the like.
Reinforcing fibers may be used alone or in combination of two or more.
Among these, carbon fibers that can realize high mechanical strength are desirable.

The fiber length of the reinforcing fiber is not particularly limited, and is preferably 2 mm or more, more preferably 5 mm or more, and further preferably 8 mm or more from the viewpoint of strength. Further, the fiber length of the reinforcing fiber is preferably 100 mm or less, more preferably 80 mm or less, and further preferably 50 mm or less from the viewpoint of handleability.
In the present disclosure, the fiber length is a value obtained by measuring the length of each of 100 fibers randomly selected to the nearest 0.1 mm and calculating the arithmetic average.

The fiber diameter of the reinforcing fiber is not limited, and is preferably 5 μm or more, more preferably 7 μm or more, and even more preferably 10 μm or more from the viewpoint of strength. Further, the fiber diameter of the reinforcing fiber is preferably 100 μm or less, more preferably 80 μm or less, and further preferably 50 μm or less from the viewpoint of handleability.
In the present disclosure, the fiber diameter is a value obtained as an arithmetic average by measuring the diameter of each of 100 fibers randomly selected up to 0.1 μm with an electron microscope.

  The reinforcing fiber may be surface-treated with a coupling agent. The coupling agent that can be used for the surface treatment of the reinforcing fiber is not particularly limited, and can be appropriately selected from conventionally known ones. Examples of the coupling agent include silane compounds such as epoxy silane, mercapto silane, alkyl silane, and vinyl silane; titanate compounds.

  Specific examples of the coupling agent include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy. Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, γ Silane coupling agents such as chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane; isopropyl triisostearoyl tita , Isopropyltris (dioctylpyrophosphate) titanate, tetraoctylbis (ditridecylphosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecylphosphite) titanate, bis (dioctylpyrophosphate) ) Oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropylisostearoyl diacryl titanate, isopropyltri (dioctylphosphate) titanate, isopropyl Tricumylphenyl titanate, tetraisopropylbis (dioctyl Phosphite), and the like titanate coupling agents such as titanates. These coupling agents may be used alone or in combination of two or more.

  The surface treatment method of the reinforcing fiber with the coupling agent is not particularly limited, and examples thereof include a spray method and a dip method.

The thermoplastic resin component is not particularly limited. The thermoplastic resin component is preferably a resin exhibiting a glass transition temperature lower than the temperature applied in the heating and pressing step.
Examples of the thermoplastic resin component include polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polyurethane, polypropylene, polyethylene, polycarbonate, polyether ether ketone, polyamide imide, polyphenylene sulfide, polyether imide, polyether ketone ketone, and the like. it can.
A thermoplastic resin component may be used individually by 1 type, or may use 2 or more types together.
Among these, polyamide or polypropylene is desirable from the viewpoint of heat resistance and solubility.

  The glass transition temperature of the thermoplastic resin component can be appropriately set in view of the temperature applied in the heating and pressurizing step, is preferably 350 ° C. or less, more preferably 320 ° C. or less, and more preferably 300 ° C. or less. More preferably. Moreover, it is preferable that the glass transition temperature of a thermoplastic resin component is 50 degreeC or more, It is more preferable that it is 100 degreeC or more, It is further more preferable that it is 150 degreeC or more.

  In the present disclosure, the glass transition temperature can be measured using a differential scanning calorimeter (DSC).

  The shape of the thermoplastic resin component is not particularly limited, and examples thereof include particles, rods, plates, and fibers. Among these, the shape of the thermoplastic resin component is preferably fibrous (thermoplastic resin fiber) because it becomes possible to easily form a non-woven fabric with reinforcing fibers.

  The fiber length of the thermoplastic resin fiber is not particularly limited, and is preferably 1 mm or more, more preferably 3 mm or more, and further preferably 5 mm or more from the viewpoint of the strength of the nonwoven fabric. The fiber length of the thermoplastic resin fiber is preferably 100 mm or less, more preferably 80 mm or less, and further preferably 50 mm or less from the viewpoint of papermaking property.

  The fiber diameter of the thermoplastic resin fiber is not limited, and is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more from the viewpoint of the strength of the nonwoven fabric. The fiber diameter of the thermoplastic resin fiber is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less from the viewpoint of papermaking properties.

  The mass-based content ratio (thermoplastic resin component / reinforced fiber) of the thermoplastic resin component and the reinforcing fiber contained in the mixed nonwoven fabric is not particularly limited, and may be 0.1 / 1 to 20/1. Preferably, it is 1/1 to 10/1, more preferably 2/1 to 6/1.

The volume-based content ratio (Vf (%)) of the reinforcing fibers in the total of the thermoplastic resin component and the reinforcing fibers contained in the mixed nonwoven fabric is preferably 10% by volume to 40% by volume, preferably 12% by volume to More preferably, it is 30% by volume.
When Vf is high, the strength of the fiber-reinforced thermoplastic resin material tends to be improved.

The mixed nonwoven fabric may contain other components other than the reinforcing fiber and the thermoplastic resin component.
Examples of the other component include a binder component for binding the reinforcing fiber and the thermoplastic resin component to improve the strength of the mixed nonwoven fabric.
As binder components, thermosetting resins such as phenol resin, urea resin, melamine resin, unsaturated polyester, epoxy resin, polypropylene, polyethylene, polyester, acrylic resin, styrene-acrylic copolymer, ethylene-vinyl acetate copolymer And thermoplastic resins such as polyurethane, polyvinyl alcohol that melts with hot water, and cellulose nanofibers.
Among these, as a binder component, it is preferable that it is a cellulose nanofiber from a viewpoint of the adhesiveness of a reinforced fiber.
The thermoplastic resin component described above may also function as a binder (binder component) for reinforcing fibers contained in the mixed nonwoven fabric. In this case, the binder component may not be added separately to the mixed nonwoven fabric.

  When the mixed nonwoven fabric includes a binder component, the content of the binder component is preferably 0.1% by mass to 10% by mass with respect to the total amount of the reinforcing fiber and the thermoplastic resin component, and 0.5% by mass to It is more preferably 8% by mass, and further preferably 1% by mass to 5% by mass.

The manufacturing method of the mixed nonwoven fabric prepared in the preparation step is not particularly limited, and for example, a dry method and a wet method can be used.
In the dry method, a web-like nonwoven fabric is produced from reinforcing fibers and a fibrous thermoplastic resin component using a card machine or an air random machine.
In the wet process, the reinforcing fiber, the thermoplastic resin component and, if necessary, the binder component, dispersant, thickener, antifoaming agent, etc. are dispersed in a dispersion medium such as water, and then the dispersion medium is removed to remove the web. A non-woven fabric is produced. The mixed non-woven fabric used in the method for producing a fiber-reinforced thermoplastic resin material of the present disclosure includes a reinforcing fiber, a thermoplastic resin component, a dispersion medium, and a binder component, a dispersant, a thickener, an antifoaming agent, and the like as necessary. It may be obtained by making a fiber slurry containing it.
The manufacturing method of the mixed paper nonwoven fabric by the wet method will be described in detail in the section of the manufacturing method of the mixed paper nonwoven fabric of the present disclosure described later.

The average thickness of the mixed nonwoven fabric is not particularly limited. The average thickness of the mixed nonwoven fabric is preferably 10 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more, from the viewpoint of the handleability of the nonwoven fabric. Moreover, the upper limit of the average thickness of a mixed nonwoven fabric is not specifically limited, For example, 2000 micrometers or less may be sufficient, 1000 micrometers or less may be sufficient, and 500 micrometers or less may be sufficient.
In the present disclosure, the average thickness can be calculated as an arithmetic average value by measuring the thickness of 9 points using a micrometer (for example, Mitutoyo Corporation, Micrometer IP65).

The mass per unit area (weight per unit area) of the mixed nonwoven fabric is not particularly limited. Mass per unit area of混抄nonwoven is ^{preferably 10g / m 2 ~200g / m 2} , more preferably from ^{50g / m 2 ~150g / m 2} , 80g / m 2 ~120g / m 2 More preferably.

-Lamination process-
In the lamination step, a laminated body is obtained by laminating the mixed nonwoven fabrics.
The number of laminated layers when the mixed nonwoven fabric is laminated in the thickness direction of the nonwoven fabric is not particularly limited, and can be appropriately set in consideration of the thickness of the fiber reinforced thermoplastic resin material and the thickness of the mixed nonwoven fabric.
The types of laminated nonwoven fabrics to be laminated may be the same or different. Here, the different types of the mixed nonwoven fabric means that the types of reinforcing fibers and thermoplastic resin components contained in the mixed nonwoven fabric, the average thickness of the mixed nonwoven fabric, the mass per unit area, the value of density, etc. are different. .

-Heating and pressing process-
In the heating and pressing step, the laminate is heated and pressurized. By heating and pressurizing the laminate, the thermoplastic resin component in the mixed nonwoven fabric is melted, and the reinforcing fiber and the thermoplastic resin component are integrated to obtain a fiber-reinforced thermoplastic resin material.

The heating conditions for the laminate are not particularly limited, and can be set in consideration of the content of the thermoplastic resin component contained in the mixed nonwoven fabric, the glass transition temperature, and the like.
The heating temperature in the heating and pressurizing step depends on the type of thermoplastic fiber used, but is preferably 100 ° C to 350 ° C, more preferably 150 ° C to 300 ° C, and 200 ° C to 300 ° C. More preferably it is. If heating temperature is 350 degrees C or less, it exists in the tendency for deterioration of the resin by heating to be suppressed. If the heating temperature is 100 ° C. or higher, the occurrence of molding defects tends to be suppressed.

The pressure condition of the laminate is not particularly limited, and can be set in consideration of the content of the thermoplastic resin component contained in the mixed nonwoven fabric, the glass transition temperature, and the like.
The pressurizing condition in the heating and pressurizing step is preferably 0.5 MPa to 30 MPa, more preferably 1 MPa to 15 MPa, and further preferably 3 MPa to 8 MPa.

  The treatment time in the heating and pressing step is preferably 5 minutes to 120 minutes, more preferably 15 minutes to 60 minutes, and further preferably 20 minutes to 40 minutes.

<Production method of blended nonwoven fabric>
The manufacturing method of the mixed paper nonwoven fabric of this indication has the papermaking process which makes the fiber slurry containing a reinforced fiber, a thermoplastic resin component, and a dispersion medium. In the manufacturing method of the fiber reinforced thermoplastic resin material of the present disclosure, a mixed nonwoven fabric manufactured by the manufacturing method of the mixed nonwoven fabric of the present disclosure may be used.

  The fiber slurry includes reinforcing fibers, a thermoplastic resin component, and a dispersion medium, and may include other components such as a binder component, a dispersant, a thickener, and an antifoaming agent as necessary. The details of the reinforcing fiber, the thermoplastic resin component and the binder component contained in the fiber slurry are as described above.

The paper making apparatus used for paper slurry production is not particularly limited. The papermaking apparatus includes a papermaking net connected in a belt shape, belt driving means for continuously rotating the beltlike papermaking net, a supply means for supplying fiber slurry to the papermaking net, and a web formed on the papermaking net. There may be provided a dehydrating means for dehydrating the water and other means if necessary.
When making a fiber slurry, most of the reinforcing fibers and thermoplastic resin components contained in the fiber slurry are recovered as non-woven fabrics at the time of making paper, so the reinforcing fibers and thermoplastic resin components contained in the fiber slurry The ratio and the ratio of the reinforcing fiber and the thermoplastic resin component contained in the nonwoven fabric are almost the same. On the other hand, other components such as a binder component, a dispersant, a thickener, and an antifoaming agent that are included in the fiber slurry as needed may not be recovered on the papermaking net. Therefore, the ratio of other components contained in the fiber slurry may not match the ratio of other components contained in the nonwoven fabric.

  The total content of the reinforcing fiber and the thermoplastic resin component contained in the fiber slurry is not particularly limited. From the viewpoint of dispersibility and papermaking efficiency, the total content of the reinforcing fiber and the thermoplastic resin component contained in the fiber slurry is preferably 0.001% by mass to 1% by mass, and 0.01% by mass to 0%. More preferably, it is 0.5 mass%, and it is further more preferable that it is 0.02 mass%-0.1 mass%.

  The dispersion medium contained in the fiber slurry is preferably water. You may add organic solvents, such as alcohol and ketones, to a dispersion medium as needed.

  When the fiber slurry contains a binder component, the content of the binder component is preferably 0.00001 mass% to 0.01 mass%, more preferably 0.0001 mass% to 0.005 mass%. Preferably, it is 0.0002 mass% to 0.001 mass%.

The fiber slurry may contain a dispersant. It exists in the tendency for the dispersibility of the reinforced fiber in a nonwoven fabric to improve because fiber slurry contains a dispersing agent. By improving the dispersibility of the reinforced fibers in the nonwoven fabric, variations in the elastic modulus within the surface of the fiber reinforced thermoplastic resin material tend to be suppressed.
The dispersant is not particularly limited as long as it can disperse reinforcing fibers and can be dissolved in a dispersion medium, and a surfactant, a synthetic polymer, or a natural polymer can be used.
Specifically, examples of the surfactant include sodium dodecyl sulfonate, sodium deoxycholate, sodium cholate, sodium dodecylbenzene sulfonate, and the like.
Synthetic polymers include polyether diol, polyester diol, polycarbonate diol, polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetyl group modified polyvinyl alcohol, acetal group modified polyvinyl alcohol, butyral group modified polyvinyl alcohol, silanol group modified polyvinyl alcohol, ethylene -Vinyl alcohol copolymer, ethylene-vinyl alcohol-vinyl acetate copolymer, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, acrylic resin, epoxy resin, modified epoxy resin, phenoxy resin, modified phenoxy resin, phenoxy ether Resin, phenoxy ester resin, fluorine resin, melamine resin, alkyd resin, phenol resin, polyacrylamid , Polyacrylic acid, polystyrene sulfonic acid, polyethylene glycol, polyvinylpyrrolidone, and the like.
Natural polymers include polysaccharides such as starch, pullulan, dextran, dextrin, guar gum, xanthan gum, amylose, amylopectin, alginic acid, gum arabic, carrageenan, chondroitin sulfate, hyaluronic acid, curdlan, chitin, chitosan, cellulose, Examples thereof include salts and derivatives thereof. The “derivative” means a conventionally known compound such as ester or ether.
These dispersants may be used alone or in combination of two or more.

  The content of the dispersant is preferably 0.1% by mass or more, and more preferably 1% by mass or more, with respect to the total mass of the reinforcing fiber and the thermoplastic resin component contained in the fiber slurry. Moreover, it is preferable that the content rate of a dispersing agent is 15 mass% or less, and it is more preferable that it is 12 mass% or less.

The fiber slurry may contain a thickener. When the fiber slurry contains a thickener, the dispersion stability of the fiber slurry tends to be improved.
Examples of the thickener include anionic polyacrylamide and nonionic polyethylene oxide.

  The content of the thickener is preferably 0.1% by mass or more and 0.3% by mass or more with respect to the total mass of the reinforcing fiber and the thermoplastic resin component contained in the fiber slurry. More preferred. Moreover, it is preferable that the addition amount of a thickener is 5 mass% or less. If the content rate of a thickener is 0.1 mass% or more, it exists in the tendency for the function of a thickener to be expressed easily. If the content of the thickener is 5% by mass or less, there is a tendency that lumps are not easily generated in the fiber slurry.

The fiber slurry may contain an antifoaming agent. When the fiber slurry contains an antifoaming agent, the papermaking property tends to be improved.
Examples of the antifoaming agent include silicone-based antifoaming agents, hydrophobic silica, hydrophobic silicone, wax, polysiloxane and the like.

  The paper making speed (fiber slurry conveying speed) when making the fiber slurry is appropriately set in consideration of the amount of reinforcing fiber and thermoplastic resin component contained in the fiber slurry, the type of the paper making apparatus, the thickness of the nonwoven fabric, and the like. An example of the papermaking speed is preferably 1 m / min to 20 m / min, and more preferably 5 m / min to 10 m / min.

The fiber slurry can be prepared by mixing the reinforcing fiber, the thermoplastic resin component, the dispersion medium, and other components such as a binder component, a dispersant, a thickener, and an antifoaming agent used as necessary. . When the reinforcing fiber and the thermoplastic resin component are fibrous, the fibrous thermoplastic resin component may be subjected to disaggregation using a disaggregator.
In the case where the reinforcing fibers and the fibrous thermoplastic resin component are disaggregated, the reinforcing fibers and the fibrous thermoplastic resin component may be separately disaggregated and then mixed together.

The viscosity of the fiber slurry is not particularly limited, and is preferably 1 Pa · s to 10 Pa · s at 25 ° C., more preferably 1 Pa · s to 5 Pa · s.
The viscosity of the fiber slurry can be set to a desired range by appropriately adjusting the content of reinforcing fibers and thermoplastic resin components, the type of thickener, the content of thickener, and the like.

  A mixed nonwoven fabric can be obtained by drying the web obtained by making the fiber slurry. The conditions for drying the web are not particularly limited. The drying temperature is preferably 80 ° C to 150 ° C, more preferably 100 ° C to 120 ° C, and further preferably 100 ° C to 110 ° C. The drying time is preferably 2 minutes to 120 minutes, more preferably 5 minutes to 45 minutes, and even more preferably 10 minutes to 40 minutes.

<Fiber-reinforced thermoplastic resin material>
The fiber reinforced thermoplastic resin material of the present disclosure has the following formula from the number A of reinforcing fibers to which the thermoplastic resin component is attached and the number B of reinforcing fibers to which the thermoplastic resin component is not attached when the fracture surface is observed. The adhesion rate obtained based on is 30% or more.
Adhesion rate (%) = [A / (A + B)] × 100
The fiber reinforced thermoplastic resin material of the present disclosure may be manufactured by the method for manufacturing the fiber reinforced thermoplastic resin material of the present disclosure.

In the present disclosure, a fiber-reinforced thermoplastic resin material cut to 2.5 cm × 4.0 cm is used with a 5-ton tensilon (RTC-1350A) manufactured by Orientec Corporation at room temperature (25 ° C.) and a crosshead speed of 3. A three-point bending test was performed under the condition of 8 mm / min, and the adhesion rate was calculated for the exposed fracture surface.
Details of the method for calculating the adhesion rate are as follows.
The fiber reinforced thermoplastic resin material is folded to expose the fracture surface. This fracture surface is observed with a scanning electron microscope. In the observation image, at least one of the reinforcing fiber to which the thermoplastic resin component is attached and the reinforcing fiber to which the thermoplastic resin component is not attached is observed as a projected image. The ratio [A / (A + B)] of the number A of reinforcing fibers to which the thermoplastic resin component adheres in the total number (A + B) of all reinforcing fibers observed is calculated as the adhesion rate.
“The thermoplastic resin component is“ attached ”to the reinforcing fiber” means that the thermoplastic resin component is present in 30% or more of the surface of the reinforcing fiber on the basis of the area of the observation image (projected image). On the other hand, “the thermoplastic resin component is not attached” to the reinforcing fiber means that the thermoplastic resin component is present in less than 30% of the surface of the reinforcing fiber on the basis of the area of the observation image (projected image), or This means that no thermoplastic resin component is present on the surface of the reinforcing fiber.

Two fracture modes are considered to occur at the fractured surface exposed by bending the fiber reinforced thermoplastic resin material. One is a state in which the reinforcing fiber and the thermoplastic resin component peel at the interface between the reinforcing fiber and the thermoplastic resin component. The other is a state in which the thermoplastic resin component itself is destroyed inside the thermoplastic resin component. When the reinforcing fiber and the thermoplastic resin component are peeled off, the surface of the reinforcing fiber is exposed, so that the reinforcing fiber corresponds to a reinforcing fiber to which the thermoplastic resin component is not attached. On the other hand, when the thermoplastic resin component itself is destroyed inside the thermoplastic resin component, the thermoplastic resin component remains attached to the surface of the reinforcing fiber, so this reinforcing fiber is reinforced with the thermoplastic resin component attached. It corresponds to fiber. That is, the adhesion rate is considered to be a value proportional to the ratio of the state in which the thermoplastic resin component itself is destroyed within the thermoplastic resin component occupying all the fracture modes in the fracture surface.
The state where the separation between the reinforcing fiber and the thermoplastic resin component occurs at the interface between the reinforcing fiber and the thermoplastic resin component is compared to the state where the thermoplastic resin component itself is destroyed inside the thermoplastic resin component. This suggests that the adhesion between the reinforcing fiber and the thermoplastic resin component is poor.
As a result of intensive studies, the inventors have a correlation between the elastic modulus and the adhesion rate of the fiber-reinforced thermoplastic resin material, and the adhesion between the reinforcing fiber and the thermoplastic resin component (that is, the adhesion rate). ) Is low, the elastic modulus of the fiber-reinforced thermoplastic resin material is found to deteriorate. And if the adhesion rate was 30% or more, it came to the conclusion that sufficient elasticity modulus can be ensured as a fiber reinforced thermoplastic resin material.

  The adhesion rate is preferably 45% or more, and more preferably 60% or more. The upper limit of the adhesion rate is 100%.

  The average thickness and basis weight of the fiber-reinforced thermoplastic resin material can be adjusted, for example, by adjusting the average thickness and basis weight of the blended nonwoven fabric, the number of layers of the blended nonwoven fabric, and the heating and pressing conditions of the laminate. .

<Structure>
The structure of the present disclosure is configured by a part or all of the fiber reinforced thermoplastic resin material manufactured by the method of manufacturing the fiber reinforced thermoplastic resin material of the present disclosure or the fiber reinforced thermoplastic resin material of the present disclosure. is there.
Since the structure of the present disclosure is partially or entirely composed of the fiber reinforced thermoplastic resin material manufactured by the method of manufacturing the fiber reinforced thermoplastic resin material of the present disclosure or the fiber reinforced thermoplastic resin material of the present disclosure. Excellent elasticity.

  When forming a structure using a fiber reinforced thermoplastic resin material, it is preferable to mold the fiber reinforced thermoplastic resin material at a temperature equal to or higher than the glass transition temperature of the thermoplastic resin component. As an apparatus used for heat-pressure molding, a press machine etc. are mentioned, for example. Although it depends on the kind of the thermoplastic resin component, the heating condition is preferably 50 ° C to 350 ° C, more preferably 200 ° C to 300 ° C. Although it depends on the kind of the thermoplastic resin component, the pressurizing condition is preferably 1 MPa or more. Further, the heating and pressing time is preferably 1 minute to 60 minutes, more preferably 3 minutes to 40 minutes, and more preferably 10 minutes to 30 minutes, although it depends on the type of the thermoplastic resin component. More preferably. The rate of temperature increase until reaching a predetermined heating temperature is preferably 1 ° C./min to 30 ° C./min, although it depends on the type of thermoplastic resin component, and is 5 ° C./min to 30 ° C./min. More preferably. The cooling temperature after completion of the heating and pressing treatment is preferably 5 ° C./min to 30 ° C./min, preferably 10 ° C./min to 20 ° C./min, although it depends on the type of thermoplastic resin component. Is more preferable. During cooling, it is preferable to maintain a pressurized state of the fiber reinforced thermoplastic resin material.

  The structure of the present disclosure can be suitably used as a structure constituting an automobile-related part, a home appliance part, or the like.

  Hereinafter, the present invention will be described in more detail based on examples. The present invention is not limited to the following examples.

[Example 1]
(Preparation of mixed nonwoven fabric)
-Preparation of fiber slurry-
0.4 parts by mass of carbon fiber having a fiber diameter of 10 μm and a fiber length of 10 mm, and 1.6 parts by mass of polyamide fiber (nylon fiber, glass transition temperature: 280 ° C.) having a fiber diameter of 10 μm and a fiber length of 10 mm 0.02 parts by mass of cellulose nanofibers having a fiber diameter of 0.1 μm and a fiber length of 10 μm, 0.1 parts by mass of CP-B2 (dispersing agent) manufactured by Meisei Chemical Co., Ltd. 0.04 parts by mass of S-300 (thickening agent) is added to water, and Fossil P-98 (antifoaming agent) manufactured by Meisei Chemical Co., Ltd. is an amount necessary to exert an antifoaming effect. A fiber slurry was prepared by adding and stirring to disperse the fiber component in water. The amount of water was 3500 times on a mass basis with respect to the total amount of carbon fiber and nylon fiber (0.03% by mass as the total concentration of carbon fiber and nylon fiber).

-Papermaking-
Using the fiber slurry obtained as described above, a web was formed by a wet method, and heat-dried at 105 ° C. to produce a mixed nonwoven fabric having a basis weight of 100 g / m ² . Vf of the mixed nonwoven fabric was 15% by volume.

(Manufacture of fiber reinforced thermoplastic resin materials)
20 sheets of the obtained mixed nonwoven fabric were laminated to obtain a laminate. This laminate was pressed at 260 ° C. and 5 MPa for 30 minutes to obtain a fiber-reinforced thermoplastic resin material.
The following evaluation was implemented using the obtained fiber reinforced thermoplastic resin material.

(Measurement of elastic modulus)
A fiber-reinforced thermoplastic resin material cut to 2.5 cm × 4.0 cm is used with a 5-ton tensilon (RTC-1350A) manufactured by Orientec Co., Ltd., at room temperature (25 ° C.), and a crosshead speed of 3.8 mm / min. A three-point bending test was performed under the conditions, and the elastic modulus was measured. The measurement was performed at 10 points, the average value being the elastic modulus, and the difference between the maximum and minimum values being the elastic modulus variation.

(Observation of fracture surface)
An electron micrograph (1000 times) of the fracture surface of the fiber-reinforced thermoplastic resin material after the three-point bending test was taken using a scanning electron microscope JSM-7800F-Prime manufactured by JEOL Ltd. An example of the electron micrograph of the obtained fracture surface is shown in FIG. In FIG. 1, carbon fibers (A) having a thermoplastic resin component attached to the surface and carbon fibers (B) having no thermoplastic resin component attached to the surface were observed.
By the above method, the adhesion rate for the fiber-reinforced thermoplastic resin material of Example 1 was calculated to be 60%.

[Example 2]
A mixed nonwoven fabric and a fiber reinforced thermoplastic resin material were obtained in the same manner as in Example 1 except that the dispersant was not used. The basis weight of the mixed nonwoven fabric was 100 g / m ² and Vf was 15% by volume.
Evaluation was performed in the same manner as in Example 1 using the obtained fiber-reinforced thermoplastic resin material. In FIG. 2, an example of the electron micrograph of the torn surface about the fiber reinforced thermoplastic resin material of Example 2 is shown.
By the said method, the adhesion rate about the fiber reinforced thermoplastic resin material of Example 2 was calculated to be 60%.

[Comparative Example 1]
(Preparation of carbon fiber nonwoven fabric)
-Preparation of carbon fiber slurry-
2.0 mass parts of carbon fibers having a fiber diameter of 10 μm and a fiber length of 10 mm, 0.02 mass parts of cellulose nanofibers having a fiber diameter of 0.1 μm and a fiber length of 10 μm, CP- manufactured by Meisei Chemical Co., Ltd. 0.12 parts by mass of B2 (dispersing agent) and 0.05 part by mass of Pamall S-300 (thickener) manufactured by Meisei Chemical Co., Ltd. are added to water, and Foamless P- produced by Meisei Chemical Co., Ltd. 98 (antifoaming agent) was added in an amount necessary for exhibiting the defoaming effect, and stirred to prepare a carbon fiber slurry in which fiber components were dispersed in water. The amount of water was 3500 times on a mass basis with respect to the carbon fiber (0.03% by mass as the concentration of carbon fiber).

-Papermaking-
A carbon fiber nonwoven fabric having a basis weight of 100 g / m ² was prepared by forming a web by a wet method using the carbon fiber slurry obtained as described above and drying by heating at 105 ° C.

-Preparation of nylon fiber slurry-
2.0 parts by mass of a polyamide fiber (nylon fiber, glass transition temperature: 280 ° C.) having a fiber diameter of 10 μm and a fiber length of 10 mm, and 0.02 of cellulose nanofiber having a fiber diameter of 0.1 μm and a fiber length of 10 μm Part by mass and 0.4 part by mass of Meisei Chemical Co., Ltd. Pamall S-300 (thickener) are added to the water, and Foamless P-98 (foaming agent) made by Meisei Chemical Co., Ltd. is turned off. A nylon fiber slurry was prepared by adding an amount necessary for exhibiting the foam effect, stirring, and dispersing the fiber component in water. The amount of water was 3500 times based on the mass of nylon fibers (0.03% by mass as the concentration of nylon fibers).

-Papermaking-
A nylon fiber nonwoven fabric having a basis weight of 100 g / m ² was produced by forming a web by a wet method using the nylon fiber slurry obtained as described above and drying by heating at 105 ° C.

(Manufacture of fiber reinforced thermoplastic resin materials)
Four carbon fiber non-woven fabrics and 16 nylon fiber non-woven fabrics were laminated in the order of nylon fiber non-woven fabric-nylon fiber non-woven fabric-carbon fiber non-woven fabric-nylon fiber non-woven fabric-nylon fiber non-woven fabric, and a total of 4 sets were laminated. To obtain a laminate. This laminate was pressed at 260 ° C. and 5 MPa for 30 minutes to obtain a fiber-reinforced thermoplastic resin material. Evaluation was performed in the same manner as in Example 1 using the obtained fiber-reinforced thermoplastic resin material. In FIG. 3, an example of the electron micrograph of the torn surface about the fiber reinforced thermoplastic resin material of the comparative example 1 is shown.
By the above method, the adhesion rate for the fiber-reinforced thermoplastic resin material of Comparative Example 1 was calculated to be 10%.

  From Table 1, the fiber reinforced thermoplastic resin material of the example manufactured using the mixed nonwoven fabric is compared with the fiber reinforced thermoplastic resin material of the comparative example manufactured by alternately stacking the carbon fiber nonwoven fabric and the nylon fiber nonwoven fabric. And the elastic modulus is excellent. In addition, the fiber reinforced thermoplastic resin material of Example 1 using the dispersant in the preparation of the fiber slurry was replaced with the fiber reinforced thermoplastic resin material of Example 2 in which the dispersant was not used in the preparation of the fiber slurry. In comparison, the variation in elastic modulus was small. In addition, the elasticity modulus of the fiber reinforced thermoplastic resin material of the Example manufactured using the mixed nonwoven fabric was equivalent irrespective of whether the dispersing agent was used in the preparation of the fiber slurry.

Claims (6)

A preparation step of preparing a non-woven fabric containing a reinforcing fiber and a thermoplastic resin component;
Laminating step of laminating the mixed nonwoven fabric to obtain a laminate,
A heating and pressurizing step of heating and pressurizing the laminate;
The manufacturing method of the fiber reinforced thermoplastic resin material which has this.   The method for producing a fiber-reinforced thermoplastic resin material according to claim 1, wherein the mixed nonwoven fabric is obtained by making a fiber slurry containing the reinforcing fibers, the thermoplastic resin component, and a dispersion medium.   The method for producing a fiber-reinforced thermoplastic resin material according to claim 1, wherein the thermoplastic resin component is fibrous.   A method for producing a mixed non-woven fabric comprising a paper making step for making a fiber slurry containing reinforcing fibers, a thermoplastic resin component and a dispersion medium. When the fracture surface is observed, the adhesion rate obtained from the following formula from the number A of reinforcing fibers to which the thermoplastic resin component is attached and the number B of reinforcing fibers to which the thermoplastic resin component is not attached is 30%. This is the fiber reinforced thermoplastic resin material.
Adhesion rate (%) = [A / (A + B)] × 100   A part of the fiber reinforced thermoplastic resin material produced by the method for producing a fiber reinforced thermoplastic resin material according to any one of claims 1 to 3 or the fiber reinforced thermoplastic resin material according to claim 5. Or a structure that is entirely constructed.