JP6972611B2 - Reinforcing fiber composite material and manufacturing method of reinforcing fiber composite material - Google Patents

Description

The present invention relates to a reinforcing fiber composite material and a method for producing a reinforcing fiber composite material.

For example, structural materials used in aircraft, automobiles, and the like are required to be further reduced in weight.

As such a structural material, for example, a fiber reinforced resin made by mixing a reinforcing fiber such as glass fiber and a resin is known. In such a fiber reinforced resin, the fibers are entwined with each other in all three-dimensional directions to reinforce the fiber as a whole.

Specifically, it has been proposed to increase the strength of the structural material by using a papermaking body (composite molded body) (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 4-174793

However, it is difficult to make the structure different on the front and back of a reinforcing fiber composite material such as a papermaking body because the whole tends to be homogeneous due to the characteristics of the manufacturing method.

On the other hand, making the structure different on the front and back contributes to higher functionality of the structural material and leads to an increase in added value. For example, a reinforcing fiber composite material having different thermal, electrical, and mechanical properties on the front and back is considered to be useful as a mounting substrate on which different electronic elements are mounted on the front and back.

An object of the present invention is to provide a reinforcing fiber composite material having different surface physical properties on the front and back surfaces, and a method for producing a reinforcing fiber composite material capable of efficiently producing such a reinforcing fiber composite material.

Such an object is achieved by the present invention of the following (1) to (6).
(1) Ri Na bundled plurality of single fibers, a first fiber bundle Ru der 5 times or more the average diameter of the width monofilament,
A second fiber bundle in which a plurality of single fibers are bundled and the width is less than 5 times the average diameter of the single fibers.
With resin
The have including papermaking product,
The average length of the first fiber bundle and the second fiber bundle is 100 mm or less, and the average length is 100 mm or less.
Of the two surfaces on the front and back relationship with each other, the area ratio occupied by the first fiber bundle at one side and A1 [%], the area fraction of an Oite the first fiber bundles on the other surface A2 [ %], The reinforcing fiber composite material is characterized in that A1-A2 is 10 to 90%.

(2) The reinforcing fiber composite material according to (1) above, wherein the first fiber bundle and the second fiber bundle have an average length of 5 mm or more.

(3) The reinforcing fiber composite material according to (1) or (2) above, wherein the single fiber is an inorganic fiber or an organic fiber.

(4) The reinforcing fiber composite material according to any one of (1) to (3) above, wherein the resin is a thermosetting resin.

(5) B2-B1 when the area ratio occupied by the second fiber bundle on one surface is B1 [%] and the area ratio occupied by the second fiber bundle on the other surface is B2 [%]. The reinforcing fiber composite material according to any one of (1) to (4) above, wherein the content is 10 to 90%.

(6) Preparation width and first fiber bundle 5 times or more the average diameter of single fiber, the second fiber bundle is less than 5 times the average diameter of width of monofilament, is dispersed in a dispersion medium, a dispersion And the process to do
A step of making an elementary form from the dispersion while precipitating the second fiber bundle in the dispersion.
A step of obtaining a manuscript molded body having two surfaces which are in a front-to-back relationship with each other by pressure molding while heating the element body.
Have a,
Of the two surfaces, when the area ratio occupied by the first fiber bundle on one surface is A1 [%] and the area ratio occupied by the first fiber bundle on the other surface is A2 [%], A1. -A method for producing a reinforcing fiber composite material, characterized in that A2 is 10 to 90%.

According to the present invention, a reinforcing fiber composite material having different surface physical properties on the front and back can be obtained.
Further, according to the present invention, the reinforcing fiber composite material can be efficiently manufactured.

It is a perspective view which shows the embodiment of the reinforcing fiber composite material of this invention. It is a figure for demonstrating an example (papermaking method) of the method of manufacturing the reinforcing fiber composite material shown in FIG. It is a figure for demonstrating an example (papermaking method) of the method of manufacturing the reinforcing fiber composite material shown in FIG. It is a figure for demonstrating an example (papermaking method) of the method of manufacturing the reinforcing fiber composite material shown in FIG. It is a figure for demonstrating an example (papermaking method) of the method of manufacturing the reinforcing fiber composite material shown in FIG. It is a figure for demonstrating an example (papermaking method) of the method of manufacturing the reinforcing fiber composite material shown in FIG.

Hereinafter, the reinforcing fiber composite material and the method for producing the reinforcing fiber composite material of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

<Reinforced fiber composite material>
First, an embodiment of the reinforcing fiber composite material of the present invention will be described.
FIG. 1 is a perspective view showing an embodiment of the reinforcing fiber composite material of the present invention.

The reinforcing fiber composite material 1 shown in FIG. 1 has a sheet shape, and its main surface has a rectangular shape in a plan view. Of the two surfaces of the reinforcing fiber composite material 1 shown in FIG. 1, which are in a front-to-back relationship with each other, one surface is referred to as the first surface 11 and the other surface is referred to as the second surface 12. Note that FIG. 1 (a) shows the reinforcing fiber composite material 1 so that the first surface 11 faces the upper surface, and FIG. 1 (b) shows the reinforcing fiber composite material 1 shown in FIG. 1 (a). Is shown upside down, and the reinforcing fiber composite material 1 is shown so that the second surface 12 is on the upper surface.

The reinforcing fiber composite material 1 shown in FIG. 1 includes a resin 2 and a fiber bundle 3 in which a plurality of single fibers are bundled. Among the fiber bundles 3, those having a width of 5 times or more the average diameter of the single fiber are referred to as "first fiber bundle 31", and those having a width less than 5 times the average diameter of the single fiber are referred to as "second fiber bundle". 32 ”, the area ratio occupied by the relatively wide first fiber bundle 31 on the first surface 11 (one surface) among the two surfaces of the reinforcing fiber composite material 1 which are in a front-to-back relationship with each other is determined. It is 10% or more larger than the area ratio occupied by the first fiber bundle 31 on the second surface 12 (the other surface) (see FIG. 1).

In such a reinforcing fiber composite material 1, since the resin 2 is reinforced by the first fiber bundle 31 and the second fiber bundle 32, high mechanical strength can be obtained in spite of being lightweight.

Further, since the area ratio occupied by the first fiber bundle 31 is different between the first surface 11 and the second surface 12, the physical characteristics of the surface are also different. For example, a reinforcing fiber composite material 1 having different thermal conductivity, conductivity, surface hardness, etc. between the first surface 11 and the second surface 12 can be obtained. Therefore, the reinforcing fiber composite material 1 has the added value of having different physical properties on the front and back while taking advantage of the characteristics of being lightweight and having high mechanical strength.

The shape of the reinforcing fiber composite material 1 is not limited to a sheet shape as long as it has a first surface 11 and a second surface 12 which are in a front-to-back relationship with each other. It may have any shape.

Hereinafter, the components constituting the reinforcing fiber composite material 1 will be described in detail.
(resin)
The resin 2 imparts moldability and shape retention to the reinforcing fiber composite material 1 and functions as a binder for binding the fiber bundles 3 to each other. Therefore, the resin 2 is not particularly limited as long as it has such a function. For example, phenolic resin, epoxy resin, unsaturated polyester resin, melamine resin, thermosetting resin such as polyurethane, polyamide resin (for example, nylon), thermoplastic urethane resin, polyolefin resin (for example, polyethylene). , Polypropylene, etc.), Polycarbonate, polyester resin (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), polyacetal, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, fluororesin (eg, polytetrafluoroethylene, polyvinylidene fluoride, etc.), modification Examples thereof include thermoplastic resins such as polyphenylene ether, polysulfone, polyether sulfone, polyarylate, polyamideimide, polyetherimide, and thermoplastic polyimide. The resin 2 may contain at least one of these, or may contain two or more of them.

The resin 2 preferably contains a thermosetting resin. Thereby, the mechanical properties and heat resistance of the reinforcing fiber composite material 1 can be further enhanced.

Further, the resin 2 preferably contains at least one of a phenol-based resin, an epoxy-based resin and a bismaleimide resin. Thereby, the mechanical properties and heat resistance of the reinforcing fiber composite material 1 can be particularly enhanced.

Examples of the phenol resin include a novolak-type phenol resin such as a phenol novolac resin, a cresol novolak resin, a bisphenol A novolak resin, and an arylalkylene-type novolak resin, an unmodified resolephenol resin, tung oil, flaxseed oil, and walnut oil. Examples thereof include a resol type phenol resin such as a modified oil-modified resol phenol resin.

Among these, the novolak type phenol resin is preferably used from the viewpoint of cost and moldability.

The weight average molecular weight of the phenol resin is not particularly limited, but is preferably about 1000 to 15000. If the weight average molecular weight of the phenol resin is less than the lower limit, the viscosity of the resin 2 may become too low, making molding difficult during production. On the other hand, if the weight average molecular weight of the phenol resin exceeds the upper limit, the viscosity of the resin 2 may become too high and the moldability at the time of manufacture may deteriorate.

The weight average molecular weight of the phenol resin can be determined as a polystyrene-equivalent weight molecular weight measured by gel permeation chromatography (GPC).

Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type and bisphenol AD type, novolak type epoxy resins such as phenol novolac type and cresol novolak type, brominated bisphenol A type and brominated phenol. Examples thereof include brominated epoxy resin such as novolak type, biphenyl type epoxy resin, naphthalene type epoxy resin, tris (hydroxyphenyl) methane type epoxy resin and the like.

Among these, bisphenol type epoxy resin and novolak type epoxy resin are preferably used from the viewpoint of high fluidity and moldability.

Further, a bisphenol A type epoxy resin having a relatively low molecular weight, a phenol novolac type epoxy resin, and a cresol novolac type epoxy resin are more preferably used.

Further, from the viewpoint of heat resistance, a phenol novolac type epoxy resin and a cresol novolac type epoxy resin are more preferably used, and a tris (hydroxyphenyl) methane type epoxy resin is particularly preferably used.

The bismaleimide resin is not particularly limited as long as it is a resin having maleimide groups at both ends of the molecular chain, but a resin having a benzene ring is preferable, and a resin represented by the following general formula (1) is more preferable. Used.

［式中、Ｒ^１〜Ｒ^４は、置換基を有していてもよい炭素数１〜４の炭化水素基または水素原子を表す。また、Ｒ^５は、２価の有機基を表す。］

[In the formula, R ^{1 to} R ⁴ represent a hydrocarbon group or a hydrogen atom having 1 to 4 carbon atoms which may have a substituent. Further, R ⁵ represents a divalent organic group. ]

However, the bismaleimide resin may have a maleimide group other than both ends of the molecular chain.

Here, the organic group is a hydrocarbon group which may contain an atom other than a carbon atom, and examples of the atom other than the carbon atom include O, S, N and the like.

R ⁵ is not preferably has a main chain structure a methylene group and an aromatic ring and an ether bond (-O-) and are bonded in any order, at least one of the substituents and the side chain on the backbone You may. The total number of methylene groups, aromatic rings and ether bonds contained in the main chain structure is 15 or less. Examples of the above-mentioned substituent or side chain include a hydrocarbon group having 3 or less carbon atoms, a maleimide group, a phenylene group and the like.

Examples of the bismaleimide resin include N, N'-(4,4'-diphenylmethane) bismaleimide, bis (3-ethyl-5-methyl-4-maleimidephenyl) methane, and 2,2-bis [4- ( 4-maleimide phenoxy) phenyl] propane, m-phenylene bismaleimide, p-phenylene bismaleimide, 4-methyl-1,3-phenylene bismaleimide, N, N'-ethylenedimaleimide, N, N'-hexamethylenedi Maleimide and the like can be mentioned.

Further, a curing agent is used in combination with the resin 2 as needed.
For example, when a novolak type phenol resin is used as the resin 2, hexamethylenetetramine is usually used as the curing agent.

Further, for example, when an epoxy resin is used as the resin 2, the curing agent may be an aliphatic polyamine, an aromatic polyamine, an amine compound such as disiamine diamide, an alicyclic acid anhydride, or an aromatic acid anhydride. Acid anhydride, polyphenol compound such as novolak type phenol resin, imidazole compound and the like are used.

Among these, the novolak type phenol resin is preferably used from the viewpoint of handleability and the environment. In particular, when a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and a tris (hydroxyphenyl) methane type epoxy resin are used as the epoxy resin, the heat resistance of the cured product can be more easily improved as the curing agent. Novolac type phenolic resin is preferably used.

Further, for example, when a bismaleimide resin is used as the resin 2, an imidazole compound is used as the curing agent.
As the curing agent, one or more of the above-mentioned ones are used.

On the other hand, the resin 2 may contain a thermoplastic resin in particular. As a result, the moldability of the reinforcing fiber composite material 1 can be particularly improved, and the reinforcing fiber composite material 1 having higher dimensional accuracy can be obtained.

Further, the resin 2 preferably contains a super engineering plastic among the thermoplastic resins. As a result, in addition to the effect brought about by the thermoplastic resin, the effect of high mechanical properties is added. Examples of super engineering plastics include polysulfone, polyether sulfone, polyphenylene sulfide, polyether ether ketone, polyarylate, polyamideimide, polyetherimide, liquid crystal polymer, and fluororesin.

The melting point of the resin 2 is not particularly limited, but is preferably 200 to 400 ° C, more preferably 210 to 390 ° C, and even more preferably 260 to 380 ° C. By using such a resin 2, the mechanical properties and heat resistance of the reinforcing fiber composite material 1 can be sufficiently enhanced. As a result, when the reinforcing fiber composite material 1 is applied to, for example, an interior material for transportation equipment, an interior material having excellent flame retardancy can be obtained.

When the melting point of the resin 2 is lower than the lower limit, the dimensional accuracy of the reinforcing fiber composite material 1 at high temperature may be lowered or the flame retardancy based on heat resistance may be lowered depending on the configuration of the reinforcing fiber composite material 1. There is a risk of On the other hand, the melting point of the resin 2 may exceed the upper limit value, but some physical properties (for example, impact resistance, etc.) may be deteriorated accordingly.

Here, the melting point of the resin 2 is, in principle, the melting point of the crystal, and can be measured by, for example, a differential scanning calorimeter (DSC-2920, manufactured by TA Instruments).

When the resin 2 does not have a crystal melting point and has a glass transition temperature, the melting point of the resin 2 in the present invention also includes the glass transition temperature. This glass transition temperature can also be measured by the above-mentioned differential scanning calorimeter.

Further, when the resin 2 is a thermosetting resin and neither the crystal melting point nor the glass transition temperature exists, the melting point of the resin 2 in the present invention includes the heat resistant temperature of the cured product of the thermosetting resin. This heat resistant temperature is the deflection temperature under load specified in the general test method for thermoplastics of JIS K 6911: 1995.

(1st fiber bundle and 2nd fiber bundle)
The first fiber bundle 31 and the second fiber bundle 32 each contribute to improving the mechanical properties of the reinforcing fiber composite material 1 and improving the thermal conductivity.

The first fiber bundle 31 and the second fiber bundle 32 are, for example, those obtained by cutting a long fiber bundle to a predetermined length and subjected to fiber opening treatment or the like as necessary. be.

Here, as described above, the width of the first fiber bundle 31 is 5 times or more the average diameter of the single fiber in the fiber bundle 3, and the width of the second fiber bundle 32 is the width of the fiber bundle 3. It is less than 5 times the average diameter of a single fiber. Therefore, the first fiber bundle 31 and the second fiber bundle 32 have different thermal, electrical, and mechanical properties from each other. That is, the width of the fiber bundle 3 affects the physical properties such as the conductivity of heat and electrons and the mechanical properties. Therefore, by making the width of the fiber bundle 3 different, these characteristics can be made different as a result. can.

In the reinforcing fiber composite material 1, the area ratio occupied by the first fiber bundle 31 having a width of 5 times or more the average diameter of the single fiber on the first surface 11 (one surface) is the second surface 12 (the other surface). ) Is 10% or more larger than the area ratio occupied by the first fiber bundle 31. Therefore, the first surface 11 of the reinforcing fiber composite material 1 tends to have relatively high thermal, electrical, and mechanical properties. As a result, the reinforcing fiber composite material 1 having a distribution in these characteristics is obtained.

Specifically, the physical properties derived from the first fiber bundle 31 are more strongly reflected on the first surface 11 than on the second surface 12. Therefore, the physical properties such as thermal conductivity, electrical conductivity, and surface hardness of the first surface 11 can be made larger than those of the second surface 12.

On the other hand, in the second surface 12 according to the present embodiment, the area ratio occupied by the first fiber bundle 31 is smaller than that of the first surface 11. Therefore, the physical properties derived from the first fiber bundle 31 are not reflected much on the second surface 12 as compared with the first surface 11. Therefore, the physical properties such as thermal conductivity, electrical conductivity, and surface hardness of the second surface 12 can be made smaller than those of the first surface 11.

When the area ratio occupied by the first fiber bundle 31 on the first surface 11 is A1 and the area ratio occupied by the first fiber bundle 31 on the second surface 12 is A2, A1-A2 is 10% or more. It is preferably 10 to 90%, more preferably 10 to 70%, still more preferably 20 to 50%. A1-A2 can be an index (an index of the degree of uneven distribution) indicating how much the area occupied by the relatively wide first fiber bundle 31 differs between the first surface 11 and the second surface 12. However, when A1-A2 is within the above range, it is possible to prevent the first fiber bundle 31 from being significantly unevenly distributed on the first surface 11 side in the reinforcing fiber composite material 1, and by extension, the physical characteristics of the reinforcing fiber composite material 1 as a whole. It is possible to prevent the balance from being lost.

If A1-A2 is below the lower limit, the difference in area ratio becomes small, so the difference in physical properties between the first surface 11 and the second surface 12 becomes small, and the added value may be impaired. .. On the other hand, if A1-A2 exceeds the upper limit value, the difference in area ratio becomes too large, and for example, the variation in mechanical characteristics becomes large, so that deformation such as warpage may become large.

The area ratios A1 and A2 are obtained by observing the first surface 11 and the second surface 12 with an optical microscope or an electron microscope and calculating the area ratio of the first fiber bundle 31 with respect to the entire observation image.

Further, the width of the first fiber bundle 31 means the maximum width of each first fiber bundle 31 shown in the captured observation image.
The magnification at the time of observation is a magnification at which 10 or more first fiber bundles 31 are captured in the observation image.

On the other hand, when the area ratio occupied by the second fiber bundle 32 on the first surface 11 is B1 and the area ratio occupied by the second fiber bundle 32 on the second surface 12 is B2, it is preferable that B2> B1. Further, B2-B1 is preferably 10 to 90%, more preferably 10 to 70%, and even more preferably 20 to 50%. B2-B1 can be an index (indicator of the degree of uneven distribution) indicating how much the area occupied by the relatively narrow second fiber bundle 32 differs between the first surface 11 and the second surface 12. However, when B1 and B2 are within the above range, it is possible to prevent the second fiber bundle 32 from being remarkably unevenly distributed on the second surface 12 side in the reinforcing fiber composite material 1, and by extension, the physical properties of the reinforcing fiber composite material 1 as a whole. It is possible to prevent the balance from being lost.

If B2-B1 is below the lower limit, the difference in area ratio becomes small, so the difference in physical properties between the first surface 11 and the second surface 12 becomes small, and the added value may be impaired. .. On the other hand, if B2-B1 exceeds the upper limit value, the difference in area ratio becomes too large, and for example, the variation in mechanical characteristics becomes large, so that deformation such as warpage may become large.

The area ratios B1 and B2 are obtained by observing the first surface 11 and the second surface 12 with an optical microscope or an electron microscope and calculating the area ratio of the second fiber bundle 32 with respect to the entire observation image.

Further, the width of the second fiber bundle 32 means the maximum width of each second fiber bundle 32 shown in the captured observation image.
Further, the magnification at the time of observation is a magnification at which 10 or more second fiber bundles 32 are captured in the observation image.

The fibers used as the first fiber bundle 31 and the fibers used as the second fiber bundle 32 may be fibers made of different materials from each other, but are preferably made of the same material as each other. This makes it easier to control the physical properties by using the width of the fiber bundle 3 as a control factor, so that the reinforcing fiber composite material 1 having the desired physical properties can be realized more reliably.

Examples of the fibers used as the first fiber bundle 31 and the second fiber bundle 32 include glass fiber, carbon fiber, aluminum fiber, copper fiber, stainless steel fiber, brass fiber, titanium fiber, steel fiber, and phosphorus bronze fiber. Metallic fiber, cotton fiber, silk fiber, natural fiber such as wood fiber, ceramic fiber such as alumina fiber, total aromatic polyamide (aramid), total aromatic polyester, total aromatic polyesteramide, total aromatic polyether , Total aromatic polycarbonate, total aromatic polyazomethin, polyphenylene sulfide (PPS), poly (para-phenylene benzobisthiazole) (PBZT), polybenzoimidazole (PBI), polyether ether ketone (PEEK), polyamideimide (PAI) ), Polytetrafluoroethylene (PTFE), synthetic fibers such as poly (para-phenylene-2,6-benzobisoxazole) (PBO), etc., and those containing at least one of these include Used.

The first fiber bundle 31 and the second fiber bundle 32 are not limited to those composed of only one type of single fiber, and may be formed by bundling a plurality of types of single fibers.

The first fiber bundle 31 may be a fiber bundle containing organic fibers or a fiber bundle containing inorganic fibers as long as it has a width within the above-mentioned range. In other words, the single fiber contained in the first fiber bundle 31 may be an organic fiber or an inorganic fiber.

Similarly, the second fiber bundle 32 may be a fiber bundle containing organic fibers or a fiber bundle containing inorganic fibers as long as it has a width within the above-mentioned range. In other words, the single fiber contained in the second fiber bundle 32 may be an organic fiber or an inorganic fiber.

Of these, by using organic fibers as the first fiber bundle 31 and the second fiber bundle 32, the weight of the reinforcing fiber composite material 1 can be reduced. In addition, since some organic fibers have extremely high mechanical strength, it is possible to achieve both weight reduction and high strength by selecting them. Examples of the organic fiber include natural fiber and synthetic fiber.

On the other hand, by using inorganic fibers as the first fiber bundle 31 and the second fiber bundle 32, the strength of the reinforcing fiber composite material 1 can be increased. That is, since the inorganic fiber generally has high mechanical strength such as tensile strength, it tends to contribute to increasing the strength of the reinforcing fiber composite material 1. Further, since the inorganic fiber has features such as thermal conductivity, conductivity, and low expansion property, these physical characteristics can be added to the reinforcing fiber composite material 1. Therefore, it is possible to realize the reinforcing fiber composite material 1 having various added values. Examples of the inorganic fiber include glass fiber, carbon fiber, metal fiber, ceramic fiber and the like.

In addition to the fiber bundle 3, the reinforcing fiber composite material 1 may contain a single fiber in which the fiber bundle 3 is completely opened or other single fiber.

The average length of the first fiber bundle 31 and the second fiber bundle 32 is not particularly limited, but is preferably 5 mm or more, more preferably 7 mm or more, still more preferably 10 mm or more. .. By setting the average length of the first fiber bundle 31 and the second fiber bundle 32 within the above range, the mechanical properties of the reinforcing fiber composite material 1 can be sufficiently enhanced. In particular, even when the mechanical properties of the resin 2 are relatively low, it can be sufficiently supplemented by the first fiber bundle 31 and the second fiber bundle 32. As a result, the reinforcing fiber composite material 1 having particularly good mechanical properties can be obtained.

The upper limit of the average length of the first fiber bundle 31 and the second fiber bundle 32 is not particularly limited, but is preferably 100 mm or less, more preferably 50 mm or less, for example. As a result, when the first fiber bundle 31 and the second fiber bundle 32 are dispersed in the dispersion medium in producing the reinforcing fiber composite material 1, the dispersibility thereof becomes good. As a result, the reinforcing fiber composite material 1 having excellent mechanical properties is finally obtained.

The average length of the first fiber bundle 31 and the second fiber bundle 32 means that 100 or more first fiber bundles 31 and the second fiber bundle 32 are taken out by dissolving the resin 2 of the reinforcing fiber composite material 1 or the like. After that, the lengths are measured and averaged.

Further, the first fiber bundle 31 and the second fiber bundle 32 may each contain long fibers having a length of 20 mm or more. By including such very long fibers as the first fiber bundle 31 and the second fiber bundle 32, the reinforcing fiber composite material 1 is imparted with extremely high mechanical properties. Therefore, for example, even when a resin 2 having low mechanical properties is used, it can be sufficiently supplemented by the first fiber bundle 31 and the second fiber bundle 32. As a result, it becomes possible to select a resin 2 specialized for the desired characteristics, for example, a resin 2 having slightly inferior mechanical properties but excellent flame retardancy, and is a reinforcing fiber composite material having various properties. 1 is obtained.

The length of the long fibers is preferably 25 mm or more, more preferably 30 mm or more.

If the length of the long fibers is less than the above range, the mechanical properties expected of the conventional composite molded body cannot be exceeded, and the mechanical properties are excellent enough to replace, for example, metal parts. There is a risk that the purpose of adding long fibers, such as acquisition, will not be achieved.

The upper limit of the length of the long fiber is not particularly limited, but is preferably 200 mm or less, and more preferably 150 mm or less. As a result, when the first fiber bundle 31 and the second fiber bundle 32 are dispersed in the dispersion medium in producing the reinforcing fiber composite material 1, the dispersibility thereof becomes good. As a result, the reinforcing fiber composite material 1 having excellent mechanical properties is finally obtained.

Such long fibers may be contained in the first fiber bundle 31 and the second fiber bundle 32 as much as possible, but are contained in a ratio of 10% or more of the first fiber bundle 31 and the second fiber bundle 32. It is preferable that the fiber is contained in a proportion of 20 to 90%. As a result, the above-mentioned effects brought about by the long fibers are more reliably exhibited. That is, since the long fibers are predominantly present, the influence of the long fibers is also predominant in the mechanical properties of the reinforcing fiber composite material 1. As a result, it is possible to realize the reinforcing fiber composite material 1 having particularly high mechanical properties.

The content of the long fibers was measured by dissolving the resin 2 of the reinforcing fiber composite material 1 and taking out 100 or more first fiber bundles 31 and second fiber bundles 32, and then measuring their lengths, respectively. , It is obtained as a ratio of the number of the first fiber bundle 31 and the second fiber bundle 32 having a length of 20 mm or more.

The average width of the fiber bundle 3 is not particularly limited, but is preferably about 1 to 30 mm, more preferably about 3 to 20 mm. By setting the average width of the fiber bundle 3 within the above range, the dispersibility of the fiber bundle 3 is improved while increasing the mechanical strength of the entire reinforcing fiber composite material 1, and when the reinforcing fiber composite material 1 is manufactured. The formability of the material can be improved.

The average width of the fiber bundle 3 is a value obtained by measuring and averaging the maximum widths of 100 or more fiber bundles 3 after taking out 100 or more fiber bundles 3 by dissolving the resin 2 of the reinforcing fiber composite material 1 or the like. To say.

The length ratio (length / width) to the width of the first fiber bundle 31 and the second fiber bundle 32 is not particularly limited, but is preferably 5 or more, and more preferably 10 or more. As a result, the first fiber bundle 31 and the second fiber bundle 32 more reliably exert the above-mentioned effects.

The average diameter of the single fibers contained in the first fiber bundle 31 and the second fiber bundle 32 is not particularly limited, but is preferably about 1 to 100 μm, and more preferably about 5 to 80 μm. By setting the average diameter of the single fiber within the above range, it is possible to improve the mechanical properties of the reinforcing fiber composite material 1 and to improve the moldability when manufacturing the reinforcing fiber composite material 1.

The average diameter of the single fibers refers to the average value obtained by measuring the diameters of 100 or more single fibers after taking out 100 or more single fibers by dissolving the resin 2 of the reinforcing fiber composite material 1, etc.

Further, the first fiber bundle 31 and the second fiber bundle 32 are subjected to surface treatment such as coupling agent treatment, surfactant treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, plasma irradiation treatment and the like, if necessary. May be.

Among these, examples of the coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, and γ-aminopropyltri. Amino groups such as methoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldiethoxysilane Examples thereof include contained alkoxysilanes and their hydrolyzates, and those containing at least one of these are used.

The total content of the first fiber bundle 31 and the content of the second fiber bundle 32 in the reinforcing fiber composite material 1 is not particularly limited, but is preferably about 1 to 300% by volume of the resin 2, preferably 5 to 150. It is more preferably about 10% by volume, and even more preferably about 10 to 120% by volume. By setting the total of the content of the first fiber bundle 31 and the content of the second fiber bundle 32 within the above range, the quantitative balance between the resin 2 and the first fiber bundle 31 and the second fiber bundle 32 can be achieved. Since it is optimized, the mechanical properties of the reinforcing fiber composite material 1 can be particularly enhanced. That is, when the total content of the first fiber bundle 31 and the content of the second fiber bundle 32 is less than the lower limit, the first fiber bundle 31 and the second fiber bundle 32 are relatively insufficient, so that the resin 2 is used. The mechanical properties of the reinforcing fiber composite material 1 may deteriorate depending on the composition of the above, the lengths of the first fiber bundle 31 and the second fiber bundle 32, the constituent materials, and the like. On the other hand, when the first fiber bundle 31 and the second fiber bundle 32 exceed the upper limit, the content of the resin 2 is relatively insufficient, so that the composition of the resin 2 and the first fiber bundle 31 and the second fiber bundle 32 Depending on the length, constituent materials, etc., the mechanical properties of the reinforcing fiber composite material 1 may deteriorate.

The shapes of the first fiber bundle 31 and the second fiber bundle 32 shown in FIG. 1 are examples, and are not limited to the linear shape as shown in the drawing, and may be any shape, for example, a spiral shape, a meandering shape, or the like. May be good.

Further, the first fiber bundle 31 and the second fiber bundle 32 may be oriented in any direction in the reinforcing fiber composite material 1, but are preferably oriented so as to be parallel to the surface. This makes it possible to increase the toughness of the surface of the reinforcing fiber composite material 1 in the tensile direction. In addition, the wear resistance and hardness of the surface of the reinforcing fiber composite material 1 are also increased.

The abundance ratio of the first fiber bundle 31 and the second fiber bundle 32 is appropriately set according to the physical properties of the target reinforcing fiber composite material 1, but the content of the first fiber bundle 31 is 100 parts by volume. The content of the second fiber bundle 32 is preferably 10 to 1000 parts by volume, more preferably 20 to 500 parts by volume. As a result, only one of the first fiber bundle 31 and the second fiber bundle 32 is not excessively present, but is present in a well-balanced manner. Therefore, it is possible to suppress the occurrence of deformation such as warpage.

In addition to the first fiber bundle 31 and the second fiber bundle 32, another fiber (third fiber bundle) having an arbitrary degree of opening may be added to the reinforcing fiber composite material 1.

(pulp)
The reinforcing fiber composite material 1 may contain pulp, if necessary. Pulp is a fiber material having a fibril structure, and is different from the first fiber bundle 31 and the second fiber bundle 32. Pulp can be obtained, for example, by mechanically or chemically fibrilizing the fibrous material.

Further, when the reinforcing fiber composite material 1 is manufactured by the papermaking method, the cohesiveness of the material can be enhanced, so that the papermaking can be performed efficiently and stably.

Examples of the pulp include linter pulp, cellulose fiber such as wood pulp, natural fiber such as kenaf, jute and bamboo, para-type total aromatic polyamide fiber (aramid fiber) and its copolymer, aromatic polyester fiber, and the like. Examples thereof include polybenzazole fibers, meta-aramid fibers and their copolymers, acrylic fibers, acrylonitrile fibers, polyimide fibers, organic fibers such as polyamide fibers, and the like, and at least one of these is fibrillated. Used.

The pulp content in the reinforcing fiber composite material 1 is not particularly limited, but is preferably about 0.5 to 10% by mass, more preferably about 1 to 8% by mass, and 1). It is more preferably about 5 to 5% by mass. Thereby, the reinforcing fiber composite material 1 having better mechanical properties and thermal conductivity can be realized.

The average diameter of the pulp is preferably smaller than the average diameter of the single fibers contained in the first fiber bundle 31 and the second fiber bundle 32, and specifically, it is preferably about 0.01 to 2 μm.

The average length of the pulp is not particularly limited, but is preferably about 0.1 to 100 mm, more preferably about 0.5 to 10 mm.

The BET specific surface area is used as an index for fibrillation of pulp. BET specific surface area of the pulp is not particularly limited, and is preferably about 3~25m ² / g, and more preferably about 5 to 20 m ² / g. Thereby, while sufficiently ensuring the entanglement between the pulps or the pulp and the first fiber bundle 31 and the second fiber bundle 32, the papermaking stability can be achieved when the reinforcing fiber composite material 1 is manufactured by the papermaking method.

(Coagulant)
The reinforcing fiber composite material 1 may contain a flocculant, if necessary.

Examples of the flocculant include a cationic polymer flocculant, an anionic polymer flocculant, a nonionic polymer flocculant, an amphoteric polymer flocculant, and the like, and at least one of these is used.

More specifically, for example, cationic polyacrylamide, anionic polyacrylamide, Hoffmann polyacrylamide, mannic polyacrylamide, amphoteric copolymerized polyacrylamide, cationized starch, amphoteric starch, polyethylene oxide and the like can be mentioned.

The content of the flocculant in the reinforcing fiber composite material 1 is not particularly limited, but is preferably about 0.01 to 1.5% by mass, preferably about 0.05 to 1% by mass of the resin 2. Is more preferable, and more preferably about 0.1 to 0.5% by mass. As a result, when the reinforcing fiber composite material 1 is manufactured by, for example, a papermaking method, dehydration treatment and the like can be easily and stably performed, and finally the reinforcing fiber composite material 1 having excellent mechanical properties can be obtained.

(Other additives)
The reinforcing fiber composite material 1 may contain other additives, if necessary.

Examples of such additives include fillers, metal powders, antioxidants, ultraviolet absorbers, flame retardants, mold release agents, plasticizers, curing catalysts, curing aids, pigments, lightfasteners, antistatic agents, and antibacterial agents. , Conductive agents, dispersants and the like, and at least one of these is used.

Among these, examples of the curing aid include imidazole compounds, tertiary amine compounds, organic phosphorus compounds, magnesium oxide and the like.

Further, as the filler, for example, an inorganic filler, an organic filler and the like are used. Specific constituent materials include, for example, oxides such as titanium oxide, alumina, silica, zirconia, magnesium oxide and calcium oxide, nitrides such as boron nitride, aluminum hydroxide and silicon nitride, barium sulfate and sulfuric acid. Iron, sulfides such as copper sulfate, aluminum hydroxide, hydroxides such as magnesium hydroxide, kaolinite, talc, natural mica, minerals such as synthetic mica, carbides such as silicon carbide, etc. Can be mentioned. Further, these powders may be subjected to a surface treatment such as a coupling agent treatment.

Further, as the filler, metal powder, glass beads, milled carbon, graphite, polyvinyl butyral, wood powder and the like may be used.

Examples of the release agent include zinc stearate, calcium stearate, magnesium stearate and the like.

Examples of the coupling agent include an epoxy silane coupling agent, a cationic silane coupling agent, an aminosilane coupling agent, and a titanate-based coupling agent.

Examples of the flame retardant include metal hydroxides such as aluminum hydroxide and magnesium hydroxide, antimony compounds, halogen compounds, phosphorus compounds, nitrogen compounds, and boron compounds.

(Vacancy)
Further, the reinforcing fiber composite material 1 may include pores inside. As a result, the density (specific gravity) of the reinforcing fiber composite material 1 can be reduced, and the weight can be reduced.

The pores refer to the spaces contained in the reinforcing fiber composite material 1. The pores may be spaces (closed cells) in which one or more of them are connected to each other and are isolated from the outside of the system (surrounded by resin 2 or the like), and communicate with the outside of the system. It may be a space (open air bubbles).

Of these, although not particularly limited, it is preferable that the number of closed cells is larger than that of open cells. As a result, the mechanical properties of the reinforcing fiber composite material 1 are less likely to deteriorate even if pores are included. This is because the closed cells are hard to be crushed, and the mechanical strength of the reinforcing fiber composite material 1 is hard to be lowered accordingly.

The fact that the number of closed cells is larger than that of open cells means that the total area occupied by the closed cells is larger than the total area occupied by the open cells when the cross section of the reinforcing fiber composite material 1 is enlarged and observed.

When the reinforcing fiber composite material 1 contains closed cells as pores, the average diameter of the pores is not particularly limited, but is preferably about 2 to 300 μm, more preferably about 5 to 200 μm. As a result, it is possible to achieve both the weight reduction of the reinforcing fiber composite material 1 due to the pores and the suppression of the deterioration of the mechanical properties of the reinforcing fiber composite material 1 due to the pores. That is, when the average diameter of the pores is less than the lower limit, it may be difficult to reduce the weight of the reinforcing fiber composite material 1 depending on the porosity. On the other hand, when the average diameter of the pores exceeds the upper limit value, the pores tend to be the starting points of refraction, cracks, etc. depending on the porosity, so that the mechanical properties of the reinforcing fiber composite material 1 may deteriorate. be.

The average diameter of the holes is obtained as the diameter of the circle (diameter equivalent to the circle) when a circle having the same area as the area of the holes is assumed from the cross section of the reinforcing fiber composite material 1.

The porosity of the reinforcing fiber composite material 1 is not particularly limited, but is preferably about 10 to 90%, more preferably about 15 to 87.5%, and more preferably about 20 to 85%. More preferred. By setting the porosity within the above range, it is possible to achieve both the weight reduction of the reinforcing fiber composite material 1 and the mechanical properties in a well-balanced manner. That is, when the porosity is less than the lower limit, the weight reduction of the reinforcing fiber composite material 1 is insufficient depending on the composition of the resin 2, the lengths of the first fiber bundle 31 and the second fiber bundle 32, the constituent materials, and the like. May become. On the other hand, when the porosity exceeds the upper limit, the mechanical properties of the reinforcing fiber composite material 1 deteriorate depending on the composition of the resin 2, the lengths of the first fiber bundle 31 and the second fiber bundle 32, the constituent materials, and the like. There is a risk of

When the pores contain closed cells, the heat insulating property of the reinforcing fiber composite material 1 is improved. As a result, the thermal conductivity of the reinforcing fiber composite material 1 is lowered, so that the flame retardancy can be improved.

The pore ratio of the reinforcing fiber composite material 1 is obtained, for example, as a ratio of the area occupied by the pores (area ratio of the pores) in the cross-sectional area of the reinforcing fiber composite material 1.

Further, when the reinforcing fiber composite material 1 contains pores, the pores can also be unevenly distributed as a result of uneven distribution of the second fiber bundle 32 as described above. As a result, for example, on the first surface 11, the second fiber bundle 32 is unevenly distributed to obtain high hardness, while on the second surface 12 side, the reinforcing fiber composite is provided with heat insulating properties by containing many pores. Material 1 is obtained. According to such a reinforcing fiber composite material 1, both surface hardness, heat insulating property, and weight reduction can be achieved at the same time, and the added value can be further improved.

(Manufacturing method and application)
The reinforcing fiber composite material 1 may be manufactured by any method, but it is preferably a papermaking body as described later. The papermaking body is a structure in which fibers are dispersed, which is obtained by making a dispersion liquid containing fibers. According to such a papermaking body, since relatively long fibers are entangled with each other, it is easy to increase the mechanical strength. Therefore, even when the fiber content is suppressed or the porosity is increased, the reinforcing fiber composite material 1 having high mechanical strength can be obtained.

The structure containing fibers is also known to be other than the abstracted body (for example, an injection molded body of a composition containing a fiber filler, an extruded body, etc.), but a structure in which particularly long fibers are uniformly dispersed. The abstract is preferably used from the viewpoint that it is easy to obtain.

The reinforcing fiber composite material 1 has been described above, but the reinforcing fiber composite material 1 can be applied to any structure. As an example, an interior material for transportation equipment can be exemplified. Specifically, cabin ceiling panel, cabin interior panel, cabin floor, cockpit ceiling panel, cockpit interior panel, cockpit floor, baggage locker wall, storage locker wall, door lining, window cover, captain's seat, co-pilot Seats, flight attendant seats, various seats such as passenger seats, various aircraft interior materials such as dressing room interior materials, automobile interior materials, ship interior materials, railway interior materials, spacecraft interior materials, etc. Can be mentioned. All of such interior materials for transportation equipment are required to be lightweight and have high mechanical strength from the viewpoint of safety and transportation efficiency. Therefore, the reinforcing fiber composite material 1 is particularly preferably used.

For these interior materials, for example, the inside of the transportation equipment (cabin side) requires sufficient surface hardness from the viewpoint of wear resistance and the like, while the outside may not necessarily require such wear resistance. .. Therefore, by using a member having different surface hardness between the first surface 11 and the second surface 12, such as the reinforcing fiber composite material 1, the features of light weight and high mechanical strength are not impaired. The surface hardness on the first surface 11 side can be increased to ensure wear resistance. As a result, it is possible to achieve both weight reduction and wear resistance. In other words, the surface hardness of the first surface 11 is partially increased by biasing the wide first fiber bundle 31 toward the first surface 11 side without increasing the amount of fibers in the entire reinforcing fiber composite material 1. Can be enhanced. Therefore, the hardness of the surface specialized for the first surface 11 can be increased without impairing the weight reduction of the entire surface.

The reinforcing fiber composite material 1 may be applied to all of these interior materials for transportation equipment, or may be applied to only a part of them.

Further, the reinforcing fiber composite material 1 can be applied to, for example, a mounting substrate on which different electronic elements are mounted on the first surface 11 and the second surface 12. In such a mounting board, for example, an electronic element having a large calorific value is mounted on the first surface 11 side, while an electronic element required to have high insulation between terminals is mounted on the second surface 12 side. It is especially useful in such cases.

(Physical characteristics)
Here, the bending strength of the reinforcing fiber composite material 1 is not particularly limited, but is preferably about 50 to 400 MPa, more preferably about 70 to 350 MPa, and even more preferably about 100 to 300 MPa. As a result, the reinforcing fiber composite material 1 having sufficiently high mechanical properties can be obtained.

The bending strength of the reinforcing fiber composite material 1 is measured at room temperature (25 ° C.) according to the test method specified in ISO178: 2001.

The specific strength of the reinforcing fiber composite material 1 is 50 to 400 MPa · (g / cm ³ ) ^-1 . As a result, the reinforced fiber composite material 1 in which both weight reduction and improvement of mechanical properties are achieved can be obtained. If the specific strength is lower than the lower limit, it can be said that the bending strength is small for the heavy weight. Therefore, structural materials in fields where both weight reduction and high mechanical properties are required, such as interior materials for transportation equipment. May be inappropriate. On the other hand, if the specific strength exceeds the upper limit, it can be said that the bending strength is large for its light weight, but the impact resistance is lowered depending on the balance with other physical properties, and variations due to manufacturing conditions are likely to occur. It may be difficult to increase the manufacturing yield.

Also, specific strength of the reinforcing fiber composite material 1, more preferably from 100~390MPa · ^{(g /} cm ³⁾ about ^{-1, 150~380MPa · (g / cm} 3) is about ^-1 and even more preferable.

The specific strength of the reinforcing fiber composite material 1 is obtained by dividing the bending strength (unit: MPa) by the density (unit: g / cm ^3).

Further, specific modulus of the reinforcing fiber composite material 1 is not particularly limited, but is preferably 2~30GPa · ^{(g /} cm ³⁾ about ^{-1, 3~25GPa · (g / cm} 3) about ^-1 It is more preferable that it is about 4 to 20 GPa · (g / cm ³ ) ^-1. As a result, the reinforced fiber composite material 1 in which both weight reduction and improvement of mechanical properties are achieved can be obtained.

The specific elastic modulus of the reinforcing fiber composite material 1 is obtained by dividing the flexural modulus (unit: GPa) by the density (unit: g / cm ^3). The flexural modulus is measured at room temperature (25 ° C.) according to the test method specified in ISO178: 2001.

The density of the reinforcing fiber composite material 1 is not particularly limited, but is preferably 0.05~1.6g / cm ³ or so, more preferably from 0.1~1.55g / cm ³ approximately , 0.2 to 1.5 g / cm ³ is more preferable. As a result, the reinforced fiber composite material 1 having both weight reduction and improvement of mechanical properties can be obtained.

The density is measured according to the test method specified as Method A in JIS K 7112: 1999.

<Manufacturing method of reinforcing fiber composite material>
Next, an embodiment of the method for producing a reinforcing fiber composite material of the present invention will be described.

2 to 6 are diagrams for explaining an example (papermaking method) of a method for producing the reinforcing fiber composite material shown in FIG. 1, respectively.

The method for producing the reinforcing fiber composite material 1 includes a step of preparing a dispersion liquid 6 containing the resin 2 and the first fiber bundle 31 (highly spread fiber bundle) and the second fiber bundle 32 ( lowly opened fiber bundle). At least a part of the resin 2 is melted by the step of making the element 10 from the dispersion 6 while precipitating the second fiber bundle 32 in the dispersion 6 and the pressure molding while heating the element 10. It has a step of obtaining a reinforcing fiber composite material 1 (an abstract molded body). Hereinafter, each step will be described in sequence.

[1] First, as shown in FIG. 2, a dispersion liquid 6 containing the resin 2, the first fiber bundle 31 and the second fiber bundle 32, and the dispersion medium 5 for dispersing them is prepared. The prepared dispersion 6 is sufficiently stirred and mixed. If necessary, the above-mentioned flocculant, pulp, other additives, and the like may be added to the dispersion liquid 6.

The shape of the resin 2 in this step is not particularly limited, and may be, for example, in the form of particles (powder) or fibrous such as substantially spherical particles and thin film particles. Thereby, in the papermaking described later, the resin 2 can be made together with the first fiber bundle 31 and the second fiber bundle 32. As a result, the resin 2 can be entangled with the first fiber bundle 31 and the second fiber bundle 32, and a basic body 10 capable of producing a strong reinforcing fiber composite material 1 can be obtained.

When the resin 2 contains a thermosetting resin, the thermosetting resin is preferably in a semi-cured state. The semi-curable thermosetting resin is formed into a desired shape by heating and pressurizing after manufacturing the element body 10, and is cured. As a result, the reinforcing fiber composite material 1 that makes the best use of the characteristics of the thermosetting resin can be obtained.

On the other hand, as the first fiber bundle 31 and the second fiber bundle 32, for example, fibers having a melting point higher than that of the resin 2 are used. By using such a first fiber bundle 31 and a second fiber bundle 32, only the resin 2 can be selectively melted when the element 10 is pressure-molded while being heated in the step described later. As a result, the resin 2 can be melted and dispersed around the first fiber bundle 31 and the second fiber bundle 32, and a strong reinforcing fiber composite material 1 can be obtained.

The melting points of the first fiber bundle 31 and the second fiber bundle 32 may be higher than the melting point of the resin 2, but the difference is preferably 10 ° C. or higher, and more preferably 50 ° C. or higher.

Here, the first fiber bundle 31 and the second fiber bundle 32 may be manufactured by subjecting the fiber bundles as raw materials to a fiber opening treatment and having different fiber opening rates. That is, the defibration rate corresponds to the ratio of the number of single fibers separated from the fiber bundle in the defibration treatment of unraveling the fiber bundle as a raw material and spreading it in a strip shape, for example, but the defibration rate is different. Therefore, the width of the fiber bundle 3 after the fiber opening treatment can be made different. Therefore, the first fiber bundle 31 and the second fiber bundle 32 can be produced from the same raw material, respectively. In other words, the width of the fiber bundle 3 can be changed and the content of the first fiber bundle 31 and the second fiber bundle 32 in the fiber bundle 3 can be adjusted by changing the processing amount in the fiber opening treatment.

As a result of such opening process, it can be a high spreading fiber bundle enhanced open繊率to the extent that leads width at least five times the average diameter of single fiber and the first fiber bundle 31, a width of a single the low opening fiber bundles with suppressed to the extent that remains below 5 times open繊率of the average diameter of the fiber may be a second fiber bundle 32.

The fiber opening treatment is not particularly limited, and examples thereof include a roll fiber opening method, an electrostatic method, and an air fiber opening method.

After the fiber opening treatment, the first fiber bundle 31 and the second fiber bundle 32 are obtained by cutting to a desired length.

Further, the dispersion medium 5 is difficult to dissolve the resin 2, the first fiber bundle 31, and the second fiber bundle 32, and volatilizes in the process of dispersing the resin 2, the first fiber bundle 31, and the second fiber bundle 32. Difficult ones are preferably used. Further, those that are easily desolvated are preferably used. From this point of view, the boiling point of the dispersion medium 5 is preferably about 50 to 200 ° C.

Examples of the dispersion medium 5 include water, ethanol, 1-propanol, 1-butanol, alcohols such as ethylene glycol, ketones such as acetone, methyl ethyl ketone, 2-heptanone and cyclohexanone, ethyl acetate, butyl acetate and acet. Examples thereof include esters such as methyl acetate and methyl acetoacetate, ethers such as tetrahydrofuran, isopropyl ether, dioxane and furfural, and at least one of these is used.

Of these, water is preferably used. Water is useful as a dispersion medium 5 because it is easily available, has a low environmental load, and is highly safe.

The content of the dispersion medium 5 in the dispersion liquid 6 is not particularly limited, but is preferably about 10% by mass or more and 1000% by mass or less with respect to the total amount of solid content.

Further, when forming pores in the reinforcing fiber composite material 1, microcapsules having thermal expansion may be added to the dispersion liquid 6. The microcapsules expand when heated and become vacancies.

The thermally expandable microcapsules are particles obtained by microencapsulating a volatile liquid foaming agent with a thermoplastic shell polymer having a gas barrier property. Such microcapsules function as a foaming agent by the following mechanism. When the microcapsules are heated, the outer shell of the capsule softens, and the liquid foaming agent contained in the capsule evaporates and the pressure increases. As a result, the capsule expands and hollow spherical particles are formed. Since the hollow spherical particles remain even after pressure molding, they contribute to the formation of pores as a result.

Examples of the liquid foaming agent include low boiling point hydrocarbons such as isopentane, isobutane, and isopropane.

Examples of the thermoplastic shell polymer include polyacrylonitrile, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-methylmethacrylate copolymer, vinylidene chloride-ethylmethacrylate, acrylonitrile-methylmethacrylate copolymer, acrylonitrile-ethylmethacrylate and the like. These may be used alone or in combination of two or more.

Examples of microcapsules include commercially available products such as Expancel (manufactured by Nippon Ferrite Co., Ltd.), Microsphere F50, Microsphere F60 (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.), and Advansel EM (manufactured by Sekisui Chemical Co., Ltd.). Can be used.

The amount of the microcapsules added is preferably about 0.05 to 10% by mass, more preferably about 0.1 to 5% by mass.

[2] Subsequently, the prime form 10 is made from the prepared dispersion liquid 6. As a result, a basic body 10 for manufacturing the reinforcing fiber composite material 1 is obtained (see FIG. 5).

Specifically, first, as shown in FIG. 3, a container 70 provided with a filter 71 on the bottom surface is prepared.

Next, the dispersion liquid 6 is supplied into the container 70. Then, the dispersion medium 5 in the dispersion liquid 6 is discharged to the outside from the bottom surface of the container 70 via the filter 71. As a result, the resin 2, which is the dispersoid in the dispersion liquid 6, and the first fiber bundle 31 and the second fiber bundle 32 remain on the filter 71 (papermaking). By drying this residue, the prime form 10 is obtained.

At this time, by appropriately selecting the shape of the filter 71, it is possible to manufacture the elemental body 10 having a desired shape.

Further, although the first fiber bundle 31 and the second fiber bundle 32 are dispersed in the dispersion liquid 6, the first fiber bundle 31 and the second fiber bundle 32 can be combined by adjusting the viscosity of the dispersion liquid 6. Differences in the degree of sedimentation can be provided. That is, the second fiber bundle 32 is settled before the first fiber bundle 31 by utilizing the difference in the settling speed based on the difference in the respective widths (difference in the degree of opening), so that the second fiber bundle 32 is settled in the dispersion liquid 6. The 1 fiber bundle 31 and the 2nd fiber bundle 32 can be unevenly distributed. As a result, the second fiber bundle 32 is unevenly distributed on the filter 71 side (lower side in FIG. 3), and the first fiber bundle 31 is unevenly distributed on the side opposite to the filter 71 side (upper side in FIG. 3). Is obtained (see FIG. 5).

By subjecting such an element 10 to a step described later, as described above, the area ratio occupied by the first fiber bundle 31 on the first surface 11 is occupied by the first fiber bundle 31 on the second surface 12. A reinforcing fiber composite material 1 having an area ratio larger than that of the area ratio can be obtained.

Since the difference in the degree of sedimentation increases as the time for allowing the dispersion liquid 6 to stand still increases, it is also controlled by adjusting the standing time. When adjusting the standing time, the time required for filtration of the dispersion liquid 6 can be changed by changing the opening of the filter 71 as necessary, and as a result, the standing time is adjusted. Can be done.

Then, for example, by reducing the viscosity of the dispersion liquid 6 or lengthening the standing time, the difference in the degree of sedimentation can be increased. On the other hand, the difference in the degree of sedimentation can be reduced by increasing the viscosity of the dispersion liquid 6 or shortening the standing time.

Further, the viscosity of the dispersion liquid 6 can be adjusted by appropriately setting the concentration of the above-mentioned flocculant (fixing agent). For example, the concentration of the flocculant added to the dispersion liquid 6 is preferably 50 to 1000 ppm by mass ratio, and more preferably 100 to 500 ppm. As a result, the viscosity of the dispersion liquid 6 is optimized, and the second fiber bundle 32 is formed by allowing the dispersion liquid 6 to stand while uniformly dispersing the first fiber bundle 31 and the second fiber bundle 32 in the dispersion liquid 6. It can be settled first.

If the concentration of the flocculant in the dispersion liquid 6 is lower than the lower limit, the viscosity of the dispersion liquid 6 becomes too low, so that the first fiber bundle 31 and the second fiber bundle 32 aggregate or the sedimentation speed is too fast. There is a risk that the uneven distribution of fibers will become too large. On the other hand, when the concentration of the flocculant in the dispersion liquid 6 exceeds the upper limit value, the viscosity of the dispersion liquid 6 becomes too high, so that a difference in settling speed occurs between the first fiber bundle 31 and the second fiber bundle 32. It becomes difficult and there is a risk that it will not be possible to form an uneven distribution state.

The elementary form 10 thus obtained may or may not contain the dispersion medium 5.

Further, after the formation of the element body 10, as necessary, the element form 10 is arranged between the press mold 72 and the press mold 73, and between the press mold 72 and the press mold 73. The element 10 is compressed by the cavity (not shown) formed. For example, by lowering the press die 72 as shown by the arrow P, the element 10 is compressed between the press die 72 and the press die 73. As a result, the dispersion medium 5 remaining in the element body 10 can be sufficiently discharged, and the element form 10 can be dried.
If necessary, it may be further dried with a dryer or the like.

Further, when a fibrous resin 2 is used, it is possible to obtain a prime form 10 having a particularly low apparent density. Such a prime body 10 enables the production of the reinforcing fiber composite material 1 having a low density by appropriately setting the conditions in the pressure molding described later. That is, a reinforcing fiber composite material 1 having been sufficiently reduced in weight can be obtained.

The average length of the fibrous resin 2 is not particularly limited, but is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 4 mm or more. By setting the average length of the fibrous resin 2 within the above range, the degree of entanglement between the fibrous resin 2 and the first fiber bundle 31 and the second fiber bundle 32 is further increased. As a result, the range of porosity that can be realized in the manufactured reinforcing fiber composite material 1 can be made wider.

The upper limit of the average length of the fibrous resin 2 is not particularly limited, but is preferably 100 mm or less, more preferably 50 mm or less, for example. As a result, when the fibrous resin 2 is dispersed in the dispersion medium 5 in the production of the reinforcing fiber composite material 1, the dispersibility thereof becomes good. As a result, the reinforcing fiber composite material 1 having excellent mechanical properties is finally obtained.

The average length of the fibrous resin 2 is an average value obtained by measuring the lengths of any 100 or more fibrous resins 2.

The average length of the fibrous resin 2 is preferably about 10 to 1000% of the average length of the first fiber bundle 31 and the second fiber bundle 32, and is preferably about 20 to 500%. More preferred. As a result, the degree of entanglement between the fibrous resin 2 and the first fiber bundle 31 and the second fiber bundle 32 becomes more remarkable, so that the shape-retaining property of the element 10 becomes better and wider. A basic body 10 capable of easily producing the reinforcing fiber composite material 1 having a porosity in the range can be obtained.

The average diameter of the fibrous resin 2 is not particularly limited, but is preferably about 1 to 100 μm, and more preferably about 5 to 80 μm. By setting the average diameter of the fibrous resin 2 within the above range, the fibrous resin 2 itself has a certain degree of mechanical strength, so that the fibrous resin 2 in the element 10 has a certain degree of mechanical strength. It becomes easy to maintain a uniformly dispersed state. As a result, the range of porosity that can be realized in the manufactured reinforcing fiber composite material 1 can be made wider.

The average diameter of the fibrous resin 2 is an average value obtained by measuring the diameters of any 100 or more fibrous resins 2.

Further, the ratio (length / diameter) of the length to the diameter of the fibrous resin 2 is preferably 10 or more, and more preferably 100 or more. As a result, the fibrous resin 2 more reliably exerts the above-mentioned effects.

Further, the element 10 may further contain a thermoplastic resin having a melting point of less than 200 ° C. (hereinafter referred to as “low melting point resin”). By including this low melting point resin, the shape-retaining property of the element body 10 can be further enhanced. That is, when the element 10 is heated at a temperature lower than the heating temperature in pressure molding (for example, drying), the low melting point resin is melted and the fibers such as the first fiber bundle 31 and the second fiber bundle 32 are made of resin. Bonds 2 to each other or between the fiber and the resin 2. This makes it easier for the elemental body 10 to maintain its shape. As a result, it becomes easy to obtain the desired porosity of the finally obtained reinforcing fiber composite material 1, and the dimensional accuracy and mechanical properties are less likely to deteriorate. In addition, since the element 10 is less likely to lose its shape, it becomes easier to grip the element 10 and the portability is improved. As a result, the work of packing and transporting the element body 10 can be performed more easily.

The shape of the low melting point resin before melting is not particularly limited, and may be in the form of particles (powder) such as substantially spherical particles or thin film particles, or may be in the form of fibers.

The content of the low melting point resin in the element 10 is not particularly limited, but is preferably about 0.5 to 30% by volume, more preferably about 1 to 20% by volume, and 2 to 10% by volume. It is more preferably about%. As a result, the effect of enhancing the shape-retaining property of the element 10 by adding the low melting point resin without impairing the above-mentioned effect is necessary and sufficiently secured.

The melting point of the low melting point resin is preferably about 10 to 250 ° C. lower than the melting point of the resin 2, and more preferably about 50 to 200 ° C. Due to such a difference in melting point, the low melting point resin is melted in a process such as drying, and is easily removed by thermal decomposition during pressure molding. Therefore, the function of the low melting point resin can be maximized. That is, in the elementary form 10, the low melting point resin works to maintain the shape, and in the reinforcing fiber composite material 1, it is possible to suppress the deterioration of the mechanical properties due to the presence of a large amount of the low melting point resin.

The total content of the first fiber bundle 31 and the content of the second fiber bundle 32 in the element 10 is not particularly limited, but is preferably about 20 to 300% by volume of the resin 2, preferably 30 to 150% by volume. It is more preferably about 40 to 90% by volume, and even more preferably about 40 to 90% by volume. By setting the contents of the first fiber bundle 31 and the second fiber bundle 32 within the above range, the quantitative balance between the resin 2 and the first fiber bundle 31 and the second fiber bundle 32 is optimized. It is possible to obtain the elemental body 10 capable of producing the reinforcing fiber composite material 1 capable of achieving a wider range of porosity while enhancing the shape retention of the elemental form 10.

[3] Next, the element 10 is pressure-molded while being heated. As a result, at least a part of the resin 2 in the element body 10 is melted, and the reinforcing fiber composite material 1 (artificial molded body) is obtained.

Specifically, as shown in FIG. 6, the element 10 is arranged between the mold 74 and the mold 75, and the element is formed by a cavity (not shown) formed between the mold 74 and the mold 75. The feature 10 is pressure molded.

For example, by lowering the mold 74 as shown by the arrow P, the element 10 is compressed between the mold 74 and the mold 75. At this time, since the element 10 is heated at the same time, at least a part of the resin 2 is melted and flows between the first fiber bundle 31 and the second fiber bundle 32, and functions as a binder for binding them. After that, the resin 2 is cured, so that the fibers are bound to each other by the resin 2. As a result, the reinforcing fiber composite material 1 can be obtained from the element body 10.

The heating temperature at this time is appropriately set according to the composition of the resin 2 and the like, but as an example, it is preferably about 150 to 350 ° C., more preferably about 160 to 300 ° C.

The heating time at this time is appropriately set according to the heating temperature, but is preferably about 1 to 180 minutes, more preferably about 5 to 60 minutes.

The pressing force at this time is appropriately set according to the heating temperature and the heating time, but is preferably about 0.05 to 80 MPa, more preferably about 0.1 to 60 MPa.

The porosity of the reinforcing fiber composite material 1 can be adjusted by appropriately changing the conditions in this step. For example, when the heating temperature is lowered, the heating time is shortened, or the pressing force is reduced, the reinforcing fiber composite material 1 having a relatively large porosity can be obtained. On the other hand, when the heating temperature is raised, the heating time is lengthened, or the pressing force is increased, the reinforcing fiber composite material 1 having a relatively small porosity can be obtained.

Although the method for producing the reinforcing fiber composite material and the reinforcing fiber composite material of the present invention has been described above based on the illustrated embodiments, the present invention is not limited thereto.

For example, the reinforcing fiber composite material of the present invention may have any element added to the above embodiment.

Further, the method for producing the reinforcing fiber composite material of the present invention may be one in which an arbitrary step is added to the above-described embodiment, or may be one in which the order of each step of the above-described embodiment is changed.

Next, specific examples of the present invention will be described.
1. 1. Production of Reinforced Fiber Composite Material (Example 1)
[1] First, the following raw materials were added to water, and the mixture was stirred with a disperser for 20 minutes. As a result, a dispersion having a solid content concentration of 0.6% by mass was obtained. The details and compounding ratio of each raw material are as shown in Table 1.

-Resol type phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., product number PR-51723)
・High open fiber carbon fiber (first fiber bundle, PAN-based carbon fiber)
・Low open fiber carbon fiber (second fiber bundle, PAN-based carbon fiber)
・ Aramid pulp (manufactured by DuPont, product number para-aramid pulp)

[2] Next, a flocculant (polyethylene oxide, molecular weight 1,000,000) previously dissolved in water was added to the obtained dispersion at a ratio of 0.2% by mass with respect to the above-mentioned solid content, and the solid content was added. Was aggregated.

[3] Next, the dispersion was filtered through a 30-mesh metal net (screen), and the agglomerates were dehydrated and pressed at a pressure of 3 MPa to remove water.
Next, the dehydrated agglomerates were dried at 70 ° C. for 3 hours to obtain an elementary form.

[4] Next, a prime body was placed in the cavity of the molding die.
Next, while heating the molding die, the element was pressure-molded to a thickness of 4 mm. At this time, the heating temperature was 180 ° C., the pressing force was 2 MPa, and the pressurizing time was 10 minutes.
From the above, a reinforcing fiber composite material was obtained.

[5] Next, the first surface and the second surface of the manufactured reinforcing fiber composite material (length 50 mm × width 50 mm) were observed with an optical microscope to obtain observation images. The second surface is the surface that was in contact with the metal net (screen) at the time of papermaking, and the first surface is the surface opposite to the second surface. Subsequently, the first fiber bundle and the second fiber bundle were specified in the observation image, and the area ratio of each was calculated.

Then, the area ratio of the high open繊率carbon fiber (first fiber bundle) occupies the first surface and A1, high open繊率carbon fiber (first fiber bundle) is the area ratio occupied by the second surface and A2 At that time, A1-A2 was calculated as an index showing how much the relatively wide carbon fibers are unevenly distributed.

Further, the area ratio occupied by the low- spreading carbon fiber (second fiber bundle) on the first surface is B1, and the area ratio occupied by the low- spreading carbon fiber (second fiber bundle) on the second surface is B2. At that time, B2-B1 was calculated as an index showing how much the carbon fibers having a relatively narrow width were unevenly distributed.

The observation range is the entire surface of the first surface and the entire surface of the second surface of the reinforcing fiber composite material (length 50 mm × width 50 mm), and each of the above area ratios is the area occupied by each fiber bundle in the length 50 mm × width 50 mm. It was calculated as a ratio of.

(Examples 2 to 8)
A reinforcing fiber composite material was obtained in the same manner as in Example 1 except that the production conditions of the reinforcing fiber composite material were changed as shown in Table 1.
The abbreviations in Table 1 have the following meanings.

PPS: Polyphenylene sulfide PEI: Polyetherimide SUS: Stainless steel (SUS316L)

(Comparative Examples 1 to 4)
A reinforcing fiber composite material was obtained in the same manner as in Example 1 except that the production conditions of the reinforcing fiber composite material were changed as shown in Table 1.

2. 2. Evaluation of Reinforced Fiber Composite 2.1 Evaluation of Difference in Electrical Properties The reinforcing fiber composite of each example and each comparative example conforms to the general thermosetting plastic test method specified in JIS K 6911: 1995. , The surface resistance of the first surface and the second surface were determined, respectively.

Next, the difference in surface resistance (resistance difference) of each surface was calculated, and the ratio of the resistance difference to the surface resistance of the first surface was calculated. Then, the obtained ratio was evaluated in light of the following evaluation criteria.

<Evaluation criteria for surface resistance>
⊚: Resistance difference is 10% or more of the surface resistance of the first surface ○: Resistance difference is 3% or more and less than 10% of the surface resistance of the first surface Δ: Resistance difference is 1 of the surface resistance of the first surface % Or more and less than 3% ×: The evaluation result that the resistance difference is less than 1% of the surface resistance of the first surface is shown in Table 1.

2.2 Evaluation of flexural modulus For the reinforcing fiber composites of each example and each comparative example, the flexural modulus was measured at 25 ° C. by a method according to ISO178: 2001.
Then, the measured flexural modulus was evaluated against the following evaluation criteria.

<Evaluation criteria for flexural modulus>
⊚: Bending elastic modulus is 5 GPa or more ○: Bending elastic modulus is 3 GPa or more and less than 5 GPa Δ: Bending elastic modulus is 1 GPa or more and less than 3 GPa ×: Bending elastic modulus is less than 1 GPa Evaluation results are shown in Table 1. show.

As is clear from Table 1, the reinforcing fiber composite material of each example showed a significant difference in electrical properties between the first surface and the second surface. On the other hand, mechanical properties such as flexural modulus were good. Therefore, according to the present invention, it is possible to realize a reinforcing fiber composite material having an added value that the physical properties of the first surface and the second surface are different while maintaining the advantage of the reinforcing fiber composite material having high mechanical properties. Can be done.

Although not shown in the table, in each of the reinforcing fiber composite materials of each example, a significant difference in wear resistance was observed between the first surface and the second surface.

1 Reinforced fiber composite material 2 Resin 3 Fiber bundle 5 Dispersion medium 6 Dispersion liquid 10 Elementary body 11 First surface 12 Second surface 31 First fiber bundle 32 Second fiber bundle 70 Container 71 Filter 72 Press mold 73 Press mold 74 Molding mold 75 Molding mold P arrow

Claims (6)

Ri Na bundled plurality of single fibers, a first fiber bundle Ru der 5 times or more the average diameter of the width monofilament,
A second fiber bundle in which a plurality of single fibers are bundled and the width is less than 5 times the average diameter of the single fibers.
With resin
The have including papermaking product,
The average length of the first fiber bundle and the second fiber bundle is 100 mm or less, and the average length is 100 mm or less.
Of the two surfaces on the front and back relationship with each other, the area ratio occupied by the first fiber bundle at one side and A1 [%], the area fraction of an Oite the first fiber bundles on the other surface A2 [ %], The reinforcing fiber composite material is characterized in that A1-A2 is 10 to 90%. The reinforcing fiber composite material according to claim 1, wherein the first fiber bundle and the second fiber bundle have an average length of 5 mm or more. The reinforcing fiber composite material according to claim 1 or 2, wherein the single fiber is an inorganic fiber or an organic fiber. The reinforcing fiber composite material according to any one of claims 1 to 3, wherein the resin is a thermosetting resin. When the area ratio occupied by the second fiber bundle on one surface is B1 [%] and the area ratio occupied by the second fiber bundle on the other surface is B2 [%], B2-B1 is 10 to 10 The reinforcing fiber composite material according to any one of claims 1 to 4, which is 90%. A first fiber bundle of more than five times the average diameter of width of monofilament, a step width of the second fiber bundles less than 5 times the average diameter of the single fiber, is dispersed in a dispersion medium to prepare a dispersion ,
A step of making an elementary form from the dispersion while precipitating the second fiber bundle in the dispersion.
A step of obtaining a manuscript molded body having two surfaces which are in a front-to-back relationship with each other by pressure molding while heating the element body.
Have a,
Of the two surfaces, when the area ratio occupied by the first fiber bundle on one surface is A1 [%] and the area ratio occupied by the first fiber bundle on the other surface is A2 [%], A1. -A method for producing a reinforcing fiber composite material, characterized in that A2 is 10 to 90%.

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