JP2018165337A - Composite molding and method for producing composite molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite molding having high mechanical strength, and a method that can efficiently produce the composite molding.SOLUTION: A composite molding 1 has a resin 2 and fibers 3. The fibers 3 include long fibers of 20 mm or more in length. The fibers 3 may further include short fibers of less than 20 mm in length. In the fibers 3, the proportion of the long fibers is preferably 50 mass% or more. The long fibers are preferably inorganic fibers. The resin 2 may include a thermoplastic resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a composite molded body and a method for producing the composite molded body.

  For example, structural materials used for airplanes and automobiles are required to be further reduced in weight. By reducing the weight, the fuel consumption of aircraft and automobiles can be reduced.

  As such a structural material, for example, a fiber reinforced resin obtained by mixing a reinforced fiber such as glass fiber and a resin such as polypropylene is known. In such a fiber reinforced resin, the fibers are reinforced by being entangled with each other in all three-dimensional directions.

However, in recent years, there is a strong demand for structural materials to further increase mechanical strength.
Therefore, it has been proposed to form a papermaking body (composite molded body) using longer fibers (for example, see Patent Document 1). Thereby, it is attempted to further increase the mechanical strength of the papermaking body.

JP-A-4-174793

  However, even if such a fiber is used, the present situation is that it does not sufficiently meet the market demand for increasing the mechanical strength.

  An object of the present invention is to provide a composite molded body having high mechanical strength and a method for producing a composite molded body capable of efficiently manufacturing such a composite molded body.

Such an object is achieved by the present inventions (1) to (6) below.
(1) including resin and fiber,
A composite molded body comprising long fibers having a length of 20 mm or more as the fibers.

  (2) The composite molded article according to (1), further including short fibers having a length of less than 20 mm as the fibers.

  (3) The composite molded body according to (1) or (2), wherein the ratio of the long fibers is 50% by mass or more of the fibers.

  (4) The composite molded body according to any one of (1) to (3), wherein the long fibers are inorganic fibers.

  (5) The composite molded body according to any one of (1) to (4), wherein the resin includes a thermoplastic resin.

(6) A method for producing the composite molded article according to any one of (1) to (5) above,
Preparing a dispersion containing the resin, the long fibers, and a fixing agent, wherein the concentration of the fixing agent is 50 to 1000 ppm by mass,
Paper making the dispersion to obtain an intermediate;
Obtaining the composite molded body by pressure-molding the intermediate; and
The manufacturing method of the composite molded object characterized by having.

According to the present invention, a composite molded body having high mechanical strength can be obtained.
Moreover, according to this invention, the said composite molded object can be manufactured efficiently.

It is a perspective view which shows embodiment of the composite molded object of this invention. It is a figure for demonstrating an example of the method of manufacturing the composite molded object shown in FIG. It is a figure for demonstrating an example of the method of manufacturing the composite molded object shown in FIG. It is a figure for demonstrating an example of the method of manufacturing the composite molded object shown in FIG. It is a figure for demonstrating an example of the method of manufacturing the composite molded object shown in FIG. It is a figure for demonstrating an example of the method of manufacturing the composite molded object shown in FIG.

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

<Composite molded body>
First, an embodiment of the composite molded body of the present invention will be described.
FIG. 1 is a perspective view showing an embodiment of a composite molded body of the present invention.

  The composite molded body 1 shown in FIG. 1 has a sheet shape, and the main surface has a rectangular shape in plan view. The composite molded body 1 includes a resin 2 and fibers 3, and the fibers 3 include long fibers having a length of 20 mm or more.

  According to such a composite molded body 1, a high mechanical strength can be obtained. Thereby, the composite molded object 1 useful as a structural material of the field | area where it is calculated | required to make light weight and high mechanical strength compatible, for example like the interior material for transport apparatuses is obtained. That is, the composite molded body 1 satisfies the high mechanical strength derived from the fibers 3 while receiving the benefit of weight reduction derived from the resin 2.

Hereinafter, the components constituting the composite molded body 1 will be described in detail.
(resin)
The resin 2 imparts moldability and shape retention to the composite molded body 1 or functions as a binder that binds the fibers 3 together. Therefore, the resin 2 is not particularly limited as long as it has such a function. For example, phenol resin, epoxy resin, bismaleimide resin, unsaturated polyester resin, melamine resin, thermosetting resin such as polyurethane, polyamide resin (for example, nylon), thermoplastic urethane resin, polyolefin Resin (eg, polyethylene, polypropylene, etc.), polycarbonate, polyester resin (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), polyacetal, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, fluororesin (eg, polytetrafluoroethylene, polyfluoride) Vinylidene, etc.), modified polyphenylene ether, polysulfone, polyethersulfone, polyarylate, polyamideimide, polyetherimide, thermoplastic polyimide Thermoplastic resins such as. In addition, the resin 2 may include at least one of these, or may include two or more.

  It is preferable that the resin 2 contains at least one of a phenol resin, an epoxy resin, and a bismaleimide resin. Thereby, the mechanical characteristics and heat resistance of the composite molded body 1 can be particularly enhanced.

  Examples of phenolic resins include phenol novolac resins, cresol novolac resins, bisphenol A novolac resins, novolac phenol resins such as arylalkylene type novolac resins, unmodified resole phenol resins, tung oil, linseed oil, and walnut oil. And resol type phenol resins such as modified oil-modified resol phenol resins.

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

  Although the weight average molecular weight of a phenol-type resin is not specifically limited, It is preferable that it is about 1000-15000. In addition, when the weight average molecular weight of a phenol-type resin is less than the said lower limit, there exists a possibility that the viscosity of the resin 2 may become low too much and the shaping | molding at the time of manufacture may become difficult. On the other hand, if the weight average molecular weight of the phenolic resin exceeds the upper limit, the viscosity of the resin 2 becomes too high and the moldability during production may be reduced.

  The weight average molecular weight of the phenolic 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 novolak type and cresol novolak type, brominated bisphenol A type and brominated type. Examples thereof include brominated epoxy resins such as phenol novolac type, biphenyl type epoxy resins, naphthalene type epoxy resins, and tris (hydroxyphenyl) methane type epoxy resins.

  Among these, bisphenol type epoxy resins and novolac type epoxy resins are preferably used from the viewpoints of high fluidity and moldability.

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

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

  The bismaleimide-based resin is not particularly limited as long as it is a resin having maleimide groups at both ends of the molecular chain, for example, those having a benzene ring are preferable, and those represented by the following general formula (1) are more preferable. Preferably 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。］

Wherein, R ¹ to R ⁴ represents a hydrocarbon group or a hydrogen atom of 1 to 4 carbon atoms which may have a substituent. R ⁵ represents a divalent organic group. ]

  However, the bismaleimide resin may have a maleimide group in addition to both ends of the molecular chain.

  Here, the organic group is a hydrocarbon group that may contain atoms other than carbon atoms, and examples of atoms other than carbon atoms include O, S, and N.

R ⁵ preferably has a main chain structure in which a methylene group, an aromatic ring, and an ether bond (—O—) are bonded in any order, and has at least one of a substituent and a side chain on the main chain. May be. The total number of methylene groups, aromatic rings and ether bonds contained in the main chain structure is 15 or less. Examples of the substituent or side chain include a hydrocarbon group having 3 or less carbon atoms, a maleimide group, and a phenylene group.

  Examples of bismaleimide-based resins include N, N ′-(4,4′-diphenylmethane) bismaleimide, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, and 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, m-phenylenebismaleimide, p-phenylenebismaleimide, 4-methyl-1,3-phenylenebismaleimide, N, N′-ethylenedimaleimide, N, N′-hexamethylene Examples thereof include dimaleimide.

A curing agent is used in combination with the resin 2 as necessary.
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 includes amine compounds such as aliphatic polyamines, aromatic polyamines, and diciamine diamide, alicyclic acid anhydrides, aromatic acid anhydrides. Such acid anhydrides, polyphenol compounds such as novolak type phenol resins, imidazole compounds, and the like are used.

  Among these, a novolak type phenol resin is preferably used from the viewpoints of handleability and environmental aspects. 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, as a curing agent, from the viewpoint that the heat resistance of the cured product is easily improved. A novolac type phenol resin is preferably used.

For example, when a bismaleimide resin is used as the resin 2, an imidazole compound is used as the curing agent.
In addition, as a hardening | curing agent, the 1 type (s) or 2 or more types of what was mentioned above are used.

  On the other hand, the resin 2 may contain a thermoplastic resin in particular. Thereby, the moldability of the composite molded body 1 can be particularly improved, and the composite molded body 1 with higher dimensional accuracy can be obtained.

  Furthermore, it is preferable that the resin 2 contains super engineering plastic among thermoplastic resins. Thereby, in addition to the effect which a thermoplastic resin brings, the effect of a high mechanical characteristic will be added. Examples of super engineering plastics include polysulfone, polyether sulfone, polyphenylene sulfide, polyether ether ketone, polyarylate, polyamide imide, polyether imide, polyether ether ketone, liquid crystal polymer, and fluororesin.

  Although melting | fusing point of the resin 2 is not specifically limited, It is preferable that it is 200-400 degreeC, It is more preferable that it is 210-390 degreeC, It is further more preferable that it is 260-380 degreeC. By using such a resin 2, the mechanical properties and heat resistance of the composite molded body 1 can be sufficiently enhanced. Thereby, when the composite molded body 1 is applied to, for example, an interior material for transportation equipment, an interior material excellent in flame retardancy is obtained.

  If the melting point of the resin 2 is lower than the lower limit, the mechanical properties and heat resistance of the resin 2 become insufficient. Therefore, depending on the configuration of the composite molded body 1, the mechanical strength of the composite molded body 1 at a high temperature is high. May decrease, or the flame retardancy based on heat resistance may decrease. 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 reduced accordingly.

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

  Further, when the resin 2 has no crystal melting point and has a glass transition temperature, the melting point of the resin 2 in the present invention includes the glass transition temperature. This glass transition temperature can also be measured by the differential scanning calorimeter.

  Furthermore, 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 resistance temperature of the cured product of the thermosetting resin. This heat-resistant temperature is a deflection temperature under load defined in the general test method for thermoplastics of JIS K 6911: 1995.

(fiber)
The fibers 3 improve the mechanical properties of the composite molded body 1 or increase the thermal conductivity.

  As such a fiber 3, what was obtained by cut | disconnecting a fiber yarn or a long fiber bundle to predetermined length is used, for example.

  The fiber 3 includes a long fiber having a length of 20 mm or more. By including such a very long fiber 3, the composite molded body 1 has extremely excellent mechanical properties. For this reason, even if, for example, a resin 2 having a low mechanical property is used, it can be sufficiently supplemented by the fibers 3. As a result, it is possible to select a resin 2 that is specialized in the desired properties, for example, a material that is somewhat inferior in mechanical properties but excellent in flame retardancy, and a composite molded body 1 having various properties. Is obtained.

  Further, the length of the long fiber is preferably 25 mm or more, and more preferably 30 mm or more.

  When the length of the long fiber is less than the above range, it cannot exceed the range of mechanical properties expected for the conventional composite molded body, for example, excellent mechanical properties that can replace metal parts, etc. Cannot be acquired. For this reason, the manufacturing cost of the composite molded object 1 becomes high instead of mechanical characteristics by the complexity of the manufacturing process by using a long fiber, etc.

  In addition, although the upper limit of the length of a long fiber is not specifically limited, It is preferable that it is 200 mm or less, and it is more preferable that it is 150 mm or less. Thereby, when manufacturing the composite molded object 1, when disperse | distributing the fiber 3 to a dispersion medium, the dispersibility becomes favorable. As a result, a molded body having a homogeneous structure can be obtained, so that a composite molded body 1 having excellent mechanical properties can be finally obtained.

  Such a long fiber may be contained in the fiber 3 as much as possible, but it is preferably contained in the fiber 3 in a proportion of 50% by mass or more, and contained in a proportion of 60% by mass or more. It is more preferable that it is contained in a proportion of 70% by mass or more. As a result, the above-described effects brought about by the long fibers are more reliably expressed. That is, since the long fibers are dominantly present, the influence of the long fibers is also dominant in the mechanical characteristics of the composite molded body 1. As a result, the composite molded body 1 having particularly high mechanical properties can be realized.

  In addition, the content rate of a long fiber measures the length of each fiber 3 after taking out 100 or more fibers 3 by melt | dissolving the resin 2 of the composite molded object 1, etc., and length is 20 mm or more. It is determined as a ratio of the number of fibers 3.

  On the other hand, all of the fibers 3 may be long fibers, but may include fibers whose length does not reach the long fibers, that is, short fibers whose length is less than 20 mm. By including such short fibers, the impact resistance of the composite molded body 1 can be enhanced. That is, if the ratio of the long fibers becomes too high, depending on the content ratio of the fibers 3 and the composition of the resin 2, the impact resistance of the composite molded body 1 may be reduced. Inclusion of such problems can be suppressed.

  In this case, the content of the short fiber is not particularly limited, but is preferably less than the long fiber, more preferably about 0.1 to 90% by mass of the long fiber, and about 0.5 to 80% by mass. More preferably. Thereby, while the above-mentioned effect brought about by the long fiber becomes dominant, the effect brought about by the short fiber can be expressed simultaneously. That is, it is possible to realize the composite molded body 1 having excellent mechanical strength and impact resistance and toughness.

  In addition, the content rate of a short fiber measures the length of each fiber 3 after taking out 100 or more fibers 3 by melt | dissolving the resin 2 of the composite molded object 1, etc., and length is less than 20 mm. It is determined as a ratio of the number of fibers 3.

  Further, the average length of the fibers 3 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 fibers 3 within the above range, the mechanical properties of the composite molded body 1 can be sufficiently enhanced. In particular, even when the mechanical properties of the resin 2 are relatively low, the fibers 3 can sufficiently supplement it. As a result, a composite molded body 1 having particularly good mechanical properties can be obtained.

  In addition, although the upper limit of the average length of the fiber 3 is not specifically limited, For example, it is preferable that it is 100 mm or less, and it is more preferable that it is 50 mm or less. Thereby, when manufacturing the composite molded object 1, when disperse | distributing the fiber 3 to a dispersion medium, the dispersibility becomes favorable. As a result, a molded body having a homogeneous structure can be obtained, so that a composite molded body 1 having excellent mechanical properties can be finally obtained.

  The average length of the fibers 3 is a value obtained by measuring and averaging the lengths of any 100 or more fibers 3 taken out by dissolving the resin 2 of the composite molded body 1. .

  The average diameter of the fiber 3 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 fibers 3 within the above range, it is possible to improve the moldability when manufacturing the composite molded body 1 while enhancing the mechanical properties of the composite molded body 1.

  The average diameter of the fibers 3 means a value obtained by measuring and averaging the diameters of any 100 or more fibers 3 taken out by dissolving the resin 2 of the composite molded body 1.

  Further, the ratio of the length to the diameter of the fiber 3 (length / diameter) is preferably 10 or more, and more preferably 100 or more. Thereby, the fiber 3 exhibits the above effects more reliably.

  Examples of such fibers 3 include glass fibers, carbon fibers, aluminum fibers, copper fibers, stainless steel fibers, brass fibers, titanium fibers, steel fibers, phosphor bronze fibers, metal fibers, cotton fibers, silk fibers, Natural fiber such as wood fiber, ceramic fiber such as alumina fiber, wholly aromatic polyamide (aramid), wholly aromatic polyester, wholly aromatic polyester amide, wholly aromatic polyether, wholly aromatic polycarbonate, wholly aromatic poly Azomethine, polyphenylene sulfide (PPS), poly (para-phenylenebenzobisthiazole) (PBZT), polybenzimidazole (PBI), polyetheretherketone (PEEK), polyamideimide (PAI), polyimide, polytetrafluoroethylene (PTFE) ), Poly (para-phenylene-2) 6-benzobisoxazole) (PBO), and the like, those containing at least one of these is used.

  Of these, inorganic fibers such as glass fibers, carbon fibers, metal fibers, and ceramic fibers are preferably used as the long fibers. By using inorganic fibers that are excellent in mechanical properties such as tensile strength, the mechanical properties of the composite molded body 1 can be particularly enhanced.

  The fiber 3 may be subjected to a surface treatment such as a coupling agent treatment, a surfactant treatment, an ultraviolet irradiation treatment, an electron beam irradiation treatment, or a plasma irradiation treatment as necessary.

  Among these, examples of the coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyl. Dimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β- Examples include amino group-containing alkoxysilanes such as (aminoethyl) -γ-aminopropylmethyldiethoxysilane, hydrolysates thereof, and the like, and those containing at least one of these are used.

  The content of the fiber 3 in the composite molded body 1 is not particularly limited, but is preferably about 5 to 300% by volume of the resin 2, more preferably about 10 to 150% by volume, and 20 to 120% by volume. More preferably, it is about. By setting the content of the fiber 3 within the above range, the quantitative balance between the resin 2 and the fiber 3 is optimized, so that the mechanical properties of the composite molded body 1 can be particularly enhanced. That is, when the content of the fiber 3 is lower than the lower limit, the content of the fiber 3 is relatively insufficient. Therefore, depending on the composition of the resin 2, the length of the fiber 3, the constituent material, and the like, There is a risk that the mechanical properties will deteriorate. On the other hand, if the content of the fiber 3 exceeds the upper limit, the content of the resin 2 is relatively insufficient, so depending on the composition of the resin 2, the length of the fiber 3, the constituent material, and the like, There is a risk that the mechanical properties will deteriorate.

  In addition, the shape of the fiber 3 shown in FIG. 1 is an example, and is not limited to the linear shape as illustrated.

(pulp)
The composite molded body 1 may contain pulp as necessary. Pulp is a fiber material having a fibril structure and is different from the fiber 3. Pulp can be obtained, for example, by mechanically or chemically fibrillating the fiber material.

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

  Moreover, the pulp content in the composite molded body 1 is not particularly limited, but is preferably about 0.5 to 10% by mass, more preferably about 1 to 8% by mass of the resin 2. More preferably, it is about 5-5 mass%. Thereby, the composite molded object 1 with more favorable mechanical characteristics and heat conductivity is realizable.

(Flocculant)
The composite molded body 1 may contain a flocculant as necessary.

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

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

(Other additives)
The composite molded body 1 may contain other additives as necessary.

  Examples of such additives include inorganic powders, metal powders, antioxidants, ultraviolet absorbers, flame retardants, mold release agents, plasticizers, curing catalysts, curing accelerators, pigments, light proofing agents, antistatic agents, and antibacterial agents. , Conductive agents, dispersants and the like, and at least one of them is used.

(Vacancy)
Moreover, the composite molded body 1 may include pores therein. Thereby, the density (specific gravity) of the composite molded body 1 can be changed.

  The void refers to a space enclosed in the composite molded body 1. This hole may be a space (closed cell) in which one or more of the holes are connected to each other (enclosed by resin 2 or the like) and communicates with the outside of the system. It may be a space (open bubbles).

  Among these, although there is no particular limitation, it is preferable that there are more closed cells than open cells. Thereby, even if it contains a void | hole, the mechanical characteristic of the composite molded object 1 becomes difficult to fall more. This is because the closed cells are difficult to collapse, and the mechanical strength of the composite molded body 1 is not easily lowered accordingly.

  In addition, that there are more closed cells than open cells means that the total area occupied by closed cells is larger than the total area occupied by open cells when the cross section of the composite molded body 1 is enlarged and observed.

  When the composite molded body 1 contains closed cells as pores, the average diameter of the pores is not particularly limited, but is preferably about 2 to 300 μm, and more preferably about 5 to 200 μm. Thereby, weight reduction of the composite molded object 1 by a void | hole and suppression of the fall of the mechanical characteristic of the composite molded object 1 by a void | hole can be made compatible. That is, when the average diameter of the pores is lower than the lower limit, it may be difficult to reduce the weight of the composite molded body 1 depending on the porosity. On the other hand, when the average diameter of the pores exceeds the upper limit, depending on the porosity, the pores are likely to be the starting point of refraction, cracking, etc., and the mechanical properties of the composite molded body 1 may be reduced. .

  The average diameter of the holes is obtained as the diameter of the circle (equivalent circle diameter) when a circle having the same area as the hole area is assumed from the cross section of the composite molded body 1.

  The porosity of the composite molded body 1 is not particularly limited, but is preferably about 10 to 90%, more preferably about 15 to 87.5%, and further preferably about 20 to 85%. preferable. By setting the porosity within the above range, the weight reduction of the composite molded body 1 and the mechanical characteristics can be achieved in a balanced manner. That is, when the porosity is lower than the lower limit, depending on the composition of the resin 2, the length of the fiber 3, the constituent material, and the like, there is a possibility that the weight reduction of the composite molded body 1 is insufficient. On the other hand, when the porosity exceeds the upper limit, the mechanical properties of the composite molded body 1 may be lowered depending on the composition of the resin 2, the length of the fibers 3, the constituent materials, and the like. Moreover, when a void | hole contains a closed cell, the heat insulation of the composite molded object 1 improves. Thereby, since the heat conductivity in the composite molded object 1 falls, a flame retardance can be improved.

  In addition, the porosity of the composite molded body 1 is obtained, for example, as the ratio of the area occupied by the pores (the area ratio of the holes) in the cross-sectional area of the composite molded body 1.

Here, the specific strength of the composite molded body 1 is set to 50 to 400 MPa · (g / cm ³ ) ⁻¹ . Thereby, the composite molded body 1 in which both weight reduction and improvement in mechanical properties are achieved is obtained. If the specific strength falls below the lower limit, it can be said that the bending strength is small for a heavy weight. Therefore, for example, a structural material in a field where both weight reduction and high mechanical properties are required, such as an interior material for transportation equipment. May be inappropriate. On the other hand, if the specific strength exceeds the above upper limit value, it can be said that the bending strength is large for light weight, but depending on the balance with other physical properties, the impact resistance is reduced, and variations due to manufacturing conditions are likely to occur. It may be difficult to increase the manufacturing yield.

Further, the specific strength of the composite compact 1, more preferably from 100~390MPa · ^{(g /} cm ³⁾ about ^-1, even more preferably 150~380MPa · ^{(g /} cm ³⁾ about ^-1 .

The specific strength of the composite molded body 1 can be obtained by dividing the bending strength (unit: MPa) by the density (unit: g / cm ³ ).

Moreover, it is preferable that the composite molded object 1 has the following characteristics.
First, the density of the composite compact 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 or so, More preferably, it is about 0.2 to 1.5 g / cm ³ . As a result, a composite molded body 1 that achieves both weight reduction and improved mechanical properties is obtained.

  In addition, a density is measured according to the test method prescribed | regulated as A method in JISK7112: 1999.

  Further, the bending strength of the composite molded body 1 is not particularly limited, but is preferably about 50 to 400 MPa, more preferably about 70 to 350 MPa, and further preferably about 100 to 300 MPa. Thereby, the composite molded body 1 having sufficiently high mechanical properties can be obtained.

  The flexural strength of the composite molded body 1 is measured at room temperature (25 ° C.) according to a test method defined in ISO 178: 2001.

Further, specific modulus of the composite molded body 1 is not particularly limited, but is preferably 2~30GPa · ^{(g /} cm ³⁾ about ^{-1, 3~25GPa · (g / cm} 3) at about ^-1 More preferably, it is about 4 to 20 GPa · (g / cm ³ ) ⁻¹ . Thereby, the composite molded body 1 in which both weight reduction and improvement in mechanical properties are achieved is obtained.

The specific elastic modulus of the composite molded body 1 can be obtained by dividing the bending elastic modulus (unit: GPa) by the density (unit: g / cm ³ ). And a bending elastic modulus is measured according to the test method prescribed | regulated to ISO178: 2001 at room temperature (25 degreeC).

  As described above, the composite molded body 1 includes the resin 2 and the fibers 3, and the fibers 3 include long fibers. According to such a composite molded body 1, since the very long fiber 3 is included, a high mechanical strength can be obtained. Thereby, the use of the composite molded object 1 can be extended to the field | area which could not use a composite molded object conventionally. As a result, the composite molded body 1 applicable as a structural material in various fields can be obtained without impairing the advantage of weight reduction.

<Method for producing composite molded body>
Next, an embodiment of a method for producing a composite molded body of the present invention will be described.

  2-6 is a figure for demonstrating an example of the method of manufacturing the composite molded object shown in FIG. 1, respectively.

  The manufacturing method of the composite molded body 1 includes a step of preparing a dispersion containing the resin 2 and the fiber 3, a step of making the dispersion to obtain the intermediate 10, and pressure-molding the intermediate 10 while heating. A step of melting at least a part of the resin 2 to obtain the composite molded body 1. Hereinafter, each process will be described sequentially.

  [1] First, as shown in FIG. 2, a dispersion 6 containing a resin 2, fibers 3, and a dispersion medium 5 in which these are dispersed is prepared. The prepared dispersion 6 is sufficiently stirred and mixed. The dispersion 6 may contain the above-described flocculant, pulp, other additives, and the like as necessary.

  The shape of the resin 2 is not particularly limited, and may be, for example, a particle shape (powder shape) such as a substantially spherical particle shape or a thin film particle shape, or a fiber shape. Thereby, in the papermaking mentioned later, the resin 2 can be picked up with the fiber 3. As a result, the resin 2 and the fiber 3 can be intertwined, and the intermediate body 10 capable of producing the homogeneous composite molded body 1 is obtained (see FIG. 5).

  In addition, when the resin 2 contains a thermosetting resin, it is preferable that the thermosetting resin is a semi-hardened state. The semi-cured thermosetting resin is formed into a desired shape by heating and pressurization after the intermediate 10 is manufactured, and then cured. Thereby, the composite molded object 1 which utilized the characteristic of the thermosetting resin will be obtained.

  On the other hand, as the fiber 3, for example, a fiber having a melting point higher than that of the resin 2 is used. By using such a fiber 3, only the resin 2 can be selectively melted when the intermediate body 10 is pressure-molded while being heated in a process described later. As a result, the resin 2 can be melted and dispersed around the fibers 3, and a homogeneous composite molded body 1 can be obtained.

  The melting point of the fiber 3 is preferably higher than the melting point of the resin 2, and the difference is more preferably 10 ° C. or more, and further preferably 50 ° C. or more.

  Among these, as the fibers 3, inorganic fibers such as glass fibers, carbon fibers, metal fibers, and ceramic fibers are preferably used. By using inorganic fibers that are excellent in mechanical properties such as tensile strength, the mechanical properties of the composite molded body 1 can be particularly enhanced. In addition, since inorganic fibers generally have a very high melting point, there is almost no possibility of melting when the intermediate 10 is heated. For this reason, even when a material having a high melting point is used as the constituent material of the resin 2, the composite molded body 1 can be reliably manufactured.

  Further, as the dispersion medium 5, a medium that is difficult to dissolve the resin 2 and the fibers 3 and that hardly volatilizes in the process of dispersing the resin 2 and the fibers 3 is preferably used. Moreover, what is easy to remove a solvent is used preferably. From this viewpoint, the boiling point of the dispersion medium 5 is preferably about 50 to 200 ° C.

  Examples of the dispersion medium 5 include alcohols such as water, ethanol, 1-propanol, 1-butanol, and ethylene glycol, ketones such as acetone, methyl ethyl ketone, 2-heptanone, and cyclohexanone, ethyl acetate, butyl acetate, and acetoacetate. Examples 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.

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

  In addition, the viscosity of the dispersion 6 can be adjusted by appropriately setting the concentration of the aggregating agent (fixing agent) described above. Specifically, the concentration of the flocculant added to the dispersion 6 is preferably 50 to 1000 ppm and more preferably 100 to 500 ppm in terms of mass ratio. Thereby, the viscosity of the dispersion liquid 6 is optimized, and the fiber 3 can be uniformly dispersed in the dispersion liquid 6. As a result, it is possible to efficiently produce a composite molded body 1 that is homogeneous and has high mechanical strength.

  If the concentration of the flocculant in the dispersion 6 is lower than the lower limit, the viscosity of the dispersion 6 becomes too low, so that it is difficult to uniformly disperse the fibers 3 due to aggregation of the fibers 3 and the like. There is. On the other hand, when the concentration of the flocculant in the dispersion liquid 6 exceeds the upper limit, the viscosity of the dispersion liquid 6 becomes too high, so that a long time is required for the dehydration and drying processes of the agglomerates. May decrease.

  [2] Subsequently, the prepared dispersion 6 is made. Thereby, the intermediate body 10 for manufacturing the composite molded object 1 is obtained.

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

  Next, the dispersion 6 is supplied into the container 70. Then, the dispersion medium 5 in the dispersion liquid 6 is discharged from the bottom surface of the container 70 through the filter 71 to the outside. Thereby, the resin 2 and the fiber 3 which are dispersoids in the dispersion liquid 6 remain on the filter 71 (papermaking). The intermediate 10 is obtained on the filter 71 as described above.

  At this time, the intermediate body 10 having a desired shape can be manufactured by appropriately selecting the shape of the filter 71.

  The intermediate 10 obtained in this way may or may not contain the dispersion medium 5.

  Thereafter, as shown in FIG. 4, the intermediate body 10 is disposed between the press die 72 and the press die 73 as necessary, and a cavity (not shown) formed between the press die 72 and the press die 73 is formed. To compress the intermediate 10.

For example, by lowering the press die 72 as indicated by an arrow P, the intermediate body 10 is compressed between the press die 72 and the press die 73. Thereby, the dispersion medium 5 remaining in the intermediate 10 can be sufficiently discharged, and the intermediate 10 can be dried.
In addition, you may make it dry with a dryer etc. as needed.

  In addition, when a fibrous material is used as the resin 2, it is possible to obtain an intermediate 10 having a particularly small apparent density. Such an intermediate body 10 makes it possible to manufacture a composite molded body 1 having a low density by appropriately setting the conditions in pressure molding described later. That is, the composite molded body 1 that is sufficiently lightened 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 fibers 3 is further increased. Thereby, the width | variety of the porosity which can be implement | achieved in the composite molded object 1 manufactured can be taken more widely.

  In addition, although the upper limit of the average length of resin 2 which makes | forms fibrous form is not specifically limited, For example, it is preferable that it is 100 mm or less, and it is more preferable that it is 50 mm or less. Thereby, when manufacturing the composite molded object 1, when disperse | distributing the resin 2 which makes | forms fibrous to the dispersion medium 5, the dispersibility becomes favorable. As a result, since the intermediate body 10 having a homogeneous structure is obtained, the composite molded body 1 having excellent mechanical properties is finally obtained.

  In addition, the average length of the resin 2 having a fibrous shape refers to a value obtained by measuring and averaging the length of any 100 or more fibrous resins 2.

  Further, the average length of the resin 2 in the form of a fiber is preferably about 10 to 1000%, more preferably about 20 to 500% of the average length of the fibers 3. As a result, the degree of entanglement between the fibrous resin 2 and the fiber 3 becomes more prominent, so that the shape retention of the intermediate body 10 becomes better, and a composite molded body having a wider range of porosity. 1 is obtained, which can produce 1 easily.

  Moreover, the average diameter of the resin 2 in the form of a fiber 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. It becomes easy to maintain a uniformly dispersed state. As a result, the width of the porosity that can be realized in the manufactured composite molded body 1 can be made wider.

  In addition, the average diameter of the resin 2 having a fibrous shape refers to a value obtained by measuring and averaging the diameters of any 100 or more fibrous resins 2.

  Further, the ratio of the length to the diameter of the resin 2 in the form of a fiber (length / diameter) is preferably 10 or more, and more preferably 100 or more. Thereby, the resin 2 which makes fibrous form exhibits the above effects more reliably.

On the other hand, the dispersion 6 may contain thermally expandable microcapsules.
The thermally expandable microcapsule is a particle obtained by microencapsulating a volatile liquid foaming agent with a thermoplastic shell polymer having gas barrier properties. Such a thermally expandable microcapsule functions as a foaming agent by the following mechanism. That is, while the outer shell of the capsule is softened by heating, the liquid foaming agent contained in the capsule is vaporized and the pressure is increased. As a result, the capsule expands and hollow spherical particles are formed. The hollow spherical particles remain even after the pressure molding, and consequently contribute to reducing the density of the composite molded body 1. Therefore, the composite molded body 1 having a low density can be obtained.

  Examples of the liquid blowing 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-methyl methacrylate copolymer, vinylidene chloride-ethyl methacrylate, acrylonitrile-methyl methacrylate copolymer, acrylonitrile-ethyl methacrylate, and the like. These may be used alone or in combination of two or more.

  Examples of the thermally expandable microcapsule include EXPANSEL (manufactured by Nippon Ferrite Co., Ltd.), Microsphere F50, Microsphere F60 (above, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), Advancel EM (manufactured by Sekisui Chemical Co., Ltd.) Commercial products can be used.

  The content of the thermally expandable microcapsule is preferably about 0.05 to 10% by mass of the resin 2 and more preferably about 0.1 to 5% by mass. Thereby, a certain degree of mechanical strength can be ensured while reducing the density of the composite molded body 1.

  [3] Next, the intermediate 10 is pressure-formed while being heated. Thereby, at least a part of the resin 2 in the intermediate body 10 is melted, and the composite molded body 1 is obtained.

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

  For example, the intermediate body 10 is compressed between the molding die 74 and the molding die 75 by lowering the molding die 74 as indicated by an arrow P. At this time, since the resin 2 is heated at the same time, at least a part of the resin 2 melts and flows between the fibers 3 to function as a binder for binding the fibers 3 together. Then, the fibers 3 are bound by the resin 2 as the resin 2 is cured. Thereby, the composite molded body 1 is obtained from the intermediate 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.

  Moreover, although the heating time at this time is suitably set according to heating temperature, it is preferable that it is about 1 to 180 minutes, and it is more preferable that it is about 5 to 60 minutes.

  Moreover, although the applied pressure at this time is suitably set according to heating temperature and heating time, it is preferable that it is about 0.05-80 MPa, and it is more preferable that it is about 0.1-60 MPa.

  In addition, it is possible to adjust the porosity of the composite molded body 1 by appropriately changing the conditions in this step. For example, when the heating temperature is lowered, the heating time is shortened, or the applied pressure is reduced, the composite molded body 1 having a relatively high porosity can be obtained. On the other hand, when the heating temperature is increased, the heating time is increased, or the applied pressure is increased, the composite molded body 1 having a relatively low porosity can be obtained.

  As mentioned above, although the composite molded object and the manufacturing method of the composite molded object of this invention were demonstrated based on embodiment of illustration, this invention is not limited to these.

  For example, the composite molded body of the present invention may be obtained by adding an arbitrary element to the embodiment.

  Moreover, the manufacturing method of the composite molded object of this invention may add the arbitrary process to the said embodiment, and may replace the order of each process of the said embodiment.

Next, specific examples of the present invention will be described.
1. Production of composite molded body (Example 1)
[1] First, resol type phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., product number PR-51723), aramid fiber (manufactured by Teijin Ltd., product number T32PNW, average length 20 mm, average diameter 12 μm), and aramid pulp (DuPont) Manufactured, product number para-aramid pulp) and water, and 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 blending ratio is as shown in Table 1.

  Next, a flocculant (polyethylene oxide, molecular weight 1000000) previously dissolved in water was added to the obtained dispersion at a concentration of 0.03% by mass (300 ppm by mass).

[2] Next, the dispersion was filtered through a 40-mesh metal screen (screen), and the aggregate was dehydrated and pressed at a pressure of 3 MPa to remove water.
Next, the dehydrated aggregate was dried at 50 ° C. for 5 hours to obtain an intermediate.

[3] Next, an intermediate was placed in the cavity of the mold.
Next, the intermediate was pressure molded to a thickness of 4 mm while heating the mold. The heating temperature at this time was 180 ° C., the applied pressure was 2 MPa, and the pressing time was 10 minutes.
Thus, a composite molded body was obtained.

(Examples 2 to 14)
A composite molded body was obtained in the same manner as in Example 1 except that the production conditions of the composite molded body were changed as shown in Table 1 or Table 2. The concentration of the flocculant in the dispersion was 50 to 1000 ppm in mass ratio.
“PEI” in Tables 1 and 2 refers to polyetherimide.

(Comparative Examples 1-6)
A composite molded body was obtained in the same manner as in Example 1 except that the production conditions of the composite molded body were changed as shown in Table 1 or Table 2.

2. 2. Evaluation of Composite Molded Body 2.1 Evaluation of Density First, the density of the composite molded body of each example and each comparative example was measured by a method based on the A method of JIS K 7112: 1999. The measurement results are shown in Tables 1 and 2.

2.2 Evaluation of impact strength Next, the impact strength of each composite molded body of each example and each comparative example was measured by a method based on ASTM D3763.

  And about the composite molded object of Examples 1-6 and the comparative example 1, the relative value when the impact strength of the composite molded object of the comparative example 2 was set to 1 was computed.

  For the composite molded body of Example 7, the relative value when the impact strength of the composite molded body of Comparative Example 3 was 1 was calculated.

  For the composite molded bodies of Examples 8 to 13 and Comparative Example 4, relative values were calculated when the impact strength of the composite molded body of Comparative Example 5 was 1.

For the composite molded body of Example 14, the relative value when the impact strength of the composite molded body of Comparative Example 6 was 1 was calculated.
Next, the calculated relative value was evaluated according to the following evaluation criteria.

<Evaluation criteria for impact strength>
A: Relative value is 1.75 or more B: Relative value is 1.50 or more and less than 1.75 C: Relative value is 1.25 or more and less than 1.50 D: Relative value is 1.00 or more It is less than 1.25 E: The relative value is 0.75 or more and less than 1.00 F: The relative value is less than 0.75 The evaluation results are shown in Tables 1 and 2.

2.3 Evaluation of toughness Next, the impact energy of each composite molded body of each example and each comparative example was measured by a method based on ASTM D3763.

  And about the composite molded object of Examples 1-6 and the comparative example 1, the relative value when the impact energy of the composite molded object of the comparative example 2 was set to 1 was computed.

  For the composite molded body of Example 7, the relative value was calculated when the impact energy of the composite molded body of Comparative Example 3 was 1.

  For the composite molded bodies of Examples 8 to 13 and Comparative Example 4, relative values were calculated when the impact energy of the composite molded body of Comparative Example 5 was 1.

  For the composite molded body of Example 14, the relative value when the impact energy of the composite molded body of Comparative Example 6 was 1 was calculated.

  Next, toughness was evaluated by illuminating the calculated relative values against the following evaluation criteria. In addition, it shows that toughness is so large that the relative value of impact energy is large.

<Evaluation criteria for toughness>
A: Relative value is 1.75 or more B: Relative value is 1.50 or more and less than 1.75 C: Relative value is 1.25 or more and less than 1.50 D: Relative value is 1.00 or more It is less than 1.25 E: The relative value is 0.75 or more and less than 1.00 F: The relative value is less than 0.75 The evaluation results are shown in Tables 1 and 2.

  As is clear from Tables 1 and 2, it was confirmed that the composite molded body of each example had higher mechanical strength than the composite molded body of the comparative example.

DESCRIPTION OF SYMBOLS 1 Composite molded object 2 Resin 3 Fiber 5 Dispersion medium 6 Dispersion liquid 10 Intermediate body 70 Container 71 Filter 72 Press mold 73 Press mold 74 Mold mold 75 Mold

Claims (6)

Resin and fiber,
A composite molded body comprising long fibers having a length of 20 mm or more as the fibers.   The composite molded body according to claim 1, further comprising short fibers having a length of less than 20 mm as the fibers.   The composite molded article according to claim 1 or 2, wherein a ratio of the long fibers among the fibers is 50% by mass or more.   The composite molded body according to any one of claims 1 to 3, wherein the long fibers are inorganic fibers.   The composite molded body according to any one of claims 1 to 4, wherein the resin includes a thermoplastic resin. A method for producing the composite molded article according to any one of claims 1 to 5,
Preparing a dispersion containing the resin, the long fibers, and a fixing agent, wherein the concentration of the fixing agent is 50 to 1000 ppm by mass,
Paper making the dispersion to obtain an intermediate;
Obtaining the composite molded body by pressure-molding the intermediate; and
The manufacturing method of the composite molded object characterized by having.

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