JPWO2019093192A1 - Fiber-containing resin composition - Google Patents

Abstract

The fiber 2 is a resin composition solidified with the thermosetting resin 1, the thermosetting resin 1 includes a resol type phenol resin, and the fiber 2 has an average length in the range of 1 to 50 mm. A fiber-containing resin structure S in which the content of the resol type phenol resin in the curable resin is 50% by mass or more is provided. In such a resin composition, the fibers 2 are preferably dispersed in the thermoset resin 1 in an opened state. Thereby, the heat resistance of the hardened | cured material of the fiber containing resin structure S improves more.

Description

  The present invention relates to a fiber-containing resin composition.

  In recent years, as a substitute for metal parts, a fiber reinforced resin cured product or a fiber reinforced resin molded product (Patent Document 1) that is molded using a thermosetting resin or a thermoplastic resin containing fibers has been attracting attention. . In addition, as a general molding method of such a resin cured product or resin molded product, compression molding (Patent Document 2), transfer molding (Patent Document 3), transfer-compression molding, injection ( Injection) molding and injection-compression molding (Patent Document 4) are known.

  By the way, in order to improve mechanical strength such as tensile strength, bending strength, impact resistance, etc., the fiber reinforced resin cured product or resin molded product has a length of 5 to 30 mm as a fiber mixed in the resin. A relatively long fiber (so-called long fiber) is preferably used. In manufacture of the hardened | cured material and molded article mentioned above, the pellet which hardened the long fiber bundle with resin as a form which supplies resin and fiber used as material, and the aggregate | assembly which hardened them are used (patent document 5). If such pellets or aggregates thereof are used, fibers having a uniform length can be supplied into the resin.

JP 07-290902 A Japanese Patent Application Laid-Open No. 06-246771 JP 2006-130731 A JP 2002-127215 A JP 2012-096370 A

  However, the conventional fiber reinforced resin cured product using the above-described pellets and aggregates has a problem of poor heat resistance.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the resin composition which can manufacture the fiber reinforced resin hardened | cured material by which the heat resistance improvement was aimed at.

In order to solve the above problems, the following means are provided.
(1) A fiber-containing resin composition in which fibers are hardened with a thermosetting resin,
The thermosetting resin includes a resol type phenol resin,
The fibers have an average length in the range of 1-50 mm,
Content of the said resol type phenol resin in the said thermosetting resin is 50 mass% or more, The fiber containing resin composition characterized by the above-mentioned.

(2) The fibers are dispersed in the opened state in the thermosetting resin,
The average length of the fibers is in the range of 1-20 mm,
The fiber-containing resin composition according to (1), wherein the average density of the fiber-containing resin composition is in the range of 0.20 to 1.00 (g / cm ³ ).

(3) The fibers are dispersed in the opened state in the thermosetting resin,
The average length of the fibers is in the range of 1-20 mm,
The fiber-containing resin composition according to the above item (1) or (2), wherein an average bulk density of the fiber-containing resin composition is in a range of 0.15 to 0.60 (g / cm ³ ).

(4) The fiber-containing resin composition according to any one of (1) to (3), wherein the thermosetting resin further includes a novolac type phenol resin.

(5) Ratio of content A (mass%) of the resol type phenol resin contained in the thermosetting resin and content B (mass%) of the novolac type phenol resin contained in the thermosetting resin The fiber-containing resin composition according to item (4), wherein the A / B value is in the range of 1 to 5.

(6) Any one of (1) to (5) above, further comprising at least one selected from the group consisting of a phosphorus-based antioxidant, a hindered phenol-based antioxidant, and an amine-based antioxidant. The fiber-containing resin composition described in 1.

(7) The fiber-containing resin composition according to any one of (1) to (6), further including an inorganic filler other than the fibers.

(8) The fiber-containing resin composition according to any one of (1) to (7), which is used for a structural member.

  According to the fiber-containing resin composition of the present invention, a fiber-reinforced resin cured product with improved heat resistance can be produced.

FIG. 1 is a photograph showing the appearance of one embodiment (pellet P) of a fiber-containing resin composition to which the present invention is applied. Fig.2 (a) is a photograph which shows other embodiment (resin structure S) of the fiber containing resin composition to which this invention is applied. FIG. 2B is a schematic diagram for explaining the configuration of the resin structure S. FIG. 3 is a schematic diagram for explaining an embodiment of a method for producing the resin structure S. FIG. 4 is a schematic view for explaining another embodiment of the method for producing the resin structure S. FIG. 5 is a schematic diagram for explaining an embodiment of a method for producing the resin structure T. Fig.6 (a) is an image which shows the cut surface of the test piece (after 250-hour heat processing under 280 degreeC) using the fiber containing resin composition of Example 1. FIG. FIG. 6B is an image showing a cut surface of a test piece (after heat treatment at 280 ° C. for 250 hours) in which the fiber-containing resin composition of Comparative Example 2 was used. FIG.6 (c) is an image which shows the cut surface of the test piece (after 250-hour heat processing under 280 degreeC) in which the fiber containing resin composition of Example 5 was used. FIG.6 (d) is an image which shows the cut surface of the test piece (after 250-hour heat processing under 280 degreeC) in which the fiber containing resin composition of the comparative example 1 was used.

  Hereinafter, regarding the fiber-containing resin composition that is an embodiment to which the present invention is applied, the resin composition, a method for producing the resin composition, and the configuration of a cured fiber-reinforced resin using the resin composition as a raw material will be described in detail. In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, there are cases where the characteristic portions are enlarged for convenience, and the dimensional ratios of the respective components are the same as the actual dimensions. Is not limited.

(Fiber-containing resin composition)
First, the configuration of a fiber-containing resin composition (hereinafter also simply referred to as “resin composition”) as an embodiment to which the present invention is applied will be described.
In the resin composition according to the present invention, the fibers are hardened with a thermosetting resin.

  FIG. 1 is a photograph showing the appearance of one embodiment (pellet P) of a fiber-containing resin composition to which the present invention is applied. The pellet P is a structure in which a bundle of long fibers is hardened with a specific resin.

  FIG. 2 shows another embodiment (resin structure S) of the fiber-containing resin composition to which the present invention is applied. FIG. 2A is a photograph showing the appearance of the resin structure S. FIG. 2B is a schematic diagram for explaining the configuration of the resin structure S.

  As shown in FIG. 2B, the resin structure S of the present embodiment is schematically configured to include a thermosetting resin 1 and fibers 2. The resin structure S is a granular resin structure that contains a thermosetting resin and fibers and in which the fibers 2 are dispersed in a state of being opened in the thermosetting resin.

Here, in the resin structure S of the present embodiment, “the state of being opened in the thermosetting resin” refers to a state in which the fiber bundles are scattered and the fibers are spread in the thermosetting resin.
In the resin structure S of the present embodiment, the “state in which the fibers are dispersed” refers to a state in which it is not recognized that the fibers are substantially oriented in only one direction as a whole.

  Since this resin structure S is granular, it can be easily weighed when used as a raw material for compression molding or the like. Moreover, the resin structure S can be used as a raw material at the time of manufacturing a fiber reinforced resin cured product.

<< Thermosetting resin >>
The resin composition (pellet P, resin structure S) of the present embodiment contains a thermosetting resin including a resol type phenol resin.
By applying the thermosetting resin, mechanical properties such as linear expansion coefficient after curing and elastic modulus are excellent. In addition, by adopting a resol type phenolic resin, it is possible to produce a cured fiber reinforced resin with low cost and high dimensional accuracy, and the obtained cured fiber reinforced resin exhibits particularly excellent heat resistance. Can do.

Examples of the resol type phenol resin include an unmodified resol type phenol resin synthesized with phenol and formaldehyde; a modified resol phenol resin modified with paulownia oil, linseed oil, walnut oil, etc .; a part or all of the phenol is cresol or naphthol. Resole resins synthesized by substituting for, and the like can be used, and one or more of these can be used in combination.
The weight average molecular weight of the resol type phenol resin is preferably 1000 to 100,000. If the weight average molecular weight is less than the lower limit, it may be difficult to prepare pellets because the resin viscosity is too low, and if it exceeds the upper limit, the resin melt viscosity becomes high, so fiber reinforcement The moldability (ease of molding) of the cured resin product may be reduced.
The weight average molecular weight of the phenol resin is measured by, for example, gel permeation chromatography (GPC) and can be defined as a weight molecular weight in terms of polystyrene.

In the present embodiment, the ratio of the resol type phenol resin contained in the applied thermosetting resin is 50% by mass or more of the total amount (100% by mass) of the thermosetting resin.
By the way, the resol type phenol resin has a structure in which a functional group such as a methylol group is added to each phenol molecule, and has a property of self-curing by heat or the like. That is, the resol type phenol resin does not require a curing agent for the curing reaction unlike a general thermosetting resin. Such a resol type phenolic resin is cured by a dehydration condensation reaction of a methylol group added to each phenol molecule, so that it is a general thermosetting resin that is cured using a curing agent (for example, a novolac type phenolic resin). ), A uniform cross-linked structure is formed, so that the heat resistance and mechanical strength can be increased.
For the above reasons, when the content of the resol type phenol resin in the thermosetting resin is 50% by mass or more, the heat resistance of the obtained fiber reinforced resin cured product can be easily increased. Moreover, 60 mass% or more is preferable, as for content of the resol type phenol resin contained in a thermosetting resin, 70 mass% or more is more preferable, and 100 mass% may be sufficient. When the ratio of the resol type phenol resin is equal to or more than the lower limit, the heat resistance of the obtained fiber reinforced resin cured product is easily increased.

The applied thermosetting resin may include a thermosetting resin other than the resol type phenol resin.
Examples of thermosetting resins other than resol type phenol resins include novolak type phenol resins, epoxy resins, bismaleide resins, urea (urea) resins, melamine resins, polyurethane resins, cyanate ester resins, silicone resins, oxetane resins, (meta ) An acrylate resin, an unsaturated polyester resin, a diallyl phthalate resin, a polyimide resin, a benzoxazine resin and the like can be used, and one or more of these can be used in combination.
Among these, as the thermosetting resin used in combination with the resol type phenol resin, a novolak type phenol resin, an epoxy resin, a bismaleide resin, a benzoxazine resin, and an unsaturated polyester resin are preferable, and a novolac type phenol resin, an epoxy resin, and a bismaleide resin are preferable. 1 or more types selected from the group consisting of are more preferable, and novolak type phenol resins are more preferable. Thereby, the heat resistance of the obtained fiber reinforced resin hardened | cured material is improved more.

Examples of the novolak type phenol resin include phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, arylalkylene type novolak resin, and the like.
As for the weight average molecular weight of a novolak-type phenol resin, 1000-15000 are preferable.

When using a resol type phenol resin and a novolac type phenol resin together, 1-5 are preferable, 2-5 are more preferable, 2-5 are more preferable, 2-4 are still more preferable. 5-3.5 is particularly preferable. In addition, the said mass ratio is ratio of content rate A (mass%) of the resol type phenol resin contained in a thermosetting resin, and content rate B (mass%) of the novolak type phenol resin contained in a thermosetting resin. It is represented by A / B.
When the mass ratio (resole type / novolak type) is equal to or higher than the lower limit value, the heat resistance of the obtained fiber reinforced resin cured product is further improved, and when the mass ratio is equal to or lower than the upper limit value, mechanical properties of the fiber reinforced resin cured product are obtained. Is easy to keep.

Examples of the epoxy resin include bisphenol resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type phenol resin; novolak type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; bromine Brominated epoxy resins such as bisphenol A type epoxy resin and brominated phenol novolac type epoxy resin; biphenyl type epoxy resin; naphthalene type epoxy resin, tris (hydroxyphenyl) methane type epoxy resin, etc. One kind or a combination of two or more kinds can be used.
Among these, bisphenol A type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins having a relatively low molecular weight are particularly preferable. Thereby, since the fluidity | liquidity of a resin composition can be improved, the handleability and moldability (easiness of shaping | molding) of the resin composition at the time of manufacture of a fiber reinforced resin hardened | cured material can be made further favorable. In addition, a tris (hydroxyphenyl) methane type epoxy resin is particularly preferable because the heat resistance of the cured fiber reinforced resin is easily improved.

  The bismaleimide resin is not particularly limited as long as it has a maleimide group at both ends of the molecular chain, but a resin having a phenyl group is preferable. Specifically, for example, a resin represented by the following formula (1) can be used. However, the bismaleimide resin may have maleimide groups that bind to positions other than both ends of the molecular chain.

In formula (1), R ^{1 to} R ⁴ are hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 4 carbon atoms, and R ⁵ is a divalent substituted or unsubstituted organic group. Here, the organic group is a hydrocarbon group that may contain a heteroatom, and examples of the heteroatom include O, S, and N. R ⁵ is preferably a hydrocarbon group having a main chain in which a methylene group, an aromatic ring, and an ether bond (—O—) are bonded in any order, and more preferably methylene bonded in any order in the main chain A hydrocarbon group having a total number of groups, aromatic rings and ether bonds of 15 or less. In the middle of the main chain, a substituent and / or a side chain may be bonded, and specific examples thereof include a hydrocarbon group having 3 or less carbon atoms, a maleimide group, a phenyl group, and the like. It is done.

  Specifically, for example, N, N ′-(4,4′-diphenylmethane) bismaleimide, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, 2,2-bis [4- (4 -Maleimidophenoxy) phenyl] propane, m-phenylenebismaleimide, p-phenylenebismaleimide, 4-methyl-1,3-phenylenebismaleimide, N, N'-ethylenedimaleimide, N, N'-hexamethylenedimaleimide These can be used, and one or more of these can be used in combination.

The content of the thermosetting resin in the resin composition of the present embodiment is preferably 50% by mass or less, more preferably 5 to 50% by mass, more preferably 10 to 45% of the total amount (100% by mass) of the resin composition. % By mass is more preferable, and 20 to 45% by mass is particularly preferable.
If the content of the thermosetting resin is less than or equal to the above upper limit value, the amount of fibers can be increased, and the heat resistance of the fiber reinforced resin cured product can be easily improved by reducing the components that deteriorate due to heating. When it is at least the lower limit, the binding strength with other components constituting the resin composition can be easily increased.

<< fiber >>
The resin composition (pellet P, resin structure S) of this embodiment contains fibers having an average length in the range of 1 to 50 mm.
When the average fiber length (average fiber length) is less than the lower limit, the shape stability of the cured resin product may not be sufficiently obtained depending on the constituent material of the fiber and its content. When the average fiber length exceeds the upper limit, the resin composition may not be sufficiently fluid during molding.

The average length (average fiber length) of the fibers contained in the pellet P is preferably 3 mm or more and 50 mm or less, more preferably 5 mm or more and 40 mm or less, and further preferably 8 mm or more and 30 mm or less.
The average length (average fiber length) of the fibers contained in the resin structure S is preferably 1 mm or more and 20 mm or less, more preferably 1 mm or more and 15 mm or less, and further preferably 2 mm or more and 10 mm or less. 2 mm or more and 8 mm or less is particularly preferable.
In the resin composition (pellet P, resin structure S) of this embodiment, the mechanical strength of the finally obtained resin cured product can be further improved by applying fibers having such an average length, In addition, heat resistance can be improved.

In addition, the average length (average fiber length) of the fiber contained in the resin composition (pellet P, resin structure S) of this embodiment can be calculated by the following procedures (1) to (3). .
Procedure (1) The whole resin composition is heated at 550 ° C. using an electric furnace to vaporize the resin, and then only the fibers are taken out.
Procedure (2) The length of the fiber is measured using a microscope (number of fibers measured: 500 per sample).
Procedure (3) The weight average fiber length is calculated from the measured fiber length.

  The average diameter of the fibers is preferably 5 to 20 μm, more preferably 6 to 18 μm, and further preferably 7 to 16 μm. When the average diameter of the fibers is less than the lower limit value, the fibers are likely to be damaged during molding depending on the constituent material and content of the fibers. Moreover, when the average diameter of the fiber exceeds the upper limit, the formability may be lowered depending on the constituent material of the fiber and its content.

  The cross-sectional shape of the fiber is not particularly limited, and may be any shape such as a substantially circular shape such as circular and elliptical copper; a polygon such as a triangle, a quadrangle, and a hexagon; Among these, the cross-sectional shape of the fiber is particularly preferably substantially circular or flat. Thereby, the smoothness of the surface of the cured resin can be improved. Moreover, the handleability at the time of shaping | molding improves more, and the moldability becomes further favorable.

  Examples of fibers include organic fibers such as aramid fibers, acrylic fibers, nylon fibers (aliphatic polyamide fibers), and phenol fibers; glass fibers, carbon fibers, ceramic fibers, rock wool, potassium titanate fibers, and basalt fibers. Inorganic fibers; metal fibers such as stainless fibers, steel fibers, aluminum fibers, copper fibers, brass fibers and bronze fibers, and the like, and one or more of these can be used in combination. Among these, as a fiber, it is more preferable that they are an aramid fiber, carbon fiber, and glass fiber especially.

When glass fiber is used, the uniformity of the cured resin per unit volume is improved and the moldability is particularly good. Furthermore, by improving the uniformity of the cured resin, the uniformity of the internal stress in the cured resin is improved, and as a result, the swell of the cured resin is reduced. In addition, the wear resistance of the cured resin under high load can be further improved.
Moreover, when carbon fiber or aramid fiber is used, the mechanical strength of the cured resin can be further increased, and the weight of the cured resin can be further reduced.

  Specific examples of the glass constituting the glass fiber include, for example, E glass, C glass, A glass, S glass, D glass, NE glass, T glass, and H glass. Among these, as glass constituting the glass fiber, E glass, T glass, or S glass is particularly preferable. By using such glass fiber, it is possible to achieve high elasticity of the fiber and to reduce its thermal expansion coefficient.

  Specific examples of the carbon fiber include a high-strength carbon fiber having a tensile strength of 3500 MPa or more and a high-modulus carbon fiber having an elastic modulus of 230 GPa or more. The carbon fiber may be either a polyacrylonitrile (PAN) -based carbon fiber or a pitch-based carbon fiber, but is preferably a polyacrylonitrile-based carbon fiber because of its high tensile strength.

  The aramid resin constituting the aramid fiber may have either a meta-type structure or a para-type structure.

  Moreover, it is preferable that the fiber is surface-treated beforehand. By performing the surface treatment in advance, the fibers can increase the dispersibility in the resin composition or the cured resin, increase the adhesion with the resin, and the like.

  Examples of the surface treatment method include a coupling agent treatment, an oxidation treatment, an ozone treatment, a plasma treatment, a corona treatment, and a blast treatment, and one or more of these may be combined. Can be used. Among these, the coupling agent treatment is particularly preferable.

  The coupling agent used for the coupling agent treatment is not particularly limited and can be appropriately selected depending on the type of resin.

  Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent, and one or more of these can be used in combination. Among these, a silane coupling agent is particularly preferable. Thereby, especially the adhesiveness with respect to a thermosetting resin improves a fiber.

  Silane coupling agents include epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, vinyl silane coupling agents, mercapto silane coupling agents, methacryl silane coupling agents, chlorosilane coupling agents, and acrylic silanes. A coupling agent etc. are mentioned.

The fiber content in the resin composition of the present embodiment is preferably 35% by mass or more, more preferably more than 35% by mass, and further 40 to 80% by mass of the total amount (100% by mass) of the resin composition. It is preferably 45 to 75% by mass, and most preferably 50 to 70% by mass. Thereby, the mechanical strength of the resin cured material obtained can be improved more efficiently.
Further, when the fiber content is at least the lower limit, it becomes easy to improve the heat resistance of the fiber reinforced resin cured product. When the fiber content is not more than the upper limit, the fiber content is combined with other components constituting the resin composition. It becomes easy to increase the wearing strength.
In the resin composition (pellet P, resin structure S) of this embodiment, it is possible to mix | blend a larger amount of fibers stably, for example, the content rate of a fiber is the total amount (100 mass) of a resin composition. %)), A resin composition of 55% by mass or more, particularly 60% by mass or more can also be prepared.

<< Other ingredients >>
The resin composition (pellet P, resin structure S) of the present embodiment includes, in addition to the thermosetting resin and fibers, an antioxidant, a resin other than the thermosetting resin, a curing agent, and a curing as necessary. Auxiliaries, fillers, release agents, pigments (such as carbon black), sensitizers, acid multipliers, plasticizers, flame retardants, stabilizers or antistatic agents may be contained.

  Although it does not specifically limit as antioxidant, For example, phosphorus antioxidant, hindered phenol antioxidant, amine antioxidant, hindered amine, phosphite antioxidant, thioether meter antioxidant, melamine A flame retardant etc. can be used. Among these, it is particularly preferable to use one or more selected from the group consisting of phosphorus antioxidants, hindered phenol antioxidants, and amine antioxidants. When the resin composition (pellet P, resin structure S) contains these antioxidants, the resin composition can prevent deterioration (oxidation) of the cured thermosetting resin more reliably. The heat resistance of the obtained fiber reinforced resin cured product can be further improved.

  Examples of phosphorus antioxidants include melamine polyphosphate, bis- (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, and tris (2,4-di-t-butylphenyl). Phosphite), tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester , Bis- (2,6-dicumylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tris (mixed mono-nonylphenyl phosphite) , Tris (mixed di-nonylphenyl phosphite), bis (2,4-di-t-butylphenyl) penta Rithritol di-phosphite, bis (2,6-di-t-butyl-4-methoxycarbonylethyl-phenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-octadecyloxycarbonyl) And ethyl-phenyl) pentaerythritol diphosphite.

  Examples of the hindered phenol antioxidant include pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} 2,4,8,10-tetraoxaspiro [5,5] undecane, octadecyl-3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3 , 5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,6-di-tert-butyl-4-methylpheno 2,6-di-t-butyl-4-ethylphenol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-di-t-butyl-4-hydroxyphenyl) propionate, di Stearyl (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate, thiodiethylene glycol bis [(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 4,4′-thiobis (6 -T-butyl-m-cresol), 2-octylthio-4,6-di (3,5-di-t-butyl-4-hydroxyphenoxy) -s-triazine, 2,2'-methylenebis (4-methyl) -6-tert-butyl-6-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), bis [3,3-bis ( -Hydroxy-3-t-butylphenyl) butyric acid] glycol ester, 4,4'-butylidenebis (6-t-butyl-m-cresol), 2,2'-ethylidenebis (4,6-di-t -Butylphenol), 2,2'-ethylidenebis (4-s-butyl-6-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, Bis [2-t-butyl-4-methyl-6- (2-hydroxy-3-t-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3- Hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris [(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, tetrakis [methylene-3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionate] methane, 2-t-butyl-4-methyl-6- (2-acryloyloxy-3-t-butyl-5-methylbenzyl) phenol, 3,9-bis (1,1-dimethyl- 2-Hydroxyethyl) -2,4-8,10-tetraoxaspiro [5,5] undecane-bis [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], triethylene glycol Bis [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 2,2′-methylenebis (4-methyl-6-tert-butyl) Ruphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis (2- (3 -T-butyl-4-hydroxy-5-methylphenylpropionyloxy) 1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5,5) undecane, 4,4'-thiobis (3 -Methyl-6-t-butylphenol), 4,4'-bis (3,5-di-t-butyl-4-hydroxybenzyl) sulfide, 4,4'-thiobis (6-t-butyl-2-methyl) Phenol), 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl)- 4 Methylphenyl acrylate.

  Examples of amine-based antioxidants include p, p'-dioctyldiphenylamine, phenyl-α-naphthylamine, and phenothiazine.

In the resin composition of the present embodiment, one or more of the above-described antioxidants can be used in combination.
Among these, at least one selected from the group consisting of phosphorus antioxidants and hindered phenol antioxidants is preferable, and it is more preferable to use at least a phosphorus antioxidant.

  The content of the specific antioxidant in the resin composition of the present embodiment is preferably 0.01% by mass or more and 20% by mass or less of the total amount (100% by mass) of the resin composition. The content is more preferably from 05% by mass to 10% by mass, and further preferably from 1% by mass to 5% by mass. When the content of the antioxidant is equal to or higher than the lower limit, it becomes easy to improve the heat resistance of the cured fiber reinforced resin. It becomes easy to increase the wearing strength.

  Examples of the resin other than the thermosetting resin include curable resins such as a photocurable resin, a radical reactive curable resin, and an anaerobic curable resin.

  As described above, the resol type phenolic resin has a self-reactive functional group (such as a methylol group) and can be cured as it is by heating. Accordingly, a curing agent is not necessarily required, but a curing agent can be appropriately selected and used according to the type of resin used in combination.

  For example, when a phenol resin is used as the resin, the curing agent can be selected from bifunctional or higher epoxy compounds, isocyanates, hexamethylenetetramine, and the like.

  When an epoxy resin is used as the resin, the curing agent includes amine compounds such as aliphatic polyamines, aromatic polyamines and diciamine diamides, acid anhydrides such as alicyclic acid anhydrides and aromatic acid anhydrides, and novolaks. It can be selected from polyphenol compounds such as type phenol resins, imidazole compounds and the like. Among these, it is preferable to select a novolac-type phenol resin as a curing agent from the viewpoint of handling workability and environment.

  In particular, when one of a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, or a tris (hydroxyphenyl) methane type epoxy resin is used as an epoxy resin, a novolac type phenol resin may be selected and used as a curing agent. preferable. Thereby, the heat resistance of the fiber reinforced resin cured product can be improved.

  When using a hardening | curing agent, the content rate of the hardening | curing agent in the resin composition of this embodiment is 0.1 to 30 mass% of the total amount (100 mass%) of a resin composition, for example. It is preferable. Thereby, the fiber reinforced resin cured product can be easily formed into an arbitrary shape.

In addition, the curing aid is not particularly limited, and for example, a metal oxide compound such as magnesium oxide; a metal hydroxide compound such as calcium hydroxide; an imidazole compound, a tertiary amine compound, an organic phosphorus compound, and the like can be used. .
Among these, a metal hydroxide compound is preferable because the curability of the resol type phenol resin can be easily increased.

  When using a curing aid, the content of the curing aid in the resin composition of the present embodiment is, for example, 0.001% by mass or more and 10% by mass or less of the total amount (100% by mass) of the resin composition. Is preferred. Thereby, since a resin composition can be hardened more easily, a fiber reinforced resin hardened | cured material can be shape | molded more easily.

Further, the filler is not particularly limited, and examples thereof include inorganic fillers and organic fillers. Examples of the inorganic filler include calcium carbonate, clay, silica, mica, talc, wollastonite, glass beads, milled carbon, graphite, and the like, and one or more of these may be used in combination. Can do. Examples of the organic filler include polyvinyl butyral, acrylonitrile butadiene rubber, pulp, wood powder, and the like, and one or more of these can be used in combination.
Among these, it is particularly preferable to use clay as a filler (inorganic filler) from the viewpoint of improving the heat resistance of the cured resin.

  When using the filler, the content of the filler in the resin composition of the present embodiment is not particularly limited, but is 1% by mass to 30% by mass of the total amount (100% by mass) of the resin composition. Preferably there is. Thereby, the mechanical strength of the resin cured product can be further improved.

  Moreover, when an antioxidant is included in the resin composition and an inorganic filler is included as a filler, the ratio of the antioxidant to the inorganic filler is as a mass ratio represented by the inorganic filler / antioxidant. The range of 1 to 10 is preferable, and the range of 2 to 8 is more preferable. When the mass ratio is within the above preferable range, the mechanical strength of the resin cured product is increased and the heat resistance is easily improved.

Moreover, it does not specifically limit as a mold release agent, For example, a zinc stearate, a calcium stearate, etc. can be used.
When a release agent is used, the content of the release agent in the resin composition of the present embodiment is not particularly limited, but is 0.01% by mass or more of the total amount (100% by mass) of the resin composition. It is preferable that it is 0.0 mass% or less. Accordingly, the cured resin can be more easily formed into an arbitrary shape.

  Among the above-described resin compositions (pellets P, resin structures S) of the present embodiment, a fiber-reinforced resin cured product in which mechanical strength is further enhanced and heat resistance is further improved is easily obtained. The resin structure S is preferable.

  In the resin structure S of the present embodiment, at least one of the average density and the average bulk density, preferably both have a required range.

The average density of the resin structure S is more be preferably in the range of 0.20~1.00 (g / cm ^3), in the range of 0.30~0.80 (g / cm ³⁾ preferable.
In addition, the average density of the resin structure S can be measured according to the density and specific gravity measurement method by the geometric measurement specified in “JIS Z8807”.

Average bulk density in the resin structure S is preferably in the range of 0.15~0.60 (g / cm ^3), in the range of 0.20~0.50 (g / cm ³⁾ More preferred.
The average bulk density of the resin structure S can be measured using a general powder property evaluation apparatus (such as “Powder Tester PT-X” manufactured by Hosokawa Micron Corporation). Specifically, for example, a 100 (cm ³ ) container can be freely dropped through a chute, the weight can be measured without tapping, and the weight can be obtained by dividing the weight by the volume of the container.

  The resin structure S of the present embodiment holds the fibers opened in the thermosetting resin in a sufficiently dispersed state by having at least one of the average density and the average bulk density in the numerical range described above. can do. Thereby, when the resin structure S is used as a raw material for compression molding, the mechanical strength is further increased, and it becomes possible to produce a fiber reinforced resin cured product having excellent heat resistance.

The average particle diameter of the resin structure S of the present embodiment is preferably 2 mm or more and 15 mm or less, more preferably 3 mm or more and 12 mm or less, and further preferably 5 mm or more and 10 mm or less. If the average particle diameter of the resin structure S is within the above preferred range, it is easy to measure when molding the cured resin by compression molding and can be suitably used as a raw material.
In addition, the average particle diameter of the resin structure S can be calculated | required by the screening test method of JISZ8815. Further, the average particle diameter is the particle diameter (median diameter in the cumulative distribution) at an integrated value of 50% in the particle size distribution.

  In the resin structure S of the present embodiment, the fiber area fraction is preferably in the range of 10 to 40%, more preferably in the range of 15 to 30%, and more preferably in the range of 20 to 20% when viewed in cross section. More preferably, it is in the range of 30%. When the area fraction of the fiber when the resin structure S is viewed in a cross section is within the above preferable range, it can be confirmed that the opened fiber is held in a dispersed state in the thermosetting resin.

  In particular, when the resin structure S of the present embodiment is a uniaxial extrusion granulated product as shown in FIG. 3 (described later), when viewed in cross section by a plane perpendicular to the axis (extrusion) direction of the columnar product, It is preferable that the area fraction of the fiber is in the preferable range described above. Thereby, since the quality of the resin structure S is stable, for example, when used as a raw material for compression molding or the like, it is possible to easily manufacture a cured fiber reinforced resin having excellent heat resistance.

  In addition, the measurement of the fiber area fraction when the resin structure S is viewed in cross-section can be measured using, for example, an X-ray CT apparatus (manufactured by Yamato Kagaku, “TDM1000-II” or the like). As a measurement method, specifically, for example, the area of the fiber can be extracted from a cross-sectional image measured by X-ray CT, and the area fraction can be obtained.

[Method for producing fiber-containing resin composition]
Next, a method for producing the resin composition (pellet P, resin structure S) of the present embodiment will be described.

Manufacturing method of pellet P:
As a method for producing the pellet P, for example, a powder impregnation method using roving can be used according to the description in JP-T-2002-509199.

  The powder impregnation method using roving is a method of coating fibers by a dry method using a fluidized bed technique. Specifically, first, a thermosetting resin containing a resol type phenol resin or the like is directly applied to the fiber from the fluidized bed. Next, the material such as the thermosetting resin is fixed to the fiber by heating for a short time. The thus coated fibers are then passed through a conditioning section consisting of a cooling device and optionally a heating device. Thereafter, the cooled and coated fiber is taken up and cut to a desired length by a strand cutter. Thereby, the pellet P as shown in FIG. 1 is obtained.

Manufacturing method of resin structure S:
As will be described later, the resin structure S is a forced granulated material that is mechanically granulated using a screw, a nozzle, or the like. Specifically, an extruded granulated product that is granulated by extrusion granulation is preferable. More specifically, it is more preferably a uniaxial extrusion granulated product such as a substantially columnar shape (substantially cylindrical shape), a bowl shape, or a substantially spherical shape extruded from one or more discharge ports (openings) provided in the nozzle. . Moreover, since it can granulate without using a solvent when granulating, it is one of the preferable aspects to granulate without using a solvent.

First embodiment:
FIG. 3 is a schematic diagram for explaining an embodiment of a method for producing the resin structure S.
In FIG. 3, the manufacturing method of the resin structure S includes a step of preparing a pellet in which a bundle of fibers is hardened with a thermosetting resin containing a resol type phenol resin (preparation step), and the pellet is heated and melted. A step of obtaining a molten mixture in which fibers are dispersed in a state of being opened in a thermosetting resin (first step 1-1), and discharging the molten mixture from a discharge port, and then expanding the expanded molten mixture to a size suitable for molding. And a step of separating from the discharge port (step 1-2).

"Preparation process"
In the preparation step, pellets used as raw materials when the resin structure S is manufactured are prepared. Specifically, the above-described pellet P as shown in FIG. 1 is prepared by solidifying a bundle of long fibers with a thermosetting resin containing a resol type phenol resin. Here, the pellet P is roughly configured to include the thermosetting resin including the above-described resol type phenol resin, fibers, and other components.
The thermosetting resin containing the resol type phenol resin applied to the resin structure S may be in any form such as solid, liquid, and semisolid at room temperature. In addition, it is preferable that it is solid when using as the resin structure S from a viewpoint of the handleability at the time of measurement.

"Step 1-1"
In the 1-1st step, the pellet P produced in the preparation step is heated to melt the thermosetting resin containing the resol type phenolic resin, and the fibers are dispersed in the opened state in the molten thermosetting resin. A molten mixture is obtained. As shown in FIG. 3, the fiber bundle contained in the pellet P is opened and the fibers are dispersed by melt mixing using the injection unit 10 of the injection molding machine.

  As shown in FIG. 3, the injection unit 10 of the injection molding machine includes a cylinder 11, a nozzle 12 provided at the tip of the cylinder 11, a screw 13 that can rotate within the cylinder 11, and the cylinder 11 and the screw 13. It is schematically configured to include an inlet 14 for feeding pellets P into the space between them and a heater 15 for heating the pellets P via the cylinder 11. The screw 13 is movable in the axial direction of the cylinder 11.

  Specifically, first, as shown in FIG. 3, the pellets P are supplied from the inlet 14 to the injection unit 10 of the injection molding machine being heated. In the supplied pellet P, the thermosetting resin melts in the cylinder 11. At this time, the temperature in the cylinder 11 is preferably in the range of 70 to 140 (° C.), and more preferably in the range of 80 to 130 (° C.). The fiber is opened by a shearing force generated by the rotation of the screw 13. Thereby, a molten mixture in which the spread fibers are dispersed in the molten thermosetting resin is obtained. At that time, with the nozzle 12 diameter reduced or the nozzle 12 port closed, the screw 13 is rotated to melt and mix the pellet P, so that the screw 13 moves backward toward the inlet 14 opposite to the nozzle 12. At the same time, the molten mixture that has been sent forward by the rotation of the screw 13 and accumulated is measured.

  Here, the screw peripheral speed is preferably in the range of 16 to 340 (mm / sec) and more preferably in the range of 30 to 250 (mm / sec) in the injection unit 10 of the injection molding machine. . Furthermore, the temperature of the extruded molten mixture is preferably in the range of 70 to 140 (° C), more preferably in the range of 80 to 130 (° C). By setting the screw peripheral speed and temperature within the above preferred ranges, the fiber bundle can be effectively opened and dispersed in the melted thermosetting resin.

  Moreover, it does not specifically limit as a diameter of the discharge outlet 12a, According to the magnitude | size of the desired resin structure S, it can select suitably. Specifically, the diameter of the discharge port 12a is preferably in the range of 3 to 20 (mm), and more preferably in the range of 5 to 12 (mm). It is preferable to use the above preferable range because, for example, measurement becomes easy when used as a raw material for compression molding or the like.

"Step 1-2"
Next, in the 1-2 process, the nozzle 12 is opened and the screw 13 is advanced to discharge the molten mixture from the discharge port 12a.
The molten mixture (resin composition) discharged from the discharge port 12a expands, and the expanded molten mixture is separated from the discharge port 12a so as to have a size suitable for molding.
Here, the expansion range is preferably more than 100% and 250% or less, more preferably 110% or more and 220% or less, and more preferably 120% or more and 200% or less with respect to the diameter of the discharge port 12a. More preferably it is. By inflating until it becomes the said range, as shown in FIG. 3, the resin structure S of this embodiment is obtained.

  In addition, when the molten mixture (resin composition) after expansion is separated from the discharge port 12a, it may be recovered as a granular resin structure S by separation immediately after expansion. Moreover, after discharging from the discharge port 12a and expanding, it may be cut off from the discharge port 12a when it becomes a certain length, and then cut at a desired interval to form a granular resin structure S.

  Moreover, in the manufacturing method of the resin structure S, the fiber bundles are opened, but breakage occurs, so the fiber length in the resin structure S is shortened. Therefore, it is preferable to use pellets containing fibers longer than the length of fibers required in the resin structure S (average length of 1 to 20 mm) in the pellets P to be fed into the injection unit 10 of the injection molding machine as a raw material.

  In addition, the fiber length after opening using the injection unit 10 of the injection molding machine also varies depending on the shape of the screw 13, the shape of the nozzle 12, and the like. Therefore, it is preferable to select and use a shape suitable for preventing fiber breakage.

  According to the method for producing the resin structure S shown in FIG. 3, the injection unit 10 of the injection molding machine is used to obtain a molten mixture in which fibers are dispersed in the opened state in the molten thermosetting resin. By discharging the molten mixture from the discharge port 12a and expanding the molten mixture after being discharged from the discharge port 12a to a required range with respect to the diameter of the discharge port 12a, then separating from the discharge port 12a, The resin structure S can be easily manufactured.

In the first embodiment described above with respect to the method of manufacturing the resin structure S shown in FIG. 3, after the pellets P are melt-kneaded and measured by the rotation of the screw 13, the molten mixture (resin Although the method of discharging and separating the composition) from the discharge port 12a has been described, the present invention is not limited to this.
For example, a method may be used in which the molten mixture is discharged and discharged from the discharge port 12a while the pellet P is melt-mixed by rotation of the screw 13 in the cylinder 11. In the case of this method, by rotating the screw 13 with the nozzle 12 having a large diameter and the nozzle 12 opening being opened, the pellet P is melted and mixed, and the stress in the direction of the nozzle 12 is applied to the molten mixture. Accordingly, the molten mixture is gradually discharged from the discharge port 12a.

Second embodiment:
FIG. 4 is a schematic diagram for explaining another embodiment (second embodiment) of the method of manufacturing the resin structure S. In FIG. 4, the manufacturing method of the resin structure S is roughly comprised including a preparatory process and a 2nd process. Regarding the second embodiment, the description common to the above-described first embodiment is omitted.

"Preparation process"
The description of the preparation process is the same as the preparation process in the first embodiment. The pellet P is produced by this preparation process.

"Second step"
In the second step, the pellet P produced in the preparation step is heated to melt the thermosetting resin, and while obtaining the molten mixture in which the fibers are dispersed in the opened state in the molten thermosetting resin, The molten mixture is extruded and separated from a plurality of discharge ports 22a provided at the tip.

  As shown in FIG. 4, the fiber bundles contained in the pellets P are opened as in the injection unit 10 of the injection molding machine in the first embodiment described above by melt-mixing using the single-screw extruder 20. And promote fiber dispersion.

As shown in FIG. 4, the single-screw extruder 20 includes a cylindrical barrel 21 having a heating mechanism, a die 22 provided at the tip of the barrel 21, a screw 23 that can rotate within the barrel 21, An introduction port 24 for introducing pellets P as raw materials for resin and fibers into the space between the barrel 21 and the screw 23 is schematically configured.
The dice 21 are provided with a plurality of discharge ports 22a. When the dice 22 is viewed in plan, the discharge ports 22a are arranged at equal intervals in the circumferential direction. Furthermore, the temperature of the barrel 21 is provided with a temperature gradient such that the inlet 24 side is at a low temperature and the tip end side where the die 22 is provided is at a high temperature.

Specifically, first, as shown in FIG. 4, the pellets P are supplied from the charging port 24 to the heated barrel 21. In the supplied pellet P, the thermosetting resin melts in the barrel 21. The fiber is opened by a shearing force generated by the rotation of the screw 23. As a result, a molten mixture in which the spread fibers are dispersed in the molten thermosetting resin is obtained.
In addition, when the screw 23 rotates in the barrel 21, stress is applied to the molten mixture in the direction of the die 22, and the molten mixture is gradually discharged from each discharge port 22 a provided at the tip of the die 22. Become.

  Here, as a screw peripheral speed, it is preferable to set it as the range of 20-400 (mm / sec) in the single screw extruder 20, and it is more preferable to set it as the range of 40-300 (mm / sec). Furthermore, the temperature of the extruded molten mixture is preferably in the range of 70 to 140 (° C), more preferably in the range of 80 to 130 (° C). By setting the screw peripheral speed and temperature within the above preferred ranges, fiber bundle opening and fiber dispersion can be effectively performed in the molten thermosetting resin.

  Moreover, it does not specifically limit as a diameter of each discharge port 22a, According to the magnitude | size of the desired resin structure S, it can select suitably. Specifically, the diameter of the discharge port 22a is preferably in the range of 3 to 15 (mm), and more preferably in the range of 5 to 12 (mm). The above preferable range is preferable because, for example, measurement is facilitated when used as a raw material for compression molding.

  Next, the molten mixture (resin composition) discharged from the discharge port 22a expands, and the expanded molten mixture is separated from the discharge port 22a so as to have a size suitable for molding. Here, the expansion range is preferably more than 100% and 250% or less, more preferably 110% or more and 220% or less, and further preferably 120% or more and 200% or less. By inflating until it becomes the said range, as shown in FIG. 4, the resin structure S of this embodiment is obtained.

  In the second embodiment as well, as in the first embodiment described above, when the molten mixture (resin composition) after expansion is separated from the discharge port 22a, the granular mixture is separated immediately after expansion. The resin structure S may be recovered. Moreover, after discharging from the discharge port 22a and expanding, it may be cut off from the discharge port 22a when it reaches a certain length, and then cut at a desired interval to form a granular resin structure S.

  Moreover, in the manufacturing method of the resin structure S, the fiber bundles are opened, but breakage occurs, so the fiber length in the resin structure S is shortened. Therefore, it is preferable to use pellets containing fibers longer than the length of fibers required in the resin structure S (average length of 1 to 20 mm) in the pellets P to be fed into the single screw extruder 20 as a raw material.

  The fiber length after opening using the single screw extruder 20 also varies depending on the shape of the screw 23, the shape of the discharge port 22a provided in the die 22, and the like. Therefore, it is preferable to select and use a shape suitable for preventing fiber breakage.

  According to the method for producing the resin structure S shown in FIG. 4, a single-screw extruder 20 is used to obtain a melt mixture in which fibers are dispersed in a melted thermosetting resin, and the melt By discharging the mixture from the plurality of discharge ports 22a, and separating from the discharge ports 22a after expanding until the diameter of the molten mixture after being discharged from the discharge ports 22a is within a required range with respect to the diameter of the discharge ports 22a, The resin structure S can be manufactured more efficiently.

  In the manufacturing method of the resin structure S of the second embodiment described above, the case where the single screw extruder 20 is used has been described as an example of the extruder, but is not limited thereto. For example, the resin structure S may be manufactured using a biaxial or more extruder. The configuration of the single screw extruder 20 shown in FIG. 4 is an example, and the shape of the screw 23, the shape of the discharge port 22a provided in the die 22, and the like are not particularly limited.

  In the manufacturing method of the resin structure S of the first and second embodiments described above, the raw material (thermosetting resin including resol type phenol resin, fiber) is supplied to the injection unit 10 or the single screw extruder 20 of the injection molding machine. Although the case where the pellet P was used as an aspect to supply was demonstrated as an example, it is not limited to this. For example, an aggregate obtained by further solidifying the pellets P may be used, or the thermosetting resin and the fibers may be charged separately. Moreover, when using the pellet P, you may manufacture the desired resin structure S by adding thermosetting resin and a fiber additionally.

(Hardened fiber reinforced resin)
The characteristics of the cured fiber reinforced resin obtained by curing the pellet P of this embodiment will be described.
The cured fiber reinforced resin obtained by curing the pellet P (untreated state after preparation) preferably has a bending strength indicating mechanical strength of 100 MPa or more, more preferably 110 to 140 MPa.
Moreover, the fiber reinforced resin cured product obtained by curing the pellet P has a bending strength of preferably 50 MPa or more, more preferably 60 to 90 MPa, for example, after being heated at 280 ° C. for 250 hours. Improvements are being made.

The fiber reinforced resin cured product obtained by curing the pellet P (after preparation, in an untreated state) has a flexural modulus indicating mechanical strength of preferably 12 GPa or more, more preferably 13 to 18 GPa, and mechanical strength has been conventional. Is higher than.
The cured fiber reinforced resin obtained by curing the pellet P has a flexural modulus after heating at 280 ° C. for 250 hours, for example, preferably 5 GPa or more, more preferably 6 to 10 GPa. Improvements are being made.

Next, the characteristics of the fiber reinforced resin cured product obtained by curing the resin structure S of the present embodiment will be described.
The fiber reinforced resin cured product obtained by curing the resin structure S (after preparation, in an untreated state) has a bending strength indicating mechanical strength of preferably 110 MPa or more, more preferably 120 to 170 MPa, and mechanical strength. Is higher than before.
In addition, the fiber reinforced resin cured product obtained by curing the resin structure S has a bending strength of, for example, 40 MPa or more, more preferably 50 to 70 MPa, after being heated at 280 ° C. for 250 hours, which is more heat resistant than conventional ones. The improvement of the property is aimed at.

The fiber reinforced resin cured product obtained by curing the resin structure S (unprocessed after preparation) has a flexural modulus indicating mechanical strength of preferably 14 GPa or more, more preferably 15 to 20 GPa, and mechanical strength. Is higher than before.
Further, the cured fiber reinforced resin obtained by curing the resin structure S has a flexural modulus after heating at 280 ° C. for 250 hours, for example, preferably 6 GPa or more, more preferably 8 to 12 GPa. The improvement of the property is aimed at.

  Here, evaluation of the mechanical strength in the fiber reinforced resin cured product is performed by measuring the bending strength and the bending elastic modulus by a method based on ISO 178, respectively.

  The cured fiber reinforced resin obtained by curing the resin structure S may have a fractal value (fractal dimension (D) value) indicating a dispersion state of fibers in the thermosetting resin of more than 0.30 and 1.0 or less. Preferably, it is 0.31 or more and 0.9 or less. When the fractal value is within the above preferred range, there are few unopened fibers, indicating that the fibers are not unevenly distributed in the thermosetting resin, and the state of fiber opening and dispersion in the thermosetting resin Can be evaluated as good.

  The fiber reinforced resin cured product obtained by curing the resin structure S preferably has a standard deviation of the orientation tensor value indicating the orientation state of the fiber in the thermosetting resin of 0.01 or more and 0.22 or less. More preferably, it is 0.05 or more and 0.20 or less. When the standard deviation of the orientation tensor value is within the above preferable range, the orientation of the fibers tends to be closer to the random orientation, and it can be evaluated that the dispersion state of the fibers in the thermosetting resin is good.

  Here, the evaluation of the dispersion state and orientation state of the fiber in the fiber reinforced resin cured product is performed by taking an X-ray of the target cured product from various directions and performing reconstruction processing by a computer (Computed Tomography). ; Calculated from data measured using computed tomography). Thereby, the hardened | cured material used as object can be evaluated nondestructively. As the X-ray inspection apparatus, for example, “TDM1000-II” manufactured by Yamato Kagaku can be used.

Specifically, the fractal dimension (D) value for evaluating the dispersion state of the fibers in the thermosetting resin is calculated by the following procedures (11) to (14).
Procedure (11) First, a two-dimensional image obtained from data measured using X-ray CT is binarized.
Procedure (12) Next, the entire two-dimensional image is divided so that each of the X direction and the Y direction is divided into n equal parts (6 ≦ n ≦ 82). This divides the entire image into n ² boxes.
Procedure (13) Next, the fiber area ratio in each box is calculated at each n value, and the coefficient of variation (C _v (n) = is calculated from the average value (a) and the standard deviation (σ) of the fiber area ratio. σ / a) is calculated.
Procedure (14) Next, each n value is plotted in a log-log graph in which the x axis is the reciprocal of the n value “1 / n” and the y axis is the coefficient of variation “C _v (n)”, and the obtained approximation A value obtained by multiplying the slope of the straight line by “−1” is defined as a fractal dimension (D) value.
It can be evaluated that the higher the fractal dimension (D) value, the higher the dispersibility of the fibers in the thermosetting resin and the better the opened state.

The standard deviation of the orientation tensor value for evaluating the orientation state of the fibers in the thermosetting resin is specifically calculated by the following procedures (21) to (24).
Procedure (21) First, a three-dimensional model is reconstructed from data measured using X-ray CT.
Procedure (22) For the three-dimensional model, the fiber and the resin are binarized and separated.
Procedure (23) The fiber direction tensor (Txx, Tyy, Tzz) is calculated. Txx, Tyy, and Tzz indicate alignment tensors in the X-axis, Y-axis, and Z-axis directions, respectively. Further, Txx + Tyy + Tzz = 1. When each orientation tensor value is 0.33, it can be evaluated that the orientation is random.
Procedure (24) The standard deviation is calculated from Txx, Tyy, Tzz whose total number of data in the analysis range is about 2000.

  Such a fiber reinforced resin cured product is a cured product produced using the resin structure S as a molding material, as described above, and a fractal value indicating the dispersion state of fibers in the thermosetting resin, and the thermosetting resin. Since the standard deviation of the orientation tensor value indicating the orientation state of the fibers inside is within the required range, the mechanical strength can be further increased. Moreover, this resin cured product is excellent in heat resistance.

Next, an example of a method for producing a cured fiber reinforced resin will be described.
Such a fiber reinforced resin cured product is commonly used by using a resin composition (pellet P, resin structure S) containing a thermosetting resin containing a resol type phenolic resin and a specific length of fiber as a molding material. It can be manufactured by compression molding or the like.
Specifically, first, a resin composition that is a molding material is preheated. As preheating, a hot-air circulating dryer or an infrared heater is also used, but high-frequency preheating is most effective. It is preferable to select appropriately according to the kind and amount of the thermosetting resin used.

Next, after a required amount of the resin composition is weighed and charged into the cavity of the mold, a low pressure (for example, about 5 MPa) is gradually applied to soften and flow the material. Immediately before or after completion of mold clamping, the pressure is once released (gas venting operation), and then immediately after high pressure (for example, molding pressure of about 15 to 40 MPa) is applied, the mold is closed and cured for a predetermined time.
After curing, the molded article is removed from the mold to obtain a cured fiber reinforced resin.

  If effective preheating is performed by high frequency preheating, the above-described degassing operation can be omitted. In addition, the polycondensation-type resin molding material requires a degassing operation, but the addition polycondensation-type resin molding material generally does not need to be degassed.

  In addition, molding conditions such as molding pressure, molding temperature, and curing time are preferably selected as appropriate according to the resin composition that is the molding material. For example, the molding pressure at high pressure can be about 20 to 50 MPa, the molding temperature can be about 150 to 200 ° C., and the curing time can be about 1 to 10 minutes.

  As described above, according to the resin composition (pellet P, resin structure S) of the present embodiment, both the thermosetting resin including the resol type phenol resin and the fiber having a specific length are included. The mechanical strength of the cured fiber reinforced resin produced using this can be further increased, and the heat resistance can be increased.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first and second embodiments described above, the case where the cured product or the like using the resin structure S is manufactured has been described as an example in which it is applied to general compression molding, but the present invention is not limited to this. For example, it may be applied to transfer molding and injection molding, or may be applied in combination with each molding method such as transfer-compression molding and injection-compression molding.

  Moreover, in the fiber containing resin composition mentioned above, although the pellet P shown in FIG. 1 and the resin structure S shown in FIG. 2 were demonstrated, it is not limited to this. The shape of the resin composition is, for example, a tablet (tablet) shape, a strip shape, a columnar shape, an elliptical columnar shape, a prismatic shape, a lens shape, or a shape close to a product shape (for example, a shape close to a projected shape from above). And so on. The resin composition can be suitably used as a raw material for compression molding, transfer molding, transfer-compression molding, or the like by having any predetermined shape.

For example, in the case of a resin composition (resin structure T) having a tablet (tablet) shape, the thickness of the resin structure T is not particularly limited, and can be 1 mm or more and 300 mm or less, preferably 2 mm or more and 200 mm or less. is there.
In addition, the thickness direction of the resin structure T is a pressing direction at the time of pressure molding. For structures with a distribution of thickness, such as a lens shape, this means the thickness of the largest part, and after shaping the tablet shape, it is also necessary to reshape it into another shape such as a roughly spherical shape or a football shape. Can be implemented according to

Third embodiment:
FIG. 5 is a schematic view for explaining an embodiment of a method for producing a resin composition having a tablet (tablet) shape, that is, a resin structure T.
In FIG. 5, the manufacturing method of the resin structure T includes a step of preparing pellets in which a bundle of fibers is hardened with a thermosetting resin containing a resol type phenol resin (preparation step), while melting and mixing the pellets. A step of supplying the molten mixture into a mold recess (cavity) while maintaining a molten state (step 3-1), and a step of producing a resin structure T having a desired shape while applying pressure (third step) 2 steps). Regarding the third embodiment, the description common to the first embodiment described above is omitted.

"Preparation process"
The description of the preparation process is the same as the preparation process in the first embodiment. The pellet P is produced by this preparation process.

"Step 3-1"
In step 3-1, the pellet P produced in the preparation step is heated to melt the thermosetting resin containing the resol type phenolic resin, and the fibers are dispersed in the opened state in the molten thermosetting resin. While obtaining the molten mixture, the molten mixture is extruded from the discharge port 12a provided at the tip of the nozzle 12 into the mold (that is, into the cavity) of the preforming machine 30 for tablet molding.

  As shown in FIG. 5, the fiber bundle contained in the pellet P is opened and the fibers are dispersed by melting and mixing using the injection unit 10 of the injection molding machine, as in the first embodiment described above. And promote.

  In FIG. 5, an injection unit 10 of the injection molding machine includes a cylinder 11, a nozzle 12 provided at the tip of the cylinder 11, a screw 13 that can rotate within the cylinder 11, and a space between the cylinder 11 and the screw 13. And a heater 15 that heats the pellet P via the cylinder 11 and is schematically configured. The screw 13 is movable in the axial direction of the cylinder 11.

Specifically, first, as shown in FIG. 5, the pellets P are supplied from the inlet 14 to the injection unit 10 of the heated injection molding machine. In the supplied pellet P, the thermosetting resin melts in the cylinder 11. The fiber is opened by a shearing force generated by the rotation of the screw 13. Thereby, a molten mixture in which the spread fibers are dispersed in the molten thermosetting resin is obtained.
Further, when the screw 13 rotates in the cylinder 11, the molten mixture is pushed out from the discharge port 12a provided at the tip of the nozzle 12 into the mold (that is, inside the cavity 30a) of the preforming machine 30 for tablet molding. . Specifically, when the screw 13 rotates in the cylinder 11, a stress is applied to the molten mixture in the direction of the nozzle 12, and the molten mixture is gradually discharged from the discharge port 12a into the cavity 30a of the preforming machine 30. Will be.

  As shown in FIG. 5, the preforming machine 30 is provided so as to be connected to the injection unit 10 of the injection molding machine, and a discharge port 12a provided at the tip of the nozzle 12 of the injection unit 10 of the injection molding machine is provided. It is comprised so that it may open to the cavity 30a of the preforming machine 30. Thereby, the molten mixture discharged from the discharge port 12a can be supplied into the mold recess (cavity) 30a while maintaining the molten state.

  Here, the screw peripheral speed is preferably in the range of 16 to 340 (mm / sec) and more preferably in the range of 30 to 250 (mm / sec) in the injection unit 10 of the injection molding machine. . Furthermore, the temperature of the extruded molten mixture is preferably in the range of 70 to 140 (° C), more preferably in the range of 80 to 130 (° C). By setting the screw peripheral speed and temperature within the above preferred ranges, fiber bundle opening and fiber dispersion can be effectively performed in the molten thermosetting resin.

  The diameter of the discharge port 12a is not particularly limited and can be appropriately selected. Specifically, the diameter of the discharge port 12a is preferably in the range of 3 to 40 (mm), and more preferably in the range of 5 to 30 (mm). The above preferable range is preferable because discharge into the cavity 30a is facilitated.

  Next, the molten mixture is weighed (weighed) using the preforming machine 30. Specifically, for example, by measuring a change in weight when the molten mixture discharged from the discharge port 12a is supplied into the cavity 30a of the mold, a required amount of the molten mixture is supplied into the cavity 30a. Next, after a required amount of the molten mixture is weighed, the supply of the molten mixture from the injection unit 10 of the injection molding machine is stopped.

  Moreover, in the manufacturing method of the resin structure T, the fiber bundles are opened, but breakage occurs, so the fiber length in the resin structure T is shortened. Therefore, it is preferable to use pellets containing fibers longer than the length of fibers required in the resin structure T (average length of 1 to 20 mm) in the pellets P to be fed into the injection unit 10 of the injection molding machine as a raw material.

  In addition, the fiber length after opening using the injection unit 10 of the injection molding machine also varies depending on the shape of the screw 13, the shape of the nozzle 12, and the like. Therefore, it is preferable to select and use a shape suitable for preventing fiber breakage.

"Step 3-2"
Next, a resin structure T having a desired shape is produced while applying pressure to the molten mixture extruded into the mold (in the cavity). At this time, the preformed machine 30 is preferably shaped by pressurizing the weighed molten mixture in a soft state before cooling. Usually, since the tableting is performed in a melted state, it is not necessary to heat the mold or the molten mixture, but it may be cooled or heated to a required temperature as necessary.

The temperature of the molten mixture at the time of shaping is not particularly limited as long as the softness capable of tableting is maintained.
The pressure at the time of shaping is not particularly limited as long as it can be shaped into a required shape. Specifically, it can be set to 1 MPa or more and 30 MPa or less, and preferably 2 MPa or more and 20 MPa or less. Thereby, while containing a required amount of thermosetting resin and fiber, the resin structure T which has the shape of a tablet can be manufactured.

According to the method for producing the resin structure T shown in FIG. 5, the injection unit 10 of the injection molding machine is used to obtain a molten mixture in which fibers are dispersed in a state of being opened in a molten thermosetting resin, The resin structure T can be easily manufactured by supplying the molten mixture into the cavity 30a of the mold (preliminary molding machine 30) while maintaining the molten state.
Moreover, according to the manufacturing method of the resin structure T, since the apparatus of the structure which the injection unit 10 of the injection molding machine and the preforming machine 30 are connected is used, the resin structure T is manufactured continuously. be able to.

  Further, by using a resin structure T having a tablet (tablet) shape as a molding material, it is convenient for preheating when producing a fiber reinforced resin cured product, and the resulting resin cured product has few burrs, The mold cavity 30a can be made shallow.

  In the manufacturing method of the resin structure T illustrated in FIG. 5, the case where the injection unit 10 of the injection molding machine is used as an example in the step 3-1 is not limited thereto. For example, the resin structure T may be manufactured using a single screw extruder, or may be manufactured using a twin screw extruder.

In the manufacturing method of the resin structure T, the case where the molten mixture is measured using the preforming machine 30 in the step 3-1 has been described as an example, but is not limited thereto.
For example, in the step 3-1, in the injection unit 10 of the injection molding machine, the pellet 13 is melt-mixed by rotating the screw 13 with the nozzle 12 port closed, as in the case of the step 1-1 described above. As a result, the screw 13 moves backward in the direction of the inlet 14 opposite to the nozzle 12, and the molten mixture sent forward and accumulated by the rotation of the screw 13 is measured. Thereafter, the required amount of the molten mixture is pushed out from the discharge port 12a into the cavity 30a of the preforming machine 30 by the advancement of the screw 13 in the direction of the nozzle 12. Thereby, a required amount of the molten mixture measured in the injection unit 10 of the injection molding machine can be supplied into the cavity 30a from the discharge port 12a of the nozzle 12.

  Moreover, in the manufacturing method of the resin structure T of embodiment mentioned above, although the structure which the injection unit 10 of the injection molding machine and the preforming machine 30 connected was demonstrated as an example, it is not limited to this. For example, after the molten mixture is weighed, the injection unit 10 of the injection molding machine and the preforming machine 30 may be separable. Thereby, since dispersion | distribution of the heat between the injection unit 10 of an injection molding machine and the preforming machine 30 can be suppressed, the production | generation of a molten mixture and the shaping | molding of the resin structure T can be performed efficiently. it can.

The fiber-containing resin composition to which the present invention is applied is a molding material suitable for, for example, compression molding, transfer molding, injection molding, or a combination of these. Such a fiber-containing resin composition can be used for various applications, and is particularly useful as a molding material for structural members.
In particular, the fiber-containing resin composition to which the present invention is applied is a molding material suitable for all uses requiring mechanical strength and heat resistance. Examples of such applications include brake pads or parts used in the engine room such as brackets or pulleys.
The resin composition (pellet P, resin structure S) of the above-described embodiment is preferably used as a material for molding a back plate in a brake pad including a friction material and a back plate joined to the friction material, for example. it can.

  Hereinafter, although the effect of the present invention is explained in detail using an example and a comparative example, the present invention is not limited to the following example.

<Preparation process: Preparation of pellets>
Pellets were prepared as follows. In addition, the mass% described about each component has shown the content rate in the pellet finally prepared.

(Preparation Example 1)
First, glass fiber (E glass, glass fiber roving 1084 manufactured by PPG, average diameter: 15 μm) surface-treated with a silane coupling agent was prepared as a fiber fibril.

  Next, 36.0% by mass of novolak-type phenolic resin (Sumilite Resin PR-51470 manufactured by Sumitomo Bakelite Co., Ltd., weight average molecular weight: 2800, phenol novolac resin) as a resin and 6.methylenetetramine as a curing agent. 0% by mass, 1.0% by mass of magnesium oxide as a curing aid, 1.0% by mass of calcium stearate as a mold release agent, and 1.0% by mass of carbon black as a pigment Thus, a resin mixture was obtained.

Next, using the fluidized bed technique, the obtained resin mixture is coated on the glass fiber so that the surface-treated glass fiber is 55% by mass, and the heater is heated to 400 ° C. Then, the mixture was melted and fixed, and then cooled.
Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

(Preparation Example 2)
9.0% by mass of novolac type phenolic resin (Sumilite Resin PR-51470, weight average molecular weight: 2800, phenol novolac resin, manufactured by Sumitomo Bakelite Co., Ltd.) as the resin, and resol type phenolic resin (Sumitomo Bakelite Co., Ltd.) as the resin PR-53529) 23.0% by mass, calcium hydroxide as a curing aid 1.0% by mass, calcium stearate as a mold release agent 1.0% by mass, and carbon black as a pigment 1.0% by mass was mixed to obtain a resin mixture.

Next, using the fluidized bed technique, the obtained resin mixture is coated on the glass fiber so that the surface-treated glass fiber is 65% by mass, and the heater is heated to 400 ° C. Then, the mixture was melted and fixed, and then cooled.
Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

(Preparation Example 3)
8.0% by mass of novolac type phenolic resin (Sumilite Resin PR-51470, weight average molecular weight: 2800, phenol novolac resin, manufactured by Sumitomo Bakelite Co., Ltd.) as a resin and resol type phenolic resin (Sumitomo Bakelite Co., Ltd.) PR-53529) 22.0% by mass, calcium hydroxide as a curing aid 1.0% by mass, melamine polyphosphate as an antioxidant 2.0% by mass, and as a release agent 1.0 mass% of calcium stearate and 1.0 mass% of carbon black as a pigment were mixed to obtain a resin mixture.

Next, using the fluidized bed technique, the obtained resin mixture is coated on the glass fiber so that the surface-treated glass fiber is 65% by mass, and the heater is heated to 400 ° C. Then, the mixture was melted and fixed, and then cooled.
Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

(Preparation Example 4)
5.0% by mass of novolac type phenolic resin (Sumilite Resin PR-51470, weight average molecular weight: 2800, phenol novolac resin, manufactured by Sumitomo Bakelite Co., Ltd.) as a resin, and resol type phenolic resin (Sumitomo Bakelite Co., Ltd., as a resin) PR-53529) 15.0% by mass, calcium hydroxide as a curing aid 1.0% by mass, melamine polyphosphate as an antioxidant 2.0% by mass, clay as a filler Was mixed with 10.0% by mass of calcium stearate as a release agent and 1.0% by mass of carbon black as a pigment to obtain a resin mixture.

Next, using the fluidized bed technique, the obtained resin mixture is coated on the glass fiber so that the surface-treated glass fiber is 65% by mass, and the heater is heated to 400 ° C. Then, the mixture was melted and fixed, and then cooled.
Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

(Preparation Example 5)
42.0% by mass of a resol type phenolic resin (PR-53529 manufactured by Sumitomo Bakelite Co., Ltd.) as a resin, 1.0% by mass of calcium hydroxide as a curing aid, and 1 calcium stearate as a mold release agent 0.0% by mass and 1.0% by mass of carbon black as a pigment were mixed to obtain a resin mixture.

Next, using the fluidized bed technique, the obtained resin mixture is coated on the glass fiber so that the surface-treated glass fiber is 55% by mass, and the heater is heated to 400 ° C. Then, the mixture was melted and fixed, and then cooled.
Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

(Preparation Example 6)
28% by mass of novolac-type phenolic resin (Sumilite Resin PR-51470 manufactured by Sumitomo Bakelite Co., Ltd., weight average molecular weight: 2800, phenol novolac resin) as resin, and 4.0% by mass of hexamethylenetetramine as curing agent A resin mixture obtained by mixing 1.0% by mass of magnesium oxide as a curing aid, 1.0% by mass of calcium stearate as a mold release agent, and 1.0% by mass of carbon black as a pigment. Got.

Next, using the fluidized bed technique, the obtained resin mixture is coated on the glass fiber so that the surface-treated glass fiber is 65% by mass, and the heater is heated to 400 ° C. Then, the mixture was melted and fixed, and then cooled.
Next, the glass fiber coated with the resin mixture was cut with a strand cutter so that fibers having an average length of 20 mm were obtained. Thereby, a pellet was obtained.

<Preparation of fiber-containing resin composition>
(Example 1)
When producing the fiber-containing resin composition of Example 1, the first embodiment described above was applied as a production method. That is, the pellets obtained in Preparation Example 2 were put into an injection unit of an injection molding machine, and the resin was melted by heating at 110 ° C., screw peripheral speed 70 mm / sec (diameter 32 mm: rotation speed 43 rpm) The fiber was opened to obtain a molten mixture.
Next, the obtained molten mixture is discharged from the discharge port (φ10 mm) at the tip of the nozzle of the injection unit of the injection molding machine and expanded from 110 to 200% with respect to the diameter of the discharge port, and then separated from the discharge port. Thus, the fiber-containing resin composition of Example 1 was obtained.

(Examples 2 to 4)
The fiber-containing resin compositions of Examples 2 to 4 were the same as Example 1 except that the pellets obtained in Preparation Example 2 were changed to the pellets obtained in Preparation Examples 3 to 5, respectively. I got each.

(Example 5)
The pellets obtained in Preparation Example 5 were used as they were as the fiber-containing resin composition of Example 5.

(Comparative Example 1)
The pellets obtained in Preparation Example 1 were used as they were as the fiber-containing resin composition of Comparative Example 1.

(Comparative Example 2)
A fiber-containing resin composition of Comparative Example 2 was obtained in the same manner as in Example 1 except that the pellet obtained in Preparation Example 2 was changed to the pellet obtained in Preparation Example 1.

(Comparative Example 3)
A fiber-containing resin composition of Comparative Example 3 was obtained in the same manner as in Example 1 except that the pellet obtained in Preparation Example 2 was changed to the pellet obtained in Preparation Example 6.

<Evaluation of pellet and fiber-containing resin composition>
The pellets obtained in Preparation Examples 1 to 6 and the fiber-containing resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated as follows. The evaluation results are shown in Table 1 below.

[Average density]
The average density of the pellets and the fiber-containing resin composition was measured according to a density and specific gravity measurement method based on geometric measurement defined in “JIS Z8807”.

[Average bulk density]
The average bulk density of the pellets and the fiber-containing resin composition was measured using a powder characteristic evaluation apparatus (manufactured by Hosokawa Micron Corporation, “Powder Tester PT-X type”, etc.). Specifically, a 100 (cm ³ ) container was used, it was dropped freely through a chute, the weight was measured without tapping, and the weight was obtained by dividing the weight by the volume of the container.

[Average fiber length (average fiber length)]
The average length (average fiber length) of the fibers contained in the pellets and the fiber-containing resin composition was calculated by the following procedures (1) to (3).
Procedure (1) The whole sample was heated at 550 ° C. using an electric furnace to vaporize the resin, and then only the fiber was taken out.
Procedure (2) The length of the fiber was measured using a microscope (number of fibers measured: 500 per sample).
Procedure (3) The weight average fiber length was calculated from the measured fiber length.

[Fiber area fraction]
When the pellet and the fiber-containing resin composition are viewed in cross section, the ratio of the fiber occupying the cross section (fiber area fraction) is measured using an X-ray CT apparatus (manufactured by Yamato Kagaku, “TDM1000-II”, etc.) Measured. Specifically, the area of the fiber occupying the cross section was extracted from the cross-sectional image measured by X-ray CT, and the area fraction was obtained.

[Average particle size]
The average particle diameters of the fiber-containing resin compositions of Examples 1 to 4 and Comparative Examples 2 to 3 were determined by a screening test method of JIS Z8815. The average particle size was defined as the particle size (median size in cumulative distribution) at an integrated value of 50% in the particle size distribution.

<Preparation of test piece>
Each of the fiber-containing resin compositions of Examples 1 to 5 and Comparative Examples 1 to 3 was preheated and then weighed, put into a mold, pressed to perform compression molding, 100 mm long × 100 mm wide × thickness A 4 mm structure was obtained. The compression molding conditions for obtaining the structure were set to a mold temperature of 165 to 180 ° C., a molding pressure of 15 to 40 MPa, and a compression time of 5 minutes.
Next, the obtained structure was post-cured at 200 ° C. for 4 hours to prepare a fiber-reinforced resin cured product (resin cured product).
Thereafter, a portion having a size of length 80 mm × width 10 mm × thickness 4 mm was cut out from the central portion of the cured resin product, and test pieces for evaluation shown below were produced.

<Evaluation of cured resin>
The following evaluation was performed about the test piece for evaluation produced using the fiber containing resin composition of Examples 1-5 and Comparative Examples 1-3, respectively. The evaluation results are shown in Table 2 below.

[Measurement of bending strength]
The test specimen for evaluation was heat-treated at 280 ° C. for 250 hours.
The bending strength (MPa) of each test piece before heat treatment (immediately after production) and after heat treatment at 280 ° C. for 250 hours was measured in accordance with ISO 178.

[Measurement of flexural modulus]
The test specimen for evaluation was heat-treated at 280 ° C. for 250 hours.
The flexural modulus (GPa) of each test piece before heat treatment (immediately after production) and after heat treatment at 280 ° C. for 250 hours was measured according to ISO 178.

[Measurement of fractal value]
A part having a size of 5 mm length × 10 mm width × 4 mm thickness was cut out from the central part of the test piece for evaluation to obtain a test piece for measuring a fractal value (fractal dimension (D) value). The fractal value of this test piece was calculated by the following procedures (11) to (14).
Procedure (11) First, a two-dimensional image obtained from data measured using X-ray CT was binarized.
Procedure (12) Next, the entire two-dimensional image was divided so that each of the X direction and the Y direction was equally divided into n (n = 6, 12, 16, 25, 36, 41, 82). This divided the entire image into n ² boxes.
Procedure (13) Next, the fiber area ratio in each box is calculated at each n value, and the coefficient of variation (C _v (n) = is calculated from the average value (a) and the standard deviation (σ) of the fiber area ratio. σ / a) was calculated.
Procedure (14) Next, each n value is plotted in a log-log graph in which the x axis is the reciprocal of the n value “1 / n” and the y axis is the coefficient of variation “C _v (n)”, and the obtained approximation A value obtained by multiplying the slope of the straight line by “−1” was defined as a fractal dimension (D) value.

[Measurement of standard deviation of orientation tensor value]
A portion having a size of 5 mm length × 10 mm width × 4 mm thickness was cut out from the central portion of the test piece for evaluation, and used as a test piece for measuring the standard deviation of the orientation tensor value. The standard deviation of the orientation tensor value of this test piece was calculated by the following procedures (21) to (24).
Procedure (21) First, a three-dimensional model was reconstructed from data measured using X-ray CT.
Procedure (22) For the three-dimensional model, the fiber and the resin were binarized and separated.
Procedure (23) The fiber direction tensor (Txx, Tyy, Tzz) was calculated. Txx, Tyy, and Tzz indicate alignment tensors in the X-axis, Y-axis, and Z-axis directions, respectively. Further, Txx + Tyy + Tzz = 1. When each orientation tensor value is 0.33, it can be evaluated that the orientation is random.
Procedure (24) The standard deviation was calculated from Txx, Tyy, Tzz whose total number of data in the analysis range was about 2000.

As shown in Table 2, the resin cured product in which the fiber-containing resin composition of Example 5 (pellets obtained in Preparation Example 5) was used was obtained in the fiber-containing resin composition of Comparative Example 1 (Preparation Example 1). It can be confirmed that the value (characteristic value) of the bending strength before the heat treatment is larger and the mechanical strength is higher than that of the resin cured product using the obtained pellets.
Furthermore, the resin cured product in which the fiber-containing resin composition of Example 5 was used was the fiber-containing resin composition of Comparative Example 2 (resin structure containing fibers dispersed in a state of being opened in a thermosetting resin). Even if compared with the resin cured product in which) is used, it can be confirmed that the value (characteristic value) of the bending strength before the heat treatment is large and the mechanical strength is further increased.
Even after the heat treatment at 280 ° C. for 250 hours, the cured resin using the fiber-containing resin composition of Example 5 is compared with the cured resin using the fiber-containing resin composition of Comparative Examples 1 and 2. Thus, it can be confirmed that the values (characteristic values) of the bending strength and the flexural modulus are large and the heat resistance is excellent.

Moreover, as shown in Table 2, the resin cured product in which the fiber-containing resin compositions of Examples 1 to 4 (resin structures containing fibers dispersed in a state of being opened in the thermosetting resin) were used. Bending strength before heat treatment compared to a resin cured product in which the fiber-containing resin composition of Comparative Example 2 (resin structure containing fibers dispersed in a state of being opened in a thermosetting resin) is used. It can also be confirmed that the value (characteristic value) of the flexural modulus is large and the mechanical strength is further increased.
Even after the heat treatment at 280 ° C. for 250 hours, the cured resin using the fiber-containing resin composition of Examples 1 to 4 is compared with the cured resin using the fiber-containing resin composition of Comparative Example 2. The values (characteristic values) of bending strength and bending elastic modulus are large. In addition, in the resin cured products in which the fiber-containing resin compositions of Examples 1 to 4 are used, the ratio of each characteristic value after the heat treatment / before the heat treatment (an index of deterioration suppression) is maintained high, in other words. In this case, the rate of deterioration (characteristic value decrease) is kept low, and it can be confirmed that the heat resistance is excellent.

  In particular, in the resin cured product in which the fiber-containing resin compositions of Examples 2 and 3 containing melamine polyphosphate as an antioxidant are used, the bending strength and bending elastic modulus values (characteristic values) before and after heat treatment are high. All were large, and the ratio of each characteristic value after heat treatment / before heat treatment (an index of deterioration suppression) was maintained high. Therefore, it can be confirmed that the cured resin obtained by curing the fiber-containing resin compositions of Examples 2 and 3 has higher mechanical strength and excellent heat resistance.

  Moreover, as a result of calculating the fractal value of each test piece, the fractal dimension (D) value of the resin cured product in which the fiber-containing resin compositions of Examples 1 to 4 were used was 0.40 to 0.60. there were. The fractal dimension (D) value of the resin cured product in which the fiber-containing resin compositions of Comparative Examples 2 to 3 were used was 0.20 to 0.30. Therefore, it was suggested that the cured and cured products using the fiber-containing resin compositions of Examples 1 to 4 have good fiber opening and dispersion states in the thermosetting resin.

  Moreover, as a result of calculating the standard deviation of the orientation tensor value of each test piece, all of the standard deviations of the orientation tensor values of the cured resin products using the fiber-containing resin compositions of Examples 1 to 4 were 0.12 to 0.12. It was 0.15. The standard deviations of the orientation tensor values of the cured resin products in which the fiber-containing resin compositions of Comparative Examples 2 to 3 were used were 0.23 to 0.26, respectively. Therefore, it was suggested that in the resin cured products in which the fiber-containing resin compositions of Examples 1 to 4 were used, the orientation of the fibers in the thermosetting resin tends to be closer to random orientation.

[Evaluation of cracking state]
The test piece for evaluation described above was heat-treated at 280 ° C. for 250 hours.
After the heat treatment, the test piece was cut into approximately halves, and the cut surface was observed with a microscope (magnification 30 times).

  Fig.6 (a) is an image which shows the cut surface of the test piece (after 250-hour heat processing under 280 degreeC) using the fiber containing resin composition of Example 1. FIG. FIG. 6B is an image showing a cut surface of a test piece (after heat treatment at 280 ° C. for 250 hours) in which the fiber-containing resin composition of Comparative Example 2 was used. FIG.6 (c) is an image which shows the cut surface of the test piece (after 250-hour heat processing under 280 degreeC) in which the fiber containing resin composition (pellet) of Example 5 was used. FIG. 6D is an image showing a cut surface of a test piece (after heat treatment at 280 ° C. for 250 hours) in which the fiber-containing resin composition (pellet) of Comparative Example 1 was used.

6 (a), only a small crack of about 1 mm at the maximum was observed on the test piece using the fiber-containing resin composition of Example 1 (after heat treatment at 280 ° C. for 250 hours). there were. In other Examples 2 to 4, only a small crack of about 1 mm at maximum was observed.
About FIG.6 (b), the big crack about 5-10 mm was seen by the test piece (after 250-hour heat processing under 280 degreeC) in which the fiber containing resin composition of the comparative example 2 was used. In Comparative Example 3, a large crack of about 5 to 10 mm was also observed.

About FIG.6 (c), the small crack about 5 mm at the maximum is seen by the test piece (after 250-hour heat processing under 280 degreeC) using the fiber containing resin composition (pellet) of Example 5. FIG. It was just.
6 (d), many large cracks exceeding 10 mm were observed in the test piece (after heat treatment at 280 ° C. for 250 hours) in which the fiber-containing resin composition (pellet) of Comparative Example 1 was used. .

  That is, the cured resin obtained by curing the fiber-containing resin compositions of Examples 1 to 4 and Example 5 is a cured resin obtained by curing the fiber-containing resin compositions of Comparative Examples 2 to 3 and Comparative Example 1. It can be confirmed that the mechanical strength is further improved and the heat resistance is excellent.

  The fiber-containing resin composition of the present invention has a thermosetting resin containing a resol-type phenol resin and fibers having an average length of 1 to 50 mm, and the content of the resol-type phenol resin in the thermosetting resin is It is 50 mass% or more. By using such a fiber-containing resin composition, a fiber-reinforced resin cured product having a uniform cross-linking structure and excellent in heat resistance and mechanical properties can be obtained without the need for a curing agent. The cured product can be suitably applied to a brake pad (back plate) or the like that requires heat resistance and mechanical strength. Therefore, the present invention has industrial applicability.

Claims (8)

A fiber-containing resin composition in which fibers are hardened with a thermosetting resin,
The thermosetting resin includes a resol type phenol resin,
The fibers have an average length in the range of 1-50 mm,
Content of the said resol type phenol resin in the said thermosetting resin is 50 mass% or more, The fiber containing resin composition characterized by the above-mentioned. The fibers are dispersed in an opened state in the thermosetting resin,
The average length of the fibers is in the range of 1-20 mm,
The fiber-containing resin composition according to claim 1, wherein an average density of the fiber-containing resin composition is in a range of 0.20 to 1.00 (g / cm ³ ). The fibers are dispersed in an opened state in the thermosetting resin,
The average length of the fibers is in the range of 1-20 mm,
The average bulk density of the resin composition is in the range of 0.15~0.60 (g / cm ^3), fiber-containing resin composition according to claim 1 or 2.   The fiber-containing resin composition according to any one of claims 1 to 3, wherein the thermosetting resin further contains a novolac type phenol resin.   A which is a ratio between the content A (mass%) of the resol type phenol resin contained in the thermosetting resin and the content B (mass%) of the novolac type phenol resin contained in the thermosetting resin. The fiber-containing resin composition according to claim 4, wherein the value of / B is in the range of 1 to 5.   The fiber-containing resin according to any one of claims 1 to 5, further comprising at least one selected from the group consisting of a phosphorus-based antioxidant, a hindered phenol-based antioxidant, and an amine-based antioxidant. Composition.   The fiber-containing resin composition according to any one of claims 1 to 6, further comprising an inorganic filler other than the fibers.   The fiber-containing resin composition according to any one of claims 1 to 7, which is used for a structural member.

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