Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/42—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof
  • C08G59/4215—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof cycloaliphatic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/20—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the epoxy compounds used
  • C08G59/22—Di-epoxy compounds
  • C08G59/28—Di-epoxy compounds containing acyclic nitrogen atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/4007—Curing agents not provided for by the groups C08G59/42 - C08G59/66
  • C08G59/4014—Nitrogen containing compounds
  • C08G59/4021—Ureas; Thioureas; Guanidines; Dicyandiamides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/42—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/50—Amines
  • C08G59/5046—Amines heterocyclic
  • C08G59/5053—Amines heterocyclic containing only nitrogen as a heteroatom
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/50—Amines
  • C08G59/5046—Amines heterocyclic
  • C08G59/5053—Amines heterocyclic containing only nitrogen as a heteroatom
  • C08G59/5073—Amines heterocyclic containing only nitrogen as a heteroatom having two nitrogen atoms in the ring
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
  • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
  • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
  • C08G59/50—Amines
  • C08G59/56—Amines together with other curing agents
  • C08G59/58—Amines together with other curing agents with polycarboxylic acids or with anhydrides, halides, or low-molecular-weight esters thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
  • C08J5/241—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres
  • C08J5/243—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres using carbon fibres
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
  • C08J5/249—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs characterised by the additives used in the prepolymer mixture
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
  • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
  • C08K5/1535—Five-membered rings
  • C08K5/1539—Cyclic anhydrides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
  • C08K7/04—Fibres or whiskers inorganic
  • C08K7/06—Elements
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2363/00—Characterised by the use of epoxy resins; Derivatives of epoxy resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/315—Compounds containing carbon-to-nitrogen triple bonds
  • C08K5/3155—Dicyandiamide

Definitions

• the present invention relates to a sheet molding compound and a fiber-reinforced composite material.
• a carbon fiber-reinforced composite material formed of carbon fiber and a matrix resin is widely used for airplanes, automobiles, and industrial uses.
• a matrix resin as the carbon fiber-reinforced composite material needs to express high mechanical characteristics even in a high-temperature environment.
• a matrix resin as a molding material sheet molding compound (hereinafter, described as SMC as well), prepreg, or the like) used for manufacturing the carbon fiber-reinforced composite material needs to have excellent molding properties.
• thermosetting resin a phenol resin, a melamine resin, a bismaleimide resin, an unsaturated polyester resin, an epoxy resin, and the like are used.
• the epoxy resin composition is suitable as a matrix resin because this resin has excellent molding properties, expresses excellent heat resistance after curing, and enables a carbon fiber-reinforced composite material prepared using the epoxy resin composition to exhibit high mechanical characteristics.
• the method for manufacturing a carbon fiber-reinforced composite material by molding a molding material includes an autoclave molding method, a filament winding molding method, a resin injection molding method, a vacuum resin injection molding method, a press molding method, and the like.
• the press molding method is in an increasing demand because this method has high productivity and makes it easy to obtain a carbon fiber-reinforced composite material excellent in terms of design.
• SMC constituted with reinforcing short fiber and a matrix resin is being actively used, because this material makes it possible to manufacture a carbon fiber-reinforced composite material having a complicated shape and produces a carbon fiber-reinforced composite material optimal for a structural member.
• the epoxy resin composition forms a cured material having excellent mechanical characteristics and heat resistance, it is difficult for the epoxy resin composition to satisfy both the quick curing properties and B stage stability.
• thermosetting resin composition obtained by diluting an unsaturated polyester resin or a vinyl ester resin with styrene is used.
• thermosetting resin composition containing the unsaturated polyester resin or the vinyl ester resin causes serious cure shrinkage, there is a demand for the development of SMC using an epoxy resin composition that causes less cure shrinkage.
• epoxy resin composition used in SMC As the epoxy resin composition used in SMC, the following compositions are suggested.
• Resin composition formed of a hydroxyl group-containing epoxy resin, polyol, and a polyisocyanate compound (PTL 1).
• Resin composition formed of an epoxy resin, polyol, a polyisocyanate compound, dicyandiamide, and a specific imidazole compound (PTL 2).
• Liquid adhesive formed of an epoxy resin, a curing agent activated at a temperature of 20° C. to 100° C., and a curing agent activated at a temperature of 100° C. to 200° C. (PTL 3).
• Reactive hot melt adhesive containing an epoxy resin staying in a solid state at room temperature, an epoxy resin staying in a liquid state at room temperature, amino group-terminated linear polyoxypropylene, and a latent curing agent (dicyandiamide) (PTL 4).
• epoxy resin compositions used in prepreg As epoxy resin compositions used in prepreg, the following compositions are suggested.
• Resin composition for impregnation containing an epoxy resin, a latent curing agent, a resin having a polymerizable unsaturated group, and a polymerization initiator (PTL 5).
• Epoxy resin composition containing an epoxy resin, an acid anhydride, and a Lewis acid salt (boron trichloride amine complex) (PTL 6 to 8).
• Resin composition containing an epoxy resin and 2,5-dimethyl-2,5-hexamethylenediamine and mencenediamine as curing agents (NPL 1).
• the resin compositions described in (1) and (2) exploit a urethanation reaction. Accordingly, due to the influence of moisture in the resin compositions, a thickening reaction rate and the condition of the B stage significantly change. Therefore, it is difficult to secure the handleability and workability of SMC and the B stage stability.
• the liquid adhesive described in (3) uses a curing agent (polyamine, mercaptan, isocyanate, imidazole, polyamide, polysulfide phenol, a BF 3 complex, ketimine, or the like) activated at a temperature of 20° C. to 100° C. Accordingly, this adhesive is gelated by a curing reaction as a first stage. Therefore, this adhesive exhibits low fluidity before curing as a second stage and is not easily bulked up, and consequently, cannot be used as a matrix resin of SMC.
• a curing agent polyamine, mercaptan, isocyanate, imidazole, polyamide, polysulfide phenol, a BF 3 complex, ketimine, or the like
• the reactive hot melt adhesive described in (4) has high viscosity, and reinforcing fiber cannot be excellently impregnated with the adhesive. Consequently, the adhesive cannot be used as a matrix resin of SMC.
• PTL 5 describes that in a case where prepreg is manufactured using the resin composition for impregnation described in (5), a solvent is incorporated into the resin composition for impregnation, and heating is performed such that the solvent is removed and a curing reaction partially proceeds. With this method, a solvent is easily removed. Therefore, this method is applicable to the manufacturing of thin prepreg in which a temperature variation resulting from thickness at the time of heating and cooling is small. However, in a thick sheet such as SMC, it is difficult to remove a solvent, and a large temperature variation occurs. Therefore, a defective product is obtained in which the surface condition becomes different from the interior condition after the B stage.
• the epoxy resin composition described in (6) consumes a long time until it shifts to the B stage at room temperature (23° C.). Furthermore, after the shift to the B stage at room temperature, the composition has low viscosity and extremely strong tackiness. Therefore, this composition is unsuitable for SMC.
• the resin composition described in (7) contains 2,5-dimethyl-2,5-hexanediamine. Therefore, the pot life of the composition is short. In addition, because this resin composition contains mecenediamine, the curing properties thereof are insufficient. Accordingly, this composition is unsuitable for a matrix resin of SMC.
• the present invention provides a sheet molding compound which is excellent in handleability (tackiness and draping properties) and fluidity and quick curing properties of a matrix resin at the time of pressing molding, can inhibit the occurrence of burrs, and makes it possible to obtain a fiber-reinforced composite material excellent in mold release properties, mechanical characteristics, and heat resistance; and a fiber-reinforced composite material excellent in mold release properties, mechanical characteristics, and heat resistance.
• the inventors of the present invention have found that the above object can be achieved by using a specific epoxy resin, an acid anhydride, and an epoxy resin curing agent, and have accomplished the present invention.
• the present invention has the following aspects.
• a sheet molding compound which is a thickened material of an epoxy resin composition, containing: a component (A), a component (B), and a component (C), in which the component (A) is an epoxy resin staying in a liquid state at 25° C., the component (B) is an acid anhydride, the component (C) is an epoxy resin curing agent, and in the thickened material, at least some of epoxy groups of the component (A) and at least some of carboxy groups derived from the component (B) form ester.
• Viscometry immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 30 minutes at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured.
• a fiber-reinforced composite material which is a cured material of the sheet molding compound described in any one of [1] to [19].
• the sheet molding compound of the present invention is excellent in reinforcing fiber impregnation properties, B stage stability, handleability (tackiness and draping properties) after the shift to the B stage, storage stability, quick curing properties at the time of heating, and fluidity and quick curing properties of a matrix resin at the time of press molding, and less causes a burr in a die.
• fiber-reinforced composite material of the present invention that is a cured material of the sheet molding compound is excellent in mold release properties, stiffness, mechanical characteristics, and heat resistance.
• “Staying in a liquid state at 25° C.” means that a substance stays in a liquid state under the condition of 25° C. and 1 atm.
• “Staying in a solid state at 25° C.” means that a substance stays in a solid state under the condition of 25° C. and 1 atm.
• Epoxy resin is a compound having two or more epoxy groups in a molecule.
• Acid anhydride group is a group having a structure formed in a case where one water molecule is removed from two acid groups (carboxy groups and the like).
• Acid anhydride is a compound having an acid anhydride group.
• “Hydrogenated phthalic anhydride” is a compound formed in a case where some or all of unsaturated carbon bonds in a benzene ring of phthalic anhydride are substituted with a saturated carbon bond.
• Viscosity is a value measured using a rheometer under the condition of measurement mode: constant stress, stress level: 300 Pa, frequency: 1.59 Hz, plate diameter: 25 mm, plate type: parallel plate, and plate gap: 0.5 mm.
• “Burr” is an unnecessary portion which is formed at the end of a molded article by a resin flowing and solidified in voids of a die at the time of press molding.
• “To” used for describing a range of numerical values means that the range includes numerical values listed before and after “to” as a lower limit and an upper limit.
• the sheet molding compound of the present invention is a thickened material of an epoxy resin composition which will be described later.
• the epoxy resin composition used in the present invention contains a component (A): epoxy resin staying in a liquid state at 25° C., a component (B): acid anhydride, and a component (C): epoxy resin curing agent.
• the sheet molding compound of the present invention is the thickened material.
• the epoxy resin composition may further contain a component (D): dicyandiamide.
• the component (C) may further contain a component (E): imidazole-based compound staying in a liquid state at 25° C.
• the epoxy resin composition used in the present invention may contain other components.
• the viscosity of the epoxy resin composition that is measured by the following viscometry (a) at 30° C. 30 minutes after the preparation of the composition is preferably 0.5 to 15 Pa ⁇ s, more preferably 0.5 to 10 Pa ⁇ s, and even more preferably 1 to 5 Pa ⁇ s.
• the viscosity measured at 30° C. 30 minutes after the preparation of the composition is equal to or higher than 0.5 Pa ⁇ s and more preferably equal to or higher than 1 Pa ⁇ s
• the accuracy of a basis weight (thickness of the epoxy resin composition) at the time of coating a film with the epoxy resin composition tends to be easily stabilized.
• the reinforcing fiber tends to be impregnated better with the epoxy resin composition.
• Viscometry immediately after being prepared, the epoxy resin composition is put and sealed into an airtightable container and left to stand for 30 minutes at 23° C., and then a viscosity of the epoxy resin composition at 30° C. is measured.
• the viscosity of the epoxy resin composition measured by the following viscometry (b) at 30° C. 10 days after the preparation of the composition is preferably 2,000 to 55,000 Pa ⁇ s, more preferably 2,000 to 42,000 Pa ⁇ s, and even more preferably 4,000 to 20,000 Pa ⁇ s.
• the viscosity measured at 30° C. 10 days after the preparation of the composition is equal to or higher than 2,000 Pa ⁇ s, and more preferably equal to or higher than 4,000 Pa ⁇ s, at the time of handling the sheet molding compound, the surface tackiness tends to be reduced.
• the viscosity of the epoxy resin composition measured by the following viscometry (c) at 30° C. 20 days after the preparation of the composition is preferably 2,000 to 100,000 Pa ⁇ s, more preferably 4,000 to 80,000 Pa ⁇ s, and even more preferably 5,000 to 70,000 Pa ⁇ s.
• the viscosity measured at 30° C. 20 days after the preparation of the composition is equal to or higher than 2,000 Pa ⁇ s, more preferably equal to or higher than 4,000 Pa ⁇ s, and even more preferably equal to or higher than 5,000 Pa ⁇ s, at the time of handling the sheet molding compound, the surface tackiness tends to be reduced.
• a viscosity (b) measured by the viscometry (b) and a viscosity (c) measured by the viscometry (c) satisfy a relationship of [viscosity (c)]/[viscosity (b)] ⁇ 3, because then the B stage stability tends to be further improved, the viscosity of the sheet molding compound tends to change less over time, and the storage stability tends to become excellent.
• [Viscosity (c)]/[viscosity (b)] is more preferably within a range of 0.3 to 3, and even more preferably within a range of 0.5 to 3.
• the component (A) is an epoxy resin staying in a liquid state at 25° C.
• the component (A) is a component which adjusts the viscosity of the epoxy resin composition to be within the above range such that reinforcing fiber is impregnated better with the epoxy resin composition at the time of manufacturing the sheet molding compound. Furthermore, the component (A) is a component which improves the mechanical characteristics and heat resistance of a fiber-reinforced composite material which is a cured material of the sheet molding compound. In a case where the component (A) has an aromatic ring, it is easy to adjust the mechanical characteristics of the fiber-reinforced composite material to be within a desired range.
• component (A) examples include glycidyl ether of bisphenols (bisphenol A, bisphenol F, bisphenol AD, halogen-substituted bisphenols A, F, and AD, and the like); glycidyl ether of polyphenols obtained by a condensation reaction between phenols and an aromatic carbonyl compound; glycidyl ether of polyols (polyoxyalkylene bisphenol A and the like); a polyglycidyl compound derived from aromatic amines; and the like.
• bisphenols bisphenol A, bisphenol F, bisphenol AD, halogen-substituted bisphenols A, F, and AD, and the like
• glycidyl ether of polyphenols obtained by a condensation reaction between phenols and an aromatic carbonyl compound
• polyols polyols
• a polyglycidyl compound derived from aromatic amines and the like.
• a bisphenol-type epoxy resin is preferable, because this resin makes it easy to adjust the viscosity of the epoxy resin composition to be appropriate for impregnating reinforcing fiber with the composition, and makes it easy to adjust the mechanical characteristics of the fiber-reinforced composite material to be within a desired range.
• the bisphenol-type epoxy resin a difunctional bisphenol-type epoxy resin is preferable.
• a bisphenol A-type epoxy resin is more preferable, because the heat resistance and the chemical resistance of the fiber-reinforced composite material become excellent.
• a bisphenol F-type epoxy resin is more preferable, because the viscosity of this resin is lower than that of the bisphenol A-type epoxy resin having the approximately same molecular weight, and the elastic modulus of the fiber-reinforced composite material becomes high.
• difunctioinal bisphenol-type epoxy resin means a bisphenol-type epoxy resin having two epoxy groups in a molecule.
• the component (A) may be an epoxy resin having three or more functional groups.
• a trifunctional epoxy resin and a tetrafunctional epoxy resin can further improve the heat resistance of the fiber-reinforced composite material without significantly change the viscosity of the epoxy resin composition.
• trifunctional epoxy resin means a resin having three epoxy groups in a molecule.
• Tetrafunctional epoxy resin means a resin having four epoxy groups in a molecule.
• Examples of commercial products of the difunctional bisphenol-type epoxy resin include the following ones.
• jER registered trademark 825, 827, 828, 828EL, 828XA, 806, 806H, 807, 4004P, 4005P, 4007P, and 4010P manufactured by Mitsubishi Chemical Corporation,
• EPICLON (registered trademark) 840, 840-S, 850, 850-S, EXA-850CRP, 850-LC, 830, 830-S, 835, EXA-830CRP, EXA-830LVP, and EXA-835LV manufactured by DIC Corporation,
• EPOTORT (registered trademark) YD-115, YD-115G, YD-115CA, YD-118T, YD-127, YD-128, YD-128G, YD-128S, YD-128CA, YDF-170, YDF-2001, YDF-2004, and YDF-2005RL manufactured by NIPPON STEEL & SUMIKIN CHEMICAL CO., LTD., and the like.
• Examples of commercial products of the component (A) having two or more functional groups include the following ones.
• N-730A N-740, N-770, N-775, N-740-80M, N-770-70M, N-865, N-865-80M, N-660, N-665, N-670, N-673, N-680, N-690, N-695, N-665-EXP, N-672-EXP, N-655-EXP-S, N-662-EXP-S, N-665-EXP-S, N-670-EXP-S, N-685-EXP-S, and HP-5000 manufactured by DIC Corporation,
• the component (A) contains a glycidyl amine-based epoxy resin such as TETRAD-X
• a glycidyl amine-based epoxy resin such as TETRAD-X
• the viscosity (b) or the viscosity (c) can be controlled, the shift to the B stage proceeds within a short period of time at the time of manufacturing the sheet molding compound, and accordingly, the productivity thereof can be increased.
• the content of the resin is preferably about 1% to 30% by mass with respect to 100% by mass of the component (A).
• the content of the glycidyl amine-based epoxy resin is more preferably 2% to 20% by mass, and even more preferably 3% to 15% by mass.
• the time taken for the sheet molding compound to shift to the B stage tends to be suitably reduced.
• the storage stability of the sheet molding compound tends to be improved.
• One kind of component (A) may be used singly, or two or more kinds of components (A) may be used in combination.
• the content of the component (A) in the epoxy resin composition used in the present invention may be set such that the viscosity of the epoxy resin composition measured at 30° C. 30 minutes after the preparation of the composition becomes 0.5 to 15 Pa ⁇ s.
• the content of the component (A) varies with the type of the component (A).
• the content of the component (A) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is preferably 20% to 100% by mass, and more preferably 50% to 95% by mass.
• the content of the component (A) is within the above range, it is easy to adjust the viscosity of the epoxy resin composition to be within the above range, and the reinforcing fiber impregnation properties are improved. Furthermore, the heat resistance of the fiber-reinforced composite material is improved.
• the component (B) is an acid anhydride.
• the component (B) is a component which can act on the component (A) at room temperature and thickens the epoxy resin composition immediately after the composition is prepared such that the sheet molding compound shifts to the B stage.
• the component (B) stays in a liquid state at 25° C.
• the components in the epoxy resin composition can be uniformly mixed together, and the epoxy resin composition can be uniformly thickened.
• Examples of the component (B) include a cyclic acid anhydride having a structure formed in a case where one or more water molecules are removed from two or more acids in a molecule.
• the cyclic acid anhydride includes a compound having one cyclic acid anhydride group or two or more cyclic acid anhydride groups in a molecule.
• Examples of the compound having one cyclic acid anhydride group include dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, methyl himic anhydride, hexahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride, 3-acetamidophthalic anhydride, 4-pentene-1,2-dicarboxylic anhydride, 6-bromo-1,2-dihydro-4H-3,1-benzoxazine-2,4-dione, 2,3-anthracene dicarboxylic anhydride, and the like.
• Examples of the compound having two cyclic acid anhydride groups include glyceryl bisanhydrotrimellitate monoacetate, ethylene glycol bisanhydrotrimellitate, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, diphenyl-3,3′,4,4′-tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-tetralin-1,2-dicarboxylic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl
• phthalic anhydride or hydrogenated phthalic anhydride which may have a substituent is preferable, and a compound represented by Formula (I) or a compound represented by Formula (2) is more preferable.
• component (B) it is preferable to use a compound having two cyclic acid anhydrides in a molecule, because then the occurrence of burrs at the time of press molding can be reduced.
• One kind of component (B) may be used singly, or two or more kinds of components (B) may be used in combination.
• the content of the component (B) is preferably set such that the amount of acid anhydride groups with respect to 1 equivalent of epoxy groups contained in the epoxy resin composition becomes 0.1 to 0.5 equivalents, more preferably set such that the amount of the acid anhydride groups becomes 0.1 to 0.4 equivalents, and even more preferably set such that the amount of the acid anhydride groups becomes 0.1 to 0.3 equivalents.
• the sheet molding compound appropriately shifts to the B stage.
• the sheet molding compound tends to excellently shift to the B stage, appropriate tackiness tends to be obtained, and the mold release properties of a carrier film from the sheet molding compound tends to become excellent.
• the sheet molding compound tends to appropriately shift to the B stage, excellent draping properties tend to be obtained, and the workability of cutting, lamination, and the like of the sheet molding compound tends to become excellent.
• the content of the component (B) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is preferably 3 to 30 parts by mass.
• the content of the component (B) is more preferably 5 to 25 parts by mass, and even more preferably 8 to 20 parts by mass. In a case where the content of the component (B) is within the above range, the sheet molding compound appropriately shifts to the B stage.
• the sheet molding compound tends to excellently shift to the B stage, appropriate tackiness tends to be obtained, and the release properties of a carrier film from the sheet molding compound tend to become excellent.
• the sheet molding compound tends to appropriately shift to the B stage, excellent draping properties tend to be obtained, and the workability of cutting, lamination, and the like of the sheet molding compound tends to become excellent.
• the content of the compound with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is preferably 1 to 20 parts by mass.
• the content of the compound is more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass.
• the content of the compound having two cyclic acid anhydrides in a molecule is equal to or greater than 1 parts by mass with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition, the occurrence of burrs at the time of press-molding the sheet molding compound tends to be reduced. Furthermore, in a case where the content of the compound having two cyclic acid anhydrides in a molecule with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is equal to or smaller than 20% by mass, more preferably equal to or smaller than 10 parts by mass, and even more preferably equal to or smaller than 5 parts by mass, the fluidity of the sheet molding compound in a molding die at the time of press molding tends to become excellent.
• the component (C) is an epoxy resin curing agent.
• the component (C) is a component which functions as a curing agent for the epoxy resin and acts as a catalyst so as to cause the component (A) and the component (B) to react with each other at room temperature at the time of shift to the B stage during which the component (A) and the component (B) react with each other.
• the component (C) stays in a solid state at 25° C.
• the reaction of the component (C) tends to be inhibited at the time of manufacturing the sheet molding compound or at the time of storing the manufactured sheet molding compound, and the productivity, storage stability, handleability, fluidity at the time of molding, and the like of the sheet molding compound tend to become excellent.
• component (C) examples include aliphatic amine, aromatic amine, modified amine, secondary amine, tertiary amine, an imidazole-based compound, mercaptans, and the like.
• an imidazole-based compound having a melting point of 120° C. to 300° C. is preferable.
• 2,4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine can be suitably used.
• component (E) an imidazole-based compound staying in a liquid state at 25° C.
• component (C) an imidazole-based compound staying in a liquid state at 25° C.
• component (E) examples include 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, and the like.
• the content of the component (E) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is preferably 0.01 to 0.2 parts by mass, more preferably 0.01 to 0.1 parts by mass, and even more preferably 0.03 to 0.07 parts by mass.
• the content is equal to or greater than 0.01 parts by mass, and preferably equal to or greater than 0.03 parts by mass
• the time taken for the sheet molding compound to shift to the B stage tends to be reduced.
• the stability of the shift to the B stage of the sheet molding compound tends to become excellent.
• One kind of component (C) may be used singly, or two or more kinds of components (C) may be used in combination.
• the content of the component (C) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is preferably 0.1 to 25 parts by mass, more preferably 2 to 10 parts by mass, and even more preferably 3 to 7 parts by mass.
• the content of the component (C) is equal to or greater than 0.1 parts by mass, more preferably equal to or greater than 2 parts by mass, and even more preferably equal to or greater than 3 parts by mass, the quick curing properties at the time of molding the sheet molding compound tends to become excellent.
• the stability of the B stage at the time of manufacturing the sheet molding compound tends to become excellent.
• the particle diameter of the component (C) at 25° C. affects the characteristics of the sheet molding compound. For example, in a case where the particle diameter of the component (C) is large, the surface area of the component (C) becomes small, and in order to cure the epoxy resin composition within a short period of time, sometimes the content of the component (C) needs to be increased. In a case where the particle diameter of the component (C) is large, the proportion of the epoxy resin composition that enters the interior of reinforcing fiber is reduced, and consequently, sometimes the time taken for curing is increased.
• the average particle diameter of the component (C) is preferably equal to or smaller than 25 ⁇ m, and more preferably equal to or smaller than 15 ⁇ m. More specifically, the average particle diameter of the component (C) is preferably larger than 0 ⁇ m and equal to or smaller than 25 ⁇ m, and more preferably 1 to 15 ⁇ m.
• the average particle diameter can be measured using a particle size distribution analyzer adopting an image analysis method, a laser diffraction scattering method, a Coulter method, a centrifugal precipitation method, or the like as measurement principle.
• the component (D) is dicyandiamide.
• the epoxy resin composition described above further contains dicyandiamide, it is possible to further improve the toughness and heat resistance of the cured material of the sheet molding compound obtained from the epoxy resin composition without impairing the shift to the B stage of the sheet molding compound and the stability thereof as well as the quick curing properties.
• the content of the component (D) with respect to 100 parts by mass of the entire epoxy resin contained in the epoxy resin composition is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 5 parts by mass, and even more preferably 1 to 4 parts by mass.
• the content of the component (D) is equal to or greater than 0.1 parts by mass, more preferably equal to or greater than 0.3 parts by mass, and even more preferably equal to or greater than 1 part by mass
• the toughness or heat resistance of the cured material of the sheet molding compound tends to become excellent.
• the content of the component (D) is equal to or smaller than 5 parts by mass and more preferably equal to or smaller than 4 parts by mass, the B stage stability at the time of manufacturing the sheet molding compound tends to become excellent.
• Examples of other components that the aforementioned epoxy resin composition may contain if necessary include a curing accelerator for an epoxy resin, an inorganic filler, an internal release agent, a surfactant, an organic pigment, an inorganic pigment, an epoxy resin composition other than the component (A), other resins (a thermoplastic resin, a thermoplastic elastomer, and an elastomer), and the like.
• a urea compound is preferable because this compound improves the mechanical characteristics (bending strength and flexural modulus) of the fiber-reinforced composite material.
• Examples of the urea compound include 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 2,4-bis(3,3-dimethylureide)toluene, 1,1′-(4-methyl-1,3-phenylene)bis(3,3-dimethylurea), and the like.
• inorganic filler examples include calcium carbonate, aluminum hydroxide, clay, barium sulfate, magnesium oxide, glass powder, hollow glass beads, aerosil, and the like.
• Examples of the internal release agent include carnauba wax, zinc stearate, calcium stearate, and the like.
• the release properties of a carrier film from the sheet molding compound can be improved. Furthermore, voids included in the sheet molding compound can be reduced.
• Examples of the epoxy resin other than the component (A) include an epoxy resin which stays in a semi-solid state or solid state at 25° C.
• an epoxy resin having an aromatic ring is preferable, and a difunctional epoxy resin is more preferable.
• various epoxy resins may be incorporated into the epoxy resin composition of the present invention.
• a polyfunctional epoxy resin, a novolac-type epoxy resin, or an epoxy resin having a naphthalene skeleton is effective.
• the thermoplastic resin, the thermoplastic elastomer, and the elastomer make the epoxy resin composition have appropriate viscosity, appropriate storage modulus, and appropriate thixotropic properties and improve the toughness of the cured material of the epoxy resin composition.
• One kind of each of the thermoplastic elastomer, the thermoplastic elastomer, and the elastomer may be used singly, or two or more kinds of these may be used in combination.
• the epoxy resin composition of the present invention can be prepared by the method known in the related art.
• the epoxy resin composition may be prepared by mixing together the components at the same time.
• a master batch may be prepared, and the epoxy resin composition may be prepared using the master batch.
• a method for inhibiting the increase of temperature such as controlling the kneading speed or cooling the preparation kiln or the kneading kiln.
• kneading devices examples include an electric mortar, attritor, a planetary mixer, a dissolver, a triple roll, a kneader, an all-purpose stirrer, a homogenizer, a homodispenser, a ball mill, a beads mill, and the like. Two or more kinds of kneading devices may be used in combination.
• the epoxy resin composition used in the present invention described above contains the component (A): epoxy resin staying in a liquid state at 25° C. as a main component, and accordingly, the viscosity of the just prepared composition can be reduced. For example, after 30 minutes, the viscosity of the epoxy resin composition at 30° C. can be equal to or lower than 15 Pa ⁇ s. Therefore, reinforcing fiber can be excellently impregnated with the epoxy resin composition, and the epoxy resin composition can be suitably used for manufacturing the sheet molding compound.
• the epoxy resin composition can be thickened within a short period of time after being prepared.
• the viscosity of the epoxy resin composition measured at 30° C. 10 days after the preparation of the composition can be 2,000 to 55,000 Pa ⁇ s. Therefore, the surface tackiness can be reduced at the time of handling the sheet molding compound, and appropriate draping properties can be obtained. Accordingly, excellent handleability can be obtained.
• the viscosity of the thickened epoxy resin composition can be maintained for a long period of time.
• the viscosity of the epoxy resin composition measured at 30° C. 20 days after the preparation of the composition can be 2,000 to 100,000 Pa ⁇ s. Therefore, the tackiness and draping properties after the shift to the B stage and the B stage stability become excellent.
• the epoxy resin composition contains the component (A), the stiffness, mechanical characteristics, and heat resistance of the cured material of the sheet molding compound are excellent.
• the sheet molding compound may contain reinforcing fiber.
• the reinforcing fiber various fibers can be adopted according to the use or usage purpose of the sheet molding compound. Examples thereof include carbon fiber (including graphite fiber, the same is true for the following description), aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, tungsten carbide fiber, glass fiber, and the like. In view of mechanical characteristics of the fiber-reinforced composite material, carbon fiber and glass fiber are preferable, and carbon fiber is particularly preferable.
• the reinforcing fiber is used in the form of a reinforcing fiber tow constituted with 1,000 to 60,000 filaments.
• the reinforcing fiber is present by maintaining the form of the reinforcing fiber tow, or present by being further divided into tows constituted with fewer filaments.
• the reinforcing fiber is present by being further divided into smaller tows.
• the length of the short fiber is preferably 0.3 to 10 cm, and more preferably 1 to 5 cm. In a case where the length of the short fiber is equal to or greater than 0.3 cm, a fiber-reinforced composite material having excellent mechanical characteristics is obtained. In a case where the length of the short fiber is equal to or smaller than 10 cm, SMC exhibiting excellent fluidity at the time of press molding is obtained.
• the reinforcing fiber in SMC is in the form of a sheet constituted with chopped reinforcing fiber tows that are two-dimensionally and randomly stacked.
• SMC is manufactured by sufficiently impregnating a sheet-like substance formed of the chopped reinforcing fiber tows with the epoxy resin composition and thickening the epoxy resin composition.
• reinforcing fiber is impregnated with the epoxy resin composition by a known method appropriate for the form of the reinforcing fiber and then held as it is for several days to tens of days at a temperature of about room temperature to 60° C. or for several seconds to tens of minutes at a temperature of about 60° C. to 80° C.
• an epoxy group which is contained in the component (A) in the epoxy resin composition and other epoxy resins optionally mixed in, and a carboxy group derived from the component (B) cause a esterification reaction, and accordingly, the epoxy resin composition shifts to the B stage.
• reaction condition for the epoxy group contained in the epoxy resin and the carboxy group derived from the component (B) such that the viscosity of the thickened material of the epoxy resin composition obtained after the esterification reaction that is measured at 30° C. falls into the range described above.
• Two sheets of films uniformly coated with the epoxy resin composition are prepared. Chopped reinforcing fiber tows are randomly scattered on the surface of one of the films coated with the epoxy resin composition, thereby obtaining a sheet-like substance.
• the surface of the other film coated with the epoxy resin composition is bonded to the surface of the sheet-like substance, and the sheet-like substance is pressed so as to be impregnated with the epoxy resin composition. Then, the epoxy resin composition is allowed to be thickened. In this way, SMC with suppressed surface tackiness that is suitable for a molding operation is obtained.
• SMC of the present invention described above contains the thickened material of the epoxy resin composition exhibiting excellent tackiness and draping properties after the shift to the B stage. Therefore, the SMC has excellent handleability (tackiness and draping properties).
• SMC of the present invention contains the thickened material of the epoxy resin composition of the present invention that is excellent in the B stage stability. Therefore, the SMC is excellent in the fluidity of the matrix resin at the time of press molding and can inhibit the occurrence of burrs in a die.
• SMC of the present invention exhibits excellent quick curing properties at the time of press molding. Due to the high curing speed at the time of press molding, the SMC stays in a die for a short period of time, and hence the productivity of the fiber-reinforced composite material is improved.
• SMC of the present invention contains the thickened material of the epoxy resin composition producing a cured material excellent in stiffness, mechanical characteristics, and heat resistance. Therefore, from the SMC, it is possible to obtain a fiber-reinforced composite material excellent in mold release properties, mechanical characteristics, and heat resistance.
• the fiber-reinforced composite material of the present invention is a cured material of SMC of the present invention.
• the fiber-reinforced composite material of the present invention is manufactured by heat-molding SMC and curing the epoxy resin composition having shifted to the B stage.
• Examples of the method for manufacturing the fiber-reinforced composite material by using SMC include the following method.
• One sheet of SMC or a substance constituted with a plurality of sheets of stacked SMC is set between a pair of dies.
• SMC is heated and compressed for 2 to 60 minutes at a temperature of 120° C. to 230° C. such that the epoxy resin composition is cured, thereby obtaining a fiber-reinforced composite material as a molded article.
• a honeycomb structure such as a corrugated board may be used, and SMC may be disposed on either or both of the surfaces thereof.
• the fiber-reinforced composite material of the present invention described above is a cured material of SMC of the present invention. Therefore, the material is excellent in mold release properties, mechanical characteristics, and heat resistance.
• jER (registered trademark) 828 bisphenol A-type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, viscosity at 25° C.: 12 Pa ⁇ s)
• jER registered trademark 807: bisphenol F-type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, viscosity at 25° C.: 4 Pa ⁇ s)
• jER registered trademark 604: tetraglycidyldiamine diphenylmethane (manufactured by Mitsubishi Chemical Corporation, viscosity at 25° C.: 360 Pa ⁇ s)
• jER registered trademark
• 630 triglycidyl-p-aminophenol (manufactured by Mitsubishi Chemical Corporation, viscosity at 25° C.: 0.7 Pa ⁇ s)
• TETRAD-X N,N,N′,N′-tetraglycidyl-m-xylylenediamine (manufactured by Mitsubishi Chemical Corporation, viscosity at 25° C.: 2 Pa ⁇ s)
• HN-2200 3-methyl-1,2,3,6-tetrahydrophthalic anhydride or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd., viscosity at 25° C.: 75 mPa ⁇ s)
• HN-2000 3-methyl-1,2,3,6-tetrahydrophthalic anhydride or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd., viscosity at 25° C.: 40 mPa ⁇ s)
• HN-5500 3-methyl-hexahydrophthalic anhydride or 4-methyl-hexahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd., viscosity at 25° C.: 75 mPa ⁇ s)
• MHAC-P methyl-5-norbornene-2,3-dicarboxylic anhydride (manufactured by Hitachi Chemical Co., Ltd., viscosity at 25° C.: 225 mPa ⁇ s)
• HN-2200 3-methyl-1,2,3,6-tetrahydrophthalic anhydride or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd.)
• MH-700 mixture of 4-methyl-hexahydrophthalic anhydride and hexahydrophthalic anhydride (manufactured by New Japan Chemical Co., Ltd.)
• TMEG-600 ethylene glycol bis(anhydrotrimellitate) (manufactured by New Japan Chemical Co., Ltd.)
• MTA-15 mixture of 4-methyl-hexahydrophthalic anhydride, hexahydrophthalic anhydride, and glycerylbis(anhydrotrimellitate)monoacetate (manufactured by New Japan Chemical Co., Ltd.)
• 2MZA-PW 2,4-diamino-6-[2′-methylimidazole-(1′)]-ethyl-s-triazine (manufactured by SHIKOKU CHEMICALS CORPORATION, inciting point: 253° C.)
• DICYANEX 1400F dicyandiamide (manufactured by Air Products and Chemicals, Inc.)
• DY9577 boron trichloride amine complex (manufactured by Huntsman Corporation, melting point: 28° C. to 35° C.)
• DICYANEX 1400F, 2MZA-PW, and TMEG-600 was mixed with jER (registered trademark) 828 at 1:1 (mass ratio). The mixtures were kneaded using a triple roll, thereby obtaining a master batch.
• the epoxy resin composition was put and sealed into an airtightable container, and stored by being left to stand in a room at 23° C. in a place protected from direct sunlight. Thirty minutes, 10 days, and 20 days after the preparation of the epoxy resin composition, the viscosity of the composition was measured as below.
• the plate of a rheometer (manufactured by TA Instruments, Inc., AR-G2) was preheated to 30° C. and kept as it was until the temperature became stable. After the temperature was found to be stable, the epoxy resin composition was isolated into a plate, the gap was adjusted, and then the measurement was started under the following condition. For 10 minutes, 10 spots were measured, and the average thereof was adopted as viscosity.
• the epoxy resin composition was put and sealed into an airtightable container, and stored by being left to stand in a room at 23° C. in a place protected from direct sunlight. Seven days after the preparation of the epoxy resin composition, the viscosity of the composition was measured as below.
• the plate of a rheometer (manufactured by Thermo Fisher Scientific, MARS40) was preheated to 30° C. and kept as it was until the temperature became stable. After the temperature was found to be stable, the epoxy resin composition was isolated into a plate, the gap was adjusted, and then the measurement was started under the following condition. For 10 minutes, 10 spots were measured, and the average thereof was adopted as viscosity.
• Temperature increased at 2° C./min from 30° C. to a temperature at which the curing reaction of the epoxy resin composition was about to start (that is, a temperature at which the viscosity was rapidly increased)
• the viscosity of the epoxy resin composition measured at 30° C. 30 minutes after the preparation of the composition is a measure of impregnation properties at the time of impregnating reinforcing fiber with the epoxy resin composition.
• the viscosity after 30 minutes was evaluated based on the following standards.
• the viscosity of the epoxy resin composition measured at 30° C. 10 days after the preparation of the composition is a measure for determining whether SMC demonstrates appropriate tackiness and draping properties within a short period of time and whether excellent handleability is maintained.
• the viscosity after 10 days was evaluated based on the following standards.
• the viscosity of the epoxy resin composition measured at 30° C. 20 days after the preparation of the composition is a measure for determining whether a thickened material in a B stage is obtained which enables SMC to demonstrate appropriate tackiness or draping properties. Furthermore, the viscosity of the epoxy resin composition measured at 30° C. 20 days after the preparation of the composition is a measure for determining whether the B stage is maintained for a long period of time (B stage stability). The viscosity after 20 days was evaluated based on the following standards.
• the viscometry under heating condition is a measure of fluidity of SMC at the time of press molding.
• the higher the viscosity at which the curing reaction of the epoxy resin composition is about to start that is, the higher the viscosity that will be rapidly increased
• the viscosity under a heating condition was evaluated based on the following standards.
• the viscosity after 7 days at which the curing reaction of the epoxy resin composition was about to start is 0.5 Pa ⁇ s to 500 Pa ⁇ s (fluidity of SMC at the time of press molding was excellent).
• the viscosity after 7 days at which the curing reaction of the epoxy resin composition was about to start was less than 0.5 Pa ⁇ s or higher than 500 Pa ⁇ s.
• the burrs can be removed within a short period of time after molding. Accordingly, the molding cycle can be shortened.
• a die having a size of 300 mm (length) ⁇ 300 mm (width) ⁇ 2 mm (thickness) was charged with a laminated substance obtained by laminating SMC having a size of 300 mm (length) ⁇ 300 mm (width) in 2 ply.
• the laminated substance was heated and compressed for 5 minutes, thereby obtaining a 300 mm ⁇ 300 mm flat plate-like fiber-reinforced composite material having a thickness of about 2 mm (CFRP molding plate).
• a burr occurrence rate at the time of manufacturing the CFRP molding plate was calculated by the following equation.
• X represents the weight of SMC with which the die was charged
• Y represents the weight of the molded article taken out of the die after molding.
• the epoxy resin composition was weighed and put into a standard Hermetic aluminum pan of a differential scanning calorimeter (manufactured by TA Instrument, Inc., Q1000), and a standard aluminum lid of the device was put on the pan, thereby creating a sample According to the temperature control program of the device, the sample was heated to 140° C. from 30° C. at 200° C./min and then kept under an isothermal condition at 140° C. for 30 minutes. In this way, a DSC heating curve of the epoxy resin composition at a series of control temperatures was obtained.
• a tangent was drawn from a point, at which the slope of a curve is maximum along which the heating amount was getting reduced from the peak of the heating amount, and a tangent (baseline) was drawn from a portion where the heating resulting from the curing reaction was stopped.
• the time on the intersection point between these tangents was adopted as a curing finish time.
• the curing finish time is a measure of a molding time of a molding material.
• the curing finish time was equal to or shorter than 10 minutes (quick curing properties were excellent).
• the epoxy resin composition was defoamed in a vacuum and injected into the space between two sheets of glass plates having a thickness of 4 mm between which a polytetrafluoroethylene spacer having a thickness of 2 mm was interposed. Under the condition by which the surface temperature of the glass plates became 140° C., the epoxy resin composition was heated for 10 minutes in a hot air circulation-type thermostatic furnace and then cooled, thereby obtaining a cured resin plate.
• Span length set by actually measuring the thickness of the cured resin plate and multiplying the thickness by 16 (unit mm)
• the cured resin plate was processed into a 55 mm (length) ⁇ 12.5 mm (width) test piece and measured at a measurement frequency of 1 Hz and a heating rate of 5° C./min by using a rheometer (TA Instrument, Inc., ARES-RDA).
• log G′ was plotted for temperature, and a temperature on an intersection point between an approximating line of a region where log G′ was constant and an approximating line of a region where log G's was rapidly reduced was recorded as a glass transition temperature (G′ ⁇ Tg (° C.)).
• the peak top of Log G′′ was denoted as G′′ ⁇ Tg (° C.).
• the peak top of tan ⁇ was denoted as tan ⁇ (° C.).
• the heat resistance was evaluated based on the following standards.
• the glass transition temperature (G′ ⁇ Tg) was equal to or higher than 130° C. (heat resistance was excellent).
• Example 1 2 3 4 5 6 Component jER ®828 100 100 100 100 100 100 100 100 (A) Component HN-2200 14 14 12.5 12.5 11 11 (B) Component 2MZA-PW 4 6 4 6 4 6 (C) Epoxy group equivalent 0.54 0.54 0.54 0.54 0.54 0.54 Acid anhydride group equivalent 0.17 0.17 0.15 0.15 0.13 0.13 Acid anhydride group/epoxy 0.31 0.31 0.28 0.28 0.25 0.25 group Viscosity at After 30 minutes 2.6 2.7 2.8 2.9 2.9 3.2 30° C.
• the epoxy resin compositions of Examples 1 to 23 have a low viscosity 30 minutes after the preparation of the compositions and exhibit excellent impregnation properties at the time of manufacturing SMC. Furthermore, 10 days after the preparation of these epoxy resin compositions, these compositions have appropriately shifted to the B stage. In a case where these compositions are made into SMC, the tackiness and draping properties thereof are appropriate. In addition, the B stage stability thereof is also excellent. These compositions also have excellent quick curing properties, and in a case where the compositions are made into SMC, they can be molded within a short period of time.
• the cured material of SMC obtained from the epoxy resin compositions of Examples 1 to 23 less causes burrs, and the bending strength, flexural modulus, and heat resistance thereof are also high.
• Comparative Examples 1 and 2 are examples in which epoxy resin compositions are prepared with reference to PTL 6 to 8.
• the epoxy resin compositions of Comparative Examples 1 and 2 have a low viscosity 30 minutes after the preparation of the compositions and exhibit excellent impregnation properties. However, these compositions have a low viscosity 20 days after the preparation of the compositions and have extremely strong tackiness. In a case where these compositions are used as a molding material, due to the strong tackiness, the handleability thereof is poor. Furthermore, because the quick curing properties thereof are poor, it takes a long time to cure the compositions. In a case where these compositions are used as a molding material, the time for which the material stays in a die is lengthened.
• Comparative Example 3 is an example in which an epoxy resin composition is prepared with reference to PTL 6 to 8.
• the epoxy resin compositions of Comparative Example 3 has a low viscosity 30 minutes after the preparation of the composition and exhibits excellent impregnation properties. Furthermore, 20 days after the preparation of the composition, the composition has appropriately shifted to the B stage. In a case where the composition is used as a molding material, the tackiness and draping properties thereof are appropriate. However, because the quick curing properties thereof are poor, it takes a long time to cure the composition. In a case where the composition is used as a molding material, the time for which the material stays in a die is lengthened.
• a carrier film made of polyethylene was coated with the epoxy resin composition formulated as shown in Table 6 at 600 g/m 2 .
• the epoxy resin composition formulated as shown in Table 6 at 600 g/m 2 .
• chopped carbon fiber tows which were obtained by cutting a carbon fiber tow constituted with 15,000 filaments (manufactured by Mitsubishi Rayon Co., Ltd., TR50S 15L) in a length of 25 mm, were scattered such that the basis weight of the carbon fiber substantially became uniform at 1,200 g/m 2 and the fiber direction of the carbon fiber became random.
• a carrier film made of polyethylene was coated with the same epoxy resin composition at 600 g/m 2 .
• the chopped carbon fiber tows were sandwiched between two sheets of the carrier films such that the side of the epoxy resin composition became inside.
• the carrier films were pressed by being passed between rolls such that the chopped carbon fiber tows were impregnated with the epoxy resin composition, thereby obtaining a SMC precursor.
• the SMC precursor was left to stand at room temperature (23° C.) for 20 days such that the epoxy resin composition in the SMC precursor was sufficiently thickened, thereby obtaining SMC.
• SMC was laminated in 2ply, a molding die was charged with the laminated SMC at a charge ratio of 65% (ratio of the area of SMC to the area of the die), and SMC was heated and compressed for 5 minutes under the condition of a die temperature of 140° C. and a pressure of 4 MPa such that the epoxy resin composition was cured, thereby obtaining a 200 mm ⁇ 300 mm flat plate-like fiber-reinforced composite material having a thickness of about 2 mm (CFRP molding plate). The following measurement and evaluation were performed. The results are shown in Table 6.
• the SMC precursor was cut in a length of about 30 cm, and the impregnation condition was visually checked and evaluated based on the following standards.
• the tackiness of SMC was evaluated based on the following standards.
• the draping properties of SMC were evaluated based on the following standards.
• SMC was appropriately flexible to the touch, and it was easy to cut and carry SMC.
• the handleability of SMC was evaluated based on the following standards.
• B either or both of the tackiness and draping properties were evaluated as B.
• the CFRP molding plate was processed into a 55 mm (length) ⁇ 12.5 mm (width) test piece and measured at a measurement frequency of 1 Hz and a heating rate of 5° C./min by using a rheometer (TA Instrument, Inc., ARES-RDA).
• log G′ was plotted for temperature, and a temperature on an intersection point between an approximating line of a region where log G′ was constant and an approximating line of a region where log G's was rapidly reduced was recorded as a glass transition temperature (G′ ⁇ Tg (° C.)).
• the peak top of Log G′′ was denoted as G′′ ⁇ Tg (° C.).
• the peak top of tan ⁇ was denoted as tan ⁇ (° C.).
• the heat resistance was evaluated based on the following standards.
• the glass transition temperature (G′ ⁇ Tg) was equal to or higher than 130° C. (heat resistance was excellent).
• epoxy resin compositions were obtained in the same manner as in Examples 1 to 23.
• the epoxy resin compositions were measured and evaluated in the same manner as in Examples 1 to 23. The results are shown in Table 7.
• the epoxy compositions of Examples 27 to 30 have a low viscosity 30 minutes after the preparation of the compositions, and at the time of manufacturing SMC, the compositions exhibit excellent impregnation properties. Furthermore, 10 days after the preparation of these epoxy resin compositions, these compositions have appropriately shifted to the B stage. In a case where these compositions are made into SMC, the tackiness and draping properties thereof are appropriate. In addition, the B stage stability thereof is also excellent. These compositions also have excellent quick curing properties, and in a case where the compositions are made into SMC, they can be molded within a short period of time.
• the cured material of SMC obtained from the epoxy resin compositions of Examples 27 to 30 less causes burrs, and the bending strength, flexural modulus, and heat resistance thereof are also high.
• the sheet molding compound of the present invention is excellent in the reinforcing fiber impregnation properties, the tackiness and draping properties after the shift to the B stage, the B stage stability (fluidity at the time of press molding), the quick curing properties at the time of heating (staying in a die for a short period of time at the time of press molding), and forms a cured material having excellent heat resistance. Furthermore, owing to its excellent mechanical characteristics and heat resistance after curing, the sheet molding compound of the present invention is suitable as a raw material of structural parts for industries and automobiles.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Materials Engineering (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Inorganic Chemistry (AREA)
• Epoxy Resins (AREA)
• Reinforced Plastic Materials (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Related Parent Applications (1)

Related Child Applications (1)

Publications (1)

Family

ID=63792630

Family Applications (2)

Family Applications After (1)

Country Status (6)

Cited By (2)

Families Citing this family (11)

Family Cites Families (26)

• 2018
  • 2018-04-10 ES ES18783748T patent/ES2972887T3/es active Active
  • 2018-04-10 JP JP2018523820A patent/JP6708256B2/ja active Active
  • 2018-04-10 CN CN201880024018.1A patent/CN110536914B/zh active Active
  • 2018-04-10 EP EP18783748.9A patent/EP3611210B1/fr active Active
  • 2018-04-10 WO PCT/JP2018/015027 patent/WO2018190329A1/fr unknown
  • 2018-04-10 CN CN202310202953.5A patent/CN116333267A/zh active Pending
• 2019
  • 2019-10-07 US US16/594,122 patent/US20200032047A1/en not_active Abandoned
• 2020
  • 2020-05-08 JP JP2020082614A patent/JP6856157B2/ja active Active
• 2021
  • 2021-03-05 JP JP2021035293A patent/JP7151806B2/ja active Active
• 2022
  • 2022-09-27 JP JP2022153947A patent/JP7552668B2/ja active Active
  • 2022-10-07 US US17/938,881 patent/US20230046977A1/en active Pending
• 2024
  • 2024-05-09 JP JP2024076712A patent/JP2024097920A/ja active Pending

Also Published As

Similar Documents

Legal Events