JP6163763B2 - Epoxy resin composition, prepreg and film using the same, and fiber reinforced composite material - Google Patents

Description

  The present invention relates to an epoxy resin composition having excellent weather resistance and capable of being cured for a short time, and a prepreg and a fiber-reinforced composite material using the epoxy resin composition as a matrix resin.

  Fiber reinforced composite materials are widely used from sports / leisure applications to industrial applications such as automobiles and aircrafts, taking advantage of their light weight, high strength and high rigidity. Particularly in recent years, carbon fiber reinforced composite materials that are lighter and have higher strength and rigidity have been increasingly used for industrial applications.

  The molding method of the carbon fiber composite material uses a prepreg in which resin is pre-impregnated with straightly aligned carbon fibers as an intermediate material in order to prevent strength reduction due to fiber bending at the time of molding. A method of curing with a press is common. Particularly in recent years, short-time curing using press molding or the like has been demanded in order to reduce manufacturing costs.

  The carbon fiber composite material is not only used as a structural member by taking advantage of its characteristics, but there are cases where a cloth is laminated on the surface and a cloth is used as a design. In that case, a transparent surface treatment such as clear coating is often used.

  In the carbon fiber reinforced composite material, an epoxy resin is generally used as the matrix resin from the viewpoint of strength. However, bisphenol-type epoxy resins often used as general-purpose resins have an aromatic ring skeleton, and are susceptible to yellowing and vitiligo upon exposure to sunlight, and thus have limited limits for use as design parts. Therefore, Patent Document 1 proposes a resin composition in which the weather resistance is improved by reducing the amount of the aromatic ring skeleton. However, since the proposed acid anhydride curing agent is affected by moisture and the physical properties of the cured product are reduced, the use of acid anhydride is not preferable for prepregs that require a certain storage period until use. . In addition, a resin composition having a reduced aromatic ring skeleton and improved weather resistance has poor reactivity with amine compounds such as dicyandiamide, which is a solid curing agent that can be stored for a long period of time, and it has been difficult to cure in a short time.

Pamphlet of International Publication WO2003 / 002661

  An object of the present invention is to provide a prepreg which has good weather resistance and can be cured in a short time, a film, and a fiber-reinforced composite material formed by molding the prepreg.

  The gist of the present invention is an epoxy resin composition comprising at least an epoxy resin (A), an epoxy resin (B), dicyandiamide (C), toluenebisdimethylurea (D) and a curing aid amine adduct (E). The epoxy resin (A) is a hydrogenated bisphenol A type epoxy resin, and the epoxy resin (B) is an epoxy resin containing 1 to 4 groups represented by the structural formula (I) in the molecule. It is in the thing.

(N represents a natural number.)
Toluenebisdimethylurea (D) and curing aid amine adduct contained in the epoxy resin composition with respect to 100 parts by mass in total of the epoxy resin (A) and the epoxy resin (B) contained in the epoxy resin composition (E) is preferably an epoxy resin composition having 17.0 to 10.5 parts by mass and 0.5 to 7.0 parts by mass, respectively.

  Further, another gist of the present invention is a resin film using the resin composition, a prepreg obtained by impregnating a fiber base material with the resin composition, a fiber reinforced composite material obtained by laminating this, and the resin composition. And a fiber reinforced composite material using a fiber base material. Furthermore, it is a fiber reinforced composite material obtained by laminating the prepreg only on the surface exposed to light, and a fiber reinforced composite material obtained by laminating the resin film on the surface exposed to light. The epoxy resin composition of the present invention preferably contains an ultraviolet absorber, an antioxidant, or a light stabilizer. In the fiber reinforced composite material of the present invention, it is preferable to apply a protective film to the surface exposed to light, and the protective film is preferably a coating or a resin film.

  According to the present invention, it is possible to obtain a prepreg having a matrix resin that is a short-time-curable epoxy resin composition that gives a cured product having good weather resistance, and a fiber-reinforced composite material having good weather resistance is obtained by press molding. be able to.

"Epoxy resin (A)"
The epoxy resin (A) used in the epoxy resin composition of the present invention needs to be a hydrogenated bisphenol A type epoxy resin. The epoxy resin composition of the present invention can have a viscosity capable of being prepreg by adding a hydrogenated bisphenol A type epoxy resin and an epoxy resin (B) containing a group represented by the structural formula (I). . As the hydrogenated bisphenol A type epoxy resin, a resin having an appropriate molecular weight can be selected. Hydrogenated bisphenol A type epoxy resins are commercially available, for example, from Nippon Steel & Sumikin Chemical Co., Ltd., as ST-3000 and ST-4000D (product names) and from Mitsubishi Chemical Corporation as YX-8000 (product name).

"Epoxy resin (B)"
The epoxy resin (B) used in the epoxy resin composition of the present invention needs to be an epoxy resin containing 1 to 4 groups represented by the structural formula (I). By adding an epoxy resin containing a group represented by the structural formula (I) to the resin composition, white spots generated by a weather resistance test are not generated, and a cured product of the resin composition having a good appearance can be obtained. The epoxy resin containing the skeleton represented by the structural formula (I) can be industrially obtained. For example, it can be obtained from Daicel Corporation as EHPE3150 (product name). EHPE3150 (product name) is an epoxy resin having a structure in which a group represented by the structural formula (I) is bonded in place of three hydrogen bonded to carbon at one end of propane.

  The compounding composition of the epoxy resin (A) and the epoxy resin (B) used in the epoxy resin composition of the present invention has a mass ratio of 90:10 to 20:80 that can be prepregated, and exhibits heat resistance and weather resistance. Since it is excellent in property, it is preferable. More preferably, it is 40: 60-20: 80. More preferably, it is 30: 70-25: 75.

"Dicyandiamide (C)"
The curing agent used in the epoxy resin composition of the present invention needs to be dicyandiamide. By using dicyandiamide, a decrease in physical properties of the prepreg due to moisture can be suppressed, and a good fiber-reinforced composite material can be obtained. Dicyandiamide is commercially available. A preferred blending amount is a prepreg due to moisture such that the number of moles of active hydrogen of dicyandiamide is 0.6 to 1.0 times the number of moles of epoxy group calculated from the epoxy equivalent of epoxy resin (A). It is preferable from the viewpoint that a decrease in physical properties is suppressed and a good fiber-reinforced composite material is obtained. Furthermore, it is more preferable that it is 0.7 to 0.8 times because it is excellent in the expression of heat resistance and weather resistance.

"Toluenebisdimethylurea (D)"
The curing aid urea compound used in the epoxy resin composition of the present invention must be toluene bisdimethylurea. Toluenebisdimethylurea is industrially available and available from PTI Japan as Omicure 24 (product name).

"Curing aid Amine Adduct (E)"
In the epoxy resin composition of the present invention, it is necessary from the viewpoint of short-time curing that the curing aid amine adduct (E) is contained in the epoxy resin composition. The curing aid amine adduct (E) is available from Ajinomoto Fine Techno as Amicure PN-50 (product name). It is possible to cure for a short time by using toluene bisdimethylurea (D) and curing aid amine adduct (E) in combination with the epoxy resin composition. The preferable blending amount (mass) of the curing aid amine adduct (E) is 2 to 2.5 times the blending amount (mass) of dicyandiamide as the total amount (mass) of the curing assistant in terms of short-time curing. preferable. Most preferred is 2.3 times.

  With respect to 100 parts by mass of the total mass of the epoxy resin (A) and the epoxy resin (B) contained in the epoxy resin composition of the present invention, the toluene bisdimethylurea (D) and the curing aid amine adduct ( E) is preferably 17.0 to 10.5 parts by mass and 0.5 to 7.0 parts by mass, respectively, from the viewpoint of short-time curing. Each of 15.5 to 11.0 parts by mass and 2.0 to 6.5 parts by mass is more preferable because it can be cured in a shorter time.

"Other"
The epoxy resin composition of the present invention can use various antioxidants, ultraviolet absorbers, HALS (hindered amine light stabilizers) and the like that improve weather resistance.

  A thermoplastic resin may be blended in the epoxy resin composition of the present invention as necessary. Furthermore, an additive may be mix | blended with the epoxy resin composition of this invention as needed. Curing accelerator, silicone oil, natural wax, synthetic wax, metal salt of linear fatty acid, acid amide, ester, paraffin and other mold release agent, crystalline silica, fused silica, calcium silicate, alumina, carbonic acid Powders such as calcium, talc and barium sulfate, inorganic fillers such as glass fiber and carbon fiber, flame retardants such as chlorinated paraffin, bromotoluene, hexabromobenzene and antimony trioxide, colorants such as carbon black and bengara, A silane coupling agent or the like can be used.

"Fiber substrate (F)"
As the fiber base material (F) that can be used for the fiber-reinforced composite material and prepreg of the present invention, reinforcing fibers generally used as a fiber-reinforced composite material can be used. Carbon fiber, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, high-strength polyethylene fiber, tungsten carbide fiber, PBO fiber, glass fiber, etc. are mentioned, and these are used alone or in combination of two or more. It can be used as well. Carbon fiber is preferable. The fiber base material (F) is in the form of a tow as it is, in the form of a unidirectional material in which reinforcing fiber tows are aligned in one direction, in the form of a woven fabric, in the form of a nonwoven fabric made of reinforced fibers cut shortly, etc. Used in. In the case of a woven fabric, plain weave, twill weave, satin weave, etc. can be exemplified. Further, examples thereof include a sheet obtained by aligning fiber bundles represented by non-crimp fabrics in one direction, and a stitching sheet that is stitched so as not to loosen a sheet that is laminated by changing the angle of these fiber bundles. A unidirectional material is preferable because the resulting fiber-reinforced composite material has excellent mechanical properties. From the viewpoint of handleability, a woven fabric is preferable. The prepreg of the present invention is not limited in the fiber basis weight, but the greater the fiber basis weight, the better the performance.

  There is no special restriction | limiting in the manufacturing method of the prepreg of this invention. It can be manufactured by a general method. The epoxy resin composition of the present invention, which is a prepreg matrix resin, can be prepared with a glass flask, a kneader, a planetary mixer, a general stirring heating kettle, a stirring pressure heating kettle or the like. Examples of the method for applying the matrix resin to the fiber substrate include a hot melt film method and a lacquer method.

  There is no particular limitation on the method for molding the prepreg of the present invention, that is, the method for producing the fiber-reinforced composite material of the present invention. General molding methods such as autoclave molding, oven molding, press molding, continuous press molding, pultrusion molding, and internal pressure molding can be applied. In order to obtain a fiber-reinforced composite material in a short time, it is preferable to use a press molding method. A preferable curing temperature is 130 ° C to 150 ° C. More preferably, it is 140 degreeC.

  Furthermore, the present invention relates to a resin film using the epoxy resin composition of the present invention, a prepreg obtained by impregnating a fiber base material with the epoxy resin composition of the present invention, a fiber reinforced composite material formed by laminating the prepreg, and the resin. It is a fiber reinforced composite material using a composition and a fiber base material. It is a fiber-reinforced composite material obtained by laminating the prepreg only on the surface that is exposed to light. It is a fiber-reinforced composite material obtained by laminating the resin film on the surface that is exposed to light. It is preferable to contain an ultraviolet absorber, an antioxidant, and a light stabilizer. It is preferable to provide a protective film on the surface exposed to light. The protective film is preferably a paint or a resin film.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention does not receive a restriction | limiting by this.
The raw materials and fiber materials of the resin composition are shown in Table 1.

<Weather resistance test>
As a measuring device, a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd., product name: WEL-SUN-HC) was used. The temperature in the layer is set to 63 ± 3 ° C. and humidity is 50%, and pure water is allowed to fall for 12 minutes in 60 minutes of one cycle. The surface condition of the test piece after exposure is visually observed. In addition, Lab is measured using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name: SE2000), and a color difference ΔE before and after the weather resistance test is calculated.

<Torque value by curast meter>
Using a curast meter (manufactured by Nigo Shoji Co., Ltd., product name: IIF-HT), measurement mode P.I. P. (Peak measurement mode) Measured under conditions of vibration frequency 6 CPM, amplitude angle ± 3 °, measurement temperature 140 ° C., and torque value 10 minutes after the start of measurement is measured. The value obtained here is an indicator of the speed of curing of the epoxy resin composition.

<Examples 1-4, Comparative Examples 1-6>
(Procedure for preparing resin compositions A to J)
Each resin composition was adjusted according to the following procedure.
Master batch 1 was prepared by uniformly dispersing a part of ST-3000 as an epoxy resin (A), Dicy 15 as dicyandiamide (C), and Omicure 24 as toluene bisdimethylurea (D) with a three-roll mill. A master batch 2 was prepared by dispersing a part of ST-3000 as an epoxy resin (A) and Amicure PN-50 as a curing aid amine adduct (E) using a hybrid mixer. Master batch 3 was prepared by dissolving ST-3000 as the remaining epoxy resin (A) and EHPE3150 as the epoxy resin (B) at 140 ° C. Master batches 1 and 3 were dissolved at 75 ° C., and master batch 2 was further added and mixed at 65 ° C. to obtain a resin composition.

(Preparation of resin compositions A to J)
Resin compositions A to J were obtained according to the above procedure, with the blending amounts of resin compositions A to J shown in Table 2.
Using the resin compositions A to J, the torque value after 10 minutes at 140 ° C. was measured using a curast meter. The results are shown in Table 2.

<Examples 5, 7, 8 and Comparative Example 7>
(Procedure for preparing resin compositions K to O)
Each resin composition K to O was prepared according to the following procedure.
A master batch 1 was prepared by uniformly dispersing a part of ST-3000 as an epoxy resin (A) and Dicy15 and toluenebisdimethylurea (D) omicure 24 as dicyandiamide (C) with a three-roll mill. A master batch 2 was prepared by dispersing a part of ST-3000 as an epoxy resin (A) and Amicure PN-50 as a curing aid amine adduct (E) using a hybrid mixer. Master batch 3 was prepared by uniformly dispersing a part of ST-3000 and carbon black as an epoxy resin (A) with a three-roll mill. ST-3000 as the remaining epoxy resin (A), EHPE3150 as the epoxy resin (B), AO-50, AO-412S, and LA-31 were dissolved at 140 ° C. to prepare a master batch 4. Master batches 1, 3 and 4 were dissolved at 75 ° C., LA-62 and master batch 2 were added and mixed at 65 ° C. to obtain a resin composition.

(Preparation of resin compositions K, L, N, O)
Resin compositions K, L, N, and O were obtained by the procedure described above, with the blending amounts of resin compositions K, L, N, and O shown in Table 3. Epoxy resin compositions K, L, N, and O were injected between two pieces of glass (2 mm thickness) that had been subjected to a release treatment with a thickness of 2 mm, and heat cured under curing conditions at 130 ° C. for 2 hours. A test piece was cut out and a weather resistance test was performed. The results are shown in Table 3.

<Example 6>
The resin composition M was obtained by the above procedure with the compounding amount of the resin composition M as shown in Table 3.

As a fiber base material, TR3110M cloth manufactured by Mitsubishi Rayon Co., Ltd. was prepared. The resin film basis weight was set so that the resin content of the prepreg was 40% by mass, and the resin composition D was applied to release paper with a film coater under the condition of 65 ° C. to obtain a resin film. The obtained resin film was bonded to both sides of the fiber base material, and was subjected to a fusing press (Asahi Textile Machinery Industry Co., Ltd.) at a temperature of 80 ° C., a feed rate of 1 m / min, 0.2 MPa / 1 time and 0.4 MPa / 4 times. ), JR-600S, treatment length 1340 mm, pressure is cylinder pressure), and prepreg 1 was obtained.

Pyrofil TR391E250S prepreg manufactured by Mitsubishi Rayon Co., Ltd. was used as a molding substrate. The prepreg 1 was laminated | stacked on the outermost layer of the base material laminated | stacked so that the orientation direction of a fiber might be alternated with 0 degree and 90 degrees, cut | judged in length 298 mm x 298 mm. Using a 100 ton press manufactured by Tanaka Kamesha, a test piece was cut out from a fiber-reinforced composite material obtained by molding at 140 ° C. and 8 MPa, and a weather resistance test was performed. The results are shown in Table 3.

As shown in Table 2, the resin of the present invention can be cured for a short time.
As shown in Table 3, the resin of the present invention obtained a prepreg and a fiber-reinforced composite material having good weather resistance and capable of being cured for a short time.

Claims (12)

An epoxy resin composition comprising at least an epoxy resin (A), an epoxy resin (B), dicyandiamide (C), toluenebisdimethylurea (D), and a curing aid amine adduct (E), ) is hydrogenated bisphenol a type epoxy resins, epoxy resins der the epoxy resin (B) contains 1 to 4 groups represented by the formula (I) in a molecule,
Toluenebisdimethylurea (D) and curing aid amine adduct contained in the epoxy resin composition with respect to 100 parts by mass in total of the epoxy resin (A) and the epoxy resin (B) contained in the epoxy resin composition The epoxy resin composition whose (E) is 17.0-10.5 mass parts and 0.5-7.0 mass parts, respectively .
(N represents a natural number.) An epoxy resin composition comprising at least an epoxy resin (A), an epoxy resin (B), dicyandiamide (C), toluenebisdimethylurea (D), and a curing aid amine adduct (E), ) Is a hydrogenated bisphenol A type epoxy resin, and the epoxy resin (B) is an epoxy resin containing 1 to 4 groups represented by the formula (I) in the molecule,
For a total of 100 parts by mass of the epoxy resin (A) and the epoxy resin (B) contained in the epoxy resin composition, toluenebisdimethylurea (D) and a curing aid amine adduct ( The epoxy resin composition whose E) is 15.5-11.0 mass parts and 2.0-6.5 mass parts, respectively.
(N represents a natural number.) Furthermore, the epoxy resin composition of Claim 1 or 2 containing a ultraviolet absorber. Furthermore, the epoxy resin composition in any one of Claims 1-3 containing antioxidant. Furthermore, the epoxy resin composition in any one of Claims 1-4 containing HALS. The film which consists of an epoxy resin composition in any one of Claims 1-5 . A prepreg impregnated with the epoxy resin composition according to any one of claims 1 to 5 on a fiber substrate. A fiber reinforced composite material using a preform comprising a fiber base material and the epoxy resin composition according to any one of claims 1 to 5 . A fiber-reinforced composite material obtained by molding the prepreg according to claim 7 . A fiber-reinforced composite material using the prepreg according to claim 7 on a surface that is exposed to light. A fiber-reinforced composite material using the film according to claim 6 on a surface that is exposed to light. The fiber-reinforced composite material according to any one of claims 8 to 11 , wherein a protective film is applied to a surface that is exposed to light .