PREPREG, MOLDED ARTICLE AND EPOXY RESIN COMPOSITION

Abstract

Provided are a prepreg and an epoxy resin composition that can shorten the combustion time of a molded article. The present invention comprises a prepreg which is formed by impregnating a carbon fiber base material with an epoxy resin composition, wherein the epoxy resin composition comprises component (A): an organic phosphinate metal salt, component (B): an epoxy resin having an oxazolidone structure, and component (C): an imidazole compound or an imidazole compound derivative, and may comprise component (D) a urea compound.

Claims

1. A prepreg formed by impregnating a carbon fiber base material with an epoxy resin composition, wherein the epoxy resin composition comprises component (A), component (B), component (C), and component (D); Component (A): an organic phosphinate metal salt, Component (B): an epoxy resin having an oxazolidone structure represented by Formula (2), ##STR00006## (In Formula (2), n and in are each independently an integer of 0 or more and Y represents a divalent group which may have a substituent group, 7 represents a 5- to 8-membered cycloalkanediyl group having at least one substituent group selected from an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 6 to 10 carbon atoms, or represents an alkylene group having 1 to 8 carbon atoms. R.sup.4 is each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, or an aralkyloxy group having 6 to 10 carbon atoms.), Component (C): an imidazole compound or an imidazole compound derivative, Component (1)): a urea compound.

2. The preg according to claim 1, wherein the epoxy resin composition further comprises component (F); Component (E): a dicyandiamide or a dicyandiamide derivative.

3. The prepreg according to claim 1, wherein the epoxy resin composition further comprises component (F); Component (F): at least one type of epoxy resin selected from novolac-type epoxy resins, naphthalene-type epoxy resins, and biphenyl-type epoxy resins.

4. The prepreg according to claim 1, wherein the component (A) is an organic phosphinate metal salt represented by Formula (1), ##STR00007## (in Formula (1), R.sup.1 and R.sup.2 are each independently an alkyl group or an aryl group, M is at least one type selected from the group consisting of Me, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Ni, Li, K, and Na, and in represents an integer of 1 to 4).

5. The prepreg according to claim 4, wherein R.sup.1 and R.sup.2 are alkyl groups, M is Al, and m is 3 in Formula (I).

6. The prepreg according to claim 1, wherein a mass ratio of the component (A) to the component (B) (component (A)/component (B)) comprised in the epoxy resin composition is 0.05 to 0.5.

7. The prepreg according to claim 1, wherein the component (A) is comprised as 1 to 25 parts by mass with respect to 100 parts by mass of the epoxy resin composition.

8. The prepreg according to claim 1, wherein the component (B) is comprised as 20 to 50 parts by mass with respect to 100 parts by mass of the epoxy resin composition.

9. The prepreg according to claim 1, wherein the component (C) is comprised as 1 to 30 parts by, mass with respect to 100 parts by mass of the epoxy resin composition.

10. The prepreg according to claim 1, wherein the component (D) is at least one type of compound selected from the group consisting of phenyldimethylurea, methylenebis(phenyldimethylurea), and tolylenebis(dimethylurea).

11. A molded article formed by curing the prepreg according to claim 1.

12. An epoxy resin composition comprising component (A), component (B), component (C), and component (D): Component (A): an organic phosphinate metal salt, Component (B): an epoxy resin having an oxazolidone structure, Component (C): an imidazole compound or an imidazole compound derivative, Component (D): a urea compound.

13. The epoxy resin composition according to claim 12, further comprising: component (E); Component (E): a dicyandiamide or a dicyandiamide derivative.

14. The epoxy resin composition according to claim 12, further comprising: component (F); Component (F): at least one type of epoxy resin selected from novolac-type epoxy resins, naphthalene-type epoxy resins, and biphenyl-type epoxy resins.

15. The epoxy resin composition according to claim 12, wherein the component (A) is an organic; phosphinate metal salt represented by Formula (1), ##STR00008## (in Formula (1), R.sup.1 and R.sup.2 are each independently an alkyl group or an aryl group, M is at least one type selected from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Ni, Li, K, and Na, and m represents an integer of 1 to 4).

16. The epoxy resin composition according to claim 15, wherein R.sup.1 and R.sup.2 are aryl groups, M is Al, and m is 3 in Formula (1).

12. epoxy resin composition according to claim 12, wherein a mass ratio of the component (A) to the component (B) (component (A)/component (B)) comprised in the epoxy resin composition is 0.05 to 0.5.

18. The epoxy resin composition according to claim 12, wherein the component (A) is comprised as 1 to 25 parts by mass with respect to 100 parts by mass of the epoxy resin composition.

19. The epoxy resin composition according to claim 12, wherein the component (B) is comprised as 20 to 50 parts by mass with respect to 100 parts by mass of the epoxy resin composition.

20. The epoxy resin composition according to claim 12, wherein the component (C) is comprised as 1 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin composition.

Description

EXAMPLES

[0213] A specific, description will be given below of the present invention with reference to Examples, but the present invention is not limited thereto. The raw materials used in the Examples and Comparative Examples are shown below.

[0214] [Material]

[0215] <Component (A)> [0216] OP-935: Trisdiethylphosphinate aluminum salt, phosphorus atom content 23.0% by mass, average particle size 2 to 3 μm, maximum particle size less than 10 μm, “Exolit OP935” manufactured by Clariant Japan Co., Ltd.

[0217] <Component (B)>

[0218] YD952: Oxazolidone-type epoxy resin, “YD-952” remanufactured by Nippon Steel Chemical & Material Co., Ltd. In Formula (2), there is contained a compound having a structure in which Z is —C(CH.sub.3).sub.2—, R.sup.4 is a hydrogen atom, ne and n are 0, and Y is a group represented by (2a).

[0219] <Component (C)> [0220] 2MZA-PW: 2,4-diamino-6[2′-methylimidazolyl-(1′)]-ethyl-s-triazine, “2MZA-PW” manufactured by Shikoku Chemicals Corporation.

[0221] <Component (D)> [0222] Omicure94: Phenlydimethylurea, “Omicure94” manufactured by PTI Japan Ltd.

[0223] <Component (E)> [0224] Dicyanex1400F: Dicyandiamide, “Dicyanex1400F” manufactured by Evonik Japan Co., Ltd. [0225] DICY15: Dicyandiamide, “jER Cure DICY15” manufactured by Mitsubishi Chemical Corp.

[0226] <Component (F)> [0227] YDPN638: Phenol novolac-type epoxy resin, epoxy equivalent 180 g/eq, “YDPN-638” manufactured by Nippon Steel Chemical & Material Co., Ltd. [0228] N-690: Cresol novolac-type epoxy resin, epoxy equivalent 214 g/eq, “N-690” manufactured by DIC Corp.

[0229] <Others> [0230] HP-1134770: Naphthalene type epoxy resin, epoxy equivalent 204 g/eq, “HP-4770” manufactured by DIC Corp. [0231] NC3000: Biphenyl type epoxy resin, epoxy equivalent 265 to 285 g/eq, “NC-3000” manufactured by Nippon Kayaku Co., Ltd. [0232] jER604: N,N,N′,N′-tetraglycidyldiaminodiphenylmethane, epoxy equivalent 120 g/eq, “jER 604” manufactured by Mitsubishi Chemical Corp. [0233] jER828: Liquid bisphenol A type epoxy resin, epoxy equivalent 189 g/eq, “jER 828” manufactured by Mitsubishi Chemical Corp. [0234] YD128: Liquid bisphenol A type epoxy resin, epoxy equivalent 189 g/eq, “YD-128” manufactured by Nippon Steel Chemical & Material Co., Ltd. [0235] jER807: Liquid bisphenol F type epoxy resin, epoxy equivalent 168 g/eq, “jER 807” manufactured by Mitsubishi Chemical Corp. [0236] TOP: Tricresyl phosphate, “TOP” manufactured by Daihachi Chemical Industry Co., Ltd.

[0237] <Carbon Fibers> [0238] Carbon fibers: “PYROFIL TR50S15L” manufactured by Mitsubishi Chemical Corp.

Examples 1 to 5, Experimental Examples 1 to 6

[0239] According to each of the formulations shown in Table 1, jER 828 and jER 807 (liquid) and the component (E) (solid), the component (D) (solid), and the component (C) (solid) were weighed into a container such that the solid components and the liquid components had a mass ratio of 1:1, stirred, and mixed. The above were further finely mixed in a three-roll mill to obtain a curing agent master batch. Subsequently, among the formulations shown in Table 1, components other than the component (A) and the curing agent master batch were weighed into a flask, heated to 120° C. using an oil bath, and dissolved and mixed. Thereafter, while cooling to approximately 65° C., the component (A) was added thereto, stirred, mixed, and then when cooled to approximately 65° C., the curing agent master batch was added thereto, stirred, and mixed to obtain an epoxy resin composition.

[0240] Using the obtained epoxy resin composition, a resin plate was produced according to the method for producing an epoxy resin plate described below. In addition, various measurements and evaluations were performed according to the evaluation methods described below. Table 2 shows the results.

[0241] [Method for Producing Epoxy Resin Plate]

[0242] After curing the uncured epoxy resin composition at an oven atmosphere temperature of 70° C. for 10 minutes, curing was carried out at 140° C. for 40 minutes (heating rate: 10° C./min) to produce a resin plate with a thickness of 2 mm.

[0243] [Evaluation Method]

[0244] UL-94V Combustion Test of Resin Plate

[0245] The resin plate with a thickness of 2 mm obtained by the epoxy resin plate production method was processed into a length of 127 mm and a width of 12.7 mm to obtain a test piece, The test piece was subjected to a combustion test according to the UL-94V standard using a combustion tester (manufactured by Suga Test instruments Co., Ltd.). Specifically, the test piece was vertically attached to a clamp, subjected to flame contact with a 20 mm flame for 10 seconds, and the combustion time was measured. A combustion test was performed on five test pieces and the number of samples that combusted up to the clamp, the maximum value (max) of each combustion time, and the sum of the five combustion times (total combustion time: total) were recorded.

[0246] Calculation of Curing Time

[0247] The torque value of the uncured epoxy resin composition of Example 5 as continuously measured using a Curlastometer (manufactured by JSR Trading Co., Ltd., “Curlastorneter 7 (Type P)”) and, by determining the change in the viscoelastic stress during the curing reaction, the degree of curing and the curing time were measured. The time for obtaining a torque value of 90% of the maximum torque value was set as the complete curing time. The complete curing time was 3.7 minutes.

[0248] [Production of Prepreg]

[0249] A prepreg was obtained by impregnating carbon fibers aligned in one direction with the resin composition produced in Example 1. The obtained prepreg had appropriate tackiness and hardness and was excellent in workability. The prepreg had a carbon fiber areal weight of 125 g/m.sup.2 and a resin content of 40% by mass.

[0250] [Production of Plate Formed of Fiber-Reinforced Composite Material]

[0251] The obtained prepreg was cut to 300 mm×300 mm and laminated by the hand layup method. Each of the prepreg layers were laminated such that the longitudinal directions of the reinforcing fibers were perpendicular to each other. The curing conditions were 130° C. for 90 minutes (heating rate: 2° C./min) using an autoclave. A plate formed of a fiber-reinforced composite material (fiber-reinforced composite material plate) having a thickness of 0.5 mm was produced.

[0252] [UL-94V Combustion Test of Fiber-Reinforced Composite Material]

[0253] A test piece formed by processing the obtained fiber-reinforced composite material plate having a thickness of 0.5 mm into a length of 127 mm and a width of 12.7 mm was subjected to a combustion test using a combustion tester (manufactured by Suga Test Instruments Co., Ltd.) in accordance with UL-94V standards. Specifically, the test piece was vertically attached to a clamp, subjected to flame contact with a 20 mm flame for 10 seconds, and the combustion time was measured. A combustion test was performed on five test pieces and the number of samples that combusted up to the clamp, the maximum value (max) of each combustion time, and the sum of the five combustion times (total combustion time: total) were recorded.

[0254] The results are shown in Table 3.

TABLE-US-00001 TABLE 1 Experi- Experi- Experi- Experi- Experi- Experi- Exam- mental mental mental mental mental mental Exam- Exam- Exam- Exam- Product ple Example Example Example Example Example Example ple ple ple ple Component No. 1 1 2 3 4 5 6 2 3 4 5 Component OP-935 7 7 7 0 0 7 7 7 8 8 4 (A) Component YD952 31 0 0 34 33 31 31 29 33 33 35 (B) Component 2MZA-PW 6 6 6 7 6 0 6 6 6 6 6 (C) Component Omicure94 2 2 2 2 2 1 0 1 2 2 2 (D) Component Dicyanex1400F 0 0 0 0 8 0 0 0 0 0 7 (E) DICY15 7 7 7 8 0 7 2 6 7 7 0 Component YDPN638 0 0 0 0 19 18 22 17 0 0 20 (F) N-690 0 31 0 0 0 0 0 0 0 0 0 HP4770 0 0 0 0 0 0 0 0 19 0 0 NC3000 0 0 0 0 0 0 0 0 0 19 0 Other jER604 0 0 31 0 0 0 0 0 0 0 0 jER828 0 0 0 0 19 18 0 17 0 0 20 YD128 0 0 0 0 6 17 0 16 25 25 6 jER807 47 47 47 50 0 0 32 0 0 0 0 TOP 0 0 0 0 8 0 0 0 0 0 0

TABLE-US-00002 TABLE 2 Experi- Experi- Experi- Experi- Experi- Experi- Exam- mental mental mental mental mental mental Exam- Exam- Exam- Exam- Product ple Example Example Example Example Example Example ple ple ple ple Component No. 1 1 2 3 4 5 6 2 3 4 5 Component OP-935 7 7 7 0 0 7 7 7 8 8 4 (A) Component YD952 31 0 0 34 33 31 31 29 33 33 35 (B) Component 2MZA-PW 6 6 6 7 6 0 6 6 6 6 6 (C) Component Omicure94 2 2 2 2 2 1 0 1 2 2 2 (D) Resin plate max1, 2 4 10 4 67 85 9 59 3 2 1 3 UL-94 total 9 32 16 230 419 40 241 9 5 5 12 Combustion test

TABLE-US-00003 TABLE 3 Component Product No. Example 1 Component (A) OP-935 7 Component (B) YD952 31 Component (C) 2MZA-PW 6 Component (D)) Omicure94 2 Fiber-reinforced max1, 2 3 composite material total 12 UL-94 Combustion test

[0255] As is clear from the results in Table 2, the resin plates of Examples 1 to 5 had excellent flame retardancy, with a total combustion test time of 10 seconds or less, or around 10 seconds, It is considered that, in Examples 1 to 5, the epoxy groups were activated by the component (B) and the component (C) included in the epoxy resin composition and the cross-linking density of the epoxy resin composition was adequately increased, such that it was possible to uniformly disperse the component (A) and to obtain high flame retardancy.

[0256] From the results in Table 3, it is understood that, in the combustion test of the fiber-reinforced composite material, the values of max 1 and 2 were smaller than in the combustion test of the resin plate and high flame retardancy was obtained even with the fiber-reinforced composite material. It is considered that the fiber-reinforced composite material contain fibers that inhibit uniform dispersion of the component (A) and form easily combustible parts, such that the combustion progresses more easily than in the resin plate, resulting in inferior combustion tests. However, in Example 1, even with the fiber-reinforced composite material, it was possible to sufficiently suppress the progress of the combustion. On the other hand, the resin plates of Experimental Example 1 not including the component (B), Experimental Example 2 including a polyfunctional epoxy resin without including the component (B), Experimental Example 3 not including the component (A), Experimental Example 4 including a phosphoric acid ester instead of the component. (A), Experimental Example 5 not including the component (C), and Experimental Example 6 not including the component (D) were all Inferior in flame retardancy in comparison with the resin plates of the Examples.

[Industrial Applicability]

[0257] According to the present hive ion, it is possible to provide an epoxy resin composition and a prepreg that have excellent flame retardancy, and a molded article and a fiber-reinforced composite material that have excellent flame retardancy and a favorable external appearance, which are obtained using the epoxy resin composition and the prepreg.