Molding material, sheet molding compound and fiber-reinforced composite material

Abstract

The present invention provides a SMC of which excessive thickening with time is suppressed while of which sufficient initial thickening by an isocyanate-based thickener is maintained, particularly of which a decrease in flowability at the time of molding to be easily actualized in the case of containing an aromatic vinyl compound such as styrene is suppressed, and which exhibits excellent storage stability and moldability, a molding material for obtaining the SMC, and a fiber-reinforced composite material using the SMC. The invention provides a molding material including: a matrix resin composition containing the following Component (A), the following Component (B), the following Component (D) and the following Component (E); and the following Component (C), in which a proportion of the Component (E) with respect to 100 parts by mass of a sum of the Component (A) and the Component (B) is 0.002 part by mass or more and 0.08 part by mass or less: Component (A): a compound having either or both of a hydroxyl group and a carboxyl group and a polymerizable unsaturated group, Component (B): an aromatic vinyl compound, Component (C): a reinforcing fiber bundle having a fiber length of 5 mm or more and 120 mm or less, Component (D): an isocyanate compound, and Component (E): a metal chelate compound.

Claims

1. A molding material comprising: a matrix resin composition comprising the following component (A), the following component (B), the following component (D) and the following component (E); and the following component (C), wherein a proportion of the component (E) with respect to 100 parts by mass of a sum of the component (A) and the component (B) is from 0.002 part by mass to 0.08 part by mass: the component (A) comprises at least one compound comprising a hydroxyl group, a carboxyl group, or a combination thereof and a polymerizable unsaturated group, the component (B) comprises an aromatic vinyl compound, the component (C) comprises a reinforcing fiber bundle having a fiber length of from 5 mm to 120 mm, the component (D) comprises an isocyanate compound, and the component (E) comprises a metal chelate compound.

2. The molding material according to claim 1, wherein the component (B) comprises styrene.

3. The molding material according to claim 1, wherein the component (A) comprises an unsaturated polyester comprising a hydroxyl group, a carboxyl group, or a combination thereof and a polymerizable unsaturated group, or an epoxy (methy)acrylate comprising a hydroxyl group, a carboxyl group, or a combination thereof and a polymerizable unsaturated group.

4. The molding material according to claim 1, wherein the component (A) comprises an unsaturated polyester comprising a hydroxyl group, a carboxyl group, or a combination thereof and a polymerizable unsaturated group, or an epoxy (methy)acrylate comprising a hydroxyl group, a carboxyl group, or a combination thereof and a polymerizable unsaturated group.

5. The molding material according to claim 1, wherein the component (C) comprises a carbon fiber bundle.

6. The molding material according to claim 1, wherein the component (E) comprises at least one metal chelate compound selected from the group consisting of a titanium chelate compound, a manganese chelate compound, an iron chelate compound, a nickel chelate compound, a copper chelate compound, a zirconium chelate compound, a tin chelate compound, and a bismuth chelate compound.

7. The molding material according to claim 1, wherein the component (E) comprises an iron chelate compound or a titanium chelate compound.

8. The molding material according to claim 7, wherein the iron chelate compound comprises iron(III) acetylacetonate.

9. The molding material according to claim 1, further comprising a polymerization initiator as a component (F).

10. The molding material according to claim 1, wherein the component (D) comprises at least one selected from the group consisting of methyl isocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate, xylene diisocyanate, and tetramethylxylylene diisocyanate.

11. The molding material according to claim 1, wherein the component (D) comprises an isocyanate prepolymer.

12. The molding material according to claim 1, wherein the component (D) comprises carbodiimide-modified MDI.

13. A method of production of the molding material according to claim 1, the method comprising: preparing a matrix resin composition by mixing components comprising the component (A), the component (B), the component (D) and the component (E); and impregnating the component (C) with the matrix resin composition.

14. A sheet molding compound comprising: a thickened product of a matrix resin composition comprising the following component (A), the following component (B), the following component (D) and the following component (E); and the following component (C), wherein a proportion of the component (E) with respect to 100 parts by mass of a sum of the component (A) and the component (B) is from 0.002 part by mass to 0.08 part by mass: the component (A) comprise at least one compound having a hydroxyl group, a carboxyl group and a polymerizable unsaturated group, or combination thereof, the component (B) comprises an aromatic vinyl compound, the component (C) comprises a reinforcing fiber bundle having a fiber length of from 5 mm to 120 mm, the component (D) comprises an isocyanate compound, and the component (E) comprises a metal chelate compound.

15. A fiber-reinforced composite material comprising a cured product of the sheet molding compound of claim 14.

16. The sheet molding compound according to claim 14, wherein the component (D) comprises at least one selected from the group consisting of methyl isocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate, xylene diisocyanate, and tetramethylxylylene diisocyanate.

17. The sheet molding compound according to claim 14, wherein the component (D) comprises an isocyanate prepolymer.

18. The sheet molding compound according to claim 14, wherein the component (D) comprises carbodiimide-modified MDI.

19. A method of production of a sheet molding material according to claim 14, the method comprising: preparing a matrix resin composition by mixing components comprising the component (A), the component (B), the component (D) and the component (E); impregnating the component (C) with the matrix resin composition; and thickening the matrix resin composition after the impregnating.

20. A method of production a fiber-reinforced composite material, the method comprising: curing the sheet molding compound according to claim 14.

Description

EXAMPLES

(1) Hereinafter, the invention will be described in detail with reference to Examples, but the invention is not limited by the description below.

(2) [Raw Materials Used]

(3) The raw materials used are presented below.

(4) (Component (A) and Mixture of Component (A) and Component (B))

(5) PEs-1: A mixture of a condensate of 2,6-naphthalenedicarboxylic acid, fumaric acid, 1,3-propanediol and ethylene glycol, which is Component (A) and styrene which is Component (B). The mass ratio is Component (A)/Component (B)=70/30.

(6) PEs-2: A mixture of a condensate of terephthalic acid, maleic acid, 1,3-propanediol and propylene glycol, which is Component (A) and styrene which is Component (B). The mass ratio is Component (A)/Component (B)=70/30.

(7) EM-1: EPDXY ESTER 3000M (trade name, manufactured by Kyoeisha Chemical Co., Ltd., methacrylic acid adduct of bisphenol A diglycidyl ether)

(8) EM-2: EPDXY ESTER 3002M (trade name, manufactured by Kyoeisha Chemical Co., Ltd., methacrylic acid adduct of bisphenol A propylene glycol adduct diglycidyl ether)

(9) EM-3: NEOPOL 8051 (trade name, manufactured by Japan U-Pica Company Ltd., a mixture of epoxy acrylate which is Component (A) and styrene which is Component (B), and the mass ratio is Component (A)/Component (B)=68/32)

(10) (Component (B))

(11) St: Styrene

(12) (Component (C))

(13) CF-C: One obtained by cutting TR50S 15L (trade name: manufactured by Mitsubishi Rayon Co., Ltd., carbon fiber bundle having filament number of 15000) to have a length of 25 mm.

(14) (Component (D))

(15) NCO: COSMONATE LL (trade name, manufactured by Mitsui Chemicals, Inc., isocyanate group-terminated urethane resin (methylene bis(4,1-phenylene) diisocyanate/polyisocyanate compound/tributyl phosphate (mass ratio)=74/24/1.2)

(16) (Component (E))

(17) E-1: Iron(III) acetylacetonate (manufactured by Sigma-Aldrich, Inc., 99.9%.)

(18) E-2: Titanium(IV) acetylacetonate (manufactured by Tokyo Chemical Industry Co., Ltd., 63% by mass isopropyl alcohol solution of tetrakis(2,4-pentanedionato)titanium(IV))

(19) (Component (F))

(20) F: 75% by mass solution of 1,1-di(t-butylperoxy)cyclohexane (manufactured by NOF CORPORATION, product name: PERHEXA C-75 (EB)).

(21) (Component (G))

(22) Milled Carbon Fiber

(23) G: milled carbon fiber having average fiber length of 40 m

(24) (manufactured by Nippon Polymer Sangyo Co., Ltd., product name: CFMP-30X)

(25) (Component (H))

(26) H: Phenyl methacrylate

(27) (manufactured by Mitsubishi Chemical Corporation, product name: Acrylic Ester PH)

Example 1

(28) (Preparation of Matrix Resin Composition)

(29) A matrix resin composition was obtained by thoroughly mixing and stirring PEs-1, F as a polymerization initiator which was Component (F), NCO as Component (D), and E-1 as Component (E) which were presented in Table 1 at 100 parts by mass (70 parts by mass of Component (A1) and 30 parts by mass of Component (B)), 1.0 part by mass, 10 parts by mass, and 0.005 part by mass, respectively.

(30) The storage stability of SMC to be obtained using the matrix resin composition was evaluated according to the [Evaluation on Storage Stability] to be described below using the matrix resin composition obtained. The results are presented in Table 1.

(31) (Manufacturing SMC)

(32) The matrix resin composition obtained was coated on a polyethylene carrier film so as to have a thickness of 1.0 mm by using a doctor blade, and CF-C as Component (C) was sprayed on this so that the basis weight of the carbon fiber bundle became substantially uniform and the directions of the carbon fibers were random. Another polyethylene carrier film coated with the same matrix resin composition so as to have a thickness of 1.0 mm was laminated on this so that the matrix resin composition sides faced each other. This was pressed by being allowed to pass through the rolls and the matrix resin composition was thus impregnated into the carbon fiber bundle, thereby obtaining an SMC precursor (molding material). The SMC precursor obtained was allowed to still stand at room temperature (23 C.) for 72 hours to sufficiently thicken the matrix resin composition in the SMC precursor, thereby obtaining a SMC. The content rate of the carbon fiber in the SMC obtained was 50% by mass, and the basis weight was 3,000300 g/m.sup.2.

(33) The flowability was evaluated using the SMC obtained. The results are presented in Table 1.

Examples 2 to 7 and Comparative Examples 1 to 3

(34) Matrix resin compositions were prepared in the same manner as in Example 1 except that the respective components presented in Table 1 were used, and the evaluation on storage stability of SMC was performed using these. The results are presented in Table 1.

(35) In addition, SMCs were fabricated in the same manner as in Example 1 using the matrix resin compositions obtained.

(36) [Evaluation on Storage Stability]

(37) The storage stability of SMC was evaluated by the viscosity measurement of the matrix resin composition which did not contain Component (C). It is possible to evaluate the storage stability of SMC by the viscosity measurement of the matrix resin composition since the storage stability is hardly affected by the presence or absence of Component (C).

(38) Specifically, in each example, the matrix resin composition after being prepared was allowed to still stand at 25 C., the viscosity of the matrix resin composition in 7 days and 70 days after the preparation was measured by using a viscometer manufactured by BROOKFIELD ENGINEERING LABORATORIES, INC., and the storage stability of SMC was evaluated according to the following criteria.

(39) (Evaluation Criteria)

(40) A: Viscosity after 70 days is less than 410.sup.4 Pa.Math.s.

(41) B: Viscosity after 70 days is 410.sup.4 Pa.Math.s or more and less than 1010.sup.4 Pa.Math.s.

(42) C: Viscosity after 70 days is 1010.sup.4 Pa.Math.s or more.

(43) [Evaluation on Flowability]

(44) The flowability at the time of press molding was evaluated using one (Sample 1) obtained by storing the SMC obtained in each example at 25 C. for 7 days and one (Sample 2) obtained by storing the SMC at 25 C. for 70 days.

(45) One sheet of Sample 1 was charged at the center of a 300 mm square die for flat plate molding and heated and compressed for 5 minutes under a condition of a die temperature of 150 C. and a pressure of 720 kN to be cured, thereby obtaining a 300 mm square fiber-reinforced composite material (CFRP molded plate) having a thickness of about 1 mm and a flat plate shape. A 300 mm square fiber-reinforced composite material (CFRP molded plate) having a flat plate shape was obtained using Sample 2 in the same manner.

(46) The change in flowability of SMC was evaluated from the ratio of the charge rate of SMC (the proportion of the SMC area in contact with the die with respect to the die area) required to obtain an intended CFRP molded plate under this molding condition.

(47) (Evaluation Criteria)

(48) A: Ratio of charge rate of Sample 2 to charge rate of Sample 1 is 100%.

(49) B: Ratio of charge rate of Sample 2 to charge rate of Sample 1 exceeds 100% and is 115% or less.

(50) C: Ratio of charge rate of Sample 2 to charge rate of Sample 1 exceeds 115%.

(51) D: Charge rate of Sample 1 exceeds 60% of die area.

(52) The composition and evaluation results of each example are presented in Table 1.

(53) Incidentally, the net amount of tetrakis(2,4-pentanedionato)titanium(IV) blended is presented in the column for E-2 in Table 1. In addition, E/D means the proportion of Component (E) with respect to 100 parts by mass of Component (D). In addition, E/(A+B) means the proportion of Component (E) with respect to 100 parts by mass of the sum of Component (A) and Component (B).

(54) TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 1 Example 2 Example 3 Component PEs-1 Component (A1) 70 28 (A) or Component (B) 30 12 mixture of PEs-2 Component (A1) 70 63 (A) and (B) Component (B) 30 27 [parts by EM-1 Component (A2) 70 42 70 mass] EM-2 Component (A2) 70 Component (A2) 68 68 68 EM-3 Component (B) 32 32 32 Component St 30 30 18 10 30 (B) [parts by mass] Component CF-C 100 100 100 100 100 100 100 100 100 100 (C) [parts by mass] Component NCO 10 10 40 40 15 15 20 15 15 40 (D) [parts by mass] Component E-1 0.050 0.050 0.050 0.050 0.050 0.020 0.001 0.100 (E) [parts by E-2 0.050 mass] Component F 1 1 1 1 1 1 1 1 1 1 (F) [parts by mass] E/D [parts try mass] 0.500 0.500 0.125 0.125 0.333 0.333 0.100 0.007 0.250 E/(A + B) [parts by mass] 0.050 0.050 0.050 0.050 0.050 0.050 0.020 0.001 0.100 Storage Viscosity After 7 days 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 stability (10.sup.4) After 70 days 4.0 4.0 4.0 4.0 4.0 6.0 3.0 10.0 10.0 Unmeasurable [Pa .Math. s] Determination B B B B B B A C C C Flowability Charge size Sample 1 220 mm square 220 mm square 220 mm square 220 mm square 220 mm square 220 mm square 220 mm square 220 mm square 220 mm square 240 mm square Sample 2 225 mm square 225 mm square 225 mm square 225 mm square 225 mm square 225 mm square 220 mm square 240 mm square 240 mm square Charge rate Sample 1 53.8% 53.8% 53.8% 53.8% 53.8% 53.8% 53.8% 53.8% 53.8% 64.0% Ratio of Sample 2/Sample 1 104.6% 104.6% 104.6% 104.6% 104.6% 109.3% 100.0% 119.0% 119.0% charge rate Determination B B B B B B A c c D

(55) As presented in Table 1, in Examples 1 to 7 in which Component (E) was blended at the proportion regulated in the invention, excessive thickening of SMC with time was suppressed as the viscosity of the matrix resin composition in 70 days after the preparation was lower than those of Comparative Example 2 in which the proportion of Component (E) was too small, Comparative Example 3 in which the proportion of Component (E) was too great, and Comparative Example 1 in which Component (E) was not contained. In addition, the SMCs of Examples 1 to 7 exhibited higher flowability than the SMCs of Comparative Examples 1 to 3.