RESIN COMPOSITIONS FOR LIQUID RESIN INFUSION AND APPLICATIONS THEREOF

Abstract

A resin infusion method that includes: (a) heating a mixture of solid amine compounds until all amine compounds are melted; (b) cooling the mixture of melted amine compounds to a temperature of 35 C. or lower to form an amine blend (A); (c) combining the amine blend (A) with a thermosettable resin (B), which includess one or more epoxy monomers, at a temperature effective for forming a liquid resin composition; and (d) infusing a fibrous preform with the liquid resin composition. The amine blend (A) contains an aromatic diamine represented by Structure 1 or 2:

##STR00001##

Claims

1. A resin infusion method comprising: a) heating a mixture of solid amine compounds until all amine compounds are melted; b) cooling the mixture of melted amine compounds to a temperature of 35 C. or lower, preferably, in the range of 20 C. to 35 C. to form an amine blend (A); c) combining the amine blend (A) with a thermosettable resin (B), which comprises one or more epoxy monomers, at a temperature effective for forming a liquid resin composition; and d) infusing a fibrous preform with the liquid resin composition, wherein the mixture of solid amine compounds at (a) comprises at least three amine compounds, at least one of which is an aromatic diamine having an individual melting point (T.sub.m1) and represented by Structure 1 or 2: ##STR00007## and the other amine compounds are aromatic diamines having an original individual melting point (T.sub.m2), which is higher than T.sub.m1.

2. The method of claim 1, wherein the amine blend (A) has a T.sub.g of 50 C. to 150 C. or 0 C. to 30 C., as determined by Differential Scanning calorimetry (DSC) at ramp rate of 5 C./min.

3. The method of claim 1, wherein T.sub.m2 is in the range of 130 C. to 250 C. as determined by DSC at ramp rate of 5 C./min.

4. The method according to claim 1, wherein the aromatic diamines with melting point T.sub.m2 are selected from the following Structures 3 to 6: ##STR00008##

5. The method according to claim 4, wherein the amine blend (A) is selected from the following combinations: (i) Structure 1 and/or Structure 2 in combination with Structure 3 and Structure 4; (ii) Structure 1 and/or Structure 2 in combination with Structure 5 and Structure 6; (iii) Structure 1 and/or Structure 2 in combination with at least one of Structures 3 and 4 and at least one of Structures 5 and 6.

6. The method according to claim 4, wherein the amine blend (A) comprises the aromatic diamine Structure 1 or Structure 2 in combination with the aromatic diamines of Structures 3 to 6.

7. The method according to claim 4, wherein the amine blend (A) comprises the aromatic diamine of Structure 1 or Structure 2 in combination with the aromatic diamines of Structures 3, 4 and 5.

8. The method according to claim 4, wherein the amine blend (A) comprises the aromatic diamine of Structure 1 or Structure 2 in combination with the aromatic diamines of Structures 3, 4 and 6.

9. The method according to claim 4, wherein the amine blend (A) comprises the aromatic diamine of Structure 1 and/or Structure 2 in combination with the aromatic diamines of Structure 3 or 4, and Structure 5 or 6.

10. The method according to claim 4, wherein the amine blend (A) comprises the aromatic diamine of Structure 1 and/or Structure 2 in combination with the aromatic diamines of Structures 3 and 4.

11. The method according to claim 4, wherein the amine blend (A) comprises the aromatic diamine of Structure 1 and/or Structure 2 in combination with the aromatic diamines of Structure 3 or 4, and Structures 5 and 6.

12. The method according to claim 1, wherein the amine blend (A) and the resin (B) are mixed ata weight ratio (A:B) of 1:9 to 9:1, or 30:70 to 50:50.

13. The method according to claim 1, wherein the amine blend (A) and the resin (B) are mixed at a weight ratio (A:B) of 1:1.

14. The method according to claim 1, wherein, at (a), the mixture of solid amine compounds melt at a depressed temperature (T.sub.d) that is lower than T.sub.m2.

15. The method according to claim 14, wherein the depressed temperature (T.sub.d) is lower than 170 C.

16. The method according to claim 1, wherein the amine blend (A) is in a glassy, amorphous phase at a temperature in the range of 20 C. to 35 C.

17. The method according to claim 1, further comprising: placing the fibrous preform in a closed mold and heating the mold prior to injecting the liquid resin composition into the mold to affect infusion of the liquid resin composition into the preform.

18. (canceled)

19. The method of claim 17, wherein the liquid resin composition has a viscosity of less than 10 Poise, at a temperature in the range of 90 C. to 160 C. during injection into the mold.

20. The method according to claim 17, further comprising raising the temperature of the mold after resin infusion is completed to affect curing of the resin-infused preform, thereby forming a hardened composite article.

21. A two-component resin system for liquid resin infusion, comprising: (A) an amine blend of at least three different amine compounds; and (B) a thermosettable resin comprising one or more epoxy monomers, wherein components (A) and (B) are physically separated from each other, and are combinable to form a substantially homogenous resin composition, and wherein at least one of the amine compounds of component (A) is an aromatic diamine represented by Structure 1 or 2: ##STR00009## and the other amine compound is an aromatic diamines selected from Structures 3-6: ##STR00010##

22-25. (canceled)

Description

EXAMPLES

Example 1

[0043] Different amine blends were formed from APB133, APB144, 3,3-DDS, 4,4-DDS, CAF and AF, at the weight ratios shown in Table 1.

TABLE-US-00001 TABLE 1 T.sub.g of AF T.sub.m of blend blend Blend ID APB144 APB133 33DDS 44DDS CAF (no Cl) ( C.) ( C.) #7 6.3 43.4 11.8 38.6 158 14 #11 46.4 47.6 2.2 3.8 112 12 #39 50 9.2 3.9 37 185 5 #49 8.9 43.5 35.4 12.2 190 47 #50 3.0 46.0 7.0 4.0 39.0 212 38

[0044] In Table 1, T.sub.m refers to melting point of the blend. The amine compounds, initially in solid form, were mixed at room temperature (20 C.-25 C.). Powder blends of the amine mixtures were prepared using pestle and mortar. A DSC was run on the blended amines to determine the temperature at which the blends should be thermally treated to obtain a glassy material. The powder was compacted gently to allow thermal conductivity and place in an oven at a temperature higher than their melting point, 170 C. or 190 C., for an hour or at (1) analyzed by DSC to determine their melting point, (2) maintained for 1 hour at the temperature defining the end of the melting peak (about 170 C.-190 C.). The diamine blends was re-analyzed by DSC at ramp rate of 5 C./min after thermal treatment, looking at eventual re-crystallisation (>10 J/g) phenomenon or residual melt (<10 J/g).

Example 2

[0045] An amine mixture (Composition E) was prepared according to the formulation shown in Table 2.

TABLE-US-00002 TABLE 2 Components Weight % 3,3DDS 21.65 4,4DDS 21.65 CAF 3.3 APB133 50.0 AF 3.4

[0046] The amine mixture was heated in a steel can with stirring at the preparation temperature of 140 C. for 20 minutes and then the mixture is allowed to cool to room temperature.

[0047] An epoxy-based resin composition composed of multifunctional epoxy resins (PY 306, MY 0510, MY 0610, and MY 721 from Huntsman), PES, and core-shell rubber particles was prepared. Pre-warming of the amine mixture (curative component) and the resin composition (resin component) was carried out separately, then each component was degassed for 45 minutes. The two components were combined in a 1:1 weight ratio and stirred. The resulting mixture was then degassed at 80 C. for a further 5 minutes and then transferred into a resin pot for VaRTM processing.

[0048] 196 gsm Plain Weave carbon fabric was used to form a quasi isotropic layup [+,0, , 90].sub.3s, which was then used as a preform for resin infusion. Upon successful resin infusion of the preform at 80 C., the resin-infused preform was cured for 2 hrs at 180 C. following a 2 C./min ramp from 80 C.