Epoxy resin compositions

Abstract

An epoxy resin composition [composition (C)] comprising: (i) from 30 to 90% by weight of at least one epoxy compound [compound E], based on the total weight of the composition (C); (ii) from 0 to 60% by weight of at least one curing agent [agent C], based on the total weight of the composition (C); (iii) from 0 to 15% by weight of at least one accelerator, based on the total weight of the composition (C); (iv) from 1 to 60% by weight of at least one poly(aryl ether sulfone) (I) [PAES (I-1)], based on the total weight of the composition (C) and wherein said PAES (I-1) polymer comprises amine functional groups in an amount equal to or more than 200 eq/g; (v) from 1 to 60% by weight of at least one poly(aryl ether sulfone) (I) [PAES (I-2)], based on the total weight of the composition (C), and wherein said PAES (I-2) polymer is different from the PAES (I-1) polymer.

Claims

1. An epoxy resin composition (C), comprising: (i) from 30 to 90% by weight of at least one epoxy compound (E), based on the total weight of the composition (C); (ii) from 0 to 60% by weight of at least one curing agent, based on the total weight of the composition (C); (iii) from 0 to 15% by weight of at least one accelerator, based on the total weight of the composition (C); (iv) from 1 to 60% by weight of at least one first poly(aryl ether sulfone) polymer (PAES (I-1)), based on the total weight of the composition (C) and wherein said PAES (I-1) polymer comprises amine functional groups in an amount equal to or more than 200 eq/g; and (v) from 1 to 60% by weight of at least one second poly(aryl ether sulfone) polymer (PAES (I-2)), based on the total weight of the composition (C), and wherein said PAES (I-2) polymer is different from the PAES (I-1) polymer and the PAES (I-2) polymer is a polyethersulfone of which more than 50% by weight of the recurring units are recurring units according to formula (K): ##STR00014## and the PAES (I-2) polymer comprises phenol OH functional groups in an amount equal to or more than 10 eq/q.

2. The composition (C) according to claim 1, wherein more than 50% wt of the recurring units of the PAES (I-1) polymer are recurring units (R) according to formula (A):
Ar.sup.1-(T-Ar.sup.2).sub.nOAr.sup.3SO.sub.2[Ar.sup.4-(T-Ar.sup.2).sub.nSO.sub.2].sub.mAr.sup.5O(A) wherein: Ar.sup.1, Ar.sup.2, Ar.sup.3, Ar.sup.4, and Ar.sup.5 are equal to or different from each other and, at each occurrence, independently an aromatic mono- or polynuclear group; T and T are equal to or different from each other and, at each occurrence, independently a bond or a divalent group and may optionally comprise one or more than one heteroatom; and n and m, equal to or different from each other, are independently zero or an integer of 1 to 5.

3. The composition (C) according to claim 2, wherein recurring units (R) are selected from formulae (B) to (D): ##STR00015## wherein: each of R, equal to or different from each other, is selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium; j is zero or is an integer from 0 to 4; T and T, equal to or different from each other, is selected from the group consisting of a bond, CH.sub.2; O; SO.sub.2; S; C(O); C(CH.sub.3).sub.2; C(CF.sub.3).sub.2; C(CCl.sub.2); C(CH.sub.3)(CH.sub.2CH.sub.2COOH); NN; R.sup.aCCR.sup.b; where each R.sup.a and R.sup.b; independently of one another, is a hydrogen or a C.sub.1-C.sub.12-alkyl, C.sub.1-C.sub.12-alkoxy, or C.sub.6-C.sub.18-aryl group; (CH.sub.2).sub.n and (CF.sub.2).sub.n with n=integer from 1 to 6, or an aliphatic divalent group, linear or branched, of up to 6 carbon atoms; and mixtures thereof.

4. The composition (C) according to claim 1, wherein the PAES (I-1) polymer is a bisphenol A polysulfone polymer of which more than 50% by weight of the recurring units are recurring units according to formula (M): ##STR00016##

5. The composition (C) according to claim 1, wherein the PAES (I-1) polymer has 200-800 eq/g of amine functional groups.

6. The composition (C) according to claim 1, wherein the PAES (I-1) polymer further comprises functional groups different from amine functional groups and wherein the amine functional groups and the functional groups different from amine functional groups are present in a ratio of from about 10:1 to about 1:1.

7. The composition (C) according to claim 1, wherein the PAES (I-1) polymer has a weight average molecular weight in the range from 3000 to 40,000 grams per mole and glass transition temperature of 180 to 270 C.

8. The composition (C) according to claim 1, wherein the PAES (I-2) polymer has a weight average molecular weight in the range from 10,000 to 55,000 grams per mole and glass transition temperature of 100 to 220 C.

9. A process for manufacturing the composition (C) according to claim 1, comprising mixing: the at least one epoxy compound E, the at least one PAES (I-1) polymer, the at least one PAES (I-2) polymer, optionally, the at least one curing agent, and optionally, the at least one accelerator.

10. A process for making a cured compound from the composition (C) according to claim 1, comprising mixing and heating the at least one epoxy compound E, the at least one PAES (I-1) polymer, the at least one PAES (I-2) polymer, the at least one curing agent, optionally, the at least one accelerator, and optionally, at least one other ingredient.

11. A process for making a cured compound, comprising processing the composition (C) according to claim 1 by resin transfer molding, continuous resin transfer molding, vacuum assisted resin transfer molding, vacuum assisted injection moulding, vacuum assisted processing, vacuum infusion moulding, vacuum bag curing, press molding, Seeman Composite resin infusion, resin film infusion, resin infusion under flexible tooling, automated fiber placement, filament winding, pultrusion, or thermal expansion molding.

12. A cured compound made by the process according to claim 10.

13. An article comprising the cured compound according to claim 12 wherein the article is an aircraft structural component, a secondary aircraft component, an automotive structural component, oil well lining tubes, a power transmission tube, a printed circuit board, a rail component, or a wind power generation component.

Description

PREPARATIVE EXAMPLE 1

Synthesis of Benzoaxine End Capped Resin #2 (Resin #4, Hereafter)

(1) ##STR00013##

(2) In a 500 ml round bottom flask was placed 13.41 g of amine-terminated polysulfone (B2) along with 60 ml dioxane. The mixture was stirred for five minutes to give a clear, dark solution. Next, 0.28 g paraformaldehyde and 1.25 g -naphthol were added and the contents warmed to reflux for six hours. The mixture was poured into a Waring blender containing 1 L deionized water at 80 C. and mixed for one minute. The slurry was filtered, the solid washed with methanol and dried in a vacuum oven at 90 C. for fifteen hours. HNMR analysis of the solid in CDCl.sub.3 revealed peaks at 5.46 and 4.94 ppm characteristic of the benzoxazine ring.

PREPARATIVE EXAMPLE 2

Synthesis of Dianhydride End Capped Resin #1 (Resin #5, Hereafter)

(3) Into a 250-ml four-neck flask equipped with an overhead stirrer, Dean Stark trap, condenser, nitrogen inlet, and thermocouple, was placed 20.0 g Virantage VW-10200 RFP, 0.88 g (0.0151 mol) KF, 1.8 g (0.011 mol) 4-fluorophthalic anhydride, and 70 mL 2-methylpyrrolidone. The mixture was stirred and warmed to 180 C. for three hours. The mixture was cooled to 40-80 C., filtered through a glass fiber filter, and poured in to an excess of methanol to form a solid. After filtration, the polymer powder was washed twice with water and then with methanol. The solid was dried under reduced pressure at 130 C. overnight.

PREPARATIVE EXAMPLE 3

Synthesis of a Low Weight Average Molecular Weight Polyethersulfone (Mw 11,400 g/mole) Having Phenol OH Groups (Resin #6, Hereafter)

(4) In a 500 ml 4-neck flask equipped with an overhead stirrer, Dean Stark trap, condenser, nitrogen inlet, and thermocouple, was placed 27.54 g (0.0959 moles) dichlorodiphenylsulfone, 30.00 g (0.1198 moles) bisphenol S, 24.85 g (0.18 moles) potassium carbonate, and 117 g sulfolane. The mixture was warmed under a slight stream of nitrogen to 210 C. and held at that temperature for 24 hours. The mixture was cooled to 50 C. and poured in to acidified methanol to form a white solid. The solid was isolated by filtration, washed with methanol, and dried in a vacuum oven overnight at 130 C.

PREPARATIVE EXAMPLE 4

Synthesis of Dianhydride Endcapped Resin (Resin #7, Hereafter)

(5) Into a 250-ml four-neck flask equipped with an overhead stirrer, Dean Stark trap, condenser, nitrogen inlet, and thermocouple, was placed 10.0 g, of resin #6 of preparative example 3, 0.44 g (0.0075 mol) KF, 0.90 g (0.005 mol) 4-fluorophthalic anhydride, and 70 mL 2-methylpyrrolidone. The mixture was stirred and warmed to 180 C. for three hours. The mixture was cooled to 40-80 C., filtered through a glass fiber filter, and poured in to an excess of methanol to form a solid. After filtration, the polymer powder was washed twice with water and then with methanol. The solid was dried under reduced pressure at 130 C. overnight.

PREPARATIVE EXAMPLE 5

Synthesis of a Medium Weight Average Molecular Weight Polyethersulfone (Mw 24,000 g/mole) Having COOH Groups (Resin #8, Hereafter)

(6) In a 500-ml four-neck flask equipped with an overhead stirrer, Dean Stark trap, condenser, nitrogen inlet, and thermocouple, was placed 29.1 g (0.116 mol) bisphenol S, 2.49 g (0.0181 mol) p-hydroxybenzoic acid, 27.36 g (0.198 mol) K.sub.2CO.sub.3, 35.9 g 4,4-dichlorodiphenylsulfone, and 125 g sulfolane. The reaction mixture was warmed to 210 C. under a slight stream of nitrogen for four hours. The mixture was cooled to about 150 C. and diluted with about 100 ml sulfolane. After further cooling, the mixture was filtered through a glass fiber filter to remove inorganic salts and the resulting solution added to an excess of methanol. The solid was isolated by filtration and washed with warm water twice and finally with methanol. The solid was then dried under reduced pressure at 100 C. overnight.

(7) General Procedure for the Preparation of an Epoxy Resin Composition in Solution

(8) The epoxy resin composition in solution was prepared in an oven-dried 50-mL wide mouth jar by adding 20.000.02 g (80 wt. %) triglycidyl p-aminophenol (TGAP) liquid to a total amount of 5.00 g (20 wt. %) of a PAES polymer or a PAES polymer mixture in powder form and oven-dried. The jar was placed in an oil bath controlled at 130 C. and the mixture was stirred for 15-30 minutes vigorously with a glass rod until a homogeneous mixture was observed. Next, the open jar was placed in a vacuum oven at 90 C. for one hour to degas the yellow-brown clear solutions.

(9) Weight fractions of the various resins in the PAES polymer mixture, solution viscosity of the epoxy resin composition in solution is summarized in table 2.

(10) Solution Viscosity Test Method:

(11) The viscosities of the epoxy resin composition solution, as detailed above, were measured using a Haake VT-500 viscometer with the HV-1 spindle and cup. The temperature was controlled at 60.00.1 C. using a Yamato Thermoelite Model BH-71 temperature controlled water bath. A portion of the warm epoxy resin composition solutions was poured in to the HV-1 cup until the cavity was filled and then the spindle pushed in to the cavity and solution so that a small amount of the solution completely covered the measuring volume. The spindle and cup were attached to the VT-500 viscometer and the sample was equilibrated at 60.0 C. for 15 minutes. The viscometer was zeroed and the spindle turned at speeds to give torque readings between 0.10 and 2 N-cm which was the range of this instrument. The torque readings (M.sub.d, N-cm) were recorded at various speed settings (n). The viscosity (, Pa.Math.s) was calculated using the equations below and the shape factors (f and M) for the HV-1 spindle and cup supplied in the Haake VT-500 manual.

(12) Shear stress ()=M.sub.df/10 (Pa)

(13) Shear rate (D)=nM/1000 (1/s)

(14) Viscosity ()=/D (Pa.Math.s)

(15) Where f=25275 and M=1290 for the HV-1 rotor and cup.

(16) General Procedure for the Preparation of a Cured Epoxy Resin Composition

(17) In an 8-ounce wide mouth jar was weighed 100 parts (54.4 wt. %) of triglycidyl p-aminophenol (TGAP). Next, 50 g of methylene chloride was added and the mixture stirred for a few minutes at room temperature using a PTFE-coated magnetic stir bar. To this solution was added 40 parts (21.7 wt. %) of a PAES polymer or a PAES polymer mixture in powder over 10 minutes. The mixture was stirred for an additional 15 minutes to give a clear solution. Next, 44 parts (23.9 wt. %) of 4,4-diaminodiphenylsulfone (DDS) hardener was added and the milky suspension stirred for 30 minutes. The suspension was poured into a 10 cm diameter PTFE dish on a hot plate controlled at 60C. After one hour, the PTFE dish and the viscous epoxy resin composition mixture was placed in a vacuum oven at 55 C. for 16 hours, and then warmed to 120 C. under vacuum for one hour. The vacuum was released and the mixture heated an additional one hour at 120 C., warmed to 175 C. at 2 C./min and held at 175 C. for two hours. The clear orange cured sample was cooled slowly to room temperature and removed from the PTFE dish to give a uniform transparent, dark orange disc.

(18) Weight fractions of the various resins in the PAES polymer mixture, plane strain fracture toughness (K.sub.IC) of the cured epoxy resin composition are summarized in table 2.

(19) Plane Strain Fracture Toughness (KIC) Test Method:

(20) The cured dark orange disc was cut using a band saw to give small rectangles (40123 mm.sup.3) with carefully measured dimensions for measuring K.sub.IC according to ASTM-D5045. Each bar is then machine-notched in the middle and then a small crack started with a razor blade inside the notch. Stress is applied at each end of the bar and the energy needed to propagate the crack is calculated based on measurements of new crack formation. Usually five samples are prepared and measured to get an average K.sub.1C in units of MPa.Math.m.sup.1/2. Variability is typically around 5-10%.

(21) TABLE-US-00001 Weight fractions of resins in PAES polymer or PAES polymer mixture Viscosity* K.sub.IC** Examples #1 #2 #3 #4 #5 #6 #7 #8 (, Pa .Math. s) (MPa .Math. m.sup.1/2) C1 1.00 56 1.29 0.08 C2 0.75 0.25 41 1.14 0.05 C3 0.50 0.50 19.5 0.97 0.10 C4 1.00 7.6 0.83 0.06 5 0.75 0.25 26.2 1.22 0.08 6 0.50 0.50 12.8 1.21 0.10 C7 1.00 2.2 0.72 0.06 C8 0.50 0.50 10.9 1.02 0.09 C9 0.50 0.50 (19.5).sup.a 1.12 0.11 C10 0.50 0.50 9.2 0.95 0.06 C11 0.50 0.50 (9.2).sup.a 0.89 0.05 C12 0.50 0.50 11.8 1.02 0.07 *Under test conditions of 20 wt. % PAES polymer or PAES polymer mixture in TGAP at 60 C., as detailed above **Plane strain fracture toughness (K.sub.IC) of the cured epoxy resin composition consisting of TGAP/PAES polymer or PAES polymer mixture/DDS = 54.4/21.7/23.9 wt. %