PROCESS FOR RECLAIMING SCRAP OR UNUSED EPOXY RESIN PREPREG

Abstract

Method for recycling scrap that contains one or more heat resistant fibers and from 25 to 60 wt. %, based on the total weight of the scrap, of an at least partially uncured to fully uncured two component thermosetting resin mixture of (i) one or more thermosetting resins, and (ii) a solid hardener, the methods comprising shredding the scrap to an average size of from 3 to 50 mm, mixing the shredded scrap, preferably after preheating the scrap, to provide a fluid material charge and then compression molding the fluid material charge to make a cured composite material.

Claims

1. A method for reclaiming scrap containing from 25 to 60 wt. %, based on the total weight of the scrap, of an at least partially uncured to fully uncured two component thermosetting resin mixture of (i) one or more thermosetting resins, and (ii) a latent hardener and/or catalyst, and one or more heat resistant fibers, the method comprising shredding the scrap, then mixing the shredded scrap to provide a fluid material charge and then compression molding the fluid material charge to make a cured composite material.

2. The method as claimed in claim 1, wherein the method comprises the shredding and then preheating the scrap to from 40 to 100 C. and then batch mixing the preheated scrap to provide the fluid material charge.

3. The method as claimed in claim 1, wherein the (i) one or more thermosetting resins comprises epoxy resin, vinyl ester resin, or polyester.

4. The method as claimed in claim 1, wherein in the method, the scrap contains the one or more heat resistant fibers impregnated or infused with the one or more at least partially uncured to fully uncured two component thermosetting resin mixture, and the method comprises shredding the scrap material into pieces having an average size of from 3 to 50 mm, mixing the shredded scrap material to form a fluid charge by (a) extruding the shredded material at a temperature A which is at least 10 C. above the glass transition temperature (Tg, Dynamic DSC) of the (i) thermosetting resin in the uncured two component thermosetting resin mixture that has the highest Tg (Dynamic DSC) of the thermosetting resins in the scrap material (Temperature B), or by (b) preheating the shredded scrap material to at least 5 C. above the Temperature B, followed by batch mixing the shredded material at least the Temperature B; followed by compression molding the fluid charge to make a cured composite, further wherein, in (a) or (b), if needed, the mixing includes combining the shredded scrap material with a sufficient amount of one or more uncured two component thermosetting resin mixture which has a Tg of below Temperature B to provide a fluid material charge having a total of from 25 to 60 wt. %, based on the total weight of the scrap, of the uncured two component thermosetting resin mixture.

5. The method as claimed in claim 1, wherein the mixing includes combining the shredded scrap material with any of (i) a thermosetting resin having a Tg above 30 C., a liquid thermosetting resin, or mixtures thereof; (ii) virgin chopped fiber, for example, glass fiber and/or carbon fiber; one or more additives, such as catalysts, hardeners, tougheners or mold release agents, preferably, mold release agents; (iii) molding materials, such as random or bulk molding compounds, comprising virgin chopped fibers and thermosetting resins, wherein in (ii) or (iii), wherein the resulting shredded scrap material contains from 25 to 60 wt. % of total uncured thermosetting resin, based on the total weight of the resulting shredded scrap material.

6. The method as claimed in claim 1, further comprising shaping the fluid charge into a desired shape by using nip rolls, or a laminator, or by casting into different molds, prior to compression molding.

7. The method as claimed in claim 1, wherein the uncured two component thermosetting resin mixture comprises (i) one or more liquid epoxy resins.

8. The method as claimed in claim 1, wherein the uncured two component thermosetting resin mixture comprises (i) one or more epoxy resins that has a viscosity (oscillatory shear rate sweep from 0.1-100 rad/sec at 25% strain in a 25 mm parallel plate geometry, Rheometer,) of from 500 to 300,000 mPa.Math.s at room temperature.

9. The method as claimed in claim 1, wherein the one or more heat resistant fibers is chosen from carbon fiber, glass fiber, ceramic fiber, acrylonitrile fibers, aramid fibers, or their admixtures.

10. The method as claimed in claim 1, wherein the one or more latent hardener and/or catalyst, is a solid catalyst chosen from a urea containing catalyst, a urea resin containing catalyst, a dicyandiamide and an oxazolidine group containing catalyst.

Description

EXAMPLES

[0064] The following examples are used to illustrate the present invention without limiting it to those examples. Unless otherwise indicated, all temperatures are ambient temperatures and all pressures are 101 kPa (1 atmosphere).

[0065] The following materials and chemicals were used in the Examples that follow:

[0066] Epoxy Resin 1: A liquid epoxy resin of a digycidyl ether of bisphenol A, having an epoxy equivalent weight (EEW) of 184 to 191 g/eq;

[0067] Epoxy Resin 2: A liquid epoxy novolac resin 1, EEW 175-181 g/eq;

[0068] Epoxy Resin 3: A liquid epoxy resin of a diglycidyl ether of bisphenol A, EEW 176-182 [DER 383];

[0069] Epoxy Resin 4: A solid epoxy resin of a digycidyl ether of bisphenol A, EEW of 395 to 405 g/eq., Tg (DSC) 45 C.;

[0070] Hardener: Dicyandiamide (Technicure NanoDicy, Air Products & Chemicals, Inc., Allentown, Pa.) AHEW of 21 g/eq.;

[0071] Hardener 2: DETDA (Diethyltoluenediamine) with Cu(BF.sub.4).sub.2, DEH 650 (Olin Corporation, Clayton, Mo.);

[0072] Catalyst 1: Urea group containing catalyst, TBDMU (Toluenebis dimethyl urea) (Omicure U-410M, CVC Thermoset Specialties, Moorestown, N.J.);

[0073] Catalyst 2: Imidazole group containing catalyst (Curezol 2MZ-A, Shikoku Chemicals Corp., Tokyo, JP);

[0074] Catalyst 3: HYCAT 3100s Trivalent chromium (Ill) carboxylate complex containing <10 wt. % phenol and <10 wt. % benzyldimethylamine (1.79 wt. %), 1 methyl imidazole (1.79 wt. %) (Dimension Technology Chemical Systems, Inc., Fair Oaks, Calif.);

[0075] Mold Release Agent 1: Licowax-S montan fatty acid wax (Clariant, Pratteln, CH);

[0076] Mold Release Agent 2: Licolub WE4 montan fatty acid ester wax (Clariant);

[0077] Carbon fiber (12K fibers in a tow, A42-D012, DowAksa, Turkey);

[0078] UD: Unidirectional fiber prepreg of carbon fiber;

[0079] NCF: Non Crimp Fabric of carbon fiber (590 g/m.sup.2); and,

[0080] Braid: Braided fabric of carbon fiber (733 g/m.sup.2).

[0081] Test Methods:

[0082] Glass Transition Temperature (Tg) by Dynamic Differential Scanning Calorimetry (DSC):

[0083] Dynamic DSC, as defined above.

[0084] Initial Glass Transition Temperature (Initial Tg):

[0085] As defined above.

[0086] Cured Glass Transition Temperature (Cured Tg):

[0087] A 5 mm diameter disk was cut out of a cured molded material and the DSC of the molded material was determined from a single temperature sweep from 25 to 200 C. at a 10 C./min ramp rate, as defined above.

[0088] Initial Tool Coverage:

[0089] During compression molding, a charge of molding compound is placed on the tool (mold) and then pressure and temperature is applied for it to flow, fill the tool and cure. Initial tool coverage is the percentage area that the molding compound covers relative to the final molded part.

[0090] Tensile or Young's Modulus:

[0091] This property was measured according to ASTM standard D3039 (2014) on an Instron (Model #5967) tensile testing set up using a 647 hydraulic wedge grip with a grip set pressure of 20,000 kPa. The pull speed used was 5 mm/min and strain was recorded using Instron W-00129 video extensometer.

[0092] Tensile Strength:

[0093] This property was measured according to ASTM standard D3039 (2014) on an Instron (Model #5967, Instron Engineering Corp., an ITW Company, Norwood, Mass.) tensile testing set up using a 647 hydraulic wedge grip with a grip set pressure of 20,000 kPa. The pull speed used was 5 mm/min and strain was recorded using Instron W-00129 video extensometer.

Example 1: Flowability Vs. Particle Size

[0094] To demonstrate the effective range of shredded material particle size, the Scrap (A) listed in Table 1, below, was shredded to the indicated average particle size (see Table 2, below) using the indicated shredding device (see Table 2, below), followed by preheating the Scrap (A) and mixing it for 10 minutes with the indicated make-up materials (B) in a stainless steel (SS316L) batch sigma mixer (Sigma Blade, Jaygo Inc., Union, N.J.) having a 15 L capacity, and kept at 25 C. Each formulation had a target fiber content of 50 wt. %. In each Example, the scrap was preheated to 55 C. prior to mixing. In each Example, the weight ratio of Scrap (A) to Make-up material (B) was 83.3:16.7 wt. %.

[0095] Following mixing, the several pieces of the indicated materials were compression molded at 26,200 kPa (3800 psi) at a molding temperature of 150 C. for 3 minutes in an attempt to make a 30 cm30 cm (1212) plaque. The shredded Scrap (A) material size, the initial tool coverage, and the results of molding are indicated in Table 2, below.

TABLE-US-00001 TABLE 1 Materials EXAMPLE 1.1 1.2 1.3 1.4* 1.5* wt. % wt. % wt. % wt. % wt. % Scrap Formulation (A) Epoxy Resin 4 13.23 13.23 13.23 13.23 13.23 (Solid) Epoxy Resin 2 13.90 13.90 13.90 13.90 13.90 Epoxy Resin 1 7.45 7.45 7.45 7.45 7.45 Mold Release 0.86 0.86 0.86 0.86 0.86 Agent 1 Hardener 3.17 3.17 3.17 3.17 3.17 Catalyst 2 0.00 0.00 0.00 0.00 0.00 Catalyst 1 1.38 1.38 1.38 1.38 1.38 Carbon Fiber 60.00 60.00 60.00 60.00 60.00 Carbon Fiber UD UD UD NCF NCF Fabric Make-up Formulation (B) Epoxy Resin 4 0.00 0.00 0.00 0.00 0.00 (Solid) Epoxy Resin 2 0.00 0.00 0.00 0.00 0.00 Epoxy Resin 3 88.03 88.03 88.03 88.03 88.03 Mold Release 3.52 3.52 3.52 3.52 3.52 Agent 1 Hardener 5.81 5.81 5.81 5.81 5.81 Catalyst 2 2.64 2.64 2.64 2.64 2.64 Catalyst 1 0.00 0.00 0.00 0.00 0.00 Shredder Cross cut Reel slit Reel slit =Bi-cutter Reel slit paper cutter cutter shredder.sup.2 cutter shredder.sup.1 .sup.1Staples model SPL-TXC24A, Staples office stores; .sup.2SRS Systems, Inc., Cicero, NY; *Denotes Comparative Example.

TABLE-US-00002 TABLE 2 Mechanical Properties and Ease Of Moldability EXAMPLE 1.1 1.2 1.3 1.4* 1.5* Shredded material 7.5 mm 22 mm 22 mm 2.5 mm 63.5 mm size (L W) 11 mm 51 mm 76.2 mm 2.5 mm 63.5 mm Initial tool 25%-100% 50%-100% 100% 50% 75% coverage Molding Comment Formed into a Formed Formed The mixed Difficulty in rectangular into a into a mass was mixing. brick (101.6 mm rectangular rectangular very dry High torque 101.6 mm, brick brick and could consumed 203.2 mm (203.2 mm (304.8 mm not be during 203.2 mm, 203.2 mm, 304.8 mm) formed process 254 mm 254 mm into a 254 mm) 254 mm) brick Molding Result Good Part Good Part Good Part Incomplete Incomplete with no defect with no with no Non- Non- defect defect uniform uniform part part Cured Tg 142-150 C. 142-150 C. 142-150 C. 142-150 C. 142-150 C. Tensile Modulus 25.7 Gpa 23.6 Gpa 26.4 Gpa Not Not available available Tensile Strength 110 Mpa 93 MPa 114 MPa Not Not available available *Denotes Comparative Example.

[0096] As shown in Table 2, above, molded plaques of recycled scrap material were obtained when the materials were shredded to the desired size of the present invention, as in Examples 1.1, 1.2 and 1.3. When materials were shredded too small, as in Example 1.4 or too large, as in Example 1.5, molding failed.

Example 2: Scrap Resin Tg and Shredding in Molding

[0097] To demonstrate the influence of initial Tg of the scrap on the processability and the resulting molding properties, the Scrap (A) listed in Table 3, below, was shredded using an industrial shredder combo machine (model IS-20 combo shredder, Industrial Shredders Inc., Olmsted Falls, Ohio) to the average particle size indicated in Table 4, below, followed by preheating the Scrap (A) and mixing it for 10 minutes with the indicated make-up materials (B) in a stainless steel (SS316L) batch sigma mixer (Sigma Blade, Jaygo Inc., Union, N.J.) having a 15 L capacity, and kept at 25 C. Each formulation had a target fiber content of 50 wt. %. In each Example, the scrap was preheated to 55 C. prior to mixing. In each Example, the weight ratio of Scrap (A) to Make-up material (B) was 83.3:16.7 wt. %.

[0098] Following mixing, several pieces of each of the indicated materials were compression molded at 26,200 kPa (3800 psi) at a molding temperature of 150 C. for 3 minutes in an attempt to make a 30 cm30 cm (1212) plaque. The shredded Scrap (A) material size, the initial tool coverage, and the results of molding are indicated in Table 4, below.

TABLE-US-00003 TABLE 3 Materials EXAMPLE 2.1 2.2* 2.3 2.4* wt. % wt. % wt. % wt. % Scrap Formulation (A) Epoxy Resin 4 (Solid) 13.23 13.23 13.23 13.23 Epoxy Resin 2 13.90 13.90 13.90 13.90 Epoxy Resin 1 7.45 7.45 7.45 7.45 Mold Release Agent 1 0.86 0.86 0.86 0.86 Hardener 3.17 3.17 3.17 3.17 Catalyst 2 0.00 0.00 0.00 0.00 Catalyst 1 1.38 1.38 1.38 1.38 Carbon Fiber 60.00 60.00 60.00 60.00 Carbon Fiber Fabric UD NCF Braid NCF Scrap Initial Tg (Dynamic DSC) 18 C. 5 C. 58 C. 85 C. Make-up Formulation (B) Epoxy Resin 4 (Solid) 0.00 0.00 0.00 0.00 Epoxy Resin 2 0.00 0.00 0.00 0.00 Epoxy Resin 3 88.03 88.03 88.03 88.03 Mold Release Agent 1 3.52 3.52 3.52 3.52 Hardener 5.81 5.81 5.81 5.81 Catalyst 2 2.64 2.64 2.64 2.64 Catalyst 1 0.00 0.00 0.00 0.00 *Denotes Comparative Example.

TABLE-US-00004 TABLE 4 Mechanical Properties and Ease Of Moldability EXAMPLE 2.1 2.2* 2.3 2.4* Shredded material 7.5 mm n/a 7.5 mm 7.5 mm size (L W) 11 mm 11 mm 11 mm Initial tool 25%-100% n/a 25-100% 50% coverage Molding 30 cm 30 cm n/a 30 cm 30 cm Comment plaque 30 cm 30 cm plaque plaque Molding Result Good Part Not Good Part Good Part with no molded with no with no defect defect defect Cured Tg 142-150 C. n/a 142-150 C. 142-150 C. Tensile Modulus 25-30 Gpa n/a 25-30 Gpa 25-30 Gpa Tensile Strength 110 Mpa n/a 108 MPa 38 MPa *Denotes Comparative Example.

[0099] As shown in Table 4, above, molded plaques of recycled scrap material were obtained when the materials were shredded to the desired size of the present invention, as in Examples 2.1, 2.3 and 2.4. However, when the scrap epoxy resin was too soft as in Example 2.2, the shredding failed; it is still possible to shred the Scrap of Example 2.2 when that Scrap is refrigerated and shredded. In Example 2.4, the epoxy resin was too hard and generated a high mixing torque in the batch sigma mixer; further, the hard epoxy resin and the make-up resin could not be flowed together and mixed well and the resulting molded part had poor tensile strength.

Example 3: Scrap Resin and Virgin Fiber in Molding

[0100] To demonstrate the feasibility of incorporating virgin carbon fiber into the final mix, the Scrap (A) listed in Table 5, below, was shredded using a cross cut paper shredder machine to an average size of 7.511 mm. In Examples 3.1, 3.2 and 3.4, this was followed by preheating the Scrap (A) to 55 C. and mixing it for 10 minutes with the indicated make-up materials (B) and (C) in the weight ratio indicated in Table 5, below, in a stainless steel (SS316L) batch sigma mixer (Sigma Blade, Jaygo Inc., Union, N.J.) having a 15 L capacity, and kept at 25 C. In Example 3.4, the Scrap (A) and indicated make-up materials (B) and (C) were fed into a twin screw extruder set at a temperature of 100 C. Each formulation had a target fiber content of 50 wt. %.

[0101] Following mixing, several pieces of each of the indicated materials were compression molded at 26,200 kPa (3800 psi) at a molding temperature of 150 C. for 3 minutes in an attempt to make a 30 cm30 cm (1212) plaque. The shredded Scrap (A) material size, the initial tool coverage and the results of molding are indicated in Table 6, below.

TABLE-US-00005 TABLE 5 Materials EXAMPLE 3.1 3.2 3.3 3.4 wt. % wt. % wt. % wt. % Scrap Formulation (A) Epoxy Resin 4 (Solid) 13.23 27.70 13.23 13.23 Epoxy Resin 2 13.90 13.80 13.90 13.90 Epoxy Resin 1 7.45 4.60 7.45 7.45 Mold Release Agent 1 0.86 0.00 0.86 0.86 Hardener 3.17 2.50 3.17 3.17 Catalyst 2 0.00 0.00 0.00 0.00 Catalyst 1 1.38 1.40 1.38 1.38 Carbon Fiber 60.00 50.00 60.00 60.00 Carbon Fiber Fabric NCF UD NCF NCF Make-up Formulation (B) Epoxy Resin 4 (Solid) 0.00 21.50 0.00 0.00 Epoxy Resin 2 0.00 21.50 0.00 0.00 Epoxy Resin 3 88.03 0.00 88.03 88.03 Mold Release Agent 1 3.52 1.70 3.52 3.52 Hardener 5.81 3.60 5.81 5.81 Catalyst 2 2.64 0.00 2.64 2.64 Catalyst 1 0.00 1.70 0.00 0.00 Carbon Fiber (Virgin) 0.00 50.00 0 0 (C) Chopped Carbon fiber (2.54 cm) 0.00 0.00 100.00 100.00 Wt. Ratio (A):(B):(C) 83.3%, 50%, 50%, 50%, 30%, 50%, 30%, 16.7%, 0% 0% 20% 20%

TABLE-US-00006 TABLE 6 Mechanical Properties and Ease Of Moldability EXAMPLE 3.1 3.2 3.3 3.4 Initial tool 25-100% 25-100% 25-100% 25-100% coverage Molding 30 cm 30 30 cm 30 cm 30 cm Comment cm plaque 30 cm 30 cm 30 cm plaque plaque plaque Molding Result Good Part Good Part Good Part Good Part with no with no with no with no defect defect defect defect Cured Tg 142-150 C. 142-150 C. 142-150 C. 142-150 C. Tensile 25.7 Gpa 25.1 Gpa 23.9 Gpa 25-30 Gpa Modulus Tensile 110 Mpa 112 Mpa 94 MPa 80-100 MPa Strength

[0102] As shown in Table 6, above, molded plaques of recycled scrap material were obtained when the materials were shredded to the desired size of the present invention, as in all of Examples 3.1, 3.2, 3.3 and 3.4. Accordingly, when make-up fiber and some make up resin are added and the fiber content of the final product is within the range of the present invention, a good molded product results as long as materials can be flowed together and mixed well. An extruder can be used in place of a batch mixer, as shown in Example 3.4; however, the tensile strength of such recycled products is not preferred.

Example 4: Effect of Mixer Type

[0103] To demonstrate that different types of mixers yields comparable part performance, the Scrap (A) listed in Table 7, below, was shredded using a cross cut paper shredder (Staples model SPL-TXC24A) to the average particle size of 7.5 mm11 mm. In Example 4.1, this was followed by preheating the Scrap (A) to 55 C. and mixing it for 10 minutes with the indicated make-up materials (B) in a stainless steel (SS316L) batch sigma mixer (Sigma Blade, Jaygo Inc., Union, N.J.) having a 15 L capacity, and kept at 25 C. In Example 4.2, this was followed by preheating the Scrap (A) to 55 C. and mixing it for 10 minutes with the indicated make-up materials (B) in a stainless steel (SS316) batch Henschel mixer (FM-10US mixer, Henschel America, Inc., Green Bay, Wis.) having a 9 L capacity, and kept at 25 C. In Example 4.3, the Scrap (A) and indicated make-up materials (B) were fed into a twin screw extruder set at a temperature of 100 C. In each Example, the weight ratio of Scrap (A) to Make-up material (B) was 83.3:16.7 wt. %. Each formulation had a target fiber content of 50 wt. %.

[0104] Following mixing, the indicated materials were compression molded at 26,200 kPa (3800 psi) at a molding temperature of 150 C. for 3 minutes in an attempt to make a 30 cm30 cm (1212) plaque. The initial tool coverage and the results of molding are indicated in Table 8, below.

TABLE-US-00007 TABLE 7 Materials EXAMPLE 4.1 4.2 4.3 wt. % wt. % wt. % Scrap Formulation (A) Epoxy Resin 4 (Solid) 13.23 13.23 13.23 Epoxy Resin 2 13.90 13.90 13.90 Epoxy Resin 1 7.45 7.45 7.45 Mold Release Agent 1 0.86 0.86 0.86 Hardener 3.17 3.17 3.17 Catalyst 2 0.00 0.00 0.00 Catalyst 1 1.38 1.38 1.38 Carbon Fiber 60.00 60.00 60.00 Carbon Fiber Fabric UD UD NCF Make-up Formulation (B) Epoxy Resin 4 (Solid) 0.00 0.00 0.00 Epoxy Resin 2 0.00 0.00 0.00 Epoxy Resin 3 88.03 88.03 88.03 Mold Release Agent 1 3.52 3.52 3.52 Hardener 5.81 5.81 5.81 Catalyst 2 2.64 2.64 2.64 Catalyst 1 0.00 0.00 0.00 Carbon Fiber (Virgin) 0.00 0.00 0.00

TABLE-US-00008 TABLE 8 Mechanical Properties and Ease Of Moldability EXAMPLE 4.1 4.2 4.3 Initial tool coverage 25-100% 25-100% 25-100% Molding Comment 30 cm 30 cm 30 cm 30 cm 30 cm 30 cm plaque plaque plaque Molding Result Good Part with Good Part with Good Part with no defect no defect no defect Cured Tg 142-150 C. 142-150 C. 142-150 C. Tensile Modulus 25.7 Gpa 25.1 Gpa 23.5 Gpa Tensile Strength 110 Mpa 112 Mpa 93.5 Mpa

[0105] As shown in Table 8, above, both a Sigma and a Henschel batch mixer can be used to make a recycled part with good mechanical properties. An extruder may also be used.

Example 5: Effect of Make-Up Resin Chemistry

[0106] To demonstrate that different chemistry yields comparable part performance, the Scrap (A) listed in Table 9, below, was shredded to an average particle size of 15 mm22 mm using a cross cut paper shredder (Staples model SPL-TXC24A), followed by preheating the Scrap (A) and mixing it for 10 minutes with the indicated make-up materials (B) in a stainless steel (SS316L) batch sigma mixer (Sigma Blade, Jaygo Inc., Union, N.J.) having a 15 L capacity, and kept at 40 C. Each formulation had a target fiber content of 50 wt. %. In each Example, the scrap was preheated to 55 C. prior to mixing. In each Example, the weight ratio of Scrap (A) to Make-up material (B) was 83.3:16.7 wt. %.

[0107] Following mixing, the indicated materials were compression molded at 26,200 kPa (3800 psi) at a molding temperature of 150 C. for 3 minutes in an attempt to make a 30 cm30 cm (1212) plaque. The initial tool coverage, and the results of molding are indicated in Table 10, below.

TABLE-US-00009 TABLE 9 Materials EXAMPLE 5.1 5.2 5.3 5.4 5.5* wt. % wt. % wt. % wt. % wt. % Scrap Formulation (A) Epoxy Resin 4 (Solid) 13.23 13.23 13.23 13.23 13.23 Epoxy Resin 2 13.90 13.90 13.90 13.90 13.90 Epoxy Resin 1 7.45 7.45 7.45 7.45 7.45 Mold Release Agent 1 0.86 0.86 0.86 0.86 0.86 Hardener 3.17 3.17 3.17 3.17 3.17 Catalyst 2 0.00 0.00 0.00 0.00 0.00 Catalyst 1 1.38 1.38 1.38 1.38 1.38 Carbon Fiber 60.00 60.00 60.00 60.00 60.00 Carbon Fiber Fabric NCF NCF NCF NCF NCF Make-up Formulation (B) Epoxy Resin 4 (Solid) 0.00 0.00 0.00 13.23 42.90 Epoxy Resin 2 0.00 25.20 0.00 13.90 42.90 Epoxy Resin 3 88.03 58.80 76.00 7.45 0.00 Mold Release Agent 1 3.52 5.90 3.00 3.00 3.40 Hardener 5.81 6.70 0.00 3.17 7.30 Catalyst 2 2.64 0.00 0.00 0.00 0.00 Catalyst 1 0.00 3.40 0.00 1.38 3.40 Hardener 2 0.00 0.00 19.00 0.00 0.00 Catalyst 3 0.00 0.00 2.00 0.00 0.00 Make-up Resin Tg During Mixing 10.0 5.0 13.0 12.0 26.0 ( C.) Make-up Resin Viscosity.sup.1 3.00 4.00 1.50 5.50 40.00 (Pa .Math. s @ 40 C.) *Denotes Comparative Example; .sup.1Oscillatory shear rate sweep from 0.1-100 rad/sec at 25% strain in a 25 mm parallel plate geometry (Rheometer).

TABLE-US-00010 TABLE 2 Mechanical Properties and Ease Of Moldability EXAMPLE 5.1 5.2 5.3 5.4 5.5* Initial tool 50% 50% 50% 50% 50% coverage Molding Formed into a Formed into a Formed into a Formed into a The mixed mass Comment rectangular rectangular rectangular rectangular was non-uniform brick brick brick brick with resin rich regions Molding Good Part Good Part Good Part Good Part Incomplete Result with no with no with no with no Non-uniform defect defect defect defect part Cured Tg 142-150 C. 146-155 C. 148-160 C. 146-152 C. 130-152 C. *Denotes Comparative Example.

[0108] As shown in Table 10, above, good molded plaques of recycled scrap material were obtained when the make-up resin (B), including any hardener and catalyst had a Tg of less than about 20 C., as in Examples 5.1, 5.2, 5.3 and 5.4. When the make-up resin (B) was too hard, complete mixing was not possible and, as in Example 5.5, molding failed.