METHOD FOR THE RUBBER MODIFICATION OF THERMOSETTING RESINS

Abstract

The present invention relates to a process for producing thermoset moldings, to the thermoset moldings themselves, to the use of the thermoset moldings as components and to the use of a thermoplastic polymer having a porosity in the range from 10% to 90% for increasing the toughness of a thermoset.

Claims

1.-15. (canceled)

16. A process for producing a thermoset molding, comprising the steps of a) providing a thermosettably crosslinkable resin system in a mold, b) crosslinking the thermosettably crosslinkable resin system provided in step a) in the mold in the presence of a thermoplastic polymer having a porosity of 10% to 90% to obtain the thermoset molding, c) removing the thermoset molding from the mold.

17. The process according to claim 16, wherein the thermosettably crosslinkable resin system provided in process step a) is selected from the group consisting of thermosettably crosslinkable epoxy resin systems, thermosettably crosslinkable urea-formaldehyde resin systems, thermosettably crosslinkable melamine-formaldehyde resin systems, thermosettably crosslinkable melamine-phenol-formaldehyde resin systems, thermosettably crosslinkable phenol-formaldehyde resin systems and thermosettably crosslinkable bismaleimide resin systems.

18. The process according to claim 16, wherein the thermoplastic polymer is selected from the group consisting of polyarylene ethers, polyphenylene ethers, polyetherimides and mixtures of polyarylene ethers, polyphenylene ethers and polyetherimides.

19. The process according to claim 16, wherein the thermoplastic polymer is at least one polyarylene ether (P) formed from units of the general formula (I) ##STR00005## with the following definitions: t, q: independently 0, 1, 2 or 3, Q, T, Y: each independently a chemical bond or group selected from O, S, SO.sub.2, SO, CO, NN, CR.sup.aR.sup.b where R.sup.a and R.sup.b are each independently a hydrogen atom 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, where at least one of Q, T and Y is different than O, and at least one of Q, T and Y is SO.sub.2 and Ar, Ar.sup.1: each independently an arylene group having from 6 to 18 carbon atoms.

20. The process according to claim 19, wherein the polyarylene ether (P) has end groups, where at least 60% of the end groups are phenol end groups, based on the total number of end groups in the polyarylene ether (P).

21. The process according to claim 16, wherein the thermoplastic polymer is selected from the group consisting of polyether sulfones (PESU), polysulfones (PSU) and polyphenyl sulfones (PPSU).

22. The process according to claim 16, wherein the thermosettably crosslinkable resin system provided in process step a) is an epoxy resin system comprising the following components: (A) at least one epoxy compound (E) having at least one epoxy group per molecule, and (B) at least one hardener (H).

23. The process according to claim 22, wherein the epoxy compound (E) has at least two epoxy groups per molecule.

24. The process according to claim 22, wherein the epoxy compound (E) is a bisglycidyl ether based on bisphenols of the general formula (II): ##STR00006## where: R.sup.1 to R.sup.4 and R.sup.7 to R.sup.10 are each independently H, C.sub.1-C.sub.6-alkyl, aryl, halogen or C.sub.2-C.sub.10-alkenyl, where R.sup.1 to R.sup.4 and R.sup.7 to R.sup.10 may also be part of a ring system; X is CR.sup.5R.sup.6 or SO.sub.2; if X is CR.sup.5R.sup.6, R.sup.5 and R.sup.6 are each independently H, halogen, C.sub.1-C.sub.6-alkyl, C.sub.2-C.sub.10-alkenyl or aryl or R.sup.5 and R.sup.6 may also be part of a ring system.

25. The process according to claim 22, wherein the epoxy compound (E) is a bisglycidyl ether based on bisphenols, in which the bisphenols are selected from the group of bisphenol A (CAS: 80-05-7), bisphenol AF (CAS: 1478-61-1), bisphenol AP (CAS: 1571-75-1), bisphenol B (CAS: 77-40-7), bisphenol BP (CAS: 1844-01-5), bisphenol C (CAS: 79-97-0), bisphenol C (CAS: 14868-03-2), bisphenol E (CAS: 2081-08-5), bisphenol F (CAS: 620-92-8), bisphenol FL (CAS: 3236-71-3), bisphenol G (CAS: 127-54-8), bisphenol M (CAS: 13595-25-0), bisphenol P (CAS: 2167-51-3), bisphenol PH (CAS: 24038-68-4), bisphenol S (CAS: 80-09-1), bisphenol TMC (CAS: 129188-99-4) and bisphenol Z (CAS: 843-55-0).

26. The process according to claim 22, wherein the epoxy compound (E) is selected from the group of tetraglycidylmethylenedianiline (TGMDA), epoxy novolaks and cycloaliphatic epoxy compounds.

27. The process according to claim 22, wherein the hardener (H) is selected from the group consisting of 1,3-diaminobenzene, 2,6-bis(aminomethyl)-piperidine, diethylenetriamine, triethylenetetramine, 4,4-diaminodiphenyl sulfone, phthalic anhydride and hexahydrophthalic anhydride.

28. The process according to claim 16, wherein in process step a) a reinforcing material is additionally provided in the mold before the thermoset resin system is provided.

29. The process according to claim 28, wherein the thermoplastic polymer is applied to the reinforcing material.

30. A method for increasing the toughness of a thermoset molding which comprises utilizing a thermoplastic polymer having a porosity of 10% to 90%.

Description

EXAMPLES

[0132] The thermoplastic polymer used was a polyether sulfone having a viscosity number of 56 ml/g. The viscosity number was determined in 1 percent solution in 1/1 phenol/o-dichlorobenzene. The polyether sulfone had at least 60% OH end groups, based on the total number of end groups. The polyether sulfone is available under the Ultrason E 2020 P SR trade name from BASF SE.

[0133] The epoxy compound (E) used was a bisphenol A diglycidyl ether having a mean molecular weight of 395 g/mol.

[0134] The hardener (H) used was hexahydrophthalic anhydride.

[0135] The hardening accelerator (HA) used was 2-ethyl-4-methylimidazole.

Preparation of a Thermoplastic Polymer without Pores (Noninventive); F I Hereinafter

[0136] In a DSM miniextruder (15 cc type) equipped with a film die, 15 g of the above-described polyether sulfone were melted at a temperature of 340 C. For this purpose, the polyether sulfone was circulated through an internal return flow channel for five minutes. Subsequently, the polyether sulfone was discharged through the film die having a gap width of 150 m. The foil (F I) obtained was transparent, but highly discolored, very brittle and friable. On dissolution of 1 g of the foil in 20 mL of N-methylpyrrolidone (NMP) at 25 C. for a period of eight hours, an insoluble fraction remained. The density of the foil was determined by gravimetric means and was 1.37 g/cm.sup.3.

Preparation of a Thermoplastic Polymer Having a Porosity in the Range from 10% to 90% (Inventive); F II Hereinafter

[0137] A solution of 30 g of the above-described polyether sulfone, 5 g of K30 polyvinylpyrrolidone (hydrophilic polymer) in 65 g of NMP was formed at room temperature (25 C.) with the aid of a coating bar having a width of 10 cm into a solution film of thickness 300 m on a glass plate. Subsequently, the glass plate was transferred into a water bath (coagulant), which gave a white film which became detached from the glass plate after three minutes. The film (F II) thus obtained was subsequently washed with warm water at 60 C. for four hours and then dried at 100 C. under reduced pressure for twelve hours. After drying, the thermoplastic polymer having a porosity of 10% to 90% was obtained. The presence of pores is demonstrated by the lack of transparency and the distinct reduction in density. The density of the film (F II) was determined by gravimetric means and was 0.56 g/cm.sup.3. The porosity of the film is 58.8%.

Preparation of a Thermoplastic Polymer Having a Porosity in the Range from 10% to 90% (Inventive); F Ill Hereinafter

[0138] A solution of 30 g of the above-described polyether sulfone, 5 g of polyethyleneoxide (Mn=6000 g/mol; hydrophilic polymer) in 65 g of NMP was formed at room temperature (25 C.) with the aid of a coating bar having a width of 10 cm into a solution film of thickness 300 m on a glass plate. Subsequently, the glass plate was transferred into a water bath (coagulant), which gave a white film which became detached from the glass plate after 1.5 minutes. The film (F III) thus obtained was subsequently washed with warm water at 60 C. for four hours and then dried at 100 C. under reduced pressure for twelve hours. After drying, the thermoplastic polymer having a porosity of 10% to 90% was obtained. The presence of pores is demonstrated by the lack of transparency and the distinct reduction in density. The density of the film (F III) was determined by gravimetric means and was 0.75 g/cm.sup.3. The porosity of the film is 45.3%.

Preparation of a Thermoplastic Polymer Having a Porosity in the Range from 10% to 90% (Inventive); F IV Hereinafter

[0139] A solution of 40 g of the above-described polyether sulfone in 60 g of NMP was formed at room temperature (25 C.) with the aid of a coating bar having a width of 10 cm into a solution film of thickness 300 m on a glass plate. Subsequently, the glass plate was transferred into a water bath (coagulant), which gave a white film which became detached from the glass plate after four minutes. The film (F IV) thus obtained was subsequently extracted with warm water at 85 C. for ten hours and then dried at 100 C. under reduced pressure for twelve hours. After drying, the thermoplastic polymer having a porosity of 10% to 90% was obtained. The presence of pores is demonstrated by the lack of transparency and the distinct reduction in density. The density of the film (F IV) was determined by gravimetric means and was 0.87 g/cm.sup.3. The porosity of the film is 36.5%.

Preparation of a Thermoplastic Polymer Having a Porosity in the Range from 10% to 90% (Inventive); F V Hereinafter

[0140] A solution of 15 g of the above-described polyether sulfone, 5 g of K30 polyvinylpyrrolidone (hydrophilic polymer) in 80 g of NMP was formed at room temperature (25 C.) with the aid of a coating bar having a width of 10 cm into a solution film of thickness 150 m on a glass plate. Subsequently, the glass plate was transferred into a water bath (coagulant), which gave a white film which became detached from the glass plate after two minutes. The film (F V) thus obtained was subsequently extracted with warm water at 85 C. for ten hours and then dried at 100 C. under reduced pressure for twelve hours. After drying, the thermoplastic polymer having a porosity of 10% to 90% was obtained. The presence of pores is demonstrated by the lack of transparency and the distinct reduction in density. The density of the film (F V) was determined by gravimetric means and was 0.28 g/cm.sup.3. The porosity of the film is 79.6%.

Preparation of a Thermoplastic Polymer Having a Porosity Greater than 90% (Comparative); F VI Hereinafter

[0141] A solution of 7.5 g of the above-described polyether sulfone, 5 g of K30 polyvinylpyrrolidone (hydrophilic polymer) in 87.5 g of NMP was formed at room temperature (25 C.) with the aid of a coating bar having a width of 10 cm into a solution film of thickness 50 m on a glass plate. Subsequently, the glass plate was transferred into a water bath (coagulant), which gave a white film which became detached from the glass plate after 1.5 minutes. The film (F VI) thus obtained was subsequently extracted with warm water at 85 C. for ten hours and then dried at 100 C. under reduced pressure for twelve hours. After drying, the thermoplastic polymer having a porosity greater than 90% was obtained as a brittle white film (F VI). The presence of pores is demonstrated by the lack of transparency and the distinct reduction in density. The density of the film (F VI) was determined by gravimetric means and was 0.11 g/cm.sup.3. The porosity of the film is 92.0%.

[0142] Processing of the film (F VI) was not possible due to the high porosity,

Preparation of a Thermoplastic Polymer Having a Porosity Smaller than 10% (Comparative); F VII Hereinafter

[0143] A solution of 55 g of the above-described polyether sulfone in 45 g of NMP was formed at room temperature (25 C.) with the aid of a coating bar having a width of 10 cm into a solution film of thickness 300 m on a glass plate. Subsequently, the glass plate was transferred into a water bath (coagulant), which gave a white film which became detached from the glass plate after 60 minutes. The film (F VII) thus obtained was subsequently extracted with warm water at 85 C. for ten hours. Subsequently, the film was further dried at 60 C. for two hours, then at 100 C. for another 2 hours and at 140 C. for six hours each under reduced pressure. After drying, the thermoplastic polymer having a porosity smaller than 10% was obtained. The presence of pores is demonstrated by the at least partial lack of transparency and the slight reduction in density. The density of the film (F VII) was determined by gravimetric means and was 1.28 g/cm.sup.3. The porosity of the film is 6.6%.

[0144] The presence of transparent areas in the thermoplastic polymer can be attributed to a residual amount of NMP of approximately 2 wt-%, based on the total weight of the thermoplastic polymer. The film could not be used due to the high content of NMP.

Preparation of a Thermoplastic Polymer Having a Porosity in the Range from 10% to 90% (Inventive); Fiber I Hereinafter

[0145] A solution of 300 g of the above-described polyether sulfone, 50 g of K30 polyvinylpyrrolidone (hydrophilic polymer) in 650 g of NMP was formed at room temperature (25 C.) and extruded into a precipitation bath containing water with the aid of an annular gap. The hollow fiber (Fiber I) thus obtained was subsequently washed with warm water at 60 C. for eight hours and then dried at 100 C. under reduced pressure for twelve hours. After drying, the thermoplastic polymer was obtained as a white hollow fiber (Fiber I) having an external diameter of 45025 m and an internal diameter of 30015 m as well as a porosity of 10% to 90%. The presence of pores is demonstrated by the lack of transparency and the distinct reduction in density. The density of the hollow fiber (Fiber I) was determined by gravimetric means and was 0.66 g/cm.sup.3. The porosity of the film is 51.8%.

Production of the Thermoset Moldings

[0146] For production of the thermoset moldings, in each case 120 g of the epoxy compound (E) and 100 g of the hardener (H) were mixed at 80 C. until the distribution was homogeneous. Thereafter, at 80 C., the amounts of the foil (F I), the film (F II to F V) or the hollow fiber (Fiber I) specified in table 1 below in each case were added. Subsequently, the mixture was stirred until the foil (F I), the film (F II to F V) or the hollow fiber (Fiber I) had dissolved. The time taken for dissolution was determined. This was followed by cooling down to 40 C. and subsequent addition of 2.4 g of the hardening accelerator (HA) at 40 C. while stirring vigorously. Subsequently, the mixture thus obtained was degassed under reduced pressure for 10 minutes in order to remove bubbles. Then the mixture was hardened at a temperature of 80 C. for 24 hours and subsequently post-hardened at 200 C. for a period of 30 minutes.

[0147] The thermoset moldings thus obtained were used to elaborate samples of dimensions 80*10*2 mm. After introduction of a notch (depth 2 mm, radius 2.5 mm), the notched impact strength was tested in accordance with ISO 180. The color of the sample was assessed visually (+ very good; +/o good; o satisfactory; o/ adequate; inadequate; unsatisfactory).

[0148] The results are listed in the table below.

TABLE-US-00001 TABLE 1 Molding compound C1 C2 C3 4 5 6 7 8 9 10 11 A* 90 85 80 90 85 20 85 85 85 85 80 F I 10 15 20 F II 10 15 20 F III 15 F IV 15 FV 15 Fiber I 15 20 Mixing time [h] 5.2 6.5 7 2.5 3.2 4 4 4.25 3 3.5 4.25 Transparency no no no no no no no no no no No Intrinsic color o/ + +/o o +/o +/o +/o +/o +/o a.sub.k [kJ/m.sup.2] 0.23 0.26 0.27 0.87 0.92 1.06 0.47 0.44 0.47 0.46 0.50 A* indicates the proportion of the epoxy resin system consisting of epoxy compound (E), hardener (H) and hardening accelerator (HA) in percent by weight. The proportions of the foil (F I), the film (F II to F V) or the hollow fiber (Fiber I) are likewise stated in percent by weight. C1, C2 and C3 are comparative examples in which the nonporous foil (F I) is used. Examples 4, 5 and 6 are inventive examples in which the porous film (F II) is used. Examples 7 to 9 are further inventive examples in which the porous film (F III) is used in example 7, the porous film (F IV) is used in example 8 and the porous film (F V) is used in example 9. The examples 10 and 11 are further inventive examples in which the hollow fiber (Fiber I) is used.

[0149] The present examples show that the use of thermoplastic polymers having a porosity in the range from 10% to 90% enables much quicker dissolution of the thermoplastic polymer in the epoxy resin system. Furthermore, thermoset moldings having a distinct improvement in intrinsic color and a distinct improvement in notched impact strength are obtained if the crosslinking of the thermosettably crosslinkable resin system is conducted in the presence of a thermoplastic polymer having a porosity in the range from 10% to 90%.