USE OF VULCANIZABLE COMPOSITIONS AND VULCANIZATES IN CONTACT WITH COOLANT, COMPRISING SILANE-COATED WOLLASTONITE

Abstract

The present invention relates to a process for producing a vulcanizate which is in contact with coolant and to the use of a vulcanizable composition comprising rubber, silane-coated wollastonite and peroxide compound for production of vulcanizates in contact with coolant.

The invention further relates to a process for production and to the use of a vulcanizate produced from a vulcanizable composition comprising rubber, silane-coated wollastonite and peroxide compound as a component part, preferably as a seal or as a hose, in contact with coolant.

Claims

1. A process for producing a vulcanizate for use in contact with coolant, the process comprising vulcanizing a vulcanizable composition comprising: (a) at least one rubber, (b) at least one silane-coated wollastonite, and (c) at least one peroxide compound.

2. The process according to claim 1, wherein the at least one rubber (a) is at least one hydrogenated nitrile rubber comprising a fully or partly hydrogenated co- or terpolymer based on at least one conjugated diene and at least one ,-unsaturated nitrile monomer and optionally further copolymerizable monomers.

3. The process according to claim 1, wherein the at least one rubber (a) is at least one hydrogenated nitrile rubber having a Mooney viscosity (ML 1+4@100 C.) of 10 to 120 MU, where the Mooney viscosity is determined according to ASTM Standard D1646.

4. The process according to claim 1, wherein the composition comprises 35 to 150 parts by weight of the at least one silane-coated wollastonite (b), based on 100 parts by weight of the rubbers (a).

5. The process according to claim 1, wherein the at least one peroxide compound (c) is an organic peroxide.

6. The process according to claim 1, at least one filler which is a carbon black or a mineral filler.

7. The process according to claim 1, further comprising at least one ageing stabilizer selected from the group consisting of diphenylamine, mercaptobenzimidazole, substituted phenols and mixtures thereof.

8. The process according to claim 1, wherein the composition comprises: (a) 100 parts by weight of the at least one rubber, (b) 35 to 150 parts by weight of at least one silane-coated wollastonite (c) 1 to 20 parts by weight of the at least one peroxide compound, and (d) 0 to 100 parts by weight, of one or more customary rubber additives.

9. The process according to claim 1, wherein the vulcanizable composition comprises; (a) 100 parts by weight of at least one of hydrogenated nitrile rubber and EPDM, (b) 50 to 100 parts by weight of at least one vinylsilane-coated wollastonite, (c) 2 to 10 parts by weight, of at least one organic peroxide, and (d) 1 to 80 parts by weight, of one or more customary rubber additives, based on 100 parts by weight of the rubbers (a), where the composition has a content of zinc ions that is less than 1.5 parts by weight based on 100 parts by weight of the rubbers (a).

10. A vulcanizable composition comprising; (a) 100 parts by weight of hydrogenated nitrile rubber, (b) 50 to 85 parts by weight of an epoxysilane-, methacryloylsilane- or vinylsilane-coated wollastonite or mixtures thereof, and (c) 2 to 10 parts by weight of at least one peroxide compound, and the composition has a zinc ion content of less than 1.5 parts by weight based on 100 parts by weight of the rubbers (a).

11. A component part comprising a vulcanizate usable in contact with a coolant, the vulcanizate comprising a vulcanizable composition comprising: (a) at least one rubber, (b) at least one silane-coated wollastonite, and (c) at least one peroxide compound.

12. A process for producing a component in contact with coolant, the process comprising vulcanizing the vulcanizable composition as defined in claim 1 10 to produce a vulcanized component, and contacting the component with coolant.

13. The process according to claim 12, wherein the component is a hose, a heating hose, a cooling hose, a seal, or a cooling seal.

14. The process according to claim 12, wherein the coolant comprises water, a freezing point depressant, and a corrosion inhibitor.

15. A cooling unit comprising: (i) at least one component according to claim 11, and (ii) coolant, wherein the at least one vulcanizate is in contact with the coolant ii).

16. The process according to claim 14, wherein the freezing point depressant is ethylene glycol or propylene glycol, and the corrosion inhibitor Is sodium ethylhexanoate.

17. The process according to claim 1, wherein the composition comprises: 100 parts by weight of at least one fully or partly hydrogenated nitrile rubber comprising a fully or partly hydrogenated co- or terpolymer based on at least one conjugated diene and at least one ,-unsaturated nitrile monomer, and having a Mooney viscosity of 15 to 100 MU (ML1+4)@100 C.; 50 to 100 parts by weight of at least one silane-coated wollastonite selected from the group consisting of epoxysilane-coated wollastonite, methacryloylsilane-coated wollastonite, and vinylsilane-coated wollastonite; 2 to 10 parts by weight, of at least one organic peroxide selected from the group consisting of dicumyl peroxide, t-butyl cumyl peroxide, bis(t-butylperoxysopropyl)benzene, di-t-butyl peroxide, 2,5-dimethylhexane 2,5-dihydroperoxide, 2,5-dimethythex-3-yne 2,5-dihydroperoxide, dibenzoyl peroxide, bis(2,4-dichlrobenzoyl) peroxide, t-butyl perbenzoate, butyl 4,4-di(t-butylperoxy)valerate and 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; and 1 to 80 parts by weight, of one or more rubber additives selected from the group consisting of: filers selected from the group consisting of carbon black, silica, magnesium oxide, aluminium oxide, filler-activators based on an organic silane, ageing stabilizers selected from the group consisting of oligomerized 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), styrenized diphenylamine (DDA), octylated diphenylamine (OCD), cumylated diphenylamine (CDPA), zinc salt of 4- and 5-methylmercaptobenzimidazole (Vulkanox ZMB2), and zinc salt of 4- and 5-methylmercaptobenzimidazole, mould release agents, and processing aids, based on 100 parts by weight of the rubbers (a), and the composition is free of zinc ions.

Description

EXAMPLES

Production, Vulcanization and Characterization of the Compositions

[0153] Examples 7* and 8* which follow are non-inventive comparative examples, and Examples 1 to 6 and 9 are inventive examples. The comparative examples are identified in the tables which follow by an * after the example number.

[0154] The primary mixing unit used was an internal mixer of the GK 1.5 E type (manufacturer: HF Mixing Group). The speed was 40 min.sup.1, the cooling water inlet temperature 40 C.

[0155] This involved masticating the initial charge of the rubber (a) for 1 minute, then adding all further components apart from the vulcanization chemicals (peroxide compound and coagent). 3 minutes after commencement of mixing, the plunger was pulled out and brushed. After a mixing time of 250 seconds, the mixture was discharged.

[0156] The peroxide compound and the coagent were mixed in in a second step at 30 C. on a roll (manufacturer: Trster, roll diameter 20 cm). The friction was 1:1.11.

[0157] The speed of the roll was controlled here such that stable skins were obtained.

[0158] Subsequently, vulcanization of these skins was undertaken in slab presses at 180 C. for 15 min.

Components Used:

[0159]

TABLE-US-00001 Therban hydrogenated nitrile rubber, ACN content: 39% by 3907 weight, Mooney viscosity ML 1 + 4 @100 C.: 70 MU, residual double bond content: max. 0.9%. This rubber is commercially available from ARLANXEO Deutschland GmbH. Therban hydrogenated nitrile rubber, ACN content: 34% by 3407 weight, Mooney viscosity ML 1 + 4 @100 C.: 70 MU, residual double bond content: max. 0.9%, available from ARLANXEO Deutschland GmbH. Therban hydrogenated acrylate-comprising nitrile rubber, CAN LT 1707 VP content: 17% by weight, Mooney viscosity ML 1 + 4 @100 C.: 74 MU, residual double bond content: max. 0.9%, available from ARLANXEO Deutschland GmbH. Tremin epoxysilane-coated wollastonite, available from 283-600 EST Quarzwerke Tremin methacryloylsilane-coated wollastonite, available from 283-600 MST Quarzwerke Tremin vinylsilane-coated wollastonite, available from 283-600 VST Quarzwerke N550 Corax N 550 carbon black; available from Orion Engineered Carbon N774 Corax N 774 carbon black; available from Orion Engineered Carbon N990 Luvomaxx MT N-990 carbon black; available from Lehmann and Voss Luvomaxx 4,4-bis(1,1-dimethylbenzyl)diphenylamine, available CDPA from Lehmann and Voss Vulkanox 4- and 5-methyl-2-mercaptobenzimidazole; available MB2 from Lanxess Deutschland GmbH Vulkanox zinc salt of 4- and 5-methyl-2-mercaptobenzothiazole; ZMB2/C5 available from LANXESS Deutschland GmbH Maglite DE magnesium oxide, available from CP Hall. Active zinc zinc oxide (ZnO), commercially available from oxide LANXESS Deutschland GmbH TAIC 70% KETTLITZ-TAIC 70; coagent; available from Kettlitz- Chemie GmbH & Co. KG TOTM Uniplex 546; available from Rheinchemie Rheinau GmbH Rhenofit 70% trimethylolpropane trimethacrylate on 30% silica; TRIM/S coagent; available from Rhein Chemie Rheinau GmbH Perkadox di(tert-butylperoxyisopropyl)benzene 40% supported on 14-40 silica, available from Akzo Nobel Polymer Chemicals BV G13/water G13 coolant additive available from Volkswagen; for the mixture storage tests, 50 parts by volume of deionized water and 50 parts by volume of G13 coolant additive were mixed G64/water Glysantin G64 coolant additive based on ethylene mixture glycol available from BASF; for the storage tests 50 parts by volume of deionized water and 50 parts by volume of Glysantin G64 coolant additive were mixed 2-Ethyl- available from Sigma Aldrich hexanoic acid Ethylene available from Sigma Aldrich glycol

[0160] The amounts in part by weight stated in the examples are based on 100 parts by weight of the rubber (a).

[0161] The MDR (moving die rheometer) vulcanization profile and analytical data associated therewith were measured in a Monsanto MDR 2000 rheometer in accordance with ASTM D5289-95.

[0162] The tensile tests for determining the strain as a function of deformation were carried out in accordance with DIN 53504 or ASTM D412-80.

[0163] The Shore A hardness was measured in accordance with ASTM-D2240-81.

[0164] The hot air ageing was conducted in accordance with DIN 53508/2000. The method 4.1.1 Storage in a heating cabinet with positive ventilation was applied.

[0165] The storage tests in the G13/water mixture were effected in pressure vessels with a ratio of liquid to specimen of 150:1.

TABLE-US-00002 TABLE 1 Composition of the vulcanizable compositions Examples 1 2 3 4 5 6 7* 8* 9 [parts by weight] Therban 3907 100 100 100 100 100 100 100 Therban 3407 100 100 Tremin 283-600 EST 65 65 65 65 65 Tremin 283-600 MST 65 Tremin 283-600 VST 65 N550 50 N774 14 14 14 15 15 15 15 15 N990 65 Luvomaxx CDPA 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.1 1.5 Vulkanox MB2 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Vulkanox ZMB2 0.4 0.4 Maglite DE 3 3 3 3 3 3 3 Active zinc oxide 3 TAIC 70% 1.5 TOTM 5 5 Rhenofit TRIM/S 1.5 1.5 1.5 1.5 1.5 1.5 1.5 3 Perkadox 14-40 8 8 8 7.5 7.5 7.5 7.5 8 7.5

[0166] The vulcanizable composition of Example 7* serves as a comparative experiment for Examples 1 to 6, since it does not contain any silane-coated wollastonite (Tremin). The amount of 65 parts by weight of wollastonite based on 100 parts by weight of HNBR in Examples 1 to 6 was compensated for by the filler N990 in Example 7*. The vulcanizable composition of Example 8* serves as a comparative experiment for Example 9, since it does not contain any silane-coated wollastonite (Tremin). The amount of 65 parts by weight of wollastonite in Example 9 was compensated for in Example 8* by 50 parts by weight of the filler N550 in order to attain similar tensile strength values. Significantly less N550 than Tremin is required to obtain similar hardness and tensile strength.

[0167] Vulcanization was measured in a Monsanto MDR 2000 rheometer at a test temperature of 180 C. over a test duration of 15 min.

TABLE-US-00003 TABLE 2 Vulcanization characteristics of the vulcanizable compositions MDR at 180 C. 1 2 3 4 5 6 7* 8* 9 S min dNm 1.37 1.36 1.38 1.43 1.47 1.46 1.85 2.21 1.38 S max dNm 24.73 24.77 25.34 23.75 23.35 22.76 27.57 30.04 20.49 Delta S dNm 23.36 23.41 23.96 22.32 21.88 21.3 25.72 27.83 19.11 TS 1 s 31 31 31 33 33.6 33.6 29.4 28 37 TS 2 s 37 37 37 39.6 40.2 40.8 36 34 46 t 50 s 94 94 94 98.49 95.8 97.03 95.7 113 107 t 90 s 268 266 267 294 271 271 270.54 324 298 t 95 s 346 342 344 387 350 348 349.92 418 387 S min is the minimum torque of the crosslinking isotherm S max is the maximum torque of the crosslinking isotherm Delta S difference of Smax and Smin t 50: time at which 50% of the final conversion has been attained t 90: time at which 90% of the final conversion has been attained t 95: time at which 95% of the final conversion has been attained

[0168] The series of experiments shows that the compositions produced in accordance with the invention (1 to 6) have vulcanization characteristics comparable to the comparative example (7*). The inventive rubber mixture (9) likewise has vulcanization characteristics comparable to the comparative example (8*).

[0169] The vulcanizable compositions were subsequently vulcanized in a slab press under a pressure of 170 bar at 180C for 10 min.

[0170] The test values reported in Table 3 were determined at 23 C. on the vulcanizates that had been heat-treated at 160 C. for 4 hours.

TABLE-US-00004 TABLE 3 Properties of the vulcanized compositions 1 to 9 after vulcanization (10 minutes) at 180 C. (test temperature: 23 C.) Tensile test 1 2 3 4 5 6 7* 8* 9 2 mm slabs vulcanized at 180 C. for 10 min M 10 MPa 0.8 0.9 0.8 0.8 0.8 0.8 0.8 0.7 0.7 M 25 MPa 1.5 1.7 1.4 1.4 1.3 1.4 1.4 1.3 1.2 M 50 MPa 2.4 3.3 2.6 2.1 2 2 2.2 2.2 1.8 M 100 MPa 4.3 8.1 7.1 3.5 3.3 3.3 5.1 6.2 2.6 M 300 MPa 10.9 17.5 19.8 9 8.9 8.7 17.6 7.8 EB % 441 310 300 466 458 467 363 249 468 TS MPa 27 18 20 24 24 24 18 25.5 24.3 H ShA 68 69 69 66 66 65 70 71 61.8

[0171] The unaged comparative vulcanizate 7* has lower elongation at break and tensile strength than the inventive vulcanizates 4 to 6.

[0172] The unaged comparative vulcanizate 8* has significantly lower elongation at break coupled with the same tensile strength as the inventive vulcanizate 9.

[0173] The two comparative vulcanizates have a hardness (H) of 70 or more, whereas the inventive vulcanizates 1 to 6 and 9 have a hardness of less than 70.

TABLE-US-00005 TABLE 4 Properties of the vulcanized compositions 1 to 7 after hot air ageing at 150 C./504 h (test temperature: 23 C.) Tensile test 1 2 3 4 5 6 7* Ageing of the vulcanizates in hot air, 504 h at 150 C. M 10 MPa 1.2 1.2 1.1 1.2 1.2 1.2 1.3 M 25 MPa 2.4 2.6 2.3 2.5 2.5 2.5 2.5 M 50 MPa 4.9 5.5 5 5 5 5 4.8 M 100 MPa 8.6 10.9 10.9 9.2 9 9 10.4 M 300 MPa 14.1 16.4 14.1 13.7 13.6 EB % 375 233 254 383 396 429 228 TS MPa 18 15.4 17.1 17.5 17.4 19.4 18.5 H ShA 76 76 76 76 76 76 80

TABLE-US-00006 TABLE 5 Change in the properties of the vulcanized compositions 1 to 7 after hot air ageing at 150 C./504 h (test temperature: 23 C.) Change 1 2 3 4 5 6 7* Ageing of the vulcanizates in hot air, 504 h at 150 C. EB % 15 25 15 18 14 8 37 TS % 33 13 14 28 28 18 2 H ShA 8 8 7 10 11 11 10

[0174] Elongation at break (EB) in the case of comparative experiment 7 without silane-coated wollastonite is an inadequate value with a change of 37% after ageing in hot air for 504 hours. By contrast, the vulcanizates with silane-coated wollastonite of Examples 1 to 6 have a much smaller and hence better drop in elongation at break. The hardness (H) of the inventive examples is comparable with Comparative Example 7.

[0175] Example 6 with EST-coated wollastonite and without zinc has the smallest value with a change of 8% in elongation at break and hence gives the best hot air ageing.

TABLE-US-00007 TABLE 6 Properties of vulcanized compositions 8 and 9 and change therein after ageing in ethylene glycol/water/2-ethylhexanoic acid at 120 C./504 h (test temperature: 23 C.) Tensile test 8* 9 Ageing of the vulcanizates in ethylene glycol/water/2-ethylhexanoic acid, 504 h at 120 C. M 10 MPa 0.5 0.4 M 25 MPa 1 0.7 M 50 MPa 2.1 0.9 M 100 MPa 7.4 1.3 M 300 MPa 6 EB % 190 466 EB % 24 0 TS MPa 18.8 19 TS % 26 22 H ShA 57 47 H ShA 15 V % 47.1 19.1

[0176] Inventive Example 9 with silane-coated wollastonite, compared to Comparative Example 8* without silane-coated wollastonite, has a distinct improvement in elongation at break after ageing for 504 hours in an ethylene glycol/water/2-ethylhexanoic acid mixture.

[0177] In addition, Inventive Example 9 has improved swelling (AV).

TABLE-US-00008 TABLE 7 Comparison of the coatingsproperties of vulcanized compositions 1 to 3 after ageing at 150 C./1008 h in G13/water mixture (test temperature: 23 C.) Tensile test 1 2 3 Ageing of the vulcanizates in G13, 1008 h at 150 C. M 10 MPa 0.8 1 1 M 25 MPa 1.4 1.7 1.8 M 50 MPa 1.8 2.6 2.9 M 100 MPa 2.6 4.5 5.5 M 300 MPa 6.9 8.4 11.3 EB % 414 467 381 TS MPa 12.1 13.6 13.2 H ShA 71 70 72

TABLE-US-00009 TABLE 8 Comparison the properties of vulcanized of the coatingschange in compositions 1 to 3 after ageing at 150 C./1008 h in G13/water mixture (test temperature: 23 C.) Change 1 2 3 Ageing of the vulcanizates in G13, 1008 h at 150 C. EB % 6 51 27 TS % 55 23 33 H ShA 3 2 3 V % 19 20 10

[0178] Vulcanizates comprising VST-coated wollastonite, after ageing for 1008 hours in G13, have the best balance between change in elongation at break, volume swelling and change in tensile strength, and are thus better than vulcanizates comprising epoxysilane-coated wollastonite or methacryloylsilane-coated wollastonite.

TABLE-US-00010 TABLE 9 Properties of vulcanized compositions 4 to 7 after ageing at 150 C./504 h in G13/water mixture (test temperature: 23 C.) Tensile test 4 5 6 7* Ageing of the vulcanizates in G13, 504 h at 150 C. M 10 MPa 1.1 0.9 0.9 0.9 M 25 MPa 1.9 1.6 1.6 1.5 M 50 MPa 3 2.5 2.4 2.3 M 100 MPa 5.2 4.1 3.9 4.8 M 300 MPa 11 9.2 8.7 16 EB % 466 475 485 432 TS MPa 25.4 23.6 24.5 17.4 H ShA 72 69 68 72

TABLE-US-00011 TABLE 10 Change in the properties of vulcanized compositions 4 to 7* after ageing at 150 C./504 h in G13/ water mixture (test temperature: 23 C.) Change 4 5 6 7* Ageing of the vulcanizates in G13, 504 h at 150 C. EB % 0 4 4 19 TS % 5 2 4 4 H ShA 6 3 3 2 V % 3 3 3 1

[0179] Comparative Example 7*, with a change in elongation at break of 19% after ageing for 504 hours in G13, has the highest and hence worst value. Inventive Examples 4 to 6 have a distinctly smaller change in elongation at break.

TABLE-US-00012 TABLE 11 Composition of the vulcanizable composition 10 Example 10 Therban LT 1707 VP 100 Tremin 283-600 VST 35 N990 50 Luvomaxx CDPA 1.5 Vulkanox ZMB2 0.3 Maglite DE 3 Rhenofit TRIM/S 1.5 Perkadox 14-40 9

[0180] Vulcanization was measured in a Monsanto MDR 2000 rheometer at a test temperature of 180 C. over a test duration of 20 min.

TABLE-US-00013 TABLE 12 Vulcanization characteristics of the vulcanizable composition 10 MDR 180 C. 10 S min dNm 1.59 S max dNm 18.47 Delta S dNm 16.88 TS 1 s 36 TS 2 s 45 t 50 s 109 t 90 s 310 t 95 s 395 S@t 90 dNm 16.78 t@S max s 864

TABLE-US-00014 TABLE 13 Properties of the vulcanized composition 10 after vulcanization (10 minutes) at 180 C. (test temperature: 23 C.) Tensile test 10 2 mm slabs vulcanized at 180 C. for 10 min M 10 MPa 0.9 M 25 MPa 1.7 M 50 MPa 3.3 M 100 MPa 8.1 M 300 MPa 17.5 EB % 310 TS MPa 18 H ShA 69

[0181] The vulcanizate has a hardness of less than 70.

TABLE-US-00015 TABLE 14 Properties of the vulcanized composition 10 after hot air ageing at 150 C./504 h (test temperature: 23 C.) Tensile test 10 M 10 MPa 1 M 25 MPa 2.2 M 50 MPa 4.4 M 100 MPa 7.7 M 300 MPa EB % 246 TS MPa 11.2 H ShA 74

TABLE-US-00016 TABLE 15 Change in the properties of the vulcanized composition 10 after hot air ageing at 150 C./504 h (test temperature: 23 C.) Change 10 EB % 12 TS % 6.7 H ShA 13

TABLE-US-00017 TABLE 16 Properties of vulcanized composition 10 and change therein after ageing in Glysantin G64/ water at 150 C./504 h (test temperature: 23 C.) Tensile test 10 M 10 MPa 1.9 M 25 MPa 3.6 M 50 MPa 6 M 100 MPa 9.1 M 300 MPa 13.4 EB % 289 EB % 4 TS MPa 13.7 TS % 14.2 H ShA 78 H ShA 17 V % 3.5

[0182] Vulcanizates based on hydrogenated acrylate-comprising nitrile rubber comprising VST-coated wollastonite have a small change of elongation break of 12% after hot air aging and a small change of elongation break of 4% after aging in coolant (G64/water).