MODIFIED SILICAS, PROCESS FOR PREPARATION THEREOF AND USE THEREOF

Abstract

Modified silicas, having the following physicochemical parameters: a CTAB.sub.mod of <200 m.sup.2/g, a BET.sub.MP of 50-500 m.sup.2/g, a CTAB.sub.mod-BET.sub.MP of <0 m.sup.2/g, a carbon content of >0.5% by weight, a mode.sub.mod from CPS particle size determination of >50 nm, a d75.sub.mod from CPS particle size determination of 20-150 nm, a R.sub.min from Hg pore size determination, pressurized of <10 nm, and a sulfur content of ≤1.50% by weight.

Claims

1. Modified silicas, having the following physicochemical parameters: a CTAB.sub.mod of <200 m.sup.2/g, a BET.sub.MP of 50-500 m.sup.2/g, a CTAB.sub.mod-BET.sub.MP of <0 m.sup.2/g, a carbon content of >0.5% by weight, a mode.sub.mod from CPS particle size determination of >50 nm, a d75mod from CPS particle size determination of 20-150 nm, a R.sub.min from Hg pore size determination, pressurized of <10 nm, and a sulfur content of ≤1.50% by weight.

2. The modified silicas of claim 1, wherein the modified silica is a modified precipitated silica.

3. The modified silicas of claim 1, wherein the sulfur content is 0.40% to 1.50% by weight.

4. The modified silicas of claim 1, that having an Ro-Tap (>300 μm) of >50%.

5. The modified silicas of claim 1, having a drying loss of <4.5% by weight.

6. The modified silicas of claim 1, having a pH of >6.3.

7. The modified silicas of claim 1, having a TAR.sub.mod value of >1%.

8. The modified silicas of claim 1, having an ignition residue of 70-95%.

9. The modified silicas of claim 1, having an IF value from Hg pore size determination, pressurized, of <170 Å.

10. The modified silicas of claim 1, having an IS value from Hg pore size determination, pressurized, of <79 ml/(100 g).

11. The modified silicas of claim 1, having a PV value (V80, 3.7-80 nm, 140°) of <0.86 ml/g.

12. A process for preparing the modified silicas of claim 1, comprising: mixing silica with at least one additive selected from the group consisting of aqueous sulfur-containing alkoxysilane emulsion, polysiloxane, mixture of sulfur-containing alkoxysilane and polysiloxane, and mixture of sulfur-containing alkoxysilane and anionic polyether, in an intake of a drying unit to form a mixture, and supplying the mixture to the drying unit.

13. The process for preparing the modified silicas of claim 12, wherein the sulfur-containing alkoxysilane is bis[(3-triethoxysilyl)propyl] disulfide or (EtO).sub.3Si—(CH.sub.2).sub.3—S—C(O)—C.sub.7H.sub.15.

14. The process for preparing the modified silicas of claim 12, wherein the polysiloxane is a modified polydimethylsiloxane having polyether phosphate, alkyl ester or polyether groups.

15. The process for preparing the modified silicas of claim 12, wherein a reaction is performed in a Henschel mixer or spin-flash dryer.

16. A rubber mixture comprising: (A) a rubber or a mixture of rubbers; and (B) the modified silicas of claim 1.

17. A process for producing the rubber mixture of claim 16, wherein the rubber or mixture of rubbers, the modified silicas as claimed in claim 1 and optionally further rubber auxiliaries are mixed in a mixing unit.

18. A product comprising the rubber mixture of claim 16, selected from the group consisting of pneumatic tyres, cable sheaths, hoses, drive belts, conveyor belts, roll coverings, tyres, footwear soles, gasket elements and damping elements.

Description

EXAMPLES

[0254] The reference silicas used are the silicas or modified silicas that follow (Table 1). The unit phf (parts per hundred filler) means parts by weight of additive based on 100 parts by weight of silica:

[0255] Silica 1 is ULTRASIL® 9100 GR from Evonik Resource Efficiency GmbH.

[0256] Silica 2 is prepared according to Example 1 from EP 1525159 B1.

[0257] Silica 3 is ULTRASIL® 7000 GR from Evonik Resource Efficiency GmbH.

[0258] Silica 4 is ZEOSIL® Premium 200 MP from Solvay.

[0259] Silica 5 is ZEOSIL® 1165 MP from Solvay.

[0260] Silica 6 is prepared according to Example 4 from EP 0901986 B1.

[0261] Silica 7 is Ciptane™ LP from PPG Industries Ohio, Inc.

[0262] Silicas 8+9 are Agilon® 400 and Agilon® 458 from PPG Industries Ohio, Inc.

[0263] Silica 10 is prepared according to Example 1 from WO2014033300 A1.

[0264] Silica 11 is COUPSIL® 8113 GR from Evonik Resource Efficiency GmbH.

[0265] Silica 12 is based on Example 4 silica from EP 0901986 B1, modified with 5 phf Si 69®.

[0266] Silica 13 is based on Example 4 silica from EP 0901986 B1, modified with 10 phf Si 69®.

TABLE-US-00007 TABLE 1 Silica 1 2 3 4 5 6 7 8 9 10 11 12 13 Additives — — — — — — 0.33% by COUP weight of SIL ® Al + 1.1% 8113 by weight GR of DBA based on SiO.sub.2 Drying loss % 5.9 4.3 4.8 5.1 6.4 4.0 5.6 4.3 5.5 3.9 3.6 1.9 2.3 pH — 6.7 6.9 6.7 6.0 6.4 6.8 7.0 6.1 6.0 5.3 6.6 7.0 7.1 BET.sub.MP m.sup.2/g 228 235 170 206 153 165 76 77 113 150 128 146 133 CTAB m.sup.2/g 202 201 158 203 159 156 CTAB.sub.mod. m.sup.2/g 123 124 98 126 95 90 87 125 96 82 91 85 CTAB.sub.mod. − −105 −111 −72 −80 −58 −165 14 10 12 −54 −46 −55 −48 BET.sub.MP DOA, ml/ 209 225 200 208 202 212 191 197 164 198 126 184 174 original (100 g) TAR.sub.mod % 22.0 23.7 15.6 16.8 24.3 TAR % 20.7 21.2 17.6 22.5 C content % <0.1 <0.1 0.1 <0.1 <0.1 <0.1 4.2 4.2 6.3 0.5 4.2 1.8 3.4 Sulfur % 0.20 0.14 0.21 0.37 0.28 0.13 0.70 0.70 0.80 0.28 3.67 1.79 2.78 content Ignition % 90.6 92.0 91.7 91.1 89.2 92.7 90.6 86.5 84.0 92.8 86.8 90.7 88.4 residue Mode from nm 77 80 87 85 81 86 CPS d75 from nm 63 66 77 68 68 71 CPS Mode.sub.mod nm 75 104 79 80 75 80 79 from CPS d75.sub.mod nm 60 92 67 65 62 62 64 from CPS IF (140°, Å 87.9 77.5 106.5 86.9 111.1 118.0 102.5 203.3 123.4 116.4 107.7 113.9 111.0 dV/dR) IS (90%, ml/ 81.0 76.9 73.3 88.1 76.6 83.0 72.3 72.4 68.9 82.5 69.9 75.2 70.3 140°, (100 g) dV/dR) PV (V80, ml/g 0.90 0.84 0.80 0.98 0.87 0.92 0.83 0.74 0.75 0.90 0.77 0.81 0.78 3.7 − 80 nm, 140°) R.sub.min (90%, nm 3.45 1.75 2.67 1.52 4.52 3.04 4.09 7.07 5.65 4.12 3.62 3.73 4.84 140°, dV/dR)

[0267] Inventive silicas 14-21 are produced by preliminary mixing of the starting silica and the additives in a conveying screw, followed by drying in a Henschel mixer (Henschel FM 40 fluid mixer from Thyssen). For Examples 14-21, 3000 g of the starting silica that had been prepared according to Example 4 from EP 0901986 B1 was used. The additives are used in accordance with the recipe (Table 2). The mixer is preheated to 100° C. After the silica/additive mixture has been fed in, it is dried in the Henschel mixer at 2500 rpm for a period of 4 min.

[0268] In Examples 14, 16, 18 and 20, the modified silica was then compacted in a roll compactor.

[0269] Table 2 shows the composition of the modified silicas according to the invention. The unit phf (parts per hundred filler) means parts by weight of additive based on 100 parts by weight of silica. Si 266® is bis[(3-triethoxysilyl)propyl] disulfide from Evonik Resource Efficiency GmbH. NXT is (EtO).sub.3Si—(CH.sub.2).sub.3—S—C(O)—C.sub.7H.sub.15 from Momentive.

TABLE-US-00008 TABLE 2 Example Composition 14/15 Silica from Example 4 of EP 0901986 B1 + 8.0 phf Si 266 ® + 17.3 phf anionically modified polyether (TEGOMER ® DA 640) 16/17 Silica from Example 4 of EP 0901986 B1 + 8.0 phf Si 266 ® + 11.6 phf alkyl-modified polysiloxane (TEGOPREN ® 6875-45) 18/19 Silica from Example 4 of EP 0901986 B1 + 8.0 phf Si 266 ® + 5.2 phf polyether-modified polysiloxane (TEGOPREN ® 5885) 20/21 Silica from Example 4 of EP 0901986 B1 + 9.0 phf NXT silane + 17.3 phf anionically modified polyether (TEGOMER ® DA 640)

[0270] Table 3 shows the analytical data of the modified silicas according to the invention.

TABLE-US-00009 TABLE 3 Silicas 14 15 16 17 18 19 20 21 Additives 8 phf 8 phf 8 phf 8 phf 8 phf 8 phf 9 phf NXT 9 phf NXT Si 266 Si 266 Si 266 Si 266 Si 266 Si 266 silane silane 5.2 phf 5.2 phf 11.6 phf 11.6 phf 5.2 phf 5.2 phf 5.2 phf 5.2 phf TEGOMER TEGOMER TEGOPREN TEGOPREN TEGOPREN TEGOPREN TEGOMER TEGOMER DA 640 DA 640 6875-45 6875-45 5585 5585 DA 640 DA 640 Drying loss % 3.4 3.5 3.0 3.6 2.7 3.5 3.0 2.9 pH — 7.2 7.2 7.1 7.1 7.1 7.1 7.6 7.6 BET.sub.MP m.sup.2/g 129 122 100 95 116    108    106 105 CTAB.sub.mod. m.sup.2/g 72 74 78 66 72   68   82 78 CTAB.sub.mod. − m.sup.2/g −57 −48 −22 −29 −44   −40   −24 −27 BET.sub.MP DOA, ml/ 152 179 142 159 148    170    154 192 original (100 g) TAR.sub.mod % 49.0 44.0 54.7  37.0 C content % 3.1 3.1 5.5 5.5 4.2 4.2 6.0 6.0 Sulfur % 1.27 1.27 1.23 1.23  1.23  1.23 0.95 0.95 content Ignition % 89.4 90.7 87.1 88.6 88.6  90.2  85.7 85.7 residue Mode.sub.mod nm 78 82 78 82 78   82   75 82 from CPS d75.sub.mod nm 66 70 66 71 66   71   60 67 from CPS IF (140°, Å 136.0 119.0 125.7 138.1 114.5  115.9  115.1 112.5 dV/dR) IS (90%, ml/ 70.0 69.0 77.6 67.4 69.9  67.4  65.8 60.0 140°, (100 g) dV/dR) PV (V80, ml/g 0.76 0.76 0.84 0.73  0.77  0.73 0.71 0.65 3.7 − 80 nm, 140°) R.sub.min (90%, nm 4.78 4.10 3.72 4.09  3.40  3.75 3.26 4.32 140°, dV/dR)

[0271] Modified silicas 22-29 according to the invention are produced in a spin-flash dryer. The base silicas for modification are prepared according to Example 4 from EP 0901986 B1 and Example 1 from EP 1525159 B1. The filtercake obtained is conveyed into the spin-flash dryer by means of a conveying screw. The additive is added via a conduit into the conveying unit, before the mixture thus obtained is metered into the drying chamber. The dried silicas are optionally pelletized.

[0272] The silicone oil used is Dow Xiameter™ PMX-200 Silicone Fluid polydimethylsiloxane having a viscosity of 50 cSt.

[0273] Table 4 shows the analytical data of the modified silicas.

TABLE-US-00010 TABLE 4 Silicas 22 23 24 25 26 27 28 29 Additives 5 phf 8 phf 2 phf 15 phf 2.7 phf 2.7 phf 5 phf 8 phf silicone silicone silicone aqueous Si 266/5.3 phf Si 266/5.3 phf silicone silicone oil oil oil/1 phf Si 266 silicone oil silicone oil oil oil Si 266 emulsion Drying loss % 3.9 3.6 3.6 3.0 3.5 3.5 3.3 3.1 pH — 7.2 7.1 7.1 6.4 7.3 7.5 6.7 6.7 BET.sub.MP m.sup.2/g 185 163 209 145 163 85 116 106 CTAB.sub.mod. m.sup.2/g 109 104 120 85 105 63 87 83 CTAB.sub.mod. − m.sup.2/g −76 −59 −28 −60 −58 −22 −29 −23 BET.sub.MP DOA, ml/ 178 171 209 189 191 146 185 177 original (100 g) TAR.sub.mod. % 19.2 20.5 23.7 20.4 22.9 27.3 16.4 16.4 C content % 1.5 2.3 1.1 1.6 2.1 2.3 1.6 2.5 Sulfur % 0.12 0.14 0.30 1.15 0.44 0.41 0.20 0.20 content Ignition % 91.8 91.4 92.3 91.3 91.3 90.6 92.9 91.2 residue Mode.sub.mod nm 72 71 72 80 73 78 78 83 from CPS d75.sub.mod nm 59 57 60 64 61 67 63 61 from CPS IF (140°, Å 82.8 82.1 73.1 119.7 86.9 154.4 116.0 121.0 dV/dR) IS (90%, ml/ 76.5 72.8 71.6 76.8 72.7 73.4 73.0 72.0 140°, (100 g) dV/dR) PV (V80, ml/g 0.76 0.76 0.84 0.73 0.77 0.73 0.71 0.65 3.7 − 80 nm, 140°) R.sub.min (90%, nm 2.29 2.96 2.67 4.53 2.63 5.11 3.90 3.27 140°, dV/dR)

[0274] Examination of Rubber Characteristics

[0275] The materials used for the rubber mixtures are listed in Table 5. A further reference silica used was ULTRASIL® VN 3 GR from Evonik Resource Efficiency GmbH.

[0276] The recipes are shown in Table 6.

TABLE-US-00011 TABLE 5 List of materials used In the examples SSBR BUNA ® VSL 4526-2, Arlanxeo Deutschland GmbH BR BUNA ® CB 24, Arlanxeo Deutschland GmbH Reference ULTRASIL ® 7000 GR, Evonik Resource Efficiency GmbH silicas ULTRASIL ® VN 3 GR, Resource Efficiency GmbH ZEOSIL ® 1165 MP, Solvay Silanes Si 266 ®, Evonik Resource Efficiency GmbH NXT, Momentive Performance Materials Inc. Additives TEGOPREN ® 5885, TEGOPREN ® 6875-45, TEGOMER ® DA 640, Evonik Nutrition & Care GmbH ZnO Rotsiegel zinc oxide, Grillo Zinkoxid GmbH Stearic Edenor ST1, Caldic Deutschland GmbH acid Oil Vivatec 500, Hansen & Rosenthal KG Wax Protektor G 3108, Paramelt B.V. PPD Vulkanox ® 4020/LG, Rhein-Chemie GmbH TMQ Vulkanox ® HS/LG, Rhein-Chemie GmbH DPG Rhenogran ® DPG-80, Rhein-Chemie GmbH CBS Vulkacit ® CZ/EG-C, Rhein-Chemie GmbH Sulfur ground sulfur, Azelis S.A. TBzTD Richon TBzTD OP, Weber & Schaer GmbH & Co. KG

TABLE-US-00012 TABLE 6 Mixture formulation of the S-SBR/BR mixture Reference Reference Reference Mixture 1 2 3 4 5 6 7 Stage 1 SSBR 96.3 96.3 96.3 96.3 96.3 96.3 96.3 BR 30 30 30 30 30 30 30 Inv. mod. silica 15 90.6 — — — — — — Inv. mod. silica 21 — 91.4 — — — — — Inv. mod. silica 19 — — 90.6 — — — — Inv. mod. silica 17 — — — 90.6 — — — ULTRASIL VN 3 GR — — — — 80 — — Silica 5 — — — — — 80 — Silica 6 — — — — — — 80 Si 266 — — — — 6.4 6.4 6.4 ZnO 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Stearic acid 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Oil 8.75 8.75 8.75 8.75 8.75 8.75 8.75 Wax 2.0 2.0 2.0 2.0 2.0 2.0 2.0 PPD 2.0 2.0 2.0 2.0 2.0 2.0 2.0 TMQ 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Stage 2 Stage 1 batch DPG 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Stage 3 Stage 2 batch CBS 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Sulfur 2.14 2.2 2.14 2.14 2.14 2.14 2.14 TBzTD 0.2 0.2 0.2 0.2 0.2 0.2 0.2

[0277] The rubber mixtures were produced with a GK 1.5 E internal mixer from Harburg Freudenberger Maschinenbau GmbH (Table 7).

TABLE-US-00013 TABLE 7 Mixture production of the S-SBR/BR mixture Stage 1 Intermix 1.5 E temp. 65° C., 70 rpm Batch temp.: 140-155° C. 0.0-0.5 min Polymers 0.5-1.0 min TMQ, 6PPD, ⅓ filler 1.0-2.0 min ⅓ filler, any silane, ZnO, stearic acid 2.0-2.0 min Vent, purge 2.0-3.0 min a) premix carbon black and oil and add together b) 1/3 filler c) remaining constituents from the first stage 3.0-3.0 min Vent 3.0-5.0 min Mix at 140-155° C., optionally varying speed Eject About 45 s, on the roll (4 mm gap), eject sheet Storage: 24 h/RT Stage 2 Intermix 1.5 E temp. 70° C., 70 rpm Batch temp.: 140-155° C. 0.0-1.0 min Stage 1 batch 1.0-3.0 min DPG, mix at 140-155° C., optionally varying speed 3.0-3.0 min Eject About 45 s, on the roll (4 mm gap), eject sheet Storage: 24 h/RT Stage 3 Intermix 1.5 E temp. 50° C., 50 rpm Batch temp.: 90-110° C. 0.0-2.0 min Stage 2 batch, accelerator, sulfur 2.0-2.0 min Eject and process on the roll for about 20 s, with gap 3-4 mm Storage: 12 h/RT

[0278] The results of physical tests on the rubber mixtures specified here or vulcanizates thereof are listed in Table 8. The vulcanizates were produced from the untreated mixtures from the third stage by heating at 165° C. for 15 min under 130 bar. The measurements on the rubber mixtures were made by the methods described in Table 9.

TABLE-US-00014 TABLE 8 Results of physical tests on the rubber mixtures specified here and their vulcanizates Reference Reference Reference Mixture 1 2 3 4 5 6 7 Untreated mixture M.sub.S(1 + 4) 100° C. 36 34 36 37 45 47 42 stage 2/ME M.sub.L(1 + 4) 100° C. 49 43 51 52 55 53 52 stage 3/ME RPA; M.sub.L/dNm 5.9 4.9 5.6 6.2 6.7 6.6 6.5 MDR; t10% 1.4 1.2 2.0 1.7 0.6 1.2 1.5 t90%/min 3.4 3.4 3.9 3.9 4.7 4.4 4.6 Vulcanizate DIN abrasion/mm.sup.3 80 76 100 88 84 81 84 Tensile strength at 23° C./MPa 16.5 16.2 16.0 15.4 13.5 16.5 16.4 Elongation at break at 23° C./% 426 444 444 406 374 394 398 Tensile strength at 60° C./MPa 9.4 9.7 10.2 8.8 9.9 8.4 9.9 RPA, tan δ (max.) 0.123 0.131 0.131 0.115 0.136 0.142 0.134 Dispersion/% 97.5 96.9 96.1 96.9 88.7 96.9 97.3

[0279] As apparent from Table 8, the mixtures according to the invention (1-4), compared to the references (5-7), have improved processing characteristics, as demonstrated by the reduced Mooney viscosities (mixing stages 2 and 3) and the reduction in minimum torque ML (mixing stage 3). The times at conversion t10% and t90% after mixing stage 3 also demonstrate an extended processing window with optimized vulcanization conversion. In addition, the mixtures according to the invention (1-4) show improved elongation at break with the same tensile strength compared to the reference mixtures (5-7). The dynamic properties of the vulcanized mixtures according to the invention are at a better level than those of the references (5-7), with simultaneously good abrasion properties (mixtures 1, 3 and 4) and dispersion quality.

TABLE-US-00015 TABLE 9 Method Standard Mooney viscometer ISO 289 Mixture viscosity (ME) Moving die rheometer DIN 53529 Time at conversion t 10%, t 90% (min) Rubber process analyser (RPA) vulcanization isotherm ASTM D7605 Min. torque M.sub.L (dNm) at 165° C., 1.6 Hz, 42% Vulcanizate strain sweep: tan δ (max.) at 60° C., 1.6 Hz, 0.28-42% Tensile strain on S1 test specimens at 23° C. and 60° C. DIN 53 504 Tensile strength (MPa) Elongation at break (%) Abrasion test (mm.sup.3) DIN ISO 4649 ASTM D5963 Dispersion quality of the fillers in vulcanizates (%) ISO 11345 DisperTester 3000 plus (100x)