Rubber mixtures

Abstract

The invention relates to rubber mixtures, said rubber mixtures comprising (a) at least one rubber, excluding silicone rubber, chloroprene rubber, bromobutyl rubber, fluoro rubber and nitrile rubber, (b) at least one silane of general formula (I),
G-Si(OR).sub.3(I), (c) at least one amine compound selected from the list triethanolamine, triisopropanolamine and [HOCH(phenyl)CH.sub.2].sub.3N and (d) at least one bifunctional silane. The rubber mixture is produced by mixing the rubber, silane of general formula (I), amine compound and bifunctional silane.

Claims

1. A rubber mixture, comprising: (a) a rubber, excluding silicone rubber, chloroprene rubber, bromobutyl rubber, fluoro rubber and nitrile rubber; (b) CH.sub.3CH.sub.2CH.sub.2Si(OCH.sub.2CH.sub.3).sub.3 as a silane; (c) at least one amine compound selected from the group consisting of triethanolamine, triisopropanolamine and [HOCH(phenyl)CH.sub.2].sub.3N; and (d) a bifunctional silane, wherein the silane is present from 0.8 to 4 parts by wt based on 100 parts by wt of the rubber, the bifunctional silane is present in an amount of from 5 to 9 parts by wt based on 100 parts by wt of the rubber, and wherein the bifunctional silane is vinyltriethoxysilane, vinyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, or methacryloxypropyltrimethoxysilane.

2. The rubber mixture according to claim 1, further comprising: a filler; and optionally additional rubber auxiliaries.

3. The rubber mixture according to claim 1, wherein the at least one amine compound is present in an amount of from 0.1 to 8 parts by wt based on 100 parts by wt of the rubber.

4. The rubber mixture according to claim 1, wherein the rubber is a diene rubber.

5. The rubber mixture according to claim 1, wherein the at least one amine compound is triethanolamine.

6. The rubber mixture according to claim 1, wherein the at least one amine compound is triisopropanolamine.

7. A process for producing the rubber mixture according to claim 1, the process comprising: mixing: (a) the rubber, excluding silicone rubber, chloroprene rubber, bromobutyl rubber, fluoro rubber and nitrile rubber, (b) the silane, (c) the at least one amine compound, and (d) the bifunctional silane.

8. A production method comprising: producing moulded articles using the rubber mixture according to claim 1.

9. The production method according to claim 8, wherein the moulded articles are selected from the group consisting of pneumatic tires, tire treads, rubber-containing tire components, cable sheathings, hoses, drive belts, conveyor belts, roller coverings, tires, shoe soles, sealing rings and damping elements.

10. A rubber mixture, comprising: (a) a rubber, excluding silicone rubber, chloroprene rubber, bromobutyl rubber, fluoro rubber and nitrile rubber; (b) CH.sub.3CH.sub.2CH.sub.2Si(OCH.sub.2CH.sub.3).sub.3 as a silane; (c) [HOCH(phenyl)CH.sub.2].sub.3N; and (d) a bifunctional silane, wherein the silane is present from 0.8 to 4 parts by wt based on 100 parts by wt of the rubber, and the bifunctional silane is present in an amount of from 5 to 9 parts by wt based on 100 parts by wt of the rubber.

Description

EXAMPLES

Example 1: Rubber Tests

(1) The formulation used for the rubber mixtures is specified in tables 1a and 1b which follow. The unit phr means parts by weight based on 100 parts of the raw rubber used. The silanes of general formula I are employed in equimolar amounts, i.e. the amount of substance is equal.

(2) TABLE-US-00001 TABLE 1a inventive inventive inventive inventive comparative comparative comparative mixture 4 mixture 5 mixture 6 mixture 7 stage 1 mixture 1 (phr) mixture 2 (phr) mixture 3 (phr) (phr) (phr) (phr) (phr) Buna VSL 4526-2.sup.a 96.3 96.3 96.3 96.3 96.3 96.3 96.3 Buna CB 24.sup.b 30.0 30.0 30.0 30.0 30.0 30.0 30.0 ULTRASIL 7000 GR.sup.c 80.0 80.0 80.0 80.0 80.0 80.0 80.0 Si 266.sup., d 5.8 5.8 5.8 5.8 5.8 5.8 5.8 Corax N 330.sup.e 5.0 5.0 5.0 5.0 5.0 5.0 5.0 ZnO.sup.f 2.0 2.0 2.0 2.0 2.0 2.0 2.0 fatty acid.sup.g 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Vivatec 500.sup.h 8.8 8.8 8.8 8.8 8.8 8.8 8.8 Protektor G 3108.sup.i 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Vulkanox 4020/LG.sup.j 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Vulkanox HS/LG.sup.k 1.5 1.5 1.5 1.5 1.5 1.5 1.5 triethanolamine.sup.l 1.4 1.4 1.4 1.4 1.4 Rhenogran DPG-80.sup.m 2.5 organosilicon compound 1.6 1.sup.n organosilicon compound 1.9 2.sup.o organosilicon compound 1.5 3.sup.p organosilicon compound 1.9 4.sup.q organosilicon compound 2.2 5.sup.r

(3) TABLE-US-00002 TABLE 1b stage 2 stage 1 batch stage 3 stage 2 batch Perkacit TBzTD.sup.s 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Vulkacit CZ/EG-C.sup.t 1.6 1.6 1.6 1.6 1.6 1.6 1.6 sulphur.sup.u 2.0 2.0 2.0 2.0 2.0 2.0 2.0
Substances Used:
a) Buna VSL 4526-2: solution-polymerized SBR copolymer from Lanxess AG (styrene content=26 wt %, vinyl content=44.5 wt %, TDAE oil content=27.3 wt %, Mooney viscosity (ML 1+4/100 C.)=50 MU).
b) Buna CB 24: solution-polymerized high cis-1,4-polybutadiene (neodymium catalyst) from Lanxess AG (cis-1,4 content=min. 96%, Mooney viscosity (ML 1+4/100 C.) 44 MU).
c) Silica: ULTRASIL 7000 GR from Evonik Industries AG (easily dispersible precipitated silica, BET surface area=170 m.sup.2/g, CTAB surface area=160 m.sup.2/g).
d) Si 266: bis(triethoxysilylpropyl)disulphide from Evonik Industries AG.
e) Corax N 330: ASTM carbon black from Orion Engineered Carbons GmbH.
f) ZnO: RS RAL 844 C ZnO zinc oxide from Arnsperger Chemikalien GmbH.
g) EDENOR ST1 fatty acid mixture (C.sub.16/C.sub.18) from Caldic Deutschland Chemie B.V.
h) Vivatec 500: TDAE oil from H&R AG.
i) Protektor G3108: antiozonant wax composed of refined hydrocarbons (freezing point=57 C.) from Paramelt B.V.
j) Vulkanox 4020/LG: N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine (6PPD) from Rhein Chemie Rheinau GmbH.
k) Vulkanox HS/LG: polymeric 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) from Rhein Chemie Rheinau GmbH.
l) Triethanolamine from BASF SE.
m) Rhenogran DPG-80: 80% N,N-diphenylguanidine (DPG) on 20% elastomeric carrier and dispersant from Rhein Chemie Rheinau GmbH.
n) Organosilicon compound 1: Dynasylan MTES (methyltriethoxysilane) from Evonik Industries AG.
o) Organosilicon compound 2: Dynasylan PTEO (propyltriethoxysilane) from Evonik Industries AG.
p) Organosilicon compound 3: Dynasylan PTMO (propyltrimethoxysilane) from Evonik Industries AG.
q) Organosilicon compound 4: allyltriethoxysilane from abcr GmbH.
r) Organosilicon compound 5: triethoxyphenylsilane from TCI Europe N.V.
s) Perkacit TBzTD: tetrabenzylthiuram disulphide (TBzTD) obtained from Weber & Schaer (producer: Dalian Richon).
t) Vulkacit CZ/EG-C: N-cyclohexyl-2-benzothiazolesulphenamide from Rhein Chemie Rheinau GmbH.
u) Sulphur: Mahlschwefel 80/90 from Solvay & CPC Barium Strontium GmbH & Co. KG.

(4) The mixtures are prepared in three stages in a 1.5 L internal mixer (E-type) at a batch temperature of 155 C. in accordance with the mixing instructions in table 2.

(5) The general process for preparing rubber mixtures and vulcanizates thereof is described in the book: Rubber Technology Handbook, W. Hofmann, Hanser Verlag 1994.

(6) TABLE-US-00003 TABLE 2 stage 1 settings mixing unit HF mixing group GmbH; type GK 1.5 E fill level 0.65 Speed 80 rpm ram pressure 5.5 bar Flow temp. 80 C. mixing operation 0 to 0.5 min rubbers 0.5 to 1.0 min 6PPD, TMQ 1.0 to 2.0 min of silica, Si 266, ZnO, fatty acid 2.0 min vent and purge 2.0 to 3.0 min of silica, carbon black, TDAE oil, antiozonant wax, if present: DPG-80 or organosilicon compound 1-5 and triethanolamine 3.0 min vent 3.0 to 5.0 min mix at 155 C., optionally adjusting temperature by varying rotational speed 5.0 min discharge batch and form milled sheet on laboratory mixing roll mill for 45 s (laboratory roll mill: diameter 250 mm, length 190 mm, roll gap 4 mm, flow temperature 60 C.) 23 h storage at room temperature stage 2 settings mixing unit as in stage 1 except fill level 0.62 Speed 95 rpm Flow temp. 90 C. mixing operation 0 to 1.0 min break up stage 1 batch 1.0 to 3.0 min mix at 155 C., optionally adjusting temperature by varying rotational speed 3.0 min discharge batch and form milled sheet on laboratory mixing roll mill for 45 s (laboratory roll mill: diameter 250 mm, length 190 mm, roll gap 4 mm, flow temperature 60 C.) 3 h storage at room temperature stage 3 settings mixing unit as in stage 1 except fill level 0.59 Speed 55 rpm Flow temp. 50 C. mixing operation 0 to 2.0 min break up stage 2 batch, accelerant and sulphur, mix at 100 C., optionally adjusting temperature by varying speed 2.0 min discharge batch and form milled sheet on laboratory mixing roll mill for 20 s (laboratory roll mill: diameter 250 mm, length 190 mm, roll gap 4 mm, flow temperature 80 C.)

(7) Vulcanization is effected at a temperature of 165 C. in a typical vulcanizing press with a holding pressure of 120 bar after t.sub.95%. The t.sub.95% time is determined by means of a moving die rheometer (rotorless vulcameter) as per ISO 6502 (section 3.2 rotorless curemeter) at 165 C.

(8) The rubber testing is effected in accordance with the test methods specified in table 3.

(9) TABLE-US-00004 TABLE 3 physical testing standard/conditions Mooney viscosity ML 1 + 4 at 100 C. ISO 289-1 Mooney viscosity/MU moving die rheometer (MDR) at ISO 6502, section 3.2 145 C., 1.67 Hz, 0.5 = 7% rotorless curemeter t.sub.10/min t.sub.20/min rod tensile test at 23 C. ISO 37 reinforcement index modulus 300%/100%

(10) Table 4 reports the rubber data for the crude mixtures and vulcanizates.

(11) TABLE-US-00005 TABLE 4 comparative comparative comparative inventive inventive inventive inventive mixture 1 mixture 2 mixture 3 mixture 4 mixture 5 mixture 6 mixture 7 Raw mixture results: Mooney viscosity ML 1 + 4 at 100 C. Mooney viscosity/MU stage 1 86 100 83 96 86 91 82 stage 2 64 79 68 65 69 67 65 stage 3 52 60 53 52 54 53 51 moving die rheometer (MDR) at 165 C., 1.67 Hz, 0.5 = 7% torque (M.sub.max M.sub.min)/dNm 11.3 11.6 11.5 12.1 12.3 11.8 12.1 t.sub.10/min 3.3 3.7 4.4 4.1 4.3 4.2 4.4 t.sub.20/min 3.8 4.5 5.4 5.2 5.5 5.2 5.3 t.sub.90/min 9.2 19.7 11.5 11.9 11.5 10.6 10.6 vulcanizate results: rod tensile test at 23 C. 5.2 5.0 4.8 5.0 5.0 5.2 5.2 reinforcement index: 300%/100% stress value

(12) Compared to comparative mixture 2 the effect of the secondary accelerators is evidenced in all other mixtures by reduced vulcanization times (MDR, t.sub.90% values) and improved processing (Mooney viscosities). Compared to the comparative mixtures 1 and 2 the combination of silane and triethanolamine in the inventive mixtures 4, 5, 6 and 7 and the comparative mixture 3 additionally achieves improved processing consistency (MDR, t.sub.10% and t.sub.20% values).

(13) The inventive mixtures 4, 5, 6 and 7 further result in improved crosslinking density (MDR, A torque (M.sub.maxM.sub.min)) compared to comparative mixtures 1, 2 and 3. The inventive mixtures 4, 5, 6 and 7 moreover achieve the intended reinforcing effect of comparative mixtures 1 and 2 which is improved over that of comparative mixture 3.