Patent DE-10008641-A1 (DE)
Title: Rubber composition for heavy duty automobile tire production comprises a vulcanizable rubber, a strengthened filler, a plasticizer and a specific amount of a sulfur compound
Inventor: YATSUYANAGI FUMITO
IPC: C08L81/04
Filed: 2000-02-24
Abstract: A rubber composition comprising a vulcanizable rubber, a strengthened filler, a plasticizer, other reagents, and a specific amount of sulfur compound is new. A rubber composition comprises a vulcanizable rubber, a strengthened filler, a plasticizer, other reagents, and a specific amount of a sulfur compound of formula (I): -(SxR1>)n- (I) R1>an organic group, x : an average number 3-5, and n : 1-100. The ratio (VM/VD) does not exceed 0.4, the value of VM is obtained from the extent of alteration before and after toluene swelling of the vulcanized rubber composition treated in a lithium aluminum hydride (LiAlH4)-saturated tetrahydrofuran/toluene solution (1/1 volume ratio) using the formula (A) where vrM = (1-phi )/(Xm-phi ), where Xmthe extent of alteration before and after toluene swelling (volume after toluene swelling/volume before toluene swelling) after treatment in a LiAlH4-saturated tetrahydrofuran/toluene (THF/T) solution (1/1 volume ratio), phi is the volume percent of the strengthened filler in the rubber composition, Vs = the toluene molecular volume, mu = the rubber-toluene interaction factor, and vrM = the volume percentage of the rubber in the swollen rubber after treatment with the LiAlH4-saturated solution (1/1 volume ratio), and a quantity VD obtained from the extent of alteration before and after toluene swelling of the vulcanized rubber composition, treated with propane-2-thiol (0.4 mole/liter)/piperidine (0.4 mole/liter) THF/T solution (1/1 volume ratio) using the formula (B) where vr(D+M) = (1-phi )/(X(D+M)-phi ), where X(D+M) is the extent of alteration before and after toluene swelling (volume after toluene swelling/volume before toluene swelling), after treatment with propane-2-thiol (0.4 mole/liter)/piperidine (0.4 mole/liter) THF/T solution (1/1 volume ratio), and vr(D+M) is the volume percentage of the rubber in the swollen rubber after treatment with propane-2-thiol (0.4 mole/liter)/piperidine (0.4 mole/liter) THF/T solution (1/2 volume ratio). VM = -1/Vs.[{ln(1-vrM)+vrM+mu .vrM2>}/{vrM1/3>-vrM/2}] (A) VD = -1/Vs.[{ln(1-vrD+M)+vrD+M+mu .vrD+M2>}/{vrD+M1/3>-vrD+M/2}-{ln (1-vrM)+vrM+mu .vrM2>}/{vrM1/3>-vrM/2}] (B) Independent claims are included for: (1) a vulcanized rubber composition including 100 parts by wt. of vulcanizable rubber, a strengthened filler, and a sulfur compound of formula (I) -(SxR1>)n- (I) R1>an organic group, x : an average number 3-5, and n : 1-100, in amount not exceeding 20 parts by wt., or sulfur compounds (I) and (II) in (I)/(II) ratio not less than 0.5, total weight of (I)+(II) not exceeding 20 parts by wt., vulcanized by mixing at least one vulcanization accelerator (III), selected from: thiazole, sulfamide, thiuram, and dithioacid based accelerators, so that the total weight [(I)/(II)]/(III) does not exceed 2.2. The quantity VM is obtained from the extent of alteration before and after toluene swelling of the vulcanized rubber composition treated in an LiALH4 saturated tetrahydrofuran/toluene solution (1/1 volume ratio) using formula (A), where R1>, x, n, VM = as above, and vrM = the volume percent of rubber in the swollen rubber composition after treatment with LiALH4 and propane-2-thiol/piperidine etc. as above using the formula (D) where vr(D+M) = as above. A quantity VT is obtained from the extent of alteration before and after toluene swelling of the untreated vulcanized rubber composition using the formula (C) where vrT = (1-phi )/(XT-phi ), where XTthe extent of alteration before and after toluene swelling when not treated (volume after toluene swelling/volume before toluene swelling), vrTthe volume percent of rubber in the swollen untreated rubber, so that VM/VT = not more than 0.3 and (VT-V[D+M])/VT = at least 0.4, and the extent of retention of the breaking strength and elongation at break before and after heat treatment at 100[deg]C for 96 hours is at least 70% VT = -1/Vs.[{ln(1-vrT)+vrT+mu .vrT2>}/{vrT1/3>-vrT/2}] (C) V(D+M) = -1/Vs.[{ln(1-vrD+M)+vrD+M+mu .vrD+M2>}/{vrD+M1/3>-vrD+M/2}] (D) (2) a rubber composition for heavy duty tire running surfaces including 100 parts by wt. of diene rubber, 40-85 parts by wt. of strengthened filler, 1-10 parts by wt. of at least one resin selected from rosin-, cyclopentadiene resin-based resins and their mixtures, a sulfur compound of formula (I) or (II) where n' = 3 or 4. [Image]