Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-04-16
2001-08-21
Niland, Patrick D. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C152S450000, C152S905000, C524S609000, C524S881000, C524S858000, C524S791000, C524S790000, C524S783000, C524S779000, C524S788000, C524S837000, C528S010000, C528S025000, C528S026000, C528S027000, C528S042000
Reexamination Certificate
active
06277902
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to rubber mixtures containing one or more soluble rubbers, hydrophobic fillers and one or more polysulfidic silanes applied on inorganic and/or organic supports, and a process for their preparation. Rubber mixtures according to the present invention are suitable for producing molded bodies of all types; in particular for producing tires and tire treads which have a low rolling resistance and a high resistance to abrasion.
BACKGROUND OF THE INVENTION
The production of silica-filled rubber mixtures, as compared with carbon black-filled rubber mixtures, requires a more protracted mixing process. The higher mixing requirement when incorporating silica, however, could, in principle, be avoided if the silica were incorporated into a rubber solution immediately after producing the rubber. The precipitated silicas currently used for producing tires, however, are not suitable for this type of process without some pretreatment since they are not precipitated when removing the solvent with steam, but largely remain in the water phase.
U.S. Pat. No. 5,166,227 describes a process for producing silica-filled emulsion rubber mixtures in which a dispersion of silica and a rubber latex are spray dried together. This process has the disadvantage that the entire amount of water has to be evaporated involving a high energy demand. In addition, the silica is not activated in contrast to the rubber mixtures in the present invention.
Polysulfidic silanes applied to supports and prepared by reacting halogenosilanes with polysulfides in the presence of a support in water are described in EP-761,742, wherein it is mentioned that these materials can also be used in the non-dried state for preparing rubber/filler master batches. It has now been found, as a new feature, that special requirements have to be placed on the fillers for preparing rubber/silica master batches which are not mentioned or suggested in EP-761,742.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that polysulfidic silanes applied to supports, can be worked up with rubber solutions and special hydrophobic oxidic and/or siliceous fillers, without any loss of filler occurring in the effluent water and that the rubber mixtures obtained in this manner exhibit better processing behavior such as e.g. more extended processing times and lower viscosities. The molded bodies prepared therefrom, surprisingly, have improved dynamic damping properties and improved abrasion behavior. Rubber mixtures according to the present invention are therefore, particularly suitable for producing tires and tire treads with a low rolling resistance and a high resistance to abrasion.
Therefore, the present invention provides rubber mixtures containing one or more soluble rubbers, 5 to 500 parts by weight of hydrophobic filler and 0.1 to 40 parts by weight of one or more polysulfidic silanes applied on inorganic and/or organic supports, wherein the parts by weight cited are each with reference to 100 parts by weight of rubber (phr).
The polysulfidic silanes applied to inorganic and/or organic supports are prepared in accordance with EP-761,742 by reacting halogenoalkylsilanes (I) and optionally organic halogenated compounds (II), with polysulfides (III) in water in the presence of an organic and/or inorganic support, with a polysulfidic silane to support weight ratio of 0.1 to 10, at temperatures of 20 to 220° C., wherein the molar ratio of components (I):(II):(III) depends on the number of bonded halogen atoms and is in the range from 1.5 to 3 moles of bonded halogen per mole of polysulfide. The polysulfidic silanes are preferably used as an aqueous suspension.
The halogenoalkylsilanes (I), organic halogenated compounds (II) and polysulfides (III) to be used correspond to the formulae
R
1
R
2
R
3
Si—X—(Hal)
n
(I)
Y—(Hal)
m
(II)
Me
2
S
x
(III)
in which
R
1
, R
2
, R
3
are identical or different and represent chlorine, a C
1
-C
18
-alkyl or C
1
-C
18
-alkoxy group, which may optionally be interrupted by oxygen, nitrogen or sulphur atoms, or a C
6
-C
12
-aryl, C
6
-C
12
-aryloxyoxy, C
7
-C
18
-alkylaryl or alkylaryloxy group, with the proviso that at least one of the groups R
1
to R
3
is an alkoxy, aryloxy or alkylaryloxy group or a chlorine atom,
X represents linear, branched or cyclic, optionally unsaturated C
1
-C
18
-alkylene groups, which may optionally be interrupted by oxygen atoms, and wherein one to three hydrogen atoms might be substituted by halogen atoms.
Y represents a monovalent to tetravalent linear, branched, optionally unsaturated or aromatic C
1
-C
36
hydrocarbon group, which may optionally be substituted with C
6
-C
12
-aryl, C
1
-C
12
-alkoxy, hydroxy, cyano, amido, C
1
-C
22
—COO or C
1
-C
22
—OOC groups, carboxylic acid or sulfonic acid groups and their salts and optionally may be interrupted by oxygen, nitrogen or sulfur atoms or may represent a mono to trivalent heteroaryl group,
m is an integer from 1 to 4,
n is an integer from 1 to 3,
x is an integer from 1 to 8,
Hal represents fluorine, chlorine or bromine and
Me represents ammonium or a metal atom.
Preferred halogenosilanes (I) are e.g. 1-chloromethyl-trimethoxysilane, 1-chloro-methyltriethoxysilane, 1-chloromethyltributoxy-silane, 1-chloromethyltri(ethoxy-ethoxy)silane, 1-chloromethylmethyl-methoxysilane, 1-chloromethylmethyl-diethoxysilane, 1-chloromethylmethoxy-dibutoxysilane, 1-chloromethyidimethyl-methoxysilane, 1-chloromethyl-dimethylethoxysilane, 1-chloromethyidimethyl-butoxysilane, 3-chloro-propyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloro-propyltripropoxysilane, 3-chloropropyltributoxysilane, 3-chloropropylpentoxysilane, 3-chloropropyltrihexoxysilane, 3-chloropropyltrioctoxysilane, 3-chloropropyltriphenoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloro-propylmethyl diethoxysilane, 3-chloropropylmethyldibutoxysilane, 3-chloropropyl-dimethylmethoxysilane, 3-chloropropyl-dimethylethoxysilane, 3-chloropropyl-diethylphenoxysilane. 1-chloro-methylmethyidiethoxysilane and 3-chloropropyl-triethoxysilane are particularly preferred.
Preferred organic halogenated compounds (II) are e.g. alkyl monohalides, such as methyl chloride, ethyl chloride, propyl chloride, butyl chloride, hexyl chloride, octyl chloride, decyl chloride, dodecyl chloride, octadecyl chloride, benzyl chloride, chloroethanol, chloropropanol, chloroacetic acid and its alkali metal salts, chloropropionic acid and its alkali metal salts, and alkylene dihalides in which Y represents methylene, ethylene, propylene, 2-hydroxypropylene, butylene, hexylene, cyclohexylene, octylene, decylene, dodecylene, 2,2-oxydiethylene, methylene-bis-oxyethylene, ethylene-bis-oxyethylene, 2,2-thiodiethylene, N-methyl-N,N-diethylene or xylidene groups. 1,2-dichloroethane, 1,6-dichlorohexane, bis-(2-chloroethyl) formal and 1,2,3-trichloropropane are particularly preferred. Organic halogenated compounds (II) may be used individually or as a mixture.
Preferred molar ratios of halogenoalkylsilanes (I) to other organic halogenated compounds (II) are between 1:0 and 1:100. Particularly preferred ratios are between 1:0 and 1:30.
Preferred polysulfides (III) are those in which Me represents ammonium, lithium, sodium or potassium.
Water is used as the reaction medium for preparing the polysulfidic silanes which are applied to an inorganic and/or organic support. In addition, mixtures of water with organic solvents may also be used such as e.g. methanol, ethanol, n-propanol, i-propanol, i-butanol, amyl alcohol, hexyl alcohol, n-octanol, i-octanol, ethylene glycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol and mixtures with aromatic, aliphatic or cycloaliphatic hydrocarbons such as e.g. toluene, cyclohexane, hexane, octane or open chain or cyclic ethers such as e.g. diethyl ether, dibutyl ether, tetrahydrofuran and 1,3-dioxolan.
Particularly suitable organic and inorganic support materials for the polysulfidic silanes applied to inorganic and/or organic supports are e.g.: Carbon blacks which have been prepared by the flame black, furnace black
Bayer Aktiengesellschaft
Cheung Noland J.
Gil Joseph C.
Niland Patrick D.
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