Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-09-07
2004-02-10
Robertson, Jeffrey B. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S492000, C524S588000, C528S021000, C528S025000, C528S030000, C556S427000
Reexamination Certificate
active
06689834
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to sulfur-containing oligosiloxanes which are liquid at −25-100° C., processes for their preparation and their use in silica-containing rubber mixtures which can be crosslinked with sulfur.
BACKGROUND OF THE INVENTION
Mixtures in which polymers are compounded with reinforcing silicas and sulfur-containing silanes have frequently been proposed for the preparation of rubber mixtures which are crosslinked with sulfur and have a low loss factor in mechanical damping.
Tires of low rolling resistance are those that can be produced with such low-damping rubbers. The particular requirements here during preparation of the mixture (viscosity level), the rubber properties additionally necessary, such as abrasion and wet skidding resistance, and the desired crosslinking properties (scorch resistance) impose considerable demands both on the polymers and on the fillers and the crosslinking system.
The preparation and use of sulfur-containing alkylsilanes is prior art, cf. U.S. Pat. No. 4,100,172, DD-A5-299 187, DE-A1-2 856 229, EP-A1-466 066 and EP-A1-731 824.
DE-A-28 37 117 describes the combination of sulfide-containing silanes and/or mercapto- or alkenylalkoxysilanes in silica-containing rubber mixtures as advantageous for increasing the stability to hot air, in particular of EPDM. DE-A 29 33 247 describes the use of siloxanes with SiOH or SiOR groups in rubber mixtures with silica.
U.S. Pat. No. 4, 474,908 describes the combination of a crosslinking-active with a crosslinking-inactive methylalkoxysilane in order to improve the viscosity and scorch of rubber mixtures.
JP-B-62 48 116 describes rubber mixtures of polymer, carbon black and silicas treated with methylhydrogenosiloxanes and sulfur-containing silanes.
EP-A2-761 748 describes the improvement in the viscosity properties of silica-containing mixtures by admixing siloxanes with hydrogen atoms and alkoxy- and acyloxy groups and optionally, sulfur-containing silanes. The chain lengths of the silanes here is at a degree of polymerization of approx. 40. The ratio of alkenyl- or hydrogeno-siloxane radicals to methylalkoxysiloxane radicals is between 10:90 to 21:79. EP-A2-784 072 also describes mixtures of siloxanes and sulfur-containing silanes in order to lower the viscosity of the mixture.
WO 96/16125 and WO 99/02580 also describe functionalized polyorgano-siloxanes and their production and their use in rubber mixtures, it being possible for the siloxane chains to have a length of up to 300 siloxy units. Furthermore, sulfur-functional polyorganosiloxanes, their production and rubber mixtures containing the same are described in EP-A2 964021 and EP-A2 997489.
Thus, It is known to employ mixtures of siloxanes and sulfur-containing silanes. This has the following disadvantages: first, the substances must be blended very accurately by the customer by a mixing step, and next, large amounts of undesirable alcohols are released during processing due to the alkoxy and acyloxy radicals of the siloxanes, which is ecologically unacceptable.
Furthermore, it is known to produce sulfur-containing oligosiloxanes. This does, however, have the following disadvantages: the direct production from alkenyl oligosiloxanes and sulfur by the known sulfurization processes results in highly viscous and/or gelled products. Other processes are considerably more complicated.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a mixture of alkoxysiloxane and sulfur donors which is easy to meter, can be mixed homogeneously and at least, in part, does not have the disadvantages of the prior art.
This object is achieved according to the present invention by sulfur-containing siloxanes of the general formula (I)
wherein
R and R″ independently of one another represent a C
1
-C
24
-alkyl radical or a C
6
-C
24
-aryl radical,
R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C
4
-C
24
-alkyl radical or a sulfur-containing dicyclopentyl radical,
R′″ represents R, OR or H, wherein the radicals R and R′″ can be identical or different,
R
IV
represents R, SiR
3
′″ or H, wherein the radicals R, R′″ and R
IV
can be identical or different,
the sum of x and y is a number in the range from 2 to 200, with the proviso that always only one radical R′ is present per siloxane molecule.
DETAILED DESCRIPTION OF THE INVENTION
“Sulfur-containing” means that the corresponding radicals have been formed by reaction of a double bond with sulfur and/or hydrogen sulfide. The sulfur-containing radicals, thus, carry —SH, Sx or other sulfur substituents. These can, optionally, also be coordinated associatively on the double bond. Sx here denotes sulfur chains or rings with a length in the range of 1-100 sulfur atoms.
If R′ represents a sulfur-containing C
4
-C
24
-alkyl radical, the C
4
-C
24
-alkyl represents e.g. a butane, pentane, hexane, heptane, octane or nonane radical, preferably a butane, hexane or octane.
R and R″ represent a C
1
-C
24
-alkyl radical, which can be present in a linear, branched or also a cyclic structure, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl or tert-butyl radicals. For R and R″, methyl, ethyl, propyl, cyclopentyl, cyclohexyl and tert-butyl radicals are preferred, more preferably methyl, ethyl, cyclohexyl and tert-butyl radicals. The alkyl radicals can also be halogen-substituted, and Cl-methyl and Cl-propyl radicals are preferred.
R and R″ can also represent a C
6
-C
24
-aryl radical, which can be substituted in its turn by the above-mentioned C
1
-C
24
-alkyl radicals or other aryl radicals, such as the phenyl, cyclopentadienyl, naphthyl, methyl-phenyl, ethylphenyl or tert-butylphenyl radical. Phenyl radicals are preferred.
The above-mentioned alkyl radicals can, of course, in their turn also be substituted again by aryl radicals, such as phenylmethyl, phenylethyl or also triphenylmethyl radicals.
The sum of x and y is a number in the range from 2 to 200, preferably 2 to 50, more preferably 2 to 20, and most preferably 2 to 10.
The x elements of the structure [RR′SiO] and the y elements of the structure [OR″R′″SiO] can, of course, each be arranged as blocks along the siloxane chain in a sequential fashion or regularly or in random distribution.
If R
IV
=H or OR, cyclic condensates can be formed. If R
IV
=H at both chain ends, such condensates are formed spontaneously in the mixture with the elimination of water. If at one chain end, R
IV
=H and at the other chain end, R
IV
=OR, such condensates are formed spontaneously in the mixture with the elimination of the alcohol ROH. If R
IV
=OR at both chain ends, such condensates are formed in the mixture in the presence of catalysts and/or water, e.g. atmospheric moisture, with the elimination of the alcohol ROH.
The problem is also solved according to the present invention by sulfur-containing siloxanes (Ia) which are composed of the following structural units (K), (L), (M) and (N)
wherein
R
VI
represents a C
1
-C
24
-alkyl radical, a C
6
-C
24
-aryl radical, a C
1
-C
24
-alkoxy radical, a C
6
-C
24
-aryloxy radical, H or OH,
R′ has the abovementioned meaning,
R
VII
, R
VIII
, R
IX
, R
X
, R
XI
and R
XII
independently of one another represent a C
1
-C
24
-alkyl radical, a C
6
-C
24
-aryl radical or H,
the above-mentioned restrictions apply to x and y and
w and z each independently of one another can be an integer between 0 and 100. The individual structural units can be arranged in succession in any desired order and linearly or cyclically. If a linear chain is present, terminal chain groups R
IV
and OR
IV
can additionally be present, wherein R
IV
has the abovementioned meaning.
The sulfur-containing siloxanes of the structure (I) according to
Ackermann Jürgen
Grabowski Stefan
Weidenhaupt Hermann-Josef
Bayer Aktiengesellschaft
Gil Joseph C.
Robertson Jeffrey B.
Seng Jennifer R.
LandOfFree
Liquid sulfur-containing oligosiloxanes and their use in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid sulfur-containing oligosiloxanes and their use in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid sulfur-containing oligosiloxanes and their use in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3303742