Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-05-21
2002-07-16
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S209000, C523S216000, C523S351000, C524S188000, C524S262000, C524S425000, C524S431000, C524S445000, C106S490000, C428S405000
Reexamination Certificate
active
06420456
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
In one of its aspects, the present invention relates to the hydrophobicizing of particles, particularly mineral particles that are hydrophilic and have surface hydroxyl groups, for example silica, silicates, clay, alumina, titanium dioxide and the like. The invention also extends, however, to treatment of non-mineral particles, for instance carbon black. In another of its aspects, the present invention also relates to the treated partices, per se. The treated particles are useful particularly, but not exclusively, as a filler in polymers, especially rubber. In another of its aspects, the present invention, also relates to a filled, particularly silica-filled, rubber masterbatch, and to a process for preparing it.
2. Description of the Prior Art
In recent years, there has developed a considerable interest in silica reinforced tires, particularly since the appearance in 1992 of the Groupe Michelin (G-M) patents (EP 05 01 227 A 1; AU-A-111 77 192) indicating that tires made with tread formulations incorporating silica enjoy some important performance advantages over those based on conventional carbon black filler. Improvements are claimed for this “Green Tire” in the areas of (a) lower rolling resistance, (b) better traction on snow, and (c) lower noise generation, when compared with conventional tires filled with carbon black.
Rubber for tires is often supplied by a rubber producer to a tire manufacturer in the form of a masterbatch containing an elastomer, which is typically a hydrocarbon rubber, an oil extender and a filler. The conventional filler has been carbon black in the form of fine particles. These particles have hydrophobic surface characteristics and will therefore disperse relatively easily within the hydrophobic elastomer. In contrast, conventional silica has a relatively hydrophilic surface, and considerable difficulty has been encountered in dispersing conventional silica in the hydrophobic rubber elastomer.
In the past, efforts have been made to make masterbatches from elastomer dispersions and aqueous dispersions of silica pigment, such as those referred to and attempted by Burke, in U.S. Pat. No. 3,700,690. Burke attempted to overcome the previously known difficulties of incorporating fine particles of silica uniformly into a masterbatch. At the time of the Burke invention, there was no known elastomer-silica masterbatch offered in the commercial market. Similarly today, to the Applicant's knowledge, there are no commercially available in situ produced elastomer-silica masterbatches in the market, despite the efforts of Burke (i.e., conventional elastomer-silica masterbatches are produced and available in the dry state).
SUMMARY OF THE INVENTION
It is an object of the present invention to obviate or mitigate at least one of the above-mentioned disadvantages of the prior art.
It is another object of the present invention to provide a novel, relatively hydrophobic particulate material.
It is yet another object of the present invention to provide a novel process for treating particulate material to render it relatively hydrophobic.
It is yet another object of the present invention to provide a novel masterbatch composition comprising an elastomer and a relatively hydrophobic particulate material.
It is yet another object of the present invention to provide a novel process for producing a masterbatch composition comprising an elastomer and a relatively hydrophobic particulate material.
Accordingly, in one of its aspects, the present invention provides a process for treating particles, particularly mineral particles, to render them hydrophobic, the process comprising the steps of:
(a) contacting the particles with a compound of Formula I:
or an acid addition or quaternary ammonium salt thereof, in which:
at least one of R
1
, R
2
and R
3
, preferably two of R
1
, R
2
and R
3
and most preferably R
1
, R
2
and R
3
are hydroxyl or hydrolysable groups;
R
4
is a divalent group that is resistant to hydrolysis at the Si—R
4
bond;
R
5
is selected from the group comprising: hydrogen; C
1-40
alkyl; a C
2-40
mono-, di- or tri-unsaturated alkenyl group; a C
6
-C
40
aryl group; a group of the formula:
in which x is an integer from 2 to 10, R
13
and R
14
, which may be the same or different, are each hydrogen; C
1-18
alkyl; C
2-18
mono-, di- or tri-unsaturated alkenyl; phenyl; a group of formula:
wherein b is an integer from 1 to 10; a group of formula:
wherein c is an integer from 1 to 10 and R
22
and R
23
which may be the same or different, are each hydrogen, C
1-10
alkyl group or C
2-10
alkenyl group, provided that there is no double bond in the position alpha to the nitrogen atom; a group of formula:
—[(CH
2
)
r
NH]
d
—H
wherein r is an integer from 1 to 6 and d is an integer from 1 to 4;
R
6
may be any of the groups defined for R
5
, or R
5
and R
6
may together form a divalent group of formula:
in which A is selected from the group comprising —CHR or —NR group in which R is hydrogen or a C
1-40
alkyl or C
2-40
alkenyl group, a C
6
-C
40
aryl group, an oxygen atom and a sulfur atom, and t and v are each independently 1, 2, 3 or 4; provided that the sum of t and v does not exceed 6, and is preferably 4; and
(b) contacting the particles with a compound of the Formula II:
in which:
R
15
, R
16
and R
17
have the same definitions as R
1
, R
2
and R
3
; and
R
12
is selected from the group comprising a C
8-40
alkyl group or a C
8-40
mono-, di- or tri-unsaturated alkenyl group, either of which can be interrupted by one or more aryl groups, preferably phenyl groups; a group of formula:
or an acid addition or quaternary ammonium salt thereof in which R
18
is a divalent group resistant to hydrolysis at the Si—R
18
bond, R
19
is selected from the group comprising hydrogen, a C
1-40
alkyl group, a C
2-40
mono-, di- or tri-unsaturated alkenyl group, a substituted aromatic group, for example the phenylene group —(C
6
H
4
)—, the biphenylene group —(C
6
H
4
)—(C
6
H
4
)—, the —(C
6
H
4
)—O—(C
6
H
4
)— group or the naphthylene group, —(C
10
H
6
)—, the aromatic group being unsubstitued or substituted by a C
1-20
alkyl or C
2-20
mono-, di- or tri-unsaturated alkenyl group; and R
20
may be any of the groups defined for R
19
, with the provisos that R
19
and R
20
do not have a tertiary carbon atom adjacent to the nitrogen atom and that at least one of R
19
and R
20
has a carbon chain at least 8 carbon atoms in length uninterrupted by any heteroatoms.
Preferably, R
18
is a C
1
-C
40
saturated or unsaturated group (e.g., alkenyl, aryl, cycloalkyl and the like).
In the present process, Steps (a) and (b) may be conducted concurrently or sequentially. If Steps (a) and (b) are conducted sequentially, it is preferred to conduct Step (a) followed by Step (b).
As will be apparent to those of skill in the art, there are instances where Formulae I and II may be the same compound—e.g., when R
5
=R
19
=a C
8-40
alkyl group or R
5
=R
19
=a C
8-40
mono-, di- or tri-unsaturated alkenyl group. Thus, in such cases where Formulae I and II are the same compound, it will be clearly understood that the present process intentionally embodies a single step process (i.e., where the compound of Formulae I and II is added in a single step) and a multi-step process (i.e., where the compound of Formulae I and II is added proportionally in two or more steps).
In another of its aspects, the present invention provides a treated particulate material comprising particles having bound thereto an aminohydrocarbonsiloxane (e.g., an amino(alkyl)siloxane) moiety—i.e., a hydrocarbon moiety comprising both silicon and nitrogen.
Preferably, the aminohydrocarbonsilane moiety has the formula
in which:
R
a
, R
b
and R
c
are the same or different and each is selected from —O— and —C
p
H
2p
—, optionally substituted by one or more oxygen atoms and wherein p is an integer of from 1 to 10; and
R
12
is a C
8-40
alkyl group; a C
8-40
mono-, di
Bayer Inc.
Cheung Noland J.
Gil Joseph C.
Szekely Peter
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