Diacetylenic polyorganosiloxanes, intermediates therefor,...

Details Diacetylenic polyorganosiloxanes, intermediates therefor,... Diacetylenic polyorganosiloxanes, intermediates therefor,...

2000-04-19

2001-08-07

Dawson, Robert (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Compositions to be polymerized by wave energy wherein said...

C526S285000, C526S279000, C568S673000, C556S445000, C556S479000, C528S031000, C528S025000, C528S029000, C528S012000, C528S015000, C570S189000, C525S479000

Reexamination Certificate

active

06271280

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to acetylenic polyorganosiloxane compounds. More particularly, it relates to a class of diacetylenic polyorganosiloxanes and their curing.
Polyorganosiloxanes (hereinafter sometimes designated “silicones”) having acetylenic moieties are known in the art, being disclosed in a number of publications. For example, compounds having conjugated diacetylenic groups bound directly to silicon atoms are disclosed in Son et al.,
Macromolecules,
28, 399-400 (1995), and in Parnell et al.,
J. Poly. Sci., Poly. Chem. Ed.,
11, 1107-1110 (1973). Genera of compounds in which similar diacetylenic groups are present in combination with amide or ester groups and silicone moieties are among the subjects of European patent application 210,056 and Lai et al.,
Mol. Cryst. Liq. Cryst.,
188, 25-39 (1990). Silicones having pendant phenyldiethynylphenyloxyalkyl groups are disclosed in Hsu et al.,
Poly. Prep.,
33, 214-215 (1992). Diacetylenic silicones containing a Si—O—C linkage are disclosed in German published applications 4,302,993 and 4,303,080.
Such materials have potential for being cured, as by heat or radiation, to produce materials useful, for example, as release coatings or conformal coatings. However, they suffer from various disadvantages including high cost of preparation and chemical instability, the latter being particularly true of compounds having a Si—O—C linkage.
French patent applications 96/11,999 and 96/12,000 disclose polymeric compositions containing ether groups in combination with diacetylenic moieties. However, no silicone moieties are present.
It remains of interest, therefore, to develop diacetylenic silicone compounds which are relatively inexpensive, stable and easily cured.
SUMMARY OF THE INVENTION
The present invention provides a series of chemically stable diacetylenic silicones and a series of acetylenic silicone intermediates therefor, said intermediates being readily converted to the diacetylenic compounds by a coupling reaction. Also provided are cured compositions prepared from said diacetylenic silicones, as well as a method of curing the same which employs ultraviolet radiation but does not require the presence of promoters, sensitizers or other additives.
In the formulas herein, a conventional nomenclature for polyorganosiloxanes is employed. It utilizes the symbols M, D, T and Q for radicals of the general type R
3
SiO
1/2
, R
2
SiO
2/2
, RSiO
3/2
and SiO
4/2
as abbreviations for “mono”, “di”, “tri” and “quaternary”, respectively, to represent the number of Si—O moieties in which the oxygen atom is linked to another silicon atom, the fractional subscripts designating oxygen atoms bound to two silicon atoms each. Thus, as used herein the symbols D and T do not have their common meanings of deuterium and tritium, respectively.
In one of its aspects, then, the present invention includes intermediate compositions comprising ethynylorgano polyorganosiloxanes having the formula
(M
1
)
a
(M
2
)
b
(D
1
)
c
(D
2
)
d
(T
1
)
e
(T
2
)
f
Q
g
,  (I)
wherein:
each of “a”, “b”, “c”, “d”, “e”, “f” and “g” is 0 or greater, with the proviso that “b”+“d”+“f” is at least 1;
each R
1
is independently a divalent organic radical having no Si—O—C moieties and containing at least one oxygen atom not directly bound to Si or at least one CH═CH moiety directly bound to Si; and
each R
2
is independently an alkyl radical, alkoxy radical, alkenyl radical, aryl radical, aryloxy radical, alkyl-substituted aryl radical, and aralkyl radical which groups may be halogenated.
Another aspect of the present invention includes compositions comprising poly(conjugated diacetylenic)polyorganosiloxanes formed by coupling of the above-described ethynylorgano polyorganosiloxanes.
A further aspect of the present invention is a method for producing a cured polyorganosiloxane which comprises exposing said poly(conjugated diacetylenic)polyorganosiloxane compositions to heat or radiation. A still further aspect is cured polyorganosiloxanes so prepared.
DETAILED DESCRIPTION
In the ethynylorgano silicones of formula I, the “a”−“g” subscripts are each 0 or greater with the proviso that “b”+“d”+“f” is at least 1. Preferably, “c” is in a range between about 1 and about 500 and “e”, “f” and “g” are each 0; i.e., the preferred silicones are triorganosiloxy-terminated polyorganosiloxanes. More preferably, “c” is in a range between about 5 and about 50; most preferably, in a range between about 5 and about 25.
The sum “b”+“d”+“f”, i.e., the total number of ethynyl groups per molecule, is at least 1, i.e. mono, preferably at least 2, and more preferably 2. In the most preferred ethynylorgano silicones, “b” is 2 and “d” and “f” are each 0; i.e., the preferred compounds are ethynyl-terminated polyorganosiloxanes.
A particularly preferred class of ethynyl-terminated silicones consists of those having the formula
wherein “n” is in a range between about 1 and about 500, preferably in a range between about 5 and about 50 and most preferably in a range between about 5 and about 25; “p” is in a range between about 1 and about 100, preferably in a range between about 1 and about 10, and most preferably 1 or 2; R
1
is as previously defined; and R
2
is independently at each occurrence a C
1-22
alkyl, C
1-22
alkoxy, C
2-22
alkenyl, C
6-20
aryl, C
6-20
aryloxy, C
6-22
alkyl-substituted aryl, and C
6-22
aralkyl groups may be halogenated, for example, flourinated to contain fluorocarbons such as C
1-22
fluoroalkyl; Z, independently at each occurrence, represents the molecular hook; and X, independently at each occurrence, represents the linker. The term “alkyl” as used in various embodiments of the present invention is intended to designate both normal alkyl, branched alkyl, aralkyl, and cycloalkyl radicals. Normal and branched alkyl radicals are preferably those containing from 1 to about 12 carbon atoms, and include as illustrative non-limiting examples methyl, ethyl, propyl, isopropyl, butyl, tertiary-butyl, pentyl, neopentyl, and hexyl. Cycloalkyl radicals represented are preferably those containing from 4 to about 12 ring carbon atoms. Some illustrative non-limiting examples of these cycloalkyl radicals include cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, and cycloheptyl. Preferred aralkyl radicals are those containing from 7 to about 14 carbon atoms; these include, but are not limited to, benzyl, phenylbutyl, phenylpropyl, and phenylethyl. Aryl radicals used in the various embodiments of the present invention are preferably those containing from 6 to 14 ring carbon atoms. Some illustrative non-limiting examples of these aryl radicals include phenyl, biphenyl, and naphthyl. An illustrative non-limiting example of a halogenated moiety suitable for R
2
groups is trifluoropropyl. Most often, all R
2
radicals are methyl.
The R
1
radicals in formulas I and II are divalent radicals which contain no Si—O—C moieties, which detract from stability. In one preferred embodiment of the invention, said R
1
radicals contain at least one oxygen atom not directly bound to Si. Such R
1
radicals most often have the formula III or IV
wherein each R
3
is independently hydrogen or C
1-4
alkyl, “m” is in a range between about 0 and about 100, “y” is in a range between about 3 and about 10 and (CH
2
)
y
is bonded to silicon. Most often, each R
3
is hydrogen, “m” is 1 and “y” is 3.
Formula (IV)
wherein “y” is defined above, (CH
2
)
y
is bonded to silicon, “x” is in a range between about 1 and about 100, preferably in a range between about 1 and about 50 and most preferably, in a range between about 1 and about 10.
In another preferred embodiment, R
1
contains at least one olefinic moiety directly bound to Si, and more preferably, only one olefinic moiety directly bound to Si. Radicals of this type include those of the formulas
—R
4
—CH═CH—  (V)
and
—CH═CH—R
4
—CH═CH—  (VI)
wherein R
4
is a divalent organic radical, which may be an aliphatic, aromatic or mixed aliphatic-aromati

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