Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2001-05-03
2003-07-08
Berman, Susan W. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S067000, C522S099000, C522S148000, C522S170000, C528S013000, C528S026000, C528S033000, C528S040000, C430S280100, C430S286100
Reexamination Certificate
active
06590009
ABSTRACT:
This application is an application under 35 U.S.C. Section 371 of International Application Number PCT/FR99/01911 filed on Aug. 2, 1999.
The field of the invention is that of the initiating of the polymerization and/or crosslinking reactions of monomers, oligomers and/or polymers comprising reactive functional radicals capable of forming intrachain and interchain bridgings, so as to obtain a polymerized and/or crosslinked coating or composite material having a certain hardness and a certain mechanical strength.
More specifically, a subject matter of the present invention is a novel process for polymerization and/or crosslinking in the presence of novel initiators, which can be activated under an electron beam and/or gamma radiation, comprising at least one boron derivative which make possible the initiation and the progression of reactions for the formations of polymers and/or resins from substrates formed of monomers, oligomers and/or of polymers with reactive organofunctional groups.
The reactions more particularly concerned are those in which agents act as direct promoters of interchain and/or intrachain bonds. In the present case, these reactions are initiated with activation by an electron beam or by gamma radiation.
In the present description, the polymers and/or resins obtained are prepared from monomers, oligomers and/or polymers which are either (1) of organic nature, in particular solely of hydrocarbonaceous nature, or (2) of polyorganosiloxane nature and which comprise, in their structure, organofunctional groups, for example of epoxide, oxetane and/or alkenyl ether type, which react after activation by an electron beam and/or gamma radiation of the initiators according to the invention described below. In addition, it is also possible to use (3) monomers, oligomers and/or polymers with acrylic groups and/or methacrylic groups, which can be added to the polymerization medium comprising entities (1) and/or (2).
Another subject matter of the present invention is compositions comprising the polymerizable and/or crosslinkable base materials (monomers, oligomers and/or polymers), preferably of polyorganosiloxane nature, the initiators described below and, optionally, one or more additives chosen from those generally known in the applications for which these compositions are intended.
For example, these compositions can be used for the preparation of coatings on items such as solid articles or substrates, in particular a paper substrate, a fabric, a polymer film of polyester or polyolefin type, an aluminum substrate and/or a tinplate substrate.
Initiators for polymerizing and/or crosslinking monomers, oligomers and/or polymers comprising reactive organofunctional groups in their structures are disclosed in EP-0 562 897. The initiating salts of this patent represent a significant technical advance in comparison with the previously known initiators of onium salt or organometallic complex type and in particular in comparison with those in which the anion of the initiating salt is SbF
6
−
, which is one of the only ones which is correct with regard to performance, but which presents serious operating problems because of the presence of heavy metals.
To assess the performances of initiators which can be activated under an electron beam and/or gamma radiation, their ability to polymerize a polymer or matrix is evaluated via tests, such as that of touch, or trade tests, such as that of the peel strength for nonstick coatings.
One of the essential objectives of the present invention is the development of a novel process which makes possible the polymerization and/or crosslinking of a matrix based on monomers, oligomers and/or polymers in the presence of novel initiators which can be activated by an electron beam and/or gamma radiation.
It should be noted that the initiators of this novel process have a markedly improved reactivity, in particular in comparison with those comprising an iodonium cation and/or antimony-derived anion within their structure. In addition, the use of these novel initiators does not necessarily require inert atmosphere conditions and, furthermore, they prove to be much less toxic.
An essential objective of the invention is to provide a high-performance process with respect to the greatest number of organofunctional monomers, oligomers and/or polymers which can be polymerized and/or crosslinked under activation with an electron beam and/or gamma radiation, the monomers, oligomers and/or polymers being in particular (1) of organic nature, preferably solely of hydrocarbonaceous nature, or (2) of polyorganosiloxane nature, optionally as a mixture (3) with other monomers, oligomers and/or polymers comprising acrylic and/or methacrylic groups.
Another essential objective of the invention is to provide a process which uses efficient initiators at a low concentration and which only requires small amounts of energy (expressed in kilograys) for carrying out the polymerization and/or crosslinking. For this reason, the industrial processes using initiators of these types prove to be particularly economical.
Another essential objective of the invention is to provide a high performance process in which the polymerization and/or crosslinking reactions are carried out at high rates. Thus, the duration of activation under an electron beam and/or gamma radiation is very short and is generally approximately less than one second and of the order of a few tenths of a second for the preparation of very thin coatings. Of course, the polymerisation/crosslinking time may vary according to the number of electron beam and/or gamma radiation sources, the duration of the activation and the distance between the composition and the activating beam(s). Thus, the process according to the invention can be employed with industrial devices in which the rate of forward progression of the composition to be crosslinked on a backing strip is very high.
Another objective of the invention is to provide compositions comprising organofunctional monomers, oligomers and/or polymers which can be crosslinked via initiators which can be activated by an electron beam and/or gamma radiation. The optimum performances are obtained in particular with compositions comprising organofunctional monomers, oligomers and/or polymers of polyorganosiloxane nature.
Another objective of the invention is to provide compositions of this type which can be used just as easily in a thin layer, the thickness of which lies, for example, in the range from 0.1 to 10 &mgr;m, as in a thicker layer, the thickness of which lies, for example, in the range from a value of greater than 10 micrometers to several centimeters.
Another objective of the invention is to provide compositions of this type for the preparation of composite materials.
These various objectives are achieved by the invention, which relates first of all, in its first subject matter, to a novel process for crosslinking and/or polymerizing, under an electron beam and/or gamma radiation, compositions based on monomers, oligomers and/or polymers comprising organofunctional groups, in which process the crosslinking and/or polymerization is carried out in the presence of an initiator which can be activated by an electron beam and/or gamma radiation comprising a boron derivative of formula M
+
B(Ar)
4
−
(I) where:
M
+
, an entity carrying a positive charge, is chosen from an alkali metal from columns IA and IIA of the Periodic Classification (CAS version),
Ar is an aromatic derivative, optionally substituted by at least one substituent chosen from a fluorine radical, a chlorine radical or a linear or branched alkyl chain, which can itself be substituted by at least one electron-withdrawing group, such as C
n
F
2n+1
, with n being between 1 and 18 (for example: CF
3
, C
3
F
7
, C
2
F
5
or C
8
F
17
), F and OCF
3
.
According to an alternative form of the invention, M is chosen from lithium, sodium, cesium and/or potassium.
By way of example, the boron derivative of the initiator according to the invention is of formula:
LiB(C
6
F
5
)
4
, KB(C
6
Berman Susan W.
Rhodia Chimie
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