Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1998-10-01
2002-01-01
Mullis, Jeffrey (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S256000, C525S259000, C525S303000
Reexamination Certificate
active
06335401
ABSTRACT:
The present invention relates to the radical polymerization of monomers which can be polymerized by this route in the presence of a stable radical and of a macroinitiator containing reactive side functions, in order to synthesize grafted copolymers with control over the number of grafts and the length of these grafts.
European patent application EP-A-0,135,280 describes the synthesis of grafted polymers. However, the routes recommended always involve stripping a proton from a polymer chain by means of a free radical. This technique does not make it possible effectively to control the number of radicals created, and thus the number of grafts on the polymer chain.
The Applicant Company has conducted research into a technique capable of leading to more and shorter grafts than the known technique, which leads to fewer, longer grafts. The novelty of the invention consists, as indicated above, in using a macroinitiator containing peroxide side functions in a radical polymerization in the presence of stable radicals, in order to synthesize grafted copolymers with two main controls. The first regards the introduction of the peroxide side groups, onto which the number of reactive functions can be formed quantitatively, which makes it possible to select the number of grafts on the polymer trunk in order to obtain more or less dense grafting. The second control regards the architecture of these grafts. By virtue of the presence of stable radicals (of nitroxyl type), the mass distribution of the grafts is very well controlled and they can be considered to be of virtually identical length; the stable radicals make it possible to have polydispersity indices generally of less than 1.5. This characteristic gives new properties to the copolymers obtained, which are novel. Furthermore, by means of this control of the chain ends, the synthesis of copolymers grafted with grafts of block copolymer type can be envisaged and achieved. This structure gives properties that are again different to those of the known grafted copolymers.
The system proposed thus provides control of the polymerization, which is effected both on the graft length—the lengths of the grafts being more or less identical—and on the chain ends—which makes it possible to form block copolymers on the grafts.
The subject of the present invention is thus, firstly, a grafted copolymer formed of a (co)polymer trunk bearing grafts of formula (I):
—O—PM
1
—(PM
2
)—T (I)
in which:
PM
1
represents a polymer block derived from at least one monomer M
1
which can be (co)polymerized via a radical route;
PM
2
, which is optionally present, represents a polymer block derived from at least one monomer M
2
which can be (co)polymerized via a radical route; and
T represents the residue of a stable radical T
•
.
The monomers M
1
and M
2
are chosen in particular from vinyl, allylic, vinylidene, diene and olefinic monomers.
The term vinyl monomers is understood to refer to (meth)acrylates. vinyl aromatic monomers, vinyl esters, vinyl ethers, (meth)acrylonitrile, (meth)acrylamide and mono- and di(C
1
-C
18
alkyl)(meth)acrylamides, and monoesters and diesters of maleic anhydride and of maleic acid.
The (meth)acrylates are, in particular, those of the respective formulae:
in which R
0
is chosen from linear or branched, primary, secondary or tertiary C
1
-C
18
alkyl radicals, C
5
-C
18
cycloalkyl radicals, (C
1
-C
18
) alkoxy (C
1
-C
18
) alkyl radicals, (C
1
-C
18
)alkylthio (C
1
-C
18
)alkyl radicals, aryl radicals and arylalkyl radicals, these radicals optionally being substituted with at least one halogen atom and/or at least one hydroxyl group after protection of this hydroxyl group, the alkyl groups above being linear or branched; and glycidyl, norbornyl and isobornyl (meth)acrylates.
As examples of useful methacrylates, mention may be made of methyl, ethyl, 2,2,2-trifluoroethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-amyl, isoamyl, n-hexyl, 2-ethylhexyl, cyclohexyl, octyl, isooctyl, nonyl, decyl, lauryl, stearyl, phenyl, benzyl, &bgr;-hydroxyethyl, isobornyl, hydroxypropyl and hydroxybutyl methacrylates.
As examples of acrylates of the above formula, mention may be made of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, hexyl, 2-ethylhexyl, isooctyl, 3,3,5-trimethylhexyl, nonyl, isodecyl, lauryl, octadecyl, cyclohexyl, phenyl, methoxymethyl, methoxyethyl, ethoxymethyl and ethoxyethyl acrylates.
For the purposes of the present invention, the term vinyl aromatic monomer is understood to refer to an aromatic monomer containing ethylenic unsaturation, such as styrene, vinyltoluene, &agr;-methylstyrene, 4-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, 4-ethylstyrene, 4-ethoxystyrene, 3,4-dimethylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chloro-3-methylstyrene, 3-tert-butylstyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene and 1-vinylnaphthalene.
As vinyl esters, mention may be made of vinyl acetate, vinyl propionate, vinyl chloride and vinyl fluoride, and, as vinyl ethers, mention may be made of vinyl methyl ether and vinyl ethyl ether.
As vinylidene monomer, mention is made of vinylidene fluoride.
The term diene monomer is understood to refer to a diene chosen from linear or cyclic, conjugated or non-conjugated dienes such as, for example, butadiene, 2,3-dimethylbutadiene, isoprene, 1,3-pentadiene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,9-decadiene, 5-methylene-2-norbornene, 5-vinyl-2-norbornene, 2-alkyl-2,5-norbornadienes, 5-ethylene-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(5-hexenyl)-2-norbornene, 1,5-cyclooctadiene, bicyclo[2,2,2]octa-2,5-diene, cyclopentadiene, 4,7,8,9-tetrahydroindene and isopropylidene tetrahydroindene.
As olefinic monomers, mention may be made of ethylene, butene, hexene and 1-octene. Fluoroolefinic monomers may also be mentioned.
The present invention involves a stable free radical. A stable free radical should not beconfused with free radicals which have a fleeting lifetime (a few milliseconds), such as the free radicals derived from the usual polymerization initiators, for instance peroxides, hydroperoxides and azo-type initiators. Free radicals which initiate polymerization tend to accelerate the polymerization. In contrast, stable free radicals generally tend to slow the polymerization down. It can generally be stated that a free radical is stable, for the purposes of the present invention, if it is not a polymerization initiator and if, under the working conditions of the present invention, the average lifetime of the radical is at least 5 minutes. During this average lifetime, the molecules of the stable free radical permanently alternate between the state of a radical and the state of a group linked to a polymer chain via a covalent bond derived from a coupling reaction between a radical centred on an oxygen atom and a radical centred on a carbon atom. Needless to say, it is preferable for the stable free radical to have good stability throughout its use in the context of the present invention. Generally, a stable free radical can be isolated in radical form at room temperature.
The family of stable free radicals includes compounds which act as radical polymerization inhibitors, stable nitroxide radicals, i.e. species comprising the group ═N—O
•
.
Thus, the residue T is that represented by formula (IIa) or (IIb):
derived from the stable radicals (IIIa) and (IIIb) respectively:
in which:
R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
, which may be identical or different, each represent:
a halogen atom, such as chlorine, bromine or iodine;
a linear, branched or cyclic, saturated or unsaturated hydrocarbon-based group, such as an alkyl or phenyl radical;
an ester group —COOR
9
or an alkoxy group —OR
10
or a phosphonate group —PO(OR
11
)
2
in which R
9
, R
10
and R
11
each independently represent a linear, branched or cyclic, saturated or unsaturated hydrocarbon-based group;
a polymer chain which can be, for example, a poly(methyl methacrylate) chain, a polybutadiene chain, a polyolefin chain
Bertin Denis
Boutevin Bernard
Robin Jean-Jacques
Atofina
Mullis Jeffrey
LandOfFree
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