Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
1999-07-19
2002-04-09
Woodward, Ana (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S028000, C528S030000, C528S033000, C528S038000, C528S043000, C525S126000, C525S127000, C525S128000, C525S131000
Reexamination Certificate
active
06369186
ABSTRACT:
This application is an application under 35 U.S.C. Section 371 of International Application Number PCT/FR97/01979, filed on Nov. 5, 1997.
The subject-matter of the present invention is novel crosslinkable compositions for forming novel polyurethane films comprising functionalized silicone oils and the use of the novel polyurethane films as protective coating, in particular for car bodies, boat hulls, the bodies of household goods and appliances, or any other surface.
Protective coatings have to possess numerous qualities combining both aesthetic and visual appearances and properties of resistance to external influences. A first fundamental criterion of effectiveness for protective coatings is the ability to withstand acids, in particular in the case of car paints or varnishes; the latter have to withstand the action of acid rain. A second fundamental criterion of effectiveness relates to the hydrophobic qualities, which, of course, must be high. A third fundamental criterion is the resistance to mechanical stresses, such as the resistance to scratching.
Numerous coating or paint compositions comprising silicone oils have been provided. The compositions of U.S. Pat. No. 5,268,215 or those of Patent EP 531,463 should in particular be noted; however, these do not exhibit all the qualities required which make it possible to obtain stable protection which is lasting over time. In addition, these compositions sometimes have to be used in a rigorous and complex way for an application which does not guarantee minimum effectiveness.
The object of the present invention is to provide novel crosslinkable compositions in order to form polyurethane films. These novel crosslinkable compositions, which comprise functionalized silicone oils, have qualities, evaluated according to the criteria above, which are improved with respect to the known compositions of the prior art. In addition, the novel crosslinkable compositions are relatively quick to prepare and are easy to use.
A marked improvement in quality and stability of the properties of resistance to acids, of the properties of resistance to mechanical stresses, such as the resistance to cracking, and of the hydrophobic properties is observed for the novel polyurethane films resulting from the crosslinkable compositions of the invention.
The novel crosslinkable compositions according to the invention comprise:
(a) 20 to 50 weight % of polyisocyanate,
(b) 50 to 80 weight % of acrylic oligomer comprising hydroxyl groups, the content by weight of which with respect to the acrylic oligomer is between 2.5 and 4.5%,
(c) 1 to 10 weight % of a silicone oil of formula (I):
in which:
(1) o and p are identical or different integers of between 1 and 100 and preferably from 1 to 50,
(2) 1 represents an integer such that 1=2+q,
(3) q represents an integer of between 0 and 10,
(4) m represents an integer of between 1 and 60, preferably between 1 and 30, particularly preferably from 1 to 10,
(5) n is an integer such that 20<(100×m)/(m+n)<60, preferably 25<(100×m)/(m+n)<55,
(6) the symbols R
1
and R
2
are identical and/or different and represent a hydrocarbon-comprising radical chosen from linear or branched alkyl radicals having from 1 to 4 carbon atoms, linear or branched alkoxy radicals having from 1 to 4 carbon atoms, aryl radicals or alkylaryl radicals and preferably a methyl radical, a phenyl radical, a methoxy radical or an ethoxy radical,
(7) the symbols R
3
and R
4
are identical and/or different and are chosen from:
monovalent —(CH
2
)
h
—Si—(R
1
)
3
radicals where h is between 1 and 10, preferably from 1 to 3,
monovalent aromatic alkylaryl radicals, the linear or branched alkyl part comprising 1 to 4 carbon atoms, the symbol R
3
preferably representing the monovalent —CH(CH
3
)C
6
H
5
radical and the symbol R
4
preferably representing the monovalent —CH
2
CH
2
C
6
H
5
radical,
(8) the symbols R
5
and R
6
are identical and/or different and represent a monovalent functional group chosen from:
a monovalent primary amine of —R
7
—NH
2
type where R
7
is a linear, branched or cyclic alkyl radical having from 1 to 6 carbon atoms,
a monovalent secondary amine of —R
8
—NH—R
9
type where R
8
and R
9
, which are identical and/or different, are linear, branched or cyclic alkyl chains having from 1 to 6 carbon atoms,
a monovalent —(CH
2
)
a
(NHCH
2
CH
2
)
b
NH
2
radical where a and b are independent integers:
a is between 1 and 10, preferably 1 to 3,
b is between 0 and 10, preferably 0 or 1,
a monovalent —(CH
2
)
c
(OCH
2
CH
2
)
d
(OCH
2
CHCH
3
)
e
OH radical where c, d and e are independent integers:
c is between 1 and 20, preferably 1 to 10,
d is between 0 and 70, preferably 0 to 12,
e is between 0 and 70, preferably 0 to 15,
a monovalent —(CH
2
)
f
SH radical where f is an integer which can range from 1 to 10, preferably from 1 to 3,
a monovalent —(CH
2
)
g
—C(R)
2
—OH radical where g is an integer which can range from 1 to and preferably from 1 to 3, and R′ represents a hydrocarbon-comprising radical chosen from a linear or branched alkyl radical having from 1 to 4 carbon atoms, aryl radicals and alkylaryl radicals.
The values of percentages by weight relating to the compounds (a), (b) and (c) refer to the content of total solid matter in the crosslinkable composition, i.e. the solid matter of the three compounds (a), (b) and (c).
According to an advantageous form in accordance with the invention, the properties of resistance to scratching are optimized with a crosslinkable composition comprising (a) 20 to 40 weight % of polyisocyanate, preferably 30%, (b) 60 to 80 weight % of hydroxylated acrylic oligomer, preferably 70%, and (c) 1 to 4 weight % of a silicone oil of formula (I), preferably 2 to 3%, such that the NCO/XH molar ratio in the polyurethane films is between 0.5 and 2 and preferably between 0.80 and 1.1. NCO is the isocyanate functional group of the polyisocyanate and XH represents OH, NH and SH, which are the reactive functional groups of the acrylic polymer and those of the functionalized silicone oil.
The acrylic oligomer generally comprises between 0.1 and 10 weight % of hydroxyl groups. This percentage of hydroxyl groups is advantageously between 1 and 6% and more particularly between 2.5 and 4.5%.
The crosslinkable composition generally comprises a solvent such that the percentage by weight of the compounds (a), (b) and (c) with respect to the crosslinkable composition comprising a solvent is between 40 and 80% and preferably of the order of 50 to 60%. Various types of solvent can be used, for example methyl amyl ketone, butyl acetate and the product Solvesso 100 (resulting from a petroleum fraction).
The structure of the silicone oil present in the composition according to the invention is chosen such that the said oil is weakly miscible in the system composed mainly of the mixture of acrylic oligomer and of polyisocyanate. On this subject, the presence of the 2-phenylethyl and 1-phenylethyl groups within the structure of the silicone oil controls the degree of miscibility of the chain of the silicone oil in the acrylic oligomer and polyisocyanate system. The level of Si units of the silicone oil modified by these groups varies from 20 to 40%.
In addition, according to another advantageous form of the invention, the crosslinkable composition comprises silicone oils functionalized with units of HALS type. In this case, at least a portion of the symbols R
5
and R
6
, which are alike and/or different, of the silicone oil represent a monovalent functional group chosen from a residue of formula (II) defined below such that the ratio of the number of functional groups of formula (II) to the number of Si units of the silicone oil is between 5 and 15%:
in which:
(1) the monovalent R
11
radicals are identical and/or different and are chosen from linear or branched alkyl radicals having 1 to 3 carbon atoms and the phenyl radical,
(2) the monovalent R
12
radical represents a hydrogen radical,
(3) the R
10
radical is a divalent hydrocarbon-comprising radical chosen from:
Branlard Paul
Guennouni Nathalie
Karrer Philippe
Mignani Gerard
Rhodia Chimie
Woodward Ana
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