Compositions – Humidostatic – water removive – bindive – or emissive
Reexamination Certificate
2001-11-29
2004-11-23
Toomer, Cephia D. (Department: 1714)
Compositions
Humidostatic, water removive, bindive, or emissive
C134S002000, C134S042000
Reexamination Certificate
active
06821454
ABSTRACT:
The present invention relates to a method for the substantially complete removal of water from surfaces of various articles. The problem of the water removal from manufactured articles is particularly felt in the field of electronics, fine mechanics and finishing of precious metals.
From patent application EP 826,714 in the name of the Applicant compositions are known formed by a (per)fluoropolyether having number average molecular weight in the range 300-1,500 and by a fluorinated non ionic additive which can have both end groups of oxyethylene type or one end group of oxyethylene type and the other of fluorinated or perfluorinated type; in the additive structure the ratio by weight (K) between (per)fluorinated part and hydrogenated part being in the range 1.50-3.50. In the examples an additive is used having a perfluorinated end group and as perfluoropolyether solvent a compound of formula:
CF
3
O(C
3
F
6
O)
1,7
(CF
2
O)
0,1
CF
3
having molecular weight of about 450. The results obtained in the Examples are extremely good and effective in the removal of water from surfaces of various articles. However the additives having perfluorinated end groups are obtained by a particularly expensive process.
The need was felt to have available additives having a fluorinated end group able to give the same removal efficiency of additive with perfluorinated end group. In fact the additives having fluorinated end groups can be produced with an industrial process having higher yields and therefore more advantageous from an industrial point of view. The Applicant has verified that repeating the Examples of said patent application with additives having a fluorinated instead of a perfluorinated end group, the water is removed from the substratum in a less effective extent than using the same additive having the perfluorinated end group. See the comparative Examples.
There was therefore the need to find compositions, containing a perfluoropolyether solvent and an additive with a fluorinated end group, to make possible the water removal from the substratum in a likewise effective way than using the additive with the perfuorinated end group.
An object of the present invention is a method for removing water from surfaces of various articles, comprising the steps of covering said surface with a composition having a specific weight higher than that of the water and subsequently removing water from the composition by skimming, wherein a composition consisting essentially of the following components is used:
A) a non ionic additive having a fluoropolyether structure with a fluorinated T end group containing one chlorine atom, having the following formula:
T-OR
f
(CFY)-L (I)
wherein
L=X—CH
2
CH
2
(OCH
2
CH
2
)
n
B (Ia)
wherein:
X=CH
2
O; CH
2
NR″; CONR″; CH
2
OCH
2
CH
2
NR″; CH
2
OCOCH
2
O;
B=OH; SH; NHR″; OCH
3
; OCOCH
3
,
with R″=H; C
1-3
alkyl,
T is a fluorinated radical selected from ClCF
2
CF(CF
3
)—, CF
3
CFClCF
2
—, ClCF
2
CF
2
—, ClCF
2
—,
Y=CF
3
or F,
the radical R
f
being of (per)fluoropolyether type;
being in said additive of formula (I):
the number average molecular weight of the fluoroether part T-OR
f
— in the range 400-2,000,
the ratio by weight (K) between the fluorinated part and the hydrogenated L part of the additive is in the range 1.50-4.00; the n parameter in formula (Ia) being such as to meet said ratio;
B) a perfluoropolyether having number average molecular weight in the range 300-900,
the ratio K
I
between the number average molecular weight of the fluoropolyether part T-OR
f
— of the additive and the number average molecular weight of component B) being higher than 1.60.
The number average molecular weight of the fluoroether part T-OR
f
— of the compounds of formula (I) component A) is preferably in the range 500-1,200, still more preferably in the range 600-1,000.
The perfluoropolyether component B) has number average molecular weight preferably in the range 300-650.
The radical R
f
of (per)fluoropolyether type preferably comprises repeating units statistically distributed along the polymer chain selected from: (CF
2
CF
2
O), (CFYO) wherein Y is equal to F or CF
3
, (C
3
F
6
O); (CF
2
(CF
2
)
z
O) wherein z is an integer equal to 2 or 3; (CF
2
CF(OR
f′
)O), (CF(OR
f′
)O) wherein R
f
, is equal to —CF
3
, —C
2
F
5
—C
3
F
7
; CR
4
R
5
CF
2
CF
2
O wherein R
4
and R
5
are equal to or different from each other and selected between Cl or perfluoroalkyl, for example having 1-4 carbon atoms.
If the ratio K
I
is lower than or equal to 1.60 (see the comparative Examples) the composition containing the additive does not result effective in the substantially complete removal of water. This was not inferable from EP 826,714; in fact in the Examples of this patent application the ratio K
I
calculated between the molecular weight of the fluorinated part of the additive and the molecular weight of component B) is 1,46 and therefore lower than the limit that the Applicant has unexpectedly found for the use according to the method of the present invention of the additives component A) having a fluorinated end group containing one chlorine atom.
To obtain a composition to be used in the method according to the present invention it is further necessary that the ratio K between the fluorinated part and the hydrogenated part of the additive lies within the above limits.
When the ratio K is outside the above limits the additive is not effective in the substantial removal of water from the substratum.
The following (per)fluoropolyether R
f
which comprise the following repeating units can in particular be mentioned as the preferred ones:
(a) —(CF
2
CF(CF
3
)O)
a
(CFYO)
b
—
wherein Y is F or CF
3
; a and b are integers such that the molecular weight is in the above range; a/b is in the range 10-100;
(b) —(CF
2
CF
2
O)
c
(CF
2
O)
d
(CF
2
(CF
2
)
z
O)
h
—
wherein c, d and h are integers such that the molecular weight is within the above range; c/d is in the range 0.1-10; h/(c+d) is in the range 0-0.05, z has the above value, h can be equal to 0;
(c) —(CF
2
CF(CF
3
)O)
e
(CF
2
CF
2
O)
f
(CFYO)
g
—
wherein Y is F or CF
3
; e, f, g are integers such that the molecular weight is within the above range; e/(f+g) is in the range 0.1-10, f/g is in the range 2-10;
(d) —(CF
2
O)
j
(CF
2
CF(OR
f″
)O)
k
(CF(OR
f″
)O)
l
—
wherein: R
f″
is —CF
3
, —C
2
F
5
, —C
3
F
7
; j,k,l are integers such that the molecular weight is within the above range; k+l and j+k+l are at least equal to 2, k/(j+l) is in the range 0.01-1,000, l/j is in the range 0.01 and 100;
(e) —(CF
2
(CF
2
)
z
O)
s
—
wherein s is an integer such as to give the above molecular weight, z has the already defined meaning;
(f) —(CR
4
R
5
CF
2
CF
2
O)
j
wherein R
4
and R
5
are equal to or different from each other and selected from H, Cl or perfluoroalkyl, for example having 1-4 carbon atoms, j′ being an integer such that the molecular weight is the above mentioned one;
(g) —(CF(CF
3
)CF
2
O)
j″
—
j′ being an integer such to give the above molecular weight.
These structures comprising the mentioned repeating units and the methods for their preparation are described in patent GB 1,104,482, in U.S. Pat. No. 3,242,218, U.S. Pat. No. 3,665,041, U.S. Pat. No. 3,715,378, U.S. Pat. No. 3,665,041, EP 148,482, U.S. Pat. No. 4,523,039, U.S. Pat. No. 5,144,092, and for the functional derivatives see U.S. Pat. No. 3,810,874. All these patents are herein incorporated by reference.
The value K
I
is preferably higher than 2.00 and still more preferably in the range 2.00-3.00.
The perfluoropolyether component B) preferably has the following structure:
T′—O—R
f
-T″
wherein:
R
f
has the above meaning;
T′ and T″, equal or different, are selected from —CF
3
, —C
2
F
5
, —C
3
F
7
.
Particularly preferred structures are the following:
T′O(C
3
F
6
O)
a″
(CFYO)
b″
T″ (III)
wherein Y=F or CF
3
, a″ and b″ are integers such t
Fontana Simonetta
Visca Mario
Arent & Fox PLLC
Ausimont S.p.A.
Toomer Cephia D.
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