Surface treatments with bifunctional perfluoropolyether...

Details Surface treatments with bifunctional perfluoropolyether... Surface treatments with bifunctional perfluoropolyether...

1999-11-29

2001-04-24

Szekely, Peter (Department: 1714)

Coating processes

With post-treatment of coating or coating material

Heating or drying

C427S389800, C427S389900, C427S391000, C427S392000, C427S393500, C427S394000, C427S395000, C427S396000, C427S397000, C427S393000

Reexamination Certificate

active

06221434

ABSTRACT:

This application claims priority from Italian Patent Application No. MI98A002605 filed Dec. 1, 1998;
BACKGROUND OF THE INVENTION
The present invention relates to the surface treatment with functional derivatives of perfluoropolyethers, particularly in order to provide oil- and/or water-repellency.
It is known in the art to use, for the surface treatment, fluorinated acrylic compounds and polymers containing perfluoroalkanes or perfluoropolyethers in graft position (U.S. Pat. Nos.2,803,615; 2,839,513; 2,995,542; 3,356,628 in the name of 3M; U.S. Pat. No.3,814,741 in the name of this same Applicant), surfactants and monofunctional derivatives with a perfluoroalkyl chain, for example perfluoroalkylphosphates for the oil-repellency treatment of paper (U.S. Pat. No.5,271,806), silicones and fluorosilicones, and polyurethanes fluorinated by bifunctional perfluoropolyethers (U.S. Pat. Nos. 4,983,666; 5,068,135 in the name of this same Applicant).
In particular, U.S. Pat. No.4,499,146 discloses the use of perfluoropolyethers with perfluoroalkyl endgroups to protect building materials such as marble, stone, bricks, cement and the like against the action of atmospheric agents and pollutants. These products provide oil- and/or water-repellency, are characterized by high permeability to gases and vapors and do not alter the appearance and color of the materials to which they are applied. However, on porous materials the protective action of these compounds decreases over time as a consequence of the migration of the perfluoropolyethers from the surface toward the inside of the material.
Better results have been reported for the use of perfluoropolyethers functionalized with groups capable of anchoring the product to the substrate to be protected. The use of said derivatives, functionalized with carboxyl, ester, amide, hydroxyl, diisocyanate, epoxy, silane groups etcetera to protect building materials against the action of atmospheric agents and pollutants is disclosed in U.S. Pat. No.4,745,009. Various other functional derivatives of perfluoropolyethers are disclosed in U.S. Pat. No.4,085,137.
Moreover, U.S. Pat. No.3,492,374 discloses the use of phosphoric esters with a perfluoropolyether chain having the formula I
[XCF
2
CF
2
O(CFXCF
2
O)
x
CFXCH
2
O]
2
PO(OM)  I
where X is —F or —CF
3
; x is an integer from 1 to 8; M is a cation, such as H
+
, an alkaline metal ion, or an ammonium ion, optionally alkyl-substituted;
in order to impart oil-repellency to materials such as fabrics, fibers, hide, paper, plastic claddings, wood, ceramics.
Besides, EP-A-603697 discloses the use of a compound having the formula II
where L is a divalent organic group; m=1; Y is —F or —CF
3
; Z
+
is chosen among H
+
, M
+
where M is an alkaline metal, N(R)
4
+
where the R groups are mutually identical or different and are H or C
1
-C
6
alkyls; R
f
is a chain of polyperfluoroalkylene oxide,
for imparting oil- and water-repellency to surfaces made of ceramics, particularly Tuscany terracotta tiles, so-called “cotto toscano”.
The use of the same compounds to impart oil- and water-repellency to cellulose materials, metallic materials, glass-like materials, cement, marble and the like is disclosed in EP-A-687533.
SUMMARY OF THE INVENTION
The aim of the present invention is to provide a method for treating surfaces which is specific for certain types of surfaces, particularly paper, terracotta tiles so-called “cotto”, wood and fabrics and is adapted to obtain treated surfaces which have a better performance and longer permanence and durability of the treatment.
Within the scope of this aim, an object of the present invention is to provide surface treatments for imparting oil- and/or water-repellency to the surfaces to be treated and for imparting at the same time a better handle (for example for fabrics) than known treatments, such as those with acrylic compounds.
Another object of the present invention is to provide surface treatments which allow to obtain better oil- and water-repellency properties for the same applied product quantity with respect to treatments using monofunctional compounds (for example for wood).
This aim, these objects and others which will become apparent hereinafter are achieved by the surface treatment method for imparting oil- and/or water-repellency according to the present invention, which comprises the step of applying to the surface to be treated at least one compound having the formula III
ACF
2
O—(CF
2
O)
n
(C
2
F
4
O)
m
—CF
2
—B  III
where n=1-20, m=1-20 and A and B are reactive functional groups chosen independently from the group consisting of:
a) CONHR, where R=C
n
H
2n+1
with n=1-30, for example R=C
18
H
37
,
b) CH
2
OH,
c) CONH(X)
m′
SiR
1
n″
(OR′)
3−n″
where n″=0-2, R
1
and R′ identical or different, are C
r
H
2r+1
alkyl radicals, where r=1-4 and X X=CHR″, there m′m=1-20, and R″ can be H or CH
3
, optionally containing heteroatoms, for example CONH(CH
2
)
3
Si(OR′)
3
, where R′=CH
3
, C
2
H
5
,
d) —[CH
2
O(R′″O)
p
]
k
—P(O)(OH)
3−k
, where R′″ is an alkylene radical, for example C
2
H
4
or C
3
H
6
, p=1-10 and k=1, 2, said method being characterized in that said composition (1) comprises said compound at a suitable concentration and (2) is applied in an amount suitable to obtain substantially at least one monolayer of said compound on the surface to be treated, said reactive groups being chosen according to the nature of the surface to be treated so as to provide a strong interaction with the surface to be treated.
DETAILED DESCRIPTION
The Applicant has found that the reactive endgroups of the above-mentioned group are capable of specifically interacting with various types of surfaces, ensuring thereby the bonding of the compound to the surface to be treated in a stable manner, during the step for treatment and post-treatment of the substrate.
In order to carry out the present invention it is possible to use a compound having the formula III in which the groups A and B are mutually identical or different or it is possible to use in combination different compounds having the formula III with different and mutually compatible endgroups.
Advantageously, the method according to the present invention when used for treating wood surfaces uses a composition which contains the compound having the formula III, in which the reactive functional endgroups A and B are amide groups having the formula CONHR, where R is an alkyl group, for example C
18
H
37
. Preferably, the compound is included in a hydrocarbon-based solution, but it can be used in different forms, including water-based emulsion. Interaction between the endgroups and the surface of the wood is not particularly strong, since it is based only on hydrophobic interaction. The presence of two endgroups considerably reinforces the interaction, since removal of the treatment agent is dependent on the simultaneous breakaway of the two groups from the surface, which is statistically far less likely than the breakaway of a single bond.
The concentration of the compound in the composition applied to the wood surface is suitable to provide at least one monolayer of compound on the surface to be treated, and is conveniently comprised between 0.01 and 40% and preferably between 1 and 20% by weight.
Conveniently, when the method according to the present invention is used for the treatment of surfaces or fabrics, for example cotton, the composition that is applied comprises a compound having the formula III in which the reactive endgroups are silane groups, for example having the formula CONH(CH
2
)
3
Si(OR)
3
, where R′ is an alkyl group, preferably methyl or ethyl.
The interaction between the functional endgroup and the surface is the typical interaction of silanes, forming strong bonds with the hydroxylated surface. The presence of the two functions on the mo

Affiliated with

Also associated with

Rating

Surface treatments with bifunctional perfluoropolyether... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Surface treatments with bifunctional perfluoropolyether..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface treatments with bifunctional perfluoropolyether... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2435899