Compositions: coating or plastic – Coating or plastic compositions – Silicon containing other than solely as silicon dioxide or...
Reexamination Certificate
2001-06-29
2003-11-25
Wood, Elizabeth D. (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Silicon containing other than solely as silicon dioxide or...
C106S287130, C106S287140, C106S002000, C428S447000
Reexamination Certificate
active
06652640
ABSTRACT:
This invention relates to surface treating agents for treating surfaces of glass, glass lenses, mirrors, plastics, plastic lenses, metals, ceramics, porcelain and earthenware to form antifouling coatings which are tack-free, non-adherent to dust and debris, and repellent to both water and oil. It also relates to articles treated with the surface treating agents.
BACKGROUND OF THE INVENTION
It is known in the art to coat optical lenses such as eyeglass lenses and camera lenses with layers of cured silicone and/or fluorocarbon polymers in order to impart antifouling property and water repellency to the lenses. The treating agents proposed thus far to this end are typified by trifunctional organosilicon compounds such as C
8
F
17
C
2
H
4
SiCl
3
and C
4
F
9
C
2
H
4
Si(NH)
3/2
or partial hydrolyzates thereof as disclosed in JP-A 60-221470.
When substrates are treated with such trifunctional compounds alone, the surface is covered with only a polymer having a three-dimensional structure so that the surface remains flexible or rather tacky. Undesirably, dust and debris will adhere to such surface, and fingerprints resulting from hand touch are left stuck thereto.
Then JP-A 11-116809 and JP-A 11-116810 propose surface treating agents comprising a trifunctional fluorinated silazane compound and an organopolysiloxane containing a hydrolyzable group such as alkoxy group. However, the hydrolyzable group such as alkoxy group can interfere with cure.
SUMMARY OF THE INVENTION
Therefore, an object of the invention is to provide a surface treating agent which has antifouling, water repellent and oil repellent properties and is effectively curable to form an antifouling coating whose surface is tack-free and non-adherent to dust and debris. Another object is to provide a surface treated article.
It has been found that the reaction product obtained by reacting a mixture of an organosilicon compound of the general formula (1) and an organosilicon compound of the general formula (2) with ammonia, or a mixture of the reaction product obtained by reacting an organosilicon compound of the general formula (1) with ammonia and the reaction product obtained by reacting an organosilicon compound of the general formula (2) with ammonia is effective as a surface treating agent. When surfaces of substrates such as glass, glass lenses, mirrors, plastics, plastic lenses, metals, ceramics, porcelain and earthenware are treated therewith, antifouling coatings are formed on the substrate surfaces, which coatings are tack-free, non-adherent to dust and debris, and repellent to both water and oil.
Herein Rf is a fluorinated organic group of 1 to 12 carbon atoms, R
1
is a monovalent hydrocarbon group of 1 to 10 carbon atoms, X is a halogen atom, and “a” is 0, 1 or 2.
Herein R
2
, which may be the same or different, is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R
3
is a monovalent hydrocarbon group of 1 to 10 carbon atoms which may contain a fluorine atom, R
4
is a hydrolyzable group of the general formula (3), R
5
and R
6
are as defined for R
2
or R
4
, k is an integer of 0 to 100, m is an integer of 0 to 100, n is an integer of 0 to 5, k+m+n is from 0 to 200, with the proviso that the compound of formula (2) contains at least one R
4
per molecule.
Herein R
7
is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R
8
is a divalent hydrocarbon group of 2 to 10 carbon atoms or oxygen atom, X is a halogen atom, and “b” is 0, 1 or 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the first embodiment of the invention, the surface treating agent contains the reaction product obtained by reacting a mixture of (A) an organosilicon compound of the general formula (1) and (B) an organosilicon compound of the general formula (2) with ammonia.
Herein Rf is a fluorinated organic group of 1 to 12 carbon atoms, R
1
is a monovalent hydrocarbon group of 1 to 10 carbon atoms, X is a halogen atom, and “a” is 0, 1 or 2.
Herein R
2
, which may be the same or different, is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R
3
is a monovalent hydrocarbon group of 1 to 10 carbon atoms which may contain a fluorine atom, R
4
is a hydrolyzable group of the general formula (3), R
5
and R
6
are as defined for R
2
or R
4
, k is an integer of 0 to 100, m is an integer of 0 to 100, n is an integer of 0 to 5, k+m+n is from 0 to 200, with the proviso that the compound of formula (2) contains at least one R
4
per molecule.
Herein R
7
is a monovalent hydrocarbon group of 1 to 10 carbon atoms, R
8
is a divalent hydrocarbon group of 2 to 10 carbon atoms or oxygen atom, X is a halogen atom, and “b” is 0, 1 or 2.
In formula (1), the fluorinated organic groups represented by Rf are not critical as long as they have 1 to 12 carbon atoms. Typical are perfluoroalkylene groups bound to a silicon atom directly or through an alkylene group. Preferred groups are perfluoroalkylene groups represented by
C
p
F
2p+1
C
q
H
2q
—
wherein p is an integer of 1 to 8, preferably 4 to 8, q is an integer of 0 to 10, preferably 2 or 3, and p+q is from 1 to 12. Specific examples are CF
3
—C
2
H
4
—, C
4
F
9
—C
2
H
4
—, C
8
F
17
—C
2
H
4
— and C
8
F
17
—C
3
H
6
— groups. Examples of the monovalent hydrocarbon groups represented by R
1
include alkyl groups such as methyl, ethyl, propyl, butyl and hexyl, alkenyl groups such as vinyl and allyl, aryl groups such as phenyl and tolyl, and aralkyl groups such as benzyl. Of these, methyl, ethyl, propyl and phenyl are preferred, with methyl being especially preferred.
In formulas (2) and (3), the monovalent hydrocarbon groups represented by R
2
, R
3
and R
7
are as exemplified for R
1
. The monovalent hydrocarbon groups represented by R
3
may contain fluorine atoms, and such groups correspond to, for example, the foregoing alkyl, alkenyl, aryl and aralkyl groups in which some or all of the hydrogen atoms attached to carbon atoms are substituted with fluorine atoms as well as those groups exemplified for Rf, especially perfluoroalkylene groups of C
p
F
2p+1
C
q
H
2q
—. Examples of the divalent hydrocarbon groups represented by R
8
include alkylene groups such as ethylene, propylene, butylene and hexylene. Exemplary halogen atoms represented by X are chlorine and bromine, with chlorine being especially preferred. Letter k is an integer of 0 to 100, preferably 0 to 50; m is an integer of 0 to 100, preferably 0 to 25; n is an integer of 0 to 5; and k+m+n is from 0 to 200, preferably from 0 to 70.
The organosilicon compound of formula (2) contains per molecule at least one R
4
, that is, hydrolyzable group of formula (3). The hydrolyzable group may be attached to a side chain or an end of the polysiloxane molecule or both.
Examples of the organosilicon compound of formula (2) are given below.
Herein, R
2
, R
3
, R
7
, R
8
, X, k, m, n, and b are as defined above. Preferably b is 0.
Illustrative, non-limiting, examples of the organosilicon compound of formula (2) are given below.
The mixing ratio of (A) the organosilicon compound of formula (1) and (B) the organosilicon compound of formula (2) is not critical although it preferably ranges from 1:0.1 to 0.1:1, especially from 0.5:1 to 1:0.5 on a weight basis. Outside the range, less amounts of the organosilicon compound of formula (1) may lead to shortage of oil repellency whereas less amounts of the organosilicon compound of formula (2) may result in rather tacky surface coatings. In either case, the desired antifouling property may not be obtained.
In reacting the mixture of organosilicon compounds of formulas (1) and (2) with ammonia, the mixture is previously dissolved in a suitable solvent. The solvent used herein is not critical although solvents containing fluorine atom such as m-xylene hexafluoride, pentafluorodichloropropane and octadecafluorooctane are preferred because of good solubility.
For reaction with ammonia, ammonia gas is blown into the mixture so that ammonia reacts with halogen atoms on the organosilicon compounds of formulas (1) and (2). As to the reaction conditions, at lea
Asai Mitsuo
Uehara Hitoshi
Millen White Zelano & Branigan P.C.
Shin-Etsu Chemical Co. , Ltd.
Wood Elizabeth D.
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