Compositions: coating or plastic – Coating or plastic compositions – Silicon containing other than solely as silicon dioxide or...
Reexamination Certificate
2002-09-23
2004-08-17
Brunsman, David (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Silicon containing other than solely as silicon dioxide or...
C106S287140, C106S287160
Reexamination Certificate
active
06776834
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to composition and a process for treating substrates containing silicon (Si), especially siliceous containing substrate, for rendering them water, oil, stain and dirt repellent.
STATE OF THE ART
EP-A-1.171.396 (U.S. Pat. No. 6,379,448) teaches siliceous substrate provided with a fluoro aliphatic silane layer, said layer having excellent mechanical and chemical properties. According to examples, the siliceous substrate is treated with a composition which is prepared before contacting the surface to be treated, by mixing a composition comprising silane and an organic solvent for said silane, and a composition comprising an organic solvent and concentrated hydrochloric acid (HCl). The pot live of the composition when prepared is limited to less than 5 days.
WO 02/30848 teaches a composition for treating a substrate comprising a fluorinated polyether silane, an organic or inorganic acid, water and an organic solvent. Tests have been made by applicant with composition according to said document (composition sold under the trade name ECC-1000). The pot life of the composition is limited whereby the composition has to used in less than 1 day. Furthermore, the layer obtained on a glass substrate with this composition had mechanical properties and chemical resistance properties which were lower than the properties of the layer prepared as taught in EP-A-1.171.396.
U.S. Pat. No. 6,300,379 teaches a method for improving the stability of an aqueous solution comprising a fluoro organo silane, by including in the aqueous composition 1 to 10% by weight based on the total weight of the aqueous solution a surfactant, and 1 to 9% by weight of a glycol ether co-solvent. The amount of fluoro organo silane present in the aqueous composition is comprised between 0.01 and 3%.
The content of said documents is incorporated in the present specification by reference.
Applicant has now discovered that by using a composition containing an organo fluoro silane, an amount of organic solvent sufficient for dissolving the organo fluoro silane and an amount of ammonium or phosphonium compound lower than the amount of organo fluoro silane, it was possible to increase the mechanical properties of the coating and its chemical resistance, even if the organo fluoro silane content of the composition was less than 0.1%. This means that the composition can have a very low content of fluoro silane (while not disturbing the excellent mechanical properties), whereby possible ecological risk can be drastically reduced. Furthermore, it has been observed that compositions substantially water free were still efficient more than 1,2,3 and even 6 months after their preparation, whereby rendering it possible to sell ready to use composition.
BRIEF DESCRIPTION OF THE INVENTION
The invention relates to a composition suitable for improving the properties of the fluoro silane layer, especially the mechanical properties thereof, in particular to improve the abrasion resistance.
The composition for treating a siliceous containing substrate of the invention comprises:
a first amount of a substantially water insoluble fluoro silane (such as disclosed in EP-A-1.171.396), advantageously fluorinated polyether silane (such as disclosed in WO 02/30848) of the formula:
R
f
1
—[—Q—SiY
3-x
R
1
x
]
y
wherein R
f
1
represent a monovalent or divalent polyfluoropolyether group, Q represents an organic divalent linking group, R
1
represents a C1-C4 alkyl group, Y represents a hydrolysable group, x is 0 or 1 and y is 1 or 2;
one or more organic solvents in a quantity sufficient for solubilizing at least substantially completely said first amount of water insoluble polyether silane;
possibly water;
possibly one or more organic or inorganic acid, and
one or more compounds comprising one or more ammonium and/or phosphonium groups, the weight ratio [compounds comprising one or more ammonium and/or phosphonium]/[water insoluble fluoro silane] being advantageously greater than 0.005, preferably greater than 0.01.
The composition of the invention is advantageously free of film forming organic polymer, organic polymer and silane without fluoro atoms. The composition of the invention is advantageously also free of organopolysiloxane. According to a detail, the composition of the invention is free or substantially free of water soluble fluoro silane. The composition of the invention comprises thus preferably as material suitable for making a coating or layer on the substrate, substantially only water insoluble fluoro silane.
The pH of the composition (measured at 25° C. by using a LiCl electrode with an open sleeve) is lower than 9, advantageously comprised between 1 and 7.5, preferably comprised between 2 and 7, for example greater than 4 and lower than 7, such as 4, 4.5, 5, 5.5, 6.
According to an embodiment, the amount of ammonium and/or phosphonium compound present in the composition is lower than the first amount, preferably lower than 0.5 time the first amount, most preferably lower than 0.1 time the first amount. It seems that the ammonium and/or phosphonium compound present in the composition acts as a means organizing the reaction of the fluoro organosilane with the face of the siliceous containing substrates, whereby enabling better bonds between the silane layer and the substrate.
The composition of the invention is substantially water free. When the composition is completely water free, the composition is advantageously contacted with the substrate in a humid atmosphere.
The composition of the invention comprises more than 50% by weight organic solvent, advantageously more than 75% by weight, preferably more than 90% by weight, most preferably more than 95% by weight, such as more than 99%, more than 99.5%, or even more than about 99.8%. The composition can be a concentrated composition, for example containing 5% fluoro silane, 1% ammonium/phosphonium compound and 94% organic solvent, said composition being then diluted with organic solvent before its use, so as to apply on the surface to be coated a composition containing advantageously less than 0.5% fluoro silane.
The composition of the invention can comprise one or more carboxylic acids, such as formic acid, citric acid, acetic acid, phthalic acid, tartaric acid, or fluorinated organic acids, such as those disclosed in WO 02/30848. Inorganic acids, such as sulfuric acid, phosphoric acid, hydrochloric acid (HCl), hydrofluoric acid (HF), nitric acid, and mixtures thereof are less preferred. However, the composition can comprise such inorganic acids, especially nitric acid and phosphoric acid. When using acids, the acids or the amount present in the composition will be selected so as to not damage or attack the face to be coated.
The solvent used in the composition of the invention is advantageously selected with the group consisting of aliphatic alcohols, such as methanol, ethanol, isopropylalcohol, ketones, acetone, methyl ethyl ketone, esters, ethers, etc. Suitable organic solvents can be quickly determined by the man skilled in the art by trying to solubilize the water insoluble fluoro silane in the solvent or solvent system he wants to use. Most preferably, the composition comprises at least one halogeno solvent, for example chlorinated solvents, such as chlorinated hydrocarbons, 1,2,2 trichloro-1,1,2-trifluoroethane, fluorinated solvents, such as fluorinated hydrocarbons, hydrofluoroethers, mixtures thereof. Typical examples are perfluorohexane, perflorooctane, pentafluorobutane, CF
3
CFHFHCF
2
CF
3
, methylperfluoroethers, ethyl perfluorobutyl ether, trifluoromethyl-3-ethoxydodécafluorhexane, ethyl nonafluoro isobutylether, methyl nonafluoro butyl ether, and mixtures thereof. Preferred fluoro solvents are trifluoromethyl-3-ethoxydodécafluorhexane, ethyl nonafluoro isobutylether, ethyl nonafluoro butylether, methyl nonafluoro butyl ether, methyl nonafluoro isobutyl ether and mixtures thereof.
Advantageously, the ammonium and/or phosphonium compound is present in the composition at least partly in the form
Brunsman David
Darby & Darby
ICT Coatings N.V.
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