KR100194250B1 - Water repellent surface treatment with integrated primer - Google Patents

Abstract

Compositions that form a water repellent surface on a substrate, such as glass, plastic, metal, organic polymer coated substrates or inorganic coated substrates, have the general formula R _m R ' _n SiX _4-mn , where R is a perfluoroalkylalkyl radical R 'is a vinyl or alkyl radical, the sum of m and n is less than 4 and X is a halogen, alkoxy or acyloxy radical) and a silane or siloxane capable of hydrolyzing with silica gel. Mixtures of compounds. The water resistance measured by the contact angle of water droplets on the surface of the substrate treated with the above compound is more than that of the surface treated with the same perfluoroalkylalkylsilane without using silane or siloxane which can be hydrolyzed with silica gel. It is durable.

Description

Water repellent surface treatment with integrated primer

The present invention discloses US patent application Ser. No. 07 / 589,235, filed on September 28, 1990, which is part of US Patent Application No. 07 / 503,587 (Patent 4,983,459), filed April 2, 1990. US Patent Application Serial No. 09/220353, filed March 30, 1994, filed on March 30, 1994, part of US Patent Application No. 08 / 363,803, filed on December 27, 1994 Part of the issue is pending application.

FIELD OF THE INVENTION The present invention generally relates to the field of surface treatment, more particularly to the formation of water repellent surfaces on various substrates, and most particularly to improving the durability of water repellent surfaces.

U.S. Patent No. 5,314,731 to Yoneda et al. Discloses 1 selected from the first outermost layer and isocyanate silane compound and hydrolyzable silane compound obtained by treatment with a compound that forms a surface having a contact angle of at least 70 ° with respect to water. Surface-treated substrates having two or more surface treated layers of a second sublayer obtained by treatment with the above reactive silane compounds are described.

United States Patent Nos. 4, 983, 459 and 4,997,684 to Franz et al. Describe methods and products for providing a durable waterproof surface by treating glass with perfluoroalkylalkylsilanes and fluorinated olefin telomers. do.

U.S. Patent No. 5,308,705 to Franz et al. Discloses treating substrates other than glass with perfluoroalkylalkylsilanes and fluorinated olefin telomers to provide waterproof surface properties.

Goodwin, US Pat. No. 5,328,768, discloses a glass substrate whose surface is first treated with a silica primer layer and secondly with perfluoroalkylalkylsilane.

The present invention provides a substrate surface having high water repellency and high lubricity. The waterproofness and antifouling property of the substrate surface is improved by applying the perfluorinated alkylalkylsilane compound and the hydrolyzable silane or siloxane compound to the substrate surface. Hydrolyzable silane or siloxane compounds are compounds that can hydrolyze condensate to form silica gel and act as an integrated primer. The surface treatment of the present invention provides a surface with increased waterproof and antifouling properties without requiring a separate primer layer.

High water repellency and lubricity are provided by perfluoroalkylalkylsilanes. Hydrolyzable silanes or siloxanes provide reactive drying of the solvent. The perfluoroalkylalkylsilanes and hydrolyzable silane or siloxane surface treatments of the invention also provide increased wear resistance to the substrate surface. Increased resistance to humidity, ultraviolet radiation and mechanical wear is provided by silane or siloxane compounds that can be hydrolysable to silica gel.

The rainfall and antifouling properties provided by the plot of perfluoroalkylalkylsilanes on the substrate surface are perfluoroalkylalkyls and mixtures of silanes, siloxanes or silanes and / or siloxane compounds that can be hydrolyzed into silica gel prior to application. Increased by mixing the silanes. According to the present invention, a silane which can be hydrolyzed into silica gel by applying a silane, siloxane or a mixture of silane and / or a siloxane compound and a mixture of perfluoroalkylalkylsilane to the glass surface, A coating that is more durable than that formed without the use of siloxane or a mixture of silane and / or siloxane compounds is formed.

Perfluoroalkylalkylsilanes and hydrolyzable silanes and / or siloxanes are preferably the surface of the substrate as a colloidal suspension or solution, preferably in an aprotic solvent, preferably in an alkane or alkane mixture, or in a fluorinated solvent. It is applied to form the product of the present invention. Preferred solutions of the invention are applied to the substrate surface using any conventional technique such as dipping, spilling, wiping or spraying. The silane reacts with the substrate surface to remove excess solution, providing a durable, water resistant, lubricious surface with improved wear resistance. The present invention provides the durability benefits of the primer, without using the additional step of applying a separate primer layer. The use of fully hydrolyzable silanes and / or siloxanes has been found in silane surface treatment, as measured by Cleveland Condensing Cabinet, QUV (using FS40 or B313 lamps), wet sled wear tests. Improved humidity, ultraviolet light and wear resistance resulting in longer useful product life.

Suitable silanes that can be hydrolyzed with silica gel have the general formula SiX ₄ , wherein X is a hydrolyzable radical generally selected from the group of halogen, alkoxy and acyloxy radicals.

Preferred silanes are those in which X is preferably chloro, bromo, iodo, methoxy, ethoxy and acetoxy. Preferred hydrolyzable silanes include tetrachlorosilane, tetramethoxysilane and tetraacetoxysilane.

Suitable siloxanes are those wherein X is selected from the group of halogen, alkoxy and acyloxy radicals and has the general formula Si _y O _z X _4y-2z wherein y is at least 2, z is at least 1 and 4y-z is at least 0. Preferred hydrolyzable siloxanes include hexachlorodisiloxane, octachlorotrisiloxane and high oligomeric chlorosiloxanes.

Hydrolyzable silanes or siloxanes provide two functions. One is to become a coating and to impart weather and abrasion resistance. Another action is to dry the solvent. Typical hydrocarbon solvents may contain 50-200 ppm water. Other solvents may have a higher water content. For example, a solvent containing 200 ppm water will have sufficient water to partially hydrolyze the 0.5% by weight concentration of perfluoroalkylalkylsilane. Fully hydrolyzable silanes or siloxanes may reduce or eliminate the water content of the solvent prior to adding the perfluoroalkylalkylsilane. In other words, partially hydrolyzed perfluoroalkylalkylsilanes may result in insufficient coating deposition or very poor durability.

Preferred perfluoroalkylalkylsilanes are of the general formula R _m R ' _n SiX _4-mn , wherein R is a perfluoroalkyl-alkyl radical; m is typically 1, n is typically 0 or 1, m + n is less than 4; R 'is a vinyl or alkyl radical, preferably methyl, ethyl, vinyl or propyl; X is preferably a radical such as halogen, acyloxy and / or alkoxy). Preferred perfluoroalkyl moieties in the perfluoroalkylalkyl radicals are CF ₃ to C ₃₀ F ₆₁ , preferably C ₆ F ₁₃ to C ₁₈ F ₃₇ , most preferably C ₈ F ₁₇ to C ₁₂ F ₂₅ ego; The alkyl moiety is preferably ethyl. R 'is preferably methyl or ethyl. Preferred radicals of X include hydrolyzable chloro, bromo, iodo, methoxy, ethoxy and acetoxy radicals. Preferred perfluoroalkylalkylsilanes according to the invention are perfluoroalkyl ethyltrichlorosilane, perfluoroalkylethyltrimethoxysilane, perfluoroalkylethyltriacetoxysilane, perfluoroalkylethyldichloro (methyl Silane and perfluoroalkylethyldiethoxy (methyl) silane.

Such preferred perfluoroalkylethylsilanes appear to react with the binding sites on the substrate surface in the molecular state. The strong surface bonds of the perfluoroalkylethylsilanes form a durable substrate surface that makes a large contact angle with the water droplets.

Suitable solvents include hexane, heptane, inorganic alcohols, acetone, toluene and naphtha. Preferred solvents are alkanes or halogenated hydrocarbon solvents such as trichlorotrifluoroethane and methylene chloride and perfluorinated organic compounds such as perfluorocarbons. The concentration of silane is about 0.005-50, preferably about 0.05-5%. The solvent may be simply evaporated as drying in air at ambient temperature, or excess solution may be removed, preferably by wiping.

The silane may crosslink to form a more durable coating, but preferably curing is obtained by heating the silane treated surface. Typically a curing temperature of at least 150 ° F. (about 66 ° C.) is preferred, and particularly preferably at least 200 ° F. (about 93 ° C.) A curing cycle of about 200 ° F. (about 93 ° C.) is suitable for about 30 minutes. Temperatures and shorter heating times may be more efficient: curing cycles of 2 to 5 minutes at 400 to 500 ° F. (about 204 to 260 ° C.), particularly about 3 minutes at about 470 ° F. (about 243 ° C.), are preferred. The olefin telomer is a silane composition described in US Pat. No. 5,308,705, preferably general formula C _m F _{2m + 1} CH = CH ₂ (wherein m is 1-30, preferably 1-16, more preferably Preferably 4 to 10. The substrate surface may optionally be contacted with a perfluoroalkylalkylsilane in vapor form.

The contact angles cited herein were subjected to the sessile drop method using a modified captive bubble indicator (Lord Manufacturing, Inc.), equipped with a Gartner Scientific Goniometer optical element. Measure by Place the surface to be measured horizontally and face up in front of the light source. The droplet is placed on top of the surface in front of the light source to see the contour of the stuck droplet and to measure the contact angle through an angle telescope equipped with an annular protractor.

Weathering chambers include Cleveland Condensing Cabinet (CCC) and QUV Tester (The Q-Panel Company, Cleveland, OH). The CCC chamber is operated at a vapor temperature of 140 ° F. (approx. 60 ° C.) in a room ambient environment, causing constant moisture condensation on the test surface. The QUV tester is run in cycles of 8 hours at 50 ° C. and condensation humidity using UV (one of the B313 or FS40 lamps) at a black panel temperature of 65-70 ° C.

The invention will be further understood from the description of the specific examples which follow.

Example 1

40 g trichlorotrifluoroethane (Freon A solution was prepared by mixing 1 g tetrachlorosilane and 1 g perfluoroalkyl alkylsilane) in a solvent, from DuPont. Perfluoroalkylalkylsilanes consisted of perfluoroalkylethyltrichlorosilanes, and the perfluoroalkyl moieties consisted mainly of C ₆ F ₁₃ to C ₁₈ F ₃₇ . For control, the control solution was mixed without using tetrachlorosilane. The solution was cleaned using a cotton pad ) Was applied to the atmospheric surface of floating glass (PPG Industries, Inc.). Coupons were cured at 200 ° F. (93 ° C.) for 1 hour. Excess silane was removed from the glass surface by solvent washing. Coupons were weathered in CCC and QUV-FS40 weathering cabinets. Coating efficiency was measured by the contact angle of the stuck water drops. The results are shown in the table below.

Example 2

Four solutions each were prepared from a mixture of 0.5% by weight perfluorohexylethyltrichlorosilane, 0.5% by weight alkane in an IsoPa L solution (exon). The solutions were tetrachlorosilane concentrations of 0.0, 0.2, 0.45 and 0.79 wt%. In order to utilize the reactive drying of the solvent with hydrolyzable tetrachlorosilane, the order of addition was isopa L, tetrachlorosilane and perfluoroalkylethyltrichlorosilane. These four solutions were coated onto the tin surface of a 0.182 inch (4.6 mm) thick clear floating glass coupon. Samples were tested in a CCC chamber. Coating efficiency was measured by the contact angle of the stuck water drops. In the table below it can be seen that increasing the concentration of hydrolyzable silane within this range improves the durability of the perfluoroalkylalkylsilane surface treatment.

Example 3

Fluorinert Four solutions each were prepared with 2.5% by weight perfluoroalkylethyltrichlorosilane and 2.5% by weight perfluoroalkylethylene as described in Example 1 in FC-77 solvent (3M product). The solution was 0.0, 1.0, 2.0 and 5.0 wt% tetrachlorosilane concentrations. These four solutions were coated onto the tin surface of a 0.187 inch (4.7 mm) thick clear floating glass coupon. Coupons were cured at 300 ° F. (149 ° C.) for 15 minutes. Samples were tested in CCC and QUVB-313 chambers. Coating efficiency was measured by the contact angle of the stuck water drops. The results are shown in the table below.

Example 4

Solutions containing 0.5% by weight perfluoroalkylethyltrichlorosilane and 0.5% by weight tetrachlorosilane and only 0.5% by weight perfluoroalkylethyltrichlorosilane in an isopa L solvent were prepared. Three perfluoroalkylethyltrichlorosilanes were used: 1H, 1H, 2H, 2H-tridecafluorooctyltrichlorosilane (octyl), 1H, 1H, 2H, 2H-heptandecafluorodecyl Trichlorosilane (decyl), or a mixture of perfluoroalkylethyltrichlorosilanes described in Example 1. Additive mixed Solex glass coupons and clean floating glass coupons that were subjected to heat treatment to test the bending cycle (without significant bending) were used for this study. Solex glass is 0.157 inch (4 mm) thick, clean floating glass is 0.090 inch (2.3 mm) thick, and tinned. Samples were tested on a QUVB-313 chamber and a wet sled wearer (Wet Sled Abrader, Sheen Instruments LTD, Model 903). Wet sled wearers are typically deformed using aluminum blocks that hold two automotive front windshield wiper blades. The wet sled wear test arranged as above rarely has high pressure wiper arm loading and is performed in partial wetting and partial drying. These wiper strokes are much worse than those typically used in automobiles. Coating efficiency was measured by the contact angle of the adhered droplets. + Means the presence of tetrachlorosilane in the coating formulation of the table below.

* These data (200-600 cycles) are based on 0.5-wt% Hi-Sil in water 233) obtained using a slurry of synthetic precipitated silica. 5000 cycles of data were obtained using only deionized water.

Example 5

A control solution was prepared by mixing 95 g FC-77 solvent, 2.5 g perfluoroalkylethyltrichlorosilane (perfluoroalkyl = C ₆ F ₁₃ -C ₁₈ F ₃₇ ) and 2.5 g perfluoroalkylethylene. 188g FC-77 solvent, 5g perfluoroalkylethyltrichlorosilane, 5.0g perfluoroalkylethylene (perfluoroalkyl = C ₆ F ₁₃ ~ C ₁₈ F ₃₇ ), 2g tetrachlorosilane mixed to contain a primer The solution was prepared. A solution of primer only was prepared from 198.4 g FC-77 solvent and 1.6 g tetrachlorosilane. This solution was applied to the tin surface of a 4.9 mm thick clear floating glass using a cotton pad. The selected coupons were coated with a primer solution prior to coating using a control or control solution containing perfluoroalkylalkylsilane and tetrachlorosilane. Coupons were cured at 300 ° F. (149 ° C.) for 15 minutes. Excess silane was removed from the glass surface by solvent washing. Coupons were weathered at CCC. Coating efficiency was measured by the contact angle of the stuck water drops.

Solutions containing silanes that can hydrolyze into silica produced more durable coatings regardless of whether the glass may be prepared as a layer of silica separately from the hydrolyzable silane solution.

The above examples are presented to illustrate the present invention. Various perfluoroalkylalkylsilanes, hydrolyzable silanes, solvents and concentrations can be used in any conventional manner and, when optimally cured at the appropriate temperature for a suitable time, can be used in many glass and plastic substrates as well as metals, ceramics, enamels and It provides a durable waterproof surface to other inorganic surfaces such as metal or metal oxide films. Treated substrates of the present invention are particularly suitable in automotive and aircraft parts as well as building components, lenses and CRT plates.

Claims (20)

Formula R _m R ' _n SiX _4-mn wherein R is a perfluoroalkylalkyl radical, R' is a vinyl or alkyl radical, m is 1, 2 or 3, n is 0, 1 or 2 , a sum of m and n is less than 4 and X is selected from the group consisting of halogen and acyloxy radicals) perfluoroalkylalkylsilanes; And a mixture of a siloxane capable of hydrolyzing with silica gel and a compound selected from the group consisting of a mixture of siloxanes and silanes. The composition of claim 1, wherein the perfluoroalkyl portion of the perfluoroalkylalkyl radical is selected from CF ₃ -C ₃₀ F ₆₁ . The composition of claim 1 wherein R 'is selected from the group consisting of methyl, ethyl, vinyl and propyl. The composition of claim 1 wherein X is selected from the group consisting of chloro, bromo, iodine and acetoxy. The composition of claim 1 wherein said perfluoroalkylalkylsilane is selected from the group consisting of perfluoroalkylethyltrichlorosilane, perfluoroalkylethyltriacetoxysilane, and perfluoroalkylethyldichloro (methyl) silane. . The composition of claim 1, wherein the silane capable of hydrolyzing into silica gel has a general formula SiX ₄ , wherein X is selected from the group consisting of halogen, alkoxy and acyloxy radicals. Formula R _m R ' _n SiX _4-mn wherein R is a perfluoroalkylalkyl radical, R' is a vinyl or alkyl radical, m is 1, 2 or 3, n is 0, 1 or 2 , a sum of m and n is less than 4 and X is selected from the group consisting of halogen, alkoxy and acyloxy radicals) perfluoroalkylalkylsilanes; And a mixture of a siloxane capable of hydrolyzing with silica gel and a mixture of siloxanes and silanes of the general formula SiX ₄ , wherein X is halogen. 8. The composition of claim 7, wherein the silane capable of hydrolysis with silica gel is silicon tetrachloride. The method of claim 1, wherein the siloxane capable of hydrolyzing with silica gel is a general formula Si _y O _z X _4y-2z (wherein X is selected from the group of halogen, alkoxy and acyloxy radicals, y is at least 2, z is at least 1 and 4y-2z is at least 0). Formula R _m R ' _n SiX _4-mn wherein R is a perfluoroalkylalkyl radical, R' is a vinyl or alkyl radical, m is 1, 2 or 3, n is 0, 1 or 2 , a sum of m and n is less than 4 and X is selected from the group consisting of halogen, alkoxy and acyloxy radicals) perfluoroalkylalkylsilanes; And a siloxane capable of hydrolyzing with silica gel and a mixture of siloxanes and silanes; And a mixture of fluorinated olefin telomers of the general formula C _m F _{2m + 1} CH═CH ₂ , wherein m is 1 to 30. 18. The mixture of claim 1 wherein said mixture of silanes hydrolyzable to perfluoroalkylalkylsilane and silica gel consists of alkanes, inorganic alcohols, acetone, toluene, naphtha, halogenated hydrocarbons, perfluorinated organic solvents and mixtures thereof A composition present in a solvent selected from the group. The composition of claim 11, wherein the perfluoroalkyl moiety of the perfluoroalkylalkyl compound is selected from CF ₃ -C ₃₀ F ₆₁ . 12. The composition of claim 11, wherein R 'is selected from the group consisting of methyl, ethyl, vinyl and propyl. 12. The composition of claim 11 wherein X is selected from the group consisting of chloro, bromo, iodo and acetoxy. The composition of claim 11 wherein said solvent is selected from the group consisting of hexane, heptane, inorganic alcohols, acetone, toluene, naphtha, trichlorotrifluoroethane, methylene chloride, perfluorocarbon and mixtures thereof. 12. The composition of claim 11 wherein said silane capable of hydrolysis with silica gel has the general formula SiX ₄ , wherein X is selected from the group consisting of halogen, alkoxy and acyloxy radicals. 17. The composition of claim 16, wherein said silane capable of hydrolysis with silica gel is silicon tetrachloride. The composition of claim 11, further comprising a fluorinated olefin telomer of general formula C _m F _{2m + 1} CH═CH ₂ , wherein m is 1-30. The composition of claim 1 wherein the mixture consists essentially of a compound selected from the group consisting of perfluoroalkylalkylsilanes and silanes and siloxanes. The composition of claim 1 wherein the mixture consists essentially of a compound selected from the group consisting of perfluoroalkylalkylsilanes and silanes and siloxanes in a solvent.