JPH08333545A - Water-repellent surface treatment integrated with priming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a substrate surface having large water repellency and large lubricity.

SOLUTION: This compsn. for forming a water-repellent surface on a substrate comprises a mixture of a perfluoroalkylalkylsilane selected from compds. represented by the formula R_mR'_nSiX_4-m-n (wherein R represents a perfluoroalkylalkyl group; R' represents a vinyl or alkyl group; m is 1, 2 or 3; n is 0, 1 or 2; m+n is less than 4; and X is selected from a group consisting of halogens and acyloxy groups) with a compd., hydrolyzable to silica gel, selected from a group consisting of silane and siloxane.

COPYRIGHT: (C)1996,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates generally to surface treatment techniques, and more particularly to techniques for forming water repellent surfaces on various substrates, and more particularly to improving the durability of such water repellent surfaces.

[0002]

U.S. Pat. No. 5,314,731 to Yoneda et al. Describes a surface treated substrate having at least two treated surface layers,
In this case the outermost first layer is obtained by treatment with a compound having at least one Si-NCO group capable of forming a surface having a contact angle with water of at least 70 °, The second layer of is obtained by treating with at least one reactive silane compound selected from an isocyanate silane compound and a hydrolyzable silane compound.

US Pat. Nos. 4,983,459 and 4,997,684 to Franz et al. Show durability on glass by treatment with perfluoroalkylalkylsilanes and fluorinated olefin telomers. Methods and articles for providing non-wettable surfaces, respectively, are described.

US Patent No. 5,30 to Franz et al.
No. 8,705 describes treating non-glass substrates with non-wettable surface properties by treatment with perfluoroalkylalkylsilanes and fluorinated olefin telomers.

US Pat. No. 5,328,768 to Goodwin describes a glass substrate having a surface first treated with a silica subbing layer and secondly a perfluoroalkylalkylsilane. There is.

[0006]

The present invention provides a substrate surface having great water repellency and great lubricity.

[0007]

The water and dirt repellency durability of a substrate surface is improved by applying a perfluoroalkylalkylsilane compound and a hydrolyzable silane or siloxane compound to the substrate surface. .
Hydrolyzable silane or siloxane compounds are compounds that can be hydrolytically condensed to form silica gel and serve as an integral basecoat compound. The surface treatment of the present invention can increase the durability of water repellent and soil repellent surfaces without the need for a separate undercoat layer. Greater water repellency and lubricity are provided by perfluoroalkylalkylsilanes. Hydrolyzable silanes or siloxanes also provide reactive drying of the solvent. Surface treatment with the perfluoroalkylalkylsilanes and hydrolyzable silanes or siloxanes of the present invention improves the abrasion resistance of the substrate surface. Silane or siloxane compounds that can be hydrolytically condensed to silica gel provide increased resistance to moisture, ultraviolet light, and mechanical abrasion.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The durability of rain and dirt repellency imparted by applying a perfluoroalkylalkylsilane to the surface of a substrate is silane, siloxane, or silane and / or silane that can be hydrolyzed to silica gel.
The mixture of siloxane compounds is increased by mixing with the perfluoroalkylalkylsilane prior to application.
According to the invention, by applying to the glass surface a mixture of a perfluoroalkylalkylsilane and a silane, siloxane, or a mixture of silane and / or siloxane compounds that can be hydrolyzed to silica gel,
More durable coatings can be formed than those formed without silanes, siloxanes, or mixtures of silane and / or siloxane compounds that can be hydrolyzed to silica gel.

The perfluoroalkylalkylsilane and the hydrolyzable silane and / or siloxane are preferably applied to the surface of the substrate as a colloidal suspension or solution to form the article of the invention, preferably in an aprotic solvent,
It is preferably applied as an alkane or mixture of alkanes, or in a fluorinated solvent. The preferred solution of the present invention may be applied to the substrate surface by any conventional method such as dipping, flushing, wiping or spraying. The silane reacts with the substrate surface, removing excess solution and providing a durable non-wetting lubricious surface with improved wear resistance. The present invention provides the durability benefits of subbing layers without the additional step of applying a separate subbing layer. By using fully hydrolyzable silanes and / or siloxanes, Cleveland Condensing Cabint QUV (F
With S40 or B313 lamps)
The silane surface treatment improved resistance to moisture, UV light, and abrasion, and wet sliding abrasion tests showed that the product had a longer useful life.

Suitable silanes that can be hydrolyzed to silica gel have the general formula SiX ₄ (where X is a halogen,
A hydrolyzable group generally selected from the group consisting of alkoxy and acyloxy groups).

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

Suitable siloxanes have the general formula Si _y O _z
X _4y-2z (wherein X is selected from the group consisting of halogen, alkoxy, and acyloxy groups, y is 2 or more,
z is 1 or more and 4y-2z is larger than 0). Preferred hydrolyzable siloxanes include hexachlorodisiloxane, octachlorotrisiloxane, and higher oligomeric chlorosiloxanes.

The hydrolyzable silane or siloxane serves two functions. One becomes part of the coating and provides weathering and abrasion resistance. Another function is to dry the solvent. A typical hydrocarbon solvent contains 50-200 ppm water. Other solvents may have a much higher water content. For example, a solvent containing 200 ppm water has sufficient water present to partially hydrolyze the perfluoroalkylalkylsilane at a concentration of 0.5% by weight. The fully hydrolyzable silane or siloxane can remove or reduce the water contained in the solvent prior to adding the perfluoroalkylalkylsilane. Otherwise, partially hydrolyzed perfluoroalkylalkylsilanes would result in poor coating adhesion or very low durability.

Preferred perfluoroalkyl alkyl silanes have the general formula _{R m R 'n SiX 4- mn} ( In the formulas, R represents a perfluoroalkyl group; m is typically 1, n is typically 0 or 1 and m + n is 4
Smaller; R'is a vinyl or alkyl group, preferably methyl, ethyl, vinyl, or propyl;
X is preferably a group such as halogen, acyloxy, and / or alkoxy). Perfluoroalkyl moiety preferred in perfluoroalkyl alkyl groups, CF ₃ ~C ₃₀ F _61, preferably C ₆ F ₁₃ ~C ₁₈ F
₃₇ , most preferably in the range C ₈ F _{17 to} C ₁₂ F ₂₅ ;
The alkyl moiety is preferably ethyl. R'is preferably methyl or ethyl. Preferred groups for X include hydrolyzable chloro, bromo, iodo, methoxy, ethoxy, and acetoxy groups. Preferred perfluoroalkylalkylsilanes according to the invention include perfluoroalkylethyltrichlorosilane, perfluoroalkylethyltrimethoxysilane, perfluoroalkylethyltriacetoxysilane, perfluoroalkylethyldichloro (methyl) silane, and perfluoroalkylethyldiethoxy (methyl) silane. Is included.

These preferred perfluoroalkylethylsilanes appear to react at the molecular level with the bonding sites on the substrate surface. The strong surface bonding of the perfluoroalkylethylsilane results in a durable substrate surface that exhibits a large contact angle with water droplets, which is highly water repellent.

Suitable solvents include hexane, heptane, mineral spirits, acetone, toluene, and naphtha. Preferred solvents are alkanes or trichlorotrifluoroethane, and halogenated hydrocarbons such as methylene chloride, and perfluorinated organic compounds such as perfluorocarbons. The concentration of silane is about 0.005-5
It is preferably 0, preferably about 0.05-5%.
The solvent may be evaporated by simple drying in air at ambient temperature, or excess solution may be preferably removed by wiping.

The silane may be crosslinked to form a more durable coating. Curing is preferably accomplished by heating the silanized surface. Typically at least about 66 ° C (150 ° F), especially about 93 ° C (200 ° F)
Higher cure temperatures are preferred. About 93 ° C (about 200 °
A curing step of about 30 minutes in F) is suitable. Higher temperatures and shorter heating times may be even more effective.
A curing step of 2-5 minutes at about 204-260 ° C (400-500 ° F) is preferred, especially about 243 ° C (about 470 ° C).
It is preferably about 3 minutes in F). The fluorinated olefin telomer may be included in the silane composition described in US Pat. No. 5,308,705 and preferably has the general formula C _m F _{2m + 1} CH═CH ₂ (formula Where m is 1 to 30, preferably 1 to 16, and more preferably 4 to 10). Alternatively, the substrate surface may be contacted with a vaporized perfluoroalkylalkylsilane.

The contact angles referred to herein are Gaertner Scientific Goniometer opts.
ics) equipped with Road Manufacturing (Lord
Measured by the static drop method using a modified static bubble indicator manufactured by Manufacturing Inc.). The surface to be measured is placed horizontally in front of the light source, facing upwards. A drop of water can be placed on the surface in front of the light source, the profile of the stationary drop can be seen and the contact angle can be measured through a goniometer telescope equipped with a protractor.

The weathering test chamber consists of a Cleveland Condensing Cabinet (CCC) and a QUV tester (Q-Panel C of Cleveland, Ohio).
o.) products]. The CCC chamber operated at a steam temperature of 60 ° C (140 ° F) in an indoor environment, which caused constant water condensation on the test surface. QUV tester is 65
UV (B313 or FS) for 8 hours at black plate temperature of ~ 70 ° C
40 lamps) and operated in a cycle of moisture condensation at 50 ° C. for 4 hours.

[0020]

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

Example 1 1 g of tetrachlorosilane and 1 g of perfluoroalkane
40 g of trialkyltrifluoro of alkylalkylsilane
Ethane (Freon, a DuPont product)
[Namely) TF solvent]
Was prepared. Perfluoroalkylalkylsilane is
Perfluoroalkyl moiety is mainly C₆F ₁₃~ C₁₈F₃₇Or
Perfluoroalkylethyltrichlorosilane consisting of
It was Including tetrachlorosilane for comparison
No control solution was mixed. 3.9 mm of those solutions
Thick Solex® Float Glass
Of PPG Industries, Inc.
The product] was applied to the surface of the atmosphere side with a cotton pad. Try them
The material was cured at 93 ° C (200 ° F) for 1 hour. Excessive si
The orchid was removed from the glass surface by solvent washing. Those
CCC and QUV-FS40 weather resistance test
It was subjected to a weather resistance test on the net. Coating effect, static liquid
It was measured by the contact angle of the drop. The results are shown in the table below.

[0022]

TABLE 1 TABLE 1 CCC QUV-FS40 hours without primer primer time without primer undercoating agent 0 105 ° 105 ° 0 107 ° 106 ° 496 102 ° 87 ° 319 106 ° 102 ° 927 67 ° 60 ° 1332 91 ° 89 ° 1669 49 ° 40 ° 2115 83 ° 79 ° 2498 78 ° 70 ° 2943 72 ° 57 °

Example 2 0.5% by weight of perfluorohexylethyltrichlorosilane, respectively, isopal (I), which is a mixture of alkanes.
sopar) L solvent (product of Exxon) was prepared in 4 different solutions. The solutions were 0.0, 0.
It had a concentration of tetrachlorosilane of 2, 0.45, and 0.79% by weight. The order of addition was Isopar L, tetrachlorosilane, and perfluoroalkylethyltrichlorosilane, utilizing reactive drying of the solvent with hydrolyzable tetrachlorosilane. These four solutions were coated on the tin side surface of a 4.6 mm (0.182 in) thick transparent float glass sample. The samples were tested in the CCC room. The coating effect was measured by the contact angle of a static water drop. From the following table it can be seen that increasing the concentration of hydrolyzable silane within this range improves the durability of the perfluoroalkylalkylsilane surface treatment.

[0024]

[Table 2] Table 2 CCC contact angle (°) Undercoat concentration (wt%) Time 0 0.2 0.45 0.79 0 115 115 114 114 122 81 89 105 105 284 54 65 77 81 475 36 44 58 69 642 ----- -47

Example 3 Fluorinert containing 2.5% by weight of the perfluoroalkylethyltrichlorosilane described in Example 1 and 2.5% by weight of perfluoroalkylethylene, respectively.
Four solutions were prepared in (registered trade name) FC-77 solvent (3M product). The solutions had tetrachlorosilane concentrations of 0.0, 1.0, 2.0, and 5.0% by weight. These four solutions were coated on the tin side surface of a 4.7 mm (0.187 in) thick transparent float glass sample. The samples were cured at 149 ° C (300 ° F) for 15 minutes. The samples were tested in the CCC and QUVB-313 chambers. The coating efficiency was measured by the contact angle of a static water drop. The results are shown in the table below.

[0026]

[Table 3] Table 3A CCC contact angle (°) Undercoating agent concentration (wt%) Time 0 1.0 2.0 5.0 0 113 113 115 114 162 95 109 114 112 348 73 81 98 93 684 31 41 43 34 Table 3B QUVB-313 contact Angle (°) Undercoat concentration (wt%) Time 0 1.0 2.0 5.0 0 113 114 117 116 566 107 111 111 109 1375 82 95 95 87 2095 72 80 84 71

Example 4 A solution of 0.5 wt% perfluoroalkylethyltrichlorosilane in Isopar L solvent was prepared with and without 0.5 wt% tetrachlorosilane. Three types of perfluoroalkylethyltrichlorosilanes: 1H, 1H, 2H, 2H-tridecafluorooctyltrichlorosilane ("octyl");
1H, 1H, 2H, 2H-heptadecafluorodecyltrichlorosilane ("decyl"); or a mixture of perfluoroalkylethyltrichlorosilanes as described in Example 1;
Was used. A tempered Solex (R) glass sample and a clear float glass sample that was subjected to a heat treatment similar to the flex cycle (less flex) were used in this study. Solex glass has a thickness of 4 mm (0.157 in) and transparent float glass has a thickness of 2.3 mm (0.090 i).
n) thick and treated tin side surface. QU those samples
VB-313 Chamber and Wet Sliding Abrasion Tester [Sheen Instruments LTD, Model 903]
Tested. The wet sliding wear tester was specially modified with an aluminum block that holds two automotive windshield wiper blades. The wet sliding wear test thus constructed was carried out by applying a load by a wiper arm having an abnormally large pressure and partially wet and partially dry. The strokes of these wipers were far more severe than those normally used in vehicles. The coating effect was measured by the contact angle of a static water drop. The "+" symbol in the following table indicates the presence of tetrachlorosilane in the coating formulation.

[0028]

Table 4 Table 4A QUVB-313 Contact angle (°) Time octyl octyl + decyl decyl + mix mixture + 0 116 112 111 115 111 118 163 102 105 87 112 102 116 352 95 95 84 107 100 111 496 82 88 74 102 89 106 659 79 80 66 93 82 99 827 70 85 60 89 82 103 table 4B wet skid abrasion test contact angle (°) cycles octyl octyl + decyl decyl + mix mixture + 0 113 117 111 116 115 117 200 ★ 86 104 79 108 86 108 600 ★ 52 99 78 106 79 105 5000 35 84 47 91 82 92

★ These data (200 and 600
Cycle) is 0.5 wt% Hi-Sil
Obtained using a slurry of (registered trademark) 233 synthetic precipitated silica in water. Data for 5000 cycles were obtained using only deionized water.

Example 5 The control solution was mixed with 95 g of FC-77 solvent, 2.5 g of perfluoroalkylethyltrichlorosilane (perfluoroalkyl = C ₆ F _{13 to} C ₁₈ F ₃₇ ), and 2.5 g of perfluoroalkylethylene. Was prepared by The undercoating agent-containing solution was mixed with 188 g of FC-77 solvent, 5 g of perfluoroalkylethyltrichlorosilane, 5.0 g of perfluoroalkylethylene (perfluoroalkyl = C ₆ F _{13 to} C ₁₈ F ₃₇ ), and 2 g of tetrachlorosilane. Was prepared by A primer only solution was prepared from 198.4 g FC-77 solvent and 1.6 g tetrachlorosilane. These solutions were applied with a cotton pad to the tin side surface of 4.9 mm thick clear float glass. Selected samples were coated with a primer solution followed by a control solution or a solution containing perfluoroalkylalkylsilane and tetrachlorosilane. The sample was cured at 149 ° C (300 ° F) for 15 minutes. Excess silane was removed from the glass surface by solvent washing. The samples were weathered in CCC. The coating effect was measured by the contact angle of a static water drop.

[0031]

[Table 5] Table 5 CCC contact angle (° C) Without undercoat layer With undercoat layer Time Integrated undercoat Integrated undercoat Integrated undercoat Integrated undercoat Ri agents without Ri agents there Ri agents without Ri agents there 0 114 114 113 114 232 116 116 117 115 398 100 110 109 110 590 49 78 75 86 918 29 39 31 41

The solution containing the silane hydrolyzable to silica provides a more durable coating whether or not the glass has been previously primed with a layer of silica by another hydrolyzable silane solution.

The above examples are provided to illustrate the present invention. By applying various perfluoroalkylalkylsilanes, hydrolyzable silanes, and solvents at various concentrations by conventional methods and curing at any suitable temperature for a suitable temperature, in addition to various glass and plastic substrates, metal It can provide a durable, non-wettable surface to any of other inorganic surfaces such as, ceramics, enamel, and metals, or metal oxide films.
The treated substrates of the present invention are particularly suitable for automotive and aircraft parts, as well as building parts, lenses and CRT boards.

Claims (23)

[Claims] 1. A general formula R _m R ′ _n SiX _4-mn (wherein
R is a perfluoroalkylalkyl group, R'is a vinyl or alkyl group, m is 1, 2, or 3, n is 0, 1, or 2, m + n is less than 4, and X is a halogen. And a perfluoroalkylalkylsilane selected from compounds having an acyloxy group) and a compound selected from the group consisting of silanes and siloxanes that can be hydrolyzed to silica gel. , A composition for forming a water-repellent surface on a substrate. 2. The composition of claim 1, wherein the perfluoroalkyl portion of the perfluoroalkylalkyl group is selected from the group consisting of CF ₃ -C ₃₀ F ₆₁ . 3. The composition according to claim 1, wherein R'is selected from the group consisting of methyl, ethyl, vinyl, and propyl. 4. The composition of claim 1, wherein X is selected from the group consisting of chloro, bromo, iodo, and acetoxy. 5. The composition according to claim 1, wherein the perfluoroalkylalkylsilane is selected from the group consisting of perfluoroalkylethyltrichlorosilane, perfluoroalkylethyltriacetoxysilane, and perfluoroalkylethyldichloro (methyl) silane. . 6. A silane capable of being hydrolyzed to silica gel has the general formula SiX ₄ (where X is selected from the group consisting of halogen, alkoxy, and acyloxy groups).
The composition of claim 1, comprising: 7. A general formula R _m R ′ _n SiX _4-mn (wherein
R is a perfluoroalkylalkyl group, R'is a vinyl or alkyl group, m is 1, 2, or 3, n is 0, 1, or 2, m + n is less than 4, and X is a halogen. , An alkoxy, and an acyloxy group)), a perfluoroalkylalkylsilane selected from compounds having a general formula, S,
a silane having iX ₄ (wherein X is halogen),
A composition for forming a water repellent surface on a substrate, which comprises a mixture of 8. A composition according to claim 7, wherein the silane capable of being hydrolyzed to silica gel is silicon tetrachloride. 9. A siloxane capable of being hydrolyzed to silica gel is represented by the general formula: Si _y O _z X _4y-2z (wherein X
Is selected from the group consisting of halogen, alkoxy, and acyloxy groups, y is 2 or more, z is 1 or more,
4y-2z is greater than 0). 10. A compound represented by the general formula R _m R ′ _n SiX _4-mn (wherein R is a perfluoroalkylalkyl group, R ′
Is a vinyl or alkyl group, m is 1, 2, or 3, n is 0, 1, or 2, m + n is less than 4, and X is selected from the group consisting of halogen, alkoxy, and acyloxy groups. Selected from the group consisting of silanes and siloxanes capable of being hydrolyzed to silica gel with silanes and siloxanes, and compounds of the general formula C _m F _{2m + 1.} CH = CH ₂ (wherein, m is a is 1 to 30) consisting of a fluorinated olefin telomer, mixtures having the composition for forming a water-repellent surface on a substrate. 11. A mixture of perfluoroalkylalkylsilanes and silanes that can be hydrolyzed to silica gel from alkanes, mineral spirits, acetone, toluene, naphtha, halogenated hydrocarbons, perfluorinated organic solvents, and mixtures thereof. The composition of claim 1 in a solvent selected from the group consisting of: 12. The perfluoroalkyl portion of the perfluoroalkylalkyl group is CF ₃ -C ₃₀ F ₆₁ .
The composition according to claim 11. 13. R'is selected from the group consisting of methyl, ethyl, vinyl, and propyl.
The composition according to. 14. X is selected from the group consisting of chloro, bromo, iodo, and acetoxy.
The composition according to 1. 15. The solvent of claim 11, wherein the solvent is selected from the group consisting of hexane, heptane, mineral spirits, acetone, toluene, naphtha, trichlorotrifluoroethane, methylene chloride, perfluorocarbons, and mixtures thereof. Composition. 16. A silane capable of being hydrolyzed to silica gel has the general formula SiX ₄ (X is selected from the group consisting of halogen, alkoxy, and acyloxy groups).
13. The composition of claim 11, which comprises: 17. The composition of claim 16, wherein the silane that can be hydrolyzed to silica gel is silicon tetrachloride. 18. (wherein, m is a is 1 to 30) Formula _{C m F 2m + 1 CH =} CH 2 , further comprising a fluorinated olefin telomer having the composition of claim 11. 19. The composition of claim 1, wherein the mixture consists essentially of perfluoroalkylalkylsilane and compound. 20. The composition of claim 1, wherein the mixture consists essentially of the perfluoroalkylalkylsilane and the compound in a solvent. The method according to claim 21 The substrate in the method of coating with water-repellent coating, general formula _{R m R 'n SiX 4-} mn ( wherein, R is a perfluoroalkyl an alkyl group, R' is an a vinyl or an alkyl group, m is 1, 2, or 3, n is 0, 1,
Or 2, m + n is less than 4, X is halogen,
A composition comprising a perfluoroalkylalkylsilane selected from the group consisting of alkoxy and acyloxy groups) and a compound selected from the group consisting of silanes and siloxanes that can be hydrolyzed to silica gel. And applying the composition to the surface of the substrate, where the surface of the substrate is rubbed with the composition and the contact angle is at least 100 ° during the rubbing step within 1 hour. A method for coating a substrate comprising the steps of: providing a water-repellent surface having a surface of the substrate, and then removing excess composition from the substrate surface. 22. The method of claim 21, further comprising heating the surface of the substrate after performing the removing step. 23. The step of providing a composition comprises the step of providing, in a solvent, a mixture of a perfluoroalkylalkylsilane and a compound selected from the group consisting of silanes and siloxanes that can be hydrolyzed to silica gel. The method of claim 21.