Fluorochemical coating composition and article treated therewith

Abstract

A fluorochemical coating composition is provided comprising (A) a hydrolyzable group-containing silane modified with a fluoropolyether-containing polymer and (B) a hydrolyzable group-containing silane modified with a fluoropolyether-polysiloxane copolymer in a weight ratio (A)/(B) of 40/60 to 95/5. The composition forms on a substrate a water/oil repellent layer which does not detract from the visibility of the substrate.

Claims

1. A fluorochemical coating composition comprising (A) a hydrolyzable group-containing silane modified with a fluoropolyether-containing polymer and/or a partial hydrolytic condensate thereof, and (B) a hydrolyzable group-containing silane modified with a fluoropolyether-polysiloxane copolymer and/or a partial hydrolytic condensate thereof, in a weight ratio (A)/(B) of 40/60 to 95/5.

2. The fluorochemical coating composition of claim 1 wherein component (A) contains 10 to 200 repeating units of the general formula (1):
C.sub.gF.sub.2gO-(1) wherein g is independently in each unit an integer of 1 to 6, as the fluoropolyether group, and has at least one hydrolyzable silyl group of the general formula (2): ##STR00037## wherein R is C.sub.1-C.sub.4 alkyl or phenyl, X is a hydrolyzable group, and a is 2 or 3, at one or more ends, and component (B) contains 10 to 200 repeating units of the general formula (1) as the fluoropolyether portion, and 3 to 200 siloxane bonds as the polysiloxane portion.

3. The fluorochemical coating composition of claim 1 wherein the hydrolyzable group-containing silane modified with a fluoropolyether-containing polymer (A) is at least one member selected from fluoropolyether-containing polymer-modified silanes having the general formulae (3), (4), (5) and (6):
A-Rf-QZ(W).sub.(3)
Rf-(QZ(W).sub.).sub.2(4)
A-Rf-Q-(Y).sub.B(5)
Rf-(Q-(Y).sub.B).sub.2(6) wherein Rf is (CF.sub.2).sub.dO(CF.sub.2O).sub.p(CF.sub.2CF.sub.2O).sub.q(CF.sub.2CF.sub.2CF.sub.2O).sub.r(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.s(CF(CF.sub.3)CF.sub.2O).sub.t(CF.sub.2).sub.d, d is independently an integer of 0 to 5, p, q, r, s and t are each independently an integer of 0 to 200, p+q+r+s+t is an integer of 10 to 200, individual units in parentheses may be randomly arranged, A is fluorine, hydrogen, or a monovalent fluorinated group terminated with CF.sub.3, CF.sub.2H or CH.sub.2F radical, Q is a single bond or an optionally fluorinated divalent organic group, Z is a single bond, a trivalent group: -JC (wherein J is an alkyl, hydroxyl or silyl ether group: K.sub.3SiO wherein K is independently hydrogen, alkyl, aryl or alkoxy), a trivalent group: -LSi (wherein L is alkyl), a tetravalent group: C, a tetravalent group: Si, or a di- to octavalent siloxane residue, W is a hydrolyzable group-bearing group having the general formula (7): ##STR00038## wherein R is C.sub.1-C.sub.4 alkyl or phenyl, X is a hydrolyzable group, a is 2 or 3, and 1 is an integer of 0 to 10, is an integer of 1 to 7, Y is a hydrolyzable group-bearing divalent group having the general formula (8), (9), (10) or (10): ##STR00039## wherein R, X and a are as defined above, D is a single bond or an optionally fluorinated C.sub.1-C.sub.20 divalent organic group, D is an optionally fluorinated C.sub.1-C.sub.10 divalent organic group, R is a C.sub.1-C.sub.20 monovalent hydrocarbon group, R.sup.2 is hydrogen or methyl, and e is 1 or 2, is an integer of 1 to 10, and B is hydrogen, C.sub.1-C.sub.4 alkyl or halogen.

4. The fluorochemical coating composition of claim 1 wherein the hydrolyzable group-containing silane modified with a fluoropolyether-polysiloxane copolymer (B) is at least one member selected from fluoropolyether-polysiloxane copolymer-modified silanes having the general formulae (11) and (12):
A-Rf-QZW.sub.(11)
Rf-(QZW.sub.).sub.2(12) wherein Rf is a divalent group containing fluoropolyether-polysiloxane copolymer, A is fluorine, hydrogen, or a monovalent fluorinated group terminated with CF.sub.3, CF.sub.2H or CH.sub.2F radical, Q is a single bond or an optionally fluorinated divalent organic group, Z is a single bond, a trivalent group: -JC (wherein J is an alkyl, hydroxyl or silyl ether group: K.sub.3SiO wherein K is independently hydrogen, alkyl, aryl or alkoxy), a trivalent group: -LSi (wherein L is alkyl), a tetravalent group: C, a tetravalent group: Si, or a di- to octavalent siloxane residue, W is a hydrolyzable group-bearing group having the general formula (7): ##STR00040## wherein R is C.sub.1-C.sub.4 alkyl or phenyl, X is a hydrolyzable group, a is 2 or 3, and 1 is an integer of 0 to 10, and is an integer of 1 to 7.

5. The fluorochemical coating composition of claim 4 wherein Rf in formulae (11) and (12) is a group having the general formula (13) or (14):
(Z-Q).sub.h-Rf-(Q-Z).sub.h-(13)
Rf-(Q-Z-Q-Rf).sub.i-(14) wherein Q is as defined above, Rf is (CF.sub.2).sub.dO(CF.sub.2O).sub.p(CF.sub.2CF.sub.2O).sub.q(CF.sub.2CF.sub.2CF.sub.2O).sub.r(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.s(CF(CF.sub.3)CF.sub.2O).sub.t(CF.sub.2).sub.d, d is independently an integer of 0 to 5, p, q, r, s and t are each independently an integer of 0 to 200, p+q+r+s+t is an integer of 10 to 200, individual units in parentheses may be randomly arranged, Z is each independently a divalent polysiloxane chain, h is independently 0 or 1, and i is an integer of 1 to 3.

6. The fluorochemical coating composition of claim 5 wherein Z in formulae (13) and (14) is a polysiloxane chain having the general formula (15) or (16): ##STR00041## wherein R is each independently C.sub.1-C.sub.4 alkyl, phenyl or phenylethyl, j is an integer of 10 to 200, y is an integer of 1 to 5, u and v are each independently an integer of 1 to 200.

7. The fluorochemical coating composition of claim 1, further comprising (C) a fluoropolyether-containing polymer having the general formula (17):
A-Rf-A(17) wherein Rf is (CF.sub.2).sub.dO(CF.sub.2O).sub.p(CF.sub.2CF.sub.2O).sub.q(CF.sub.2CF.sub.2CF.sub.2O).sub.r(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.s(CF(CF.sub.3)CF.sub.2O).sub.t(CF.sub.2).sub.d, d is independently an integer of 0 to 5, p, q, r, s and t are each independently an integer of 0 to 200, p+q+r+s+t is an integer of 10 to 200, individual units in parentheses may be randomly arranged, and A is fluorine, hydrogen, or a monovalent fluorinated group terminated with CF.sub.3, CF.sub.2H or CH.sub.2F radical.

8. The fluorochemical coating composition of claim 1, further comprising a fluorochemical solvent.

9. An article treated with the fluorochemical coating composition of claim 1.

10. A touch panel treated with the fluorochemical coating composition of claim 1.

11. An antireflective coated article treated with the fluorochemical coating composition of claim 1.

12. A glass treated with the fluorochemical coating composition of claim 1.

13. A strengthened glass treated with the fluorochemical coating composition of claim 1.

14. A sapphire glass treated with the fluorochemical coating composition of claim 1.

15. A quartz glass treated with the fluorochemical coating composition of claim 1.

16. A SiO.sub.2-deposited substrate treated with the fluorochemical coating composition of claim 1.

Description

EXAMPLE

(1) Examples of the invention are given below by way of illustration and not by way of limitation.

(2) As the hydrolyzable group-containing silane modified with a fluoropolyether-containing polymer, there were furnished Compounds 1 to 3 shown below.

(3) ##STR00035##

(4) As the hydrolyzable group-containing silane modified with a fluoropolyether-polysiloxane copolymer, there were furnished Compounds 4 and 5 shown below.

(5) ##STR00036##
Preparation of Coating Composition and Formation of Cured Film

(6) Coating compositions were prepared by combining components (A) and (B) in the weight ratio shown in Table 1, dissolving them in solvent Novec 7200 (ethyl perfluorobutyl ether by 3M) in a solid concentration of 0.5 wt %. A glass plate (Gorilla II by Corning) was dipped in the coating composition bath for 60 seconds, pulled up at a rate of 300 mm/min, and held at 80 C. in an atmosphere of humidity 80% for 1 hour. In this way, the coating is cured into a cured film of about 20 nm thick, obtaining a test sample.

(7) TABLE-US-00001 TABLE 1 Component A Component B B/(A + B), wt % Example 1 Compound 1 Compound 4 30 2 Compound 2 Compound 4 30 3 Compound 3 Compound 4 30 4 Compound 2 Compound 5 5 5 Compound 2 Compound 5 10 6 Compound 2 Compound 5 20 7 Compound 2 Compound 5 40 8 Compound 2 Compound 5 50 9 Compound 3 Compound 4 50 Comparative 1 Compound 1 0 Example 2 Compound 2 0 3 Compound 3 0 4 Compound 2 Compound 5 70 5 Compound 2 Compound 5 2 6 Compound 5 100

(8) The sample (or cured film) was evaluated by the following tests. All the tests were performed at 25 C. and humidity 50%. The results are shown in Table 2.

(9) Water/Oil Repellency

(10) Using a contact angle meter Drop Master (Kyowa Interface Science Co., Ltd.), the cured film was measured for a contact angle with water (droplet: 2 l) as an index of water repellency and with oleic acid (droplet: 5 l) as an index of oil repellency.

(11) Haze

(12) Using a haze meter NDH-500 (Nippon Denshoku Co., Ltd.), the sample was measured for haze according to JIS K 7136.

(13) Dynamic Friction

(14) Using a surface property tester 14FW (Shinto Scientific Co., Ltd.), the sample was measured for a coefficient of dynamic friction relative to non-woven fabric Bemcot (Asahi Kasei Fibers Corp.) over a contact area of 10 mm35 mm and under a load of 200 g.

(15) Oil Wipe-Off

(16) On the sample surface, a droplet (5 l) of oleic acid was dropped. The sample surface was wiped 10 strokes with non-woven fabric Bemcot under a load of 250 g/cm.sup.2 before it was measured for haze. For the wiping operation, the surface property tester 14FW was used.

(17) TABLE-US-00002 TABLE 2 Contact Contact Coefficient Oil angle with angle with of dynamic wipe- water () oleic acid () Haze friction off Example 1 111 68 0.38 0.04 0.39 2 112 67 0.35 0.03 0.37 3 108 62 0.32 0.04 0.35 4 114 70 0.40 0.03 0.42 5 114 69 0.38 0.03 0.39 6 113 68 0.35 0.03 0.37 7 112 65 0.34 0.03 0.37 8 111 63 0.35 0.03 0.36 9 107 61 0.38 0.03 0.38 Compar- 1 115 72 0.88 0.28 0.55 ative 2 115 70 1.34 0.03 0.98 Example 3 108 68 1.55 0.09 0.74 4 110 59 0.35 0.03 0.55 5 115 70 0.52 0.03 0.42 6 107 59 0.28 0.03 0.58

(18) As is evident from the test results, the coating compositions of Comparative Examples 1 to 3 using component (A) alone showed a haze in excess of 5 as a result of polymer molecules agglomerating together, indicating a lack of visibility. The coating composition of Comparative Example 6 using component (B) alone showed insufficient oil wipe-off after the sample surface was stained with oleic acid.

(19) The coating compositions of Examples 1 to 9 in which component (B) was 5 to 50 wt % based on the weight of components (A) and (B) combined were effective for preventing polymer molecules from agglomerating together, and suppressing any haze increase.

(20) Although the coating compositions of Comparative Examples 1 and 3 using component (A) alone showed a high coefficient of dynamic friction, the coating compositions of Examples 1, 3 and 9 using a mixture of components (A) and (B) in a specific ratio showed a coefficient of dynamic friction of less than 0.05.

(21) The coating composition of Comparative Example 4 containing more than 60 wt % of component (B) showed a decline of contact angle with oleic acid below 60. The coating composition of Comparative Example 5 containing less than 5 wt % of component (B) failed to suppress a haze increase.

(22) It is demonstrated that the fluorochemical coating composition comprising the hydrolyzable group-containing silane modified with a fluoropolyether-containing polymer and/or a partial hydrolytic condensate thereof, and the hydrolyzable group-containing silane modified with a fluoropolyether-polysiloxane copolymer and/or a partial hydrolytic condensate thereof forms a cured film having water/oil repellency and a low haze. Therefore, the fluorochemical coating composition is advantageously applicable to touch panel displays, antireflective films and other articles which are expected to be stained with oils and fats and required to maintain visibility.

(23) Japanese Patent Application No. 2014-074094 is incorporated herein by reference.

(24) Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.