JP2002038094A - Super water-repellent coating and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide a base material having a contact angle of 140 ° on the surface.
The purpose of the present invention is to easily form the above-mentioned water-repellent film, that is, a super water-repellent film. According to the present invention, there is provided an organic-inorganic hybrid coating comprising a metal and / or metalloid alkoxide and an organosilicon compound on a substrate surface by a sol-gel method. A super-water-repellent coating in which solid lubricating particles are dispersed is formed on the coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a super water-repellent film produced by a sol-gel method and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a super water-repellent film formed by a sol-gel method, a metal oxide film in which a fluororesin powder is dispersed (Japanese Patent No. 2724802) and an oxide film composed of a metal alkoxide are used. Dispersion (JP-A-4-325446) and the like.

[0003]

The super water-repellent coating of the prior art described above has a contact angle with water (hereinafter simply referred to as a contact angle) of at most about 120 °. 1
A water-repellent coating having a temperature of 40 ° or more, that is, a so-called super water-repellent coating could not be obtained.

[0004]

According to the present invention, there is provided an organic-inorganic hybrid coating comprising a metal and / or metalloid alkoxide and an organosilicon compound by a sol-gel method. The coating is to provide a super water-repellent coating in which solid lubricating particles are dispersed.

The organosilicon compound is desirably silanol-terminated polydimethylsiloxane, and the solid lubricating particles are desirably polytetrafluoroethylene.

The contact angle of the super water repellent film with water is 140.
° or more.

It is useful that the super water-repellent coating is formed on a base material of a transfer fixing member for an electrophotographic apparatus.

Further, the present invention provides a means for solving the above-mentioned problem, in which a solid lubricating particle is dispersed in an organic / inorganic hybrid sol liquid comprising a metal and / or metalloid alkoxide and an organosilicon compound to prepare a coating liquid. A method for preparing a super-water-repellent coating comprising the above-mentioned steps: a coating liquid preparation step 1 for coating, a coating step 2 for coating the substrate with the coating liquid, and a heating step 3 for forming a super-water-repellent coating by heat treatment. Things.

In the above method for producing a super water-repellent coating, the organosilicon compound is desirably silanol-terminated polydimethylsiloxane, and the solid lubricating particles are desirably polytetrafluoroethylene.

[0010] The contact angle with water of the super water-repellent coating produced by the above production method is 140 ° or more.

[0011]

By dispersing solid lubricating particles in an organic / inorganic hybrid coating, the water repellency of the coating can be improved, and the coating becomes a super water-repellent coating.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The super-water-repellent coating of the present invention is an organic-inorganic hybrid coating composed of a metal and / or metalloid alkoxide and an organosilicon compound by a sol-gel method, wherein solid lubricating particles are dispersed in the coating. A coating liquid preparation step 1 in which solid lubricating particles are dispersed in an organic / inorganic hybrid sol liquid comprising a metal and / or metalloid alkoxide and an organosilicon compound to prepare a coating liquid; And a heating step 3 of forming a super water-repellent film by heat treatment.

[Step 1] In step 1, first, an organic / inorganic hybrid sol solution comprising a metal and / or metalloid alkoxide and an organosilicon compound is prepared.

The types of the metal or metalloid forming the alkoxide include aluminum, silicon, titanium,
Examples of the metal or metalloid capable of forming an alkoxide such as vanadium, manganese, iron, cobalt, zinc, germanium, yttrium, zirconium, niobium, cadmium, and tantalum.

The type of the alkoxide is not particularly limited, and examples thereof include methoxide, ethoxide, propoxide, isopropoxide, butoxide and the like. Further, part of the alkoxy group is β-diketone, β-ketoester. Or an alkoxide derivative substituted with an alkanolamine, an alkylalkanolamine or the like.

Examples of the organosilicon compound include, for example,
Dialkyl dialkoxysilane, terminal silanol polydimethylsiloxane and the like can be used. Examples of the dialkyldialkoxysilane include, for example, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, dipropyl Examples include dimethoxysilane, dipropyldiethoxysilane, dipropyldipropoxysilane, dipropyldibutoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldipropoxysilane, diphenyldibutoxysilane, and the like. The terminal silanol polydimethylsiloxane preferably has a weight average molecular weight of 400 to 10,000. Examples of the fluorine-substituted organosilicon compound include those obtained by substituting hydrogen of the above-mentioned organosilicon compound with fluorine. Such compounds include, for example,
_{CF 3 CH 2 CH 2 -Si (} OC 2 H 5) 3 and the like.

The hydrolyzate of the metal and / or metalloid alkoxide is reacted with an organic component such as the organosilicon compound to prepare an organic / inorganic hybrid sol solution. The organic component may be mixed with the alkoxide before hydrolysis or with the hydrolyzed alkoxide.

The solvent used at this time is not particularly limited as long as it is a solvent capable of uniformly dispersing and dissolving the alkoxide and the organic component. Examples thereof include various alcohols such as methanol and ethanol, as well as acetone, toluene and xylene. Etc. are commonly used. In order to accelerate the hydrolysis reaction of the alkoxide, a catalyst such as hydrochloric acid, phosphoric acid, and acetic acid may be appropriately used.

When dialkylalkoxysilane is used as the organic component, the mixing ratio with the alkoxide as the inorganic component is such that the molar ratio of organic component / (organic component + inorganic component) is 0.5 to 0.95. It is preferred that
If the molar ratio is less than 0.5, the resulting coating may peel off or crack, and the molar ratio may be 0.9.
If it exceeds 5, the surface hardness of the resulting coating may be significantly reduced.

When the silanol-terminated polydimethylsiloxane is used as the organic component, the mixing ratio with the alkoxide as the inorganic component is as follows: organic component / (organic component +
The molar ratio of the (inorganic component) is preferably in the range of 0.1 to 0.7. If the molar ratio is less than 0.1, the resulting coating may be hard and brittle, and may not be elastically deformed.
If the molar ratio exceeds 0.7, the reaction product of the organic component and the inorganic component may not gel.

When the terminal silanol polydimethylsiloxane is reacted with the alkoxide, the alkoxy group of the alkoxide is replaced by a hydroxyl group, and the hydroxyl group undergoes a dehydration / condensation reaction with the terminal silanol group of the terminal silanol polydimethylsiloxane. An elastomer is formed.

The organic / inorganic hybrid sol liquid sufficiently hydrolyzes the alkoxide by stirring or the like and partially performs dehydration polymerization.

The organic / inorganic hybrid sol obtained as described above is further mixed with solid lubricating particles to prepare a coating liquid in which the solid lubricating particles are dispersed.

The solid lubricating particles are particles added to an organic / inorganic hybrid sol solution to impart super-water repellency to the organic / inorganic hybrid coating, and include polytetrafluoroethylene, tetrafluoroethylene and hexafluoropropylene. And powders of fluororesins such as polytrifluorochloroethylene and polyvinylidene, oxide powders such as silicon oxide, aluminum oxide, titanium oxide and zirconium oxide, graphite powders, and stearic acid and siloxane. The above-mentioned oxide powder, metal powder, metal salt powder, and the like, which have been surface-treated with a lubricant, are given as examples. The average particle size of the solid lubricating particles is 0.005.
It is preferably in the range of ２０20 μm. The addition amount of the solid lubricating particles is preferably in the range of 1 to 90% by volume based on the organic / inorganic hybrid sol liquid.

Organic / inorganic to which the solid lubricating particles are added
The hybrid sol liquid is stirred by a desired stirring device, and the solid
Body lubricating particles are evenly distributed in the organic / inorganic hybrid sol liquid.
Is dispersed to form a coating liquid. Of the coating liquid
Viscosity is 100-4000 cP ₀And high, leave it for a few hours
No sedimentation of solid lubricating particles was observed.

[Step 2] The coating liquid prepared in step 1 is applied to the surface of a substrate. Examples of the base material include synthetic resin, glass, metal, and ceramic. The invention is particularly usefully applied to, for example, a transfer fixing member for an electrophotographic apparatus. The transfer / fixing member includes an intermediate transfer belt, an intermediate transfer drum, a transfer / fixing belt, a fixing roller, a fixing belt, and the like. Examples of the material include polyimide resin (PI), polycarbonate resin (PC), and polybutylene. Examples include polyester resins such as terephthalate (PBT), polyarylate (PAR), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET), and thermoplastic resins such as polyurethane resin (PU) and polyamide resin (PA). Or mixed or used as a polymer alloy.

When the base material is made of a resin material,
Before applying the coating liquid on the member, the surface of the member is cleaned in advance and subjected to ultraviolet irradiation treatment or Na
It may be processed by OH chemical etching.

As a method of applying the coating liquid on the surface of the base material, known methods can be used, for example, dip coating, spray coating, roll coating,
A method such as flow coating can be used.

[Step 3] The coating liquid applied to the substrate surface in step 2 is subjected to a heat treatment to form a super water-repellent coating.

Usually, the conditions of the heat treatment are 60 to 450
C. x 20 seconds to 7 hours is preferable.

The super water-repellent coating thus obtained is excellent in water repellency, and the contact angle with water can be at least 140 ° in addition to the effect of the physical shape of the surface.

The super water-repellent coating of the present invention uses an organic component, in particular, a polydimethylsiloxane terminated with a silanol terminal. The super water-repellent coating has excellent flexibility due to the flexible siloxane bond which is the main skeleton of polydimethylsiloxane. It shows properties and elasticity, and shows good adhesion to the above-mentioned substrate.

Hereinafter, the present invention will be described more specifically with reference to examples, but the scope of the present invention is not limited to these examples. [Example 1] Tetraisopropoxytitanium was used as an inorganic component, and silanol-terminated polydimethylsiloxane (weight average molecular weight 6,000) was used as an organic component. By mixing the terminal silanol polydimethylsiloxane: the tetraisopropoxytitanium: ethyl acetoacetate: water in a mixing ratio of 0.25: 1: 2: 2 using ethanol as a solvent and thoroughly stirring for 0.5 hour, Sufficient hydrolysis of the tetraisopropoxytitanium and partial condensation polymerization with the terminal polydimethylsiloxane are performed to
An inorganic hybrid sol solution was prepared. Further, polytetrafluoroethylene particles having a particle size of 5 ± 2 μm were added to the organic / inorganic hybrid sol solution, and the mixture was stirred to prepare a coating solution. The mixing and stirring were performed twice using a vacuum defoaming stirrer under conditions of revolution of 1600 rpm, rotation of 500 rpm, and stirring for 5 minutes. The viscosity of the coating liquid thus prepared was 3110 cP ₀ . The substrate to which the coating liquid is applied is a polyimide substrate of a transfer roll for an electrophotographic device, and sufficiently removes dirt on the surface of the substrate,
After a further ultraviolet irradiation treatment, the substrate was set on a flow coat machine. The coating liquid ejection section of the flow coat machine was traversed at a speed of 0.15 mm / sec, and the coating liquid was applied onto the substrate. Thereafter, heat treatment was performed at 200 ° C. for 0.5 hour and at 350 ° C. for 0.1 hour in an air atmosphere to form a super water-repellent film on the surface of the substrate.

The thickness of the super water-repellent film obtained in Example 1 was 67.5 μm, the surface roughness Ra was 3.1 μm, the pencil hardness was B, the contact angle with water was 145 °, and the static friction coefficient was 0.5. 1
6. The coefficient of dynamic friction is 0.07, and the transfer roll having such a super water-repellent coating is excellent in toner releasability.

Example 2 Tetraisopropoxytitanium was used as an inorganic component and silanol-terminated polydimethylsiloxane (weight average molecular weight 600
0) was used. By mixing the terminal silanol polydimethylsiloxane: the tetraisopropoxytitanium: ethyl acetoacetate: water in a mixing ratio of 0.25: 1: 2: 2 using ethanol as a solvent and thoroughly stirring for 0.5 hour, A sufficient hydrolysis of the tetraisopropoxytitanium and a partial condensation polymerization with the terminal polydimethylsiloxane were carried out to prepare an organic / inorganic hybrid sol solution. Further, the organic-inorganic hybrid sol solution has a particle size of 5 ± 2μ.
m of aluminum oxide particles were added and mixed and stirred to prepare a coating solution. The mixing and stirring were performed twice using a vacuum defoaming stirrer under conditions of revolution of 1600 rpm, rotation of 500 rpm, and stirring for 5 minutes. The viscosity of the coating liquid thus prepared was 444 cP ₀ . The base material to which the coating liquid is applied is a polyarylate-polyethylene naphthalate polymer alloy base material of a fixing roll for an electrophotographic apparatus. The substrate was set on a flow coat machine. The coating liquid ejection section of the flow coat machine was traversed at a speed of 0.15 mm / sec, and the coating liquid was applied onto the substrate. Thereafter, heat treatment was performed at 200 ° C. for 0.5 hour and at 350 ° C. for 0.1 hour in an air atmosphere to form a super water-repellent film on the surface of the substrate.

The film thickness of the super water-repellent coating obtained in Example 2 was 65.5 μm, the surface roughness Ra was 3.3 μm, the pencil hardness was F, the contact angle with water was 143 °, and the static friction coefficient was 0.5. 3
3. The coefficient of kinetic friction is 0.20, and the fixing roll having such a super water-repellent coating has low adhesion to toner.

COMPARATIVE EXAMPLE 1 Tetraisopropoxytitanium was used as an inorganic component, and silanol-terminated polydimethylsiloxane (weight average molecular weight 600
0) was used. By mixing the terminal silanol polydimethylsiloxane: the tetraisopropoxytitanium: ethyl acetoacetate: water in a mixing ratio of 0.25: 1: 2: 2 using ethanol as a solvent and thoroughly stirring for 0.5 hour, A sufficient hydrolysis of the tetraisopropoxytitanium and a partial condensation polymerization with the terminal polydimethylsiloxane were carried out to prepare an organic / inorganic hybrid sol solution. The substrate on which the organic / inorganic hybrid sol is applied is a polyimide substrate of a transfer roll as in Example 1, and after sufficiently removing dirt on the surface of the substrate and further performing an ultraviolet irradiation treatment, Was set on a flow coat machine. The coating liquid discharge section of the flow coat machine is 0.15 mm / se
The organic / inorganic hybrid sol liquid was applied on the substrate by traversing at a speed of c. Then under air atmosphere,
Heat treatment was performed at 200 ° C. for 0.5 hour and at 350 ° C. for 0.1 hour to form an organic-inorganic hybrid coating on the surface of the substrate.

The thickness of the organic-inorganic hybrid film obtained in Comparative Example 1 was 20 μm, and the surface roughness Ra was 0.04.
μm, the pencil hardness was B, and the contact angle was 105 °.

[Comparative Example 2] Mixed solution A in which tetraisopropoxytitanium and ethanol were mixed at a molar ratio of 1: 4
, Water, ethanol and hydrochloric acid in a molar ratio of 1: 4: 0.08
And the mixed solvent B was slowly added dropwise to the mixed solution A while stirring with a stirrer to hydrolyze the tetraisopropoxytitanium.
i-sol was used. The Ti sol solution was further stirred for 0.5 hours to sufficiently hydrolyze the tetraisopropoxytitanium and partially polymerize it by dehydration. Further, polytetrafluoroethylene particles having a particle size of 5 ± 2 μm were added to the Ti sol solution, and mixed and stirred to prepare a coating solution. The mixing and stirring is performed by a vacuum defoaming stirrer with a revolution of 1600 rpm.
The rotation was performed twice under the conditions of rotation at 500 rpm and stirring for 5 minutes.
As in Example 1, the surface of the polyimide substrate of the transfer roll was sufficiently cleaned and subjected to an ultraviolet irradiation treatment, and then the substrate was set on a flow coat machine. The coating solution discharge section of the flow coat machine was traversed at a speed of 0.15 mm / sec, and the Ti sol solution was applied on the substrate. Then, at 250 ° C for 0.5 hour in an air atmosphere, 35
Heat treatment was performed at 0 ° C. for 0.1 hour to form a titanium oxide film on the surface of the substrate.

The thickness of the titanium oxide film obtained in Comparative Example 2 was 20 μm, and the contact angle was 118 °.

The contact angles of the super water-repellent coatings obtained in Examples 1 and 2 were 145 ° and 143 °,
Compared with the contact angle of the organic-inorganic hybrid coating obtained in Comparative Example 1 (105 °) and the contact angle of the titanium oxide coating obtained in Comparative Example 2 (118 °), the contact angle of the super water-repellent coating was compared. Is quite large.

[0042]

According to the present invention, super water repellency can be easily provided by coating an inorganic hybrid coating film in which organic / solid lubricating particles are dispersed on the surface of a substrate.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 3/18 102 C09K 3/18 102 104 104 G03G 15/16 103 G03G 15/16 103 15/20 103 15 / 20 103 (72) Inventor Takuya Shindo 1900, Ifuna-cho, Suzuka-shi, Mie Prefecture Inside Suzuka Fuji Xerox Co., Ltd. (72) Inventor Shingo Katayama 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (72) Inventor Noriko Yamada 20-1 Shintomi, Futtsu-shi, Chiba F-term in the Technology Development Division of Nippon Steel Corporation (Reference) 2H032 AA05 BA23 2H033 AA09 AA25 BB04 BB26 BB29 BB31 4F100 AK18A AK49 AK52A AR00A AT00B BA16 CA19 DA11 DD31 DE01A EH462 EJ422 GB41 JB06 JB06A 4H020 BA12 BA32 4J038 CD122 CD132 DL031 DM021 GA03 HA036 HA066 HA166 JA05 JA 19 JA33 KA04 KA06 MA14 NA07 NA12 PB11 PC02 PC03 PC08

Claims (10)

[Claims] 1. An organic / inorganic hybrid coating comprising a metal and / or metalloid alkoxide and an organosilicon compound by a sol-gel method, wherein solid lubricating particles are dispersed in the coating. Water repellent coating 2. The super water-repellent coating according to claim 1, wherein the organosilicon compound is a polydimethylsiloxane having silanol terminals. 3. The super-water-repellent coating according to claim 1, wherein the solid lubricating particles are polytetrafluoroethylene. 4. The super water-repellent coating according to claim 1, wherein the contact angle with water is 140 ° or more. 5. The super-water-repellent film according to claim 1, wherein said super-water-repellent film is formed on a substrate of a transfer fixing member for an electrophotographic apparatus. 6. A coating liquid preparation step 1 in which solid lubricating particles are dispersed in an organic / inorganic hybrid sol liquid comprising an alkoxide of a metal and / or metalloid and an organosilicon compound to prepare a coating liquid. A method for producing a super water-repellent film, comprising: a coating step 2 for coating a material; and a heating step 3 for forming a super-water-repellent film by heat treatment. 7. The method according to claim 6, wherein the organosilicon compound is a polydimethylsiloxane having silanol terminals. 8. The method according to claim 6, wherein the solid lubricating particles are polytetrafluoroethylene. 9. The method for producing a super water-repellent coating according to claim 6, wherein the contact angle with water is 140 ° or more. 10. The method for producing a super water-repellent coating according to claim 6, wherein said substrate is a transfer fixing member for an electrophotographic apparatus.