WO2013151187A1

WO2013151187A1 - Process for producing article having fluorine-containing silane-based coating

Info

Publication number: WO2013151187A1
Application number: PCT/JP2013/060879
Authority: WO
Inventors: Eiji Sakamoto; Kakeru Hanabusa; Teruyuki Fukuda; Takayuki Araki; Kaori Ozawa
Original assignee: Daikin Industries, Ltd.
Priority date: 2012-04-05
Filing date: 2013-04-04
Publication date: 2013-10-10
Also published as: TW201400562A

Abstract

The present invention provides a process for producing an article comprising a fluorine-containing silane-based coating on a coating surface of an organic base material, wherein the process comprises the steps of: (a) forming a precursor coating on a surface of the organic base material by using a composition comprising an unsaturated silane compound, a photocatalyst and a photocurable organic material; (b) forming a cured coating derived from the precursor coating on the surface of the organic base material by photo-irradiation to the precursor coating; and (c) forming a fluorine-containing silane-based coating on the cured coating directly or via an inorganic material layer by using a surface treatment agent comprising a fluorine-containing silane compound. The process can form the fluorine-containing silane-based coating having high friction durability is provided.

Description

DESCRIPTION

PROCESS FOR PRODUCING ARTICLE HAVING FLUORINE-CONTAINING

SILANE-BASED COATING

Cross-Reference to Related Applications

[0001]

This application claims priority to and the benefit of U.S. provisional application No. 61/620,690, filed April 5, 2012, the entire contents of which are incorporated herein by reference.

Technical Field

[0002]

The present invention relates to a process for producing an article having a fluorine-containing silane- based coating, more specifically, a process for producing an article having a fluorine-containing silane-based coating on a coating surface of an organic base material. The present invention also relates to an article which is producible by the process.

Background Art

[0003]

Because a clear plastic such as an acrylate resin and a polycarbonate is lightweight and readily processable, its application has been extending progressively as an alternative material to an inorganic glass. The clear plastic may be subjected to various surface-treatments according to its use. For example, because the clear plastic has lower surface hardness and is easily scratched in comparison with the inorganic glass, they may be subjected to a hard coating treatment in order to prevent these problems.

[0004]

Conventionally, in use of an optical member, an antifouling coating as a surface treatment layer is formed on a base material consisting of an inorganic glass in order to prevent from adhering a fouling such as fingerprints. As an antifouling coating agent, a surface treatment agent comprising a fluorine-containing silane compound having a perfluoropolyether group and a hydroxyl group or a hydrolyzable group which is bonded to Si as an active ingredient is known (See Patent Literatures 1 and 2) .

[0005]

When the above clear plastic is applied to an optical member, it is desired to surface-treat it so that antifouling property is provided. In a conventional surface treatment process of an organic base material consisting of a clear plastic, etc., a hard coating with antifouling property as a surface treatment layer is formed by using a surface treatment agent comprising an ultraviolet-curing acrylic hard coating agent and a perfluoropolyether- containing compound having a carbon- carbon double bond as an antifouling additive (see Patent Literature 3) , and applying this surface treatment agent to the organic base material and ultraviolet-curing it.

Citation List

[0006]

Patent Literature

Patent Literature 1: WO 97/07155

Patent Literature 2: JP 2008-534696 A

Patent Literature 3: WO 03/002628

Patent Literature 4: JP 2004-250474 A

Patent Literature 5: JP 2007-332262 A

Patent Literature 6: JP 2003-137944 A

Summary of Invention

[0007]

A surface treatment layer (or coating) is required to have high .durability in order to provide a base material with desired functions for a long time. In particular, in use of an optical member such as glasses and a touch panel which are required to have optical transparency or clarity, it is required that the surface treatment layer has high antifouling property and high friction durability (in other words, maintaining initial properties such as antifouling property, etc., against repeating frictions).

[0008]

However, the conventional surface treatment process of an organic base material is insufficient to meet requirements of high antifouling property and high friction durability. In particular, there is a problem that antifouling property (initial antifouling property) which is provided by the conventional surface treatment process wherein an antifouling additive is added to a hard coating agent is lower than antifouling property of a fluorine- containing silane-based coating formed by using a surface treatment agent comprising a fluorine-containing silane compound.

[0009]

The fluorine-containing silane-based coating has high adherence strength to an inorganic base material such as an inorganic glass, etc., that is, has high friction durability. However, the fluorine-containing silane-based coating has low adherence strength to an organic base material, therefore, cannot have high friction durability.

[0010]

Therefore, it is suggested that a hard coating layer having a hydrophilic group is formed on an organic base material, and then a fluorine-containing silane-based coating is formed thereon (see Patent Literature 4) . However, friction durability provided by such process is not always sufficient.

[0011]

Alternatively, it can be thought that a silicon dioxide coating is formed on an organic base material, and then a fluorine-containing silane-based coating is formed thereon. By the process, high adherence strength between the fluorine-containing silane-based coating and the silicon dioxide coating is achieved, but adherence strength between the silicon dioxide coating and the organic base material is insufficient, resultingly, high friction durability cannot be provided.

[0012]

On the other hand, an organic-inorganic complex which has excellent adherence to a base material is known (see Patent Literature 4) . However, the organic- inorganic complex comprises a functional material so that the complex provides desired functions in itself, and it is not intended to form a surface treatment layer such as the fluorine-containing silane-based coating, etc. on the organic-inorganic complex.

[0013]

An object of the present invention is to provide a process for producing an article comprising a fluorine- containing silane-based coating on a coating surface of an organic base material, wherein the process can form the fluorine-containing silane-based coating having high friction durability.

[0014]

According to one aspect of the present invention, there is provided a process for producing an article comprising a fluorine-containing silane-based coating (outermost layer) on a coating surface of an organic base material, wherein the process comprises the steps of:

(a) forming a precursor coating on a surface of the organic base material by using a composition comprising an unsaturated silane compound, a photocatalyst and a photocurable organic material;

(b) forming a cured coating derived from the precursor coating on the surface of the organic base material by photo-irradiation to the precursor coating; and

(c) forming a fluorine-containing silane-based coating on the cured coating directly or via an inorganic material layer by using a surface treatment agent comprising a fluorine-containing silane compound.

In the process for producing of the present invention, the order of performing the steps (a) - (c) is not particularly limited. In particular, the steps (b) and (c) can be performed with any suitable timing as long as eventually the cured coating is formed, and the fluorine- containing silane-based coating is formed on the cured coating (directly or via the inorganic material layer) .

[0015]

According to the above process for producing an article of the present invention, a fluorine-containing silane-based coating having high friction durability can be formed on a coating surface of an organic base material. Although the present invention is not bound to any theory, the reason for this can be considered as follows. According to the above process for producing an article of the present invention, during the step (b) , the photocatalyst is activated by the light irradiated to the precursor coating, and acts on the surface of the organic base material to react the surface with the unsaturated silane compound, thereby the bond between them is formed. At the same time, the photocurable organic material is cured with addition-reacting with the unsaturated silane compound. The cured coating obtained so has high adherence strength to an organic base material due to such bond formation and addition reaction. In addition, during the step (c) , the fluorine-containing silane compounds are reacted with each other to form a bond between these compounds as well as are reacted with the surface of the cured coating (or underlayer) to form a bond between them. A fluorine-containing silane-based coating obtained so has high coating strength in itself as well as high adherence strength to the cured coating. As a result, the fluorine- containing silane-based coating having high friction durability is formed on the surface of the organic base material via the cured coating.

[0016]

The unsaturated silane compound may be, for example, a compound of the following general formula:

wherein :

T is a hydroxyl group or a hydrolyzable group;

R¹¹ is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms;

x is an integer from 1 to 3;

R¹² is a divalent organic group; and

y is 0 or 1.

[0017]

The photocatalyst used in the present invention preferably consists of a metal compound, but not particularly limited thereto.

[0018] The fluorine-containing silane-based coating has water-repellency, oil-repellency, antifouling property, and the like by comprising a fluorine atom in addition to the above friction durability. In particular, the fluorine- containing silane compound preferably has a perfluoropolyether group and a hydroxyl group or a hydrolyzable group which is bonded to Si. The fluorine- containing silane-based coating obtained by using this compound has high friction durability, water-repellency, oil-repellency, antifouling property (for example, preventing from adhering a fouling such as fingerprints) , surface slip property (or lubricity, for example, wiping property of a fouling such as fingerprints), and the like.

[0019]

Examples of the fluorine-containing silane compound having a hydroxyl group or a hydrolyzable group which is bonded to Si and a perfluoropolyether group include one or more compounds of any of the following general formulae (la) and (lb) : Y

Rf^iOQFJs-iOQFgia-iOCjFJb-tOCF^- (1 a)

X-(CCH₂)_r(CF₂¾CF-(OC F₈)_-{OC_JF₆)_a-{OC₂F₄)_b-(OCF₂)_c-OCFiCF₂)_d-{CH₂C)_m-X

I

■nT_nSi-(CH₂) Z (CHjJ e-SlTnR n

·^■■ (1 b)

wherein:

Rf¹ is an alkyl group having 1 to 16 carbon atoms which may or may not be substituted by one or more fluorine atoms ,- a, b, c and s are each independently an integer from 0 to 200, wherein the sum of a, b, c and s is at least 1, and the occurrence order of the respective repeating units in parentheses with the subscript a, b, c or s is not limited in the formulae;

d and f are each independently 0 or 1 ;

e and g are each independently an integer from 0 to 2 ; m and 1 are each independently an integer from 1 to

10;

X is a hydrogen atom or a halogen atom;

Y is a hydrogen atom or a lower alkyl group;

Z is a fluorine atom or a lower fluoroalkyl group;

T is a hydroxyl group or a hydrolyzable group;

R¹ is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms ; and

n is an integer from 1 to 3.

[0020]

Other examples of the fluorine-containing silane compound having a hydroxyl group or a hydrolyzable group which is bonded to Si and a perfluoropolyether group include one or more compounds of any of the following general formulae (2a) and (2b) :

Rf²-(OC₄F_s OC₃F₆)_a-(0^ ^{■ ■ ■} (2a)

Z

R² _3-nTnSi-(CH₂)_k-0-(CH₂)_r(CF₂)_fCF-

Z

^ -(OQFe^-iOCaFeJ^iOC_jF^b-iOCF^.-OCFiCF^d-iCH^.-O-iCH^rSiT.R^.,

I

^{1 ■ ■} · (2b)

wherein :

Rf² is an alkyl group having 1 to 16 carbon atoms which may or may not be substituted by one or more fluorine atoms ;

a, b, c and s are each independently an integer from 0 to 200, wherein the sum of a, b, c and s is at least 1, and the occurrence order of the respective repeating units in parentheses with the subscript a, b, c or s is not limited in the formulae;

d and f are each independently 0 or 1; h and j are 1 or 2 ;

i and k are each independently an integer from 2 to

20;

Z is a fluorine atom or a lower fluoroalkyl group; T is a hydroxyl group or a hydrolyzable group;

R² is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms; and

n is an integer from 1 to 3.

[0021]

According to other aspect of the present invention, there is also provided an article which comprises

an organic base material,

a coating formed on a surface of the organic base material, which comprises a cured material of an unsaturated silane compound and a photocurable organic material, and a photocatalyst , and

a fluorine-containing silane-based coating formed on the coating.

The article can be produced by the process for producing of the present invention. In the article, even if the organic base material is used, the fluorine- containing silane-based coating having high antifouling property is formed on the coating surface (or outermost layer) of the organic base material .

[0022] The organic base material may be clear. According to the article of the present invention, clarity of the organic base material can be substantially maintained.

[0023]

The fluorine-containing silane-based coating can provide antifouling property (initial antifouling property) by comprising a fluorine atom, thereby being able to be suitably used as an antifouling coating.

[0024]

The article produced by the present invention may be, for example, an optical member, but not particularly limited thereto. The present invention may be suitably applied to the optical member because it is highly demanded to have improved friction durability.

[0025]

According to the present invention, a fluorine- containing silane-based coating having high friction durability can be formed by forming a cured coating between an organic base material and a fluorine-containing silane- based coating from a composition comprising an unsaturated silane compound, a photocatalyst and a photocurable organic material .

Brief Description of Drawings

[0026] Fig. 1 is a graph showing friction durability of the antifouling layers which were produced in Examples 1-3 and Comparative Examples 1-4. Description of Embodiments

[0027]

Hereinafter, the process for producing an article of the present invention and an article produced by the process will be described in detail through an embodiment of the present invention, although the present invention is not limited thereto.

[0028]

Firstly, the organic base material is provided. The base organic material usable in the present invention may be a base material of which at least surface consists of an organic material. The "organic material" used in the present invention may be that comprising an organic substance, typically it is a material consisting of one or more organic substances, but may be a complex (hybrid) or an admixture material comprising one or more organic substances and an inorganic substance.

[0029]

The organic material may be any suitable organic material. For example, a general plastic material such as an acrylate resin ( (metha) acrylic acid ester polymer), polycarbonate, polyethylene terephthalate , polystyrene, polyethylene, polypropylene, polyvinyl chloride, an AS resin, and an ABS resin can be used. In addition, a silicone resin, a fluorene resin, a cycloolefin resin, an epoxy resin, a TAC resin, a fluorine resin, a MS resin, polyvinyl alcohol, diallyl phthalate, polyimide, a phenol resin, a melamine resin, an urea resin, an unsaturated polyester resin, polyurethane , a diallyl phthalate resin, an alkyd resin and the like can be used. Furthermore, an organic-inorganic hybrid resin can also be used.

[0030]

The present invention can be suitably used when the organic base material is clear. The clear organic base material consists of, for example, a clear acrylate resin, polycarbonate, polyethylene terephthalate, a silicone resin (for example, see Patent Literature 6) and the like or a commercially available alternative material to an inorganic glass such as "SILPLUS" (registered trademark; manufactured by Nippon Steel Chemical Co., Ltd.) and "ORGA" (registered trademark; manufactured by Nippon Synthetic Chemical Industry Co., ltd.). The "clear" in the present invention may be that which is generally recognized to be clear, for example, represents that having 5% or less of haze value.

[0031]

For example, when an article to be produced is an optical member, any layer (or coating) consisting of an organic material such as a hard coating layer or an antireflection layer may be formed on the surface (outermost layer) of the base material. As the antireflection layer, either a single antireflection layer or a multi antireflection layer may be used. When an article to be produced is an optical member for a touch panel, it may have a transparent electrode, for example, a thin layer comprising indium tin oxide (ITO) , indium zinc oxide, or the like on a part of the surface of the organic base material (glass) . Furthermore, the organic base material may have an antistatic layer, an insulating layer, an adhesive layer, a protecting layer, a decorated frame layer (I-CON) , an atomizing layer, a hard coating layer, a polarizing film, a phase difference film, a liquid crystal display module, and the like, according to its specific specification.

[0032]

The shape of the organic base material is not specifically limited but may be may be in form of a plate, a film, a compact, or others. The region of the surface of the base material on which the cured coating and the fluorine-containing silane-based coating (outermost layer) should be formed may be at least a part of the surface of the base material, and may be appropriately determined depending on use, the specific specification, and the like of the article to be produced.

[0033]

The organic base material may be subjected to any pretreatment . Examples of the pretreatment include a plasma treatment (for example, corona discharge) or an ion beam irradiation. The plasma treatment may be suitably used to introduce or increase a hydroxyl group on the surface of the base material, further, to clarify the surface of the base material (remove foreign materials, and the like) . Alternatively, other examples of the pretreatment include a method wherein a monolayer of a surface adsorbent having a carbon-carbon unsaturated bond group is formed on the surface of the base material by using a LB method (Langmuir-Blodgett method) or a chemical adsorption method beforehand, and then, cleaving the unsaturated bond under an atmosphere of oxygen and nitrogen [0034]

On the other hand, a composition comprising an unsaturated silane compound, a photocatalyst and a photocurable organic material (hereinafter, also referred to as "a composition for forming an underlayer" ) is provided. As used herein, the "underlayer" represents a layer on which a surface treatment agent is applied (or a layer on which an inorganic material layer is formed when the inorganic material layer is present between a cured coating and a fluorine-containing silane-based coating) . In this embodiment, the underlayer is a cured coating derived from a composition for forming an underlayer.

[0035]

The unsaturated silane compound can specifically have a carbon-carbon double bond and a hydroxyl group or a hydrolyzable group which is bonded to Si. Examples of the unsaturated silane compound include a compound of the following general formula (may be one compound or a mixture of two or more compounds) .

In the formula:

T and R¹¹ are a group which is bonded to Si, and R¹² is, if present, a spacer group between a vinyl group and a silyl group.

T represents a hydroxyl group or a hydrolyzable group. Examples of the hydrolyzable group include -OA, -OCOA, -O- N=C(A)₂, -N(A)₂, -NHA, halogen (wherein, A is a substituted or unsubstituted, liner or branched alkyl group having 1-3 carbon atoms), and the like, preferably -OA (an alkoxy group) . Examples of A include an unsubstituted alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group; and a substituted alkyl group such as a chloromethyl group. Among them, the alkyl group, in particular the unsabstituted alkyl group is preferable. The hydroxyl group may be that which is generated by hydrolysis of a hydrolyzable group, but not specifically limited thereto.

R¹¹ represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, preferably an alkyl group having 1 to 22 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms.

x is an integer from 1 to 3.

R¹² represents a divalent organic group. The divalent organic group may be a substituted or unsubstituted, liner, branched or cyclic hydrocarbon group having 1 to 10 carbon atoms which may have an ester bond, an ether bond, an amide bond, a sulfide bond, or the like.

y is 0 or 1. When y is 0, R¹² is absent, and a vinyl group and a silyl group are directly bounded to each other.

[0036]

As used herein, the term "photocatalyst " refers to a material which, when exposed to light (excitation light) having higher energy (i.e., shorter wavelength) than the energy gap between the conduction band and the valence band of the crystal, can cause excitation (photoexcitation) of electrons in the valence band to produce a conduction electron and a hole. The photocatalyst may be, for example, a metal compound comprising a metal such as titanium, zinc, tin, iron, bismuth, tungsten and the like. More particularly, examples of the metal compound include titanium oxide, zinc oxide, tin oxide, ferric oxide, dibismuth trioxide, tungsten trioxide, and strontium titanate. As a general photocatalyst, titanium oxide, more particularly, an anatase form or a rutile form of titanium oxide is known. The titanium oxide may be in the form of a superfine particle having 0.1 ym or less of an average primary particle diameter.

[0037]

The photocatalyst is preferably a light-sensitive compound which is sensitive to light having a wavelength of 400 nm or less (in particular, a metal compound) and/or a derivative thereof. The light-sensitive compound may be at least one selected from a metal chelate compound, a metal organic acid salt compound, a metal compound having two or more a hydroxyl group or a hydrolyzable group, a hydrolysate thereof, and a condensation product thereof, preferably, a hydrolysate thereof and/or a condensation product thereof, more preferably, a hydrolysate and/or a condensation product of a metal chelate compound. The derivative of the light-sensitive compound may be, for example, that which is obtained by further condensing a condensation product or the like of a metal chelate compound. The light-sensitive compound and/or the derivative thereof may be chemically bonded to an unsaturated silane compound, be dispersed in the state of non-bonding or be in a mixed state thereof .

[0038]

The photocurable organic material may be any material as long as it is able to be hardened by light- irradiation. The photocurable organic material may be a photocurable resin, in particular, an ultraviolet -curable resin is preferable. For example, ultraviolet-curable acrylate and methacrylate (urethane based, epoxy based, polyester based, polybutadiene based, silicone based, amino resin based, polyether based, polyol based, fluorine based, silane based) or the like can be used, and a commercially available ultraviolet-curable hard coating agent or the like may be used. The photocurable organic material may be monofunctional , but it is preferably multifunctional.

[0039]

The unsaturated silane compound may be contained in the composition for forming an underlayer, for example, at about 0.1-90 parts by weight, preferably about 1-50 parts by weight with respect to 100 parts by weight of the photocurable organic material, and the photocatalyst may be contained, for example, at about 0.01-20 parts by weight, preferably about 0.1-2.0 parts by weight with respect to 100 parts by weight of the photocurable organic material.

[0040]

The composition for forming an underlayer may comprise any suitable additives in addition to these components. Examples of the additives include a polymerization initiator, a photosensitizer, a polymerization inhibitor, a solvent, a curing agent, a cross-linking agent, an ultraviolet screening agent, an ultraviolet absorbing agent, a surface conditioner (a leveling agent), antifoam agent, and the like.

[0041]

A precursor coating is formed on the surface of the organic base material prepared above by using the composition for forming an underlayer. Formation of the precursor coating can be performed by applying the composition for forming the underlayer to the surface of an organic base material so that the surface is coated. The coating method is not specifically limited. Examples of the coating method include dip coating, spin coating, flow coating, spray coating, roll coating, gravure coating, and a similar method.

[0042]

The composition for forming an underlayer may be applied to a surface of a base material after it is diluted with a solvent . The solvent can be appropriately selected in view of stability of the composition for forming an underlayer and volatile property of the solvent, but preferably the following solvents are used: ketone (for example, methyl ethyl ketone, acetone, methyl isobutyl ketone, and the like) , alcohol (for example, a monovalent alcohol such as ethanol and propanol, a polyvalent alcohol such as ethylene glycol, diethylene glycol, propylene glycol (in particular, di-tetra valent alcohol)) , ester (for example, ethyl acetate) , ether (for example, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether acetate) , fluorine-containing alcohol, fluorine-containing ether, and the like. These solvents can be used alone or as a mixture of two or more .

[0043]

Then, if the composition is diluted with a solvent, after a drying step for removing the solvent is appropriately performed, the precursor coating is irradiated with light to form a cured coating derived from the precursor coating on the surface of an organic base material. The cured coating is a coating which comprises cured material of the unsaturated si lane compound and the photocurable organic material, and the photocatalyst . The cured coating thus obtained has high adherence strength to an organic base material and has a reactive part on the surface of the cured coating.

[0044]

Although the present invention is not bound to any theory, it can be considered that the following phenomenon is occurred by light -irradiation. A photocatalyst is activated by light -irradiation, and a surface of an organic base material is hydrophilized by action of the photocatalyst to generate a hydroxyl group and/or a radical on the surface of the organic base material. In addition, a hydrolyzable group which is able to be present in an unsaturated silane compound is hydrolyzed to a hydroxyl group and/or a radical by action of the photocatalyst. A dehydration-condensation and/or a radical reaction between the hydroxyl group and/or the radical in the unsaturated silane compound and the hydroxyl group and/or the radical on the surface of the organic base material are occurred to form a bond between them. At the same time, a photocurable organic material is hardened by light irradiation, and during this curing, a carbon-carbon double bond of the unsaturated silane compound occurs the addition-reaction between the unsaturated silane compounds and/or with a photocurable organic material to cure together. The cured coating thus obtained has high adherence strength to the organic base material due to the formation of bond and the addition-reaction. Additionally, the surface of the cured coating becomes to have a reactive part. The reactive part may be a hydroxyl group or a hydrolyzable group which the unsaturated silane compound originally has, a hydroxyl group and/or a radical generated from the unsaturated silane compound by action of the photocatalyst , or a hydroxyl group and/or a radical generated by hydrophilizing the surface of a cured coating by action of the photocatalyst.

[0045]

The light-irradiation may be generally performed against an exposed surface side of the precursor coating (an opposing surface against a surface contacting with the organic base material) . The wavelength of irradiating light may be any wavelength as long as it can make a photocurable organic material to cure and activate a photocatalyst. Typically, it may be ultraviolet

(wavelength: about 10-400 nm) , but not limited thereto. An amount of light-irradiation can be appropriately selected depending on a type and the like of a photocurable organic material used and a photocatalyst used, for example, the integral of light may be 200-2,000 mJ/cm², but not limited thereto .

[0046]

The thickness of the cured coating is not specifically limited. For the optical member, the thickness of the cured coating is preferably within the range of 1-30 nm in view of optical performance and adherence strength.

[0047]

Then, the cured coating is used as an underlayer, and a fluorine-containing silane-based coating is formed thereon by using a surface treatment agent comprising a fluorine-containing silane compound. The fluorine- containing silane compound has specifically a hydroxyl group or a hydrolyzable group which is bonded to Si. The fluorine-containing silane-based coating thus obtained has high coating strength itself and high adherence strength to the cured coating (underlayer) .

[0048]

Although the present invention is not bound to any theory, he reason for this can be considered as follows. The hydroxyl groups or hydrolyzable groups which are bonded to Si in the fluorine-containing silane compound are reacted with each other to form a bond between these compounds. Additionally, the hydroxyl group or the hydrolyzable group which is bonded to Si in the fluorine- containing silane compound reacts with the reactive group present on the surface of the above cured coating to form a bond between the fluorine-containing silane compound and the underlayer.

[0049] The fluorine-containing silane compound may have a perfluoropolyether group and a hydroxyl group or a hydrolyzable group which is bonded to Si. The perfluoropolyether group contributes to water-repellency, oil-repellency, antifouling property of the fluorine- containing silane-based coating.

[0050]

Examples of the fluorine-containing silane compound having a perfluoropolyether group and a hydroxyl group or a hydrolyzable group which is bonded to Si include a compound of any of the following general formulae (la) and (lb) (may be one compound or a mixture of two or more compounds) .

l^-(OC₄F₈)_s-(OC_JF₆)_a-(OC₂F₄)_b-(OCF₂).-O ^{■ ■} (1 a)

Y Y

X-{CCH₂)_r(CF₂)_fCF-(OQF₈)_s-{OC₃F₆)₃-{OC₂F₄)_b-(OCF₂)_c-OCF(CF₂)_d-{CH₂q_m-X

RVnT_nSi-(CH₂)_g z Z (CH₂) _e-SiT_nRVn

^■■■(1b)

In these formulae:

Rf¹ is an alkyl group having 1-16 carbon atoms which may or may not be substituted by one or more fluorine atoms, preferably an alkyl group having 1-3 carbon atoms which may or may not be substituted by one or more fluorine atoms. Preferably, the above alkyl group which may or may not be substituted by one or more fluorine atoms is a perfluoroalkyl group.

Subscripts a, b, c and s represent the repeating number of each of four repeating units of perfluoropolyether which constitute a main backbone of the polymer, and are each independently an integer from 0 to 200 wherein the sum of a, b, c and s is at least 1, preferably an integer from 1 to 100. The occurrence order of the respective repeating units in parentheses with the subscript a, b, c or s is not limited in the formulae. Among these repeating units, the - (OC₄F₈) - group may be any of - (OCF₂CF₂CF₂CF₂) -, - (OCF (CF₃) CF₂CF₂) - , - (0CF₂CF (CF₃) CF₂) - , - (OCF₂CF₂CF(CF₃) ) -, - (OC(CF₃)₂CF₂) -, - (OCF₂C (CF₃) ₂) - , (OCF(CF₃)CF(CF₃) ) -, - (OCF (C₂F₅) CF₂) - and - (0CF₂CF (C₂F₅) ) - , preferably - (OCF₂CF₂CF₂CF₂) . The - (OC₃F₆) - group may be any of - (OCF₂CF₂CF₂) -, - (OCF (CF₃) CF₂) - and - (OCF₂CF (CF₃ ) ) - , preferably - (OCF₂CF₂CF₂) - . The - (OC₂F₄) - group may be any of -(OCF₂CF₂)- and - (OCF (CF₃ ) ) - , preferably -(OCF₂CF₂)-.

Subscripts d and f are each independently 0 or 1.

Subscripts e and g are each independently an integer from 0 to 2.

Subscripts m and 1 are each independently an integer from 1 to 10.

X is a hydrogen atom or a halogen atom. The halogen atom is preferably an iodine atom, a chlorine atom, or a fluorine atom.

Y is a hydrogen atom or a lower alkyl group. The lower alkyl group is preferably an alkyl group having 1-20 carbon atoms .

Z is a fluorine atom or a lower fluoroalkyl group. The lower fluoroalkyl group is, for example, a fluoroalkyl group having 1-3 carbon atoms, preferably a perfluoroalkyl group having 1-3 carbon atoms, more preferably a trifluoromethyl group or a pentafluoroethyl group, further preferably a trifluoromethyl group. Representatively, Z is a fluorine atom, and d and f are 1.

T and R¹ are a group bonded to Si.

T is a hydroxyl group or a hydrolyzable group. Examples of the hydrolyzable group include -OA, -OCOA, -O- N=C(A)₂, -N(A)₂, -NHA, halogen (wherein, A is a substituted or unsubstituted alkyl group having 1-3 carbon atoms) , and the like. The hydroxyl group may be that which is generated by hydrolysis of a hydrolyzable group, but not specifically limited thereto.

R¹ is a hydrogen atom or an alkyl group having 1-22 carbon atoms, preferably an alkyl group having 1-22 carbon atoms, more preferably an alkyl group having 1-3 carbon atoms .

Subscript n is an integer from 1 to 3. [0051]

Other examples of the fluorine-containing silane compound having a perfluoropolyether group and a hydroxyl group or a hydrolyzable group which is bonded to Si include a compound of any of the following general formulae (2a) and (2b) (may be one compound or a mixture of two or more compounds) .

Rf OC₄F_s)_s-(OC₃F₆)_a-(OC₂F₄)_b-^ ^■■■ (2a)

Z

R n nSi-(CH₂)_k-0-(CH₂)_r(CF₂)_fCF- *

Z

^ -(OC₄F₈}_s-{OC3F₆)_a-{OC₂F₄)_b-(OCF₂)_c-OCF(CF₂)_d-(CH₂)_h-0-(CH₂}_rSiT_nR n

I

¹ - - - (2b)

In these formulae:

Rf² is an alkyl group having 1-16 carbon atoms which may or may not be substituted by one or more fluorine atoms, preferably an alkyl group having 1-3 carbon atoms which may or may not be substituted by one or more fluorine atoms.

Preferably, the above alkyl group which may or may not be substituted by one or more fluorine atoms is a perfluoroalkyl group.

Subscripts a, b, c and s represent the repeating number of each of four repeating units of perfluoropolyether which constitute a main backbone of the polymer, and are each independently an integer from 0 to 200 wherein the sum of a, b, c and s is at least 1, preferably an integer from 1 to 100. The occurrence order of the respective repeating units in parentheses with the subscript a, b, c or s is not limited in the formulae. Among these repeating units, the - (0C₄F₈) - group may be any of - (OCF₂CF₂CF₂CF₂) -, - (OCF (CF₃) CF₂CF₂) - , - (0CF₂CF (CF₃) CF₂) - , - (OCF₂CF₂CF(CF₃) ) -, - (OC(CF₃)₂CF₂) -, - (0CF₂C (CF₃) ₂) - , (OCF(CF₃)CF(CF₃) ) -, - (OCF(C₂F₅)CF₂) - and - (0CF₂CF (C₂F₅) ) - , preferably - (OCF₂CF₂CF₂CF₂) . The - (OC₃F₆) - group may be any of - (OCF₂CF₂CF₂) -, - (OCF(CF₃) CF₂) - and - (OCF₂CF (CF₃ ) ) - , preferably - (OCF₂CF₂CF₂) - . The - (0C₂F₄) - group may be any of -(OCF₂CF₂)- and - (OCF (CF₃) ) - , preferably - (OCF₂CF₂) - .

Subscripts d and f are each independently 0 or 1.

Subscripts h and j are each independently 1 or 2.

Subscripts i and k are each independently an integer from 2 to 20.

T and R² are a group bonded to Si. T is a hydroxyl group or a hydrolyzable group. Examples of the hydrolyzable group include -OA, -OCOA, -0- N=C(A)₂, -N(A)₂, -NHA, halogen (wherein, A is a substituted or unsubstituted alkyl group having 1-3 carbon atoms) , and the like. The hydroxyl group may be that which is generated by hydrolysis of a hydrolyzable group, but not specifically limited thereto.

R² is a hydrogen atom or an alkyl group having 1-22 carbon atoms, preferably an alkyl group having 1-22 carbon atoms, more preferably an alkyl group having 1-3 carbon atoms .

Subscript n is an integer from 1 to 3.

[0052]

These exemplified fluorine-containing silane compounds may have, for example, 1,000-12,000 of an average molecular weight. In this range, the compounds preferably have 2,000-10,000 of an average molecular weight in view of friction durability. As used herein, the "average molecular weight" refers to a number average molecular weight.

[0053]

A surface treatment agent (or a surface treatment compound) comprising the exemplified fluorine-containing silane compound can provide water-repellency, oil- repellency, antifouling property, surface slip property (or lubricity), or the like.

[0054]

The composition of a surface treatment agent usable in the present invention may be appropriately selected depending on the functions required in the fluorine- containing silane-based coating.

[0055]

For example, the surface treatment agent may comprise a fluoropolyether compound which may be also understood as a fluorine-containing oil (hereinafter referred to as "a fluorine-containing oil" for the purpose of distinguishing from the fluorine-containing silane compound) , preferably a perfluoropolyether compound in addition to the exemplified fluorine-containing silane compound. The fluorine- containing oil contributes to increasing of surface slip property of the fluorine-containing silane-based coating.

[0056]

The fluorine-containing oil may be contained in the surface treatment agent, for example, at 0-80 parts by weight, preferably 0-40 parts by weight with respect to 100 parts by weight of the exemplified fluorine-containing si1ane compound.

[0057]

Examples of the fluorine-containing oil include a compound of the following general formula (3) (a perfluoropolyether compound) .

R²¹- (OC₄F₈)_s-- (OC₃F₆)_a-- (OC₂F₄)_b<- (OCF₂)_c- -R^{22 ■}·· (3) In the formula :

R²¹ is an alkyl group having 1-16 carbon atoms which may or may not be substituted by one or more fluorine atoms, preferably an alkyl group having 1-3 carbon atoms which may or may not be substituted by one or more fluorine atoms. Preferably, the above alkyl group which may or may not be substituted by one or more fluorine atoms is a perfluoroalkyl group.

R²² is a hydrogen atom, a fluorine atom or an alkyl group having 1-16 carbon atoms which may or may not be substituted by one or more fluorine atoms, preferably a fluorine atom or an alkyl group having 1-3 carbon atoms which may or may not be substituted by one or more fluorine atoms. Preferably, the above alkyl group which may or may not be substituted by one or more fluorine atoms is a perfluoroalkyl group.

Subscripts a', b', c' and s' represent the repeating number of each of four repeating units of perfluoropolyether which constitute a main backbone of the polymer, and are each independently an integer from 0 to 300 wherein the sum of a¹, b', C and s' is at least 1, preferably an integer from 1 to 100. The occurrence order of the respective repeating units in parentheses with the subscript a', b¹, c' or s ' is not limited in the formulae. Among these repeating units, the - (OC₄F₈) - group may be any Of - (OCF₂CF₂CF₂CF₂) -, - (OCF(CF₃)CF₂CF₂) -, - (OCF₂CF (CF₃) CF₂) - , - (OCF₂CF₂CF(CF₃) ) -, - (OC(CF₃)₂CF₂) -, - (OCF₂C (CF₃) ₂) - , (OCF(CF₃)CF(CF₃) ) -, - (OCF(C₂F₅)CF₂) - and - (OCF₂CF (C₂F₅) ) - , preferably - (OCF₂CF₂CF₂CF ) . The - (OC₃F₆) - group may be any of - (OCF₂CF₂CF₂) - , - (OCF(CF₃)CF₂) - and - (OCF₂CF (CF₃) ) - , preferably - (OCF₂CF₂CF₂) - . The - (OC₂F₄) - group may be any of -(OCF₂CF₂)- and - (OCF (CF₃ ) ) - , preferably - (OCF₂CF₂) - .

[0058]

Examples of the perfluoropolyether compound of the above general formula (3) include a compound of any of the following general formulae (3a) and (3b) (may be one compound or a mixture of two or more compounds) .

R²¹- (OCF₂CF₂CF₂) _a' - -R²² · · · (3a)

R²¹- (OCF₂CF₂CF₂CF₂) _a.- - (OCF₂CF₂CF₂)_a.· - (OCF₂CF₂)_v. - (OCF₂)_d■ -R²²

^•■•(3b)

In these formulae :

R²¹ and R²² are as defined above; in the formula (3a) , a" is an integer from 1 to 100; and in the formula (3b), s" and a" are each independently an integer from 1 to 30, and b" and c" are each independently an integer from 1 to 300. The occurrence order of the respective repeating units in parentheses with the subscript a", b", c" or s" is not limited in the formulae.

[0059]

The compound of the general formula (3a) and the compound of the general formula (3b) may be used alone or in combination. When they are used in combination, preferably, the ratio of the compound of the general formula (3a) to the compound of the general formula (3b) is 1:1 to 1:30 by weight. By applying such ratio, a surface treatment agent which has a good balance of surface slip property and friction durability can be obtained.

[0060]

From the other point of view, the fluorine-containing oil may be a compound of the general formula: Rf¹-? (wherein, Rf¹ is as defined above) . The compound of Rf¹-F is preferable in that the compound has high affinity for the compound of any of the above general formulae (la) and (lb) and the compound of any of the above general formulae (2a) and (2b) .

[0061]

The fluorine-containing oil may have 1,000-30,000 of average molecular weight. By having this average molecular weight, high surface slip property can be obtained. Representatively, for the compound of the general formula (3a), the average molecular weight is preferably 2,000- 6,000. For the compound of the general formula (3b), the average molecular weight, is preferably 8,000-30,000. Within this range of average molecular weight, high surface slip property can be obtained.

[0062]

In addition, the surface treatment agent may comprise a silicone compound which may be also understood as a silicone oil (hereinafter referred to as "a silicone oil") in addition to the exemplified fluorine-containing silane compound. The silicone oil contributes to increasing of surface slip property of the fluorine-containing silane- based coating.

[0063]

The silicone oil may be contained in the surface treatment agent, for example, at 0-80 parts by weight, preferably 0-40 parts by weight with respect to 100 parts by weight of the exemplified fluorine-containing silane compound.

[0064]

Examples of the silicone oil include, for example, a liner or cyclic silicone oil having 2,000 or less siloxane bonds. The liner silicone oil may be so-called a straight silicone oil and a modified silicon oil. Examples of the straight silicone oil include dimethylsilicone oil, methylphenylsilicone oil, and methylhydrogensilicone oil. Examples of the modified silicone oil include that which is obtained by modifying a straight silicone oil with alkyl, aralkyl, polyether, higher fatty acid ester, fluoroalkyl, amino, epoxy, carboxyl, alcohol, or the like. Examples of the cyclic silicone oil include, for example, cyclic dimethylsiloxane oil.

[0065]

In the fluorine-containing silane-based coating, the silicone oil and/or the fluorine-containing oil are held or trapped by an affinity for the fluorine-containing silane compound .

[0066]

The fluorine-containing silane-based coating can be formed by forming a coating of the surface treatment agent on the surface of the underlayer, and posttreating the coating if necessary, but the present invention is not limited thereto.

[0067]

The formation of the coating of the surface treatment agent can be performed by applying the surface treatment agent on the surface of the underlayer so that the surface is coated. The method of coating is not specifically limited. For example, a wet coating method or a dry coating method can be used.

[0068]

Examples of the wet coating method include dip coating, spin coating, flow coating, spray coating, roll coating, · gravure coating, and a similar method.

[0069]

Examples of the dry coating method include vacuum deposition, sputtering, CVD and a similar method. The specific examples of the vacuum deposition method include resistance heating, electron beam, high-frequency heating, ion beam, and a similar method. The specific examples of the CVD method include plasma-CVD, optical CVD, thermal CVD and a similar method.

[0070]

Additionally, coating can be performed by an atmospheric pressure plasma method.

[0071]

When the wet coating method is used, the surface treatment agent is diluted with a solvent, and then it is applied to the surface of the underlayer. In view of stability of the surface treatment agent and volatile property of the solvent, the following solvents are preferably used: an aliphatic perfluorohydrocarbon having 5-12 carbon atoms (for example, perfluorohexane , perfluoromethylcyclohexane and perfluoro- 1 , 3 - dimethylcyclohexane) ; an aromatic polyfluorohydrocarbon (for example, bis (trifluoromet yl) benzene) ; an aliphatic polyfluorohydrocarbon; a hydrofluoroether (HFE) (for example, an alkyl perfluoroalkyl ether such as perfluoropropyl methyl ether (C₃F₇OCH₃) , perfluorobutyl methyl ether (C₄F₉OCH₃) , perfluorobutyl ethyl ether (C₄F₉OC₂H5) , and perfluorohexyl methyl ether

(C2F₅CF (OCH₃) C₃F₇) (the perfluoroalkyl group and the alkyl group may be liner or branched)), and the like. These solvents may are used alone or as a mixture of two or more. Among them, the hydrofluoroether is preferable, perfluorobutyl methyl ether (C₄F₉OCH₃) and/or perfluorobutyl ethyl ether (C₄F₉OC₂H₅) are particularly preferable.

[0072]

The formation of the coating of the surface treatment agent is preferably performed so that the surface treatment agent is present together with a catalyst for hydrolysis and dehydration-condensation in the coating. Simply, when the wet coating method is used, after the surface treatment agent is diluted with a solvent, and just prior to be applied to the surface of the underlayer, the catalyst may be added to the diluted solution of the surface treatment agent. When the dry coating method is used, the surface treatment agent to which a catalyst has been added itself is used in vacuum deposition, or pellets may be used in vacuum deposition, wherein the pellets is obtained by- impregnating a porous metal such as iron or copper with the surface treatment agent to which the catalyst has been added.

[0073]

As the catalyst, any suitable acid or base can be used. As the acid catalyst, for example, acetic acid, formic acid, trifluoroacetic acid, or the like can be used. As the base catalyst, for example, ammonia, an organic amine, or the like can be used.

[0074]

Then, if necessary, the coating of the surface treatment agent is posttreated. This posttreatment is not specifically limited but, when the surface treatment agent comprises the exemplified fluorine-containing silane compound, for example, may be the method in which water supplying and dry heating are sequentially performed. In particular, it may be performed as follows. When the exemplified fluorine-containing silane compound do not comprise a hydrolyzable group (when all T in the formula are a hydroxyl group) , water supplying is not always needed.

[0075]

After forming the coating of the surface treatment agent on the surface of the underlayer as mentioned above, water is supplied to this coating (hereinafter, referred to as "the second precursor coating" for the purpose of distinguishing from the above precursor coating of the underlayer) . The method of supplying water may be, for example, a method using dew condensation due to the temperature difference between the second precursor coating (and the base material and the underlayer) and ambient atmosphere or a method spraying of water vapor (steam) , but not specifically limited thereto.

[0076]

It is considered that, when water is supplied to the second precursor coating, water acts on the hydrolyzable group bonded to Si present in the fluorine-containing silane compound, thereby enabling rapid hydrolysis of the fluorine-containing silane compound.

[0077]

The supplying of water may be performed under an atmosphere, for example, at a temperature between 0 and 500°C, preferably between 100°C and 300°C. By supplying water at such temperature range, hydrolysis can proceed. The pressure at this time is not specifically limited but simply may be ambient pressure.

[0078]

Then, the second precursor coating is heated on the surface of the underlayer under a dry atmosphere over 60°C. The method of dry heating may be to place the second precursor coating together with the base material and the underlayer in an atmosphere at a temperature over 60°C, preferably over 100°C, and for example, of 500°C or less, preferably of 300°C or less, and at unsaturated water vapor pressure, but not specifically limited thereto. The pressure at this time is not specifically limited but simply may be ambient pressure.

[0079]

Under such atmosphere, between the fluorine-containing silane compounds, the groups being bonded to Si after hydrolysis (the group is, when all T in the general formula are a hydroxyl group, the hydroxyl group; hereinafter the same shall ^· apply) are rapidly dehydration-condensed with each other. As the result, the bond between the fluorine- containing silane compounds is formed.

[0080]

Although the present invention is not bound to any theory, between the fluorine-containing silane compound and the underlayer, the groups being bonded to Si after hydrolysis of the compound are rapidly reacted with the reactive part which is present on the surface of the underlayer. As a result, the bond between the compound and the underlayer is formed.

[0081]

The above supplying of water and dry heating may be sequentially performed by using a superheated water vapor.

[0082]

The superheated water vapor is a gas which is obtained by heating a saturated water vapor to a temperature over the boiling point, wherein the gas, under an ambient pressure, has become to have a unsaturated water vapor pressure by heating to a temperature over 100°C, generally of 500°C or less, for example, of 300°C or less, and over the boiling point. When the base material which the second precursor coating is formed on the underlayer is exposed to a superheated water vapor, firstly, due to the temperature difference between the superheated water vapor and the second precursor coating of a relatively low temperature, dew condensation is generated on the surface of the second precursor coating, thereby supplying water to the second precursor coating. Presently, as the temperature difference between the superheated water vapor and the second precursor coating decreases, water on the surface of the second precursor coating is evaporated under the dry atmosphere due to the superheated water vapor, and an amount of water on the surface of the second precursor coating gradually decreases. During the amount of water on the surface of the second precursor coating is decreasing, that is, during the second precursor coating is under the dry atmosphere, the second precursor coating contacts with the superheated water vapor, as a result, the second precursor coating is heated to the temperature of the superheated water vapor (temperature over 100°C under ambient pressure) . Therefore, by using a superheated water vapor, supplying of water and dry heating are enabled to be sequentially carried out simply by exposing the base material which the precursor coating is formed on the underlayer to a superheated water vapor.

[0083]

The posttreatment can be performed as mentioned above.

The posttreatment may be performed for the purpose of further increasing friction durability, but it should be noted that this posttreatment is not essential in producing the article of the present invention. For example, after the surface treatment agent is applied to the surface of the underlayer, it may simply be stood.

[0084]

As mentioned above, the underlayer is formed on the surface of the organic base material, and the fluorine- containing silane-based coating is formed on the underlayer to produce the article of the present invention. In the article thus obtained, the fluorine-containing silane-based coating has high antifouling property and high friction durability, therefore the fluorine-containing silane-based coating is suitably used as an antifouling coating. In particular, by using the surface treatment agent comprising the exemplified fluorine-containing silane compound, the fluorine-containing silane-based coating having water- repellency, oil-repellency, antifouling property (for example, preventing from adhering a fouling such as fingerprints) , surface slip property (or lubricity, for example, wiping property of a fouling such as fingerprints) and the like is formed, and it is suitably used as a functional thin coating.

[0085]

The article of the present invention is not specifically limited to, but may be an optical member. Examples of the optical member include the followings: lens of glasses, or the like; a front surface protective plate, an antireflection plate, a polarizing plate, or an antiglare plate on a display such as PDP and LCD; a touch panel sheet of an instrument such as a mobile phone or a personal digital assistance; a disk surface of an optical disk such as Blu-ray disk, DVD disk, CD-R or MO; an optical fiber, and the like.

[0086]

The thickness of the fluorine-containing silane-based coating is not specifically limited. For the optical member, the thickness of the fluorine-containing silane- based coating is within the range of 1-30 nm, preferably 1- 15 nm, in view of optical performance, friction durability and antifouling property.

[0087]

Hereinbefore, the process for producing an article of the present invention and the article produced by the process are described in detail through an embodiment of the present invention, although the embodiment can be variously modified.

[0088] '

For example, though the fluorine-containing silane- based coating is directly on the underlayer in the above embodiment, it may be formed on the underlayer via an inorganic material layer. In the modified embodiment also, because a reactive part is present on the surface of the underlayer (cured coating) , the inorganic material layer has high adherence strength to the underlayer, and the fluorine-containing silane-based coating having high adherence strength to the inorganic material layer can be formed by applying the surface treatment agent comprising a fluorine-containing silane compound to the inorganic material layer. As a result, the fluorine-containing silane-based coating having friction durability can be formed. The inorganic material layer may be a single layer or multi layers. In addition, if necessary, an inorganic material layer having an antireflection function may be used as the inorganic material layer, and either a single antireflection layer or a multi antireflection layer may be used. The inorganic material layer is not specifically limited to, but may be a layer comprising, for example, Si0₂, SiO, Zr0₂, Ti0₂, TiO, Ti₂0₃, Ti₂0₅, Al₂0₃, Ta₂0₅, Ce0₂, MgO, Y₂0₃, Sn0₂, MgF₂, and the like. These inorganic materials may be used alone or in combination with two or more (for example, as a mixture) . When using the multi antireflection layer, preferably, Si0₂ and/or SiO are used in the outermost layer. These layers can be formed by a well-known method such as vapor deposition, sol-gel method or the like. The thickness of the inorganic material layer is not specifically limited to, but may be, for example, within the range of 1 to 300 nm.

[0089]

In addition, for example, in the above embodiment, the composition for forming an underlayer is applied to the surface of the organic base material to form a precursor coating; (when the composition for forming an underlayer is diluted with a solvent, after the solvent is removed) the precursor coating is irradiated with light to complete curing to obtain a cured material as an underlayer,- and then the surface treatment agent comprising a fluorine- containing silane compound is applied to thereon to form the fluorine-containing silane-based coating, though the timing of the formation of the cured coating and the formation of a fluorine-containing silane-based coating is limited thereto. More specifically, the composition for forming an underlayer is applied to the surface of the organic base material to form the precursor coating; the precursor coating (after removing the solvent in the above case) is used as an underlayer, and the surface treatment agent comprising a fluorine-containing silane compound is applied thereon; the precursor coating is irradiated with light via the layer of the surface treatment agent to form the cured coating; thereby the fluorine-containing silane- based coating may be formed from the surface treatment agent comprising a fluorine-containing silane compound on the cured coating. Alternatively, the composition for forming an underlayer is applied to the surface of the organic base material to form the precursor coating; the precursor coating (after removing the solvent in the above case) is irradiated with light to obtain a semi-cured coating in which curing is partially progressed; the semi- cured coating is used as an underlayer, and a surface treatment agent comprising a fluorine-containing silane compound is applied thereon; the semi-cured coating is irradiated with light via the layer of the surface treatment agent to obtain the completely-cured coating; thereby the fluorine-containing silane-based coating may be formed on the cured coating from the surface treatment agent comprising a fluorine-containing silane compound. According to these modified embodiments, because the precursor coating or the semi-cured coating is irradiated with light via the layer of the surface treatment agent to obtain the cured coating, during this, the surface of the coating (including a precursor coating or the state from a semi-cured coating to a cured coating) is hydrophilized by action of the photocatalyst to generate a hydroxyl group and/or a radical on the surface of the coating, and a hydroxyl group or a hydrolyzable group which is bonded to Si in the fluorine-containing silane compound in the surface treatment agent which is contacted with such coating can be readily reacted with the hydroxyl group and/or the radical generated on the surface of the coating, thereby high adherence strength can be obtained between the completely-cured coating and the fluorine-containing silane compound (the inorganic material layer in the above modified embodiment), as a result, the fluorine-containing silane-based coating having high friction durability can be formed .

[0090]

Hereinafter, the process for producing an article of the present invention will be described in detail through Examples, although the present invention is not limited to Examples .

[0091]

Example 1

^• Preparation of a Ti0₂ nanoparticle solution (A-l)

Firstly, titanium diisopropoxide bis (acetylacetonate)

(manufactured by Nippon Soda Co., Ltd.; T-50, titanium oxide-equivalent solid content = 16.5% by weight) (70 g) was dissolved into denatured alcohol (134.9 g) , then, ion- exchanged water (26.0 g) (10 times mole/mole of Ti0₂) was slowly added thereto dropwise with stirring to hydrolyze titanium diisopropoxide bis (acetylacetonate) . After one day, the solution was filtered to obtain 5.0 wt% (titanium oxide-equivalent solid content) of a tan clear Ti0₂ nanoparticle solution (A-l) . This was a hydrolysate of the chelate compound of titanium.

[0092]

Preparation of a composition for forming an underlayer (S-l)

A composition for forming an underlayer (S-l) was prepared by adding the Ti0₂ nanoparticle solution (A-l) (74.0 g) prepared in the above as a photocatalyst to multifunctional acrylic urethane (manufactured by Arakawa Chemical Industries, Ltd.; Beam Set 575 CB) (37.0 g) as a photocurable organic material, vinyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd.; DOW CORNING TORAY SZ6300 SILANE) (18.5 g) and γ- methacryloxypropyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd.; DOW CORNING TORAY SZ6030 SILANE) (18.5 g) as a photocurable organic material and an unsaturated silane compound and methyl isobutyl ketone (46.3 g) as a solvent to prepare a composition for forming an underlayer (S-l) .

[0093]

^• Formation of an underlayer

An acrylic plate (manufactured by Mitsubishi Rayon Co.,

Ltd.; Acrylite, thickness: 1.0 mm) was used as an organic base material. The acrylic plate was treated with the composition for forming an underlayer (S-l) by using Dip Coater (manufactured by SDI Company) (pulling rate: 15 mm/sec). The acrylic plate on which the composition for forming an underlayer was thus coated was dried in the dryer at 60°C for 30 minutes, and then irradiated with ultraviolet (wavelength: 200-400 nm; integral of light: 600 mj/cm²) to form an underlayer (P-l) as a cured coating thereof.

[0094]

^• Formation of an antifouling layer (a fluorine-containing silane-based coating)

A composition which mainly comprises a compound of the following formula (molecular weight: about 4,000) (80 mg) was added to a copper cup, and then the compound was deposited on the surface of the underlayer (P-l) formed in the above by a resistance heating method by using a deposition apparatus (manufactured by Shincron Co., Ltd.) to form a fluorine-containing silane-based coating. Thus, a sample article was produced.

CF₃CF₂CF₂0(CF₂CF₂CF₂0)_nCF₂CF₂(CH₂CH)_mH

Si(OCH₃)₃

wherein: n is an integer from 20 to 30, and m is an integer from 1 to 5.

[0095]

Example 2

Preparation of a composition for forming an underlayer (S-2)

A composition for forming an underlayer (S-2) was prepared by adding the Ti0₂ nanoparticle solution (A-l) (75.0 g) prepared in Example 1 as a photocatalyst to multifunctional acrylic urethane (manufactured by Arakawa Chemical Industries, Ltd.; Beam Set 575 CB) (50.0 g) as a photocurable organic material, vinyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd.; DOW CORNING TORAY SZ6300 SILANE) (12.5 g) and γ- methacryloxypropyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd.; DOW CORNING TORAY SZ6030 SILANE)

(12.5 g) as a photocurable organic material and an unsaturated silane compound, and methyl isobutyl ketone (46.9 g) as a solvent.

[0096]

^■ Formation of an underlayer

The underlayer (P-2) was formed on the surface of the acrylic plate similarly to Example 1 except that the composition for forming an underlayer (S-2) was used in place of the composition for forming an underlayer (S-l) .

[0097]

A fluorine-containing silane-based coating was formed as an antifouling layer similarly to Example 1 except that the compound was deposited on the surface of the underlayer (P-2) in place of the surface of the underlayer (P-l) .

[0098]

Example 3

^• Formation of an underlayer

An underlayer (P-l) was formed on the surface of the acrylic plate similarly to Example 1.

[0099]

· Formation of an inorganic material layer (a silicon dioxide coating)

Silicon dioxide was deposited on the surface of the underlayer (P-l) at 7mm of thickness by and an electron beam method by using a deposition apparatus (manufactured by Shincron Co., Ltd.) to form a. silicon dioxide coating.

[0100]

A fluorine-containing silane-based coating was formed as an antifouling layer similarly to Example 1 except that the compound was deposited on the surface of the silicon dioxide coating in place of the surface of the underlayer (P-l) ·

[0101]

Comparative Example 1

A fluorine-containing silane-based coating was formed as an antifouling layer similarly to Example 1 except that an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd.; Acrylite; thickness: 1.0 mm) was used as an organic base material, and the compound was deposited on the surface of the acrylic plate without forming an underlayer.

[0102]

Comparative Example 2 Formation of an inorganic material layer (a silicon dioxide coating )

An acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd.; Acrylite; thickness: 1.0 mm) was used as an organic base material. Silicon dioxide was deposited on the surface of the acrylic plate at 7mm of thickness by and an electron beam method by using a deposition apparatus (manufactured by Shincron Co., Ltd.) to form a silicon dioxide coating.

[0103]

A fluorine-containing silane-based coating as an antifouling layer was formed similarly to Example 1 except that the compound was deposited on the surface of the silicon dioxide coating in place of the surface of the underlayer (P-l) .

[0104]

Comparative Example 3

· Preparation of a composition for forming an underlayer (S-3)

A composition for forming an underlayer (S-3) was prepared by adding IRGACURE 907 (manufactured by Ciba Specialty Chemicals Inc.) (2.4 g) as a ultraviolet curing initiator to vinyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd.; DOW CORNING TORAY SZ6300 SILANE) (40.0 g) and γ-methacryloxypropyltrimethoxysilane

(manufactured by Dow Corning Toray Co., Ltd.; DOW CORNING TORAY SZ6030 SILANE) (40.0 g) as a photocurable organic material and an unsaturated silane compound and methyl isobutyl ketone (120.0 g) as a solvent.

[0105]

^• Formation of an underlayer

An underlayer (P-3) was formed similarly to Example 1 except that the composition for forming an underlayer (S-3) was used in place of the composition for forming an underlayer (S-l) .

[0106]

^■ Formation of an antifouling layer (a fluorine-containing silane-based coating)

A fluorine-containing silane-based coating as an antifouling layer was formed similarly to Example 1 except that the compound was deposited on the surface of the underlayer (P-3) in place of the surface of the underlayer (P-l) .

[0107]

Comparative Example 4

Preparation of a composition for forming ah underlayer (S-4)

A composition for forming an underlayer (S-4) was prepared by adding the Ti0₂ nanoparticle solution (A-l) prepared in Example 1 (58.0 g) as a photocatalyst to multifunctional acrylic urethane (manufacture by Arakawa Chemical Industries, Ltd.; Beam Set 575CB) (59.0 g) as a photocurable organic material and methyl isobutyl ketone (37.8 g) as a solvent.

[0108]

^• Formation of an underlayer

An underlayer (P-4) was formed similarly to Example 1 except that the composition for forming an underlayer (S-4) was used in place of the composition for forming an underlayer (S-l) .

[0109]

A fluorine-containing silane-based coating as an antifouling layer was formed similarly to Example 1 except that the compound was deposited on the surface of the underlayer (P-4) in place of the surface of underlayer (P- 1) .

[0110]

Evaluation

A static water contact angle of the antifouling layers (the fluorine-containing silane-based coatings) formed in the above Examples and Comparative Examples was measured. The static water contact angle was measured for 1 μΐι of water by using an automated contact angle measuring instrument (manufactured by KYOWA INTERFACE SCIENCE Co., LTD . ) .

[0111]

Assay 1. Initial Evaluation

Firstly, the static water contact angle of the antifouling layer of which the surface had not still contacted with anything after formation thereof was measured (the friction number of times is zero) .

[0112]

Assay 2. Evaluation of friction durability

Then, an eraser friction durability evaluation was performed. Specifically, the sample article on which the antifouling layer was formed was horizontally arranged, and then, an eraser (manufactured by Kokuyo Co., Ltd.; KESHI- 70; flat dimension: 1 cm x 1.6 cm) was contacted with the exposed surface of the antifouling layer and a load of 500 gf was applied thereon. Then, the eraser was shuttled at a rate of 20 mm/second while applying the load. The static water contact angle. (degree) was measured at the time of 50, 100, 250, 500, 750, and 1,000 shuttles. The evaluation was stopped when the measured value of the contact angle became to be less than 100.

[0113] The results of Test Examples 1 and 2 are shown in Table 1 and Fig . 1 . The symbol " - " represents "not measured" .

[0114]

As understood from Table 1 and Fig. 1, the fluorine- containing silane-based coatings in Examples 1-3 of the present invention has higher friction durability in comparison with the fluorine-containing silane-based coatings in Comparative Example 1 wherein the underlayer was not formed, Comparative Example 2 wherein the silicon dioxide coating was formed in place of the underlayer, Comparative Example 3 wherein the underlayer was formed by using the photocatalyst-free composition, and Comparative Example 4 wherein the underlayer was formed by using the unsaturated silane compound- free composition.

Industrial Applicability

[0115]

The present invention is used for surface-treatment of an organic base material, in particular, suitably applied for obtaining an optical member in which high antifouling property and high friction durability are required.

Claims

1. A process for producing an article comprising a fluorine-containing silane-based coating on a coating surface of an organic base material, wherein the process comprises the steps of:

(b) forming a cured coating derived from the precursor coating on the surface of the organic base material by photo- irradiation to the precursor coating,- and

2. The process for producing an article according to claim 1, wherein the unsaturated silane compound is a compound of the following general formula:

wherein: T is a hydroxyl group or a hydrolyzable group;

R¹¹ is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms;

x is an integer from 1 to 3;

R¹² is a divalent organic group; and

y is 0 or 1.

3. The process for producing an article according to claim 1 or 2 , wherein the photocatalyst consists of a metal compound.

4. The process for producing an article according to any one of claims 1-3, wherein the fluorine-containing silane compound has a perfluoropolyether group and a hydroxyl group or a hydrolyzable group which is bonded to Si.

5. The process for producing an article according to claim 4, wherein the fluorine-containing silane compound comprises one or more compounds of any of the following general formulae (la) and (lb) :

■^■■ (1 b)

wherein :

Rf¹ is an alkyl group having 1 to 16 carbon atoms which may or may not be substituted by one or more fluorine atoms ;

d and f are each independently 0 or 1;

e and g are each independently an integer from 0 to 2; m and 1 are each independently an integer from 1 to

10;

X is a hydrogen atom or a halogen atom;

Y is a hydrogen atom or a lower alkyl group;

Z is a fluorine atom or a lower fluoroalkyl group;

T is a hydroxyl group or a hydrolyzable group;

R¹ is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms ; and

n is an integer from 1 to 3.

6. The process for producing an article according to claim 4, wherein the fluorine-containing silane compound comprises one or more compounds of any of the following general formulae (2a) and (2b) :

Rf²-{OC₄F₈)_s:-(OC3F₅)_a-iOC₂F₄)_b-(OCF₂)_c-OCF(CF₂}_d-{CH₂)_h-0^(CH₂)_rSiT_nR²3._n ^■■■ (2a)

Z

R² ₃.J_nSi-{CH₂)_k-0-(CH₂)_r(CF₂)_fCF- X

Z

* -(OC₄F₃)₅-(OC₃F₅)_a-(OC₂F₄)_b-(OCF₂)_c-OCF(CF₂)_d-(CH₂}_h-0-{CH₂)_rSiT_nRVn

^{Z ■■■} (2b)

wherein:

d and f are each independently 0 or 1 ;

h and j are 1 or 2 ; i and k are each independently an integer from 2 to

20;

R² is a hydrogen atom or an alkyl group having 1 to 22 carbon atoms; and

n is an integer from 1 to 3.

7. An article which comprises

an organic base material,

a fluorine-containing silane-based coating formed on the coating.

8. An article which is produced by the process according to any one of claims 1-6.

9. The article according to claim 7 or 8 , wherein the organic base material is clear.

10. The article according to any one of claims 7-9, wherein the fluorine-containing silane-based coating is an antifouling coating.

11. The article according to any one of claims 7-10, wherein the article is an optical member.