JP2003082286A - Thin latex film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To plan to improve, maintain and recover hydrophilic properties of the surface of a member and express self cleaning, easily cleaning, anti- fogging and dew condensation-preventing functions. SOLUTION: This thin latex film is prepared by synthesizing a cross-linked latex polymer from a monomer having a >=4C hydrocarbon group and a fluorinated alkylsulfonic acid-based surfactant and heating the latex polymer at 40-250 deg.C to form the thin latex film having >=65 dyne/cm surface energy.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a highly hydrophilic latex thin film. The present invention also relates to latex polymers useful in making latex thin films and methods of making latex thin films. The present invention also relates to a technique for highly hydrophilicizing the surface of a transparent substrate such as a mirror, a lens, a plate glass or an organic resin thin film with a latex thin film. Furthermore, the present invention also relates to an antifogging technique for preventing fogging of the substrate and formation of water droplets by making the substrate hydrophilic. Furthermore, the present invention provides a technique for preventing surface stains or a technique for self-cleaning (self-cleaning) the surface of a building, a window glass, a mechanical device or an article by making the surface highly hydrophilic. It also relates to a technique for easily cleaning the.

[0002]

2. Description of the Prior Art It is often the case that windshields and windows of automobiles and other vehicles, window glasses of buildings, lenses of spectacles, and cover glasses of various instrument panels become cloudy with condensed moisture during cold weather. In addition, the lenses of mirrors and glasses in bathrooms and washrooms are often fogged by steam. The reason why the surface of the article becomes cloudy is that when the surface is placed at a temperature below the dew point of the atmosphere, moisture in the atmosphere condenses and condenses on the surface. If the condensed water droplets are sufficiently fine and their diameter is about ½ of the wavelength of visible light, the water droplets scatter light, and the glass and mirror become apparently opaque, and the visibility is lost.
If moisture condensation proceeds further and fine condensed water droplets coalesce with each other to grow into larger discrete water droplets, the surface will be shaded due to refraction of light at the water droplet-surface interface and the water-air interface. Blurred, mottled, or cloudy. As a result, the transparent image in a transparent article such as glass is distorted to reduce the transparency, and the reflected image is disturbed in the mirror. Furthermore,
When windshields and windowpanes of vehicles, windowpanes of buildings, rearview mirrors of vehicles, lenses of eyeglasses, shields of masks and helmets are exposed to rain and splashes, and a large number of discrete water droplets adhere to the surface, those surfaces are crusted , Blurry, mottled, or cloudy, again with loss of visibility. As used herein and in the appended claims, the term "anti-fog" broadly refers to the technique of preventing such optical haze, growth of condensed water droplets and optical damage due to water droplet adhesion.

Needless to say, the antifogging technique has a profound effect on safety and efficiency of various operations. For example, if the windshield, window glass, or rearview mirror of a vehicle becomes cloudy or overwhelmed, the safety of the vehicle or traffic will be impaired. Fogging of the endoscopic lens or the dental ophthalmoscope is an obstacle to accurate diagnosis, surgery and treatment.
If the cover glass of the instrument panel becomes cloudy, it will be difficult to read the data. Windshields of automobiles and other vehicles are generally equipped with wipers, defrosting devices, and heaters to ensure visibility in cold weather and in rainy weather. However, it is not commercially feasible to mount these devices on side windows of automobiles or rearview mirrors located outside the automobile. Also,
It is difficult, if not impossible, to attach these anti-fog devices to building window glass or spectacle lenses, endoscopic lenses or dental mirrors, goggles, mask or helmet shields, and instrument panel cover glasses. is there.

As is well known, a simple conventional antifogging method is to apply an antifogging composition containing a hydrophilic compound such as polyethylene glycol or a water repellent compound such as silicone to the surface. Is. However, this kind of anti-fog coating is only temporary and is easily removed by washing or contact with water, and there is a drawback that the effect is lost early. In Japanese Utility Model Publication No. 3-129357 (Mitsubishi Rayon), a polymer layer is provided on the surface of a substrate, and this layer is irradiated with ultraviolet rays and then treated with an alkaline aqueous solution to generate high-density acidic groups. An antifog method for mirrors is disclosed which comprises rendering the surface of the polymer layer hydrophilic. However, even in this method, it is considered that the surface loses hydrophilicity over time due to contaminants attached to the surface, and the antifogging performance is gradually lost. Japanese Utility Model Laid-Open No. 5-68006 (Stanley Electric Co., Ltd.) discloses an antifogging film made of a graft polymer of an acrylic monomer having a hydrophilic group and a monomer having a hydrophobic group. The contact angle of this graft polymer with water is about 50 °, and it is considered that this antifogging film does not have sufficient antifogging performance.

Japanese Unexamined Patent Publication No. 10-156999 (Totoki Co., Ltd.) discloses that when photocatalytic titania is photoexcited, the surface of the photocatalyst is highly hydrophilized, and the surface of the substrate is a wear-resistant photocatalyst made of the photocatalytic semiconductor material. By coating with a hydrophilic coating, "superhydrophilic (superhydrophilicit
y) ”or“ superhydrophilic ”surface is disclosed. The surface superhydrophilization phenomenon caused by photoexcitation of this photocatalyst is not always clearly understood. However, the organic substance adhering to the surface is surely reductively decomposed by the photocatalytic redox reaction, so the binder for coating and maintaining this titania is also attacked by the organic substance.
It is common to coat the titania surface with a silicone polymer. In fact, this has the drawback that the original hydrophilicity of titania is considerably reduced. Kaetsu Isao "Glass Antifogging Coating Technology" (Latest Coating Technology, p. 237-249, Published by General Technology Center, 1986)
Describes various prior art anti-fog techniques. However, the author, Mr. Kaetsu, said that there is a big problem that the antifogging technology by hydrophilization of the surface should be practically overcome, and it is considered that the current antifogging coating technology hits one wall. ing.

On the other hand, in the fields of construction and painting,
Along with environmental pollution, stains on exterior building materials, outdoor structures and their coating films have become a problem. Soot and particles floating in the atmosphere accumulate on the roof and outer walls of buildings in fine weather. The sediment is washed away by rainwater as it rains and flows down the outer wall of the building. Furthermore, in rainy weather, suspended dust is carried by rain and flows down on the outer wall of a building or the surface of an outdoor structure. As a result, contaminants adhere to the surface along the rainwater path. When the surface dries, striped stains appear on the surface. Dirt on building exterior materials and coatings consists of combustion products such as carbon black, urban soot and contaminants of inorganic materials such as clay particles. It is considered that such a variety of pollutants complicates antifouling measures (Yoshinori Tachibana, "Test Method for Accelerating Contamination of Exterior Wall Finishing Materials," Proceedings of Architectural Institute of Japan, No. 404. Issue, October 1989, p. 15
-24). Conventional wisdom believed that water-repellent paints such as polytetrafluoroethylene (PTFE) were preferable to prevent stains on building exteriors, but recently, urban dust containing a large amount of lipophilic components has been considered. It is considered desirable to make the surface of the coating film as hydrophilic as possible (Polymer, Vol. 44, May 1995, p. 30).
7). Therefore, it has been proposed to coat buildings with hydrophilic graft polymers (newspaper "Chemical Industry Daily", 1
January 30, 995). Reportedly, this coating film exhibits hydrophilicity with a contact angle with water of 30 to 40 °. However, the contact angle of inorganic dust represented by clay mineral with water is 20 ° to 50 °, and the contact angle with water has an affinity for the graft polymer having a contact angle of 30-40 ° and adheres to its surface. Since it is easy to do so, it is considered that the coating film of this graft polymer cannot prevent stains due to inorganic dust. Further, conventionally, acrylic resin, acrylic silicone resin, water-based silicone, block polymer of silicone resin and acrylic resin, acrylic styrene resin, sorbitan fatty acid ethylene oxide, sorbitan fatty acid ester, urethane acetate, polycarbonate diol and / or poly Cross-linked urethane of isocyanate,
Various hydrophilic paints composed of a crosslinked polyacrylic acid alkyl ester and the like are commercially available. The contact angle of these hydrophilic paints with water is at most 50 to 70 °, and it is not possible to effectively prevent stains due to urban dust containing a large amount of lipophilic components.

[0007]

The object of the present invention is to provide a mirror,
An object of the present invention is to provide an antifogging method capable of achieving a high degree of visibility of lenses, glass, and other transparent base materials of organic resins. Further, the object of the present invention is to provide a mirror, a lens, a glass,
Another object is to provide an antifogging method capable of maintaining the surface of a transparent base material of an organic resin at a high degree of hydrophilicity for a long period of time. Another object of the present invention is to provide an antifogging coating having excellent durability and abrasion resistance.
Yet another object of the present invention is to provide an anti-fog coating that can be easily and inexpensively applied to surfaces requiring anti-fog. Still another object of the present invention is to
Anti-fog mirrors, lenses that can maintain a high level of hydrophilicity for a long period of time and maintain a high level of anti-fog performance.
A transparent base material of glass and other organic resins, and a method for producing the same.

It is also an object of the present invention to provide a method of rendering the surface of a substrate highly hydrophilic. Another object of the present invention is to make a surface of a building, a window glass, a mechanical device or an article highly hydrophilic so as to prevent the surface from being soiled, or to self-clean the surface (self-cleaning) or easily clean the surface. Is to provide a way to do. Still another object of the present invention is to provide a highly hydrophilic antifouling substrate capable of preventing the surface from being soiled or capable of self-cleaning or easily cleaning the surface and a method for producing the same. Is. Still another object of the present invention is to provide a method of forming a water film on the attached moisture-condensed water to prevent the attached moisture-condensed water from growing into large water droplets by making the surface highly hydrophilic. That is. In some devices, the growth of moisture condensed water adhering to the surface into water droplets impairs its function. For example, in a heat exchanger, when the water droplets attached to the radiation fins grow into large water droplets, the heat exchange efficiency decreases. Still another object of the present invention is to provide a surface-forming composition that highly hydrophilizes the surface of a substrate.

The inventors of the present invention have earnestly studied a method of easily expressing superhydrophilicity by using an organic compound, and as a result,
The present invention has finally been reached. Specifically, it is possible to achieve the object by developing a novel latex polymer and its film-forming technology that develops a mechanism that a surfactant is constantly supplied from the inside of a latex polymer coating. Found.

[0010]

Means for Solving the Problems The present invention includes the following (1) to
(12) A latex thin film, a latex polymer, and a method for producing them are provided. (1) A latex thin film composed of a crosslinked latex polymer and having a surface energy of 65 dyne / cm or more. (2) Made of latex polymer, containing fluoroalkyl sulfonic acid surfactant, surface energy is 65 dy
Latex thin film having ne / cm or more. (3) The latex thin film according to (1) or (2), wherein the polymer has a hydrocarbon group having 4 or more carbon atoms in its side chain.

(4) A latex thin film composed of a latex polymer synthesized from a fluoroalkyl sulfonic acid type surfactant, a monomer having a hydrocarbon group having 4 or more carbon atoms and a cross-linking agent. (5) The latex thin film according to (4), which has a surface energy of 65 dyne / cm or more. (6) Production of a latex polymer comprising a step of emulsifying a monomer having a hydrocarbon group having 4 or more carbon atoms in an aqueous medium containing a fluoroalkylsulfonic acid surfactant, and a step of polymerizing and crosslinking the monomer. Method.

(7) A method for producing a latex thin film, which comprises forming a thin film having a surface energy of 65 dyne / cm or more by heating a thin film of a crosslinked latex polymer at 40 ° C. or higher and 250 ° C. or lower. (8) A latex thin film comprising a cross-linked latex polymer and containing a surfactant, wherein the surfactant leaches from the film to the surface. (9) The latex thin film according to (8), which has a surface energy of 65 dyne / cm or more.

(10) A latex thin film composed of a latex polymer and containing a surfactant, wherein the surfactant is leached from the film through the gaps between the unfused latex particles to the surface of the film to form a surface energy Is 65 dyne / cm
The latex thin film characterized by the above. (11) A latex polymer containing a surfactant, wherein the surfactant is a fluoroalkylsulfonic acid surfactant, and the polymer has a cyclic hydrocarbon group having 6 or more carbon atoms. polymer. (12) The latex polymer according to (11), which is crosslinked.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present specification, a "latex polymer" means a polymer which is dispersed in an aqueous medium in the form of fine particles (in a latex state) or can be dispersed (which can form a latex). . The latex polymer used in the present invention can be prepared by an emulsion polymerization method using a vinyl monomer. The particle size of the polymer particles in the latex is 0.001 to 1 μm
Is preferable, and 0.01 to 0.5 μm is more preferable.

The latex polymer is preferably crosslinked. The crosslinked structure can be introduced into the polymer using a crosslinking agent. As the cross-linking agent, it is preferable to use a monomer having a plurality of polymerizable functional groups. Further, the latex polymer preferably has a hydrocarbon group having 4 or more carbon atoms in the side chain. The number of carbon atoms in the hydrocarbon group is 6
More preferably, it is more preferably 8 or more, still more preferably 10 or more.
"Hydrocarbon group" means an aliphatic group or aromatic group in which only carbon atoms are linked. Aliphatic groups are preferred over aromatic groups, and cycloaliphatic groups are preferred over chained aliphatic groups. A cycloaliphatic group in which a large number of aliphatic rings (eg, cyclopentane ring, cyclohexane ring) are condensed, such as a steroid structure, is most preferable.

The latex polymer is preferably a copolymer having a plurality of repeating units. The latex polymer preferably has (C) a crosslinkable repeating unit, and (A) a strongly hydrophobic repeat unit (non-crosslinkable) having a hydrocarbon group having 10 or more carbon atoms in its side chain or a (B) side. The number of carbon atoms in the hydrocarbon group contained in the chain is 1
9 to 9 or more preferably a weak hydrophobic or hydrophilic repeating unit having no side chain containing a hydrocarbon group (non-crosslinkable) and a crosslinkable repeating unit (C), and (A) strongly hydrophobic. It is more preferable to have a repeating unit and (C) a crosslinkable repeating unit, and to have (A) a strongly hydrophobic repeating unit, (B) a weakly hydrophobic or hydrophilic repeating unit, and (C) a crosslinking repeating unit. Most preferred.

(A) The strongly hydrophobic repeating unit (non-crosslinkable) having a hydrocarbon group having 10 or more carbon atoms in its side chain is:
In the main chain unit (usually ethylene or propylene unit),
A hydrocarbon group having 10 or more carbon atoms is optionally bonded via a linking group. As described above, the hydrocarbon group having 10 or more carbon atoms is preferably an aliphatic group rather than an aromatic group, more preferably a cyclic aliphatic group rather than a chain aliphatic group, and has a large number of aliphatic groups. Most preferred are cycloaliphatic groups in which the rings are fused. The main chain and the hydrocarbon group are preferably bonded via a linking group. The linking group is -CO-, -O.
-, -NH-, an alkylene group and a combination thereof are preferable, and examples of the linking group composed of the combination include a main chain -CO-O- hydrocarbon group and a main chain -CO-O-.
An alkylene group-O-hydrocarbon group, a main chain-CO-O-alkylene group-O-alkylene group-O-hydrocarbon group and a main chain-CO-NH-hydrocarbon group are included.

The ratio of the (A) strongly hydrophobic repeating unit (the ratio in the monomer mixture before synthesis) in the latex polymer is preferably 5 to 85% by mass.
To 80% by mass, more preferably 15 to 7
It is more preferably 5% by mass, and most preferably 20 to 70% by mass. (A) The strongly hydrophobic repeating unit includes an alkyl acrylate (eg, n-dodecyl acrylate), a substituted alkyl acrylate (eg, cholesteryl acrylate, cholesteryl diethylenedioxy acrylate), an alkyl methacrylate (eg, n-dodecyl methacrylate), a substituted alkyl. Methacrylate (eg, cholesteryl methacrylate, cholesteryl diethylenedioxymethacrylate) or styrene derivative (eg, vinylnaphthalene)
Can be introduced into the latex polymer by using as a monomer. Hereinafter, examples of (A) a strongly hydrophobic repeating unit (non-crosslinking) having a hydrocarbon group having 10 or more carbon atoms in its side chain will be given.

[0019]

[Chemical 1]

[0020]

[Chemical 2]

[0021]

[Chemical 3]

[0022]

[Chemical 4]

[0023]

[Chemical 5]

(B) The weakly hydrophobic or hydrophilic repeating unit in which the number of carbon atoms of the hydrocarbon group contained in the side chain is 1 to 9 or there is no side chain containing the hydrocarbon group (non-crosslinking) is It is preferable that a hydrocarbon group having 1 to 9 carbon atoms is bonded to a main chain unit (usually an ethylene or propylene unit), optionally via a linking group. The hydrocarbon group having 1 to 9 carbon atoms is preferably an aliphatic group rather than an aromatic group, more preferably a chain aliphatic group rather than a cycloaliphatic group, and has a branched chain aliphatic compound. A straight-chain aliphatic group is more preferable than a straight-chain aliphatic group. The main chain and the hydrocarbon group are preferably bonded via a linking group. The linking group is -CO-,-
Examples of the linking group consisting of O-, -NH-, an alkylene group, and a combination thereof are preferably a main chain-CO-O-hydrocarbon group and a main chain-CO-O.
-Alkylene group-O-hydrocarbon group, main chain-CO-O-alkylene group-O-alkylene group-O-hydrocarbon group and main chain-CO-NH-hydrocarbon group are included. The ratio of the (B) weakly hydrophobic or hydrophilic repeating unit (the ratio in the monomer mixture before synthesis) in the latex polymer is 1
It is preferably from 5 to 95% by mass, and from 20 to 90
More preferably, it is 25 to 85% by mass.
Is more preferable, and 30 to 80% by mass is the most preferable.

(B) Weakly hydrophobic or hydrophilic repeating units include olefin, unsaturated carboxylic acid, alkyl acrylate, substituted alkyl acrylate, alkyl methacrylate, substituted alkyl methacrylate, unsaturated dicarboxylic acid ester, unsaturated carboxylic acid amide, styrene. , Styrene derivatives, vinyl ethers, vinyl esters or other vinyl compounds can be used as monomers to be incorporated into the latex polymer. Examples of olefins include ethylene, propylene, vinyl chloride, vinylidene chloride, 6-hydroxy-1-hexene, 4-pentenoic acid, methyl 8-nonenate, vinyl sulfonic acid, trimethylvinylsilane, trimethoxyvinylsilane. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, sodium acrylate, ammonium methacrylate, potassium itaconate.

Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, n-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate. Examples of substituted alkyl acrylates include 2-chloroethyl acrylate, benzyl acrylate, 2-cyanoethyl acrylate. Examples of alkyl methacrylates include methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate. Examples of substituted alkyl methacrylates include 2-hydroxyethyl methacrylate,
Glycidyl methacrylate, glycerin monomethacrylate, 2-acetoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 2-methoxyethyl methacrylate, ω-methoxypolyethylene glycol methacrylate (addition mole number of polyoxyethylene: 2
100), polyethylene glycol monomethacrylate (polyoxyethylene addition mole number: 2 to 100), polypropylene glycol monomethacrylate (polyoxypropylene addition mole number: 2 to 100), 2-carboxyethyl methacrylate, 3-sulfopropyl methacrylate. , 4-oxysulfobutyl methacrylate, 3
-Includes trimethoxysilylpropyl methacrylate.

Examples of unsaturated dicarboxylic acid esters include monobutyl maleate, dimethyl maleate, monomethyl itaconate, dibutyl itaconate. Examples of unsaturated carboxylic acid amides are acrylamide, methacrylamide, N-methyl acrylamide, N, N-dimethyl acrylamide, N-methyl-N-hydroxyethyl acrylamide, N-tert butyl acrylamide, N.
-Tert-octylmethacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide, N-
(2-acetoacetoxyethyl) acrylamide, N-
Acryloylmorpholine, diacetone acrylamide, itaconic acid diamide, N-methylmaleimide, 2-
Acrylamide-2-methylpropane sulfonic acid is included. Examples of styrene derivatives include vinyltoluene, p-
tert-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, p-hydroxymethyl styrene, p-styrene sulfonic acid sodium salt, p-styrene sulfinic acid potassium salt are included. Examples of vinyl ethers include methyl vinyl ether, butyl vinyl ether, methoxyethyl vinyl ether. Examples of vinyl esters include
Includes vinyl acetate, vinyl propionate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate. Examples of other vinyl compounds include N-vinylpyrrolidone and 2
-Includes vinyl oxazoline and 2-isopropenyl oxazoline. Examples of (B) weakly hydrophobic or hydrophilic repeating units in which the number of carbon atoms of the hydrocarbon group contained in the side chain is 1 to 9 or there is no side chain containing the hydrocarbon group (non-crosslinkable) I will give you.

[0028]

[Chemical 6]

[0029]

[Chemical 7]

[0030]

[Chemical 8]

[0031]

[Chemical 9]

[0032]

[Chemical 10]

[0033]

[Chemical 11]

[0034]

[Chemical 12]

[0035]

[Chemical 13]

[0036]

[Chemical 14]

[0037]

[Chemical 15]

[0038]

[Chemical 16]

[0039]

[Chemical 17]

[0040]

[Chemical 18]

[0041]

[Chemical 19]

[0042]

[Chemical 20]

The crosslinkable repeating unit (C) has a structure in which a plurality of main chain units (usually ethylene or propylene units) are bonded via a linking group. The linking group that bonds the main chain is preferably —CO—, —O—, —NH—, —SO ₂ —, a hydrocarbon group, a heterocyclic group, or a combination thereof. The proportion of the (C) crosslinkable repeating unit in the latex polymer (the proportion in the monomer mixture before synthesis) is preferably from 0 to 15% by mass.
To 10% by mass, more preferably 1.5 to 8% by mass, further preferably 2 to 7% by mass.
Is most preferable.

The crosslinkable repeating unit (C) is an olefin (eg, isoprene, butadiene, cyclopentadiene,
Pentadiene, 1,4-divinylcyclohexane, 1,
2,5-trivinylcyclohexane), acrylic acid ester (eg, allyl acrylate), methacrylic acid ester (eg, allyl methacrylate), ester of polyhydric alcohol and unsaturated fatty acid (eg, ethylene glycol diacrylate, ethylene glycol di) Methacrylate,
1,4-cyclohexanediacrylate, pentaerythritol tetramethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, 1,2,4,5- Cyclohexanetetramethacrylate), unsaturated carboxylic acid amides (eg, methylenebisacrylamide, dimethacryloylpiperazine), styrene derivatives (eg, 1,4-
It can be introduced into the latex polymer by using divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester) or other vinyl compound (eg, divinylsulfone) as a monomer. less than,
Examples of the crosslinkable repeating unit (C) are given below.

[0045]

[Chemical 21]

[0046]

[Chemical formula 22]

[0047]

[Chemical formula 23]

[0048]

[Chemical formula 24]

[0049]

[Chemical 25]

[0050]

[Chemical formula 26]

Specific examples of the latex polymer will be given below. The ratio of each repeating unit is% by mass in the monomer mixture before synthesis. (1)-(A-1) 33-(B-1) 64--
(C-1) 3- (2)-(A-1) 33-(B-1) 61 ---
(C-1) 6- (3)-(A-1) 38-(B-2) 59 ---
(C-1) 3- (4)-(A-1) 33-(B-3) 64 ---
(C-1) 3- (5)-(A-1) 63-(B-1) 34 ---
(C-1) 3- (6)-(A-1) 23-(B-4) 71 ---
(C-1) 6- (7)-(A-1) 38-(B-5) 59 ---
(C-1) 3- (8)-(A-1) 33-(B-6) 64 ---
(C-1) 3- (9)-(A-2) 63-(B-1) 34 ---
(C-1) 3- (10)-(A-3) 23-(B-7) 71-
-(C-1) 6- (11)-(A-4) 38-(B-5) 59-
-(C-1) 3- (12)-(A-5) 38-(B-6) 64-
-(C-1) 3- (13)-(A-6) 63-(B-1) 34-
-(C-1) 3- (14)-(A-7) 23-(B-7) 71-
-(C-1) 3- (15)-(A-8) 38-(B-5) 59-
-(C-1) 3- (16)-(A-9) 38-(B-6) 64-
-(C-1) 3-

Two or more kinds of latex polymers may be used in combination. The molecular weight of the latex polymer is preferably 100,000 or more. The latex polymer is preferably synthesized using an emulsion polymerization method. Using the emulsion polymerization method, a polymer having a higher molecular weight (usually a weight average molecular weight of 100,000 or more) can be synthesized without using a chain transfer agent as compared with a usual synthesis method (eg, solution polymerization method). . When the crosslinkable repeating unit (C) is introduced, the molecular weight of the polymer may be substantially infinite.

In the emulsion polymerization method, the monomer is emulsified in an aqueous solvent using an emulsifier, and then the monomer is polymerized by stirring with a radical polymerization initiator. The aqueous solvent is
It is water or a mixed solvent of water and an organic solvent miscible with water. Examples of water-miscible organic solvents are methanol,
Includes ethanol and acetone. The amount of the organic solvent miscible with water is preferably 100% or less and more preferably 50% or less by volume with respect to water. The amount of the monomer used is 5 to 1 with respect to the aqueous solvent.
It is preferably 50% by mass. The amount of emulsifier used is
It is preferably 0.1 to 20 mass% with respect to the monomer. The amount of radical polymerization initiator used is preferably 0.02 to 5 mass% with respect to the monomer. The temperature of the polymerization reaction is preferably 30 ° C to 100 ° C, more preferably 40 ° C to 90 ° C.

The radical polymerization initiator is a peroxide,
Azobis compounds, hydroperoxides or redox catalysts can be used. Examples of inorganic peroxides include potassium persulfate and ammonium persulfate.
Examples of organic peroxides include t-butyl peroctoate,
Benzoyl peroxide, isopropyl percarbonate, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, and dicumyl peroxide are included. Examples of azobis compounds include 2,2′-azobisisobutyrate, sodium salt of 2,2′-azobiscyanovaleric acid,
2,2'-azobis (2-amidinopropane) hydrochloride, 2,2'-azobis [2- (5-methyl-
2-imidazolin-2-yl) propane] hydrochloride, 2,
2'-azobis {2-methyl-N- [1,1'-bis (hydroxymethyl) -2-hydroxyethyl] propionamide} is included. Inorganic peroxides are preferred, potassium persulfate and ammonium persulfate being especially preferred.

As the emulsifier, an anionic surfactant,
A cationic surfactant, an amphoteric surfactant, a nonionic surfactant or a water-soluble polymer can be used. Examples of the emulsifier include sodium laurate, sodium dodecyl sulfate, sodium 1-octyloxycarbonylmethyl-1-octyloxycarbonylmethanesulfonate, sodium laurylnaphthalenesulfonate, sodium laurylbenzenesulfonate, sodium laurylphosphate, cetyltrimethyl. Included are ammonium chloride, N-2-ethylpyridinium chloride, polyoxyethylene nonylphenyl ether, polyoxyethylene sorbitan lauryl ester, polyvinyl alcohol, fluorinated alkyl sulfonic acids and polyoxyethylene polyfluorinated alkyl esters. For the emulsifier used in the synthesis of latex polymer, see Japanese Examined Patent Publication Sho 53
It is also described in Japanese Patent No. 6190.

In the present invention, it is particularly preferable to use a fluorine-containing surfactant. The fluorinated surfactant is a surfactant containing a fluorine atom in the hydrophobic group. Examples of the hydrophobic group containing a fluorine atom include a fluoroalkyl group, a fluoroalkenyl group and a fluoroaryl group. Fluoroalkyl groups are preferred. Examples of the hydrophilic group of the fluorine-containing surfactant include an anion group (eg, sulfonic acid group, sulfuric acid ester group, carboxylic acid group, phosphoric acid group), cation group (eg, aliphatic amino group, ammonium group, aromatic group). Group amino group, sulfonium group, phosphonium group) and nonionic group (eg, polyoxyalkylene group, polyglyceryl group,
Sorbitan group) is included. The anion group and the cation group may be in a salt state. The polyoxyalkylene group may have a substituent. A bedaine group having both an anion group and a cation group (eg, carboxylamine salt, carboxylammonium salt, sulfoamine salt, sulfoammonium salt, phosphoammonium salt) can also be used as the hydrophilic group. Anionic groups are preferred and sulphonic acid groups are particularly preferred.

The fluorine-containing surfactant is described in JP-A-4
9-10722, 55-149938, 58-
196544 publications, British patent 1330356,
No. 1417915, No. 1439402, US Patent No. 4
There is a description in each specification of No. 335201. Below, the example of a fluorine-containing surfactant is shown.

[0058]

[Chemical 27]

In emulsion polymerization, the polymerization initiator, concentration,
Control the polymerization temperature and reaction time. The emulsion polymerization reaction is
It is possible to carry out by putting all of the monomers, the surfactant and the aqueous medium in the reaction vessel in advance and then adding the polymerization initiator.
It is also possible to add either one or both of the monomer and the initiator solution while dropping them. The latex polymer can be easily synthesized by using a general emulsion polymerization method. For general emulsion polymerization methods, see "Synthetic Resin Emulsion (edited by Okudadaira, Hiroshi Inagaki, published by Kobunshi Kogakukai (1971).
8)) ”,“ Application of synthetic latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, published by Kobunshi Kogyokai (19)
93)) "and" Chemistry of Synthetic Latex (Soichi Muroi, published by Kobunshi Kogakukai (1970)) ".

In the present invention, the surface energy of the latex thin film can be 65 dyne / cm or more.
The surface energy of 65 dyne / cm or more means
It means that it has a high degree of hydrophilicity (that is, wettability) of 10 ° or less (preferably 5 ° or less) in terms of contact angle with water. The term "superhydrophilicity" or "superhydrophilic" is used to indicate such surface phenomena or physical properties.

A water-soluble substance such as a sulfo group-containing dye, a water-soluble lubricant, a water-soluble physiologically active substance, a proton-transportable organic sulfonic acid-based polymer, or a water-soluble photograph is added to the crosslinked latex polymer suspension. A useful thin substance, for example, a development accelerator, a development inhibitor, an antifoggant, and a fogging agent may be added to cause a fusion between latex particles with heating or aging to form a thin film.

The latex thin film is formed by applying a suspension of latex polymer particles onto a support and heating. As the support, generally, for example, metals such as copper, iron, silicon and titanium, glass, various ceramics, carbon such as graphite, polyethylene, polyphenol, polypropylene, ABS polymer,
Epoxy resin, glass fiber reinforced epoxy resin, polyester, polyamide, polyimide, polyarylate, polycarbonate, polysulfone, polyolefin, polyacrylonitrile, polyvinyl halide, cellulose triacetate, cotton or wool or a mixture thereof, or a mixture of the above monomers. Examples include polymer woven sheets, fibers such as yarns, aggregates of fibers such as paper, and particles such as silica gel, alumina, and titanium oxide.

As a coating method, spray coating,
A coating method such as flow coating, spin coating, dip coating, roll coating or bar coating can be used. The thickness of the latex thin film is preferably 0.1 to 20 μm, more preferably 0.5 to 5 μm. The heating temperature and time mainly depend on the strength of the thin film, which depends on the progress of the fusion process of the latex polymer. Preferably 40 ° C
Or more and 250 ° C or less, more preferably 120 ° C or more and 200 ° C or less. This heating time is preferably 1 minute to 2 hours.

The mechanism by which the thin film made of the latex polymer exhibits superhydrophilicity is not necessarily clear, but the surfactant on the surface of the latex particles inside gradually penetrates through the gaps between the latex polymer particles which are not completely fused. It is presumed that it has super-hydrophilicity apparently because it leaches out to the surface and is always covered with a surfactant. Therefore, it is preferable that the surfactant used in the emulsification process for forming the latex is not compatible with the latex polymer produced. When the fluorine-containing surfactant is used, it is preferable that the monomer constituting the latex has a long chain alkyl group or an alicyclic group such as cholesteryl group. When the surfactant has an alkyl group having a large number of carbon atoms, the latex preferably comprises a fluoropolymer or a siloxane polymer. That is, since the hydrocarbon compound (eg, alkane, alkene) and the fluorine-containing compound or the silicon-containing compound are incompatible with each other, the relationship between them is used to form the monomer forming the surfactant and the latex. Can be configured so as not to be compatible with each other.

Once the surface of the coating is highly hydrophilized, the hydrophilicity of the surface will persist, even if the substrate is kept in the dark. When contaminants are adsorbed on the surface hydroxyl groups with the passage of time and the surface gradually loses its superhydrophilicity, the superhydrophilicity is restored by washing with water and heating again.

Such superhydrophilic surface can be applied to various uses. In one aspect of the present invention, the present invention is an antifogging method for a transparent member, an antifogging transparent member, and
The manufacturing method is provided. According to the present invention, a transparent member coated with a coating in advance is prepared, or the surface of the transparent member is coated with the coating. Transparent members include rearview mirrors for vehicles, mirrors for bathrooms or washrooms, dental tooth mirrors, mirrors such as road mirrors; lenses such as eyeglass lenses, optical lenses, camera lenses, endoscope lenses, and illumination lenses. Prisms; window glass for buildings and surveillance towers; automobiles, railway vehicles, aircraft, ships, submarines, snow vehicles, ropeway gondolas, amusement park gondolas, vehicle windows such as spaceships; automobiles, rail vehicles, Aircraft, ships,
Windshields for vehicles such as submersibles, snowmobiles, snowmobiles, motorcycles, ropeway gondolas, amusement park gondolas, spaceships; shields for protective or sports goggles or masks (including diving masks); helmets Shield; glass for frozen food display case; cover glass for measuring equipment. When the surface of the coating is made superhydrophilic, even if moisture or steam in the air condenses, the condensed water becomes a uniform water film without forming individual water droplets, so the surface has light-scattering cloudiness. Does not occur. Similarly, even when the window glass, the vehicle rearview mirror, the vehicle windshield, the eyeglass lens, and the helmet shield are exposed to rain or splashes, the water droplets adhering to the surface quickly spread to a uniform water film.
No discrete annoying water droplets are formed. Therefore, a high degree of visibility and visibility can be ensured, the safety of vehicles and traffic can be guaranteed, and the efficiency of various work and activities can be improved.

In another aspect of the invention, the invention comprises:
Provided are a method of self-cleaning (self-cleaning) the surface of a base material by rainfall by making the surface of the base material superhydrophilic, a self-cleaning base material, and a method for producing the same. The base material is, for example, metal, ceramics, glass, plastics, wood, stone, cement, concrete, a combination thereof, a laminate thereof, or a building exterior formed of another material, a window frame, a structural member, Window glass; car,
Includes exteriors and coatings for vehicles such as railway cars, aircraft, and ships; exteriors and coatings for machinery and goods, dust-proof covers and coatings; traffic signs, various display devices, exteriors and coatings for advertising towers. The surface of the substrate is coated with a coating. Mechanical devices and articles located in buildings and outdoors are exposed to sunlight during the day, so the surface of the coating is highly hydrophilized. Moreover, the surface is occasionally exposed to rainfall. Every time the superhydrophilized surface receives rainfall, soot and contaminants adhering to the surface of the substrate are washed away by raindrops, and the surface is self-cleaned. The surface of the coating is highly hydrophilized so that the contact angle with water is 10 ° or less, preferably 5 ° or less, and particularly about 0 °, so that not only urban dust containing a large amount of lipophilic components but also clay minerals can be used. Inorganic dust such as is easily washed off the surface. In this way, the surface of the substrate is highly self-cleaned and kept clean by the action of nature. For example, the glass-wiping work in high-rise buildings is no longer necessary or can be substantially eliminated.

In yet another aspect of the present invention, the present invention provides a coating on the surface of a building, a window glass, a mechanical device or an article, and makes the surface highly hydrophilic to prevent the surface from being soiled. Provide a way. The superhydrophilized surface prevents contaminants from adhering to the surface when rainwater entrained with contaminants such as dust suspended in the atmosphere flows down. Therefore, in combination with the self-cleaning action due to the rainfall mentioned above, the surface of a building or the like is maintained almost permanently and highly cleanly.

In another aspect of the invention, a device or article formed of metal, ceramics, glass, plastics, wood, stone, cement, concrete, combinations thereof, or laminates thereof (eg, for building). Exterior, building interior materials, window glass, housing equipment, toilet bowl, bathtub,
The surface of wash basins, lighting fixtures, kitchen utensils, dishes, sinks, stoves, kitchen hoods, ventilation fans) is coated with a coating and these oily or fat-contaminated articles are dipped in water, wetted with water or washed with water. Upon rinsing with, oil stains are released from the surface of the superhydrophilized coating and are easily removed. For example, dishes soiled with oil or fat can be washed without the use of detergent.

In another aspect of the invention, the invention comprises
A method for preventing the growth of water droplets attached to a substrate or spreading the attached water droplets on a uniform water film is provided. Therefore, the surface of the substrate is covered with the coating. When the surface is made superhydrophilic by coating, the moisture-condensed water or water droplets adhering to the surface of the substrate spreads on the surface to form a uniform water film. When this method is applied to the heat radiating fins of a heat exchanger, for example, the passage of the heat exchange medium is prevented from being clogged with condensed water,
The heat exchange efficiency can be increased. Alternatively, if this method is applied to a mirror, a lens, a window glass, a windshield, and a pavement, it is possible to accelerate the drying of the surface after being wet with water.

[0071]

[Example] [Synthesis example 1] Synthesis of compound (A-1a)

[0072]

[Chemical 28]

In a 500 mL glass container, 106.1 g of diethylene glycol, 100 mL of THF, 8.9 m
L pyridine was charged. To this, a solution of 44.9 g of cholesteryl chloroformate dissolved in 100 mL of THF was slowly added. The mixture was stirred at room temperature for 30 minutes and further at 70 ° C. for 3 hours. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The extract was further washed with saturated brine and dried over anhydrous sodium sulfate. The ethyl acetate was distilled off under reduced pressure to obtain 48.7 g of a waxy crude compound (A-1a). ¹ H-NMR (CDCl ₃ ): δ (ppm) = 0.7-
2.4 (m, 43H), 3.6 (t, 2H), 3.75
(T, 4H), 4.3 (t, 2H), 4.5 (m, 1
H), 5.4 (d, 1H)

Synthesis of compound (A-1b)

[0075]

[Chemical 29]

In a 500 mL glass container, the compound (A-1
a) 46.1 g, 200 mL THF and 20.3 m
L of dimethylaniline was added. To this, 13.0mL
Was slowly added at 60 ° C., and the mixture was further stirred for 2 hours. The reaction mixture was poured into water, extracted with ethyl acetate, and dried over anhydrous sodium sulfate. The ethyl acetate was distilled off under reduced pressure, to which 150 mL of DMAc, 20
mL triethylamine and 0.5 mL nitrobenzene were added, and the mixture was stirred at 60 ° C. for 3 hours. Once again, the reaction mixture was poured into water, extracted with ethyl acetate and dried over anhydrous sodium sulfate. Ethyl acetate was distilled off under reduced pressure, and 52.0
g of crude compound (A-1b) was obtained. This was purified by silica gel column chromatography (developing solvent; n-hexane / ethyl acetate = 5: 1), and 47.8 g of the compound (A
-1b) was obtained. ¹ H-NMR (CDCl ₃ ): δ (ppm) = 0.7-
2.4 (m, 43H), 3.7 (m, 4H), 4.3
(M, 4H), 4.5 (m, 1H), 5.4 (d, 1
H), 5.85 (d, 1H), 6.15 (dd, 1)
H), 6.45 (d, 1H)

Synthesis of latex polymer (1)

[0078]

[Chemical 30]

52 mL of water and 232 mg of the following surfactant (S) were placed in a 100 mL glass container, and the inside of the container was replaced with nitrogen for 1 hour. 4. Heat the container to 80 ° C and
4 mg 2-butanone and 46.3 mg ammonium persulfate dissolved in 1 mL water were added. While stirring this solution, the compound (A-1b) 2.2 was added therein.
A mixture of 9 g, butyl acrylate 0.979 g, divinylbenzene 47 mg and 2-butanone 24 mL was added over 4 hours. After flowing nitrogen into the reaction vessel for 30 minutes, the mixture was cooled to room temperature and filtered, and then the latex polymer (1) was used.
45.5 g of an aqueous solution of (Solid content concentration 5.13 wt
%, Solid content yield 64.9%)

[0080]

[Chemical 31]

Example 1 Preparation of Latex Thin Film A suspension of latex polymer (1) was filtered with a 5 μm filter and bar-coated on a glass plate.
After heating it at 200 ° C. for 30 minutes, it was cooled, immersed in water for 30 minutes, allowed to stand, and further dried at 80 ° C. for 20 minutes to obtain a latex thin film. The film thickness is 1.64 μm,
The surface energy was 75.0 dyne / cm. In addition, the contact angle of the surface of this sample with water is measured by a contact angle measuring instrument (ERMA, type GI-1000, low angle side detection limit 3 °).
The contact angle reading was less than 1 °.

[Example 2] Relationship between surface energy by repeated washing with water and elemental analysis values of the surface A latex thin film was prepared in the same manner as in Example 1 except that the glass plate was a polyimide film having a thickness of 50 µm. . The film thickness was 1.33 μm, and the surface energy was 73.0 dyne / cm. The contact angle of the surface of this thin film with water was measured with a contact angle measuring instrument (Model GI-1000, manufactured by ERMA, detection limit 3 ° on the low angle side), and the reading of the contact angle was less than 1 °. It was XPS (Shimadzu Electron Spectromet)
er: ESCA-750). The results are shown in Table 1. In the latex thin film, only the surfactant (S) contains fluorine and sulfur elements. By comparing the theoretical element ratio of F / C and the elemental analysis value of the surface, it was strongly suggested that the surfactant or the compound derived therefrom was segregated at a considerably high concentration on the surface of the latex thin film. . However, the presence of a water-repellent fluorinated alkyl group markedly reduces the surface energy significantly, and it has a thermophysical property that does not easily decompose under the film forming conditions. The surfactant (S) itself believes that the surfactant (S) is deposited on this surface.

Next, the latex thin film is immersed in water for 30 minutes, and the surfactant (S) present on (or will be on) the surface.
Was attempted to be washed and removed. Even after 30 washings with water, the elemental concentrations of fluorine and sulfur on the surface remained high, and the surface energy remained high. However, it was found that after washing 100 times with water, both the F / C and S / C ratios decreased and the surface energy also decreased. This experimental fact suggests that the surfactant (S) segregates on the surface and continuously leaches on the surface even after washing with water, and at the same time, the supply capacity thereof has a limit value. However,
Immersion in water for 30 minutes × 100 times is a very harsh condition, which also suggests high durability of the latex thin film.

[0084]

[Table 1]

Example 3 Preparation of Anti-fog Mirror A mirror was manufactured by forming a reflective coating of aluminum on the back surface of the glass plate of Example 1 by vacuum vapor deposition to prepare Sample # 1.
Got Sample # 1 was left outdoors for 8 days, then allowed to stand in water for 30 minutes, air-dried, and then heated at 70 ° C. for 30 minutes to obtain sample # 2. For comparison, a glass plate not coated with the latex of the present invention was designated as sample # 3. Sample # 2
And the contact angle of Sample # 3 with water were measured by a contact angle measuring instrument (CA-X150, manufactured by Kyowa Interface Science Co., Ltd., Asaka City, Saitama Prefecture).
The detection limit on the low angle side of this contact angle measuring device was 3 °.
The contact angle was measured 30 seconds after a water droplet was dropped from the microsyringe on the sample surface. The measuring instrument readings of water on the surfaces of Samples # 1 and # 2 were both 0 °, indicating superhydrophilicity. On the other hand, the contact angle of # 3 sample with water is 30-
It was 40 °. Next, regarding sample # 2 and sample # 3,
The antifogging property and the spread of the adhered water drops were evaluated. Anti-fogging property is evaluated by adding a beaker of 500 mL with hot water of about 80 ° C for 300 m.
The sample was held for about 10 seconds on the beaker with the surface of the mirror facing downward, and immediately after that, the presence or absence of fogging on the sample surface and the appearance of the tester's face were evaluated. In Sample # 3, the surface of the mirror was clouded by steam and the image of the tester's face was not well displayed, but in Sample # 2, no cloudiness was observed and the tester's face was clearly reflected. Evaluation of the spread state of water droplets
A large number of water drops were dropped from the upper side onto the surface of the mirror inclined at 45 °, and the state of water drop adhesion after the mirror was once vertical and the appearance of the tester's face were evaluated. In the sample # 3, distracting isolated water droplets were attached to the surface of the mirror, and the reflection image was disturbed by the refraction of light by the water droplet, and it was difficult to clearly observe the reflection image. On the other hand, in sample # 2, the water droplets attached to the surface of the mirror spread on the surface without forming isolated water droplets and formed a uniform water film. Although some distortion was observed in the reflection image due to the presence of the water film, the reflection image of the tester's face could be recognized sufficiently clearly.

[0086]

EFFECT OF THE INVENTION By using a novel latex polymer and its film-forming technology, which develops a mechanism in which the surfactant is constantly supplied from the inside of the latex polymer coating of the present invention, the substrate interface Further, the superhydrophilic interface can be easily provided at low cost. INDUSTRIAL APPLICABILITY The latex polymer of the present invention makes it possible to supply a novel high-performance superhydrophilic interface and has an extremely high industrial value.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 7/12 C09D 7/12 201/02 201/02 // C08L 101: 00 C08L 101: 00 (72) Inventor Shigeki Yokoyama 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture, Fuji Photo Film Co., Ltd. F-term (reference) 4F006 AA02 AA12 AA13 AA16 AA17 AA33 AA34 AA35 AA36 AA38 AA39 AA40 AB24 BA10 CA04 CA1 4J011 AA05 CB1 CB06 CB1 061 0381 CE051 CF051 CF091 CG021 CG091 CG141 CG151 CG171 CH031 CH041 CH071 CH081 CH121 CH141 CH171 CH191 CH241 CJ011 CJ061 CJ071 CJ131 CJ181 CK031 DB221 DL111 KA09 LA02 MA14 NA05 NA06 NA11 PB02 PB05 PB07

Claims (12)

[Claims] 1. A latex thin film comprising a cross-linked latex polymer and having a surface energy of 65 dyne / cm or more. 2. A latex thin film comprising a latex polymer, containing a fluoroalkyl sulfonic acid surfactant, and having a surface energy of 65 dyne / cm or more. 3. The latex thin film according to claim 1, wherein the polymer has a hydrocarbon group having 4 or more carbon atoms in its side chain. 4. A latex thin film comprising a latex polymer synthesized from a fluorinated alkyl sulfonic acid type surfactant, a monomer having a hydrocarbon group having 4 or more carbon atoms and a cross-linking agent. 5. The latex thin film according to claim 4, which has a surface energy of 65 dyne / cm or more. 6. A latex polymer comprising a step of emulsifying a monomer having a hydrocarbon group having 4 or more carbon atoms in an aqueous medium containing a fluoroalkylsulfonic acid surfactant, and a step of polymerizing and crosslinking the monomer. Manufacturing method. 7. A method for producing a latex thin film, which comprises forming a thin film having a surface energy of 65 dyne / cm or more by heating a thin film made of a crosslinked latex polymer at 40 ° C. or higher and 250 ° C. or lower. 8. A latex thin film comprising a cross-linked latex polymer and containing a surfactant, wherein the surfactant leaches from the inside of the film to the surface. 9. The latex thin film according to claim 8, which has a surface energy of 65 dyne / cm or more. 10. A latex thin film comprising a latex polymer and containing a surfactant, wherein the surfactant leaches from the film through the gaps between the unfused latex particles onto the film surface, and the surface energy is A latex thin film having a density of 65 dyne / cm or more. 11. A latex polymer containing a surfactant, wherein the surfactant is a fluorinated alkyl sulfonic acid surfactant, and the polymer has a cyclic hydrocarbon group having 6 or more carbon atoms. Latex polymer to do. 12. The latex polymer according to claim 11, which is crosslinked.