CA1216695A

CA1216695A - Hydrophilic-film-forming preparation

Info

Publication number: CA1216695A
Application number: CA000467532A
Authority: CA
Inventors: Tooru Ishii; Yoshihisa Noyoda; Masashi Isobe
Original assignee: Nippon Light Metal Co Ltd
Current assignee: Nippon Light Metal Co Ltd
Priority date: 1983-11-11
Filing date: 1984-11-09
Publication date: 1987-01-13
Also published as: GB2151641A; GB8428144D0; FR2554824B1; DE3441275A1; FR2554824A1; DE3441275C2; GB2151641B

Abstract

ABSTRACT
A hydrophilic film-forming composition which comprises a resin paint comprising a resin binder component and a paint vehicle with a solid ion exchange resin powder dispersed in the vehicle. A film produced therefrom has durable hydrophilic properties, and when combined with a suitable undercoat corrosion resistance is also improved.

Description

~2~669S

HYDROPHILIC-FILM-FORMING PREPARATIONS

BACKGROUND OF THE INVENTION

Field of the Invention:
This invention relates to hydrophilic-film-forming preparations which form hydrophilic films on surfaces of 5 materials such as metal, glass, plastics, etc.; to arti-cles having such hydrophilic films; and to a method of forming a hydrophilic film especially having corrosion resistance.
The term "article" as herein used means that made Of an appropriate industrial material such as metal, glass, plastics etc. in an appropriate shape, for example, a sec-tion such as a short-length plate material, a continuous-length plate material (e.g. a rolled product such as foil, sheet, plate), a circular material such as rod, bar, tubu-lS lar product, a press blank material, an extruded sectionetc. or workpieces obtained by processing the above into desired final shapes, which have been provided with a film, and in the case of a section, said shape also in-cludes that adaptable for plastic working processes such as forging, deep-forming, bending, punching, etc.

'~

, 12~61695 Descri tion of the Prior Art-p Hydrophilic-film-forming preparations are used for imparting hydrophilic films on material surfaces so as to prevent the formation o condensed water droplets on the material surfaces and also tor antistatic and defogging purposes.
For example, in heat exchangers equipped with plate or with corrugated fins, with the progress in the tendency to higher performance and to compactness, the inter-fin distance has been made smaller for improving heat transfer capacity. Heat exchange with the atmosphere is made via the fin surface and atmospheric moisture condenses on the fin surface, but if the inter-fin distance has been made smaller to e.g. 3 - 4 mm or less, the condensed water forms a bridge between the fins and hence increases the air-flow resistance, thus resulting in noise generation and a reduction in energy consumption efficiency, and therefore, it has been the practice to prevent the bridge formation by imparting hydrophilic properties to the fin surface. For imparting such hydrophilic properties, an appropriate means is employed according to the metal material used, and, for example, it is known to apply resin paints containing a silica powder or a surface active agent as an agent for imparting hydrophilic pro-perties. However, various problems were encountered;for example, the silica powder came off on press molding resulting in reduced uniformity of the film, and in order lZl~i695 to avoid this, if the silica powder was added in a large amount, it in turn reduced the thickness of the inorganic film and reduced the corrosion resistance of the film.
Whereas, if the hexavalent chrominum ion concentration was increased in order to offset this effect of silica, then the hexavalent ions dissolved out from the formed film and caused die abrasion when die molding was con-ducted after film formation, or the surface active agent gradually dissolved out with time to decrease the hy-drophilic properties, and in some use environments the increase in hydrophilic properties caused a decrease in the corrosion resistance of the metal material.

SUMMARY OF THE INVENTION
The present inventors have discovered that since ion exchange resins are inherently insoluble in water, have hydrophilic exchange groups and a strong capacity to absorb water from the atmosphere, by dispersing an ion exchange resin powder in a resin paint, an excellent hydrophilic-film-forming preparation may be obtained.
Furthermore, by providing an appropriate undercoat treatment, corrosion resistance is also improved.
Accordingly, it is a main object of this invention to provide film forming preparations having excellent hydrophilic properties.
Another object of this invention is to provide articles having a hydrophilic film on at least one sur-face thereof.

lZ1669S
It is yet another object of this invention to provide a method of forming a hydrophilic film on at least one surface of a material.
According to the invention there is provided a hydrophilic-film-forming preparation which comprises a liquid coating vehicle, a film-forming binder component in said vehicle and adapted to form a continuous film upon evaporation of said vehicle, and discrete solid particles of an ion exchange resin dispersed in said vehicle and insoluble therein.

DETAILED DESCRIPTION OF THE INVENTION
Examples of the material for the article include metal, glass, plastics and their composites. More spe-cifically, examples of the metal materials include iron, steel, aluminum, copper and other generally employed metals, and alloys thereof. Examples of the plastics include commercially available general-purpose thermo-plastic synthetic resins, thermosetting synthetic resins, reinforced plastics, etc. These materials may be pro-vided with an undercoat treatment, if desired, as decribedbelow in addition to surface cleaning such as degreasing etc. before forming a hydrophilic film.
The film-forming preparation which forms such a hydrophilic film is that having the components described below~
As the coating binder component, those conveniently FR011 ~ 561 571~ ' ~4 ~ 7 1~1 al ~` ~LZ:16695 ~9-7 used in resin paints may suitably be selected from among thermoplastic synthetic resins and ~hermosettins synthetic resins, but taking into considerat on the use conditions of the product to which the hydrophilic film is to be applied, the stability of the ion exchanse resin, etc., a resin having a softening temperature of 80~C or higher is preferred in the case of a thermoplastic resin. In the case of a thermosettin~ resin, if one ha~ing a setting temperature of higher than 150~C is used, the stoving time or the film is preferably 10 minutes or longer, whereas if a resin having a setting temperature of lower than 15CC. is used, the stoving heating time is preferably up to 1 minute.
As the resin in the coating binder component satisfying the above conditions, alkyd resins, acrylic resins, polyvinyl alcohol resins, vinyl acetate resins, epoxy resins, phenolic resins, polyester resins, silicone resins, fluorocarbon resins, urethane resins etc. may be used but these examples are merely illustrative and not limitative.
Further, the present film-forming preparation may contain, as a coating auxiliary element in order to obtain flowability on coating~ either water, in the case of a water-based paint, or a hydrocarbon, an alcohol, an ester, a ketone, an ether or ~he like in the case of an or~anic solvent~based paint depending on the characteristics of the resin used, as with the case of conventional paints.
~he amo~nt of the solven~ added ~ay be freely selected :12~66'95 in an appropriate range in order to obtain flowability according to the coating means as with the case of con-ventional paints, and also may be selected in an appro-priate range depending on the desired hydrophilic level.
As the ion exchange resin, in general, those ob-tained by attaching a hydrophilic atomic group, such as a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, a phosphinic acid group, a quaternary ammonium group or a primary or secondary amine group to a conden-sation type resin such as a phenolsulfonic acid type, an ethyleneimine - epichlorohydrin type, an epoxy resin etc., or to an addition polymeric resin obtained by copolymer-izing styrene or methacrylic acid with divinylbenzene as a crosslinking agent, are frequently used as cation exchange resins and anion exchange resins. Further, amphoteric ion exchange resins obtained by polymerizing acrylic acid to strongly basic anion exchange resins, fluorocarbon resins into which hydrophilic atomic groups have been introduced, etc. are commercially available and are also usable. From a viewpoint of providing hydrophilic properties, ion ex-change resins having an exchange capacity per gram of the dry ion exchange resin of 0.5 (meq./g-Dry R) or more, pre-ferably 1.0 (meq./g-Dry R) or more are employed in this invention. Those having less than 0.5 cannot provide the required wettability.
Furthermore, even that based on a phenolic resin may also be applied as an ion exchange resin if it is insoluble ' .'.~

i695 and possesses sur~ace active agent-like characteristics.
Of these ion exchange resins, cation exchange resins (also including alkali metal substituted salt types) are suitably employed in the respect that they are rich in hydrophilic properties and inter alia a sulfonic acid type strongly acidic cation exchange resin is most suitable.
Further, depending on the desired hydrophilic level, it is also possible to use a mixed system of two or more compo-nents obtained by mixing a strongly acidic cation exchange resin and a weakly acidic cation exchange resin, a highly basic ion exchange resin and a weakly basic ion exchange resin, or a cation exchange resin, and also possible to use a scrap ion exchange resin with or without a virgin speck.
Commercially available ion exchange resins are usu-ally particles of 10 - 50 mesh and therefore used after grinding according to the desired film thickness. In general, a film thickness of about 0.5 - 50 ~m is prac-tical. If it is less than 0.5 ~m, a film having desired characteristics cannot be stably obtained, whereas if it exceeds 50 ~m, improvement in the characteristics level according to the film thickness is not manifested but merely results in an increase in cost. Therefore, con-sidering film thickness, uniformity, etcO, it is general to grind to an average particle diameter of 1 m or less, for example, to effect grinding treatment by a vibrating ball mill etc. before use. For example, in the case of fins for heat exchangers, an average particle diameter lZ~669~5 of 0.5 - 1 ~m is preferred. Further, if that ground for an analytical grade for special purposes or for an ultrapure grade is available, it is needless to say that it may be used as such. Furthermore, it is also possible to apply a means for adjusting to a desired final particle diameter by auxiliarily utilizing a step of kneading with a resin paint.
While the amount of the ion exchange resin added relative to the coating binder component in the present film-forming preparation can be appropriately selected depending on the exchange capacity of the particular ion exchange resin used and the hydrophilic level desired for the formed film, it is necessary that the proportion of the ion exchange resin to the total weight of the coating binder and ion exchange resin powder be 0.1 or more on the dry weight basis (hereinafter, the aforesaid proportion is referred to as the "exchange resin ratio"). If the exchange resin ratio is less than 0.1, it is difficult to stably obtain the desired hydrophilic level. The exchange resin ratio is suitably in the range of 0.3 - 0.7. If it exceeds 0.7, the adhesion to the substrate is poor.
~ or example, where the present fil~-forming preparation is especially used for antistatic purposes requiring only hydrophilic properties, the exchange resin ratio is preferably 0.5 or more, but where both hydrophilic properties and die moldability are parti cularly required, it is preferred that the exchange resin ratio be 0.3 or more. Further, where lZ~695 applied to defogging of plastic materials, the exchange resin ratio can be as low as about 0.2 The solvent or vehicle for the coating auxiliary element may be added to the present film-forming pre-paration in a mode where it is added to a mixed stock solution of the coating binder component and the ion exchange resin in use, in a mode where these three mem bers are integrally added and mixed at the start, etc.
Further~ it is also possible to add to the present film-forming preparation various additives which impart various properties to the paint. More specifically, a dispersant, a mildewproofing agent, an anti-skinning agent, a slip agent, an antifoaming agent etc. may be added in amounts of about 1 - 2% by weight respectively if desired. Furthermore, as an agent for improving the initial hydrophilic properties, a surface active agent such as ~-olefinsulfonates etc. may be added in an amount of 0.5 - 10% by weight.
The use embodiments of the present film-forming preparation are now described. Any conventional coat-ing means in the paint art may be used, for example, roll coating, spraying, dipping, brushing, spin coating etc., and the coating weight in this case is suitably 1 - 3 g/m2 (dry basis). If the paint is an air dry-ing type, then it is coated and thereafter air dried as such to fix the film, or if the paint is a thermosetting type, stoving is conducted under proper heating condi-tions which do not adversely affect the characteristics _ g _ ..~,~,.

FRO11 8~ 561 5718 ~216695 '84. 11.117 1~i08 o~ the ion exchange resin. In the next place, as pre-treatment for the film-forming treatment, it is also an effective mea~s to apply undercoat treatment described hereinbelow for the p~rpose of improving the corrosion resistance of the material surface and the ~ixing of the film.
As the undercoat treatment, a method of forming an oxidized film or a method of forming an anti-corrosive metal film using aluminum, zinc, copper, chrominum etc., and the ~ike, may be used or these two methods may be used in com-bination.
As the method of forming an oxidized film, any of conventional methods, e.g. a chemically oxidized film method, an anodized film method etc. can be used, but the chemically oxidized film method is pre~erred because a film of a relati-vely thin thickness having excellent corrosion reistance can be continuously and inexpensively obtained.
Examples of the chemically oxidized ~ilm method include, according to the bath component, the so-called alkali chromate methods such as M3V method, ~W method, Pylumin method and Alrock method and the so-called acidic chromate methods such as Bonderite method, and Alodine method, as well as Boehmite treating method, a phosphate salt method etc. In ~eneral, there is employed a chromate ~ilm treatin~
method which comprises using chromic acid luoride as a main bath component and treat~ing at a bath tempe~ature of 20 - 40C

FROrl ~ 561 5718 12~L6695 a4 ll e7 131 1~

for 5 seconds to 5 minutes, a chromium phosphate film treatirg method which comprises usin3 ch~omic acid, hydrofluoric acid and phosphoric acid as main bath components and treat in~ at 26 - 60C for 30 seconds to 7 minutes, a phosphate salt film method which comprises using a phosphate salt such as zinc phospate, mAnganese phospate etc. as a main bath component and treating at a bath temperature of 60 - 100qC for about 5 minutes, or a 30ehmite film method which comprises treating with hot water-saturated steam, triethanolamine etc., and the like.
These methods may be effected by dipping, spraying, roll coatin~, steam gun method etc. By these methods, a chemically oxldized film of O.OQ5 Ym or more in thickness is formed, and with less than 0.005~m, the characteristics as the anti-corrosive underocat are insufficient. ~or example, in the case of fins for heat exchangers, about 0.01 - 0.5 ~m is preferred, and where there is no need for molding after the film ~ormation, or where the heat conductivity of the film is not important, a film thickness of 5 ~m or more can also be used.
Examples of the method of forming ~n anti-corrosive metal film include electroplating, deposition, flame spraying, cladding etc. using a metal such as aluminum, zinc, copper, chromium etc. and an appropriate method is selected therefrom according to the nature of the metal material and the use.
In other words, for example, in the case of zinc FR~M a3 561 5718 12~669S ~a4. 11.07 1~1 12 coating, a zinc film may be formed by a method which comprises electroplating in a bath con~aini~g ~SO - 240 g/l of zinc oxide, 500 - 550 g/l of sodium hydroxide and 5 - 10 ~/l o~
sodium cyanide as main components, an acidic zinc electro-platin~ bath method using 3inc sulfate, æinc chloride andzinc borofluoride, a zincate electroplating bath method usin~ zin^ oxide and sodium hydroxide as main components, a neutral zinc electroplating bath method in which the bath contains a chelating agent such as an oxy acid in addition to zinc chloride, a pyrophosphoric acid bath method etc., or a molten zinc plating method which comprises flux pre-treating with ammonium chloride and ammonium 2inc chloride and subsequently dippin3 in a molten metallic zinc bath, zinc flame spra~ing, cladding, or the like. As the method of coating alu~inum, there may be used molten aluminum plating which comprises dipping in a flux bath comprising a chloride system o~ potassium chloride and sodium chloride or a fluoride system of cryolite and aluminum fluoride and subsequently dipping in a molten aluminum bath, plasma flame spraying, vacuum deposition, cladding etc.
By these methods, an anti-corrosive metal film of 3 ~m or more in ~ilm thickness is formed, and if the thickness is less than 3~-~, the characteristics as the anti-corrosive undercoat are insuf icient. ~he film thickness varies depending on the use purpose, and, for example, in the case of fins for heat exchangers, about _ 12 -FRO~ 13~ ~61 5718 ' 84. 1 1 . a7 1~
~: 1216695 29-15 5 _ 10 ~m is preferred, but where there is no need for molding after the film formation or where the heat conduct1vity of the film is not importar.t, an appropriate thickness of ~ore than 10 ~m may be used.
Of the~e methods, as the undercoat treatlng method of improving the corrosion resistance, the chromate treatin~
method is most pre~erred in practice and this can exert the best effects including economy.
The hydrophilic ilm according to this invention has been described above, ahd the film formed with the present preparation has such features as extremely low deterioration with time in use and very small die abrasion when a material to be treated is die molded after vhe film formation. There-~ore, it is not only suitable as a hydrophilic-film-forming preparation for fin members ~or heat exchangers equipped with high density fiGs but it also can form a film rich in the power to retain hydrophilic properties which is not achievable with the conventional preparations and thus may be used for e.g. antistatic defogging purposes etc., and, in addition, by providing desired undercoat treatment, excellent corrosion resistance is manifested.
This invention is more particularly described by the followin~ examples.

..
A co~merically available sulfonic acid type poly-styrene-ba6ed cation exchange resln: 4.5 (meg/g-DRY R) :lZ~669S
(Amberlite* IR-120 produced by Rohm & Haas Co.) was ground in a vibrating ball mill for about 30 minutes and dried by an infrared lamp to obtain a fine powder of an average particle diameter of 15 ~m and a water content of 12%.
Thereafter, 200 g of this fine powder, 650 g of an epoxy ester-based water soluble paint (Watersol* S-352 produced by Dainippon Ink and Chemical, Inc., solids content 46%), 100 g of butyl Cellosolve* and 400 g of water were added to a pot mill and kneaded for about 6 hours to achieve uniform dispersion. As a result, the secondary particle diameter of the ion exchange resin became 0.5 - 1 ~m.
The resultant film-forming preparation was coated using a bar coater (#12) on a previously cleaned aluminum panel as a material and dried at 230C for 30 seconds to fix.
COMPARATIVE EXAMPLES
In a case where the epoxy ester-based paint used in Example 1 was directed coated tComparative Example 1) and a case where a commercially available thermosetting acrylic resin paint containing a wet type surface active agent (solids content 18%) was coated (Comparative Exam-ple 2), treatment was conducted using coating and drying conditions similar to those in Example 1. The products of these examples and comparative examples were sub~ected to various tests. The results are shown in the following Table 1.
In the table, the initial wettability shows the wetted * Trade Mark c~

FRO~1 a3 561 5718 ' 34 . I I . ~7 13 1 ~ 7 ` 1;~1669S

conditions of a 6ample 30 seeonds after picking up said sample dipped in deioni.zed water, and is expressed relative to the case where the entire surface has been wetted taken as 100~.
Table 1 _ _. . _...... _ .. ~
Water Wettabili~y Die Brine . _ Molda- Spraying Initial Wetting bility Test Wettabi- Test (a~ter lOOhrs) . . . . _ _ _ _ _ 100~ even ! Corrosion Example 1 100~ after 1000 Good within 5%
_ Comparatlve 0 0 Good 1, -do-_ . t --~- --------- ... .
Example 2 100% 30%hraf5ter Good -do-. . ._. ~,,,~ . __. . . _.. _ _ ._ _ . _ .. _ . _. _ .. . . . . . . emarks Wetting Test: The sample was left in an atmosphere of a temperature of 50C and a humidity of 100~.
Die Moldability: Evaluated by the die abraded condltions.
From these results, it can be seen that where the resin paint of Comparative Example 2 is used, although the die mold-ability after the film formation is good, the deterioration of the hydrophilic properties (in this case, expressed by the water wettabillty) is less with the case of this lnvention and better results are obtained by this invention.

~2~6695 EXAMPI,E 2 8 g of a 5~ solution of cobalt naphthenate was added as a drier to the composition of ~xample 1, and a similar kneading operation was conducted. The resultant paint was coated on a previously degreased aluminum fin plate material for heat exchangers, forcedly dried and left at room temperature for 3 days to fix the film.
Thereafter, a test similar to that in Example 1 was conducted to obtain almost similar results, and, in parti-cular, it was found that there was remarkable enhancement in durability against xylene, thus indicating improved corrosion resistance. This is believed due to the action of cobalt naphthenate as a catalyst.
EXAMP~E 3 A fine powdered sulfonic acid type polystyrene-based cation exchange resin obtained by the process described in Example 1: 4.5 (meq./g-DRY R) (Amberlite* IR-120) was mixed with an air drying acrylic resin paint ~Acrydic*
A-165 produced by Dainippon Ink and Chemical, Inc.; sol-ids content 45%) at an exchange resin ratio of 0.70 also together with 0.5% based on the resin paint total weight of a wetting dispersant (BM 1000* produced by Bayerische Motoren Werke AG, West Germany) for improving the dispers-ibility of the ion exchange resin, and thereafter kneading was similarly conducted in a pot mill for 5 hours.
The resultant film-forming composition was coated on a * Trade Mark ~2~6695 transparent plastic plate of l.Omm in thickness to a dry film thickness of 0.5 ~m and left at room temperature to dry and fix.
The coated surface o~tained was subjected to an exposure test under conditions of an atmosphere of a temperature of 40C and a relative humidity of 90 + 5 percent and an outer temperature of 27C. As a result, the plate having a film formed according to this in-vention kept transparent and did not show cloudiness, whereas a naked plastic plate without coating showed cloudiness on the entire surface.

250 g of a dried fine powder (average particle diameter 1.0~ m, water content 5~) of a weakly acidic cation exchange resin; 10 (meq./g-DRY R) (Amberlite*
I~C-50 produced by Rohm & Haas Co.)., 700 g of a modified alkyd resin paint (P- 86-50* produced by Dainippon Ink and Chemical, Inc.), 300 cc of xylene, 30 g of a dispers-ant (BM1000* produced by Bayerische Motoren Werke AG, West Germany) and 7 g of a leveling agent (BM1800A* produced by Bayersiche Motoren Werke AG, West Germany) were added to and mixed in a high speed mixer for 30 minutes. The solids content of the alkyd resin paint was 50~, and the exchange resin ratio of the resultant film-forming pre-paration was 0.38.

* Trade Mark ~2~1695 This film-forming preparation was coated by brushing on a zinc plated steel plate, and heated at 200C to form a film.
The wettability of the film was measured under con-ditions similar to those in Example l to obtain a wettingtest result of 97% after 48 hours, which indicated that the deterioration of the hydrophilic properties was ex-tremely low.
EXAMPL~ 5 A hydrophilic-film-forming preparation produced simi-larly as in Example l (except that ~he average particle diameter of the ion exchange resin ground in the vibrating ball mill was 1.0 ~m and the water content after drying by an infrared lamp was 5%) was continuously coated by a roll coater on a previously degreased rolled fin material for aluminum heat exchangers as a material, and dried in a hot air drylng oven at 230C for 30 seconds to fix.
A test sample was prepared from the resultant fin material, this sample was dipped in deionized water, picked up and the water wettability 30 seconds later was measured to give 100%, and when a wetting test (conducted in an atmosphere of a temperature of 50C and a humidity of 100%) was carried out, the water wettability was found 100% even after lO00 hours. Further, the brine spraying test result showed a corrosion rate after lO0 hours of within 5%.
Thereafter, the film-formed fin material as an article ~16695 was punched into fin members of a desired shape by press molding and the fin member surfaces were provided with louver processing.
In the press molding, neither abrasion of the molding die nor damage to the film was observed as was observed with silica-containing hydrophilic films, and thus good working had been effected. Further, when the resultant fin members were used by assembling into an automobile condenser, the intended continuous operation was possible even when there was a change in humidity in the atmosphere.

A coiled aluminum fin material (made of AA 310-5 alloy, plate thickness 0.12 mm) degreased with a weakly alkaline cleaner (trade name~ FC 315 produced by Nihon Parkerizing Co., Ltd.) was coated with a phosphoric acid -chromate type treating agent having a concentration of 1.3~ by weight (trade name: Alodine 401-45 produced by Nippon Paint Co., Ltd.) by spraying by heating at 35C
to form an undercoat of about 70 A on the surface.
Thereafter, a sulfonic acid type ion exchange resin (trade name: R-120B produced by Japan Organo Co., Ltd.) of an average particle diameter of 0.5 ~ 1~ m was added to a catalytically curing epoxy ester-based water paint (trade name: Watersol S346 produced by ~ainippon Ink and Chemical Co.) so as to give a dry solids content of 40% by weight, and thoroughly mixed to prepare a hydrophilic film-forming composition, which was then coated on the above ,, 12~l.6695 undercoat to give a coating weight of 1.5 9/m2 ~dry basis) and heated at 230C in a hot air drying oven for 30 seconds to effect stoving heating treatment.
The coiled material obtained by the above film-forming treatment was subjectec3 to punching and wiping to prepare cross members, which were evaluated by tests for hydrophilic properties and corrosion resistance.
More specifically, the long term stability of the hydrophilic properties was evaluated by the percentage area wetted when left in an atmosphere of a relative humidity of 95% and a temperature of ~0c for soo hours, and this was 100%, thus confirming good hydro-philic properties.
On the other hand, the corrosion resistance was eval-uated by a 500 hour brine spraying test according to JIS Z 2371 (1955), and it was found that corrosion had been generated neither in the unprocessed part nor in the wiped part, thus confirming also excellent corrosion resistance, and therefore, it was confirmed that by this invention, a film excellent in both hydrophilic proper-ties and corrosion resistance may be obtained and that machinability after the film formation i5 also excellent.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that variations and modifications can be made therein without departing from the spirit or scope of the invention thereof.

~.

~2~6695 For example, it is possible that a hydrophilic film-forming composition is formed immediately on an article surface by means of mixing components which comprises a step of forming an resin paint film on the article surface and a step of spraying an ion exchange resin powder on said resin paint film.

:.. ,~ r, b,

Claims

Claims:

1. A hydrophilic-film-forming preparation which comprises a liquid coating vehicle, a film-forming binder component in said vehicle and adapted to form a continuous film upon evaporation of said vehicle, and discrete solid particles of an ion exchange resin dispersed in said vehicle and insoluble therein.

2. The film-forming preparation according to Claim 1 wherein the proportion of the ion exchange resin in the total weight of said binder component and ion exchange resin powder particles on the dry weight basis is 0.1:1 or more.

3. The film-forming preparation according to Claim 1 wherein said binder component is a thermoplastic synthe-tic resin having a softening point of 80°C or higher.

4. The film-forming preparation according to Claim 1 wherein said binder component is at least one resin selected from an alkyd resin, an acrylic resin, a poly-vinyl alcohol resin, a vinyl acetate resin, an epoxy resin, a phenolic resin, a polyester resin, a silicone resin, a fluorocarbon resin and a urethane resin.

5. The film-forming preparation according to Claim 1 wherein said coating vehicle is water or one member selected from the group consisting of a hydrocarbon, an alcohol, an ester, a ketone and an ether.

6 . The film-forming preparation according to Claim 1 wherein said ion exchange resin powder has a total exchange capacity is 0.5 (meq./g-DRY R) or more.

7. The film-forming preparation according to Claim 1 wherein said ion exchange resin powder has a total exchange capacity is 1.0 (meq./g-DRY R) or more.

8. The film-forming preparation according to Claim 1 wherein said ion exchange resin powder is ground to an average particle diameter of 1 µm or less.

9. The film-forming preparation according to Claim 1 or 2 wherein said preparation further contains 1 - 2%
by weight of at least one member selected from the group consisting of a dispersant, a mildewproofing agent, an anti-skinning agent, a slip agent and a defoaming agent.

10. The film-forming preparation according to Claim 1 or 2 wherein said preparation further contains 0.5 - 10% by weight of a surface active agent.

11. An article having a film-formed from a hydrophilic film-forming preparation according to Claim 1 on at least one surface.

12. An article having a film formed from a hydrophilic-film-forming preparation according to Claim 1 on at least one surface and superposed on an undercoat.

13. The article according to Claim 11 or 12 wherein the thickness of the film formed with said hydrophilic-film-forming preparation is 0.5 - 50 µm.

14. A method of forming a hydrophilic film on a substrate which comprises the step of applying to said substrate a film formed of the hydrophilic-film-forming preparation according to Claim 1.

15. The method according to Claim 14, including the step of applying to said substrate a preliminary undercoating, comprising an oxidized film or an anti-corrosive metal film.

16. The method according to Claim 15 wherein said oxidized film is formed by a chemically oxidized film method or an anodized film method.

17. The method according to Claim 15 wherein said anti-corrosive metal film is formed by electroplating, deposition, flame spraying or cladding.

18. An article having a hydrophilic film on a surface thereof, said film having an ion exchange resin powder dispersed therein.

19. The article according to Claim 18 which has been provided with undercoat on such surface thereof.

20. The article according to Claim 18 or 19 wherein the thickness of said film is in the range of 0.5 - 50 m.

21. The article according to Claim 18 wherein said material is at least one material selected from the group consisting of a metal, a glass and a plastics.

22. The article according to Claim 21 wherein said metal material is iron, steel, aluminum or copper.

23. The article according to Claim 21 wherein said plas-tics is a thermoplastic synthetic resin, a thermosetting synthetic resin or a reinforced plastics.

24. The article according to Claim 18 or 19 wherein said hydrophilic film is formed on at least one surface of the material by roll coating, spraying, dipping, brushing or spin coating.

25. A method of forming a hydrophilic film on a substrate which comprises the step of forming a hydrophilic film having an ion exchange resin powder dispersed therein on said substrate.

26. The method according to Claim 25 including the step of forming on said substrate a preliminary undercoat comprising an oxidized film or an anti-corrosive metal film.

27. The method according to Claim 25 wherein said oxidized film is formed by a chemically oxidized film method or an anodized film method.

28. The method according to Claim 27 wherein said chemi-cally oxidized film method is an alkali chromate method, an oxidized chromate method, Boehmite method or a phos-phate salt method.

29. The method according to Claim 27 wherein said chemi-cally oxidized film is formed by dipping, spraying, roll coating or a steam gun method.

30. The method according to Claim 26 wherein the thickness of said chemically oxidized film is 0.005 µm or more.

31. The method according to Claim 26 wherein said anti-corrosive metal film is formed by electroplating, deposition, flame spraying or cladding.

32. The method according to Claim 26 wherein the thickness of said anti-corrosive metal film is 3 µm or more.

33. The method according to Claim 25 wherein said hydro-philic film is formed by roll coating, spraying, dipping, brushing or spin coating.

34. The method according to Claim 25 wherein the thickness of said hydrophilic film is 0.5 - 5 µm.