JPH03265700A - Water-and oil-repellent for use in leather - Google Patents

Abstract

PURPOSE:To provide a water-and oil-repellent which can give good water and oil repellency and durability to natural and synthetic leather by using a copolymer of a specific fluorine-containing urethane compound with other copolymerizable compounds as the active principle. CONSTITUTION:A water-and oil-repellent for use in leather has an active principle comprising a copolymer of a fluorine-containing urethane compound (A) containing (meth)acryloyl or allyl and polyfluoroalkyl groups with a copolymerizable compound (B) other than component (A). Component (A) is obtained by reacting an at least trifunctional isocyanate compound, a hydroxyl compound containing a (meth)acryloyl or allyl group and a hydroxyl compound containing a polyfluoroalkyl group. Component (B) should preferable contain a (meth)acryloyl or allyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a water and oil repellent for leather that is particularly effective in imparting water and oil repellency and durability to leather.

[Prior Art] In recent years, water- and oil-repellent finishing for clothing has been actively carried out, and various compositions have been provided. There is no composition. Conventionally, polyfluoroalkyl group-containing chromium complexes (USP 293
Specification No. 4450, JP-A-35-17013, L
ISP3471518) and a copolymer of polyfluoroalkyl group-containing acrylate and vinylidene chloride (U
SP3524760) and the like are known as fluorine-based water and oil repellents for leather, but in any case there has been no composition that satisfies both initial performance and durability.

In particular, the latter has many drawbacks, such as being difficult to clean, being susceptible to abrasion, and changing the appearance of the material. Therefore, in order to improve these drawbacks, a composition containing a polyfluoroalkyl group and a urethane chain in one molecule (
US Pat. No. 3,468,924) and a blend composition of this urethane composition and a polyfluoroalkyl group-containing (meth)acrylate copolymer was developed. These compositions have excellent properties such as high water and oil repellency, high friction durability, and a comfortable touch, but they do not form a film on leather because the urethane compound itself does not have film-forming properties. Therefore, it had the disadvantage that it had no durability at all against dry cleaning and also had unsatisfactory durability against stains.

On the other hand, copolymers of urethane (meth)acrylate containing a barfluoroalkyl group and other vinyl monomers have been developed by focusing on the non-adhesive properties of their surfaces. Examples include release coating agents. Since these are insolubilized during polymerization by di(meth)acrylate produced as a by-product during urethane (meth)acrylate synthesis, the products obtained by ordinary polymerization are not worth using. For this reason, special restrictions must be met, such as coating the monomer as it is and polymerizing it later, or using a solution polymerized under very limited conditions. Therefore, it cannot be used at all as a water and oil repellent for leather. In addition, this compound uses a bifunctional isocyanate because it is intended to be used as a release coating agent, and on the other hand, when used as a water and oil repellent for leather. Therefore, urethane compounds using bifunctional incyanates cannot exhibit satisfactory performance on leather, such as water and oil repellency and friction durability. It has been impossible to achieve the performance required of oil repellents.

[Problems to be Solved by the Invention] An object of the present invention is to overcome the above-mentioned drawbacks of the prior art. In other words, polyfluoroalkyl group-containing (meth)acrylate copolymers have disadvantages such as fragility to abrasion and adhesion to materials, and compositions containing polyfluoroalkyl groups and urethane chains in one molecule have disadvantages such as dryness. This is an attempt to simultaneously eliminate both of the disadvantages of lack of durability against cleaning and unsatisfactory durability against dirt.

[Means for Solving the Problems] As a result of intensive research in view of the problems of the prior art, the present inventor has found that We have discovered that a copolymerized latex of a fluorine-containing urethane compound containing a polyfluoroalkyl group and a copolymerizable compound other than the fluorine-containing urethane compound can impart outstanding water and oil repellency and dry cleaning durability to leather products. This led to the invention.

That is, the present invention provides compounds obtained by reacting a polyfunctional incyanate compound that is at least trifunctional, a hydroxyl compound containing a (meth)acroyl group or an allyl group, and a hydroxyl compound containing a polyfluoroalkyl group (
Provided is a water and oil repellent agent for leather, the active ingredient of which is a copolymer of a fluorine-containing urethane compound containing a meta)acroyl group or an allyl group and a polyfluoroalkyl group and a copolymerizable compound other than the fluorine-containing urethane compound. It is something to do.

In the present invention, the fluorine-containing urethane compound containing a (meth)acroyl group or an allyl group and a polyfluoroalkyl group includes at least trifunctional polyfunctional isocyanate compounds, hydroxyl compounds containing a (meth)acroyl group or an allyl group, and It is obtained by reacting a hydroxyl compound containing a polyfluoroalkyl group. In order to suppress the formation of a urethane compound that does not contain a polyfluoroalkyl group, first, a hydroxyl compound containing a polyfluoroalkyl group is reacted with a polyfunctional isocyanate compound, and then the reaction product is reacted with a (meth)acroyl group or an allyl group. Preference is given to reacting hydroxyl compounds containing groups.

The reaction molar ratio of the polyfunctional incyanate compound, the hydroxyl compound containing a (meth)acroyl group or allyl group, and the hydroxyl compound containing a polyfluoroalkyl group is 3 moles of the isocyanate group to 3 moles of the (meth)acroyl group or allyl group. A suitable molar ratio of the hydroxyl compound containing the hydroxyl compound and the hydroxyl compound containing the polyfluoroalkyl group is 1:2 to 2.8:0.2.

As the polyfunctional incyanate compound in the present invention,
The following bifunctional incyaneto compounds may be used, but
In order to exhibit performance as a water- and oil-repellent agent for leather, it is particularly preferred that it be at least trifunctional. Examples of difunctional incyaneto compounds include aromatic incyanates such as 2.4-tolylene diisocyanate, 4.4'-diphenylmethane diisocyanate, tolidine diisocyanate, dianisidine diisocyanate, and 2-methyl-cyclohexane-1,4- Diisocyanate, inphorone diisocyanate, hydrogenated MDI (OCN @CH,
Examples include compounds such as alicyclic diisocyanates such as <E> NGO) and aliphatic incyanates such as hexamethylene diisocyanate and decamethylene diisocyanate. If these are represented by the formula 0CN-Y-NCO, then when two 0CN-Y-NCOs are reacted in the presence of water, a dimer such as 0CN-Y-NHCONH-Y-NCO is produced, The term "bifunctional incyaneto compound" also means such a dimer.

Polyfunctional isocyanates such as trifunctional, tetrafunctional, and pentafunctional are preferable to difunctional in terms of water and oil repellency and durability, and two or more types of polyfunctional isocyanate compounds with different functional numbers are used in combination. Specific examples of trifunctional isocyanate compounds that may be used include the following compounds, but as mentioned above, -mer 0CN-Y-NCO and dimer 0CN
0 obtained by reaction of -Y-NHCONH-Y-NCO
CN-Y-N-CONH-Y-NGO\C0NH-Y-NCOl It also means a compound having three -NGO groups, such as a tetramer in which dimers have reacted with each other.

Examples of such trifunctional incyaneto compounds are: vinegar etc., but is not particularly limited by the example.

Considering processing into leather, aliphatic incyanates are more suitable for the purpose of avoiding yellowing during use and improving adhesion to leather. (meta)
As a hydroxyl compound containing an acroyl group or an allyl group, CH2=CR4C00CH,CH,0HCH*=CR-
COOCHtCHCH-H CH,=CR4C00CH,CH,CH,0)ICH2
=CR, C00 (C, H40), H (P is 1 to 12) C
H*=CR4C,00(C,H@0)PH(P is 1 to 1
2) CH! =CHCHffiO(C,H,0),H(P
1 to 12) (herein, R4 is Hl or CHs), and these can be used in combination.

Preferred examples of the hydroxyl compound containing a polyfluoroalkyl group include RfCH, CH, OH Jy ■ RfCONCH, CH20H con OH 1 RfSO, NCH, CH20CH2CHCH2C1, and two or more of these,
Alternatively, it is also possible to use two or more kinds of compounds having different numbers of carbon atoms in polyfluoroalkyl groups.

The above-mentioned Rf is a linear or branched polyfluoroalkyl group having 1 to 20 carbon atoms, preferably 4 to 16 carbon atoms, and is usually selected to have a polyfluoroalkyl group at the terminal end. Those containing a hydrogen atom or a chlorine atom at the end, or a group containing oxypolyfluoroalkylene can also be used. A preferred embodiment of Rf is CnF
A polyfluoroalkyl group represented by 2□, + (where n is an integer of 4 to 16), where n is 6 to 12
Particularly preferred are those.

Compounds that can be copolymerized with the fluorine-containing urethane compound synthesized from these raw materials include the following copolymerizable compounds other than the fluorine-containing urethane compound: CHz"CR4C00R-CHs:CR-COOCH-
CH2RfCH2=CR4COO(CH,CHlO)P
H (P is 1-12) CH! =CR, C00CH, CH-
CH.

Methacrylic acid and acrylic acid or their esters such as \1 (where R4 is Hl or CHl, R2 is Hl or C1IH2q□, and q is 1 to 23, preferably 1 to 6), CH, =CR, C0NHCH, OHCH,=CR4C0
NHC) 1.0c4H.

CH,=CHCl C)1. =CC1゜CH
,=CH0COCH,CH,=CHCH10HCHCO
OC, H, CHCOOC8HI? (Here, R4 is Hl or CH.). Furthermore, two or more of these copolymerizable compounds can also be used in combination.

In order to suppress the formation of a homopolymer of the fluorine-containing urethane compound itself, the copolymerizable compound other than the fluorine-containing urethane compound is preferably a non-fluorine copolymerizable compound containing a (meth)acroyl group or a vinyl group. Also,
Especially when considering use on leather, from the viewpoint of film-forming properties, suitable second components include isobutyl (meth)acrylate, styrene, vinyl chloride, and vinylidene chloride, which have high film-forming properties. can. Furthermore, considering adhesion and adhesion to leather, polarizable and adsorbable components such as glycidyl (meth)acrylate, N-methylol acrylamide, N-butoxymethyl acrylamide, and hydroxyethyl (meth)acrylate are recommended as third components. Addition of a monomer having as a functional group can be cited as an effective way to improve durability.

In order to obtain a copolymer of a fluorine-containing urethane compound and a copolymerizable compound other than the fluorine-containing urethane compound, various polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be employed. In addition, various polymerization initiation methods can be adopted, such as polymerization using an initiator, radiation polymerization, and photopolymerization, but suspension polymerization and solution polymerization result in gelation and insolubilization, so leather repellent It is difficult to use as a water and oil repellent. Therefore, the following suspension polymerization is preferred. That is, a method in which a fluorine-containing urethane compound and a copolymerizable compound other than the fluorine-containing urethane compound are dissolved in a water-insoluble organic solvent, and then emulsified and dispersed in water and polymerized. After polymerization, the solvent is distilled off. For example, a water-dispersible water- and oil-repellent agent for leather made of the copolymer of the present invention can be obtained. The water and oil repellent for leather in the present invention can be used in the form of an organic solution or an organic dispersion, but consideration must be given to its application to leather pre-treatment processes and the impact on the working environment during water and oil repellent treatment. Then, the surfactant as a dispersant for forming a water-dispersible type, which is particularly preferably a water-dispersible type, is nonionic,
Various types such as anionic, cationic, and amphoteric types can be used, and these may be used in combination as appropriate. in particular,
Nonions such as polyoxyethylene monooleyl ether, polyoxyethylene monoalkyl ether, polyoxyethylene mono(alkylphenyl) ether, polyoxyethylene monooleyl ester, polyoxyethylene monoalkyl carboxylic ester, sorbitan ester, sucrose ester, etc. cationic surfactants such as tertiary amine acetates and quaternary ammonium salts, anionic surfactants such as sodium alkyl sulfonates, alkyl carboxylic acids and their salts, and sodium alkoxypolyoxyethylene sulfonates. Amphoteric surfactants such as betaine type surfactants or phosphoric acid ester type surfactants such as choline and ethanolamine are preferred.

The presence of a water-insoluble solvent facilitates emulsification and improves copolymerizability with a urethane compound having a methacroyl group, an acroyl group, or an allyl group and also containing a perfluoroalkyl group. Suitable solvents for this purpose can be used without particular limitation as long as they dissolve both the above-mentioned urethane compound and the copolymerizable compound and are insoluble in water. Suitable examples include ketones such as methyl acetate, esters such as ethyl acetate, butyl acetate, and hydrocarbons such as benzene, toluene, xylene, hexane, and cyclohexane. The amount of these organic solvents added is usually selected from the range of 10 to 300 parts by weight, preferably 20 to 120 parts by weight, per 100 parts of the copolymer of the present invention.

When the water and oil repellent for leather of the present invention is made into a water dispersion type, the solid content concentration of the copolymer of the present invention is not particularly limited, but is usually adjusted to 5 to 60 wt%, preferably 5 to 50 wt%. , during processing, add water to 0.2 to 4
It is used diluted to about wt%. Such a water-soluble dispersion-type water and oil repellent for leather has advantages over organic solvent-based ones, such as a higher flash point of the stock solution and the ability to increase the solid content concentration. It has various advantages such as being able to minimize pollution of the working environment during processing.

As the initiator used for polymerization, it is preferable to use an oil-soluble initiator among azo initiators and peroxide initiators. For example, 1 cN is preferred. The polymerization temperature can be selected depending on the initiator, but 40°C to 80°C is usually suitable.

The fluorine content in the resulting copolymer of the present invention is 2 to 2.
The amount is preferably 50 wt%, preferably 8 to 30 wt%, and if it is too little or too much, the water and oil repellency after treating the leather will be unfavorable.

Leather products that can be treated with the water and oil repellent for leather of the present invention include:
Various examples can be given without particular limitation.For example,
Preferred applications include leather products such as bags and bags, leather products for clothing, and shoes. In addition, for leather gloves (particularly for golf, skiing, etc.), the provision of water and oil repellency and high durability can provide very excellent effects for the purpose of use.

The method for applying the antifouling agent of the present invention is not particularly limited, and various well-known or well-known methods can be employed. For example, by known coating methods such as dipping, spraying, and coating, It is possible to apply the material by attaching it to the surface of the object to be treated or by absorbing it and then drying it.

In addition, various processing agents and additives such as antistatic agents, insect repellents, flame retardants, dye stabilizers, and anti-wrinkle agents can also be used during construction.

[Function] In the present invention, the main component of the processing agent is a pendant polymer having a giant segment called a urethane component containing a polyfluoroalkyl group at the end of a polymer side chain. Among these, by using a comonomer with binding groups that are highly adsorbable to leather, such as side chain urethane bonds and urea bonds, and a functional group that is highly adsorbable to leather as the third component of copolymerization, it is possible to It exhibited adhesion and excellent water and oil repellency. In addition, by using a comonomer with high film-forming properties as the second component of the copolymerization, the film-forming properties of the polymer are dramatically improved, which, in combination with high adhesion to leather, is thought to give high dry cleaning durability. It will be done.

[Example] Synthesis Example 1 100 parts of hexamethylene diisocyanate trisbiulet and 374 parts of methyl isobutyl ketone were placed in a 1β3 Tulo flask equipped with a stirrer, and while stirring at 200 rpm, N8 gas was blown in to remove water. It was heated to 60°C, 0.1 part of dibutyltin dilaurate was added as a catalyst, and perfluoroalkylethyl alcohol: (CJzn, + CHIICH20H: n @ 9
) [Abbreviated as Rf der Ruhr] 195 parts were applied over 2 hours. Subsequently, polyoxyethylene mono(methacroyl)ester; (CH-:CR4C00(CHsCHxolnH: n
80 parts of "F8" were added dropwise over 30 minutes.The reaction was continued for 4 hours and the reaction was completed.

It was confirmed by IR that the incyanate peak had disappeared. It was confirmed by NMR that a urethane compound consisting only of Rf dealul and the incyanate was not detected.

Synthesis Examples 2 to 1O Synthesis Examples 2 to 10 were synthesized in the same manner as Synthesis Example 1. Results first
~2 Table shows.

Comparative Synthesis Example Synthesis was carried out in the same manner as in Synthesis Example 1 except that diisocyanate was used instead of polyisocyanate. The results are shown in Table 3.

Example 1 120 parts of the urethane compound of Synthesis Example 1 (solid content 60 parts, M
60 parts of IBK) and inbutyl methacrylate (iBMA
) to 160 parts of a mixture of 40 parts of polyoxyethylene nonylphenyl ether (Emulgen manufactured by Kao Corporation) as an emulsifier.
920) 1.8 parts, N,N-dimethylstearylamine acetate (Armine DM 180 acetate, manufactured by Lion Corporation)
After adding 7.2 parts and heating to 50℃ to dissolve, add 200℃ of warm water at 50℃ while stirring with a homomixer (manufactured by Tokushu Kika Co., Ltd.).
Added a section. Furthermore, 100 parts of this emulsion and 01 part of azoisobutyronitrile as a polymerization initiator were added to a polymerization ampoule which had been treated with a high-pressure homogenizer, and reacted in an autoclave at 60°C for 20 hours. The monomer reaction rate was approximately 100%. After the polymerization reaction, the baying agent MI BK was distilled off under reduced pressure to obtain a milky white stable latex. Observation using an N-son microscope confirmed that uniform spherical particles with a particle diameter of 0.3 parts m were formed. In order to confirm that there were no urethane compound homopolymers and iBMA homopolymers, the latex was dispersed in methanol and precipitated to recover the solid content, and solvent extraction was performed with benzene and methyl ethyl ketone, respectively. The extracts are O,
They were 1wt% and 0.2wt%.

Examples 2 to 4 A milky white stable latex was obtained in the same manner as in Example 1 except that the urethane compounds of Synthesis Examples 2 to 4 were used.

Example 5 120 parts of the urethane compound of Synthesis Example 1 and 35 parts of iBMA,
N-butoxymethylacrylamide; (CHlCHCO
ONHCH-QC4He) [abbreviated as N-B M]5
Add 5.5 parts of polyoxyethylene oleyl ether (Emulgen-430, manufactured by Kao Corporation) and 5 parts of N,N-dimethylcoconutamine acetate (Fermin DMC Acetate, manufactured by Kao Corporation) as an emulsifier to the mixture of Latex was obtained in the same manner as in Example 1.

Examples 6 to 10 Latexes were obtained using the urethane compounds of Synthesis Examples 6 to 10 in the same manner as in Example 5 using various vinyl monomers.

Comparative Examples 1 to 5 Milky white latex was obtained in the same manner as in the example except that the diisocyanate shown in Comparative Synthesis Examples 1 to 5 was used instead of polyisocyanate.

Comparative Example 6 100 parts of the urethane compound of Synthesis Example 1, 0.75 parts of polyoxyethylene nonylphenyl ether (Emulgen-920 manufactured by Kao Corporation) and 0.75 parts of N,N-dimethylstearylamine acetate (Armine DM 1 manufactured by Lion Corporation) as emulsifiers were added to 100 parts of the urethane compound of Synthesis Example 1.
2.5 parts of 8D acetate were added and dissolved by heating at 50°C, and 150 parts of 50°C warm water was added while stirring with a homomixer. Further, the mixture was treated with a high pressure homogenizer.

After this emulsification treatment, the solvent MIBK was distilled off under reduced pressure to obtain a milky white stable latex. Observation using an electron microscope confirmed that irregularly shaped particles with a diameter of 0.2 part m were formed.

Comparative Example 7 A urethane emulsion was obtained in the same manner as in Comparative Example 6, except that Emulgen-430 was used as an emulsifier instead of Emulgen-920 used in Comparative Example 6.

Comparative Example 8 30 parts of MMA, 50 parts of MIBK, 0.75 parts of polyoxyethylene nonylphenyl ether (Emulgen-920, manufactured by Kao Corporation) as an emulsifier, and N,N-dimethylstearylamine acetate (Deaf DM18D acetate, manufactured by Lion Corporation). 2.5 parts were added and dissolved by heating at 50°C, and 150 parts of 50°C warm water was added while stirring with a homomixer. Further, the mixture was treated with a high pressure homogenizer. Add 100 parts of this emulsion and 0.2 parts of azoisobutyronitrile as a polymerization initiator into a polymerization ampoule, and add 6 parts of this emulsion in an autoclave.
The reaction was carried out at 0°C for 20 hours. Monomer reaction rate is approximately 1
It was 00%. After the polymerization reaction, the solvent MI BK was distilled off under reduced pressure to obtain a milky white stable latex. This latex was designated as Comparative Example 8.

Comparative Example 9 A urethane emulsion was obtained in the same manner as in Comparative Example 8, except that Emulgen-430 was used as the emulsifier instead of Emulgen-920 used in Comparative Example 8.

Comparative Example 10 Comparative Example 10 was prepared by mixing 50 parts of the latex obtained in Comparative Example 6 and 50 parts of the latex obtained in Comparative Example 8.

Comparative Example 11 Comparative Example 11 was prepared by mixing 50 parts of the latex obtained in Comparative Example 7 and 50 parts of the latex obtained in Comparative Example 9.

Comparative Example 12 Polyfluoroalkylethyl acrylate: (CJan
*+CHiCHaOCOCH”CHt: nA=9)
[Abbreviated as FA] 40 parts, iBMA 55 parts, N-butoxymethylacrylamide; (CH, = CHC00NHCH, QC4H*) 5 parts, polyoxyethylene nonylphenyl ether (Emulgen-920 manufactured by Kao Corporation) 1.5 parts, N, N-dimethylstearylamine acetate (Deaf DM18 manufactured by Lion Corporation)
D acetate), 50 parts of acetone, and 300 parts of water were added and polymerized at 60°C for 7 hours using an azo-based water-soluble polymerization initiator (V-50 manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.) to obtain latex. Ta.

Water and oil repellent for leather of the present invention obtained above (Examples 1 to 1)
Chrome tanned cowhide leather treated using Comparative Examples 1 to 12 was subjected to water repellency, oil repellency, and dynamic water resistance tests.

The results are shown in Table 4.

The treatment and each test were conducted as follows.

1) Treatment: Put the water and oil repellent for leather shown in Table 4 into a drum, soak the chrome tanned cowhide leather in this drum, and heat at 50°C for 6 hours.
Processed for 0 minutes. After washing with water and drying, the pieces were rubbed in the usual manner, and then dried with a net at 70°C for 40 minutes, and then used for testing.

The water and oil repellent was diluted with tap water of po=s so that the concentration was 4 wt%.

2) Full Water/Oil Test and Dynamic Water Resistance Water repellency was determined by making the treated leather into a bag, filling it with water, and visually observing the state of water penetration 48 hours later.

Oil repellency is determined by placing a few drops of the test solution shown in Table 5 below on two locations on cowhide leather (diameter: approximately 4 mm) and determining the state of penetration after 30 seconds. (AATCCTMllg-19
66) Dynamic water resistance was determined by measuring the time required for water to penetrate using a new dynamic testing machine manufactured by Toyo Seiki. The number of bends was 60 times per minute.

Table 5: Oil repellency kit (AATC CTMllg-1966) [Effects of the invention] The water and oil repellent for leather of the present invention has excellent water and oil repellency for natural leather and synthetic leather compared to conventional water and oil repellents for leather. and its durability can be imparted. Additionally, dry cleaning durability, which was previously impossible to achieve, can be provided at the same time. In addition, it does not impair the texture of the leather itself, and since the particles are uniform and small, it has excellent film-forming properties and can provide sufficient effects with a short heat treatment. In addition, the improved stability makes it possible to use various other processing agents that have not been able to be used together in the past.

Claims (1)

[Scope of Claims] (Meta) obtained by reacting a polyfunctional isocyanate compound that is monofunctional or at least trifunctional, a hydroxyl compound containing a (meth)acroyl group or an allyl group, and a hydroxyl compound containing a polyfluoroalkyl group. Leather water and oil repellent agent 2 containing as an active ingredient a copolymer of a fluorine-containing urethane compound containing an acroyl group or an allyl group and a polyfluoroalkyl group and a copolymerizable compound other than this fluorine-containing urethane compound, fluorine-containing urethane Claim 1, wherein the compound is obtained by reacting a hydroxyl compound containing a polyfluoroalkyl group with a polyfunctional isocyanate compound, and then reacting the hydroxyl compound containing a (meth)acroyl group or an allyl group. The water and oil repellent agent 3 for leather contains copolymerizable compounds other than fluorine-containing urethane compounds (
The water and oil repellent agent 4 for leather according to claim 1, which contains a meth)acroyl group or an allyl group, and the fluorine-containing urethane whose copolymer contains a (meth)acroyl group or an allyl group and a polyfluoroalkyl group. Claim 1, which is obtained by dissolving the compound and a copolymerizable compound other than the fluorine-containing urethane compound in a water-insoluble organic solvent, emulsifying and dispersing it in water, and after polymerization, distilling off the solvent. Water-dispersible leather water and oil repellent described above