JPH0819325B2 - Polyurethane emulsion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyurethane emulsion, which has surface lubricity, water repellency (water pressure resistance), stain resistance, washing durability, mechanical properties,
An object of the present invention is to provide a polyurethane emulsion which is capable of providing a porous sheet material having excellent properties such as water vapor permeability and a good feeling.

(Prior Art) Conventionally, a large number of porous sheet materials made of polyurethane resin and methods for producing the same have been known as substitutes for natural leather and the like, and they are roughly classified into a wet method and a dry method.

(Problems to be Solved by the Invention) Both methods have advantages and disadvantages, and the dry method is superior in terms of productivity. As such a dry method,
JP-B-48-4380, JP-B-48-8742, JP-A-Showa
JP-A-51-41063, JP-A-54-66961 and JP-A-54-66961
The method described in Japanese Patent No. 68498 is known.

According to these known methods, respectively, excellent porous sheet materials having excellent moisture permeability are provided. However, since these porous sheet materials are porous, it is a matter of course that the surface lubricity is high. In addition, there is a problem that the feeling is inferior and the soil is more likely to be soiled.

In addition, since the fine pores of these porous sheets are communicating holes for the purpose of moisture permeability, it is easy for water to enter from the outside, so when used in rainy weather, water penetrates into the inside. There is a problem that the inside gets wet.

As a method for solving such a problem, a method of incorporating a so-called softening agent or water repellent such as a fluorocarbon compound or a fluorine compound in the porous layer is widely used,
Since the softening agents and water repellents as described above are relatively low molecular weight compounds and have poor compatibility with polyurethane resins, they bleed out on the surface of the porous layer over time and the surface becomes sticky. In addition, there arises a problem of contamination that dust is likely to adhere.

Further, by repeating the washing, the softener and the water repellent are removed, and the performance of the surface smoothness, hand, water repellency (water pressure resistance), and stain resistance imparted by the softener and the water repellent is lost. There is a problem of durability.

Therefore, development of a porous sheet material that is porous and has excellent surface lubricity, good feeling, water pressure resistance, stain resistance and washing durability is demanded.

As a result of earnest research to meet the above-mentioned demands, the present inventor has solved the above-mentioned drawbacks of the prior art when using a specific polyurethane emulsion, and is a porous sheet material that can sufficiently meet the above-mentioned demands of the industry. The present invention has been completed by finding that it can be provided.

(Means for Solving Problems) That is, the present invention is a polyurethane resin containing no silicon atom having a fluorocarbon segment in the main chain and / or side chain (provided that both ends are fluorocarbon segments, Excluding polyurethane-based resin in which the segment (1) and at least two urethane bonds and a urethane oligomer having a hydrophilic molecular chain are linked by a urethane bond)
Is a polyurethane emulsion characterized by being obtained by emulsifying water in a solution of an organic solvent.

(Operation) Next, the present invention will be described in more detail. The present inventor has found that the above-mentioned problems of the prior art are due to a specific polyurethane-based resin, that is, a main chain and / or a side chain for forming the porous layer. It was discovered that the problem can be solved by using a polyurethane resin having a fluorocarbon segment.

That is, in the present invention, the fluorocarbon compound as the softening agent or the water repellent is included in the polyurethane by a covalent bond, so that the softening agent or the water repellent may be surface-treated with time even after the formation of the porous layer. It does not bleed out and is not removed by washing, and can almost permanently retain excellent surface smoothness, high flexibility, water pressure resistance, stain resistance, washing resistance, etc. .

(Preferred Embodiment) The present invention will be described in more detail with reference to preferred embodiments of the present invention.

The polyurethane-based resin used in the present invention and having a fluorocarbon segment, which is the main feature of the present invention, is a polyol, a polyisocyanate, a chain extender, or the like when a polyurethane-based resin is obtained by reacting the polyol, the polyisocyanate or the chain extender. All or part of the agent is obtained by using a fluorocarbon compound having a reactive functional group such as an amino group, an epoxy group, a hydroxyl group, a carboxyl group, and a thioalcohol group.

Preferred examples of the fluorocarbon compound having such a reactive organic functional group include the following compounds.

(1) H (CF ₂ CF ₂ ) _n CH ₂ OH (n = 1 to 7) (2) CF ₃ (CF ₂ CF ₂ ) _n CH ₂ CH ₂ OH (n = 1 to 10) (3) CF ₃ (CF ₂ CF ₂ ) _n COOH (n = 1 to 10) (4) CF ₃ (CF ₂ CF ₂ ) _n CH ₂ CH ₂ SH (n = 1 to 10) (5) H (CF ₂ CF ₂ ) ₁ (CH ₂ ) _m (OCH ₂ CH ₂ (OH) CH ₂ ) _n OH
(1 = 1 to 10, m = 1 to 10, n = 1 to 3) (6) F (CF ₂ CF ₂ ) ₁ (CH ₂ ) _m (OCH ₂ CH ₂ (OH) CH ₂ ) _n OH
(1 = 1 to 10, m = 1 to 10, n = 1 to 3) The fluorocarbon compound having a reactive organic functional group as described above is an example of a preferable fluorocarbon compound in the present invention. The invention is not limited to these exemplifications, and the above-exemplified compounds and other fluorocarbon compounds are currently commercially available and can be easily obtained from the market, and both are used in the present invention. It is possible.

Further, a fluorocarbon compound as described above and a polyisocyanate as described below, an intermediate obtained by reacting so that at least one of the reactive group of the fluorocarbon compound or the isocyanate group of the polyisocyanate group remains, for example, A difunctional fluorocarbon compound and a polyfunctional polyisocyanate reacted with an isocyanate group rich, or conversely, an intermediate obtained by reacting the fluorocarbon compound with a rich reactive group can be similarly used. .

Further, when the reactive group of the fluorocarbon compound is a hydroxyl group, an amino group, a carboxyl group, an epoxy group or the like, a polyester polyol obtained by reacting with a polyol, a chain extender or a polyvalent carboxylic acid or a polyamine as described below. , Polyamide polyamine, polyether polyol and the like can be used in the same manner.

As the polyol, any conventionally known polyol for polyurethane can be used.For example, polyethylene adipate having a hydroxyl group as a terminal group and having a molecular weight of 300 to 4,000, polyethylene propylene adipate, polyethylene butylene adipate, polydiethylene adipate, polydiethylene adipate, poly Butylene adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, polytetramethylene ether glycol, poly-ε-caprolactone diol, polyhexamethylene adipate, carbonate polyol, polypropylene glycol, etc. And those containing an appropriate amount of polyoxyethylene chains.

As the organic polyisocyanate, any conventionally known one can be used, but preferred examples include 4,4′-diphenylmethane diisocyanate (MDI), water-added MDI, isophorone diisocyanate, 1,3-xylylene diisocyanate, 1 , 4-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, etc., or these organic polyisocyanates Urethane prepolymers obtained by reacting low molecular weight polyols and polyamines to form terminal isocyanates can of course be used.

As the chain extender, any of those conventionally known can be used. For example, preferred are ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, ethylenediamine, 2-propylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, isophoronediamine, m-xylylenediamine, hydrazine, water and the like.

Any of the fluorocarbon segment-containing polyurethane-based resins obtained from the materials as described above can be used in the present invention, but preferred ones are those in which the silicone segment accounts for about 0.2 to 50% by weight in the molecule. If the carbon segment is less than about 0.2% by weight, the intended purpose of the present invention will not be achieved sufficiently, and if it exceeds about 50% by weight, problems such as deterioration of adhesiveness will occur, which is not preferable.

Preferred are those having a molecular weight of 20,000 to 500,000, and most preferred are those having a molecular weight of 20,000 to 250,000.

The fluorocarbon segment-containing polyurethane resin as described above can be easily obtained by a conventionally known production method. These polyurethane-based resins may be prepared without a solvent or may be prepared in an organic solvent,
In terms of steps, it is advantageous that the polyurethane emulsion can be used as it is for the preparation of the polyurethane emulsion by preparing it in an organic solvent to be prepared, that is, an organic solvent having a certain degree of mutual solubility with water. .

Preferred as such an organic solvent are methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, and the like. Acetone, cyclohexane, tetrahydrofuran, dioxane, methanol, ethanol,
Isopropyl alcohol, butanol, toluene, xylene, dimethylformamide, dimethyl sulfoxide,
Perchlorethylene, trichloroethylene, methyl cellosolve, butyl cellosolve, cellosolve acetate and the like can also be used. Those having no or no solubility in water in these organic solvents are used as a mixture with other organic solvents with a limit in the mutual solubility with water. The above organic solvents can of course be used as mixed organic solvents.

By preparing a polyurethane-based resin in such an organic solvent, a polyurethane-based resin solution can be obtained, and its solid content is about 5% by adding or removing the same or another solvent.
Conveniently it is in the range of from 60 to 60% by weight. In the present invention, the polyurethane resin may be a solution sufficiently dissolved in an organic solvent, or a dispersion in which the resin is partially or entirely precipitated (hereinafter simply referred to as a solution).

To prepare a polyurethane emulsion from the above polyurethane solution, an appropriate amount of a water-in-oil emulsifier is added to the above polyurethane solution, if necessary, while stirring it vigorously. It can be obtained by adding a subsaturated amount of water, for example, about 50 to 500 parts by weight of water per 100 parts by weight of the solid content in the solution.

As the emulsifier, any of the conventionally known water-in-oil emulsifiers can be used, but a particularly suitable emulsifier is a polyurethane-based interfacial lubricant having an appropriate amount of polyoxyethylene chain in the molecule. The emulsifier is preferably used in an amount of about 1 to 10 parts by weight per 100 parts by weight of the solid content of the polyurethane resin solution.

The polyurethane emulsion thus obtained is a milky creamy fluid, and maintains a stable state even when left as it is for several months. Such a polyurethane emulsion may optionally contain various additives, for example, known additives such as a coloring agent, a crosslinking agent, a stabilizer, and a filler.

Examples of the substrate used for producing the porous sheet from the polyurethane emulsion as described above include various bases such as various woven fabrics, knitted fabrics, non-woven fabrics, release papers, plastic films, metal plates and glass plates. You can use wood.

The polyurethane emulsion may be applied to the substrate by any known method such as coating method, dipping method, and combination method thereof, and the impregnation and / or coating amount thereof is about 5 to 2,000 g ( It can be varied in a wide range depending on the purpose, such as a compounded solution) / m ² .

The gelation and drying of the substrate impregnated and / or coated with the above polyurethane emulsion may be the same as in the prior art, and for example, at a temperature of about 40 to 200 ° C. for several minutes to several hours. Upon drying, a polyurethane porous sheet material having excellent properties is obtained.

(Effect) The porous sheet material obtained by using the polyurethane emulsion of the present invention as described above has a very fine pore structure,
Has excellent physical properties and excellent water vapor permeability,
It is useful as a material for various kinds of synthetic leather such as clothes, shoes, waterproof cloths, tents, wallpaper, flooring materials, filtration materials, filters for air conditioners and the like.

In particular, the polyurethane-based resin in the polyurethane emulsion of the present invention contains a fluorocarbon segment in the main chain and / or side chain of its molecule, so that even if a porous layer is formed from the emulsion. , The fluorocarbon segment in the porous layer does not bleed out to the surface of the porous layer over time, and thus semipermanently retains excellent surface smoothness, texture, water pressure resistance, stain resistance and washing durability. It is possible.

Next, the present invention will be specifically described with reference to Reference Examples, Examples, Use Examples and Comparative Examples. In addition, in the text, "%" and "%" are based on weight.

Reference Example 1 (Production Example of Intermediate) 52 parts of an adduct of hexamethylene diisocyanate and water (Duranate 24A-100, manufactured by Asahi Kasei, NCO% 23.5) was added at 60 ° C.
While stirring well, 53 parts of fluorinated alcohol having the following structure was gradually added dropwise to the mixture, and the mixture was reacted to obtain 103 parts of a colorless and transparent liquid intermediate (M1).

H (CF ₂ CF ₂ ) ₅ OH The infrared absorption spectrum of this intermediate shows 2270 / cm
Absorption by free isocyanate groups of
An absorption band due to the -CF ₂ -group was shown at / cm. Further, when the free isocyanate groups in this intermediate were quantified, the theoretical value was 2.65%, whereas the measured value was 2.51%.

Therefore, the main structure of the above intermediate is presumed to be the following formula.

Reference Example 2 (Production Example of Intermediate) 120 parts of an adduct of 1 mol of trimethylolpropane and 3 mol of tolylene diisocyanate (TDI) (Coronate L, made by Nippon Polyurethane, NCO% 12.5, solid content 75%) at 50 ° C.
After stirring well, 114 parts of fluoroalcohol having the following structure is gradually added dropwise to this and reacted.

After the completion of the CF ₃ (CF ₂ CF ₂ ) ₃ OH reaction, 198 parts of a transparent liquid intermediate (M2) was obtained.

According to the infrared absorption spectrum of this intermediate, 2270 / cm
Absorption by free isocyanate groups of
An absorption band due to the -CF ₂ -group was shown at / cm. Further, when the free isocyanate group in this intermediate was quantified, the theoretical value was 2.83%, whereas the measured value was 2.68%.

Therefore, the main structure of the above intermediate is presumed to be the following formula.

Reference Example 3 (Production Example of Intermediate) 186 parts of an adduct of 1 mol of trimethylolpropane and 3 mol of xylylene diisocyanate (Takenate D110N, Takeda Yakuhin, NCO% 11.5, solid content 75%) is stirred well at room temperature. Then, 172 parts of a fluorinated alcohol having the following structure was gradually dropped into this and reacted.

CF ₃ (CF ₂ CF ₂ ) ₃ CH ₂ CH ₂ SH After the reaction was completed, 320 parts of a transparent liquid intermediate (M3) was obtained.

According to the infrared absorption spectrum of this intermediate, 2270 / cm
Absorption by free isocyanate groups of
An absorption band due to the -CF ₂ -group was shown at / cm. When the free isocyanate group in this intermediate was quantified, the theoretical value was 2.69%, while the measured value was 2.51%.

Therefore, the main structure of the above intermediate is presumed to be the following formula.

Reference Example 4 (Modification of resin ... Side chain) 1,000 parts of polyethylene adipate (average molecular weight about 1,000, hydroxyl value 112), 144 parts of 1,4-butanediol, 1,144 parts of methyl ethyl ketone and 650 parts of diphenylmethane diisocyanate were reacted at 70 ° C. for 8 hours. Thereafter, 3,042 parts of methyl ethyl ketone was further added and homogenized, and the mixture was cooled to room temperature with stirring to obtain a milky white polyurethane dispersion having a solid content of 30%. 5 parts of the intermediate of Reference Example 1 was added to this polyurethane dispersion and reacted at 70 ° C. for 4 hours to obtain a milky white modified resin liquid (1) in which the intermediate and the polyurethane resin were bonded.

The modified resin obtained above did not show any isocyanate group by infrared absorption spectrum. It is presumed that this is an intermediate grafted to the resin.

Reference Example 5 (Modification of resin: side chain) 1,4-butane ethylene adipate (average molecular weight: about 1,00)
0, hydroxyl value 112) 1,000 parts, 1,4-butanediol 144
Part, methyl ethyl ketone 1,144 parts and diphenylmethane diisocyanate 650 parts were reacted at 70 ° C. for 8 hours, and then 3.00 parts.
42 parts of methyl ethyl ketone was added and homogenized, and cooled to room temperature with stirring to obtain a milky white polyurethane dispersion having a solid content of 30%. To 100 parts of this polyurethane dispersion, 5 parts of the intermediate of Reference Example 2 was added and reacted at 70 ° C. for 4 hours to obtain a milky white modified resin liquid (2) in which the intermediate and the polyurethane resin were bonded.

The modified resin obtained above did not show any isocyanate group by infrared absorption spectrum. It is presumed that this is an intermediate grafted to the resin.

Reference Example 6 (Modification of resin ... Side chain) 1,6-hexamethylene adipate (average molecular weight of about 2,000
0, hydroxyl value 56) 1,000 parts, 1,4-butanediol 125 parts and diphenylmethane diisocyanate 472 parts were added to methyl ethyl keto 1,200 parts and reacted at 70 ° C. for 8 hours, and then further added for 2,5
26 parts of methyl ethyl ketone was added and homogenized, and the mixture was cooled to room temperature with stirring to obtain a milky white polyurethane dispersion having a solid content of 30%. To 100 parts of this polyurethane dispersion, 5 parts of the intermediate of Reference Example 3 was added and reacted at 70 ° C. for 4 hours to obtain a milky white modified resin liquid (3) in which the intermediate and the polyurethane resin were bonded.

The modified resin obtained above did not show any isocyanate group by infrared absorption spectrum. It is presumed that this is an intermediate grafted to the resin.

Reference Example 7 (Modification of resin ... Side chain) Polytetramethylene glycol (average molecular weight about 1,00
0, hydroxyl value 112) 1,000 parts, ethylene glycol 93 parts and diphenylmethane diisocyanate 625 parts in 1,500 parts of methyl ethyl ketone, reacted at 60 ° C. for 8 hours, further added 2,500 parts of methyl ethyl ketone, cooled to room temperature with stirring, A milky white polyurethane dispersion (4) having a solid content of 30% was obtained. To 100 parts of this polyurethane dispersion, 5 parts of the intermediate of Reference Example 2 was added and reacted at 60 ° C. for 4 hours to obtain a milky white modified resin liquid (4) in which the intermediate and the polyurethane resin were bonded.

The modified resin obtained above did not show any isocyanate group by infrared absorption spectrum. It is presumed that this is an intermediate grafted to the resin.

Reference Example 8 (Modification of resin ... Side chain) Polycarbonate polyol (average molecular weight about 2,000,
Hydroxyl value 56) 1,000 parts, ethylene glycol 86 parts and diphenylmethane diisocyanate 509 parts were added to methyl ethyl ketone 1,200 parts, and after reacting at 70 ° C for 8 hours, further 2,5
22 parts of methyl ethyl ketone was added and homogenized, and cooled to room temperature with stirring to obtain a milky white polyurethane dispersion having a solid content of 30%. 5 parts of the intermediate of Reference Example 3 was added to 100 parts of this polyurethane dispersion and reacted at 70 ° C. for 4 hours to obtain a milky white modified resin solution (5) in which the intermediate and the polyurethane resin were bonded.

The modified resin obtained above did not show any isocyanate group by infrared absorption spectrum. It is presumed that this is an intermediate grafted to the resin.

Reference Example 9 (Modification of resin: main chain) 1,4-butane ethylene adipate (average molecular weight: about 1,00)
0, hydroxyl value 112) 1,000 parts, 50 parts of a fluorocarbon compound having the following structure, 31 parts of 1,4-butanediol and 371 parts of diphenylmethane diisocyanate are added to 3,388 parts of methyl ethyl ketone and reacted at 70 ° C. for 8 hours to give an average molecular weight of A polyurethane resin solution having a solid content of 30% of 62,000 was obtained.

Next, 130 parts of ethylene glycol and 524 parts of diphenylmethane diisocyanate were added to the above resin solution, and the temperature was changed to 60 ° C.
After reacting for 10 hours, add 1,526 parts of methyl ethyl ketone to homogenize and cool to room temperature with stirring. The average molecular weight of polyurethane is 131,000, and the particle size of precipitated particles is 1 μm or less. Solid content 30% A milky white polyurethane dispersion (6) was obtained.

Reference Example 10 (Modification of resin: main chain) Polytetramethylene glycol (average molecular weight about 1,00
0, hydroxyl value 112) 1,000 parts, 100 parts of a fluorocarbon compound having the following structure, 24 parts of ethylene glycol and 393 parts of diphenylmethane diisocyanate are added to 3,540 parts of methyl ethyl ketone and reacted at 70 ° C. for 9 hours to give an average molecular weight of 51,000. A polyurethane resin solution having a solid content of 30% was obtained.

Subsequently, 116 parts of ethylene glycol and 465 parts of diphenylmethane diisocyanate were added to the resin solution,
After 10 hours of reaction, 1,356 parts of methyl ethyl ketone was added to homogenize, and the mixture was cooled to room temperature with stirring. The average molecular weight of polyurethane was 105,000, and the precipitated particles had a particle size of 1 μm or less. Solid content 30% A milky white polyurethane dispersion (7) was obtained.

Reference Example 11 (Modification of resin: main chain) 1,6-hexamethylene adipate (average molecular weight of about 2,000
0, hydroxyl value 56) 2,000 parts, fluorocarbon compound with the following structure
100 parts, 20 parts of 1,4-butanediol and 340 parts of diphenylmethane diisocyanate were added to 5,740 parts of methyl ethyl ketone and reacted at 70 ° C. for 9 hours to give a polyurethane resin solution having an average molecular weight of 75,000 and a solid content of 30% (C ) Got.

Next, 390 parts of trimethylolpropane and 1,091 parts of diphenylmethane diisocyanate were added to the above resin solution, and after reacting at 60 ° C. for 10 hours, 3,456 parts of methyl ethyl ketone were further added to homogenize and cooled to room temperature with stirring, and the average molecular weight of polyurethane was 180,000. 1,000, solid content 30%
A milky white polyurethane dispersion (8) was obtained.

Examples 1 to 8 The products of Examples 1 to 8, the emulsifier, the organic solvent, and water were stirred with a homomixer to prepare the following polyurethane emulsions of the present invention.

Example 1; Polyurethane emulsion (1) Polyurethane solution (1) 100 parts Urethane emulsifier 2 parts Methyl ethyl ketone 20 parts Xylene 20 parts Water 85 parts Example 2; Polyurethane emulsion (2) Polyurethane solution (2) 100 parts Urethane emulsifier 2 parts Methyl ethyl ketone 20 parts Toluene 20 parts Water 80 parts Example 3; Polyurethane emulsion (3) Polyurethane solution (3) 100 parts Urethane emulsifier 2 parts Methyl ethyl ketone 150 parts Toluene 20 parts Water 80 parts Example 4; Polyurethane emulsion (4) Polyurethane solution (4) 100 parts PO / EO block polymer type emulsifier 4 parts Dioxane 10 parts Toluene 10 parts Xylene 20 parts Water 70 parts Example 5; Polyurethane emulsion (5) Polyurethane solution (5 ) 100 parts Urethane emulsifier 1 part Methyl isobutyl ketone 20 parts Toluene 20 parts Water 75 parts Example 6; Polyurethane emulsion (6) Polyurethane solution (6) 100 parts PO / EO block copolymer type emulsifier 1 part Tetrahydrofuran 20 parts Toluene 20 parts Water 60 parts Example 7; Polyurethane emulsion (7) Polyurethane solution (7) 100 parts Urethane emulsifier 2 parts Methyl ethyl ketone 20 Parts xylene 20 parts water 85 parts Example 8; Polyurethane emulsion (8) Polyurethane solution (8) 100 parts Urethane emulsifier 2 parts Methyl ethyl ketone 20 parts Toluene 20 parts Water 80 parts Comparative Examples 1 to 8 In Examples 1 to 8 Instead of the fluorocarbon segment-containing polyurethane-based resin, a polyurethane-based resin solution having no fluorocarbon segment prepared in the same manner as in Reference Examples 4 to 11 was used, and otherwise the same as in Examples 1 to 8, The polyurethane emulsions of Comparative Examples 1 to 8 were prepared.

The properties of the polyurethane emulsions of Examples 1 to 8 and Comparative Examples 1 to 8 are as shown in Table 1 below.

Use Examples 1 to 8 Various polyurethanes having the characteristics shown in Table 3 below were obtained by impregnating and / or coating various substrates with the polyurethane emulsion shown in Table 1 under the conditions shown in Table 2 below. To obtain a porous sheet material. Note that Comparative Use Examples 1 to 8 were performed under the same conditions as Use Examples 1 to 8, respectively.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsumi Kuriyama 1135-1, Kuri Shioma, Koshigaya, Saitama (56) References JP 62-218471 (JP, A) JP 62-181385 (JP, A) ) JP-A-52-123493 (JP, A) JP-B-45-37868 (JP, B2)

Claims (2)

[Claims] 1. A polyurethane resin which does not contain a silicon atom having a fluorocarbon segment in its main chain and / or side chain (provided that both ends are fluorocarbon segments, and these segments and at least two urethanes). Polyurethane emulsion obtained by emulsifying water in an organic solvent solution of a polyurethane resin in which a bond and a urethane oligomer having a hydrophilic molecular chain are linked by a urethane bond). 2. The polyurethane emulsion according to claim 1, wherein the amount of the fluorocarbon segment is 0.2 to 50% by weight in the total amount of the polyurethane resin.