JP2002179758A - Polyurethane emulsion, and synthetic leather/artificial leather manufactured by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a polyurethane emulsion suitable for manufacturing synthetic leather/artificial leather having excellent heat stability, weatherability, resistance to hydrolysis, oleic acid resistance and, among others, foldability and flexibility both at low temperatures, and to obtain an artificial leather manufactured by using the polyurethane emulsion. SOLUTION: This polyurethane emulsion comprises a reaction product of a urethane prepolymer comprising (1) an organic diisocyanate, (2) a polycarbonatediol with specified structural components and (3) a compound having a hydrophilic center group and at least two isocyanate-reaction center groups and a chain extender. The synthetic leather and an artificial leather are manufactured by using the polyurethane emulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyurethane emulsion which provides synthetic leather and artificial leather having excellent weather resistance, hydrolysis resistance and oleic acid resistance, as well as excellent low-temperature flexibility, and produced using the polyurethane emulsion. It relates to synthetic leather and artificial leather.

[0002]

2. Description of the Related Art Polyurethane emulsions provide coatings having abrasion resistance, adhesion, non-adhesion, and rubber elasticity, and are used for flooring, wall materials, carpentry, carpets, construction, nonwoven fabrics, and textile coatings. Agents, glass fiber sizing agents, paints (for automobiles, construction, etc.), adhesives (for buildings,
It has been widely used as a coating agent for vinyl, artificial leather, synthetic leather, and the like. Polycarbonate-based polyurethane emulsions were recognized for their advantages such as hydrolysis resistance, heat resistance, and abrasion resistance. And its use in paints, synthetic leathers, artificial leathers and the like obtained therefrom is also expanding.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating material, an adhesive and a coating material which are excellent in low-temperature flexibility while maintaining properties such as hydrolysis resistance and oleic acid resistance. An object of the present invention is to provide a polyurethane emulsion, and to provide a synthetic leather and an artificial leather further excellent in low-temperature flexibility while maintaining excellent properties such as hydrolysis resistance and oleic acid resistance.

[0004]

Means for Solving the Problems In order to solve the above-mentioned technical problems, the present inventors have established a relationship between a polycarbonate diol as a diol component of a polyurethane emulsion to be used and the obtained polyurethane emulsion,
Further, the relationship between the physical properties of synthetic leather and artificial leather manufactured using the polyurethane emulsion was examined in detail by measuring a scale suitable for practical use. As a result, it has been found that the chemical structure of the polycarbonate diol has an unexpectedly strong effect on the product properties required for the above-mentioned applications, and that the control of the structure is important. After further study, the present invention was completed.

That is, the present invention provides: (1) organic diisocyanate, (2) polycarbonate diol, (3) one hydrophilic center and at least 2
In a polyurethane emulsion comprising a reaction product of a urethane prepolymer comprising a compound having a group of two isocyanate-reactive centers and a chain extender, the polycarbonate diol (2) comprises the following (A), (B) and (C) ) Polyurethane emulsion

[0006]

Embedded image

(Where m and n are integers of 4 to 6, and m = n
Or m ≠ n, R ′ is an ethylene group, R ″ is an alkylene group having 2 to 6 carbon atoms, the ratio of (A) and (B) is 9: 1 to 1: 9 (molar ratio), (A), (B),
(C) is contained in an amount of 0.2 to 7 mol% based on the total amount of (C).)

[0008] 2. 1. And synthetic leather and artificial leather produced using the polyurethane emulsion described in 1. above.

The physical properties of the film obtained from the polyurethane emulsion are as follows: adhesives, paints, coating materials, synthetic leather, artificial leather, especially synthetic leather, car seats in artificial leather, sports shoes, furniture, clothing (for sportswear, etc.). Items such as low-temperature flexibility, low-temperature flexibility, and oleic acid resistance have become important in applications. The effects of the molecular structure of the polycarbonate diol on these various properties were examined based on a practical test method. The type of glycol used, the component ratio of the copolycarbonate diol, and the content of the component (C) were not limited. When the amount is 0% or more than about 7% with respect to the total amount of (A), (B) and (C), when the amount is in the range of 0.2 to 7%, It was found that low-temperature flexibility and low-temperature flexibility were commonly improved for polycarbonate diols. Further, if the content of the oxyethylene group is larger than 7%, the oleic acid resistance generally decreases or worsens.

As described above, in the present invention, by controlling the content of the component (C) within the above range, an adhesive, paint, coating material,
The molecular structure requirements of polycarbonate diols to provide polyurethane emulsions that can be made into synthetic leather, artificial leather, especially car seats, sports shoes, furniture, clothing, etc.

Heretofore, the content of the constituent component (C) in the polyurethane emulsion has been determined in the production process in order to satisfy other essential conditions.

[0012] However, the requirements from the standard aspect of the product have become extremely severe and important in recent years, and as a result of an experimental study on the generation of (C), Thus, knowledge was obtained on the effect of the formation and content of (C) on the physical properties, and a control method was further established. The control method will be described in detail in the production of the polycarbonate diol described below,
In the case where ethylene carbonate is used as a carbonate-forming agent, the control has conventionally been introduced all at once into a reaction system. By introducing the ethylene carbonate within a certain time while continuously reacting it, (C) It controls the amount of generation.

The polycarbonate diol used in the present invention is preferably an aliphatic polycarbonate diol.
In particular, an amorphous aliphatic polycarbonate diol is preferred. These are produced by a known method.Several types are known, and an aliphatic diol is reacted with a dialkyl carbonate, a diaryl carbonate, a carbonate monomer selected from alkylene carbonates, and particularly preferably ethylene carbonate. Is a polycarbonate having a terminal hydroxyl group, that is, a polycarbonate diol.

As the aliphatic diol used herein, generally, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, (1,6-cyclohexane) Hexanediol),
These derivatives, mixtures thereof, and the like are used. Polycarbonate diols obtained from 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol are hereinafter referred to as C4PCDL, C5PCDL, C6PCDL,
Copolycarbonate diols of 1,4-butanediol and 1,6-hexanediol are abbreviated as C4C6PCDL, and copolycarbonate diols of 1,5-pentanediol and 1,6-hexanediol are abbreviated as C5C6PCDL.

The organic diisocyanate used in the present invention includes, for example, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate and its mixture (TDI), diphenylmethane-4,4'-diisocyanate (MDI), naphthalene-1,5-diisocyanate (NDI), 3,3'-dimethyl-4,4 Aromatic diisocyanates such as' -biphenylene diisocyanate (TODI) and polymethylene polyphenyl diisocyanate; aromatic alicyclic diisocyanates such as xylylene diisocyanate (XDI) and phenylene diisocyanate; and 4,4'-methylene biscyclohexyl diisocyanate Aliphatic diisocyanate such as MDI), isophorone diisocyanate (IPDI), cyclohexane diisocyanate (hydrogenated XDI), and hexamethylene diisocyanate (HDI). Aliphatic diisocyanates are preferred from the viewpoint of weather resistance.

In a compound having one hydrophilic center and at least two isocyanate-reactive center groups, the hydrophilic center is, for example, a carboxylic acid group or a sulfonic acid group, which can be neutralized with an alkaline group. Represents a group. Further, the group of the isocyanate-reactive center is an alcohol,
A group that generally reacts with an isocyanate such as an amine to form a urethane bond or a urea bond. Specifically, for example, the following formula

[0017]

Embedded image (Wherein R is an alkyl group having 1 to 3 carbon atoms)

A diol represented by, for example, 2,2 '
-Dimethylolpropionic acid, 2,2-methylolbutyric acid, and 2,2'-dimethylolvaleric acid.
Also, diaminocarboxylic acids, such as lysine, cystine, and 3,5-diaminocarboxylic acid, may be mentioned. When these are actually used, they are neutralized with amines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine and triethanolamine, sodium hydroxide, potassium hydroxide, ammonia and the like. Naturally, a suitable surfactant,
For example, higher fatty acids, resin acids, acid fatty alcohols,
Anionic surfactants such as sulfates, higher alkyl sulfonates, higher alkyl sulfonates, alkylaryl sulfonates, sulfonated castor oil, sulfosuccinates, and the like, or ethylene oxide and long-chain fatty alcohols or phenols Emulsion stability may be maintained by using a nonionic surfactant represented by a known reaction product in combination.

Examples of the chain extender used in the present invention include short-chain diols such as ethylene glycol and 1,4-butanediol, ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diphenyldiamine. , Diaminodiphenylmethane, diaminohexylcyclohexylmethane, piperazine, 2-methylpiperazine, various diamines such as isophoronediamine and water,

The polyurethane emulsion of the present invention is obtained, for example, by reacting an organic diisocyanate, a polycarbonate diol, and a compound having one hydrophilic center and at least two isocyanate-reactive groups,
An NCO-terminated urethane prepolymer is obtained.

This reaction can be generally carried out in a solvent using an organic solvent inert to isocyanates such as acetone, methyl ethyl ketone, toluene, dioxane, dimethylformamide, N-methylpyrrolidone and tetrahydrofuran.

Next, if necessary, the obtained prepolymer is neutralized, dispersed in water, and made high molecular weight by reaction with a chain extender. When the prepolymer reaction is performed using a solvent, for example, it is necessary to remove the solvent by a method such as distillation under reduced pressure after completion of the chain extension reaction.

Next, the production of artificial leather produced from the polyurethane emulsion thus obtained and its physical properties will be described.

It is widely known that various kinds of polymer compounds are applied to a non-woven sheet material mainly composed of ultrafine fibers to obtain synthetic leather and artificial leather. An elastic polymer compound such as polyurethane, which is suitable for giving physical properties such as texture, durability, and dimensional stability, is used. In particular, in recent years, the use of various water-based polyurethane emulsions without using an organic solvent has been studied.

At the same time, a polyurethane emulsion as an adhesive or a paint is also useful, and it will be described later that the polyurethane emulsion of the present invention exhibits particularly preferable performance in the field of application.

The non-woven sheet used in the production of the artificial leather of the present invention preferably has a surface layer having a fiber layer mainly composed of ultrafine fibers of 0.5 denier or less. For example, the entire nonwoven sheet may be composed of a fiber layer having the same configuration as the surface fiber layer, and a layer connected to the surface layer fiber is entirely covered on one side with the surface fiber layer, and is three-dimensionally entangled. You may arrange | position the layer which consists of a knitted fabric. The fiber material of the ultrafine fibers having a density of 0.5 denier or less is not particularly limited, but usually, for example, polyethylene terephthalate, nylon 6, nylon 66, polyacrylonitrile, rayon, and the like are used.

The surface of such a non-woven sheet is buffed with emery paper, sand roll, or the like, and
It is immersed in a liquid obtained by mixing a water-soluble polymer compound as described below and the polyurethane emulsion of the present invention, then taken out, squeezed, appropriately adjusted for the impregnation amount of the mixture, and dried by heating. The resulting product does not have raised hair, but this sheet-like composite is placed in hot water to extract a water-soluble polymer compound, washed with water and dried to obtain a suede-like artificial leather.

Examples of the water-soluble polymer compound include methyl cellulose, carboxymethyl cellulose,
Hydroxymethyl cellulose, casein, partially saponified or partially saponified polyvinyl alcohol, polyacrylamide, polyacrylic acid and the like are used.

The following items are generally evaluated with respect to the suede-like artificial leather thus obtained. Flexibility: JIS L1079 A method (45 cantilever method) Wrinkle resistance: JIS L1079 A method (wire method) Peel strength: Peel off the nonwoven fabric layer from one end of the sample leather and measure the peel strength with a Tensilon type tensile tester Hydrolysis resistance: The final product is immersed in hot water at 100 ° C for 30 minutes, the peel strength is measured, and the strength retention before and after immersion is indicated by the following criteria. Retention rate exceeds 85% ○ 50-85% △ Less than 50% ×

Although the above is generally used as an inspection standard for artificial leather, the artificial leather of the present invention is naturally evaluated as ○. About the artificial leather in the present invention,
It is an object of the present invention to manufacture products that meet these strict requirements such as those for car seats, furniture, clothing, sports shoes, etc., in accordance with the following inspection standards, and in particular, to meet these requirements. .

Low temperature flexibility: 100,000 at -35 ° C
◎ are those that can withstand repeated bending repeatedly.
Somewhat satisfied were expressed as 、, and some were unsatisfactory as △. Oleic acid resistance: It is often used as an indicator of sweat resistance. After the leather sample is immersed in oleic acid at room temperature for one week, the tackiness of the surface is evaluated by finger touch.も の indicates good, ○ indicates slightly satisfactory, 満 足 indicates slightly unsatisfactory, and × indicates unsatisfactory.

Here, the above-mentioned evaluation of the required artificial leather is based on the polyurethane emulsion used for producing leather,
Further investigation revealed that the molecular structure of the polycarbonate diol used in the production of the polyurethane emulsion was greatly affected by the field test. The low-temperature flexibility, which is particularly important, depends on the content of the above component (C). More specifically, the content is as low as (A), (B),
When the content was 0.2 to 7% with respect to the total amount of (C), it could be understood that the most preferable result was obtained, and the present invention was reached. If this unit exceeds 7%, for example 10%, it has been found that the oleic acid resistance decreases. As for synthetic leather, it is manufactured by a generally known method and as a result of evaluating its physical properties,
Similar results were obtained with artificial leather. Next, the present invention will be described with reference to Examples and Comparative Examples.

Example 1 (Production of polycarbonate diol) Jacket, stirring
Equipment, a vacuum pump and a rectification column packed with structured packing.
The obtained 30 l reactor was used for polymerization (see FIG. 1).
7.5 kg of 1,5-pentanediol, 1,6-hexane
8.1 kg of sundiol and 1 kg of ethylene carbonate
A 2.4 kg reactor was charged. 65 ° C heat on jacket
Heat the reaction tank by circulating the medium, and stir
Was replaced with nitrogen three times. 250 ° C jacket temperature
And adjust the pressure so that the temperature inside the reaction tank becomes 150 ° C.
It was adjusted. A condenser is installed at the outlet of the rectification tower to distill
After collecting the collected liquid in the distillate tank,
I returned. When the temperature in the reactor reaches 150 ° C,
The tank pressure was 10 kPa and the distillate tank was 5.5
 A distillate was sent at 1 / hr. In that state,
And then 1.5 l / hr from the distillate tank to 3
hr, and 1.2 l / hr for a portion of the distillate for 7 hr.
The reaction was carried out while extracting into the extraction tank. Extractor
The liquid composition in the ink was analyzed by gas chromatography.
Roller, ethylene glycol 80% by weight, ethylene car
It contained 17% by weight of bonate. Switch piping,
The reactor was directly connected to the condenser at the outlet of the rectification column. reaction
The reaction was performed while the pressure in the tank was gradually reduced to 0.5 kPa.
Keep the temperature of the jacket so that the temperature in the bath does not exceed 170 ° C.
The reaction was further performed for 2 hours while adjusting the temperature to 15.1 kg.
Was obtained. Distilled liquid into gas
Analysis by chromatography showed that ethylene
24 wt%, 1,5-pentanediol 33%
Wt%, 27 wt% of 1,6-hexanediol,
It contained 7% by weight of lenglycol. Poly obtained
Carbonate diol (C _FiveC₆PCDL) Number average molecular weight
2,000 and C_Five・ C₆Components contained in PCDL
(C) The amount of (ether unit) is 0.8 mol%.
Was.

The OH value and molecular weight shown in the present invention were measured as follows. Acetic anhydride (5 g) was made up with pyridine (20 ml) to prepare an acetylation reagent. 0.5-1.0 g of the sample is precisely weighed in a 50 ml eggplant flask. After adding 2 ml of the acetylating reagent and 4 ml of toluene with a whole pipette, a condenser is attached, and the mixture is heated with stirring at 100 ° C. for 1 hour. 1 ml of distilled water is added with a whole pipette, and the mixture is further heated and stirred for 10 minutes. After cooling for 2 to 3 minutes, 5 ml of ethanol is added, and 2 to 3 drops of phenolphthalein are added as an indicator, followed by titration with 0.5 mol / l ethanolic potassium hydroxide. Acetylation reagent 2m
l, 4 ml of toluene and 1 ml of distilled water are placed in a 50 ml eggplant flask, heated and stirred for 10 minutes, and then titrated similarly (blank test). Based on this result, O
The H value was calculated.

Equation (1) OH value (mg-KOH / g) = ｛(BA) × 28.5
× f1｝ / C A: titer of sample (ml) B: titer of blank test (ml) C: sample weight (g) f1: factor of titrant

The polymer terminals in the Examples and Comparative Examples are
^{By 13} C-NMR measurement. Substantially all were hydroxyl groups. Further, the acid value in the polymer was measured by titration with KOH, and it was found that all of the polymers of the practical examples and the comparative examples were 0.01 or less. Therefore, the number average molecular weight of the obtained polymer is obtained by the following equation (2).

Formula (2) Number average molecular weight = 2 / (OH value × 10 ⁻³ /56.11)

The amount of the component (C) (ether unit) in the present invention indicates the following. An ether bond is generated when ethylene oxide generated by a decarboxylation reaction of ethylene carbonate bonds with diol used as a raw material or ethylene glycol generated by a polymerization reaction.
The amount of the ether bond contained in PCDL is represented as the amount of an ether unit (the amount of the component (C)). The ether unit shown in the present invention was measured as follows. 100ml
Take 1 g of the sample in an eggplant flask of
g and 4 g of potassium hydroxide, and reacted at 100 ° C. for 1 hour. After cooling to room temperature, 2-3 drops of phenolphthalein are added to the indicator and neutralized with hydrochloric acid. 1 hour in refrigerator
After cooling, the precipitated salts were removed by filtration and analyzed by gas chromatography. Analysis is DB as a column
Using a gas chromatography GC-14B (manufactured by Shimadzu Corporation) equipped with a WAX (manufactured by J & W), using diethylene glycol diethyl ester as an internal standard, and using a FID as a detector
Went as. The column temperature rise profile was 60
After holding at 5 ° C. for 5 minutes, the temperature was raised to 250 ° C. at 10 ° C./min. In the composition analysis, the molar ratio of the diol used in the polymerization was expressed based on the obtained results. The component (C) (amount of ether unit) was determined by the following equation (3) based on the result.

Formula (3) Component (C) (ether unit) amount (mol%) = (D /
E) × 100 D: mole number of ether E: mole number of diol and ether

(Production of emulsion) 500 parts of C ₅ C ₆ PCDL obtained by the above method, 126 parts of HDI, 58.5 parts of dimethylolpropionic acid (DMPA) whose carboxyl group was neutralized with triethylamine, 1027 of methyl ethyl ketone (MEK) The part was placed in a reactor having a reflux condenser, a thermometer and a stirrer, and a urethanization reaction was carried out at 80 ° C. for 4 hours to obtain an NCO-terminated prepolymer solution. The prepolymer solution was dissolved in 7 parts of sodium dodecylbenzenesulfonate (Na-DBS) and gradually added to 1578 parts of distilled water set to a temperature of 30 ° C. while stirring to prepare an emulsion of the prepolymer solution. did. Thereafter, 106.5 parts of a 20% aqueous solution of isophoronediamine (IPDA) as a chain extender was added over 30 minutes,
The temperature was raised to 40 ° C. and the reaction was carried out for 1 hour to increase the molecular weight. Thereafter, MEK was removed under reduced pressure to obtain a solid content of 3%.
A 0% polyurethane emulsion was obtained. After allowing the emulsion to stand for 3 days, a film is formed on a glass plate (at room temperature for 2 days).
After film formation for 4 hours, heat treatment at 120 ° C. for 20 minutes), a sample film having a thickness of 100 μm, a width of 10 mm, and a length of 60 mm obtained by using a sample film (under a measurement atmosphere at −20 ° C.) and olein The strength retention when immersed in an acid was measured. Table 1 shows the obtained results.

(Measurement conditions of film) Measuring machine: Tensilon tensile tester Orien Lac RTA-k Co., Ltd. Grasping length: 30 mm Tension speed: 300 mm / min

(Oleic Acid Resistance of Film) The above film sample was immersed in oleic acid at room temperature for 2 days, and the strength retention (%) of the film was determined.

Example 2 (Production of polycarbonate diol) A reaction was carried out using the apparatus used in Example 1. 13.0-butanediol was added to 13.0
kg, 1.3 kg of 1,6-hexanediol and 13.7 kg of ethylene carbonate were charged into a reaction vessel. The reaction vessel was heated by circulating a heating medium at 65 ° C. through the jacket, and the inside of the reaction vessel was replaced with nitrogen three times while stirring. The temperature of the jacket was raised to 230 ° C., and the pressure was adjusted so that the temperature inside the reaction tank became 150 ° C. A condenser is attached to the outlet of the rectification tower, and the distillate is collected in the distillate tank,
The whole amount was returned from the top of the rectification column. When the temperature in the reactor is 170
When the temperature reached ° C, the pressure in the reaction tank was 6 kPa, and the distillate was sent to the distillate tank at 5.0 l / hr. In this state, after performing the reaction for 1 hour, 1.
1 l at 5 l / hr, 3 h at 1.0 l / hr
The reaction was carried out while a part of the distillate was withdrawn at 0.7 l / hr for 3 hr and withdrawn into a tank. When the liquid composition in the extraction tank was analyzed by gas chromatography, it was found to contain 70% by weight of ethylene glycol and 26% by weight of ethylene carbonate. The piping was switched to connect directly from the reactor to the condenser at the outlet of the rectification column. While gradually reducing the pressure in the reaction tank to 0.6 kPa, while adjusting the temperature of the jacket so that the temperature in the reaction tank does not exceed 190 ° C., the reaction was further performed for 1.5 hr to perform 13.1 kg of P.
CDL was obtained. When the distillate was analyzed by gas chromatography, it was found that ethylene carbonate contained 32% by weight,
57% by weight of 1,4-butanediol, 3% by weight of 1,6-hexanediol, 7% by weight of ethylene glycol
Was included. The obtained polycarbonate diol (C
₄ C ₆ PCDL) has a number average molecular weight of 2,000 and C ₄
Component (C) (amount of ether unit) contained in C ₆ PCDL was 3.8 mol%.

(Emulsion Production Method) Using the C ₄ · C ₆ PCDL obtained by the above production method, a polyurethane emulsion was produced in exactly the same manner as in Example 1, a sample film was produced, and the same as in Example 1. Was evaluated. Table 1 shows the obtained results.

Example 3 In Example 1, the temperature in the reaction vessel at the start was set to 15
Change the temperature from 0 ° C to 170 ° C, switch the piping, and raise the temperature of the reaction tank from 170 ° C to 19 ° C when reacting without passing through the rectification column.
Except that the temperature was changed to 0 ° C., the same operation as in Example 1 was controlled so that the number average molecular weight became 2000. The obtained C ₅ C ₆ PCDL has a number average molecular weight of 2,000.
And the component (C) (amount of ether unit) contained in C ₅ C ₆ PCDL was 2.5 mol%.

Using this C ₅ C ₆ PCDL, a polyurethane emulsion was produced in the same manner as in Example 1, a sample film was produced, and the same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

Comparative Example 1 In Example 1, except that the temperature of the first and second half reactors was changed from 150 ° C. to 180 ° C. and from 170 ° C. to 210 ° C., respectively, while controlling the number average molecular weight to be 2,000. The same operation as in Example 1 was performed. The obtained C ₅ · C ₆ PCDL has a number average molecular weight of 2,000,
The component (C) (amount of ether unit) contained in C ₅ C ₆ PCDL was 9.7 mol%.

Using this C ₅ C ₆ PCDL, a polyurethane emulsion was produced in the same manner as in Example 1, a sample film was produced, and the same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

Comparative Example 2 (Production of polycarbonate diol) 472 parts (4.0 mol) of 1,6-hexanediol and 1,4-butanediol 360 were placed in a reactor equipped with a stirrer, a thermometer and a fractionating tower. (4.0 mol) and 1.84 parts (0.08 mol) of metallic sodium were added with stirring at 70-80 ° C. After the sodium had completely reacted, 472 parts (8.0 parts)
Mol) of diethyl carbonate. As the reaction temperature was raised to 59-100 ° C, ethanol began to distill. The temperature was gradually increased to 160 ° C. in about 6 hours. During this time, ethanol containing about 10% diethyl carbonate was distilled off. Thereafter, the pressure of the reactor was further increased by 10
The reaction was carried out at 200 ° C. for 4 hours under strong stirring. The resulting polymer was dissolved in dichloromethane after cooling, neutralized with dilute acid, washed repeatedly with water several times, dehydrated with anhydrous sodium sulfate, and then distilled off the solvent.
Further, it was dried at 140C for several hours at 2-3 mmHg.
Obtained polycarbonate diol (C ₄ C ₆ PCDL)
Was 2000, and the component (C) (amount of ether unit) in C ₄ C ₆ PCDL was 0 mol%.

(Emulsion manufacturing method) This C ₄ C ₆ PCDL
Was used to produce a polyurethane emulsion in the same manner as in Example 1, a sample film was produced, and the same evaluation as in Example 1 was performed. Table 1 shows the obtained results.

(Table 1) Example Comparative example (1) (2) (3) (1) (2) Physical properties of film Breaking strength at −20 ° C. 340 380 370 370 380 (kg / cm ² ) Breaking Elongation 500 500 520 570 410 (%) 100% Modulus 38 39 35 29 55 (kg / cm ² ) Oleic acid resistance 80 85 75 48 85 (Strength retention%)

Example 4 Using the C ₅ C ₆ PCDL of Example 3, HDI was changed to IPDI in the emulsion production of Example 1, and a 20% aqueous solution of IPDA was changed to a simple aqueous solution as a chain extender. A polyurethane emulsion was produced in the same manner as in Example 1. Artificial leather was manufactured using this polyurethane emulsion.

By the direct spinning method, 0.1 denier (2
A 50 d / 2500 f) PET ultrafine fiber was manufactured and cut into a length of 5 mm. It was dispersed in water to obtain a slurry for papermaking. The slurry was made into a non-woven web having a basis weight of 80 g / m ² , and a 75-denier / 36-filament P
The nonwoven web was laminated on both sides of a plain woven fabric made of ET fiber with a basis weight of 50 g / m ² , and three-dimensionally entangled and integrated by high-speed water jet. The high-speed water flow was injected from a straight flow injection nozzle having a hole diameter of 0.1 mm at a pressure of 30 kg / cm ² . This operation was performed from both the front and back surfaces of the laminated sheet, and the basis weight was 210 g / m ² , the thickness was 0.95 mm, and the apparent density was 0.
A 22 g / m ² sheet was produced. This sheet was formed using emery paper No. 240 at a paper speed of 7
The surface was puffed at 00 m / min to a thickness of 0.9 mm. It has a viscosity of 6.0 centipoise and a saponification degree of 86-8.
The mixture obtained by mixing the 18% aqueous solution of polyvinyl alcohol (PVA) with 9 mol% and the polyurethane emulsion obtained in Example 1 and having a PVA concentration of 6% and a polyurethane emulsion solid concentration of 7% was mixed with the non-flushed hair in the above step. The woven sheet was immersed and squeezed with a mangle to adjust the impregnation amount of the mixture to 2.5 times that of the sheet, and then heated and dried by heating at 130 ° C. for 4 minutes using a pinch tenter type hot air dryer.
When the sheet-like composite is observed with a microscope, the surface of the nap is P
VA adhered and no piloerection was observed. Next, the sheet-like composite is put into hot water to extract PVA,
After being thoroughly washed with water, it was dried to obtain a suede-like artificial leather.
The low-temperature flexibility and oleic acid resistance of this suede-like artificial leather were evaluated. The results are shown in Table 2.

Comparative Example 3 Using C ₅ C ₆ PCDL of Comparative Example 1, a polyurethane emulsion was produced in the same manner as in Example 4, and an artificial leather was produced using this polyurethane emulsion. Table 2 shows the evaluation results.

Comparative Example 4 Using the C ₄ C ₆ PCDL of Comparative Example 2, a polyurethane emulsion was produced in the same manner as in Example 4, and an artificial leather was produced using this polyurethane emulsion. Table 2 shows the evaluation results.

(Table 2) Example 4 Comparative Example 3 Comparative Example 4 Low Temperature Flexibility ◎ ◎ △ Oleic Acid Resistance ◎ △ ◎

[0057]

As described above, the polyurethane emulsion of the present invention is suitable for producing synthetic leather and the like having excellent low-temperature flexibility, low-temperature flexibility and sweat resistance.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus used for producing a polycarbonate diol of an example.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F055 AA02 BA11 EA04 EA11 EA22 EA25 EA28 EA36 FA07 FA20 GA03 4J034 BA08 CA04 CA15 CA22 CB03 CB04 CB07 CB08 CC03 CC12 CC23 CC26 CC34 CC45 CC52 CC61 CC62 CC65 CC01 CE01 DB01 HA07 HC03 HC12 HC13 HC17 HC22 HC46 HC52 HC61 HC64 HC65 HC67 HC71 HC73 JA03 JA13 JA30 JA42 QA07 QC05 RA03

Claims (2)

[Claims] 1. A urethane prepolymer comprising a compound having (1) an organic diisocyanate, (2) a polycarbonate diol, (3) a compound having one hydrophilic center and at least two isocyanate-reactive centers, and a chain extender. In a polyurethane emulsion consisting of the reaction product of
The (2) polycarbonate diol is represented by the following (A):
Polyurethane emulsion comprising (B) and (C) (Where m and n are integers of 4 to 6, and m = n or
m ≠ n, R ′ is an ethylene group, R ″ is an alkylene group having 2 to 6 carbon atoms, and the ratio of (A) to (B) is 9: 1 to 1:
9 (molar ratio), wherein (C) is contained in an amount of 0.2 to 7 mol% based on the total amount of (A), (B) and (C). 2. Synthetic leather and artificial leather produced using the polyurethane emulsion according to claim 1.