JP2996797B2 - Manufacturing method of leather-like sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing artificial leather having a soft natural leather-like delicate texture and excellent in bending durability, deterioration resistance and practicality.

[0002]

2. Description of the Related Art In recent years, artificial leather has been widely used as a substitute for natural leather. As a substitute for natural leather with silver, a product developed by forming a porous layer of polyurethane resin etc. on the surface of the base layer by impregnating with a conventional polyurethane resin solution etc. and applying a polyurethane resin paint on the surface was developed Have been. In this case, softness and texture are improved by reducing the thickness of the polyurethane resin porous layer and decreasing the density. However, softness, resilience like leather, and delicate texture are not enough.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide a leather-like sheet having excellent softness and a delicate grain like natural leather.

[0004]

Means for Solving the Problems The present invention relates to a heat treatment of a web containing heat-shrinkable fibers to obtain a non-woven fabric having an area shrinkage of at least 30%, and hot-pressing the non-woven fabric to obtain an apparent density of 0.1%. 2 to 0.40 g / cm ³ of a fibrous base material, and then impregnating the fibrous base material with a polyurethane elastic solution, the surface layer of which is a composite of both the fibers constituting the fibrous base material and the polyurethane elastic material. (A) an aliphatic and / or alicyclic diisocyanate, (b) a polymer diol having a molecular weight of 600 to 4000, (c) an aliphatic diamine and / or an oil. 100% elongation stress obtained from cyclic diamine 5 to 40 kg / cm
² , a polyurethane elastomer [A] having a breaking elongation of 600% or more and b) a ketone or ester having a boiling point of 60 to 150 ° C;
A paint consisting of a solvent selected from the group consisting of ethers, cyclic ethers, alcohols and hydrocarbon solvents, alone or in combination, or a solvent in which these solvents are mixed with an amide-based solvent in a proportion of 20% or less, at least in solid content. 2 to 50 g
/ M ² coated and dried to form a first layer, and the first layer has a 100% elongation stress of 40 to 40%.
A leather-like sheet formed by applying a coating consisting of a 150 kg / cm ² polyurethane elastomer [B] solution at a solid content of 1 to 50 g / m 2 to form a second layer. A method for producing a leather-like sheet material, wherein a coating material comprising a solution of a polyurethane elastomer [C] having an extension stress of 100 to 400 kg / cm ² is formed at a solid content of 1 to 10 g / m ² .

As the heat-shrinkable fiber constituting the fibrous base material of the present invention, a synthetic fiber which shrinks in hot water or hot air can be used. Preferably, a heat-shrinkable fiber obtained by spinning a fiber-forming polymer containing polyethylene terephthalate as a main component and then drawing it at a low magnification in warm water and having a shrinkage of 40% or more in 70 ° C warm water. is there. In order to achieve the object of the present invention, the area shrinkage of the nonwoven fabric needs to be at least 30%, and in order to satisfy this, it is necessary to optimize the shrinkage and the mixing ratio of the heat-shrinkable fiber.
For example, in the case of the above-mentioned polyester heat-shrinkable fiber having a shrinkage ratio of 40% or more in hot water at 70 ° C., this fiber is used alone or a mixture of other non-shrinkable fibers is used.

A known method can be used to produce a nonwoven fabric from the obtained fibers. However, a method in which fibers are applied to a card, a web is formed with a random webber or a cross wrapper, and then needle punching is performed is useful.

The web thus prepared is treated in warm water or hot air to reduce the area shrinkage by 30% or more, preferably 40% or more.
% Or more. When the area shrinkage ratio is less than 30%, the obtained sheet-like material is unpreferably a sharp wrinkle and a paper-like hand.

Next, the apparent density is 0.2 to 0.40 g / cm.
^The non-woven fabric is hot-pressed so as to obtain ³ . Set the apparent density to 0.
In order to obtain 2 to 0.40 g / cm ³ , the temperature at the time of pressing,
Adjust pressure and processing time. The temperature for hot pressing is
When the treatment is performed by dry heat, the treatment is performed at a temperature lower than the softening temperature of the fiber and higher than a temperature lower by 30 ° C. than the softening temperature. If the temperature is higher than the softening temperature, the surface layer is fused, and if the temperature is lower than the softening temperature by 30 ° C. or more, the effect of increasing the density of the nonwoven fabric is small and the effect of holding down the fuzz is small.

[0009] Preferably, about 50 to about 50% by weight of the nonwoven fabric
Using a metal plate or a roll press machine having a smooth surface heated in a state of containing 200% water, hot non-woven fabric having a fluffy surface is formed by hot pressing with wet heat.
When the apparent density is less than 0.2 g / cm ^3, wrinkles are large, and when the apparent density is more than 0.40 g / cm ³ , the feeling becomes hard, which is not preferable.

The fibrous base material thus obtained is impregnated with a polyurethane elastic solution and coagulated into a porous form by a wet or dry coagulation method. When squeezing excess treatment liquid by impregnating the body solution or dispersion, the surface layer becomes not only the layer of the impregnated polyurethane elastic solution but also the impregnated polyurethane elastic solution and the fiber of the fibrous base material. Need to be present in a complex with each other.

The polyurethane elastic material used for impregnation is 100
Polyurethane having a% elongation stress of 20 to 120 kg / cm ² can be used. Generally, diisocyanates are aromatic, aliphatic, alicyclic diisocyanates, and polymer diols are polyesters, polyethers, and polycarbonates. It is obtained by reacting a chain extender with a diol or diamine having a molecular weight of 200 or less. In a preferred embodiment of the present invention, the content of the polyether-based or polycarbonate-based polymer diol is preferably 50% or more of the total weight of the polymer diol in order to enhance the resistance to deterioration during wearing.

Next, an organic solvent which does not destroy the porosity of the polyurethane elastic body formed on the surface layer of the impregnated base material;
(A) aliphatic and / or alicyclic diisocyanate,
(B) a polymer diol having a molecular weight of 600 to 4000,
(C) 100% elongation stress obtained from aliphatic diamine and / or alicyclic diamine 5 to 40 kg / cm ² , elongation at break 6
A coating composed of a solution of the polyurethane elastomer [A] of 00% or more is applied in a solid content of ² to 50 g / m ² . Here, the reason for applying the solution of the polyurethane elastomer having such special physical properties is to prevent interfacial destruction in the composite surface layer formed from the fibers of the fibrous base material and the porous polyurethane elastic material. That is, when the composite surface layer is repeatedly subjected to bending deformation in practical use, it undergoes elongation or compression deformation, and at that time, breakage occurs at the interface between the fiber and the polyurethane elastic body, and cracks, adhesion of dirt, soaking in rainwater, etc. Quality defects occur. This is due to the large modulus difference between the fibers of the fibrous base material and the polyurethane elastic porous material. In order to prevent the destruction of the interface between the fiber and the urethane porous material due to such deformation, it is effective to use a paint that follows this deformation and does not cause breakage. For this reason, the polymer used in the coating material has a relatively low modulus of 100% elongation stress of 5 to 40 kg / cm ² and a breaking elongation of 600% or more in an elongation test, preferably 700 at 10 to 40 kg / cm ² .
~ 900% is required. If the 100% elongation stress is higher than the above and the cutting elongation is lower than the above, it is difficult to prevent the destruction of the interface.

[0013] The paint to be applied is the surface appearance of the final product,
It should not impair smoothness or the like. For this purpose, it is necessary to use a solvent for the paint which does not destroy or damage the porosity of the polyurethane elastic body. As those satisfying these purposes, ketones such as acetone, methyl ethyl ketone, diethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and butyl acetate, cyclic ethers such as tetrahydrofuran and dioxane, ethyl alcohol, propyl alcohol, butyl Alcohols such as alcohol, benzene,
It consists of a single or mixed solvent of hydrocarbon solvents such as toluene, xylene and cyclohexane, and has a boiling point of 60 to 150 ° C.
Or a solvent in which an amide solvent such as dimethylformamide or dimethylacetamide is mixed at a ratio of 20% or less, and these can be selected and used.

Polyurethane elastomers [A] dissolved in these solvents and having the above-mentioned properties include tetrabutylene diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate, 3,3,5 trimethyl,
Aliphatic and / or alicyclic diisocyanates (a) such as 5-isocyanate, methyl cyclohexyl isocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and polyoxyethylene glycol, polypropylene glycol, polytetramethylene glycol having a molecular weight of 600 to 4000; Ether-based polymer diols,
Polycarbonate diols such as polytetramethylene carbonate diol and polyhexamethylene carbonate diol; and polymer diols (b) such as ester polymer diols such as polyethylene adipate, polybutylene adipate and polyhexamethylene adipate; and propylene diamine, hexamethylene diamine; Cyclohexyldiamine, 3,3,5 trimethyl
It is obtained by reacting an aliphatic and / or alicyclic diamine (c) such as 5-aminomethyl-cyclohexylamine and 4,4'diaminodicyclohexylmethane.

In order to adjust the 100% elongation stress in the range of 5 to 40 kg / cm ² , the molar ratio of the isocyanate component and the (diamine + polymer diol) component to be reacted is 0.9.
It can be adjusted by changing the ratio between the diamine and the polymer diol within the range of about 8 to 1.02. In order to make the breaking elongation of the polyurethane elastomer [A] 600% or more, it is necessary to sufficiently increase the degree of polymerization of the polyurethane elastomer during the reaction.
Care must be taken to match the chemical equivalents of the reaction components and to sufficiently control the moisture in the raw materials.

Regarding the composition of the polyurethane elastomer [A], in a preferred embodiment of the present invention, the polymer glycol (b) is prepared by using an aliphatic carbonate diol or a polyalkylene ether diol alone or in a mixture of at least 50% by weight of the polymer glycol. It is possible to obtain a sheet-like material excellent in deterioration resistance by
Further, by using polyoxyethylene glycol as the polyalkylene ether diol, it is possible to improve moisture permeability.

Dyes, pigments, and the like may be added as a colorant to the coating composed of the solution of the polyurethane elastomer [A]. However, when a large amount of pigment or the like is added, the modulus of the coating film increases, the elongation at break decreases, and the object of the present invention cannot be achieved. Therefore, the amount added depends on the modulus of the polyurethane elastomer, but must be in a range that does not reduce these properties.

The method of applying a coating consisting of a solution of the polyurethane elastomer [A] includes a gravure roll coater,
Known methods such as a reverse roll coater and a knife coater can be used, but if the coating amount is less than 2 g / m ² , the effect of the present invention is small. If the coating amount exceeds 50 g / m ² , the hand becomes hard and the decrease in moisture permeability is large. Not preferred.

Next, the 100% elongation stress is 40 to 150 kg /
A coating consisting of a solution of the polyurethane elastomer [B] of 1 cm ² is applied at a solid content of 1 to 50 g / m ² . As the polyurethane elastomer [B] having a 100% elongation stress of 40 to 150 kg / cm ² , a soft solvent type of the above-described polyurethane elastomer [A] having a 100% elongation stress adjusted to a specified range can be used, and diphenylmethane diisocyanate is used as an isocyanate. Aromatic diisocyanates such as naphthalene diisocyanate, tolylene diisocyanate, xylylene diisocyanate and ether-based polymer diols such as polyoxyethylene glycol, polypropylene glycol and polytetramethylene glycol having a molecular weight of 600 to 4000, polytetramethylene carbonate diol, polyhexa Carbonate-based polymer diols such as methylene carbonate diol, polyethylene adipate, polybutylene adipate, poly Kisa polymer diol and ethylene glycol, such as ester-based polymer diol, such as adipate, 1,4-butanediol, a diol such as 1,6-hexanediol, propylene diamine, hexamethylene diamine, cyclohexyl diamine, 3,3,5
Trimethyl-5-aminomethyl-cyclohexylamine,
An aromatic polyurethane obtained by reacting with a chain extender such as an aliphatic and / or alicyclic diamine such as 4,4'-diaminodicyclohexylmethane can be used.

In order to obtain a polyurethane elastomer [B] having a 100% elongation stress of 40 to 150 kg / cm ² , the molar ratio of the isocyanate component and the (polymer diol + chain extender) component is adjusted to the range of 0.98 to 1.02. Shi (chain extender /
It can be adjusted by changing the molar ratio of the polymer diol).

When the aromatic polyurethane is used as the solvent for the paint, some amide solvents such as dimethylformamide and dimethylacetamide may be used to maintain the stability of the solution.

The paint may contain an appropriate amount of a dye or a pigment as a colorant. The limit of the amount added depends on the modulus of the polyurethane elastomer used. Must be kept within a range that does not impair. Polyurethane elastomer [B]
If the 100% elongation stress is less than 40 kg / cm ² , the modulus is too low and the tackiness is too strong, the friction is high, and the abrasion resistance is poor. If it exceeds 150 kg / cm ² , the modulus is high and the hand is hard. However, the flexibility at low temperatures becomes inferior, which is not preferable. If the coating amount is less than 1 g / m ² , the thickness of the coating film is too small and the wear resistance and the bending resistance are not sufficient. 50g / m
^If it exceeds ² , the texture becomes hard and the texture becomes worse, which is not preferable. Preferably it is in the range of 3 to ²⁰ g / m ² .

Finally, a coating composed of a solution of the polyurethane elastomer [C] is applied to the outermost surface in an amount of 1 to 20 g / m ² . The polyurethane elastomer [C] has a 10% elongation stress of 100 to 400 kg / cm ² , preferably 150%.
It is those of ~350kg / cm ^2. Specific examples of the polyurethane elastomer [C] include a soft solvent type of the above-mentioned polyurethane elastomer [A] in which a 10% elongation stress is adjusted to a specified range. In addition, diphenylmethane diisocyanate, naphthalene diisocyanate, tolylene diisocyanate, and xylene Aromatic diisocyanates such as diisocyanate and ether-based polymer diols having a molecular weight of 600 to 4000, such as polyoxyethylene glycol, polypropylene glycol, and polytetramethylene glycol; and carbonate-based polymer diols such as polytetramethylene carbonate diol and polyhexamethylene carbonate diol. , Polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, etc. Polymer diol and ethylene glycol, such as ether-based polymer diol, 1,4-butane diol, diols such as 1,6-hexanediol, propylene diamine, hexamethylene diamine, cyclohexyl diamine, 3,
An aromatic polyurethane obtained by reacting with a chain extender such as an aliphatic and / or alicyclic diamine such as 3,5 trimethyl-5 aminomethyl cyclohexylamine and 4,4 'diaminodicyclohexylmethane can be used.

To obtain a polyurethane elastomer [C] having a 10% elongation stress of 100 to 400 kg / cm ² , the molar ratio between the isocyanate component and the (polymer diol + chain extender) component is adjusted to the range of 0.98 to 1.02. Shi (chain extender /
(Polymer diol) can be adjusted by increasing the molar ratio. Among these polyurethane elastomers, those having a yield point of 5 to 25% are most preferred. If the 100% elongation stress is less than 100 kg / cm ² , the modulus difference between the first layer and the second layer is small, and it is difficult to obtain a delicate grain. If it exceeds 400 kg / cm ² , the elongation is reduced and cracks are liable to occur. Not preferred. The coating amount is now flexing resistance especially low-temperature flexing resistance becomes hard, high modulus coating layer is too thick texture and exceeds 20 g / m ² poor, the polyurethane elastomer [B] is less than 1 g / m ² The properties remain, the coefficient of friction is large, the slip is poor, and the workability such as sewing of the sewing machine becomes poor.

A dye, a pigment, a gloss adjusting pigment, and the like may be added in an appropriate amount to a coating material comprising a solution of the polyurethane elastomer [C]. In a preferred embodiment of the present invention, at least 50% by weight of the polymer diol of the polyurethane elastomers [B] and [C] is polyoxyethylene glycol. By using this, a leather-like sheet having high moisture permeability can be obtained. Obtainable.

[0026]

The leather-like sheet obtained by the production method of the present invention has a soft natural leather-like delicate texture,
Moreover, it is an artificial leather excellent in bending durability and deterioration resistance and excellent in practicality.

Hereinafter, the present invention will be described in detail with reference to examples. Parts shown below are parts by weight unless otherwise specified.
The characteristic values of the present invention were measured by the following methods.

10%, 100% elongation stress A polyurethane resin coating solution was cast on a glass plate with a weir and dried to prepare a polyurethane resin film having a thickness of about 0.1 to 0.15 mm, which was obtained according to JIS. K-6301-3
A No. 2 type dumbbell test piece is prepared by a vulcanized rubber tensile test method. This was conditioned in a room at 23 ± 2 ° C. and 60 ± 5% RH, and then pulled at a constant speed of 20% with a constant-speed tensile tester.
It is measured at 0 mm / min and is shown as a value obtained by dividing the load at 10% and 100% elongation by the measured cross-sectional area from the thickness of the test piece.

Apparent density The nonwoven fabric is cut into a size of 10 cm (length) × 10 cm (width) and its weight is measured. This is divided by the total area and converted to the weight per 1 cm ² . Next, the thickness of the test piece is measured under a load of 150 g / cm ² , and the above-mentioned weight is divided by the thickness.

[0030]

Example 1 Production of fibrous base material Polyethylene terephthalate fiber (single fiber fineness: 2 denier, length: 51 mm) having a shrinkage of 50% in hot water at 70 ° C. and extensibility of 10% when heat-treated at 180 ° C. Was mixed at a ratio of 80/20 to produce a web of 240 g / m ² using a card and a cross wrapper.
This web is passed through a needle locker room and 800 /
Needle punching of cm ² was performed, followed by immersion in hot water at 70 ° C. for 5 minutes to shrink to 62% of the original area. This was treated at 130 ° C. while applying a pressure of 0.12 kg / cm ² using a cylinder belt press, and the weight was 390 g / m 2.
^2. A non-woven fabric (fibrous base material) having a thickness of 1.3 mm and an apparent density of 0.30 g / cm ³ was obtained.

Production of polyurethane elastomer 585 parts of polybutylene adipate (molecular weight 170
9) 311 parts of polytetramethylene ether glycol (molecular weight 1493), 126 parts of 2,2-bis [4-
(Β-hydroxyethoxy) phenyl] propane, 67
A mixture of 0 parts of diphenylmethane-4,4'-diisocyanate, 0.05 parts of triethylenediamine and 411 parts of methyl ethyl ketone was placed in a reactor equipped with a stirrer.
The reaction was carried out at 0 ° C. for 80 minutes to obtain a polyurethane prepolymer. The resulting prepolymer was then charged with 156 parts of 1,
4-Butanediol and 3.2 parts of triethylenediamine were added, and the mixture was reacted at 80 ° C. for 4 hours while 6789 parts of methyl ethyl ketone was gradually dropped. The polyurethane solution thus obtained was in the form of a slurry and had a concentration of 20%.

Production of Polyurethane-impregnated Nonwoven Fabric After 100 parts of the above polyurethane solution were added with 5 parts of a surfactant obtained by reacting polypropylene oxide and polyoxyethylene oxide with diphenylmethane-4,4'-diisocyanate, 30 parts of water was added with stirring. Was added to obtain a W / O emulsion.

The above-mentioned fibrous base material is immersed in the obtained emulsion, and excess polyurethane is scraped off with a squeeze doctor so that both surfaces of the above-mentioned polyurethane and fiber are present.
After immersion in water at 0 ° C. for 3 minutes, the mixture was treated in an atmosphere of 60 ° C. and 50% RH for 10 minutes to evaporate the solvent.
After drying at 0 ° C. for 10 minutes, a polyurethane-impregnated nonwoven fabric was obtained.

Synthesis of Polyurethane Elastomer [A] 750 parts of a 1: 1 mixture of polytetramethylene glycol having a molecular weight of 2,920 and polyhexamethylene carbonate diol having a molecular weight of 2,800, and 210 parts of dicyclohexylmethane diisocyanate were placed in a reactor equipped with a stirrer and purged with nitrogen. After reacting at 90 ° C. for 80 minutes, 2100 parts of a solvent mixed at a ratio of methyl ethyl ketone (MEK) / toluene (TOL) / dimethylformamide (DMF) = 50/42/8 was added, dissolved and cooled to 40 ° C. Next, a solution obtained by dissolving 39 parts of 1,2 propylenediamine in 90 parts of the same mixed solvent was added little by little, and a chain extension reaction was carried out for 6 hours. Then, 3.5 parts of dibutylamine was added to stop the reaction. Was obtained. After diluting the obtained polymer solution to 10% by weight with DMF,
It was cast on a glass plate with a weir, roughly dried at 50 ° C. for 12 hours, and vacuum dried at 80 ° C. for 2 hours to prepare a polyurethane film. The 100% elongation stress measured on this film was 21 kg / cm ² and the elongation at break was 820%.

Production of Leather-Like Sheet Material The synthesized polyurethane elastomer solution [A] was treated with MEK
After diluting to a concentration of 13% using a solvent mixed at a ratio of / TOL / DMF = 50/42/8, the solution was applied to the surface of the polyurethane-impregnated nonwoven fabric three times with an 80-mesh gravure coater three times. To prepare a sheet coated with a 12 g / m ² polyurethane elastomer [A] solution.

On the other hand, when the polyurethane-impregnated nonwoven fabric to which the solution of the polyurethane elastomer [A] was not applied was repeatedly bent, cracks occurred at the interface between the fiber and the polyurethane elastic body. It was useful as a base material. The moisture permeability is 6.
It was 5 mg / cm ² · hr.

[0037]

Example 2 Synthesis of polyurethane elastomer [B] Polytetramethylene glycol 585 having a molecular weight of 2010
Parts and 330 parts of diphenylmethane diisocyanate were placed in a reactor equipped with a stirrer and purged with nitrogen, and reacted at 80 ° C. for 60 minutes. Then, 3640 parts of a mixed solvent of MEK / DMF = 50/50 was poured and dissolved while cooling. Then, 0.2 parts of dibutyltin dilaurate was added, and 90 parts of 1,4 butanediol was mixed with the same mixed solvent as above. 2. Dibutylamine was added to the solution, and the mixture was added for 1 hour and reacted for 6 hours.
The reaction was stopped by adding 5 parts. The resulting polymer solution had a 750 poise at 30 ° C. and a 100% elongation stress of 110 kg /
It was cm ^2.

Next, a toner containing carbon black was added to this polymer solution in an amount of 5% by weight in terms of carbon black, and diluted with a mixed solvent of MEK / DMF = 70/30 to obtain a coating having a concentration of 11%. This was converted to a solid content with a 110 mesh gravure coater at 15 g /
It was applied as a m ^2. Next, a leather-like sheet was prepared by embossing at 150 ° C. using an embossing roll molded from natural leather. The resulting sheet was soft and excellent as a shoe material.

[0039]

Example 3 Synthesis of Polyurethane Elastomer [C] A mixture of 443 parts of polytetramethylene glycol having a molecular weight of 795 and 370 parts of 3,3,5 trimethyl, 5 isocyanatomethylcyclohexyl isocyanate was placed in a reactor equipped with a nitrogen-substituted stirrer and charged at 90 ° C. After reacting for
Mixed solvent 3 of EK / THF / DMF = 20/40/40
After adding 260 parts and dissolving while cooling, and cooling to 40 ° C., a solution obtained by dissolving 184 parts of 3,3,5 trimethyl, 5aminomethylcyclohexylamine in 735 parts of the mixed solvent was poured, and then added at 40 to 50 ° C. For 8 hours, and finally 3.5 parts of di-n-butylamine was added to terminate the reaction. The resulting polymer solution had a 980 poise at 30 ° C. and a 10% elongation stress of 320 kg / cm ² .

Preparation of Leather-Like Sheet Material A coating material was prepared by diluting the polyurethane elastomer solution [C] to 10% with the same mixed solvent and adding 100 parts of silica as a matting agent to 100 parts. A 110 mesh gravure coater was used to coat the surface of the produced leather-like sheet at a solid content of 3 g / m ² .
The obtained sheet is soft and the texture when the table is bent inward is delicate and has an excellent appearance like natural leather for shoes,
It was useful as a leather substitute for cases and the like.

[0041]

Comparative Example 1 The needle punch web used in Example 1 was treated in warm water at 50 ° C. to reduce the shrinkage to 25%, and the apparent density was adjusted to 0.17 g / cm ³ using a belt press. Using this nonwoven fabric, the same processing as in Examples 1, 2, and 3 was performed to prepare a sheet. The resulting sheet had sharp wrinkles and had poor wrinkles when processed into shoes or the like, and was not a preferred substitute for leather.

[0042]

Comparative Example 2 Polyurethane having a molecular weight of 1500 was synthesized from polytetramethylene glycol, dicyclohexylmethane diisocyanate, and diaminodicyclohexylmethane in place of the polyurethane elastomer [A] used in Example 1.
Sheets were prepared in the same manner as in Examples 1, 2, and 3 using polyurethane having a 00% elongation stress of 70 kg / cm ² and a cutting elongation of 450%. In each case, when the sports shoes were made and worn when the athletic shoes were harder than those of the sheet-like materials of Examples 1, 2 and 3 of the present invention, cracks occurred along the fibers of the nonwoven fabric, and the appearance was extremely poor.

[0043]

Comparative Example 3 The mixed solvent used in Example 1 was MEK / TO
Except for L / DMF = 20/40/40, the same processing as in Example 1 was performed to prepare a sheet. When a coating composed of a solution of the polyurethane elastomer [A] was applied, the surface of the polyurethane-impregnated nonwoven fabric was roughened, and even after the treatment of Examples 2 and 3, only poor surface smoothness was obtained.

[0044]

Example 4 Synthesis of Polyurethane Elastomer [A] Polyethylene glycol having a molecular weight of 2884 and a molecular weight of 28
7 of polyhexamethylene carbonate diol of 00:
750 parts of the mixture of No. 3 and 210 parts of dicyclohexylmethane diisocyanate were placed in a reactor equipped with a stirrer and purged with nitrogen, reacted at 90 ° C. for 80 minutes, and then methyl ethyl ketone (MEK) / toluene (TOL) / dimethylformamide (DMF) = 50/42. Solvent 2 mixed at a ratio of / 8
100 parts were added and dissolved, and cooled to 40 ° C. Then, a solution obtained by dissolving 39 parts of 1,2-propylenediamine in 90 parts of the same mixed solvent was added little by little, and a chain extension reaction was carried out for 6 hours. Then, 3.5 parts of dibutylamine was added to stop the reaction. Was obtained.

After the obtained polymer solution was diluted to 10% by weight with DMF, the solution was cast on a glass plate with a weir and heated at 50 ° C.
, And then vacuum dried at 80 ° C. for 2 hours to prepare a polyurethane film. The 100% elongation stress measured on this film is 20 kg / cm ² and the elongation at break is 80.
It was 0%. Using this, the same treatment as in Example 1 was performed to prepare a leather-like sheet. The obtained sheet has a moisture permeability of 1
0.5 mg / cm ² · hr and 6.5 mg / cm ² · of Example 1
The moisture permeability of the sheet of this example was superior to hr.

[0046]

Comparative Example 4 750 parts of a 7: 3 mixture of polyethylene adipate having a molecular weight of 2800 and polyhexamethylene carbonate diol having a molecular weight of 2800, and 210 parts of dicyclohexylmethane diisocyanate were placed in a reactor equipped with a nitrogen-substituted stirrer and reacted at 90 ° C. for 80 minutes. After that, 2100 parts of a solvent mixed at a ratio of methyl ethyl ketone (MEK) / toluene (TOL) / dimethylformamide (DMF) = 50/42/8 was added, dissolved and cooled to 40 ° C. Then, a solution obtained by dissolving 39 parts of 1,2-propylenediamine in 90 parts of the same mixed solvent was added little by little, and a chain extension reaction was carried out for 6 hours. Then, 3.5 parts of dibutylamine was added to stop the reaction. Was obtained.

After diluting the obtained polymer solution to 10% by weight with DMF, the solution was cast on a glass plate with a weir and heated to 50 ° C.
, And then vacuum dried at 80 ° C. for 2 hours to prepare a polyurethane film. The 100% elongation stress measured on this film is 23 kg / cm ² and the elongation at break is 85.
It was 0%. Using this, the same treatment as in Example 1 was performed to prepare a leather-like sheet. The obtained sheet was placed under high temperature and high humidity conditions of 80 ° C. and 95% RH for one week, which were correlated with the practical durability, and the durability was evaluated. As a result, no abnormality was observed in the sheet obtained from Example 1, whereas Comparative Example 4
The sheet No. was deteriorated and had insufficient durability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI // D06M 101: 32 (58) Fields investigated (Int. Cl. ⁷ , DB name) D06N 3/18 DAA D04H 1/06 D04H 1/42 D06M 15/564 D06N 3/14 101

Claims (6)

(57) [Claims] 1. A web containing heat-shrinkable fibers is heat-treated into a non-woven fabric having an area shrinkage of at least 30%, and the non-woven fabric is hot-pressed to have an apparent density of 0.2 to 0.40 g / cm ^3.
Then, the fibrous base material is impregnated with a polyurethane elastic solution and the surface layer is coagulated so that both components of the fibers constituting the fibrous base material and the polyurethane elastic material are present in a composite form. After that, a) (a) an aliphatic and / or alicyclic diisocyanate, and (b) a molecular weight of 600 to
100% elongation stress obtained from 4000 polymer diols, (c) an aliphatic diamine and / or an alicyclic diamine, or a diol having a molecular weight of 200 or less 5 to 40 kg / c.
m ² , a polyurethane elastomer [A] having a breaking elongation of 600% or more, and b) a ketone, an ester, an ether, a cyclic ether, an alcohol and a hydrocarbon solvent having a boiling point of 60 to 150 ° C., singly or mixed. solvent,
Alternatively, a coating composed of a solvent in which an amide-based solvent is mixed with the solvent at a ratio of 20% or less to these solvents at least in a solid content of 2 to 5%.
A method for producing a leather-like sheet, comprising applying 0 g / m ² and drying to form a first layer. 2. A web containing heat-shrinkable fibers is heat-treated to form a nonwoven fabric having an area shrinkage of at least 30%, and the nonwoven fabric is hot-pressed to have an apparent density of 0.2 to 0.40 g / cm ^3.
Then, the fibrous base material is impregnated with a polyurethane elastic solution and the surface layer is coagulated so that both components of the fibers constituting the fibrous base material and the polyurethane elastic material are present in a composite form. After that, a) (a) an aliphatic and / or alicyclic diisocyanate, and (b) a molecular weight of 600 to
100% elongation stress obtained from 4000 polymer diols, (c) an aliphatic diamine and / or an alicyclic diamine, or a diol having a molecular weight of 200 or less 5 to 40 kg / c.
m ² , a polyurethane elastomer [A] having a breaking elongation of 600% or more, and b) a ketone, an ester, an ether, a cyclic ether, an alcohol and a hydrocarbon solvent having a boiling point of 60 to 150 ° C., singly or mixed. solvent,
Alternatively, a coating composed of a solvent in which an amide-based solvent is mixed with the solvent at a ratio of 20% or less to these solvents at least in a solid content of 2 to 5%.
0 g / m ² and dried to form a first layer.
% Elongation stress 40 to 150 kg / cm ^{2 1 to} 50 g of a coating material comprising a solution of polyurethane elastomer [B] in solid content
/ M ² coating, forming a second layer. 3. A web containing heat-shrinkable fibers is heat-treated into a nonwoven fabric having an area shrinkage of at least 30%, and the nonwoven fabric is hot-pressed to have an apparent density of 0.2 to 0.40 g / cm ^3.
Then, the fibrous base material was impregnated with a polyurethane elastic body, and the surface layer was coagulated so that both components of the fiber constituting the fibrous base material and the polyurethane elastic body were present in a composite form. Then, on the surface, a) (a) an aliphatic and / or alicyclic diisocyanate, and (b) a molecular weight of 600 to 40.
00 polymer diol, (c) aliphatic diamine and / or
Or a polyurethane elastomer having a 100% elongation stress of 5 to 40 kg / cm ² and a breaking elongation of 600% or more obtained from an alicyclic diamine or a diol having a molecular weight of 200 or less [A]
B) a single or mixed solvent selected from the group consisting of ketones, esters, ethers, cyclic ethers, alcohols and hydrocarbon solvents having a boiling point of 60 to 150 ° C, or a ratio of 20% or less of an amide solvent to these solvents. At least ² to 50 g / m ² in terms of solid content
Coating and drying to form the first layer, 100% elongation stress 40 ~
A second layer is formed from a coating of a solution of a polyurethane elastomer [B] of 150 kg / cm ^{2 at} a solid content of 1 to 50 g / m ² and a 10% elongation stress of 100 to 40 on the surface.
A method for producing a leather-like sheet, characterized in that a coating comprising a solution of a polyurethane elastomer [C] of 0 kg / cm ² is applied at a solid content of 1 to 20 g / m ² to form a third layer. 4. The polymer diol (b) of the polyurethane elastomer [A] is a polymer diol containing at least 50% by weight of an aliphatic carbonate diol or a polyalkylene ether diol alone or in a mixture.
4. The method for producing a leather-like sheet according to any one of items 1 to 3. 5. The method for producing a leather-like sheet according to claim 1, wherein the polyalkylene ether diol of the polymer diol (b) of the polyurethane elastomer [A] is polyoxyethylene glycol. 6. The method for producing a leather-like sheet according to claim 1, wherein at least 50% by weight of the polymer diol of the polyurethane elastomer [B] and the polyurethane elastomer [C] is polyoxyethylene glycol.