JP2002030579A - Plush leathery sheet-like product and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plush leathery sheet-like product having elegant appearance and durability such as light resistance. SOLUTION: This plush leathery sheet-like product comprises ultrafine fibers with a fineness of <=0.3 dtex and a polyurethane; wherein the above polyurethane is made using polymer diols containing 30-90 wt.% of polycarbonate diol and is contained at 20-60 wt.% in the sheet-like product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like sheet having an excellent appearance and excellent durability such as light resistance.

[0002]

2. Description of the Related Art A leather-like sheet obtained by impregnating a polymer sheet into a sheet made of a fiber has uniformity, dyeing fastness, and texture flexibility not found in natural leather. Its use has spread to furniture and seat applications. Higher durability is required as the applications for which it is used expand. In particular, leather-like sheet materials containing ultrafine fibers having a fineness of 0.3 dtex or less and polyurethane are excellent in surface touch and flexibility, but when used for a long period of time, the hair foot becomes partially long, tangled, or hair. There is a problem that a ball is generated and the appearance is changed or the ball is broken. One of the causes is deterioration of the polyurethane. Therefore, studies have been made on a highly durable polyurethane having excellent light resistance and hydrolysis resistance.

For example, polyurethanes using polyether-based diols (hereinafter referred to as polyether-based polyurethanes) are excellent in hydrolysis resistance, but have a problem of poor light resistance. Polyurethane using polyester diol (hereinafter, referred to as polyester-based polyurethane) is excellent in light resistance, but has a problem of poor hydrolysis resistance. Polyurethanes using polycarbonate diols (hereinafter referred to as polycarbonate-based polyurethanes) are excellent in both light resistance and hydrolysis resistance, but have a problem that the leather-like sheet obtained due to its hardness tends to be plastic-like. .

[0004] In particular, polyurethane using polyhexamethylene carbonate is known as a highly durable polyurethane, but a leather-like sheet made of the polyurethane has a plastic-like texture and is coarse and hard.
In particular, when used for nap-like artificial leather, the nap is short, and polyurethane is exposed on the surface, which tends to cause "irritation".

[0005] JP-A-5-5280 and JP-A-5-43647 describe that a polyurethane using an amorphous polycarbonate diol has both durability and flexibility. As an example of such an amorphous polycarbonate diol, it is described that a polyurethane using a copolycarbonate diol of 1,9-nonanediol and 2-methyl-1,8-octanediol has excellent durability and flexibility. Have been. However, even if such a special polyurethane is used, a leather-like sheet having an excellent nap and good quality and a soft texture cannot be obtained.

[0006] Also, Japanese Patent Application Laid-Open No. 11-81156 discloses that
Artificial leather using a specific water-based polyurethane resin,
It is described that it has an excellent heat resistance that enables an improvement in the processing yield and a long-term continuous operation of the dyeing machine, and a polycarbonate-based polyurethane is exemplified as one of the specific water-based polyurethanes. However, the leather-like sheet disclosed in this publication has a very small polyurethane content, and when used for a long period of time, the nap on the surface falls off and the appearance changes greatly. Has a problem that the woven fabric as a reinforcing material is exposed on the surface. In addition, when a nap-finished leather-like sheet is manufactured using such an aqueous polyurethane, if the amount of polyurethane to be added is increased for the purpose of improving durability, even if the amount of adhesion is slightly increased, the nap is extremely short. It becomes difficult to obtain a leather-like sheet material having both flexibility and durability because the material becomes soft and the texture becomes hard.

Further, when a nap-finished leather-like sheet is manufactured using a polycarbonate-based polyurethane, the nap length is extremely shortened only by a usual nap-forming treatment because the polyurethane is hard, so that the nap length has a preferable nap length. I couldn't do that. For this reason, the amount of the polyurethane to be applied must be reduced, and brush treatment, that is, abrasion loss is remarkably increased by such treatment, and a material having sufficient durability has not been obtained. As a means for solving the above problems, in producing a leather-like sheet, a method of obtaining a soft leather-like sheet by impregnating and wet-solidifying a polyurethane after imparting polyvinyl alcohol or the like to a fiber sheet is obtained. Previously known. According to this method,
It is said that the polyurethane is applied in a state where the fibers are covered with the polyvinyl alcohol, so that a void is formed between the fibers and the polyurethane after the polyvinyl alcohol is removed, so that a flexible sheet-like material is obtained. However, in practice, when the polyurethane is wet-coagulated, a part of the polyvinyl alcohol is dropped off, so that a sufficient space cannot be provided between the fiber and the polyurethane, and the desired appearance and flexibility cannot be obtained. Was.

As described above, conventionally, it has not been possible to obtain a nap-finished leather-like sheet having excellent flexibility, quality, and durability with a polycarbonate-based polyurethane.

[0009]

SUMMARY OF THE INVENTION In view of the background of the prior art, an object of the present invention is to provide a nap-finished leather-like sheet having not only flexibility and an elegant appearance but also durability such as light resistance. To provide.

[0010]

The present invention employs the following means in order to solve the above problems. That is, in a nap-finished leather-like sheet material mainly composed of ultrafine fibers of 0.3 dtex or less and polyurethane, the polyurethane uses a polymer diol containing 30% to 90% by weight of a polycarbonate diol,
20% by weight or more of the polyurethane in the sheet material.
A nap-finished leather-like sheet containing 0% by weight or less.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The fine fibers constituting the leather-like sheet of the present invention have a fineness of 0.3 dtex or less, but the material of the fine fibers is not particularly limited. In addition, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polypropylene terephthalate, and polyamides such as nylon 6 and nylon 6,6 can be used. The fineness of the ultrafine fibers is required to be 0.3 dtex or less in terms of flexibility and quality, but in the case of polyester fibers, it is 0.005 to 0.005 in terms of color development and ease of fiber separation.
Those having a range of 0.3 dtex are preferable, and those having a range of 0.001 to 0.1 dtex are preferable in the case of polyamide fibers. In particular, polyester-based ultrafine fibers having a fineness of 0.005 to 0.3 dtex have durability. It is more preferable in this respect. In addition, as long as the object of the present invention is not impaired, the above-mentioned ultrafine fibers can be mixed and used, or fibers thicker than 0.3 dtex may be mixed within a range not impairing the object of the present invention. Absent. The cross-sectional shape of the ultrafine fiber may be an ordinary round cross-section, or a triangular or + -shaped irregular cross-section.

According to the present invention, a polycarbonate diol is
% To 90% by weight, preferably 50% to 90% by weight, more preferably 70% to 90% by weight.
Polyurethane using a polymer diol containing not more than weight% is used.

When the content of the polycarbonate diol is less than 30% by weight, the durability is insufficient, which is not preferable. 90
Exceeding the weight% is not preferred because the texture becomes hard.

[0014] The polycarbonate diol referred to in the present invention is a polycarbonate diol having a diol skeleton linked via a carbonate bond to form a polymer chain and having hydroxyl groups at both ends. The diol skeleton is determined by the glycol used as a raw material, but the type thereof is not particularly limited. For example, 1,6-hexanediol, 1,5-hexanediol,
Pentanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol can be used.
In addition, at least two selected from these glycol groups
A copolymerized polycarbonate diol using at least one kind of glycol as a raw material is preferable because a leather-like sheet having particularly excellent flexibility and appearance can be obtained. In addition, when a leather-like sheet having excellent flexibility is obtained, it is preferable to introduce a bond other than a carbonate bond, for example, an ester bond, an ether bond, or the like into the polymer diol as long as durability is not impaired. Examples of the form for introducing such a chemical bond include a method in which a compound having an ether bond or an ester bond is mixed and polymerized when the polycarbonate diol is polymerized, or a method in which the polycarbonate diol and the other polymer diol are each independently polymerized. And the method used for the polymerization of polyurethane can be adopted.

It is necessary that the content of the polyurethane is not less than 20% by weight and not more than 60% by weight in the sheet. Although the above-mentioned polycarbonate-based polyurethane has excellent durability, it deteriorates when used for a long period of time. Therefore, when the polyurethane content is less than 20% by weight, even if the initial physical properties are good, However, it is not preferable because long-term use causes deterioration in quality and physical properties. Therefore, in order to obtain higher durability, the content of the polyurethane is preferably 25% by weight or more and 60% by weight or less, and 30% by weight or more and 60% by weight or less.
The following is more preferred. On the other hand, when the polyurethane content is 6
If it exceeds 0%, not only the texture becomes hard and cored, but also the polyurethane is visible from the surface and the quality is greatly reduced, so that the leather-like sheet of the present invention cannot be obtained, which is not preferable.

The use of a mixture of a polycarbonate diol or a copolymerized polycarbonate diol and another polymer diol is preferable in order to balance durability, flexibility and quality. As the polymer diol to be mixed with the polycarbonate diol, polytetramethylene glycol, polyneopentyl adipate diol, polycaprolactone diol, and poly 2,5-diethylpentane adipate are preferable because they can balance the feeling and the durability. The mixing ratio of these polymer diols is preferably from 5% by weight to 70% by weight, more preferably from 5% by weight to 50% by weight, and still more preferably from 5% by weight to 30% by weight. If the ratio is within the range, two or more polymer diols may be mixed and used in combination with the polycarbonate diol.

The molecular weight of these polymer diols is not particularly limited, and can be appropriately selected according to the target properties of the leather-like sheet.
If it is less than 00, the physical properties are improved but the texture is hard. If it is more than 3000, the texture is soft but the physical properties tend to be reduced.

Further, in the leather-like sheet material of the present invention, the average nap length is preferably 300 μm or more and 2000 μm or less. If the average nap length is less than 300 μm, the amount of polyurethane exposed on the surface increases, and the appearance becomes poor, which is not preferable. On the other hand, if the average nap length is longer than 2000 μm, the fibers cut by abrasion tend to be pills, which is not preferable because there is a problem that the abrasion resistance is reduced.

In the present invention, it is preferable that the weight loss by abrasion test is 25 mg or less. If the abrasion loss exceeds 25 mg, the pills will fall off sharply, making it difficult to form pills, but the appearance will change drastically, and in extreme cases,
Since the appearance becomes worn out, the high durability which is the object of the present invention cannot be obtained, which is not preferable.

In the present invention, the method for producing the polyurethane is not particularly limited, and a method in which a polymer diol and a diisocyanate are first reacted to form a prepolymer and then reacted with a chain extender as in a conventional method. Can be used. If necessary, a stabilizer such as an ultraviolet absorber or an antioxidant can be copolymerized.

The ratio between the polymer diol and the diisocyanate at this time is not particularly limited, and the polymer diol may be increased when importance is placed on flexibility, and the diisocyanate may be increased when importance is placed on durability. It is preferable to adjust the reaction conditions so that the molar ratio of the two becomes 1: 2 to 1: 5. When a plurality of polymer diols and diisocyanates are used, they may be separately reacted to form a plurality of prepolymers in advance and then mixed and reacted with a chain extender to obtain a structure close to a block copolymer, or may be mixed. Create a prepolymer in the state
The structure may be close to a random copolymer by reacting with a chain extender. Further, an organic tin compound, an organic titanium compound, a tertiary amine or the like can be added as a reaction catalyst.

The diisocyanate to be combined with the polymer diol is not particularly limited. For example, when heat resistance is important, an aromatic diisocyanate such as 4,4'-diphenylmethane diisocyanate can be used. When it is desired to suppress yellowing due to light, an alicyclic diisocyanate such as isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, or 1,6-hexamethylene diisocyanate, or an aliphatic diisocyanate can be used. Further, a plurality of these diisocyanates may be used in combination depending on the purpose.

The chain extender to be reacted with the above polymer diol and diisocyanate is not particularly limited, and a low molecular weight compound having two or more active hydrogens can be used. Diols such as 1,6-hexanediol and the like, polyalkylene glycols such as diethylene glycol and dipropylene glycol, aliphatic diamines such as ethylenediamine and isophoronediamine, and alicyclic diamines and aromatic diamines such as methylenebisaniline, alone or in combination. Can be used.

In particular, 4,4'-
When diphenylmethane diisocyanate and an aliphatic diol having 2 to 8 carbon atoms, particularly ethylene glycol, are used as a chain extender, a polyurethane excellent in durability and flexibility can be obtained, which is preferable.

In the present invention, as a method for obtaining the ultrafine fibers, a method for directly obtaining the desired ultrafine fibers and a method for once preparing a thick fiber and then expressing the ultrafine fibers can be adopted. In terms of the ease with which thin fibers can be obtained and the flexibility of the resulting leather-like sheet, a method in which once thick fibers are formed and then ultrafine fibers are developed can be preferably used. As such a method, for example, after spinning together a plurality of polymers having different solubilities to obtain a fiber capable of expressing ultrafine fibers,
A method of removing ultra-fine fibers by removing a kind of polymer can be used.

Examples of a composite form when spinning a fiber capable of expressing such ultrafine fibers include a side-by-side type in which polymers are bonded to each other, a sea-island type in which another polymer is present in the form of islands in a polymer, and a polymer. Can be preferably used in the form of a blend in which are mixed in the form of an alloy. As the type of the polymer to be removed, a polyolefin such as polyethylene or polystyrene, a copolymerized polyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, or the like to increase alkali solubility can be used.

Next, the method of developing the ultrafine fibers differs depending on the type of the component to be removed. For a polyolefin such as polyethylene and polystyrene, an organic solvent such as toluene and trichloroethylene, and for a copolymerized polyester, a hydroxide is used. Immerse in an alkaline aqueous solution such as sodium
A method for performing stenosis can be preferably used.

Next, a method of forming a sheet using the above fibers will be described. The sheet is not particularly limited, and a woven fabric, a knitted fabric, a nonwoven fabric, and a composite thereof can be appropriately selected and used according to the purpose.

As such a woven fabric, a normal plain weave or twill weave can be used, and as a knit, a knitting or a tubular knit can be used. In addition, as the nonwoven fabric, short fiber nonwoven fabric,
Any long-fiber non-woven fabric may be used, but short-fiber non-woven fabric is preferred when emphasis is placed on texture and quality.

As a method for obtaining such a short-fiber nonwoven fabric,
A method using a card, a cross wrapper, a random webber, or a papermaking method can be employed. Further, the nonwoven fabric obtained by these methods can be entangled with a needle punch or a water jet punch, or can be integrated with another woven fabric, knitted fabric or nonwoven fabric.

In producing the leather-like sheet material of the present invention, it is possible to adopt a method in which ultrafine fibers are first prepared and then formed into a sheet, or the above-mentioned fibers capable of expressing ultrafine fibers are formed into a sheet. Later, a method in which the above treatment is performed to express the ultrafine fibers may be adopted.

The sheet-like material thus obtained is subjected to polyurethane treatment and nap formation processing. In addition, it is preferable that the order of the polyurethane application and the napped formation treatment is appropriately selected depending on the type of the sheet material. For example, for a fabric that is difficult to form nap such as a woven fabric, it is possible to adopt a process of first forming nap, then applying polyvinyl alcohol, further applying polyurethane, and if necessary, again performing nap formation processing. , A preferred means for obtaining good standing hair.

As a method of imparting polyurethane, a method of impregnating a sheet-like material with a polyurethane solution and further immersing the same in water or an aqueous solution of an organic solvent to coagulate the polyurethane is preferable. As a solvent used for such a polyurethane solution, N, N'-dimethylformamide, dimethylsulfoxide and the like can be preferably used. Further, addition of another solvent or water within a range that does not hinder the solubility of the polyurethane is also a preferable means in terms of forming nap. Also,
For the purpose of adjusting the coagulation structure of the polyurethane, a coagulation regulator such as a higher alcohol or a surfactant can be added. Further, a pigment, an ultraviolet absorber and an antioxidant can be added as needed. In the present invention, (1) a step of imparting polyvinyl alcohol having a saponification degree of 90% or more to a fiber sheet material;
A step of impregnating a polyurethane solution using a polymer diol containing not less than 90% by weight and not more than 90% by weight and coagulating it in water or an aqueous solution of an organic solvent at not more than 50 ° C. (3) The step of substantially completely removing polyvinyl alcohol By performing the steps in this order, the falling off of polyvinyl alcohol during wet coagulation can be almost completely suppressed, and high flexibility and durability, which have been difficult in the past, can be achieved.

In this case, if the degree of saponification of the polyvinyl alcohol is low, the falling off of the polyvinyl alcohol during wet coagulation cannot be completely suppressed, and the desired texture cannot be obtained. , More preferably 95% or more, further preferably 99% or more.

If the temperature during wet coagulation is higher than 50 ° C., the polyvinyl alcohol will fall off.
It is preferably 0 ° C. or lower. Further, the solidification temperature is more preferably 40 ° C. or less, further preferably 30 ° C. or less,
When the temperature is most preferably 10 ° C. or lower, a leather-like sheet having a softer texture can be obtained. A further effect can be exhibited by combining such low-temperature coagulation with the above-mentioned high saponification degree polyvinyl alcohol.

In order to obtain higher flexibility, it is desirable to add a heat treatment step in order to further completely prevent the falling off of polyvinyl alcohol during wet coagulation. If the heat treatment temperature in this case is lower than 120 ° C., falling off of polyvinyl alcohol during wet coagulation cannot be completely suppressed, and if it is higher than 190 ° C., polyvinyl alcohol becomes insoluble and cannot be completely removed later. Not preferred. Therefore, the heat treatment temperature is preferably 120 ° C. or more and 190 ° C. or less.
It is more preferable that the temperature is 0 ° C. or lower.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to embodiments.

All mixing ratios used in the examples are weight ratios unless otherwise specified.

The abbreviations used in the examples have the following meanings.

EG: ethylene glycol DMF: N, N′-dimethylformamide MBA: methylenebisaniline MDI: 4,4′-diphenylmethane diisocyanate PCL: polycaprolactone diol PHC: polyhexamethylene carbonate diol PTMG: polytetramethylene glycol The evaluation method in the example is as follows. (1) Durability After irradiating light for 100 hours with a sunshine carbon arc lamp type light resistance tester specified in JIS B7753, the temperature was changed to 7
A 4.5 cm-diameter circular sample that had been subjected to a forced deterioration treatment that was left in an atmosphere at 0 ° C. and a relative humidity of 95% for 3 weeks was subjected to
Rubbing was performed under the Martindale abrasion test conditions specified in IS L1906, and the appearance of which did not change at all from the level before the abrasion was grade 5; It was visually evaluated at the stage, and a grade 4 or higher was judged as a pass. (2) Flexibility For five testers who have three or more years of experience developing textile products,
Let 10 be the highest, and 5 or more be evaluated in 10 grades,
Evaluation was made based on the average score. (3) Average nap length A photograph magnified 100 times was taken with an optical microscope, and the average nap length was determined from the length of 50 naps randomly extracted. (4) Weight reduction by brush abrasion test As described below, the surface of a 4.5 cm diameter circular sample subjected to the above-mentioned forced deterioration treatment was abraded by rotating a predetermined brush under a constant load, and the weight change before and after that. Was measured. (A) Brush: 100 nylon yarns having a length of 1.1 mm and a diameter of 0.4 mm are aligned to form a bundle, and the bundle is made of 110 mm in diameter.
(B) Load: 3600 g (c) Number of rotations: 45 (rotation speed: 65 rpm) Example 1 Polymer diol having a molecular weight of 2,000 PHC and
A 55:45 mixture of PTMG having a molecular weight of 2,000, MDI as a diisocyanate and EG as a chain extender were used to obtain a polyurethane by a conventional method, and the solid content was 12% by weight.
And a 1.5% by weight of a benzophenone-based ultraviolet absorber was added as an additive to prepare a polyurethane impregnating liquid.

Separately, sea-island composite fibers were prepared using a sea-island type composite yarn base. The compound conditions are as follows. Sea component: polystyrene Island component: polyethylene terephthalate Sea-island ratio: 30% sea, 70% island The sea-island composite fiber was stretched 3.1 times, further crimped, and then cut to obtain a raw cotton. The raw cotton was formed into a web using a cross wrapper, and further subjected to needle punching to obtain a nonwoven fabric. The nonwoven fabric was impregnated with a 10% aqueous solution of polyvinyl alcohol having a saponification degree of 95%, then squeezed and dried at 160 ° C. Thereafter, the sea component was extracted with trichlorethylene to obtain a fiber sheet made of ultrafine fibers of 0.08 dtex.

The fibrous sheet was immersed in the above-mentioned polyurethane impregnating liquid, and the amount of the polyurethane impregnating liquid applied was adjusted with a squeezing roll. Then, the polyurethane was coagulated in a 45% DMF aqueous solution at 20 ° C. Thereafter, DMF and polyvinyl alcohol were removed with hot water at 85 ° C., and after drying, the sheet was buffed and dyed with a disperse dye to obtain a leather-like sheet.

As shown in Table 1, the average nap length of this leather-like sheet was 1015 μm, and the weight loss by the brush abrasion test was 21 mg. The leather-like sheet has an elegant appearance, a durability of 5th grade, and a flexibility of 7th.
It was a point and had excellent durability and flexibility. Comparative Example 1 The mixing ratio of PHC and PTMG in the polymer diol was 1
A leather-like sheet was obtained in the same manner as in Example 1 except that the ratio was 5:85.

As shown in Table 1, the average nap length of this leather-like sheet was 1312 μm, and the weight loss by the brush abrasion test was 23 mg. The leather-like sheet had an elegant appearance, and had a flexibility of 8 points.
The durability was first class, and although the flexibility was excellent, the durability was poor. Comparative Example 2 PCL having a molecular weight of 2,000 and PTMG having a molecular weight of 2,000
A leather-like sheet was obtained in the same manner as in Example 1 except that the mixture at 55:45 was used as the polymer diol.

The average nap length of the leather-like sheet is 11
39 μm, and the weight loss by the brush wear test was 1
9 mg. Further, the leather-like sheet-like material had an elegant appearance and had seven points of flexibility. However, the durability was of the first grade, and although the flexibility was excellent, the durability was poor. Example 2 A 75:25 mixture of PHC having a molecular weight of 2,000 and PCL having a molecular weight of 2,000 as a polymer diol, MDI as a diisocyanate, and MBA as a chain extender were used to obtain a polyurethane by a conventional method so that the solid content was 14% by weight. Was diluted with DMF to prepare a polyurethane impregnating liquid.

Separately, sea-island composite fibers were prepared using a sea-island type composite yarn base. The compound conditions are as follows. Sea component: polystyrene Island component: polyethylene terephthalate Sea-island ratio: 50% sea, 50% island The sea-island composite fiber was stretched 2.9 times, further crimped, and then cut to obtain raw cotton. The raw cotton was formed into a web using a cross wrapper, and further subjected to needle punching to obtain a nonwoven fabric. After impregnating the nonwoven fabric with a 13% aqueous solution of polyvinyl alcohol having a degree of saponification of 90% or more, squeezing, 150 ° C.
And dried. Thereafter, the sea component was extracted with trichlorethylene to obtain a fibrous sheet made of ultrafine fibers of 0.13 dtex.

The fibrous sheet was immersed in the above-mentioned polyurethane impregnating solution, and the amount of the polyurethane impregnating solution applied was adjusted with a squeezing roll. Then, the polyurethane was coagulated in a 20% aqueous DMF solution at 15 ° C. After that, DMF and polyvinyl alcohol were removed with hot water at 85 ° C., dried, and silicone oil was applied to the sheet surface with a gravure coater, dried, buffed, and dyed with a disperse dye to form a leather-like sheet. I got something.

As shown in Table 1, the average nap length of the leather-like sheet was 982 μm, and the weight loss by the brush abrasion test was 18 mg. The leather-like sheet had an elegant appearance, a durability of 5th grade and a flexibility of 6 points, and had both excellent durability and flexibility. Comparative Example 3 The drying temperature after applying the aqueous polyvinyl alcohol solution was 1
A leather-like sheet was obtained in the same manner as in Example 2, except that the temperature of the DMF aqueous solution at the time of coagulation of the polyurethane was set to 45 ° C, and the silicone oil was not applied before buffing.

As shown in Table 1, the average nap length of this leather-like sheet was 279 μm, and the weight loss by the brush abrasion test was 9 mg. In addition, the leather-like sheet has a poor appearance in which polyurethane is exposed on the surface,
Although the durability was grade 5, the flexibility was 3 points, and although the durability was excellent, the quality and the flexibility were poor. Comparative Example 4 The drying temperature after applying the aqueous polyvinyl alcohol solution was 1
A leather-like sheet was formed in the same manner as in Example 2 except that the temperature of the polyurethane solution to be impregnated was 9%, the temperature of the DMF aqueous solution at the time of coagulation of the polyurethane was 45 ° C, and no silicone oil was applied before buffing. I got something.

As shown in Table 1, the average nap length of the leather-like sheet was 938 μm, and the weight loss by the brush abrasion test was 45 mg. Further, the leather-like sheet-like material had an elegant appearance and had nine points of flexibility, but had a second-class durability. Although it was excellent in quality and flexibility, it was inferior in durability. Was. Example 3 A mixture of neopentyl glycol and 1,6-hexanediol in a molar ratio of 30:70 was subjected to polycondensation to obtain a copolymerized polycarbonate diol having a molecular weight of 2,000.

A leather-like sheet was obtained in the same manner as in Example 1 except that a mixture of the above-mentioned copolymerized polycarbonate diol and PCL having a molecular weight of 2000 at a ratio of 80:20 was used as the polymer diol.

As shown in Table 1, the average nap length of this leather-like sheet was 1027 μm, and the weight loss by the brush abrasion test was 19 mg. The leather-like sheet has an elegant appearance, a durability of 4th grade, and a flexibility of 7th.
This is a point that has both excellent durability and flexibility. Comparative Example 5 The concentration of the polyvinyl alcohol liquid to be impregnated was set to 16%,
A leather-like sheet was obtained in the same manner as in Example 3 except that silicone oil was applied with a gravure coater before buffing.

As shown in Table 1, the average nap length of this leather-like sheet was 2319 μm, and the weight loss by the brush abrasion test was 23 mg. The leather-like sheet material had an elegant appearance and had eight points of flexibility, but had a second-class durability. Although it was excellent in quality and flexibility, it was inferior in durability. Was.

[0054]

[Table 1]

[0055]

According to the present invention, it is possible to obtain a leather-like sheet having an excellent appearance and excellent durability such as light resistance.

Claims (6)

[Claims] 1. A nap-finished leather-like sheet comprising mainly ultrafine fibers of 0.3 dtex or less and polyurethane, wherein the polyurethane comprises 3% of polycarbonate diol.
A nap-finished leather-like sheet comprising a polymer diol containing from 0% to 90% by weight, wherein the polyurethane is contained in the sheet from 20% to 60% by weight. 2. The method according to claim 1, wherein the polymer diol comprises at least one polymer diol selected from the group consisting of polytetramethylene glycol, polyneopentyl adipate diol, polycaprolactone diol and poly 2,5-diethylpentane adipate in an amount of 5% by weight or more. 2. The napped leather-like sheet according to claim 1, comprising not more than 10% by weight. 3. The polycarbonate diol comprises at least two kinds of glycols selected from the group consisting of 1,6-hexanediol, 1,5-pentanediol, neopentyl glycol and 3-methyl-1,5-pentanediol. 3. The composition according to claim 1, which is obtained by copolymerization.
The nap-finished leather-like sheet according to 1. 4. The nap-finished leather-like sheet according to any one of claims 1 to 3, wherein the average nap length is 300 μm or more.
A nap-finished leather-like sheet material having a thickness of 0 μm or less and a weight loss of 25 mg or less in a brush abrasion test. 5. A process for producing the napped leather-like sheet according to any one of claims 1 to 4, wherein (1) a step of imparting polyvinyl alcohol having a saponification degree of 90% or more to the fiber sheet. (2) A step of impregnating the fiber sheet-like material with a polyurethane solution using a polymer diol containing 30% by weight or more and 90% by weight or less of polycarbonate diol, and coagulating the same in water or an organic solvent aqueous solution at 50 ° C. or less. (3) a step of substantially completely removing polyvinyl alcohol; Are carried out in this order. 6. The napped leather-like sheet according to claim 5, wherein after the polyvinyl alcohol is applied to the fiber sheet, the sheet is heat-treated at a temperature of 120 ° C. or more and 190 ° C. or less. Method of manufacturing a product.