JP3391982B2 - Leather-like sheet with good air permeability and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a silver surface on the surface of which fine pores having a polyurethane fiber bridging structure are formed, and between the silver surface and an underlying substrate layer. The present invention relates to a silver-leathered leather-like sheet having a feeling of unity, a high-grade appearance with no particular irritability, and excellent air permeability and moisture permeability, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, many proposals have been made regarding a method for producing a leather-like sheet having a silver surface. Most of these proposals are methods of forming a silver surface by providing a wet coagulation layer or a dry coagulation layer made of an elastic polymer on one surface of a fibrous sheet. Many proposals have also been made for a method for producing a leather-like sheet with silver having air permeability and moisture permeability. Those methods include a method of laminating a breathable porous layer formed by a wet coagulation method or a dry coagulation method by adding a foaming agent, an additive, a coagulation regulator, etc. to the fibrous surface, or a surface by a laser beam or the like. And the method of making a hole in the silver surface layer.

As a method for producing a leather-like sheet having a natural leather-like appearance and further having air permeability and moisture permeability, a method of heat-melting the surface of a fibrous sheet containing an elastic polymer, or a method of forming fibers or elasticity on the surface A method has been proposed in which a solvent for a polymer is applied and the fibers or elastic polymer constituting the surface of the sheet are melted to smooth the surface and form a silver surface (for example, JP-B-48-535, JP-B-48-536, JP-B-48-537, etc.). Further, a leather in which an ultrafine fiber napped surface is formed on the surface of the fiber entangled body, the solvent or swelling agent of the fiber is applied, the fibers are joined by hot pressing to smooth the surface, and the elastic polymer coating layer is further provided on the surface. A method for manufacturing such a sheet is also known.

[0004]

However, among the methods proposed hitherto, in the case of a method of providing a porous layer made of an elastic polymer on the surface of a fiber sheet, the obtained sheet has air permeability. I am not satisfied with. Further, in the case of this method, there are problems that the silver surface has a strong rubber repulsion sensation and the surface has a bad wrinkle morphology. In the case of the method of making holes in the coating layer on the surface with a laser or the like, the air permeability is satisfactory, but the appearance is not high-grade.
Further, in the case of a method in which the fibers and elastic polymer constituting the fibrous sheet are melted by heat or melted by a solvent to smooth and form a silver surface, the air permeability and moisture permeability are satisfactory, but the surface becomes hard. However, the product lacks a sense of fulfillment and also has a feeling of frustration in appearance, resulting in a lack of luxury. INDUSTRIAL APPLICABILITY The present invention has a base layer and a silver surface that have a sense of unity and fulfillment like natural leather, and have a high-grade appearance with no irritating appearance, and also have excellent air permeability and moisture permeability. A leather-like sheet and a method for manufacturing the same.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a base layer composed of a fiber-entangled nonwoven fabric and an elastic body contained therein,
10-100 μm thick formed on at least one surface
A leather-like sheet consisting of the urethane coating layer, wherein the polyurethane coating layer has fine pores with a diameter of 300 μm or less.
It is a leather-like sheet characterized by having 0 or more / cm ² and having a polyurethane fiber bridging structure in some of the fine pores.

The fibers constituting the fiber-entangled nonwoven fabric of the base layer used in the present invention are made of ultrafine fiber-generating fibers composed of at least two kinds of polymers. For example, when the sea component is dissolved or decomposed by a solvent or a decomposing agent such as sodium hydroxide, the island component is fibrillated. Extractable fibers having a sea-island structure in cross section or ultrafine fibers made of each polymer mechanically or by a treating agent. Examples include split fibers that are fibrillated into fibers. Of course, it may be composed of fibers having an ordinary thickness, or may be a mixture of the above ultrafine fiber-generating fibers and ordinary fibers. However, it is preferably a non-woven fabric made of the above ultrafine fiber-generating fiber.

As the polymer constituting the ultrafine fibers, 6
-Nylon, 66-Nylon and other melt-spinnable polyamides, polyethylene terephthalate, polybutylene terephthalate, melt-spinnable polyesters such as cationic dyeable modified polyethylene terephthalate, and polyolefins represented by polypropylene At least one polymer selected from the group consisting of: Further, as the component extracted or decomposed and removed by the extraction type fiber, a polymer having different solubility or decomposability with respect to the solvent or the decomposing agent with the ultrafine fiber component, and having a small compatibility with the ultrafine fiber component, and the spinning condition It is a polymer having a lower melt viscosity or a lower surface tension than the ultrafine fiber component, and is, for example, at least one polymer selected from polymers such as polyethylene, polystyrene, polyethylene propylene copolymer and modified polyester. The amount ratio of the sea component to the island component of this ultrafine fiber is 1: 2 to 2: 1, and the suitable denier after extracting the sea component is 0.01 to 0.
A range of 0001dr is good.

Next, the fiber entangled non-woven fabric is impregnated with an elastic resin liquid, and is gelled by heating and drying, or is immersed in a liquid containing a non-solvent of the elastic resin and wet-solidified to form a dense foam sponge. Form. Examples of the elastic resin to be impregnated here include at least one polymer diol selected from polyester diols, polyether diols, polycarbonate diols, polyester polyether diols and the like having an average molecular weight of 500 to 3000, and 4,4′-diphenylmethane. At least one diisocyanate compound selected from aromatic, alicyclic or aliphatic diisocyanates such as diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate, and at least one kind having at least two active hydrogen atoms molecular weight 300 the following compounds of low molecular compounds, such as ethylene glycol, propylene glycol, 1.4 over butanediol, hexanediol, 3 Mechiru 1,5 Pentanjio le, 1 Diols such as 4-cyclohexanediol and xylene glycol, diamine compounds such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine and tolylenediamine; hydrazines and hydrazides such as adipic acid hydrazide and isophthalic acid dihydrazide. It is a polyurethane obtained by reacting with at least one selected from the above.

[0009] Particularly preferred is polyurethane obtained by reacting a chain extender consisting mainly of 1,4-butanediol or 3 Mechiru 1,5 Pentanjio Le at a predetermined molar ratio. In addition to polyurethane, other elastic resin such as polyester elastomer and acrylic resin may be used. Also, a polymer composition obtained by mixing these may be used. However, the above-mentioned polyurethane is preferably used because of its flexibility, elastic recovery property, sponge forming property and the like. The elastic resin concentration in the elastic resin liquid is preferably 10 to 50% by weight, and the Young's modulus is preferably 1 to 15 kg / mm ² . As the polyurethane, the molar ratio of the polymer diol and the low molecular weight compound is preferably in the range of 1: 1 to 1: 7.

In the present invention, the resin constituting the silver surface is polyurethane, and the silver surface layer is formed by heating and pressing a polyurethane non-woven fabric to form a film, which is composed of such a polyurethane non-woven fabric. As a result, the excellent performance of the present invention described above can be obtained.

As the polyurethane constituting the silver surface of the present invention, low molecular diols such as ethylene glycol, propylene glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-Pentanjio least one dicarboxylic acid selected from the Le like, such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic Polyester glycol such as polyester diol, polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol and polyhexamethylene ether glycol obtained by condensation polymerization with at least one selected from acids, isophthalic acid, terephthalic acid, etc. At least one type of polymer diol selected from polylactone glycols such as polycaprolactone glycol and polyvalerolactone glycol, wherein the polymer diol having an average molecular weight of 500 to 3000 is soft. It is a polyurethane to a segment. In particular, it is preferable to use a polyester diol having an average molecular weight of 700 to 3000 obtained by condensation polymerization of a diol mainly composed of 3-methylpentanediol-1,5 and a dicarboxylic acid, the melt moldability of polyurethane, solvent stability, and hydrolysis resistance. From the viewpoint of heat resistance, weather resistance, heat resistance, flexibility, bending resistance, etc., 100 micropores with a diameter of 300 μm or less are used.
The number of holes / cm ² or more is preferable, and at least a part of the fine pores is preferable in that a silver surface layer having a bridging structure of polyurethane fibers can be easily formed.

Examples of the organic diisocyanate to be reacted with the polymer diol include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate,
Aromatic diisocyanates such as phenylene diisocyanate and xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4.4 '
-At least one selected from aliphatic or alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, etc., or organic triisocyanate within the range that does not impair melt spinnability or melt moldability An organic polyisocyanate having 3 or more isocyanate groups may be used in combination.

As a chain extender, active hydrogen atom 2
Molecular weight of 300 or less of the compound having pieces, such as ethylene glycol, propylene glycol, 1,4-butanediol, hexanediol, 3-methyl-1,5 Pentanjio Le, 1,4-cyclohexanediol, diols such as xylene glycol At least one selected from diamines such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine, and tolylenediamine, hydrazine such as adipic acid hydrazide, and isophthalic acid dihydrazide, and hydrazides. . Particularly preferably, 1,4-butanediol or 3-methyl -
A polyurethane using a chain extender consisting mainly of 1,5 Pentanjio Le. The molar ratio of the polymer diol to the chain extender can be freely changed depending on the physical properties of the nonwoven fabric, but it is preferably about 1: 2 to 7.

Next, as a method for producing a silver surface composed of an aggregate of fibers mainly composed of polyurethane fibers, for example, there is a method of using a non-woven fabric made from a melted state of polyurethane by a melt blown method, In the case of this method, a leather-like sheet having excellent air permeability and improved processing efficiency can be obtained. The thickness of the non-woven fabric used in this method is 50 to 500 μm, especially 100 to 400 μm.
m is preferable, and the fiber diameter is 2 to 20 μm, especially 4
The range of 10 μm is preferable. If the polyurethane impregnated in the base layer is a polyester-based polyurethane, it is advisable to use a non-woven fabric made of the same type of polyurethane as the base layer, such as a polyester surface polyurethane for the silver surface forming non-woven fabric. Is preferable in consideration. The basis weight of the polyurethane nonwoven fabric is preferably 5 to 125 g / m ² , and particularly preferably 25 to 100 g / m ² in consideration of the surface condition and air permeability. As a method of heat-melting and bonding, a heating press by embossing is performed at a temperature of 20 ° C to 20 ° C from the softening point of the polyurethane fiber.
80 ° C. high temperature and pressure 0.5-7.0 kg / cm ²
It is preferable to laminate and integrate. However, if the adhesive is adhered at a temperature lower than the softening point by 20 ° C. or higher, the adhesiveness will be poor, and if the temperature is 80 ° C. or higher, the fine pores will be excessively crushed to cause poor air permeability. Therefore, the bonding temperature is 20 to 8 with respect to the softening point of the polyurethane.
A temperature range of 0 ° C. higher is preferred.

The softening point of polyurethane is determined by a trace melting point measuring device (YANAGIMOTO XTZ-OL-22). Next, the bonding pressure is 0.5 kg
Laminating at a pressure lower than / cm ² results in poor adhesion,
At a pressure higher than 7.0 kg / cm ² , the texture becomes hard. Therefore, the laminating pressure is 0.5 to 7.0 kg.
The range of / cm ² is preferable. The coat layer thus obtained has a coat thickness of 10 to 100 μm. The coat thickness referred to here is the average of the thicknesses obtained from electron micrographs.

The polyurethane nonwoven fabric is formed into a film by heating and pressing, but the film has fine pores. If the diameter of the fine pores exceeds 300 μm, the feeling of irritability becomes poor and the appearance deteriorates. Therefore, it is necessary to be 300 μm or less, preferably 100 μm or less. The number of micropores present is 100 / cm ² , preferably 300 / cm.
It is 2 or more, and the air permeability is improved by satisfying this number. However, if it exceeds 5000 pieces / cm ² , some irritating feeling is generated, which is not preferable. More preferably 3,000 or less under 300 or more.

In the present invention, it is extremely important that at least a part of the fine pores has a bridging structure of polyurethane fibers in order to eliminate the feeling of irritability. The proportion of those having a bridging structure eliminates the irritating feeling if it is 10% or more of all the fine pores, and is preferably 30% or more. The term "micropores having a bridging structure" as used in the present invention means that the surface of the sheet is arbitrarily selected and observed from an electron micrograph, and the average distance between the micropores is 30 µ or more, and the fiber diameter inside the micropores is 3 µ or more. One or more fibers are present in a bridged state (Fig. 1). It is not always clear why having a polyurethane fiber bridging structure is effective in eliminating the irritating feeling, but the light that has entered the micropores is blocked by the bridging fiber. It is predicted that this is due to the inability to get out of the hole.

The number of holes and the size of the holes on the surface with silver are determined by coloring with a resin and a colorant diluted with a solvent having a solvent composition of less than 10% by weight of dimethylformamide during coloring. It is possible to color the micropores without crushing. On the other hand, when it is 10% by weight or more, the fine pores on the surface are crushed and the air permeability is impaired. Then, if necessary, finish treatment such as embossing, dyeing, softening treatment, and fir treatment is carried out by a known method to finish the leather-like sheet with silver. In the present invention, pores having a diameter of more than 300 μm may be present if the amount is very small. The micropore diameter is defined as the diameter of a circle having the same area as the surface area of the hole.

The silver-like leather-like sheet obtained by the present invention is composed of a silver surface having fine pores having a polyurethane fiber bridging structure on the surface, and the silver surface and the underlying base layer provide a sense of unity. A silver-like leather-like sheet having a certain texture, and also having excellent air permeability and moisture permeability and an extremely excellent appearance with no particular irritability. Therefore, the silver leather sheet of the present invention is suitable for use in men's shoes, sports shoes, general shoes and the like.

[0020]

EXAMPLES The embodiments of the present invention will now be described with reference to specific examples, but the present invention is not limited to these examples. The parts and% in the examples are unless otherwise specified.
It is about weight.

Example 1 A staple fiber obtained by cutting a 6-denier sea-island type fiber having a fiber length of 51 mm, which is made of high-fluidity polyethylene (sea component) and 6-nylon (fine fiber bundle fiber island component), as a base layer. Was used to prepare a dry fiber web, which was used as a laminated web by the cross lap method, and the fibers were entangled by the needle punching method and heat-treated to give a nonwoven fabric having a basis weight of 300 g / m ² . Polyester polyurethane (chain extender is 1,
4-butanediol was impregnated with a 20% dimethylformamide solution in which the molar ratio of the polymer diol and the chain extender was 1: 4, the urethane adhering to the surface was cut with a knife, and then solidified in an aqueous dimethylformamide solution. Then, the solvent dimethylformamide was removed by washing with warm water, and polyethylene in the fiber was dissolved and removed with hot toluene to obtain an average number of ultrafine fiber bundles of 1000 / bundle and an average fineness of 0.001 deniers of 6-nylon ultrafine fibers. A fiber sheet made of entangled nonwoven fabric and porous polyurethane was obtained.

Then, poly-3-methyl-1.5-pentyl adipate glycol having an average molecular weight of 1150, 4.4-diphenylmethane diisocyanate and 1.4-butanediol are mixed in a molar ratio of 1: 4: 3 (theoretical nitrogen amount based on the isocyanate group is 4 .63%), and polyurethane was polymerized by a melt polymerization method using a screw type kneading type polymerization machine. The softening point of this polyurethane was 125 ° C. The obtained polyurethane was melt-blown in a molten state, and the fibrous molten polyurethane was conveyed into fine fibrous form by a high-speed air stream heated to a temperature of 260 ° C. from slots on both sides of a die orifice heated to a temperature of 260 ° C. It was collected at a position of a collection distance of 40 cm on a wire net moving at a speed of 1 / min. The collected web was a fine fiber random web having an average basis weight of 74 g / m ² , an average thickness of 0.3 mm, and an apparent density of 0.25 g / cm ³ .

This non-woven fabric is placed on the above fiber sheet,
Pressing pressure 4kg / cm with embossing roll heated to 0 ℃
Melt adhesion was performed under a pressure of ² to obtain a leather-like sheet with silver.
This silver-like leather-like sheet has an air permeability of 2.5 cc / cm ^2.
/ Sec, it had a high-class leather-like appearance with no irritability. And on the surface there are about 800 micropores with an average of 70μ /
cm ^{2 was} present and micropore bridging was seen. The thickness of the coating layer was 50μ. Furthermore, the grain-sheet black ink MT over 6701 (Dainichi Seika Co.): isopropyl alcohol: Echiruse B cellosolve = 2: 1: 2-stage coated 130 ° C. those diluted with 150 mesh gravure roll at 1 165 ° C after drying for 2 minutes
The mirror-like roll was used to perform surfacing at a pressing pressure of 2.5 kg / cm ² to obtain a leather-like sheet. In this surface layer has pores of about 500 / c ^{m 2} there them 40% of crosslinked structure permeable is 0.7 cc / cm ² / sec, and irritability without feeling luxury It had a feeling.

Comparative Example 1 Heat-foaming resin Heimlen X-30 was added to the base layer of Example 1.
40 (Dainichiseika Co., Ltd.) 100 parts pigment X-2070
30 parts of (Dainichi Seika Co., Ltd.) was added, and further 5 parts of ink prepared by diluting 50 parts of methyl ethyl ketone: water = 1: 1.
After applying one stage 5M gravure roll, the silver sheet with more black ink MT over 6701 (Dainichiseika): isopropyl alcohol: Echiruse B cellosolve = 2: 1: 2 at 150M gravure roll those diluted with 1 Step application 1
It was dried at 30 ° C. for 2 minutes. Chamfering was then performed with a mirror pressure roll at 165 ° C. under a pressing pressure of 2.5 kg / cm ² to obtain a leather-like sheet. Although this leather-like sheet had air permeability, it lacked in blackness and became more irritating, and was poor in luxury. This surface layer has about 600 pores / cm
² Yes There was no bridge structure at all.

Comparative Example 2 100 parts of CUT-7450NL (Dainichiseika Chemicals Co., Ltd.) of one-pack type ether / ester type composition was added to the base layer of Example 1.
Pigment Seika Seven BS-1710 Black (Dainichiseika Co., Ltd.) 15 parts, solvent dimethylformamide 40 parts ink 100 g / m ² by wet coating, 30 ° C
Was washed with warm water and dried. On this silver- coated sheet, black ink MT-6701 (Dainichi Seika): IPA: ethyl cellosol
The product diluted with 2: 1: 1 is applied in two steps with a 150M gravure roll, dried at 130 ° C for 2 minutes, and further 1
Chamfering was performed at a pressing pressure of 2.5 kg / cm ² with a mirror surface roll at 65 ° C. to obtain a leather-like sheet. This leather-like sheet was satisfactory in terms of blackness and high-grade feeling such as irritability, but did not have fine pores on the surface and was poor in air permeability.

[0026]

[Table 1]

As is clear from the results shown in Table 1, the leather-like sheets of the examples have good appearance such as irritability, luster, creases and wrinkles, a good texture, and a high air permeability. Understand.

[0028]

Leather-like sheet of the present invention according to the present invention has the following fine pore diameter 300 [mu] m 100 / cm ² or more to the silver surface layer,
Moreover, since a polyurethane fiber bridging structure is present in at least some of the fine pores, it is a leather-like sheet excellent in texture, gloss and creases, and good in irritability and air permeability.

[Brief description of drawings]

FIG. 1 is a schematic view of a representative cross section of a leather-like sheet of the present invention.

FIG. 2 is a schematic view of a representative surface of the leather-like sheet of the present invention.

[Explanation of symbols]

1: Polyurethane fiber bridging 2: Micropore 3: Polyurethane coating layer 4: Base layer

Front Page Continuation (72) Inventor Toyohashi Toyohashi, Furu-gun, Gifu 4330 Omotesa, Kuraray Plastics Co., Ltd. (56) References JP-A-5-93372 (JP, A) JP-A-4-300368 (JP, A) JP-A 1-246480 (JP, A) JP-A 64-85379 (JP, A) JP-A 47-5042 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) D06N 3/00-3/18

Claims (2)

(57) [Claims] 1. A leather-like sheet comprising a base layer composed of a fiber-entangled nonwoven fabric and an elastic body contained therein, and a urethane coating layer having a thickness of 10 to 100 μm formed on at least one surface thereof. The diameter of the polyurethane coating is 3
A leather-like sheet characterized in that it has 100 or less fine pores of 00 μm or less per cm ² , and that at least some of the fine pores have a bridge structure of polyurethane fibers. ^2. A non-woven fabric made of polyurethane fibers having a basis weight of 5 to 125 g / m ² is superposed on at least one surface of a fiber-entangled non-woven fabric and a base layer made of an elastic polymer contained therein, and the mixture is heated and pressed. A method for producing a leather-like sheet, which comprises fusing polyurethane fibers and laminating and integrating them with a base layer.