JP3142103B2 - Leather-like sheet excellent in flexibility and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is applicable to clothing with silver, various gloves, soft sports shoes, etc.
The present invention relates to a leather-like sheet having excellent drapability and moisture permeability and having a smooth and high-grade appearance similar to natural leather and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a leather-like sheet with silver having excellent flexibility and moisture permeability, a polymer mainly composed of an elastic polymer is provided on the surface of a fibrous base layer containing a porous elastic polymer. And a laminate in which a porous coating layer or a non-porous coating layer is laminated or a non-porous coating layer is further laminated on the surface of the porous coating layer. Examples of the method for obtaining the porous coating layer include a wet coagulation method in which a solution of an elastic polymer is treated with a non-solvent of the elastic polymer to solidify into a porous form, and a salt, starch, gelatin, or the like is easily extracted from the elastic polymer solution. After coating and drying a composition liquid containing water-soluble fine particles, or kneading the easily extractable fine particles into an elastic polymer to form a sheet, extracting and removing the fine particles to form a porous structure, dry foaming Is known. In addition, it is particularly preferable to form a polyurethane resin layer obtained by mixing a fine powder of a water-soluble natural polymer such as gelatin or starch on the surface of the wet microporous layer and dissolve and remove the water-soluble fine powder to form a porous coating layer. Kaihei 2-91279
Gazette, JP-A-2-169777, JP-A-2-3
No. 077987.

[0003]

There are various kinds of leather-like sheets which have been conventionally proposed, which are characterized by flexibility and moisture permeability, all of which have excellent flexibility, drapability and moisture permeability. However, it is insufficient for high-grade silver-applied clothing and various glove applications that require a high-grade appearance on the surface. That is, the method of providing a porous wet film as the surface layer requires a thick film if the surface smoothness is to be obtained only with the wet film, resulting in poor texture, and a non-finished layer as a finishing layer on the porous wet film. By providing a porous dry film, the surface layer becomes hard, and the balance with the base layer tends to be lost, resulting in a material without a sense of unity. On the other hand, a method of providing a nonporous film or a porous film by a dry surface method or the like can be formed with a relatively thin film, but lacks a sense of quality of the surface,
Insufficient flexibility and drapability for clothing and various gloves,
The moisture permeability was also insufficient. Also, a method of forming a polyurethane resin layer in which a fine powder of a water-soluble natural polymer is mixed on the surface of the wet microporous layer and dissolving and removing the water-soluble fine powder to form a porous coating layer, The thickness of the water-soluble natural polymer fine powder is large, and the pore size of the porous layer obtained by removing it is large, so that it is flexible and drapable for thin clothing and various gloves. Insufficiency and moisture permeability were also insufficient. The present invention solves the above problems, has excellent flexibility and drapability, and has a capacity of 4000 g / m ² · 24 h
An object of the present invention is to provide a leather-like sheet having the above-mentioned high moisture permeability and having a smooth and high-grade appearance similar to natural leather and a method for producing the same.

[0004]

Means for Solving the Problems The present inventors have focused on the structure of the surface layer and made intensive studies. As a result, specific particles were extracted on a surface porous thin film integrated with the base layer. It has been found that a leather-like sheet having the above-mentioned characteristics can be obtained by making the obtained porous dry film. That is, the present invention relates to a sheet-like article having a coating layer of an elastic polymer on the surface of a base layer containing an elastic polymer in a fiber assembly, wherein the coating layer is integrated with the base layer, and Observed thickness 10-4 with continuous pores of maximum pore diameter 1-30 μm
From a wet porous intermediate coating layer of 0 μm and a dry porous surface coating layer having a thickness of 20 to 100 μm and having pores having a maximum pore diameter of substantially 20 μm or less obtained by extracting and removing fine particles. It is a leather-like sheet having excellent flexibility characterized in that both layers contain a softening agent, and the production method thereof is as follows: (a) forming a sheet-like fiber aggregate; (B) a step of impregnating the fiber assembly with a composition liquid of an elastic polymer and coagulating to form a base layer containing the elastic polymer in the fiber assembly; (c) providing an elastic surface on the fiber assembly. A step of forming a wet porous intermediate coating layer having pores with a maximum pore diameter of 1 to 30 μm observed in cross section at a thickness of 10 to 40 μm integrated with the base layer and wet-solidified with a polymer composition liquid, d) On the release paper, the elastic polymer solution mixed with hot water extractable fine particles A step of applying a polymer composition solution, laminating and drying on the wet porous intermediate coating layer, and then releasing the release paper to form a dry film; (e) hot water extraction of the hot water extractable fine particles from the dry film; Thickness having continuous pores with a maximum pore diameter of 0.5 to 20 μm observed in the cross section
Denaturing into a dry porous surface coating layer of １００100 μm,
(f) A leather-like sheet having excellent flexibility is produced by combining at least the step of applying a softener to the wet porous intermediate coating layer and the dry porous surface coating layer.

[0005] As the fiber aggregate constituting the base layer of the present invention, a sheet-like material such as a woven fabric, a knitted fabric or a non-woven fabric made of long fibers or short fibers can be used. From the viewpoint of the above, it is preferable that at least one surface is raised. It is particularly preferable to use a nonwoven fabric as a fiber aggregate in terms of the ease of adjusting the thickness of the base layer, a soft texture similar to leather, and the like. May be laminated and integrated.

The fibers constituting the fiber assembly include ordinary fibers, for example, synthetic fibers such as polyester, polyamide, polyacrylonitrile, polyolefin, and polyvinyl alcohol, and synthetic fibers such as regenerated cellulose.
Natural fibers, or fibers of a special form, for example, ultra-fine fibers such as polyester and polyamide, and at least one component of a multi-component fiber composed of two or more resins having different solubility and degradability in a solvent or a decomposer, etc. It can be appropriately selected from ultrafine fiber bundle fibers or special porous fibers modified by decomposition and removal depending on the application. In view of the flexibility and drapability of the obtained sheet-like material, the single-fiber fineness of polyester, polyamide, or the like, particularly polyamide, is 0.1%.
Ultrafine fibers or ultrafine fiber bundle fibers having a denier of 1 to 0.0001 are preferable. Also, by lowering the drawing conditions of the fiber within a range that does not affect the fiber strength, a softer sheet-like material can be obtained.

[0007] These fibers are formed into a fabric such as a nonwoven fabric, a raised knitted woven fabric, or a laminated fabric of a nonwoven fabric and a woven fabric entangled by a needle punch or a high-speed fluid flow. In addition, when using the ultrafine fiber bundle fiber or the special porous fiber as the fiber aggregate constituting the base layer, it is difficult to form the fiber aggregate using the denatured fiber. It is preferable that a fiber aggregate is formed using the fibers, and the multicomponent fibers are transformed into ultrafine fiber bundle fibers or special porous fibers after impregnation with the elastic polymer. The weight of the fiber aggregate is not particularly limited, and may be appropriately selected depending on the intended final use field, and is usually selected from the range of 100 to 1000 g / m ² . When the fiber aggregate is a non-woven fabric, it is preferably 200 g / m ² or more from the viewpoint of processability such as impregnation treatment of an elastic polymer, which is necessary when manufacturing a thin material used for clothing or the like. Wet porous fibrous material is impregnated with an elastic polymer by impregnating an elastic polymer into a fiber assembly having a weight about twice the weight of the wet porous media, and a wet porous intermediate coating is formed by forming a wet porous intermediate coating layer on both surfaces and then dividing the thickness direction into two with a band knife. It is also possible to manufacture two base layers at one time. Prior to the polymer solution impregnation treatment, the surface of the fiber aggregate is subjected to a smoothing treatment by a conventionally known method such as hot pressing, if necessary. When the fiber constituting the fiber aggregate is a multi-component fiber with polyethylene as the sea component and polyester or polyamide as an ultra-fine island component, extremely excellent surface smoothness is obtained by welding the sea component polyethylene by hot pressing. This is particularly preferable because it can be used as a fiber assembly. When the fiber constituting the fiber aggregate is not a multicomponent fiber capable of dissolving and removing one component and transforming it into an ultrafine fiber, the impregnating elastic polymer is prevented from sticking to the fiber and hardening the hand. For this reason, it is preferable to cover the fiber surface with a temporary filling substance such as polyvinyl alcohol before impregnation with the elastic polymer.

The elastic polymer impregnated into the fiber aggregate or the elastic polymer provided as a thin coating layer on the surface thereof is, for example, polyurethane, acrylic polymer, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, etc. A polymer mainly composed of at least one kind of elastic polymer selected from the group of elastic polymers can be used. Polyurethane is particularly preferred in terms of texture, durability and the like. As the polyurethane, polymer diols having an average molecular weight of 500 to 2500, for example, polyester diols, polyether diols, polyester ether diols,
Polycaprolactone diol, polycarbonate-geo-
And at least one diol selected from the group consisting of an organic polyisocyanate such as an aromatic diisocyanate, an aromatic triisocyanate, an alicyclic diisocyanate, and an aliphatic diisocyanate having a cyclic group. And at least one organic polyisocyanate selected from the group of 4,4 ', 4 "-triisocyanate and a low molecular compound having at least two active hydrogen atoms as a chain extender. The thermoplastic polyurethanes obtained by the reaction have the following composition depending on the intended field of use of the leather-like sheet.
It can be appropriately selected from those satisfying various physical properties such as deterioration resistance, yellowing resistance and dyeability.

A polymer mainly composed of an elastic polymer is dissolved in a solvent, and if necessary, a conventionally known coagulation controlling agent, a coloring agent and the like are added to form a composition for impregnation. The impregnating composition liquid is impregnated into the fiber assembly, immersed in a non-solvent of the polymer, and solidified to be porous. As a method of coagulating the elastic polymer impregnated in the fiber aggregate, a method such as steam coagulation can be used in addition to a wet method. Solidification by a dry method is generally not used in the present invention because the texture becomes hard. When the fiber aggregate contains multi-component fibers that can be transformed into ultrafine fiber bundle fibers or special porous fibers by removing at least one component, the polymer is impregnated and coagulated, and then an appropriate solvent or decomposition is performed. Multi-component fibers are transformed into ultrafine fiber bundle fibers or special porous fibers by treating with an agent or the like.

The intermediate coating layer (skin layer) integrated with the base layer is an indispensable layer in order to obtain surface smoothness, flexibility, moisture permeability, and a good crease feeling. That is, it is located between the base layer and the dry porous surface coating layer, and has the functions of providing the above-mentioned characteristics and producing a desirable feeling of unity as a leather-like sheet. If there is no intermediate coating layer,
Due to the direct adhesion between the substrate layer and the surface coating layer, the unevenness of the bonding surface of the substrate layer affects the surface, so that sufficient smoothness cannot be obtained. The texture becomes worse and the creasing becomes worse. In order to impart the above characteristics to the porous intermediate coating layer, it is necessary to control its thickness and sponge state within appropriate ranges. The porous intermediate coating layer in the present invention is extremely thin and has a small pore size as compared with a thickness of several hundred μm which is frequently used as a conventional wet-solidified coating layer. That is, the thickness is 10 to 40 μm, preferably 15 to 30 μm.
m. If the thickness is less than 10 μm, sufficient surface smoothness cannot be obtained, and if it is more than 40 μm, the texture tends to be hard.

Further, as for the size of the pores of the intermediate coating layer, the maximum pore diameter of the pores of 90% or more of the pores observed in the cross section is 1 to 30 μm, preferably 1 to 10 μm. When the elastic polymer is wet-solidified, the pores are generally elongated in the thickness direction, and the maximum pore diameter tends to be 1 μm or more. Maximum pore size is 3
If the solidification is performed under the condition of 0 μm or more, it becomes difficult to form a film having a thickness of 10 to 40 μm as an intermediate coating layer.
These holes communicate not only with the inside of the skin layer but also with a part of the surface, and contribute to the improvement of moisture permeability and adhesion to the surface coating layer. In the present invention, the maximum pore diameter of the wet-membrane porous intermediate coating layer is defined as a cross-section when the longitudinal section of the coating layer is observed at a magnification of at least 1000 times, preferably 3000 times with a scanning electron microscope or the like. The maximum width (width corresponding to the maximum diameter) of the vertically long pores to be formed.

The method of forming the intermediate coating layer is to impregnate the fiber assembly with the polymer composition liquid, form a coating film of the elastic polymer composition liquid to be the intermediate coating layer on the surface prior to wet coagulation, and wet coagulate. To form an intermediate coating layer by impregnating the fiber assembly with the polymer composition liquid and coagulating it, then applying the polymer composition liquid by a bar coat or knife coat and wet coagulation to form an intermediate coating layer. However, the former is preferred from the viewpoint of the integrity of the intermediate coating layer and the base layer and the cost. In the former case, the method of forming a coating film of the polymer composition liquid is such that when the elastic polymer liquid impregnated in the fiber assembly is drained, the distance relationship between the draining knife and the fiber assembly is adjusted to adjust the fiber assembly. A method of forming a coating layer of an impregnating composition liquid on the surface, impregnating the fiber assembly with the elastic polymer composition liquid, draining the liquid, and then applying the elastic polymer composition liquid for the intermediate coating layer with a bar coat, knife coat, or the like. Although there are coating methods and the like, it is preferable to form the intermediate coating layer at the same time as the drainage of the impregnating liquid from the viewpoint of easy control of the thickness of the coating film and simplicity of the process. The elastic polymer of the intermediate coating layer is preferably polyurethane as described above, and the type thereof can be selected as long as the compatibility with the polyurethane of the base layer is good. That is, in consideration of the overall texture, peel strength, etc., the polyurethane used as the coating liquid may be the same type of polyurethane as the polyurethane for the base layer or a different type of polyurethane. May be the same or different. Usually, the concentration of the polyurethane solution used for coating is the same as or higher than the concentration of polyurethane used for impregnation. The sponge state of the intermediate coating layer can be adjusted by appropriately selecting the coagulation conditions such as the concentration of the urethane composition liquid to be applied, the type and amount of the additive, the composition of the coagulation liquid, and the temperature. Increasing the concentration or viscosity or increasing the temperature of the coagulation bath or the concentration of the solvent tends to decrease the maximum diameter of the pores. Maximum pore size is 1-3 depending on the type of polyurethane used
Select the condition to be 0 μm.

[0013] The porous surface coating layer is the most important part of the present invention. That is, flexibility, drapability, moisture permeability, and high-grade appearance are largely determined by the structure of the surface coating layer. Since the porous layer formed by the wet method has insufficient physical properties such as strength as a surface layer, the surface coating layer is formed by a dry method in the present invention. Usually, as a method for obtaining a porous dry film, a method using a foaming agent, a method for foaming by reaction, a method using a mechanically foamed coating solution,
There is a method using water-extractable fine particles, but the former three methods tend to become independent bubbles in the dry membrane and the pores are not continuous, so there is no effect of increasing the moisture permeability. In the present invention, a method utilizing the extractable particles is studied, and a condition which has not been used before is adopted, and the thickness is 20 to 100 μm, preferably 30 to 80 μm.
m and a novel structure in which pores larger than the maximum pore diameter of 20 μm are substantially absent, thereby obtaining a leather-like sheet having the above characteristics. The maximum pore size is
Preferably, the maximum pore diameter is 0.2 μm, which can be confirmed to be pores on an electron micrograph taken at a magnification of 3000 times.
80% by volume of pores (diameter 0.6mm on the photograph) or more
The above is 10 μm or less, 30% or more is 2 μm or less, more preferably 90% or more is 10 μm or less, and 50% or more is 2 μm or less. The average of the maximum pore diameter is preferably in the range of 1 to 5 μm, and more preferably in the range of 1 to 3 μm. In the present invention, the maximum pore diameter of the dry membrane porous surface coating layer is the maximum diameter of pores observed in the cross section when the vertical section of the coating layer is observed at least 3000 times with a scanning electron microscope or the like. Say. Specifically, 3
In a region of at least 600 cm ² (corresponding to about 6700 μm ² ) on an electron micrograph taken at a magnification of 000 times, a diameter of 0.6 mm (diameter of 0.
6 mm, 30 mm
And 60 mm circles (2 μm, 10 μm and 2 μm, respectively)
(Equivalent to 0 μm) are superimposed on each other, and the range of the maximum diameter is determined based on whether or not the whole pores fit in each circle. The number of pores corresponding to each maximum diameter range is counted, and the ratio of each quantity to the total number of pores is determined. In addition, many of the pores observed in the vertical section of the dry membrane porous surface layer of the present invention are cross sections or oblique sections of continuous tunnel-shaped pores, and the ratio of the major axis to the minor axis is 2 or less. And elliptical shapes are deformed. As the shape of the pores observed in the cross section, there may be a case where a long and narrow pore shape in which the ratio of the major axis to the minor axis is 2 or more is observed in a state close to the longitudinal section of the continuous tunnel. The maximum diameter is the maximum width in the minor axis direction.

The porosity of the dry membrane porous surface coating layer is 20
It is preferably in the range of 70 to 70%, and more preferably 30 to 70%.
Preferably it is 50%. Depending on the type and physical properties of the elastic body constituting the dry-membrane porous layer, the porosity of the dry-membrane porous surface coating layer increases, but the softness tends to be poor in mechanical strength. It tends to have a texture with a large rebound.

[0015] The main conditions for creating excellent flexibility, moisture permeability, surface strength, favorable touch, and surface feel by the surface forming method using extractable particles are 1) the type of the elastic polymer to be used and the lamination conditions 2) use Type of extractable particles to be used and mixing conditions 3) Coating treatment conditions are decisive.

1) As the elastic polymer to be used, various applications can be applied as described in the resin conditions for impregnating the base layer, but it is preferable to use polyurethane as a main component from the viewpoint of feeling and durability. As the polyurethane, the same polyurethane as that used for the impregnation or the intermediate coating layer can be used. The composition of the polyurethane depends on the intended field of use of the leather-like sheet, and the texture, abrasion resistance, and deterioration resistance. It can be appropriately selected from those satisfying various physical properties such as resistance, yellowing resistance, and dyeability. The polyurethane for the base layer or the intermediate coating layer needs to be mainly suitable for wet coagulation type, whereas the polyurethane for the surface coating layer is a dry film type and does not require wet coagulation, but has abrasion resistance. Durability is mainly required.

The polyurethane used in the dry surface method in which a polyurethane solution is coated on release paper and adhered to the substrate layer is usually one-pack polyurethane used for the surface and the intermediate layer, and polyurethane used for the adhesive. There are two types of two-component adhesives used, which are cross-linked and cured after treatment. Polyurethane for adhesives has an effect of increasing the adhesive strength to the base layer and the film strength of the surface layer. The polyurethane for the surface coating layer used in the present invention is a one-pack polyurethane for the skin and the intermediate layer, and a two-pack polyurethane is not used. This is to prevent the cross-linking curing from hindering the extractability of the particles and to prevent the feeling of the entire sheet-like material including the substrate layer from being deteriorated. Note that the release paper in the present invention is a paper or film that has been conventionally used in the production of artificial leather or the like, which is provided with a release property by a release resin or the like, and has an uneven pattern or a smooth surface on the surface. Is a general term for a releasable sheet having

These resins for the surface coating layer are dissolved in a solvent, mixed with a colorant, extractable particles and the like, and applied in one or more layers. In order to obtain the composition, it is preferable to divide the composition into multiple layers and apply them with different composition liquids. That is, the skin layer to be first applied to the release sheet is made of polyurethane having a high modulus or a nitrocellulose resin or an amino acid polymer as long as there is no problem in adhesiveness in order to obtain a favorable touch and surface strength. In the intermediate layer between the surface layer and the next coating layer, a polyurethane having a low modulus is selected to obtain a good feeling and moisture permeability, and a large amount of extractable particles are mixed in a range where there is no problem in the film strength. Further, in the adhesive layer portion in contact with the intermediate coating layer, the adhesion to the intermediate coating layer is emphasized, the amount of extractable particles mixed is reduced, and the viscosity is set so as to easily penetrate into the intermediate coating layer. Further, the coating amount of each layer is set to be larger for the intermediate layer, and the layers and the skin layers in contact with the intermediate coating layer are set to be slightly smaller. The coloring agent contains the same or different pigments or dyes in each layer in consideration of the color developing properties.

2) The extractable particles used must be finely pulverized to a required particle size and must be easily dissolved in water or hot water. For example, sodium chloride, sodium sulfate, Inorganic compounds such as gelatin, natural organic substances such as sugar, polyvinyl alcohol, and a copolymer of ammonia-modified maleic anhydride and isobutylene (for example,
Organic compounds such as Kuraray's Isoban (trade name) can be mentioned, but ammonia-modified maleic anhydride-isobutylene copolymer is most suitable from the viewpoint of particle solubility, fineness, and handling. is there. That is, sodium chloride,
Inorganic compounds such as sodium sulfate and organic compounds such as polyvinyl alcohol such as sugar cannot be sufficiently formed into fine particles, and their solubility is insufficient.Gelatin has good solubility but has high hygroscopicity. It is difficult to make fine particles and the handling is poor.

Further, it is important that a part of the extractable fine particles used in the present invention is dissolved in a solvent of the elastic polymer, and it is important that the extractable fine particles are not uniformly mixed with the elastic polymer solution in a solution state and undergo phase separation. is there. That is, the continuous pores and pore size distribution of the dry membrane porous surface layer of the present invention cannot be obtained by simply mixing and extracting fine particles that are not dissolved in the elastic polymer solvent into the elastic polymer solution. When a part of the fine particles are dissolved in the solvent of the elastic polymer, the fine particles become smaller, and the sharp corners at the time of pulverization become rounded. Further, it is considered that the presence of the solution of the dissolved fine particles in a layer-separated state from the elastic polymer solution greatly contributes to the formation of fine tunnel-shaped pores. The ratio of the portion of the extractable fine particles dissolved in the elastic polymer in the solvent varies depending on the concentration and viscosity of the elastic polymer solution, the particle size of the extractable fine particles, and is not necessarily limited. 10 parts of hot water extractable fine particles to 9 parts
The dissolved content after stirring at 0 ° C. for 30 minutes is about 5 to 40% by weight. If the dissolved portion is small, fine pores are not sufficiently formed, and if the dissolved portion is too large, the pores are too fine and the texture tends to be hard. The extractable fine particles need not necessarily be one kind, and two or more kinds can be used in combination. In addition, if it is possible to sufficiently form fine particles, extractable fine particles that do not dissolve in the solution of the elastic polymer can be used in combination, and instead of the extractable fine particles that partially dissolve in the solvent, the elastic polymer can be used. However, it can be used in combination with an extractable resin which dissolves in the above solution but does not mix uniformly with the elastic polymer solution and has high affinity with the extractable fine particles.

The solubility of the copolymer of maleic anhydride and isobutylene in water and the solubility in organic solvents such as dimethylformamide can be controlled by changing the degree of modification with ammonia.

The suitable average particle size of the extractable fine particles is as follows:
2-20 μm depending on the pore size of the porous layer after extraction
m, preferably 5 to 10 μm. If it is less than 2 μm, the particles tend to aggregate and the extractability is poor. If it is more than 20 μm, the pores become too large, the film strength is reduced and the surface smoothness is poor. The particle size distribution is about 1 to 50 μm,
It is preferable that the 2 to 20 μm portion is 80% or more. When using extractable fine particles that are not partially soluble in the solvent of the elastic polymer, the fine particle diameter is not reduced after mixing with the elastic polymer solution, so it is necessary to use fine particles having a smaller particle size. It is preferable to use fine particles having as few sharp angles as possible when pulverized. If the extractable fine particles have many sharp corners, the porous layer after extraction tends to be brittle and have poor mechanical strength.

The amount of the extractable fine particles mixed into the resin of the surface coating layer is as follows.
Parts by weight, preferably 0 to 20 parts by weight;
100 to 300 parts by weight, preferably 1 to 100 parts by weight
50 to 250 parts by weight, the layer in contact with the skin layer is resin 10
0 to 50 parts by weight, preferably 0 to 20 parts by weight with respect to 0 parts by weight
Parts by weight. If the amount of the extractable fine particles is more than 50 parts by weight in the skin layer, the pattern of the release sheet on the surface is not clearly transferred, and the fine particles easily adhere to the release sheet. If the mixing amount of the extractable fine particles in the intermediate layer is less than 100 parts by weight, a sufficient porous structure cannot be obtained, and if it is more than 300 parts by weight, pores are united to form huge voids and the film strength is reduced. If the amount of the extractable fine particles in the layer in contact with the intermediate coating layer is 50 parts by weight or more, the area of adhesion to the intermediate coating layer after extraction is reduced, and the adhesive strength is reduced.

Incorporation of the extractable fine particles into the surface layer resin requires sufficient agitation so as not to cause poor dispersion and filtration of the aggregated fine particles. In the present invention, since the extractable fine particles are partially dissolved, the corners of the fine particles are rounded, and the fine particles are further formed into fine particles, the amount of the fine particles is equal to or more than three times the solid content of the resin in the intermediate layer. Even so, a porous coating layer having excellent mechanical strength can be obtained.

3) In the coating treatment, the respective composition liquids are applied on the release sheet in the order of the skin layer, the intermediate layer, and the adhesive layer (the layer in contact with the skin), and finally, the composition layer is bonded to the base layer. However, the important points here are the drying conditions of each coating liquid and the bonding pressure conditions. That is, the extractable fine particles are in contact with each other in the thickness direction of the surface coating layer to form continuous pores after extraction, to make the grain pattern on the skin surface clear, and to coat the intermediate coating layer. In order to effectively penetrate the liquid and increase the adhesive strength, the drying conditions and the bonding pressure conditions of each coating liquid are adjusted according to the brand of treatment. If the drying conditions after applying each liquid are too strong, the grain on the skin surface will be sharp, but the extractable fine particles mixed in each layer will be fixed as they are and will not move even if pressure is applied during bonding, and the extractable fine particles will contact each other. Because it is difficult to be in a state that it is difficult to obtain, not only does not become continuous pores after extraction and sufficient moisture permeability and texture cannot be obtained,
Further, the coating liquid does not sufficiently penetrate into the intermediate coating layer, and the adhesive strength between the surface coating layer and the intermediate coating layer is reduced. Conversely, if the drying conditions are too weak, the extractable fine particles in the intermediate layer move in large amounts to the skin surface, and the grain on the skin surface becomes unclear. Also, if the bonding pressure is too low, the movement of extractable fine particles in each layer is small, and the penetration of the coating liquid into the intermediate coating layer is insufficient and sufficient moisture permeability, texture,
No adhesive power. Conversely, if the pressure is too high, the adhesive strength will increase, but excessive penetration will occur partially or extractable fine particles will collect on the skin surface, causing poor surface smoothness and unclear grain. After the surface is formed under appropriate conditions and wound up, it is necessary to fix the surface layer sufficiently.
It is preferable to ripen for about a day.

As a method for extracting the fine particles, the fine particles can be treated with a usual dyeing machine. That is, the Dip-Nip method,
Any of the following methods can be used: the Winning method, the Circular method, etc., but the Winning method and the Circular method, which also provide a relaxing effect of the base layer, are more suitable. As the processing conditions, most of the fine particles are extracted at a water temperature of 60 ° C. to 100 ° C. and a processing time of about 40 to 100 minutes, and the substrate layer is sufficiently relaxed. By the extraction and relaxation treatment of the fine particles, the surface coating layer is transformed into a dry membrane porous surface coating layer having continuous pores having a maximum pore diameter of substantially 20 μm or less and an average of 1 to 5 μm. When the extractable fine particles are not partially dissolved in the solution of the elastic polymer and gelatin fine particles having a large particle diameter are used, even if the gelatin particles are dissolved and removed, the surface coating layer has an extremely fine particle as in the present invention. No pores are obtained and the maximum diameter is often larger than the average diameter of the gelatin particles used.

The sheet-like material after the extraction treatment is subjected to a combination of an additional coloring treatment, a calendar treatment, and the like for giving a high-grade feeling to the surface, if necessary. Further, the sheet material of the present invention is subjected to a softener treatment in order to impart excellent flexibility. That is, the sheet-like material of the present invention obtained as described above is a soft leather-like sheet-like material. A high-quality leather-like sheet with excellent softness that has a unique texture and drape that improves sliding and has a softening agent in a porous cell. Is obtained.

For the softener treatment, the Dip-Nip method is sufficient. As the treating agent, ordinary softening agents such as aminosilicone, ethylene glycol and various oils can be applied, but not only the softening effect but also the permeability, the deterioration of resin and fiber, the various fastnesses, etc. Make choices with consideration. After the softener treatment, it is preferable to use a mechanical kneading treatment in order to enhance the effect of applying the softener.

The skeleton of the present invention has been described above. By combining various conditions, a high-quality leather-like sheet suitable for various uses can be obtained. The leather-like sheet obtained by the present invention is a leather-like sheet having excellent flexibility, drapability, high moisture permeability, and high-grade surface feeling, and is used for clothing, gloves, bags, Bags, men's and women's shoes, sports shoes,
Suitable for interior use.

[0030]

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

Example 1 A multi-component fiber having a dispersing component of 6-nylon kneaded with a black pigment and polyethylene as a dispersing medium component (the component ratio is 1: 1 by weight) has a basis weight of 300 g / m ² . The entangled nonwoven fabric is impregnated with a 13% dimethylformamide (DMF) solution of polyurethane containing polyethylene adipate and polyethylene glycol as polymer diol components containing a black colorant, and both sides are drained with a doctor knife. 25% D
Solidified in MF aqueous solution. After drying the sheet, the polyethylene in the multi-component fiber is dissolved and removed with hot toluene, and the polyurethane is in a porous state in a non-woven fabric of a bundle of ultra-fine fibers in which about 300 ultra-fine fibers of 0.007 denier are bundled. A sheet was obtained in which a porous polyurethane skin layer having a thickness of about 30 μm and a maximum pore diameter of 1 to 10 μm was formed on both sides of the contained base layer. The sheet was divided into two slices in the thickness direction, and three layers of polyurethane resin were applied to one surface by a dry surface method. That is, a silicone-modified ether-based polyurethane (UST-125C, manufactured by Dainippon Ink Co., Ltd.) was used as a skin layer on a release sheet having a grain pattern.
To 100 parts of a 25% dimethylformamide solution of P), add D
A copolymer of maleic anhydride and isobutylene modified with ammonia and having 20% by weight of MF dissolved therein was mixed with 7 parts of fine particles having an average particle diameter of 8 μm (hereinafter referred to as “isoban fine particles”) at a ratio of 10 parts of black pigment, and sufficiently stirred. The resulting solution was coated at 70 g / m ^{2 and} dried at 80 ° C. for 1 minute, and the same isovan microparticles were added to 100 parts of a 25% dimethylformamide solution of ether-based polyurethane (ME8105, manufactured by Dainichi Seika Co., Ltd.).
0 parts, a black pigment was mixed in a ratio of 20 parts, and a solution that was sufficiently stirred was applied at 120 g / m ^{2 and} dried at 80 ° C. for 2 minutes. Then, an ether polyurethane (manufactured by Dainichi Seika Co., ME8105) in a 25% dimethylformamide solution (100 parts), the same isovan fine particles mixed at a solid content ratio of 10 parts and a well stirred solution of 80 g / m ^{2 was} applied, and the solution was applied on the intermediate coating layer with a clearance roll. 100 after combining
Dried at 2 ° C. for 2 minutes. After aging for another 2 days, the release sheet was peeled off, and the sheet was cured with a circular jet dyeing machine.
The mixture was relaxed at 60 ° C. for 60 minutes to dissolve and remove the isoban fine particles and dried. Next, as a softening treatment, 2Dip-2Nip treatment with a 25% aqueous solution of a silicon softening agent (a mixture of Nikka Silicon / Lastex, manufactured by Nikka Co., Ltd.)
After drying, it was further rubbed to obtain a leather-like sheet.

The longitudinal section of the dry porous coating layer of the sheet was photographed at a magnification of 3000 times with a scanning electron microscope.
When the thickness and the size of the pores appearing in the cross section were measured, the thickness was 70 μm, no pores having a maximum pore diameter of 20 μm or more were observed, and the maximum pore diameter was 0.2 μm per 7000 μm ² in cross section.
The total number of pores having a diameter of 2 μm or less is 436, and the number of pores having a diameter of 10 μm or less is 428 (98%).
Five (72%), the average of which was 1.5 μm. The obtained sheet-like material had a particularly good texture, a luxurious surface, and had a rich drape property and high moisture permeability, and was very preferable as a raw material for clothing.

Comparative Example 1 In Example 1, finishing was performed only by rubbing treatment without performing softener treatment, and a leather-like sheet was obtained. Although the obtained sheet-like material has a high-grade appearance on the surface, the sheet obtained in Example 1 was used.
The raw material had a soft touch and drape property on the surface slightly less than that of the sheet-like material.

Comparative Examples 2 to 4 A leather-like sheet was obtained by the same process as in Example 1 except that the thickness of the intermediate coating layer was changed to 0 μm (not applied), 5 μm and 70 μm. Finished things. The resulting sheet-like material had an intermediate coating layer of 0 μm or 5 μm.
In the case of μm, the texture, drapability, touch, etc. were good and had high moisture permeability, but the thickness of the dry porous surface coating layer was 50 μm and 65 μm, respectively. The raw material was poor in surface smoothness and had folds in the width direction as compared with the sheet-like material obtained in Example 1. When the intermediate coating layer was 70 μm, the surface smoothness was good, but the maximum pore diameter of the pores of the intermediate coating layer was as large as 1 to 60 μm, the texture was hard, the drapability was lacking, and the luxury was lacking. Met.

Comparative Example-5 A sheet was finished under the same conditions as in Example 1, except that gelatin fine particles having an average particle size of 15 μm were used instead of the isovan fine particles. When the cross section of the surface coating layer of the obtained sheet-like material is observed with a microscope, the thickness is 85 μm, the maximum diameter of the pores is in the range of 2 to 30 μm, the pores of 10 μm or less are 40%, and the pores of 2 μm or less are 8%. Met. Although this leather-like sheet was soft, it lacked drape properties and a moist touch, and lacked a sense of quality.

Comparative Example -6 A base layer having the same structure as in Example 1 except that the thickness of the intermediate coating layer was 5 μm was used, and a surface coating layer was applied to the surface thereof by a wet method. That is, an ether polyurethane having a 100% modulus of 30 kg / cm ² was used as a coating liquid, and a 13% DMF solution was applied to the surface of the 350 g / m ² intermediate coating layer and solidified with water at 25 ° C. I let it. An 8% ether-polyurethane (isopropyl alcohol-toluene solvent) solution containing a black pigment was applied twice on the surface of the sheet with a 150-mesh, and then embossed with a jumpy sieve. The same softening treatment as that described above was carried out to obtain a leather-like sheet. The obtained sheet-like material had a surface wet porous layer having a thickness of 70 μm and a maximum pore diameter of pores of 10 to 60 μm.
As compared with the sheet-like material obtained in Example 1, the raw material had a hard texture, lacked smoothness of the surface, lacked a sense of quality, and had low moisture permeability.

COMPARATIVE EXAMPLE-7 The base layer without the intermediate coating layer of Comparative Example-2 was used, and a porous dry film layer having moisture permeability was provided on the surface thereof.
That is, a solution of a moisture-permeable polyurethane (Himlen X-3038, manufactured by Dainichi Seika Co., Ltd.) 100 on the release sheet.
Parts, black pigment 20 parts, methyl ethyl ketone 18 parts, toluene 18 parts, water 50 parts, Rezamin X (trade name: manufactured by Dainichi Seika Co., Ltd.) 2 parts as a crosslinking agent, Rezamin UM-317
(Trade name: manufactured by Dainichi Seika Co., Ltd.)
g / m ^{2 was} applied and dried at 80 ° C. for 2 minutes, then laminated on the surface of the base layer, and further heated at 130 ° C. for 2 minutes to form a surface. Thereafter, the same softening treatment as in Example 1 was performed to finish a leather-like sheet. When the surface coating layer of this sheet was observed under a microscope, the thickness was 72 μm, and the maximum pore diameter was 5 to 20 μm.
m, and the number was small, and the number of communicating pores was small. The obtained sheet-like material had a slightly harder surface compared to the sheet-like material obtained in Example 1.
The raw material lacked a natural feeling of wrinkles.

Comparative Example-8 A leather-like sheet was prepared by performing the same treatment as in Example 1 except that the same two-component polyurethane was used for the adhesive layer on the dry-formed surface using the same base layer as in Example-1. Finished into a shape. That is, 100 parts of an ether-based polyurethane (UD8310, manufactured by Dainichi Seika Co., Ltd.), 30 parts of dimethylformamide, 20 parts of methyl ethyl ketone, 12 parts of a crosslinking agent (NE crosslinked agent, manufactured by Dainichi Seika Co., Ltd.) as an adhesive layer, A solution (80 g / m ² ) was mixed with 8 parts of an agent (UD-103, manufactured by Dainichi Seika Co., Ltd.) and 30 parts of isoban having an average particle size of 8 μm, and the mixture was sufficiently stirred. The obtained sheet-like material had a poor texture and touch and was very low in moisture permeability as compared with the sheet-like material obtained in Example 1.

Example 2 A basis weight of 520 g / multicomponent fiber comprising polyethylene terephthalate as a dispersion component (average single fineness: 0.003 denier) and polyethylene as a dispersion medium component (weight ratio: 1: 1)
the entangled nonwoven m ^2, polyethylene adipate containing blue pigment - DOO / polyethylene glycol - 18% dimethylformamide (DMF) Le copolymer-based polyurethane solution was impregnated with,
40 g / m ² of the same solution was knife-coated on the surface to obtain 2
After coagulation in a 5% DMF aqueous solution, the polyethylene was dissolved and removed to obtain a base layer having a porous layer (intermediate layer) on the surface. This base layer contains polyurethane in a porous state in a nonwoven fabric of ultrafine fiber bundle-like fibers, and has an average thickness of 20 μm on its surface.
The sheet was formed with a porous polyurethane skin layer having a maximum pore size of 1 to 15 μm. Three layers of polyurethane resin were applied to the surface of the base layer sheet by a dry surface method. That is, an ether polyurethane (ME8115, manufactured by Dainichi Seika Co., Ltd.) 25 as a skin layer on the release sheet.
A solution obtained by mixing 70 parts / solution of 100 parts of a white pigment at a ratio of 20 parts by weight and thoroughly stirring was applied at 70 g / m ^{2 and} dried at 80 ° C. for 1 minute. ME8105) 100 parts of a 25% solution was mixed with 50 parts of the soban fine particles of Example 1 and 20 parts of a white pigment, and a well-stirred liquid was applied at 150 g / m ^{2 and} dried at 80 ° C. for 2 minutes. The same isovan microparticles were mixed at a ratio of 6 parts in 100 parts of a 25% solution of an ether-based polyurethane (manufactured by Dainichi Seika Co., Ltd., ME8105) and a well-stirred solution was applied at 80 g / m ² to form a base layer and a clearance slot. Then, the resultant was dried at 100 ° C. for 2 minutes. Two days after aging, the sheet from which the release sheet was peeled was relaxed at a temperature of 100 ° C. for 60 minutes using a circular jet dyeing machine and dried. Next, a slimming agent (U-981, manufactured by Seiko Chemical Co., Ltd.) was applied by gravure coating on one step of 100 mesh, and then subjected to the same softening treatment as in Example 1 to finish a leather-like sheet. Was.

A vertical section of the dry porous coating layer of the sheet was photographed at a magnification of 3000 times with a scanning electron microscope.
When the thickness and the size of the pores appearing in the cross section were measured, the thickness was 75 μm, no pores with a maximum pore diameter of 20 μm or more were observed, and the maximum pore diameter per cross-sectional area of 7000 μm ² was 0.
The total number of pores of 2 μm or more is 505, of which 478 are pores of 10 μm or less (94%) and 3 are pores of 2 μm or less.
99 (79%) had an average of 1.7 μm.
The resulting sheet-like material has a soft, stiff texture, a smooth surface and a slimy touch, and has both a sufficient surface appearance and high moisture permeability. It was an appropriate material for high-grade raw materials. Table 1 shows the evaluation results of the leather-like sheet materials obtained in each of Examples and Comparative Examples.

[0041]

[Table 1]

Method for measuring physical properties Moisture permeability JIS L1099-A1 Taber wear JIS L1096-6.17.3 Flexibility (FLEXO) JIS K6545 The porosity of a surface coating layer is the area ratio of pores observed in a cross section. expressed.

Symbols in the table (sensory test) ：: Extremely good ○: Excellent △: Slightly poor ×: Poor (Taber wear) A: No surface damage B: Small surface damage C: During surface damage D: Large surface damage E : Exposed base layer (flexibility) A: No surface cracking B: Small surface cracking C: Medium surface cracking D: Large surface cracking E: Perforated base layer

[0044]

The leather-like sheet of the present invention is a leather-like sheet having high moisture permeability, excellent flexibility, drapability, and a smooth and high-grade appearance similar to natural leather. It is suitably used for high-grade silver clothing, various gloves, soft sports shoes, and the like.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI D06N 3/14 D06N 3/14 // C08L 75:04 (58) Investigated field (Int.Cl. ⁷ , DB name) D06N 3 / 00-3/18 B32B 5/18 B32B 27/40 C08J 9/26 C08L 75:04

Claims (2)

(57) [Claims] 1. A sheet-like material having a coating layer of an elastic polymer on the surface of a base layer containing an elastic polymer in a fiber assembly, wherein the coating layer is integrated with the base layer and has a longitudinal section. A wet porous intermediate coating layer having a thickness of 10 to 40 μm having continuous pores having a maximum pore diameter of 1 to 30 μm and a continuous pore having a maximum pore diameter of 20 μm or less obtained by extracting and removing fine particles and having a maximum cross section of substantially 20 μm. 20 to 100 thickness with pores
A leather-like sheet having excellent flexibility, comprising two layers of a dry porous surface coating layer having a thickness of .mu.m and both layers containing a softener. 2. A step of (a) forming a sheet-like fiber assembly, and (b) impregnating the fiber assembly with a composition solution of an elastic polymer and coagulating the fiber assembly to form a substrate containing the elastic polymer in the fiber assembly. Forming a layer, (c) applying a composition solution of an elastic polymer to the surface of the fiber assembly, wet-solidifying and applying a thickness of 10 to be integrated with the base layer.
Forming a wet porous intermediate coating layer having pores with a maximum pore diameter of 1 to 30 μm observed in cross section at ４０40 μm, (d)
An elastic polymer solution containing an elastic polymer solution mixed with hot water extractable fine particles is coated on a release paper, laminated and dried on the wet porous intermediate coating layer, and then the release paper is peeled off to form a dry film. Step, (e) Maximum pore size 0.5 to 20 μm observed in cross section by extracting the hot water extractable fine particles from the dry membrane with hot water
m of a dry porous surface coating layer having a thickness of 20 to 100 μm having continuous pores of m, and (f) applying a softener to at least the wet porous intermediate coating layer and the dry porous surface coating layer. A method for producing a leather-like sheet having excellent flexibility, which is characterized by being combined.