JPH0411669B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Technical Field of the Invention The present invention relates to a method for producing a leather-like sheet material with improved surface gloss. More specifically, the present invention relates to a method for producing a leather-like sheet material that has a calm, deep surface luster similar to the surface of natural leather and gives a profound feeling.

B. Prior art and its problems Conventionally, the surface of a leather-like sheet product is coated with a coloring agent, a resin composition is coated thereon to adjust the surface gloss, and if necessary, the surface is embossed. The finishing touches are being made. However, by adjusting the surface condition by embossing or by adjusting and applying a resin composition, it is possible to achieve a surface that has a calm and deep luster similar to the surface of natural leather, and a heavy leather-like feel. It is still insufficient to obtain sheet products.

In particular, when a thick non-porous finishing layer is applied to the surface, or when the surface is colored by dyeing, the surface is highly reflective and gives a light and flimsy feel, which is not a desirable appearance characteristic. As a result of intensive study to improve this conventional surface condition,
It has been found that the above-mentioned drawbacks can be easily improved by low-temperature plasma treatment.

C. Object of the present invention The object of the present invention is to improve the surface of a leather-like sheet material having a coating layer of a polymer mainly composed of an elastic polymer, and to improve the surface of a leather-like sheet material, which has a matte tone similar to natural leather.
To provide a leather-like sheet material having deep surface gloss and color tone and giving a solid appearance.

D Structure of the present invention That is, the present invention provides a non-porous coating layer and/or a porous coating layer made of a polymer mainly composed of an elastic polymer on the surface of a porous base layer in which an elastic polymer is contained in a fiber entangled body. The surface of the leather-like sheet material, whose outermost surface coating layer contains inorganic fine particles, is subjected to low-temperature plasma etching treatment to make the surface of the leather-like sheet material uneven, thereby increasing the luster when dyed. and improves color tone.

The leather-like sheet material used in the present invention is produced by providing a coating layer of a polymer mainly composed of an elastic polymer on the surface of a porous base layer in which an elastic polymer is contained in a fiber entangled body, and providing a colored finish and, if necessary, a coating layer of a polymer mainly composed of an elastic polymer. It is a leather-like sheet material that has been embossed.

The porous base layer constituting the leather-like sheet material of the present invention is a fiber entanglement made using synthetic fibers such as polyester fibers, nylon fibers, and polyacrylic fibers, recycled fibers such as rayon, and cellulose acetate, or natural fibers. However, it is preferable to use modified fibers in order to obtain a flexible base layer with excellent drapability. As a modified fiber,
Multi-component fibers consisting of at least two types of polymers with different physical or chemical properties are used as raw materials, and after this fiber is made into an entangled nonwoven fabric, chemical or physical treatment is performed before or after incorporating resin. Alternatively, the fiber morphology is modified by mechanical treatment,
It can be obtained by modifying fine fibers into fiber bundles or special porous fibers. Examples of raw materials for multicomponent fibers include 6-nylon, 66-nylon, 6,
10-Polyamides such as nylon, polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polypropylene, and polybutene, acrylonitonyl polymers,
Spinnable polymers such as polyvinyl alcohol, polyvinyl chloride, styrenic polymers, cellulose derivatives, regenerated cellulose, etc. are used. When obtaining special fibers by extraction processing, the fiber component used, that is, the oil residue component, must be a spinnable polymer, but even if the extracted fiber component is a polymer that is non-spinnable by itself. good. At least two types of polymers having different physical or chemical properties from among these spinnable polymers or spinnable polymers and non-spinnable polymers are combined and spun. In this case, the fiber morphology is observed as a so-called sea-island fiber in which at least one type of polymer is dispersed as a micro cross section and at least one other type of polymer is dispersed as a dispersion medium component in the cross section of the fiber, or At least one type of polymer needs to be a so-called bonded fiber, which is observed to be regularly or irregularly arranged with other polymers. However, adhesive fibers obtained by spinning fine fibers and binding them with a glue can also be used as a raw material for obtaining the leather sheet product of the present invention. Such multicomponent fibers are subjected to treatments such as stretching, crimping, and cutting as necessary. Then, this multicomponent fiber is made into a fiber laminate, which is made into a fiber-entangled nonwoven fabric by methods such as needle punching and fluid jetting, and before it is impregnated with resin,
Alternatively, after containing a resin, the multicomponent fiber is chemically, physically or mechanically treated to form a knitted special fiber. That is, in the case of sea-island fibers, the dispersion medium component (or sea component) is treated with a solvent to dissolve and remove it, and the dispersion component (or island component) is made into independent fine fibers, thereby obtaining a fiber bundle made of fine fibers. In the case of bonded fibers, either of the components may be treated with a solvent, or each component may be separated by heat or mechanical action.
When separating each component, the action of a poor solvent or swelling agent for either component may be utilized. Then, a fiber bundle in which the average fineness of fine fibers is 0.0001 to 0.1 denier is obtained. Furthermore, in the case of the above-mentioned adhesive fibers, the sizing agent is removed to obtain fiber bundles. The fiber bundle thus obtained is preferably one in which the fine fibers constituting it have a small fineness. In other words, if the fineness is large and the fiber bundles are thick, blood streaks will appear on the surface of the product, which will impair its appearance and increase its stiffness, resulting in a product that does not have the solid feel of natural leather. becomes. From this point of view, what is preferable as a special fiber is a fiber bundle of at least about 500 fine fibers with an average single fineness in the range of 0.0001 to 0.03 denier, and a fiber bundle with a fineness of about 0.5 to 0.5.
It is a 15 denier fiber. It is industrially advantageous to make such special fibers from sea-island fibers.

In addition, the resin mainly composed of elastic polymer contained in the entangled nonwoven fabric should have a recovery rate of at least 50% when stretched 100%, or a rebound recovery rate of at least 90 degrees when folded in half. Such resins are preferred. This elastic recovery behavior is not limited to the inherent elasticity of the resin, but also resins that exhibit elastic behavior due to plasticization, resins that exhibit elastic behavior due to a formed structure such as sponging, or resins that exhibit high elastic behavior. It is achieved even if
Examples of such resins include polyurethane,
Synthetic rubber, natural rubber, vinyl chloride polymer or copolymer, such as polyurethaneurea, polyurea, acrylic ester polymer or copolymer, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, polyisoprene, polybutadiene, Examples include polyester. In particular, when a flexible and stiff sheet material is intended, a polymer consisting of an elastic component (soft segment) and an inelastic component (hard segment) is preferred. Such polymers include polyurethane elastomers, polyurethane urea elastomers, and polyester elastomers. These polymers may be used by selecting one or more polymers having appropriate stiffness depending on the desired feel performance of the leather-like sheet material.

The means for incorporating the resin into the entangled nonwoven fabric include a resin solution, a dispersion such as an emulsion or paste, or a liquid in which another type of resin is finely dispersed in a solution of at least one type of resin. So-called wet coagulation, which involves impregnating a non-woven fabric with resin, and then treating it with a non-solvent resin (including solvent-non-solvent systems), electrolyte solution, etc., so-called dry coagulation, which treats it with dry heat or a non-solvent vapor atmosphere, or a combination of both. By coagulating, the resin is made to exist in a porous manner within the entangled nonwoven fabric. Furthermore, in order to avoid excessive rebound in texture and reduce bending stiffness to give a solid feel similar to natural leather, the fiber to resin ratio should be 85:15.
The ratio is 45:55 to 45:55, preferably 80:20 to 55:45, and the amount of resin impregnated is selected to suit the desired leather-like sheet material. For example, it is determined as appropriate based on the bending stiffness of the special fiber, the density of the entangled nonwoven fabric, the stiffness of the resin, processability, etc.

Next, the surface coating layer of the leather-like sheet material should be made of a resin mainly composed of an elastic polymer, such that at least two layers of the resin have an elongation of 100% or more.
The recovery rate when stretched is at least 50%, or 2
Preferably, the resin has a rebound recovery degree of at least 90 degrees when folded. This elastic recovery behavior is not limited to the inherent elasticity of the resin, but may also be the elastic behavior exhibited by plasticization. Examples of resins that exhibit such elastic recovery behavior include polyurethane,
Examples include polyurethane urea, polyurea, vinyl chloride polymer or copolymer, polyester, polyamide, synthetic rubber, etc. Among them, elastic Polymers consisting of a component (soft segment) and an inelastic component (hard segment) are preferred. Such polymers include polymeric diols and organic diisocyanates or organic triisocyanates and diols, triols,
Non-crosslinked or crosslinked polyurethane elastomers or polyurethaneurea elastomers polymerized or polymerized from chain extenders having at least two active hydrogen atoms such as diamines or triamines, or polymeric diols and aromatics such as bisphenol A. Examples include polyester elastic resins consisting of a ring-containing diol and a chain extender, but polyurethane elastomers are most preferred.
These elastomeric resins may contain other elastomeric polymers, such as acrylic ester polymers or copolymers, acrylonitrile, butadiene copolymers, or inelastic polymers, such as modified polyamides, cellulose derivatives, methacrylic resins, and other common materials. Addition within a range that does not impair elasticity (satisfying the above conditions) also brings about favorable results in terms of abrasion resistance, dyeability, creases, mold fixation, etc.

In addition, the surface coating layer does not necessarily need to be entirely composed of elastic resin; for example, if necessary, the outermost layer or the layer near the outermost surface may be made of a discontinuous film of resin that does not satisfy the above elasticity conditions. Applying it or applying it as a thin film also brings about favorable results in terms of mold fixing properties, crease resistance, etc. It is also possible to finish the elastic resin by mixing fine particles of an inorganic substance or inorganic oxide as a gloss modifier and applying the mixture as the outermost surface layer. In such a case, silica is preferred as the fine particles.
The amount added varies depending on the required degree of gloss, but is preferably 5 to 40% by weight based on the outermost surface coating resin.

On the other hand, it is important that the bottom layer or the layer near the bottom that is in contact with the base sheet is made of a resin or resin composition that has a dye adsorption capacity of at least 50 mg/g, which will reduce the depth of color and irritation of the product. It is preferable for the following reasons. Furthermore, adding an inorganic or organic additive with a hiding power, such as a pigment, to this layer is also effective in hiding blood lines.

In addition, in the present invention, when the surface coating layer of the leather-like sheet material is a non-porous layer, at least 2
It is preferable from the viewpoint of surface performance, flexibility, drapability, color tone, etc. that the non-porous layer is composed of at least three non-porous layers, and the total thickness is in the range of 3 to 50 .mu.m.

Methods for applying such a non-porous layer to a base material sheet include, for example, applying resin to a release material in order from the surface layer, forming a film and transferring it, or creating a resin layer one by one and transferring it. Alternatively, a dispersion such as a resin solution, resin paste, or emulsion may be applied directly to the surface of the base material sheet by a roll coating method, a knife coating method, or a spray method, in which a dispersion such as a resin solution, resin paste, or emulsion is applied using a roll such as a score roll or a smooth roll. Apply sequentially to form a non-porous layer. Note that it is recommended that the surface of the base material sheet to which the non-porous layer is applied be smoothed or embossed in advance, such as by pressing it against a heating plate, to provide a clean surface coating layer and prevent the formation of blood streaks. It is effective in suppressing

Further, the surface coating layer of the leather-like sheet article is composed of at least two resins mainly composed of an elastic polymer.
In the case of a non-porous layer, at least one of the surface non-porous layers is a colored layer. The surface non-porous layer has a total thickness of about 3 to 50 microns. However, if the thickness cannot be measured, for example if the thickness of the surface non-porous layer is not uniform depending on the location, it may be approximately 3.5 to
The thickness is such that 60g/m ² of resin is applied. The resin or resin composition forming each non-porous layer has a different resin composition or type of resin between each non-porous layer, and the resin or resin has different dye distribution behavior when dyed under the same conditions. The non-porous layer on the side in contact with the base sheet is preferably a resin having the ability to adsorb a dye of at least 50 mg/g, especially in terms of depth and clarity of color tone and balance in crease formation. Alternatively, a resin composition to which an additive with hiding power, such as a pigment, is added is used.

Next, in the case of a leather-like sheet material whose surface coating layer is porous, an elastic polymer composition containing a foaming agent is applied to one side of the base sheet material and foamed by heating, or one surface of the base sheet material is heated and foamed. A solution composition or dispersion of an elastic polymer is applied to a surface and coagulated by a wet or dry method, or a fiber entangled body is made to contain an elastic polymer composition and then a solution composition or dispersion of an elastic polymer is applied. After application, a surface porous coating layer is formed by wet coagulation or the like.

The leather-like sheet material produced by the above method is finished by shaping the surface, coloring it, and subjecting it to a softening treatment. In this case, by containing a softening agent that does not damage the structure of the sheet, such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer, wax, cationic surfactant, etc.
It is possible to increase flexibility, and at the same time, these processing agents can also give a feeling of solidity closer to that of natural leather.

The present invention is characterized in that the surface of the leather-like sheet product obtained above is subjected to low-temperature plasma treatment.

Low-temperature plasma is defined as a plasma generated during a discharge characterized by an average electron energy of 10 eV (10 ⁴ - 10 ⁵ K) and an electron density of 10 ⁹ - ^{10 12} cm ^-3 .
It is also called non-equilibrium plasma because there is no equilibrium between the electron temperature and the gas temperature. Electrons, ions, atoms, molecules, etc. are mixed in the plasma generated by discharge.

Low-temperature plasma consists of gases such as argon, nitrogen, hydrogen, oxygen, etc. in a vacuum system of 0.01 to 10 Torr.
It is produced by continuously introducing air, carbon monoxide, carbon dioxide, etc. into the system and applying a voltage between the electrodes. The type of gas is selected depending on the purpose of processing.
Any frequency power source can be used to apply the voltage. In terms of sustainability and uniformity of discharge,
1KHz to 10GHz is preferable. In terms of plasma uniformity in the width direction of the electrode, it is preferable to use 1 KHz to 1 MHz, and if it exceeds 1 MHz and the length of the electrode exceeds 1 m, processing spots are likely to occur in the length direction. 100 again
Below Hz, the edge effect of the electrode tends to occur, and arc discharge tends to occur at the edge. Further, as the current, alternating current, direct current, biased alternating current, pulse waves, etc. can be used.

Electrodes can be divided into internal electrode types, which are placed inside the vacuum system, and external electrode types, which are placed outside the vacuum system. However, with the external electrode type, as the equipment becomes larger, the plasma tends to move particularly to the surface of the workpiece. During this time, the activity is lost, the plasma is scattered, and the plasma concentration is diluted, resulting in little processing effect. On the other hand, the internal electrode method has a greater processing effect than the external electrode method because the discharge electrode can be installed near the object to be treated.

Electrode shapes can be divided into symmetrical and asymmetrical. In the case of a large plasma processing apparatus where the processing width of the object to be processed is large and therefore a large electrode is required, symmetrical electrodes have more disadvantages. For example, it is almost impossible to flow gas uniformly between large electrodes, and the electric field is likely to be disturbed at the ends of large electrodes, resulting in uneven processing. Therefore, in the case of a large plasma processing apparatus, an asymmetric electrode is preferable. The shape of the electrode on the side that does not come in contact with the object to be processed can be arbitrarily selected from one or more cylindrical shapes, or rod-like shapes with a polygonal cross section having an acute angle, but cylindrical shapes are preferred. In addition, the shape of the electrode on the side that comes into contact with the object to be processed can be drum-shaped, plate-shaped, or modified shapes thereof, but the shape and combination thereof are not limited to these. It's not something you can do. Further, the material of the electrodes can be metals such as stainless steel, copper, iron, aluminum, etc., and may be coated with glass, ceramics, etc., if necessary. Naturally, these electrodes may be water-cooled if necessary, and the cooling temperature is appropriately selected depending on the object to be treated. It is desirable that the cooling water be water with as few impurities as possible, but this is not particularly the case if electrical leakage due to these impurities is not a serious problem.

Next, the gas to be introduced into the vacuum thread should be introduced as far as possible from the exhaust port of the vacuum pump and distributed as necessary. This is important in the sense of avoiding short passes of the gas within the vacuum system, and is also important in order to prevent processing spots on the object to be processed.

The degree of vacuum for generating low-temperature plasma is usually 0.01 to 10 Torr, but according to the results of studies by the present inventors, 0.05 to 1.0 Torr is preferable. When the degree of vacuum becomes 0.05 Torr or less, the mean free path of ions and electrons increases and the energy of accelerated particles increases, but the total number of accelerated particles that reach the object to be processed is small, and processing efficiency is not good. Moreover, in order to maintain the temperature at 0.05 Torr or less while introducing gas into a large processing chamber, a vacuum pump with a very large displacement is required, which is not desirable in terms of equipment cost. When the degree of vacuum becomes 1 Torr or more, the mean free path of ions, electrons, etc. becomes small, the energy of accelerated particles becomes small, and processing efficiency deteriorates even though the total number of accelerated particles is large.

Thinking in this way, the mean free path of an accelerated particle, in other words, the degree of vacuum P that determines the distance over which a charged particle is accelerated by an electric field and the number of accelerated particles, and the degree of vacuum P that determines the number of accelerated particles, and the accelerated particle loses its energy or activity. It is conceivable that some optimal relationship exists between the distance d between both electrodes, which determines the probability that the object can be reached without any damage. As a result of considering this point, we found that 1≦d≦10 (cm) and 0.05<
It has been found that the processing efficiency is good even when the degree of vacuum and the distance between the electrodes satisfy P.d<5 (Torr×cm). In other words, the processing efficiency was good when d was set small when the pressure was high, and when d was set large when the pressure was low. Furthermore, regarding the relative position of the sheet material placed between the electrodes, it is better to place the sheet material in contact with one of the electrodes for better processing efficiency. In addition, if you do not want to apply too much tension to the sheet object or do not want the sheet object to wrinkle, use a type that allows the sheet object and electrode to move together, such as placing the sheet object in contact with a drum electrode. However, it is desirable to have a device that moves the sheet material while rotating the drum. In fact, microscopic wrinkles often cause processing spots. If there is no need to pay much attention to tension or wrinkles, for example, a sheet may be placed in contact with a plate electrode, and the sheet may be moved by sliding on the electrode. However, if a sheet is placed in contact with one of the electrodes, it has the disadvantage that the treatment effect can only be obtained on the surface that is not in contact with the electrode surface. Naturally, after single-sided processing, double-sided processing becomes possible by passing the sheet material between electrodes arranged oppositely to the sheet material. In normal cases, as is the case with the present invention, the treatment effect on only one side is often sufficient;
This type is preferable from the viewpoint of processing efficiency.

Next, from the viewpoint of uniformity of treatment, both electrodes must be held in parallel and must be arranged at right angles to the traveling direction of the leather-like sheet material to be treated. If this condition is not satisfied, processing unevenness will occur in the width direction of the sheet material. Furthermore, the width of both electrodes must be at least 5 cm longer than the width of the leather-like sheet material to be treated. This is to eliminate electric field non-uniformity at the ends of the electrodes.
When this length is less than 5 cm, the width direction of the sheet object
In particular, the processing effect on both sides is different from that near the center, which is undesirable.

Plasma processing equipment is a continuous type in which a sheet material enters a vacuum discharge treatment tank continuously from the atmosphere and is then rolled up in the atmosphere; a plasma processing device in which the sheet material is placed in a preliminary vacuum system and can be moved to a processing chamber; This refers to a processing chamber in which sheet objects are arranged as partitions, but it does not necessarily have to be a type in which the sheet objects are movable.

There are two electrical connection methods for the discharge electrode: a grounded type in which the low voltage electrode and its circuit are connected to the earth, and an ungrounded type in which the discharge electrode and its circuit are insulated from the earth. can be processed by either type of processing device, but the non-grounded type has a greater processing effect than the grounded type. In other words, in the case of a non-grounded type in which the discharge electrode and discharge circuit are insulated from the grounded can (metal can made of stainless steel or the like that constitutes the plasma device), the potential of the electrode in contact with the sheet material and the can The potential of the can (earth potential because it is grounded) is different, and the can body does not act as an electrode, and discharge mainly occurs between the two electrodes. Therefore, the plasma effectively acts on and processes the sheet material without being diluted, and the processing effect is significantly improved.At the same time, the processing effect is significantly greater with less discharge power than the grounded type, and the specified effect can be achieved in a short time. As a result, the device can be made smaller, or in other words, the equipment cost can be reduced. Furthermore, since the discharge power is small, the running cost can be reduced to a fraction of a fraction, making it an excellent method.

When the leather-like sheet material is subjected to low-temperature plasma treatment, the effect may vary depending on the type of gas. If the main consideration is to improve color development and matte effect, oxygen and air are effective, and in this case, the outermost layer of the leather undergoes etching treatment to form a rough surface. In this etching process,
It is advantageous for the outermost layer to contain inorganic or inorganic oxide fine particles in order to form a rough surface. When the outermost layer surface is treated with low temperature plasma,
Since the fine particles are difficult to be etched, and the outermost polymer layer is more easily etched than the fine particles, convex portions are formed around the fine particles, and concave portions are formed in the polymer matrix, resulting in a so-called uneven state. Due to the presence of these fine particles, the surface is more likely to be roughened than when plasma treatment is performed using only a polymer. Among these rough surfaces, the rough surface in the visible light wavelength region absorbs light, improves color development, and produces a matte effect. Naturally, some of the polymer parts are also crosslinked by low-temperature plasma, leading to improved color fastness.

When the gas is an inert gas such as argon or nitrogen, the effect of roughening the surface is not as remarkable as when using oxygen or air, but the crosslinking of the outermost layer polymer has a large effect of improving color fastness. Of course, if only crosslinking is considered, a gas containing carbon such as carbon monoxide is also effective. Further, a combination of gases may be used depending on the purpose.

Before the low-temperature plasma treatment, an inorganic substance or a resin, or a combination of an inorganic substance and a resin, which promotes the formation of a rough surface may be applied to the outermost layer. The inorganic substance preferably has a particle size of 0.005 to 0.3μ,
Silica is most preferred from the viewpoint of transparency. As the resin, common monomers such as urethane, vinyl, fluorine, and silicone monomers, prepolymers, polymers, and other processing agents can be used. In terms of surface durability, a combination of an inorganic substance and a resin is preferred. Application methods in this case include a method in which a mixture of an inorganic substance and a resin is applied to the upper layer surface in one step, and a method in which an inorganic substance is first applied and then a resin is applied. Further, before the low-temperature plasma treatment, water or a liquid containing an electrolyte or a conductive substance may be applied to the treated object in advance.

E Effects and uses of the present invention The leather-like sheet material obtained as described above has texture, gloss, color development, color fastness, etc. that are incomparable to conventional leather-like sheet materials.In other words, it is a natural leather. It is no exaggeration to say that it has become a leather-like sheet material. This leather-like sheet material can be used for shoes,
Not only for bags, etc., but also for clothing, interior design,
Also suitable for sports equipment and boots.

F. Examples The present invention will be specifically described below with reference to Examples, but is not limited to these Examples. Note that parts and percentages in the examples refer to weight.

Example 1 50 parts of 6-nylon and 50 parts of polyethylene were spun, and the fiber cross section of the 6-nylon was made into a multicomponent fiber with about 800 finely dispersed components using polyethylene as a dispersion medium component, which was then drawn and wound. Shrink and cut to make staples with a density of 4.3 dr, make a web with a cross wrapper, and needle punch to make a staple with a fabric weight of 750 g/
^m2 entangled nonwoven fabric was obtained. The entangled nonwoven fabric was then heat-set, rolled and surface-smoothed to form a 12% polyurethane consisting of 80 parts of polyester polyurethane and 20 parts of polyethylene ether polyurethane.
A dimethylformamide solution (hereinafter referred to as
It was solidified by immersing it in a 30% aqueous solution (DMF).
The obtained sheet material is extracted with a solvent to extract the polyethylene component of the fiber, washed, and dried to form a multicomponent fiber.
A base sheet material having a thickness of approximately 1.5 mm was obtained from a fiber-entangled nonwoven fabric modified with special fibers of nylon fine fiber bundles.

Next, the above-mentioned base sheet material was sliced at approximately the center of the thickness to obtain two sheets of approximately 0.8 mm, and the sliced surfaces were buffed with sandpaper to obtain a sheet material of approximately 0.65 mm in thickness. Ta. On the other hand, the surface during solidification was pressed onto a smooth stainless steel surface heated to 125°C to form a smooth base sheet, and a cross-linked polyether polyurethane (dyeing amount 240 mg/g with respect to metal complex dye) was applied to that surface. An aqueous dispersion with a solid content of approximately 16 g/m ² was applied using a roll coater method using a scored roll, dried to provide a first non-porous layer, and then a yellow-brown pigment was added. A 14% solution of non-crosslinked polyester polyurethane was prepared and applied with a score roll at an amount of approximately 5 g/m ² solids to provide a second non-porous layer, forming a non-crosslinked polyethylene ether polyurethane. A solution of (149 mg/g dyeing amount for metal complex dye) is applied in a solid amount of about 2 g/ ^m2 , dried to form a third non-porous layer, and then embossed to create a leather pattern. After applying a polyurethane solution with a smaller dyeing amount than the lower layer on the surface, the polymer contains 30% silica to adjust the gloss, and then dyed brown with a metal complex dye composition. After treatment with a finishing agent and softening treatment, a leather-like sheet material that was flexible and had a solid feeling similar to natural leather was obtained.

The texture of this leather-like sheet material was similar to that of natural leather, but the color development was poor, the gloss was a little too high, and the color fastness (contact staining) was grade 4 (Comparative Example 1). Contact staining refers to staining due to dry migration of dye. For measurement, white and dyed leather-like sheets are glued together and treated in hot air at 70°C for 20 hours, and then the degree of white contamination is graded on a gray scale.

Next, the equipment used for low-temperature plasma treatment was an internal electrode type asymmetrical electrode using a bar and a drum.The diameter of the bar was 22mm, and the equipment was made up of 60 stainless steel pipes with a length of 800mm. used. The drum used was made of stainless steel and had a diameter of 1000 mm and a width of 600 mm. Both electrodes at 30℃
is controlled by water cooling. The leather-like sheet material can be unwound and wound up in the discharge treatment chamber, and since the drum is rotatable, it can be moved in contact with the drum electrode. The discharge electrode and its circuit were non-grounded. The power supply is a 40KVA AC frequency power supply of 110KHz AC, and the output is
I used a vacuum tube type that can add up to 20Kw. Plasma discharge conditions are oxygen gas 30
/hr, degree of vacuum 0.15 Torr, distance between both electrodes 5 cm,
Therefore, P×d=075 Torr·cm. The plasma treatment time was 120 seconds.

This low-temperature plasma-treated leather-like sheet material has an appearance, texture, weight, and flexibility similar to natural leather, and has particularly excellent color development and a mild matte gloss, as well as color fastness. (Contact stain) was good at grade 4 to 5.

Example 2 55 parts of polyethylene terephthalate with a solution viscosity [η] = 0.74 and 45 parts of polyethylene were split and spun, and the fiber cross section of the polyethylene terephthalate became a finely dispersed component of about 670 with polyethylene as the dispersion medium component. Create and draw multicomponent fibers,
Crimped and cut into staples with a fineness of 5.1 dr,
A web was made using a random webber and needle punched to obtain a bonded nonwoven fabric with a basis weight of approximately 745 g/m ² . Next, the entangled nonwoven fabric was impregnated with a 5% aqueous solution of polyvinyl alcohol, dried and heat-set in a heating zone at 135°C, and further smoothed. A polyurethane composition of 70 parts of polycaprolactone polyurethane and 30 parts of polyacrylic acid ester was added to this entangled nonwoven fabric.
% dimethylformamide solution, coagulate in a 40% dimethylformamide aqueous solution, further extract the polyethylene component of the fiber with hot perchlorethylene, wash to remove polyvinyl alcohol, etc., and dry to obtain a polyethylene terephthalate fine fiber bundle. The thickness of the fiber-entangled nonwoven fabric modified into special fibers is approx.
A 1.6 mm base sheet was obtained.

Next, the surface of the base sheet was smoothed by contacting with the surface of the heating plate, and 50 parts of an easily dyeable polyurethane (dyeing amount: 166 mg/g) dispersion and self-crosslinking polyacrylic ester were dispersed on the smooth surface. 50 parts of the liquid were mixed, and a solids amount of approximately 25 g/m ² was roll coated using a scored roll and dried to form a non-porous layer. Next, a polyether-based polyurethane solution with a solid content of 4 g/m ² was roll-coated with a score roll, dried and embossed, and a polyurethane-based polyurethane solution containing 25% of 7 mμ silica was then applied. A resin solution was applied in an amount of about 1.5 g/m ² in solid form to adjust the gloss, and dyed with a disperse dye to obtain a brown leather-like sheet. This sheet material is subjected to a softening finishing treatment, and has a thickness of 1.55 mm, a basis weight of 620 g/m ² , an apparent density of 0.400 g/cm ³ , and a moisture permeability of 1205 g/m ² /day. The drapability measured by slicing it into 0.5 mm pieces was 0.54, and it had the flexibility and solid feel of natural leather.
The color fastness (contact stain) was 3rd to 4th grade. In addition, the drape coefficient is calculated according to the method of JISL1079.
In addition, moisture permeability is a value measured by the method of JIS K6549.

This leather-like sheet material was subjected to low-temperature plasma treatment in the same manner as in Example 1, except that the gas was changed to argon. The obtained leather-like sheet material had an appearance, feel, weight, and flexibility similar to natural leather, and had a good color fastness (contact stain) of grade 4 to 5.

Example 3 A mixed fiber was made from 50 parts of 6-nylon and 50 parts of polyethylene. This mixed fiber is in the form of 6-nylon present as a component of about 1250 microfibers in the cross section of the fiber. This mixed fiber is stretched to improve its fineness.
A web was made from the staples obtained by crimping and cutting the fibers of 4.1 dr, which were then needle-punched to form a nonwoven fabric with a fabric weight of 810 g/m ² . Then, 85 parts of polyester polyurethane and polyether polyurethane were added to the processed nonwoven fabric obtained by impregnating it with a 5% aqueous solution of polyvinyl alcohol, drying it, and heat-setting it.
6- A sheet material was made by modifying special fibers in the form of nylon fine fiber bundles.

Next, the above-mentioned sheet material was sliced at approximately the center of the thickness to obtain two sheet materials, and then the sliced surfaces were buffed with sandpaper to obtain a sheet material with a thickness of 0.65 mm and to form a fluffy surface. . On the other hand, the surface during solidification was smoothed by pressing it against a mirror surface of a stainless steel belt heated to 130°C to obtain a base sheet () with a smooth surface. Easy-to-dye cross-linked polyether polyurethane on the smooth surface (dyeing amount 215 mg/g)
A dispersion with a concentration of 40% was coated with a scoring roll in an amount of 20 g/m ² as a solid content, dried to form a first non-porous layer, and then polyether polyurethane (dyed amount 139 mg/g) was applied. ) was coated with a scoring roll to form a second non-porous layer at a solid content of 6 g/m ² , followed by hot embossing and molding, and then 20% silica to resin. A third non-porous layer was formed by coating a gloss-adjusting resin composition liquid containing the liquid with a scoring roll in an amount of about 1.4 g/m ² as a solid content, and the total non-porous layer had a thickness of about 26 μm. I made it. This sheet material was dyed with a metal salt dye, and subjected to a softening agent treatment and a rubbing treatment to obtain a leather-like sheet material with flexibility similar to natural leather and a heavy feel. This sheet material showed no blood lines and was excellent. Thickness 0.6mm, apparent density
It had a moisture permeability of 0.42 g/cm ³ , a moisture permeability of 1142 g/m ² /day, and a drapability of 0.50. However, this leather-like sheet material was somewhat poor in color development and mild matte luster, and its color fastness (contact staining) was 3rd to 4th grade.

This leather-like sheet material was subjected to low-temperature plasma treatment in the same manner as in Example 1, except that the plasma treatment was performed for 60 seconds. The obtained product had excellent appearance and texture, as well as excellent color development and a mild matte luster, and the color fastness (contact stain) was grade 4.

Claims (1)

[Claims] 1. A non-porous coating layer and/or a porous coating layer made of a polymer mainly composed of an elastic polymer are provided on the surface of a porous base layer in which an elastic polymer is contained in a fiber entangled body, The surface of the leather-like sheet whose outermost surface coating layer contains inorganic fine particles is subjected to a low-temperature plasma etching treatment to make the surface of the leather-like sheet uneven. Method. 2. The method for producing a leather-like sheet material according to claim 1, wherein the polymer constituting the surface coating layer is a polymer mainly composed of polyurethane. 3. The leather-like material according to claim 1 or 2, wherein the surface coating layer is non-porous, and the coating layer is a laminate of at least two non-porous coatings having different dye adsorption properties. Method for manufacturing sheet products. 4 The surface coating layer is porous, and the coating layer has a thickness of 0.02 to 0.5 mm obtained by a wet method or a dry method.
The method for producing a leather-like sheet material according to any one of claims 1 to 3, which is a porous film layer having an apparent density of 0.2 to 0.75 g/cm.