JPS6139437B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has a grain layer formed of a composite mainly consisting of a superentangled layer in which ultrafine fibers and/or bundles thereof are densely intertwined, and a resin present in the voids, and is water repellent. , concerning a novel artificial leather with excellent oil repellency. Conventionally, artificial leather based on nonwoven fabric is well known. Since such artificial leather is made of a nonwoven fabric coated with an elastic polymer material such as polyurethane resin, it is characterized by being easy to care for, waterproof, and easy to handle. However, on the other hand, polymeric substances such as polyurethane have the major disadvantage of making the texture and touch of artificial leather rubber-like, and also reducing breathability and moisture permeability. On the other hand, if the content of polymeric substances is lowered, properties such as mechanical strength and surface abrasion will decrease, making it impractical, and even if moisture permeability and air permeability are high,
Water-repellent and oil-repellent treatments have little effect, and water leakage cannot be avoided. In other words, in the past, it has not been possible to easily obtain artificial leather using nonwoven fabric that has all of the appearance quality, texture, mechanical strength, surface strength, gas permeability, and waterproof and oil-proof properties. The object of the present invention is to provide a new water- and oil-repellent artificial leather having all of these properties. In order to achieve this object, the present invention has the configurations as described in the claims. In other words, when ultrafine fibers of 0.2 denier or less are intertwined extremely densely, the water repellent and oil repellent effects are enhanced, and properties such as air permeability and moisture permeability can be maintained, and a small amount of resin can be included in the super entangled layer. This gives it an excellent appearance and function as a silver surface. The water-repellent and oil-repellent artificial leather of the present invention is
Fluorine-based and/or silicon-based compounds are attached to the super-entangled layer, which consists of ultra-fine fibers that are extremely densely intertwined with a distance between fiber entanglements of 200μ or less, resulting in extremely high water and oil repellency. In addition to having the characteristics of
It has been discovered that artificial leather has extremely excellent moisture permeability and air permeability, as well as excellent texture and feel, and also has excellent mechanical strength and surface strength due to the presence of a superentangled layer. The fiber structure in the superentangled layer of the artificial leather of the present invention requires that ultrafine fibers and/or bundles thereof are densely intertwined with each other. In other words, the fiber entanglement density is high. Such sheets do not require a thick resin layer when forming the grain surface, and by integrating a small amount of resin with the superentangled layer, they have high gas permeability but low liquid permeability such as water. Water and oil repellency can be enhanced while keeping the amount small. The intertwining density of the fibers in the superentangled layer needs to be 200μ or less, expressed as the distance between fiber intertwining points, which will be described later. Structures with this value greater than 200 μ, for example, fiber structures with little entanglement in which the fibers are entangled only by needle punching, or structures in which ultra-fine fibers or bundles thereof are simply arranged in a plane, or ultra-fine fibers or Structures in which bundles of these fibers grow densely in a fluff-like manner on the surface of the base material and are left to age to create a surface have little or no entanglement of fibers, making it difficult to impart high water and oil repellency. , when subjected to abrasion, rubbing, repeated shearing force, etc.
It is not preferred as silver-covered artificial leather because the surface tends to become fluffy and cracks occur. More preferable results can be obtained when the distance between fiber entanglement points is 100μ or less. Here, the distance between fiber entanglement points is a value obtained by the following method, and the smaller the value, the denser the intertwining. FIG. 1 is an enlarged schematic diagram of the constituent fibers in the grain layer when observed from the surface side. The constituent fibers are f ₁ , f ₂ , f ₃ , ..., and the point where any two fibers f ₁ , f ₂ are intertwined is a ₁ , and the fiber f ₂ on top at a ₁ is the other point. Trace the intersection point below the fibers of a ₂
(intersection point of f ₂ and f ₃ ). Similarly, a ₃ , a ₄ , a ₅ ……
shall be. Next, the linear horizontal distances between the intersecting points obtained in this way are a ₁ a ₂ , a ₂ a ₃ , a ₃ a ₄ , a ₄ a ₅ , a ₅ a ₆ , a ₆ a ₇ ,
a ₇ a ₃ , a ₃ a ₈ , a ₈ a ₇ , a ₇ a ₉ , a ₉ a ₆ ... is measured, and the average value of these many measured values is determined and this is taken as the distance between fiber entanglement points. One of the characteristics of the artificial leather of the present invention, which has such a superentangled layer, is that even though it has high moisture permeability and air permeability, it has a low water permeability, which is related to its extremely high water and oil repellent effects. It seems that there is a mechanism, but the mechanism is not necessarily clear. What is water permeability referred to here?
It refers to the amount of water (ml) that passes per minute ^per cm2 of artificial leather under a pressure of 120mmHg. The artificial leather of the present invention having a superentangled layer with a distance between fiber entanglement points of 200μ or less often has this value of 1000ml or less, and for those with a fiber interlacement distance of 100μ or less, this value is often 500ml or less. However, this value is only a guideline,
This value decreases when a large amount of resin is applied or impregnated, so it should only be used as a measure of the denseness of the fiber. In conventional nonwoven fabrics, those with high moisture permeability and air permeability always have high water permeability, so even if they were treated to be water-repellent or oil-repellent, it was not possible to obtain a highly effective non-woven fabric. In addition, the lower layer of the superentangled layer is mainly intertwined with ultrafine fiber bundles, and the ultrafine fibers and/or their bundles in the superentangled layer are the ultrafine fiber bundles in the lower layer that are branched and intertwined more densely. A fiber structure in which the fibers are substantially continuous in the superentangled layer and the lower layer, and the degree of branching changes continuously at the boundary between the two layers has a unified texture. It is preferably used because artificial leather is obtained and the superentangled layer and the lower layer do not peel off. Here, the thickness of the ultrafine fiber bundles in the superentangled layer does not need to be the same for all bundles, but is as thin as possible compared to the thickness of the bundle in the lower layer (the number of fibers included in the bundle is smaller than that in the lower layer). It is preferable to have as little as possible since it is less likely to cause unevenness on the surface of the artificial leather. The lower layer of the superentangled layer also has a structure in which ultrafine fiber bundles and branched ultrafine fibers are intertwined. It is also preferable to have a fiber structure in which the fibers are formed by continuous ultrafine fibers in the lower layer, and these fibers are closely intertwined with each other. Furthermore, the lower layer of the superentangled layer has ultrafine fibers intertwined randomly, and the superentangled layer may have a fiber structure mainly consisting of ultrafine fibers that are substantially continuous from the ultrafine fibers in the lower layer. It is also preferably used. However, in this case, the distance between fiber entanglement points in the superentangled layer tends to be slightly larger than in the case where the ultrafine fiber bundles are branched as described above, so from the viewpoint of the density of the superentangled layer and the water- and oil-repellent effects, It is particularly preferable to branch the ultrafine fiber bundle. In such a preferred embodiment, the fibers constituting the nonwoven fabric have a structure in which single microfibers form bundles in some parts and branch in other parts, so that they cannot be separated into single fibers and bundles. This is what we are doing. These preferred embodiments of the present invention are illustrated in FIG. As the ultrafine fibers used in the present invention, ultrafine fibers directly produced by a method such as melt blowing or super draw may be used. It is also preferable to use ultrafine fiber-forming fibers and convert them into ultrafine fibers at an appropriate time during the processing process. Such ultra-fine fiber-forming fibers include, for example, fibers made by converging ultra-fine fibers immediately after spinning and lightly adhering them into a single fiber, fibers with a chrysanthemum-shaped cross section in which one component is radially interposed between other components, and multilayer fibers. Bimetallic fibers, multilayer bimetallic fibers with a donut-shaped cross section, sea-island fibers made by melt-mixing two or more components and spinning them, a large number of ultrafine fibers that are continuous in the fiber axis direction and assembled in an array and bound and/or unified by other components. These are polymeric mutual array fibers that are partially bonded to form a single fiber, and two or more types of these fibers may be mixed or used in combination. Ultrafine fiber-forming fibers having a cross section in which a plurality of cores are interveningly bonded and/or partially bonded by other components can be relatively easily obtained by applying physical action or removing bonding components. Therefore, it is preferably used. FIG. 3 shows an example of the cross-sectional shape of the microfiber-forming fiber that is preferably used. In addition, ultrafine fiber-forming fibers made of multicomponents that yield fiber bundles mainly composed of ultrafine fibers of 0.2 denier or less, preferably 0.05 denier or less, more preferably 0.005 denier or less when at least one component is dissolved and removed, It is more preferably used because the denseness of the interlaced layer is high, resulting in high water- and oil-repellent effects, as well as artificial leather having a supple texture and smooth surface. Further, the ultrafine fiber in the present invention is made of a polymeric substance having fiber-forming ability, such as nylon 6, nylon
66, nylon 12, polyamides such as copolymerized nylon, polyesters such as polyethylene terephthalate, copolymerized polyethylene terephthalate, polybutylene terephthalate, copolymerized polybutylene terephthalate, polyolefins such as polyethylene and polypropylene, polyurethane, polyacrylonitrile, and vinyl polymers. can give. In addition, examples of the binding component or the component to be dissolved and removed of the microfiber-forming fiber include polystyrene, polyethylene, polypropylene, polyamide, polyurethane, copolymerized polyethylene terephthalate that is easily soluble in alkaline solutions, polyvinyl alcohol, and copolymerized polyvinyl alcohol. , a styrene-acrylonitrile copolymer, a copolymer of styrene and an alcohol ester of acrylic acid and/or a higher alcohol ester of methacrylic acid, and the like. Polystyrene, styrene-acrylonitrile copolymers, and copolymers of styrene and higher alcohol esters of acrylic acid and/or higher alcohol esters of methacrylic acid are preferably used in terms of ease of spinning and ease of dissolution and removal. Furthermore, a copolymer of styrene and a higher alcohol ester of acrylic acid and/or a higher alcohol ester of methacrylic acid is more preferably used because it can obtain a fiber with a high draw ratio and high strength. Furthermore, in order to make the ultrafine fibers more likely to branch, it is preferable to use a mixture of 0.5 to 30% by weight of a polymer such as polyethylene glycol in the binding component or the dissolving and removing component. The fineness of such microfiber-forming fibers is not particularly limited, but is preferably 0.5 to 10 deniers from the viewpoint of stability during spinning and ease of sheet formation. Of course, the binding component may also be used as an ultrafine fiber component. The ultrafine fibers in the superentangled layer of the present invention have a fineness of
It is preferably 0.2 denier or less. If the fiber is thicker than 0.2 denier, the stiffness of the fiber is too high, which not only impairs the flexibility of the superentangled layer and the form of wrinkles on the surface, but also reduces the effectiveness of water and oil repellents even if they are attached to the fibers. This makes it difficult to form a dense and supple superentangled layer because cracks are likely to occur and the surface becomes uneven. 0.2 denier or less, preferably 0.05 denier or less, more preferably 0.05 denier or less
By using ultra-fine fibers of 0.005 denier or less, the fibers can be tightly intertwined,
Artificial leather is obtained which has a highly water- and oil-repellent effect, is smooth and supple, and has a superentangled layer that is hard to crack and feels good in the hand. Typical fluorine-based compounds used in the present invention have a fluorocarbon group in their side chain, such as perfluoroalkyl, perfluoroalkenyl allyl ether, perfluorohexacenyl, perfluorononenyl, etc., and are polyacrylic acid esters. Alternatively, it is a fluorine-containing polymer having a methacrylic acid ester polymer or the like in its main chain, and for example, polymers and copolymers of the following monomers are common. (R ₁ is hydrogen or a methyl group, R ₂ is a methyl group or an ethyl group. η is an integer from 3 to 21) The silicon-based compound used in the present invention is a silicon-based compound such as dimethylpolysiloxane or its copolymer. It is resin. It has a grain layer formed of a composite mainly consisting of a fiber structure in which the distance between the fiber entanglement points of the ultrafine fibers and/or a bundle thereof of the present invention is 200 microns or less, and a resin existing in the voids of the fiber structure. However, water-repellent and oil-repellent artificial leather in which a fluorine-based and/or silicon-based compound is attached to at least the surface of the superentangled layer can be specifically obtained by the following method. For example, by each of the methods described above, a web is formed using directly spun microfibers, microfine fiber bundles that are bundled and temporarily bonded, or filaments or cut microfiber-forming fibers, and then needle punched. After forming an entangled structure, if a high-speed fluid stream such as a columnar water stream is applied to one or both sides, the energy of the jet stream causes the ultrafine fibers in the surface layer to become entangled or branched. A superentangled layer is formed. Even in the case of ultrafine fiber-forming fibers having a structure in which a large number of ultrafine fiber components are surrounded by a bonding component, the exposed ultrafine fibers can be entangled because the high-speed fluid flow splits the bonding components. Of course, the bonded components may be dissolved and removed to form an ultrafine fiber bundle before the high-speed fluid jet is applied. Such a superentangled layer may of course be formed on both the front and back surfaces, and it is a preferable method to combine the above process with techniques such as impregnation with a binder such as polyurethane and temporary fixing treatment with a temporary fixing agent such as polyvinyl alcohol. be. Furthermore, a resin solution or dispersion is applied to the surface onto which the high-speed fluid stream has been sprayed by a method such as reverse roll coating, gravure coating, knife coating, slit coating, or spraying, and is solidified by a wet or dry method. The fibers and the resin are stacked on the surface or sheet surface, pressed, and heated as necessary to integrate the fibers and resin and at the same time smooth the surface. It is also a preferable method to subject the fiber sheet to a treatment such as pressing to smooth the surface before applying the resin. Furthermore, it is preferable to integrate the fibers and resin using an embossing roll or a textured sheet with a textured surface because integration, smoothing, and texture formation can be performed at the same time. Examples of the resin used for the silver layer include polyamide, polyester, polyvinyl chloride, polyacrylate copolymer, polyurethane, neoprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polyamino acid, and polyamino acid polyurethane copolymer. Synthetic resins such as synthetic resins, silicone resins, natural polymer resins, or mixtures of these resins. Furthermore, if necessary, plasticizers, fillers, stabilizers, pigments, dyes, crosslinking agents, etc. may be added. Polyurethane resins or polyurethane resins to which other resins and additives are added are preferably used because they yield a grain layer that has a particularly soft texture and touch and has good bending resistance. The artificial leather having the superentangled layer thus obtained may be further subjected to treatments such as coating with a finishing agent, dyeing, and rolling, if necessary. In the present invention, the above-mentioned fluorine-based compound, silicon-based compound, or both are applied to at least the surface of the superentangled layer of such artificial leather. It may be applied at any time after the formation of the superentangled layer, but
If there is a step of dissolving the ultrafine fiber-forming fibers having a binding component, the subsequent step is preferred. Usually, a process near the final stage, such as after dyeing, is preferred. The coating is applied by impregnation, padding or coating, followed by drying. If necessary, heat treatment under constant temperature and time conditions may be performed thereafter, or hot pressing such as calendering may be performed. Further, the fluorine-based compound and the silicon-based compound may be used alone or in combination.
Alternatively, both may be used in separate steps. Further, both compounds can be applied in the form of an emulsion or as a solution of trichloroethane, trichlorethylene, perchlorethylene, or the like. If the emulsion is first applied in the form of an emulsion and then applied again after heat treatment in the form of a solution, the solution can penetrate into the interior without being affected by the water repellency caused by the first application. It is also possible to use an antistatic agent or a penetrating agent together. The thus obtained water- and oil-repellent artificial leather of the present invention has high water- and oil-repellency, a supple texture, and a smooth surface feel, and has good bending resistance, shear fatigue resistance, and scratch resistance. In addition to artificial leather for clothing, shoe uppers, handbags, bags, belts,
It is preferably used for various purposes such as bags, gloves, and ball leather. The examples shown below are intended to make the present invention more clear, and the present invention is not limited thereto. In the examples, parts and percentages are by weight unless otherwise specified. Moreover, the value of the average intercrossing point distance was taken as the average value of 100 measured values. Example 1 A vinyl polymer (hereinafter referred to as AS resin) copolymerized with 20 parts of 2-ethylhexyl acrylate and 80 parts of styrene was used as a binding component, and nylon 6 was used as an ultrafine fiber component in a ratio of 60 parts and 40 parts. Mixed spun fibers of the form shown in Figure 3
Using 4.0 denier, 51 mm staples, a web with a basis weight of 480 g/m ² was formed through a card and a cross wrapper. Although the thickness of the ultrafine fiber component varied, it was 0.002 denier on average. Using this web, 2000 pieces/cm ² were produced in the same manner as in Example 1.
After needle punching and water treatment four times at 100 kg/cm ² from one side, nonwoven fabric A was found to have a super entangled layer consisting of branched ultrafine fibers and their bundles, approximately 1/5 from the surface layer. I got it. The distance between the fiber entanglement points was about 80 microns. On the other hand, about nylon 6 was made by the melt blowing method.
Spun and aggregated 0.005 denier ultrafine fibers,
Forms a random web of approximately 410g/ ^m2 , 2500 pieces/
A cm ² needle punch was performed. After shrinking this needle-punched nonwoven fabric with hot water, it was subjected to high-speed water jet treatment four times at 100 kg/cm ² from one side using the same nozzle as in Example 1, and dried. A nonwoven fabric B was obtained in which continuous fibers were loosely and randomly entangled from the surface layer inside. Also 2.4 denier, 38mm
100 parts consisting of 50 parts of polyethylene terephthalate and 6650 parts of nylon having a cross-sectional structure as shown in Figure 3.
Web formation was performed using a random web bar using hollow multilayer bimetallic fibers. The thickness of one layer in the fiber was approximately 0.005 denier. When this web was subjected to needle punching, shrinkage, and high-speed water jet treatment on one side under the same conditions as for obtaining nonwoven fabric B, it was found that the surface layer had a distance between fiber entanglement points of approximately 150 microns, and the interior was continuous from the surface layer. A nonwoven fabric C was obtained in which thick fibers were randomly bonded into bundles of concentrated fibers. Next, a mixed diol of polyethylene adipate, polybutylene adipate, and polyethylene glycol (mixing ratio 60:20:20) and p/p'-diphenyl were applied to the superentangled surfaces of each of these three types of nonwoven fabrics A, B, and C. A 10% solution of polyurethane obtained by chain-extending a methane diisocyanate prepolymer with ethylene glycol is applied with a gravure coater, dried, and then pressed through a heated embossing roll to emboss a leather-like grain pattern. did. Furthermore, the sheet from nonwoven fabric A was soaked in trichlorethylene, and the dipping and squeezing process was repeated.
The AS resin was almost completely extracted and removed, followed by drying and residual trichlorethylene was removed by evaporation. The sheet made from nonwoven fabric C was thoroughly rubbed to separate and peel off the polyethylene terephthalate and nylon 66 as much as possible. Furthermore, sheets A, B and C of the present invention were obtained by dyeing at normal pressure using a 1:2 type metal complex dye. The superentangled layers of both sheets were filled with polyurethane resin and had a beautiful silver surface similar to natural leather. Next, these sheets A, B, and C of the present invention were padded (pickup 30
%), and after drying at 100°C, heat treatment was performed at 160°C for 1 minute. Prescription 1 Asahi Guard AG-710 (fluorine-based water repellent emulsion manufactured by Asahi Glass KK) 5 parts AG Accel 700 (antistatic agent manufactured by Meisei Kagaku KK)
1 part isopropanol 2 parts water 92 parts Furthermore, it was padded (pickup 35%) in a treatment bath of the following formulation 2, dried at 100°C, and then heat-treated at 160°C for 1 minute. Formulation 2 Asahi Guard AG-650 (solvent type fluorine-based water repellent manufactured by Asahi Glass) 2 parts Boron coat (solvent type silicone water repellent manufactured by Shin-Etsu Chemical 2 parts trichlorethylene 96 parts) The artificial leather has an extremely supple and soft feel similar to that of sheepskin, and cross-sectional observation under a microscope reveals that the super entangled layer (silver layer) is made up of fine fibers that are tightly intertwined. , C shows the inner ultrafine fiber bundle, B
It was connected to a loosely intertwined layer of ultra-fine fibers. The polyurethane and finishing agent applied to these leather-like sheets were extracted and removed with a solvent, and the distance between fiber entanglement points of the constituent fibers on the surface of the grain layer was measured. The average distance between fiber entanglement points of artificial leather A is 77μ,
It was 193μ for artificial leather B and 150μ for artificial leather C. These artificial leathers of the present invention and commercially available artificial leathers for clothing (types with polyurethane coating)
The properties of the artificial leather are as shown in Table 1, and the artificial leather of the present invention has good gas permeability such as moisture permeability and air permeability, as well as excellent water repellency, whereas commercially available artificial leather has virtually no gas permeability. It was something that wasn't there. Furthermore, in the present invention, the water repellency of Types A and C, in which ultrafine fiber bundles were branched, was superior to Type B, in which the fibers were randomly intertwined.

[Table] The condition of the wound was determined.

[Brief explanation of the drawing]

FIG. 1 is an enlarged schematic diagram of the constituent fibers in the superentangled layer when observed from the surface side.
FIG. 2 is a cross-sectional view of a model showing a preferred embodiment of the fiber structure of the artificial leather of the present invention. In the figure, B indicates a superentangled layer, and A indicates an interlaced layer of ultrafine fiber bundles or an interlaced layer of ultrafine fibers. FIG. 3 illustrates the cross-sectional structure of ultrafine fiber-forming fibers preferably used in the present invention. In the figure, 1 and 1' are ultrafine fibers, and 2 and 2' in the figure are binding components.

Claims (1)

[Claims] 1. A composite material mainly consisting of a super-entangled layer in which the distance between fiber entanglement points of ultrafine fibers of 0.2 denier or less and/or bundles thereof is 200 microns or less, and a resin existing in the voids thereof. A repellent having a superentangled layer, which has a grain layer formed on at least one side thereof, and a fluorine-based compound and/or a silicon-based compound is attached to at least the surface of the grain layer. Water and oil repellent artificial leather. 2 The lower layer of the superentangled layer is mainly composed of ultrafine fiber bundles entangled with each other, and the superentangled layer is mainly composed of ultrafine fibers and/or bundles thereof branched from the ultrafine fiber bundles in the lower layer. The fibers in the superentangled layer and the superentangled layer are substantially continuous, and the degree of branching at the boundary between the two layers continuously changes. Water- and oil-repellent artificial leather with a super-entangled layer. 3. Water repellency and oil repellency having a superentangled layer according to any one of claims 1 to 2, characterized in that the ultrafine fiber bundle is obtained from polymeric mutually arranged fibers. Artificial leather. 4 Claims 1 to 4, characterized in that the ultrafine fiber bundle is obtained from mixed spun fibers.
2. A water- and oil-repellent artificial leather having a superentangled layer according to any one of Item 2. 5. Having a superentangled layer according to claims 1 to 2, wherein the ultrafine fiber bundle is obtained from multicomponent fibers that can be chemically or physically split and peeled. Water and oil repellent artificial leather. 6. Claim 1, characterized in that the ultrafine fibers are produced by a melt blowing method.
A water-repellent and oil-repellent artificial leather having a superentangled layer according to items 1 to 2.